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Diagnosis and Management of Patellofemoral Pain SyndromePhysical activity is a necessary component to maintain overall health, and is often involved in favorite hobbies such as running and participation in sport. The physical and psychological benefits of these hobbies are undeniable, but unfortunately the wear and tear they cause on the body can limit participation if pains and other signs of dysfunction are not properly addressed. In particular, the knee endures repetitive loading and various soft tissue forces during a vast majority of different activities, leading to the rise of the multifaceted patellofemoral pain syndrome (PFPS). This common cause of knee pain has been reported in as much as 25% of the general population to some degree, and those who are more active or participate in sports are especially likely to be affected.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"In vivo patellar tracking induced by individual quadriceps components in individuals with patellofemoral pain.","id":"4536516","page":"235-241","type":"article-journal","volume":"43","issue":"2","author":[{"family":"Lin","given":"Fang"},{"family":"Wilson","given":"Nicole A"},{"family":"Makhsous","given":"Mohsen"},{"family":"Press","given":"Joel M"},{"family":"Koh","given":"Jason L"},{"family":"Nuber","given":"Gordon W"},{"family":"Zhang","given":"Li-Qun"}],"issued":{"date-parts":[["2010","1","19"]]},"container-title":"Journal of Biomechanics","container-title-short":"J Biomech","journalAbbreviation":"J Biomech","DOI":"10.1016/j.jbiomech.2009.08.043","PMID":"19878947","PMCID":"PMC2813315","citation-label":"4536516","Abstract":"Patellofemoral pain is a common knee disorder with a multi-factorial etiology related to abnormal patellar tracking. Our hypothesis was that the pattern of three-dimensional rotation and translation of the patella induced by selective activation of individual quadriceps components would differ between subjects with patellofemoral pain and healthy subjects. Nine female subjects with patellofemoral pain and seven healthy female subjects underwent electrical stimulation to selectively activate individual quadriceps components (vastus medialis obliquus, VMO; vastus medialis lateralis, VML; vastus lateralis, VL) with the knee at 0 degrees and 20 degrees flexion, while three-dimensional patellar tracking was recorded. Normalized direction of rotation and direction of translation characterized the relative amplitudes of each component of patellar movement. VMO activation in patellofemoral pain caused greater medial patellar rotation (distal patellar pole rotates medially in frontal plane) at both knee positions (p< 0.01), and both VMO and VML activation caused increased anterior patellar translation (p< 0.001) in patellofemoral pain compared to healthy subjects at 20 degrees knee flexion. VL activation caused more lateral patellar translation (p< 0.001) in patellofemoral pain compared to healthy subjects. In healthy subjects the 3-D mechanical action of the VMO is actively modulated with knee flexion angle while such modulation was not observed in PFP subjects. This could be due to anatomical differences in the VMO insertion on the patella and medial quadriceps weakness. Quantitative evaluation of the influence of individual quadriceps components on patellar tracking will aid understanding of the knee extensor mechanism and provide insight into the etiology of patellofemoral pain. Copyright 2009 Elsevier Ltd. All rights reserved.","CleanAbstract":"Patellofemoral pain is a common knee disorder with a multi-factorial etiology related to abnormal patellar tracking. Our hypothesis was that the pattern of three-dimensional rotation and translation of the patella induced by selective activation of individual quadriceps components would differ between subjects with patellofemoral pain and healthy subjects. Nine female subjects with patellofemoral pain and seven healthy female subjects underwent electrical stimulation to selectively activate individual quadriceps components (vastus medialis obliquus, VMO; vastus medialis lateralis, VML; vastus lateralis, VL) with the knee at 0 degrees and 20 degrees flexion, while three-dimensional patellar tracking was recorded. Normalized direction of rotation and direction of translation characterized the relative amplitudes of each component of patellar movement. VMO activation in patellofemoral pain caused greater medial patellar rotation (distal patellar pole rotates medially in frontal plane) at both knee positions (pCopyright 2009 Elsevier Ltd. All rights reserved."},{"title":"Knee complaints seen in general practice: active sport participants versus non-sport participants.","id":"4537923","page":"36","type":"article-journal","volume":"9","author":[{"family":"van Middelkoop","given":"Marienke"},{"family":"van Linschoten","given":"Robbart"},{"family":"Berger","given":"Marjolein Y"},{"family":"Koes","given":"Bart W"},{"family":"Bierma-Zeinstra","given":"Sita Ma"}],"issued":{"date-parts":[["2008","3","19"]]},"container-title":"BMC Musculoskeletal Disorders","container-title-short":"BMC Musculoskelet Disord","journalAbbreviation":"BMC Musculoskelet Disord","DOI":"10.1186/1471-2474-9-36","PMID":"18366679","PMCID":"PMC2278141","citation-label":"4537923","Abstract":"BACKGROUND: Since knee complaints are common among athletes and are frequently presented in general practice, it is of interest to investigate the type of knee complaints represented in general practice of athletes in comparison with those of non-athletes. Therefore, the aim of this study is to investigate the differences in type of knee complaints between sport participants, in this study defined as athletes, and non-sport participants, defined as non-athletes, presenting in general practice. Further, differences in the initial policy of the GP, medical consumption, and outcome at one-year follow-up were also investigated. METHODS: Patients consulting their GP for a new episode of knee complaints were invited to participate in this prospective cohort study. From the total HONEUR knee cohort population (n = 1068) we extracted patients who were athletes (n = 421) or non-athletes (n = 388). RESULTS: The results showed that acute distortions of the knee were significantly more diagnosed in athletes than in non-athletes (p = 0.04). Further, more athletes were advised by their GP to 'go easy on the knee' than the non-athletes (p < 0.01), but no differences were found in number of referrals and medication prescribed by the GP. The medical consumption was significantly higher among athletes; however, no significant differences were found between the two groups for recovery at one-year follow-up. CONCLUSION: There are no major differences in the diagnosis and prognosis of knee complaints between athletes and non-athletes presented to the GP. This implies that there are no indications for different treatment strategies applied in both groups. However, athletes are more often advised to 'go easy on the knee' and to rest than non-athletes. Further, there is a trend towards increased medical consumption among athletes while functional disability and pain are lower than among the non-athletes.","CleanAbstract":"BACKGROUND: Since knee complaints are common among athletes and are frequently presented in general practice, it is of interest to investigate the type of knee complaints represented in general practice of athletes in comparison with those of non-athletes. Therefore, the aim of this study is to investigate the differences in type of knee complaints between sport participants, in this study defined as athletes, and non-sport participants, defined as non-athletes, presenting in general practice. Further, differences in the initial policy of the GP, medical consumption, and outcome at one-year follow-up were also investigated.METHODS: Patients consulting their GP for a new episode of knee complaints were invited to participate in this prospective cohort study. From the total HONEUR knee cohort population (n = 1068) we extracted patients who were athletes (n = 421) or non-athletes (n = 388).RESULTS: The results showed that acute distortions of the knee were significantly more diagnosed in athletes than in non-athletes (p = 0.04). Further, more athletes were advised by their GP to 'go easy on the knee' than the non-athletes (p CONCLUSION: There are no major differences in the diagnosis and prognosis of knee complaints between athletes and non-athletes presented to the GP. This implies that there are no indications for different treatment strategies applied in both groups. However, athletes are more often advised to 'go easy on the knee' and to rest than non-athletes. Further, there is a trend towards increased medical consumption among athletes while functional disability and pain are lower than among the non-athletes."}]1,2 PFPS affects both young and old, and is a particular concern for women, who are 2.23 times more likely to develop it than men.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Changes in patellofemoral joint contact pressures caused by vastus medialis muscle weakness.","id":"1042017","page":"595-601","type":"article-journal","volume":"27","issue":"6","author":[{"family":"Sawatsky","given":"Andrew"},{"family":"Bourne","given":"Doug"},{"family":"Horisberger","given":"Monika"},{"family":"Jinha","given":"Azim"},{"family":"Herzog","given":"Walter"}],"issued":{"date-parts":[["2012","7"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2011.12.011","PMID":"22226076","citation-label":"1042017","Abstract":"BACKGROUND: Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.\n \n \nMETHODS: Experiments were performed using New Zealand white rabbits (mass 4.9-7.7 kg, n=12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.\n \n \nFINDINGS: Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.\n \n \nINTERPRETATION: We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.\n \n Copyright ? 2011 Elsevier Ltd. All rights reserved.","CleanAbstract":"BACKGROUND: Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.\n\n\nMETHODS: Experiments were performed using New Zealand white rabbits (mass 4.9-7.7 kg, n=12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.\n\n\nFINDINGS: Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.\n\n\nINTERPRETATION: We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.\n\nCopyright ? 2011 Elsevier Ltd. All rights reserved."},{"title":"Gender differences in the incidence and prevalence of patellofemoral pain syndrome.","id":"1753407","page":"725-730","type":"article-journal","volume":"20","issue":"5","author":[{"family":"Boling","given":"M"},{"family":"Padua","given":"D"},{"family":"Marshall","given":"S"},{"family":"Guskiewicz","given":"K"},{"family":"Pyne","given":"S"},{"family":"Beutler","given":"A"}],"issued":{"date-parts":[["2010","10"]]},"container-title":"Scandinavian Journal of Medicine & Science in Sports","container-title-short":"Scand J Med Sci Sports","journalAbbreviation":"Scand J Med Sci Sports","DOI":"10.1111/j.1600-0838.2009.00996.x","PMID":"19765240","PMCID":"PMC2895959","citation-label":"1753407","Abstract":"The purpose of this investigation was to determine the association between gender and the prevalence and incidence of patellofemoral pain syndrome (PFPS). One thousand five hundred and twenty-five participants from the United States Naval Academy (USNA) were followed for up to 2.5 years for the development of PFPS. Physicians and certified athletic trainers documented the cases of PFPS. PFPS was defined as retropatellar pain during at least two of the following activities: ascending/descending stairs, hopping/jogging, prolonged sitting, kneeling, and squatting, negative findings on examination of knee ligament, menisci, bursa, and synovial plica, and pain on palpation of either the patellar facets or femoral condyles. Poisson and logistic regressions were performed to determine the association between gender and the incidence and prevalence of PFPS, respectively. The incidence rate for PFPS was 22/1000 person-years. Females were 2.23 times (95% CI: 1.19, 4.20) more likely to develop PFPS compared with males. While not statistically significant, the prevalence of PFPS at study enrollment tended to be higher in females (15%) than in males (12%) (P=0.09). Females at the USNA are significantly more likely to develop PFPS than males. Additionally, at the time of admission to the academy, the prevalence of PFPS was not significantly different between genders.? 2009 John Wiley & Sons A/S.","CleanAbstract":"The purpose of this investigation was to determine the association between gender and the prevalence and incidence of patellofemoral pain syndrome (PFPS). One thousand five hundred and twenty-five participants from the United States Naval Academy (USNA) were followed for up to 2.5 years for the development of PFPS. Physicians and certified athletic trainers documented the cases of PFPS. PFPS was defined as retropatellar pain during at least two of the following activities: ascending/descending stairs, hopping/jogging, prolonged sitting, kneeling, and squatting, negative findings on examination of knee ligament, menisci, bursa, and synovial plica, and pain on palpation of either the patellar facets or femoral condyles. Poisson and logistic regressions were performed to determine the association between gender and the incidence and prevalence of PFPS, respectively. The incidence rate for PFPS was 22/1000 person-years. Females were 2.23 times (95% CI: 1.19, 4.20) more likely to develop PFPS compared with males. While not statistically significant, the prevalence of PFPS at study enrollment tended to be higher in females (15%) than in males (12%) (P=0.09). Females at the USNA are significantly more likely to develop PFPS than males. Additionally, at the time of admission to the academy, the prevalence of PFPS was not significantly different between genders.? 2009 John Wiley & Sons A/S."}]3,4 PFPS is typically regarded as an overuse injury rather than the result of acute trauma, with the cardinal symptom being pain around the patella and the anterior aspect of the knee during and after activity. Joint stiffness, crepitus, and popping may also be reported.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 The pain caused by this syndrome can be limiting to activity and affect quality of life, and may have associations with other knee pathologies. Those with PFPS experience abnormal loading at the joint that, over time, may result in degeneration of the cartilage and underlying bone, leading to osteoarthritis.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Is there a biomechanical link between patellofemoral pain and osteoarthritis? A narrative review.","id":"3434371","page":"1797-1808","type":"article-journal","volume":"46","issue":"12","author":[{"family":"Wyndow","given":"Narelle"},{"family":"Collins","given":"Natalie"},{"family":"Vicenzino","given":"Bill"},{"family":"Tucker","given":"Kylie"},{"family":"Crossley","given":"Kay"}],"issued":{"date-parts":[["2016","12"]]},"container-title":"Sports medicine (Auckland, N.Z.)","container-title-short":"Sports Med","journalAbbreviation":"Sports Med","DOI":"10.1007/s40279-016-0545-6","PMID":"27142536","citation-label":"3434371","Abstract":"The patellofemoral (PF) joint is the knee compartment most commonly affected by osteoarthritis (OA). Even mild PF OA is associated with considerable pain and functional limitations. Despite its prevalence and impact, little is understood of the etiology or structural and functional features of PF OA. The clinical symptoms of PF OA, such as anterior knee pain during stair ambulation and squatting, share many similarities with PF pain in adolescents and young adults. PF joint OA is most commonly diagnosed in people aged >40?years, many of whom report a history of PF pain. As such, there is growing evidence that PF pain and PF OA form a continuum of disease. This review explores the possible relationship between the presence of PF pain and the development of PF OA. We review the evidence for altered neuromotor control and biomechanical factors that may be associated with altered PF loading in people with PF pain and PF OA. In doing so, we highlight similarities and differences that may evolve along the continuum. By improving our understanding of the neuromotor and biomechanical links between PF pain and PF OA, we may highlight potential targets for new rehabilitation strategies.","CleanAbstract":"The patellofemoral (PF) joint is the knee compartment most commonly affected by osteoarthritis (OA). Even mild PF OA is associated with considerable pain and functional limitations. Despite its prevalence and impact, little is understood of the etiology or structural and functional features of PF OA. The clinical symptoms of PF OA, such as anterior knee pain during stair ambulation and squatting, share many similarities with PF pain in adolescents and young adults. PF joint OA is most commonly diagnosed in people aged >40?years, many of whom report a history of PF pain. As such, there is growing evidence that PF pain and PF OA form a continuum of disease. This review explores the possible relationship between the presence of PF pain and the development of PF OA. We review the evidence for altered neuromotor control and biomechanical factors that may be associated with altered PF loading in people with PF pain and PF OA. In doing so, we highlight similarities and differences that may evolve along the continuum. By improving our understanding of the neuromotor and biomechanical links between PF pain and PF OA, we may highlight potential targets for new rehabilitation strategies."}]6 This same abnormal loading and altered biomechanics make those with PFPS also at a possible increased risk for anterior cruciate ligament injury.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"High knee abduction moments are common risk factors for patellofemoral pain (PFP) and anterior cruciate ligament (ACL) injury in girls: is PFP itself a predictor for subsequent ACL injury?","id":"1129606","page":"118-122","type":"article-journal","volume":"49","issue":"2","author":[{"family":"Myer","given":"Gregory D"},{"family":"Ford","given":"Kevin R"},{"family":"Di Stasi","given":"Stephanie L"},{"family":"Foss","given":"Kim D Barber"},{"family":"Micheli","given":"Lyle J"},{"family":"Hewett","given":"Timothy E"}],"issued":{"date-parts":[["2015","1"]]},"container-title":"British Journal of Sports Medicine","container-title-short":"Br J Sports Med","journalAbbreviation":"Br J Sports Med","DOI":"10.1136/bjsports-2013-092536","PMID":"24687011","PMCID":"PMC4182160","citation-label":"1129606","Abstract":"BACKGROUND: Identifying risk factors for knee pain and anterior cruciate ligament (ACL) injury can be an important step in the injury prevention cycle. OBJECTIVE: We evaluated two unique prospective cohorts with similar populations and methodologies to compare the incidence rates and risk factors associated with patellofemoral pain (PFP) and ACL injury. METHODS: The 'PFP cohort' consisted of 240 middle and high school female athletes. They were evaluated by a physician and underwent anthropometric assessment, strength testing and three-dimensional landing biomechanical analyses prior to their basketball season. 145 of these athletes met inclusion for surveillance of incident (new) PFP by certified athletic trainers during their competitive season. The 'ACL cohort' included 205 high school female volleyball, soccer and basketball athletes who underwent the same anthropometric, strength and biomechanical assessment prior to their competitive season and were subsequently followed up for incidence of ACL injury. A one-way analysis of variance was used to evaluate potential group (incident PFP vs ACL injured) differences in anthropometrics, strength and landing biomechanics. Knee abduction moment (KAM) cut-scores that provided the maximal sensitivity and specificity for prediction of PFP or ACL injury risk were also compared between the cohorts. RESULTS: KAM during landing above 15.4?Nm was associated with a 6.8% risk to develop PFP compared to a 2.9% risk if below the PFP risk threshold in our sample. Likewise, a KAM above 25.3?Nm was associated with a 6.8% risk for subsequent ACL injury compared to a 0.4% risk if below the established ACL risk threshold. The ACL-injured athletes initiated landing with a greater knee abduction angle and a reduced hamstrings-to-quadriceps strength ratio relative to the incident PFP group. Also, when comparing across cohorts, the athletes who suffered ACL injury also had lower hamstring/quadriceps ratio than the players in the PFP sample (p< 0.05). CONCLUSIONS: In adolescent girls aged 13.3?years, >15?Nm of knee abduction load during landing is associated with greater likelihood of developing PFP. Also, in girls aged 16.1?years who land with >25?Nm of knee abduction load during landing are at increased risk for both PFP and ACL injury. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to .","CleanAbstract":"BACKGROUND: Identifying risk factors for knee pain and anterior cruciate ligament (ACL) injury can be an important step in the injury prevention cycle.OBJECTIVE: We evaluated two unique prospective cohorts with similar populations and methodologies to compare the incidence rates and risk factors associated with patellofemoral pain (PFP) and ACL injury.METHODS: The 'PFP cohort' consisted of 240 middle and high school female athletes. They were evaluated by a physician and underwent anthropometric assessment, strength testing and three-dimensional landing biomechanical analyses prior to their basketball season. 145 of these athletes met inclusion for surveillance of incident (new) PFP by certified athletic trainers during their competitive season. The 'ACL cohort' included 205 high school female volleyball, soccer and basketball athletes who underwent the same anthropometric, strength and biomechanical assessment prior to their competitive season and were subsequently followed up for incidence of ACL injury. A one-way analysis of variance was used to evaluate potential group (incident PFP vs ACL injured) differences in anthropometrics, strength and landing biomechanics. Knee abduction moment (KAM) cut-scores that provided the maximal sensitivity and specificity for prediction of PFP or ACL injury risk were also compared between the cohorts.RESULTS: KAM during landing above 15.4?Nm was associated with a 6.8% risk to develop PFP compared to a 2.9% risk if below the PFP risk threshold in our sample. Likewise, a KAM above 25.3?Nm was associated with a 6.8% risk for subsequent ACL injury compared to a 0.4% risk if below the established ACL risk threshold. The ACL-injured athletes initiated landing with a greater knee abduction angle and a reduced hamstrings-to-quadriceps strength ratio relative to the incident PFP group. Also, when comparing across cohorts, the athletes who suffered ACL injury also had lower hamstring/quadriceps ratio than the players in the PFP sample (pCONCLUSIONS: In adolescent girls aged 13.3?years, >15?Nm of knee abduction load during landing is associated with greater likelihood of developing PFP. Also, in girls aged 16.1?years who land with >25?Nm of knee abduction load during landing are at increased risk for both PFP and ACL injury.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to ."}]7 In addition, those suffering with PFPS have been found to have worsened dynamic standing balance, further placing them at risk for other injuries.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"The effects of muscle fatigue on dynamic standing balance in people with and without patellofemoral pain syndrome.","id":"4536568","page":"336-339","type":"article-journal","volume":"37","issue":"3","author":[{"family":"Negahban","given":"Hossein"},{"family":"Etemadi","given":"Malihe"},{"family":"Naghibi","given":"Saeed"},{"family":"Emrani","given":"Anita"},{"family":"Shaterzadeh Yazdi","given":"Mohammad Jafar"},{"family":"Salehi","given":"Reza"},{"family":"Moradi Bousari","given":"Aida"}],"issued":{"date-parts":[["2013","3"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2012.07.025","PMID":"22947999","citation-label":"4536568","Abstract":"The aim was to examine the effects of muscle fatigue of knee extensor and hip abductor muscles on dynamic standing balance of patients with patellofemoral pain syndrome (PFPS) compared to their healthy matched controls. Thirty participants (15 with PFPS, 15 controls) were recruited. Isolated muscle fatigue of two muscles was induced isokinetically in three separate sessions (one practice and two testing sessions) with a rest interval of at least 72h. In each testing session, fatigue protocol of only one muscle group was performed for the both legs with a rest time of 30min. After determining peak torque, participants were encouraged to perform continuous maximal concentric-eccentric contraction of the target muscle until the torque output dropped below 50% of peak value for 3 consecutive repetitions. Immediately after the completion of the fatigue protocol, balance testing of participants was undertaken during single leg standing using the Biodex stability system. Balance stability measures included the overall, anteroposterior and mediolateral stability indices (OSI, APSI and MLSI, respectively). Patients exhibited decreased balance stability in the sagittal plane (higher APSI) when compared to controls. Isolated muscle fatigue of the knee extensors and hip abductors reduced balance stability in both study groups. Fatigue of hip abductors was associated with greater balance instability (higher OSI and APSI) than fatigue of knee extensors. Copyright ? 2012 Elsevier B.V. All rights reserved.","CleanAbstract":"The aim was to examine the effects of muscle fatigue of knee extensor and hip abductor muscles on dynamic standing balance of patients with patellofemoral pain syndrome (PFPS) compared to their healthy matched controls. Thirty participants (15 with PFPS, 15 controls) were recruited. Isolated muscle fatigue of two muscles was induced isokinetically in three separate sessions (one practice and two testing sessions) with a rest interval of at least 72h. In each testing session, fatigue protocol of only one muscle group was performed for the both legs with a rest time of 30min. After determining peak torque, participants were encouraged to perform continuous maximal concentric-eccentric contraction of the target muscle until the torque output dropped below 50% of peak value for 3 consecutive repetitions. Immediately after the completion of the fatigue protocol, balance testing of participants was undertaken during single leg standing using the Biodex stability system. Balance stability measures included the overall, anteroposterior and mediolateral stability indices (OSI, APSI and MLSI, respectively). Patients exhibited decreased balance stability in the sagittal plane (higher APSI) when compared to controls. Isolated muscle fatigue of the knee extensors and hip abductors reduced balance stability in both study groups. Fatigue of hip abductors was associated with greater balance instability (higher OSI and APSI) than fatigue of knee extensors.Copyright ? 2012 Elsevier B.V. All rights reserved."}]8 These biomechanical and functional implications justify the need for prompt recognition and evidence-based management to rehabilitate and prevent recurrence of PFPS.EtiologyNo one precise cause of PFPS exists, it is instead commonly a consequence of a combination of biomechanical, structural, and soft tissue abnormalities that become exacerbated with overuse or repetitive loading. Although often unclear, a discussion of the proposed mechanisms behind PFPS is needed before moving forward to diagnosis and management recommendations. At the heart of the involved structures is the patella, a sesamoid bone anterior to the tibiofemoral joint that serves to increase the leverage of the quadriceps muscle. Resting in the trochlear groove of the femur, the patella is stabilized by the quadriceps and patellar tendons superiorly and inferiorly, and by retinacula laterally and medially.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors.","id":"4540589","page":"9","type":"article-journal","volume":"7","author":[{"family":"Waryasz","given":"Gregory R"},{"family":"McDermott","given":"Ann Y"}],"issued":{"date-parts":[["2008","6","26"]]},"container-title":"Dynamic medicine : DM","container-title-short":"Dyn Med","journalAbbreviation":"Dyn Med","DOI":"10.1186/1476-5918-7-9","PMID":"18582383","PMCID":"PMC2443365","citation-label":"4540589","Abstract":"BACKGROUND: Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS. METHODS: A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome. RESULTS: Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50-60% intensity. CONCLUSION: To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program.","CleanAbstract":"BACKGROUND: Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS.METHODS: A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome.RESULTS: Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50-60% intensity.CONCLUSION: To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program."}]9 The iliotibial (IT) band also attaches to the patella laterally.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"4330850","page":"2264-2274","type":"article-journal","volume":"22","issue":"10","author":[{"family":"Petersen","given":"Wolf"},{"family":"Ellermann","given":"Andree"},{"family":"G?sele-Koppenburg","given":"Andreas"},{"family":"Best","given":"Raymond"},{"family":"Rembitzki","given":"Ingo Volker"},{"family":"Brüggemann","given":"Gerd-Peter"},{"family":"Liebau","given":"Christian"}],"issued":{"date-parts":[["2014","10"]]},"container-title":"Knee Surgery, Sports Traumatology, Arthroscopy","container-title-short":"Knee Surg Sports Traumatol Arthrosc","journalAbbreviation":"Knee Surg Sports Traumatol Arthrosc","DOI":"10.1007/s00167-013-2759-6","PMID":"24221245","PMCID":"PMC4169618","citation-label":"4330850","Abstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes. LEVEL OF EVIDENCE: V.","CleanAbstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.LEVEL OF EVIDENCE: V."}]10 These structures are illustrated together in Appendix A, Figure 1. The quadriceps muscles act directly on the patella, with the vastus medialis obliquus (VMO), a component of the vastus medialis, receiving particular attention as an instigator of PFPS. The force vector of each quadriceps component on the patella can be seen in Appendix A, Figure 2. Structures that do not directly attach to the patella can still influence its tracking movement and endured contact pressures, such as the hamstring and gluteal musculature.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral Pain Syndrome: A Review and Guidelines for Treatment","id":"4540680","page":"2012-2018","type":"article-journal","volume":"60","issue":"7","author":[{"family":"Juhn","given":"Mark S."}],"issued":{"date-parts":[["1999","11","1"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","citation-label":"4540680"}]11Appreciation of the contribution each of these structures can make towards the development of PFPS begins with an understanding of their role in the alignment and kinematics of the patella and knee joint. Those with PFPS have been found to have several biomechanical deviations, which are thought to contribute to the development and persistence of this syndrome. An increased Q-angle and increased knee valgus remain commonly cited factors of causation due to the increased lateral force exerted on the patella in these conditions, although this may not be found in all cases.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"4330850","page":"2264-2274","type":"article-journal","volume":"22","issue":"10","author":[{"family":"Petersen","given":"Wolf"},{"family":"Ellermann","given":"Andree"},{"family":"G?sele-Koppenburg","given":"Andreas"},{"family":"Best","given":"Raymond"},{"family":"Rembitzki","given":"Ingo Volker"},{"family":"Brüggemann","given":"Gerd-Peter"},{"family":"Liebau","given":"Christian"}],"issued":{"date-parts":[["2014","10"]]},"container-title":"Knee Surgery, Sports Traumatology, Arthroscopy","container-title-short":"Knee Surg Sports Traumatol Arthrosc","journalAbbreviation":"Knee Surg Sports Traumatol Arthrosc","DOI":"10.1007/s00167-013-2759-6","PMID":"24221245","PMCID":"PMC4169618","citation-label":"4330850","Abstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes. LEVEL OF EVIDENCE: V.","CleanAbstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.LEVEL OF EVIDENCE: V."},{"title":"Greater Q angle may not be a risk factor of patellofemoral pain syndrome.","id":"4541357","page":"392-396","type":"article-journal","volume":"26","issue":"4","author":[{"family":"Park","given":"Sang-Kyoon"},{"family":"Stefanyshyn","given":"Darren J"}],"issued":{"date-parts":[["2011","5"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2010.11.015","PMID":"21177007","citation-label":"4541357","Abstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running. METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle. FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found. INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome. Copyright ? 2010 Elsevier Ltd. All rights reserved.","CleanAbstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running.METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle.FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found.INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome.Copyright ? 2010 Elsevier Ltd. All rights reserved."}]10,12 As described by Park and Stefanyshyn, “Q-angle is defined as the angle between the line connecting the anterior superior iliac spine (ASIS) to the center of the patella, and the extension of a line from the tibial tubercle to the same reference point on the patella” and is illustrated in Figure 1 of Appendix B.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Greater Q angle may not be a risk factor of patellofemoral pain syndrome.","id":"4541357","page":"392-396","type":"article-journal","volume":"26","issue":"4","author":[{"family":"Park","given":"Sang-Kyoon"},{"family":"Stefanyshyn","given":"Darren J"}],"issued":{"date-parts":[["2011","5"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2010.11.015","PMID":"21177007","citation-label":"4541357","Abstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running. METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle. FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found. INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome. Copyright ? 2010 Elsevier Ltd. All rights reserved.","CleanAbstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running.METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle.FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found.INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome.Copyright ? 2010 Elsevier Ltd. All rights reserved."}]12 Juhn cites several studies that find similar Q-angles in those without and without PFPS, and suggests that it may not be a sole contributor to the syndrome. This is further exemplified in the studies by Park and Stefanyshyn and by Liebensteiner et al. The first found that an increased Q-angle did not result in an increase in valgus moment at the knee while running, and the latter found no differences in frontal plane alignment in those with and without PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Greater Q angle may not be a risk factor of patellofemoral pain syndrome.","id":"4541357","page":"392-396","type":"article-journal","volume":"26","issue":"4","author":[{"family":"Park","given":"Sang-Kyoon"},{"family":"Stefanyshyn","given":"Darren J"}],"issued":{"date-parts":[["2011","5"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2010.11.015","PMID":"21177007","citation-label":"4541357","Abstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running. METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle. FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found. INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome. Copyright ? 2010 Elsevier Ltd. All rights reserved.","CleanAbstract":"BACKGROUND: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running.METHODS: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle.FINDINGS: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R?=0.2444, R=-0.4944, P=0.005) and impulse (R?=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R?=0.1842, R=-0.4292, P=0.016) and impulse (R?=0.2304, R=-0.4801, P=0.006) were found.INTERPRETATION: The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome.Copyright ? 2010 Elsevier Ltd. All rights reserved."},{"title":"Frontal plane leg alignment and muscular activity during maximum eccentric contractions in individuals with and without patellofemoral pain syndrome.","id":"4536550","page":"180-186","type":"article-journal","volume":"15","issue":"3","author":[{"family":"Liebensteiner","given":"M C"},{"family":"Szubski","given":"C"},{"family":"Raschner","given":"C"},{"family":"Krismer","given":"M"},{"family":"Burtscher","given":"M"},{"family":"Platzer","given":"H P"},{"family":"Deibl","given":"M"},{"family":"Dirnberger","given":"E"}],"issued":{"date-parts":[["2008","6"]]},"container-title":"The Knee","container-title-short":"Knee","journalAbbreviation":"Knee","DOI":"10.1016/j.knee.2008.01.009","PMID":"18295488","citation-label":"4536550","Abstract":"PURPOSE: The role of frontal plane tibiofemoral alignment in subjects with patellofemoral pain syndrome (PFPS) is controversial and rarely discussed in the literature. As well, little research has been done on the effects of the hamstrings muscles on PFPS. The aim of the current study was to determine whether, in individuals with PFPS, frontal plane tibiofemoral alignment or muscular activity of the index knee's crossing muscles is altered during maximum eccentric leg press exercise. METHODS: This cross-sectional study involved 19 patients with PFPS and 19 control subjects who were matched according to gender, age, and physical activity. During eccentric leg press action, frontal plane tibiofemoral alignment was assessed with a motion analysis system based on skin markers. Simultaneously, surface-electromyography was used to assess the activity levels of the relevant knee crossing muscles. To assess the activity under functional conditions, a leg press with a footplate having variable stability was used for barefoot testing. RESULTS: The PFPS subjects did not have significantly different frontal plane leg alignment compared to controls. On electromyography (EMG), PFPS patients had significantly lower levels of hamstring activity during eccentric leg exercise. The differences between the two groups (%; absolute differences normalized EMG) ranged from 20% (semitendinosus; stable footplate; p=0.017) to 21% (biceps femoris; unstable footplate; p=0.019) and 32% (semitendinosus; unstable footplate; p=0.002). CONCLUSIONS: PFPS is not linked to altered frontal plane leg alignment during eccentric leg pressing. However, PFPS is associated with eccentric under-activation of the hamstrings, which may be a compensatory strategy that maintains patellofemoral joint pressure within bearable levels.","CleanAbstract":"PURPOSE: The role of frontal plane tibiofemoral alignment in subjects with patellofemoral pain syndrome (PFPS) is controversial and rarely discussed in the literature. As well, little research has been done on the effects of the hamstrings muscles on PFPS. The aim of the current study was to determine whether, in individuals with PFPS, frontal plane tibiofemoral alignment or muscular activity of the index knee's crossing muscles is altered during maximum eccentric leg press exercise.METHODS: This cross-sectional study involved 19 patients with PFPS and 19 control subjects who were matched according to gender, age, and physical activity. During eccentric leg press action, frontal plane tibiofemoral alignment was assessed with a motion analysis system based on skin markers. Simultaneously, surface-electromyography was used to assess the activity levels of the relevant knee crossing muscles. To assess the activity under functional conditions, a leg press with a footplate having variable stability was used for barefoot testing.RESULTS: The PFPS subjects did not have significantly different frontal plane leg alignment compared to controls. On electromyography (EMG), PFPS patients had significantly lower levels of hamstring activity during eccentric leg exercise. The differences between the two groups (%; absolute differences normalized EMG) ranged from 20% (semitendinosus; stable footplate; p=0.017) to 21% (biceps femoris; unstable footplate; p=0.019) and 32% (semitendinosus; unstable footplate; p=0.002).CONCLUSIONS: PFPS is not linked to altered frontal plane leg alignment during eccentric leg pressing. However, PFPS is associated with eccentric under-activation of the hamstrings, which may be a compensatory strategy that maintains patellofemoral joint pressure within bearable levels."}]12,13 Therefore, although commonly used, this measure of alignment should be interpreted carefully and alongside other findings when determining a possible cause of PFPS.In terms of proximal kinematic differences, a systematic review by Neal et al. found that runners with PFPS demonstrate increased peak hip adduction, increased internal rotation of the femur, and increased contralateral hip drop compared to controls during runnning.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis.","id":"4426572","page":"69-82","type":"article-journal","volume":"45","author":[{"family":"Neal","given":"Bradley S"},{"family":"Barton","given":"Christian J"},{"family":"Gallie","given":"Rosa"},{"family":"O'Halloran","given":"Patrick"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2016","3"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2015.11.018","PMID":"26979886","citation-label":"4426572","Abstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms. Copyright ? 2015 Elsevier B.V. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms.Copyright ? 2015 Elsevier B.V. All rights reserved."}]14 Distally, those with PFPS have increased internal rotation of the tibia, and increased dorsiflexion and rearfoot eversion at heel strike.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"4330850","page":"2264-2274","type":"article-journal","volume":"22","issue":"10","author":[{"family":"Petersen","given":"Wolf"},{"family":"Ellermann","given":"Andree"},{"family":"G?sele-Koppenburg","given":"Andreas"},{"family":"Best","given":"Raymond"},{"family":"Rembitzki","given":"Ingo Volker"},{"family":"Brüggemann","given":"Gerd-Peter"},{"family":"Liebau","given":"Christian"}],"issued":{"date-parts":[["2014","10"]]},"container-title":"Knee Surgery, Sports Traumatology, Arthroscopy","container-title-short":"Knee Surg Sports Traumatol Arthrosc","journalAbbreviation":"Knee Surg Sports Traumatol Arthrosc","DOI":"10.1007/s00167-013-2759-6","PMID":"24221245","PMCID":"PMC4169618","citation-label":"4330850","Abstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes. LEVEL OF EVIDENCE: V.","CleanAbstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.LEVEL OF EVIDENCE: V."},{"title":"Kinematic gait characteristics associated with patellofemoral pain syndrome: a systematic review.","id":"4530918","page":"405-416","type":"article-journal","volume":"30","issue":"4","author":[{"family":"Barton","given":"Christian J"},{"family":"Levinger","given":"Pazit"},{"family":"Menz","given":"Hylton B"},{"family":"Webster","given":"Kate E"}],"issued":{"date-parts":[["2009","11"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2009.07.109","PMID":"19651515","citation-label":"4530918","Abstract":"Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the 'Quality Index' and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case-control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case-control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended.","CleanAbstract":"Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the 'Quality Index' and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case-control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case-control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended."}]10,15 These contribute to valgus positioning of the knee, suggesting a more dynamic lack of stabilization could be a cause of altered knee loads rather than a more static factor such as Q-angle.As mentioned previously, the function and balance of the VMO compared to other soft tissue forces acting on the patella has been a central component in proposed PFPS etiologies, yet this concept is surrounded by mixed research. Cowan et al. found that those with PFPS activate their vastus lateralis (VL) before the VMO during stair-stepping, a difference that controls did not demonstrate, thus supporting the idea that VMO dysfunction may contribute to PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome.","id":"4536493","page":"183-189","type":"article-journal","volume":"82","issue":"2","author":[{"family":"Cowan","given":"S M"},{"family":"Bennell","given":"K L"},{"family":"Hodges","given":"P W"},{"family":"Crossley","given":"K M"},{"family":"McConnell","given":"J"}],"issued":{"date-parts":[["2001","2"]]},"container-title":"Archives of Physical Medicine and Rehabilitation","container-title-short":"Arch Phys Med Rehabil","journalAbbreviation":"Arch Phys Med Rehabil","DOI":"10.1053/apmr.2001.19022","PMID":"11239308","citation-label":"4536493","Abstract":"OBJECTIVE: To determine whether electromyographic (EMG) onsets of vastus medialis obliquus (VMO) and vastus lateralis (VL) are altered in the presence of patellofemoral pain syndrome (PFPS) during the functional task of stair stepping. DESIGN: Cross-sectional. SETTING: University laboratory. PATIENTS: Thirty-three subjects with PFPS and 33 asymptomatic controls. INTERVENTIONS: Subjects ascended and descended a set of stairs-2 steps, each 20-cm high-at usual stair-stepping pace. EMG readings of VMO and VL taken on middle stair during step up (concentric contraction) and step down (eccentric contraction). MAIN OUTCOME MEASURES: Relative difference in onset of surface EMG activity of VMO compared with VL during a stair-stepping task. EMG onsets were determined by using a computer algorithm and were verified visually. RESULTS: In the PFPS population, the EMG onset of VL occurred before that of VMO in both the step up and step down phases of the stair-stepping task (p < .05). In contrast, no such differences occurred in the onsets of EMG activity of VMO and VL in either phase of the task for the control subjects. CONCLUSION: This finding supports the hypothesized relationship between changes in the timing of activity of the vastimuscles and PFPS. This finding provides theoretical rationale to support physiotherapy treatment commonly used in the management of PFPS.","CleanAbstract":"OBJECTIVE: To determine whether electromyographic (EMG) onsets of vastus medialis obliquus (VMO) and vastus lateralis (VL) are altered in the presence of patellofemoral pain syndrome (PFPS) during the functional task of stair stepping.DESIGN: Cross-sectional.SETTING: University laboratory.PATIENTS: Thirty-three subjects with PFPS and 33 asymptomatic controls.INTERVENTIONS: Subjects ascended and descended a set of stairs-2 steps, each 20-cm high-at usual stair-stepping pace. EMG readings of VMO and VL taken on middle stair during step up (concentric contraction) and step down (eccentric contraction).MAIN OUTCOME MEASURES: Relative difference in onset of surface EMG activity of VMO compared with VL during a stair-stepping task. EMG onsets were determined by using a computer algorithm and were verified visually.RESULTS: In the PFPS population, the EMG onset of VL occurred before that of VMO in both the step up and step down phases of the stair-stepping task (p CONCLUSION: This finding supports the hypothesized relationship between changes in the timing of activity of the vastimuscles and PFPS. This finding provides theoretical rationale to support physiotherapy treatment commonly used in the management of PFPS."}]16 However, a study by Cavazzuti et al. found no differences in timing between the VMO and VL in those with PFPS compared to those without.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Delayed onset of electromyographic activity of vastus medialis obliquus relative to vastus lateralis in subjects with patellofemoral pain syndrome.","id":"4536515","page":"290-295","type":"article-journal","volume":"32","issue":"3","author":[{"family":"Cavazzuti","given":"L"},{"family":"Merlo","given":"A"},{"family":"Orlandi","given":"F"},{"family":"Campanini","given":"I"}],"issued":{"date-parts":[["2010","7"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2010.06.025","PMID":"20727760","citation-label":"4536515","Abstract":"Patellofemoral Pain Syndrome (PFPS) is a common musculoskeletal complaint. The presence of a delay between vastus medialis obliquus (VMO) and vastus lateralis (VL) muscle onset has been suggested in the literature as a possible cause of PFPS, with poor agreement amongst authors on the value of the delay. In this study we computed the delay in the activation of VMO and VL in 15 PFPS patients and 20 age-matched controls (Ctrls) during the following tasks: sit to stand, stand to sit, squat, step up and step down. Activation instants were detected from surface EMG data by a double-threshold statistical detector. In order to compare the muscle activity throughout the task, we computed the delay between the instants in which the VMO and VL normalised envelopes reached subsequent normalised amplitude levels, until the envelope peak. In all investigated tasks but sit to stand, the onset delay was lower or equal then 0.02s, without group differences. Similarly, no differences between Ctrls and PFPS timing were found throughout all tasks, until the peak. Our results do not support the hypothesis that an onset delay between VMO and VL can be one of the causes of PFPS. Copyright ? 2010. Published by Elsevier B.V.","CleanAbstract":"Patellofemoral Pain Syndrome (PFPS) is a common musculoskeletal complaint. The presence of a delay between vastus medialis obliquus (VMO) and vastus lateralis (VL) muscle onset has been suggested in the literature as a possible cause of PFPS, with poor agreement amongst authors on the value of the delay. In this study we computed the delay in the activation of VMO and VL in 15 PFPS patients and 20 age-matched controls (Ctrls) during the following tasks: sit to stand, stand to sit, squat, step up and step down. Activation instants were detected from surface EMG data by a double-threshold statistical detector. In order to compare the muscle activity throughout the task, we computed the delay between the instants in which the VMO and VL normalised envelopes reached subsequent normalised amplitude levels, until the envelope peak. In all investigated tasks but sit to stand, the onset delay was lower or equal then 0.02s, without group differences. Similarly, no differences between Ctrls and PFPS timing were found throughout all tasks, until the peak. Our results do not support the hypothesis that an onset delay between VMO and VL can be one of the causes of PFPS.Copyright ? 2010. Published by Elsevier B.V."}]17 Beyond the matter of timing of muscle firing is that of imbalance, and Sawatsky et al. found that weakness in the VMO compared to the VL did not result in changes in pressure location, distribution, or contact area at the patellofemoral joint.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Changes in patellofemoral joint contact pressures caused by vastus medialis muscle weakness.","id":"1042017","page":"595-601","type":"article-journal","volume":"27","issue":"6","author":[{"family":"Sawatsky","given":"Andrew"},{"family":"Bourne","given":"Doug"},{"family":"Horisberger","given":"Monika"},{"family":"Jinha","given":"Azim"},{"family":"Herzog","given":"Walter"}],"issued":{"date-parts":[["2012","7"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2011.12.011","PMID":"22226076","citation-label":"1042017","Abstract":"BACKGROUND: Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.\n \n \nMETHODS: Experiments were performed using New Zealand white rabbits (mass 4.9-7.7 kg, n=12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.\n \n \nFINDINGS: Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.\n \n \nINTERPRETATION: We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.\n \n Copyright ? 2011 Elsevier Ltd. All rights reserved.","CleanAbstract":"BACKGROUND: Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.\n\n\nMETHODS: Experiments were performed using New Zealand white rabbits (mass 4.9-7.7 kg, n=12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.\n\n\nFINDINGS: Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.\n\n\nINTERPRETATION: We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.\n\nCopyright ? 2011 Elsevier Ltd. All rights reserved."}]3 Additionally, Besier et al. found that those with PFPS have “the same distribution of quadriceps forces as pain-free individuals during walking and running”. This study also found that those with PFPS showed increased quadriceps and hamstring co-contraction at heel-strike, implying that the hamstrings may have a role in PFPS by increasing contact forces.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls.","id":"4536546","page":"898-905","type":"article-journal","volume":"42","issue":"7","author":[{"family":"Besier","given":"Thor F"},{"family":"Fredericson","given":"Michael"},{"family":"Gold","given":"Garry E"},{"family":"Beaupré","given":"Gary S"},{"family":"Delp","given":"Scott L"}],"issued":{"date-parts":[["2009","5","11"]]},"container-title":"Journal of Biomechanics","container-title-short":"J Biomech","journalAbbreviation":"J Biomech","DOI":"10.1016/j.jbiomech.2009.01.032","PMID":"19268945","PMCID":"PMC2671570","citation-label":"4536546","Abstract":"One proposed mechanism of patellofemoral pain, increased stress in the joint, is dependent on forces generated by the quadriceps muscles. Describing causal relationships between muscle forces, tissue stresses, and pain is difficult due to the inability to directly measure these variables in vivo. The purpose of this study was to estimate quadriceps forces during walking and running in a group of male and female patients with patellofemoral pain (n = 27, 16 female; 11 male) and compare these to pain-free controls (n = 16, 8 female; 8 male). Subjects walked and ran at self-selected speeds in a gait laboratory. Lower limb kinematics and electromyography (EMG) data were input to an EMG-driven musculoskeletal model of the knee, which was scaled and calibrated to each individual to estimate forces in 10 muscles surrounding the joint. Compared to controls, the patellofemoral pain group had greater co-contraction of quadriceps and hamstrings (p = 0.025) and greater normalized muscle forces during walking, even though the net knee moment was similar between groups. Muscle forces during running were similar between groups, but the net knee extension moment was less in the patellofemoral pain group compared to controls. Females displayed 30-50% greater normalized hamstring and gastrocnemius muscle forces during both walking and running compared to males (p< 0.05). These results suggest that some patellofemoral pain patients might experience greater joint contact forces and joint stresses than pain-free subjects. The muscle force data are available as supplementary material.","CleanAbstract":"One proposed mechanism of patellofemoral pain, increased stress in the joint, is dependent on forces generated by the quadriceps muscles. Describing causal relationships between muscle forces, tissue stresses, and pain is difficult due to the inability to directly measure these variables in vivo. The purpose of this study was to estimate quadriceps forces during walking and running in a group of male and female patients with patellofemoral pain (n = 27, 16 female; 11 male) and compare these to pain-free controls (n = 16, 8 female; 8 male). Subjects walked and ran at self-selected speeds in a gait laboratory. Lower limb kinematics and electromyography (EMG) data were input to an EMG-driven musculoskeletal model of the knee, which was scaled and calibrated to each individual to estimate forces in 10 muscles surrounding the joint. Compared to controls, the patellofemoral pain group had greater co-contraction of quadriceps and hamstrings (p = 0.025) and greater normalized muscle forces during walking, even though the net knee moment was similar between groups. Muscle forces during running were similar between groups, but the net knee extension moment was less in the patellofemoral pain group compared to controls. Females displayed 30-50% greater normalized hamstring and gastrocnemius muscle forces during both walking and running compared to males (p< 0.05). These results suggest that some patellofemoral pain patients might experience greater joint contact forces and joint stresses than pain-free subjects. The muscle force data are available as supplementary material."}]18 Patil et al. similarly found no differences in VMO to VL activation, but did see increased lateral hamstring activation in those with PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"An electromyographic exploratory study comparing the difference in the onset of hamstring and quadriceps contraction in patients with anterior knee pain.","id":"4536533","page":"329-332","type":"article-journal","volume":"18","issue":"5","author":[{"family":"Patil","given":"Sunit"},{"family":"Dixon","given":"John"},{"family":"White","given":"Lisa C"},{"family":"Jones","given":"Alex P"},{"family":"Hui","given":"Anthony C W"}],"issued":{"date-parts":[["2011","10"]]},"container-title":"The Knee","container-title-short":"Knee","journalAbbreviation":"Knee","DOI":"10.1016/j.knee.2010.07.007","PMID":"20724165","citation-label":"4536533","Abstract":"Idiopathic anterior knee pain in teenagers and young adults is a common condition. Patellar maltracking has been considered as a causative factor. The aim of our study was to investigate whether there was a difference in the timing of electromyographic (EMG) activity in the medial and lateral hamstring and quadriceps muscles of patients with anterior knee pain compared to asymptomatic control participants. This was a cross sectional observational study measuring EMG activation patterns. Two groups of participants were tested, one patient (mean age 15 years, n = 20) and one asymptomatic control (mean age 16 years, n = 17). Surface EMG (sampling rate 1000 Hz) was recorded from vastus medialis obliqus, vastus lateralis, and the medial and lateral hamstrings during three repetitions of maximal voluntary isometric contractions. The relative timing of the medial and lateral quadriceps and hamstrings was evaluated. The mean (95% confidence interval) difference between the groups in the lateral-medial hamstring onset timing was 53.8(1.9 to 105.6)ms during the maximal contraction. An independent t test showed that this difference was statistically significant (p = 0.043). The differences between the groups in the relative VMO to VL onset did not reach statistical significance. The results of this study suggest that the lateral hamstrings contract significantly earlier in patients with AKP compared to healthy controls for this small cohort. This altered activation pattern could produce external rotation of the tibia on the femur and cause lateral patella tracking. Copyright ? 2010 Elsevier B.V. All rights reserved.","CleanAbstract":"Idiopathic anterior knee pain in teenagers and young adults is a common condition. Patellar maltracking has been considered as a causative factor. The aim of our study was to investigate whether there was a difference in the timing of electromyographic (EMG) activity in the medial and lateral hamstring and quadriceps muscles of patients with anterior knee pain compared to asymptomatic control participants. This was a cross sectional observational study measuring EMG activation patterns. Two groups of participants were tested, one patient (mean age 15 years, n = 20) and one asymptomatic control (mean age 16 years, n = 17). Surface EMG (sampling rate 1000 Hz) was recorded from vastus medialis obliqus, vastus lateralis, and the medial and lateral hamstrings during three repetitions of maximal voluntary isometric contractions. The relative timing of the medial and lateral quadriceps and hamstrings was evaluated. The mean (95% confidence interval) difference between the groups in the lateral-medial hamstring onset timing was 53.8(1.9 to 105.6)ms during the maximal contraction. An independent t test showed that this difference was statistically significant (p = 0.043). The differences between the groups in the relative VMO to VL onset did not reach statistical significance. The results of this study suggest that the lateral hamstrings contract significantly earlier in patients with AKP compared to healthy controls for this small cohort. This altered activation pattern could produce external rotation of the tibia on the femur and cause lateral patella tracking.Copyright ? 2010 Elsevier B.V. All rights reserved."}]19 In all, these studies suggest that attention should be paid to all forces that act on the knee, not solely the VMO. DiagnosisUnsurprising given the complexity surrounding the cause of PFPS, diagnosis is primarily a diagnosis of exclusion. However, there are components for examination that are recommended for PFPS, most of which involve assessment of the factors previously discussed as possible contributors to the development of PFPS. While gathering the patient’s history, if they report aforementioned symptoms or are a member of the typically affected populations, this will be the first finding supporting PFPS, particularly if the onset was after an increase in activity type, frequency, or duration. However, since it presents so similarly to other knee pathologies, objective examination must be comprehensive.Palpation of the patella may be useful in ruling out PFPS in that swelling or tenderness of the patella itself are not typical of PFPS and therefore may be indicative of other pathologies. Joint noise, such as crepitus or popping, is often seen yet is not specific to PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 Patellar position and mobility should be thoroughly addressed, for which there are several means. Glide describes the lateral and medial displacement of the patella and can be observed by comparing the midpoint of the patella in relation to the femoral epicondyles, which can be objectively recorded by measuring the distance between the midpoint and each epicondyle. This can be observed both at rest and during contraction of the quadriceps, noting any change in position. Lateral glide is common in PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"1488197","page":"379-398","type":"article-journal","volume":"29","issue":"3","author":[{"family":"Collado","given":"Hervé"},{"family":"Fredericson","given":"Michael"}],"issued":{"date-parts":[["2010","7"]]},"container-title":"Clinics in sports medicine","container-title-short":"Clin Sports Med","journalAbbreviation":"Clin Sports Med","DOI":"10.1016/j.csm.2010.03.012","PMID":"20610028","citation-label":"1488197","Abstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved."}]20 Patellar tilt describes the height of the medial and lateral borders relative to the surface of the femur. An illustration of examples of both glide and tilt can be seen in Appendix C, Figure 1. The patellar tilt test was shown to have a strong positive likelihood ratio for ruling in PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Clinical test for diagnosis of patellofemoral pain syndrome: Systematic review with meta-analysis.","id":"3409551","page":"54-59","type":"article-journal","volume":"14","issue":"1","author":[{"family":"Nunes","given":"Guilherme S"},{"family":"Stapait","given":"Eduardo Luiz"},{"family":"Kirsten","given":"Michel Hors"},{"family":"de Noronha","given":"Marcos"},{"family":"Santos","given":"Gilmar Moraes"}],"issued":{"date-parts":[["2013","2"]]},"container-title":"Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine","container-title-short":"Phys Ther Sport","journalAbbreviation":"Phys Ther Sport","DOI":"10.1016/j.ptsp.2012.11.003","PMID":"23232069","citation-label":"3409551","Abstract":"The high incidence and diversity of factors attributed to the etiology of patellofemoral pain syndrome (PFPS) makes the diagnosis of this problem somewhat complex and susceptible to misinterpretation. Currently, there is not a defined set of procedures considered as ideal to diagnose PFPS. To investigate the diagnostic accuracy of clinical and functional tests used to diagnose PFPS through a systematic review. We searched relevant studies in the databases Medline, CINAHL, SPORTDiscus and Embase. The QUADAS score was used to assess the methodological quality of the eligible studies. We analyzed data that indicated the diagnostic properties of tests, such as sensibility, specificity, positive (LR+) and negative (LR-) likelihood ratio, and predictive values. The search identified 16,169 potential studies and five studies met the eligibility criteria. The 5 studies analyzed 25 tests intending to accurately diagnose PFPS. Two tests were analyzed in two studies and were possible to perform a meta-analysis. Within the five studies included, one study had high methodological quality, two studies had good methodological quality and two studies had low methodological quality. Two tests, the patellar tilt (LR+?=?5.4 and LR-?=?0.6) and squatting (LR+?=?1.8 and LR-?=?0.2), had values that show a trend for the diagnosis of PFPS (LR+ >5.0 and LR- < 0.2), however their values do not represent clear evidence regarding diagnostic properties as suggested in the literature (LR+ >10 and LR- < 0.1). Future diagnostic studies should focus on the sample homogeneity and standardization of tests analyzed so future systematic reviews can determine with more certainty the accuracy of the tests for diagnosis of PFPS. Copyright ? 2012 Elsevier Ltd. All rights reserved.","CleanAbstract":"The high incidence and diversity of factors attributed to the etiology of patellofemoral pain syndrome (PFPS) makes the diagnosis of this problem somewhat complex and susceptible to misinterpretation. Currently, there is not a defined set of procedures considered as ideal to diagnose PFPS. To investigate the diagnostic accuracy of clinical and functional tests used to diagnose PFPS through a systematic review. We searched relevant studies in the databases Medline, CINAHL, SPORTDiscus and Embase. The QUADAS score was used to assess the methodological quality of the eligible studies. We analyzed data that indicated the diagnostic properties of tests, such as sensibility, specificity, positive (LR+) and negative (LR-) likelihood ratio, and predictive values. The search identified 16,169 potential studies and five studies met the eligibility criteria. The 5 studies analyzed 25 tests intending to accurately diagnose PFPS. Two tests were analyzed in two studies and were possible to perform a meta-analysis. Within the five studies included, one study had high methodological quality, two studies had good methodological quality and two studies had low methodological quality. Two tests, the patellar tilt (LR+?=?5.4 and LR-?=?0.6) and squatting (LR+?=?1.8 and LR-?=?0.2), had values that show a trend for the diagnosis of PFPS (LR+ >5.0 and LR- 10 and LR- Copyright ? 2012 Elsevier Ltd. All rights reserved."}]21 This test is performed on a passively extended knee, holding the patella with the thumb and index finger, and simultaneously compressing the medial border and lifting the lateral border. A positive result is when the lateral border cannot be lifted to achieve a normal orientation, indicating tightness in the lateral structures that may be interfering with normal patellofemoral mechanics.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 An illustration of the performance of this test can be seen in Appendix C, Figure 2.An assessment of alignment is recommended throughout the literature. Statically, this can be done by assessing Q-angle as previously described. However, research regarding this measure is inconsistent and instead favors evaluation of dynamic alignment. Collado and Fredericson recommend this be done during stepping up and down from a stool or during single-leg squats. During these motions, the therapist should not only observe the movement and tracking of the patella, but also make note of any particular movement patterns. Patterns such as knee abduction or poor hip control demonstrated by hip adduction and contralateral hip drop are associated with PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"1488197","page":"379-398","type":"article-journal","volume":"29","issue":"3","author":[{"family":"Collado","given":"Hervé"},{"family":"Fredericson","given":"Michael"}],"issued":{"date-parts":[["2010","7"]]},"container-title":"Clinics in sports medicine","container-title-short":"Clin Sports Med","journalAbbreviation":"Clin Sports Med","DOI":"10.1016/j.csm.2010.03.012","PMID":"20610028","citation-label":"1488197","Abstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved."}]20 Abnormal tracking of the patella during these activities or during seated knee extension may present in the form of the “J” sign, in which the patella swiftly moves laterally as the knee moves from flexion to terminal extension instead of moving straight.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"1488197","page":"379-398","type":"article-journal","volume":"29","issue":"3","author":[{"family":"Collado","given":"Hervé"},{"family":"Fredericson","given":"Michael"}],"issued":{"date-parts":[["2010","7"]]},"container-title":"Clinics in sports medicine","container-title-short":"Clin Sports Med","journalAbbreviation":"Clin Sports Med","DOI":"10.1016/j.csm.2010.03.012","PMID":"20610028","citation-label":"1488197","Abstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved."},{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5,20 This maltracking is a sign of increased lateral tension, and an illustration of this movement can be seen in Appendix C, Figure 3.Manual muscle testing and range of motion assessment of the lower extremity should be included as a routine part of assessment. In particular, weakness of the quadriceps and the gluteal muscles is associated with PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."},{"title":"Patellofemoral pain syndrome.","id":"4330850","page":"2264-2274","type":"article-journal","volume":"22","issue":"10","author":[{"family":"Petersen","given":"Wolf"},{"family":"Ellermann","given":"Andree"},{"family":"G?sele-Koppenburg","given":"Andreas"},{"family":"Best","given":"Raymond"},{"family":"Rembitzki","given":"Ingo Volker"},{"family":"Brüggemann","given":"Gerd-Peter"},{"family":"Liebau","given":"Christian"}],"issued":{"date-parts":[["2014","10"]]},"container-title":"Knee Surgery, Sports Traumatology, Arthroscopy","container-title-short":"Knee Surg Sports Traumatol Arthrosc","journalAbbreviation":"Knee Surg Sports Traumatol Arthrosc","DOI":"10.1007/s00167-013-2759-6","PMID":"24221245","PMCID":"PMC4169618","citation-label":"4330850","Abstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes. LEVEL OF EVIDENCE: V.","CleanAbstract":"UNLABELLED: The patellofemoral pain syndrome (PFPS) is a possible cause for anterior knee pain, which predominantly affects young female patients without any structural changes such as increased Q-angle or significant chondral damage. This literature review has shown that PFPS development is probably multifactorial with various functional disorders of the lower extremity. Biomechanical studies described patellar maltracking and dynamic valgus in PFPS patients (functional malalignment). Causes for the dynamic valgus may be decreased strength of the hip abductors or abnormal rear-foot eversion with pes pronatus valgus. PFPS is further associated with vastus medialis/vastus lateralis dysbalance, hamstring tightness or iliotibial tract tightness. The literature provides evidence for a multimodal non-operative therapy concept with short-term use of NSAIDs, short-term use of a medially directed tape and exercise programmes with the inclusion of the lower extremity, and hip and trunk muscles. There is also evidence for the use of patellar braces and foot orthosis. A randomized controlled trial has shown that arthroscopy is not the treatment of choice for treatment of PFPS without any structural changes. Patients with anterior knee pain have to be examined carefully with regard to functional causes for a PFPS. The treatment of PFPS patients is non-operative and should address the functional causes.LEVEL OF EVIDENCE: V."}]5,10 Also, reduced flexibility in the quadriceps, hamstrings, and IT band are frequently seen in PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5Lastly, an analysis of gait, as well as running if applicable for the patient, is a beneficial component of the examination for this population. Similar to the need to assess dynamic alignment with a slow stepping motion, alignment of the knee should be observed during functional activity. In addition, parameters of the patient’s gait and run should also be noted. Barton et al. found that those with PFPS exhibited an increase in support time, decrease in cadence and decrease in stride length during running and walking.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Kinematic gait characteristics associated with patellofemoral pain syndrome: a systematic review.","id":"4530918","page":"405-416","type":"article-journal","volume":"30","issue":"4","author":[{"family":"Barton","given":"Christian J"},{"family":"Levinger","given":"Pazit"},{"family":"Menz","given":"Hylton B"},{"family":"Webster","given":"Kate E"}],"issued":{"date-parts":[["2009","11"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2009.07.109","PMID":"19651515","citation-label":"4530918","Abstract":"Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the 'Quality Index' and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case-control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case-control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended.","CleanAbstract":"Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the 'Quality Index' and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case-control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case-control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended."}]15 Deviations in walking or running form and manipulation of these parameters could influence the onset of pain in the affected individual.Imaging is generally not indicated in this population for diagnosis of PFPS, but may be useful to rule out other pathologies. For instance, if the patient reports recent trauma or surgery, radiography may be warranted. Radiographs can detect the presence of fractures, osteoarthritis, physeal damage, osteochondritis dissecans, and bone tumors. Also, magnetic resonance imaging (MRI) may be used to assess for stress fractures, soft tissue tears, or cartilage damage.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 Many other pathologies may present as pain in the anterior region of the knee with an insidious onset, so familiarity with these will aid in the exclusion process often required to reach a diagnosis of PFPS. The table in Appendix B, Figure 4 provides an overview of these pathologies and defining characteristics that may separate their presentation from that of PFPS. In summary, PFPS typically does not involve joint effusion or swelling, a characteristic that separates it from several other conditions, including prepatellar bursitis, osteochondritis dissecans, cartilage injury, and chondromalacia patellae.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 As discussed previously, some pathologies may have radiographic findings if imaging is performed, whereas PFPS would not demonstrate any findings on imaging other than displaying malalignment of the patella more readily. Specific location of tenderness can also help to differentiate PFPS, with which tenderness is “behind or around the patella”, medial, or lateral retinaculum. Tenderness more localized over the joint line would be more characteristic with meniscal injury, throughout the quadriceps and patellar tendons more in line with a tendinopathy, and along the femoral condyles could mean collateral ligament damage. If the patient is an adolescent, consideration should be given to Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease, both of which are found in this age group and present with pain at the proximal and distal attachments of the patellar tendon respectively. Lastly, screening of the lumbar spine and hip is recommended, as these sites could refer to the knee.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 InterventionsOnce a therapist has reached the conclusion that they are seeing PFPS in the patient, many of the recommended interventions target the proposed etiologies and deficits possibly found during the assessment. The first approach to managing this syndrome is activity modification. While relative rest is indicated due to this condition’s connection to overuse, a therapist must have more developed, individualized recommendations than simply telling the patient to stop doing all activity. For runners, this could mean recommend that they decrease the distance they run, and how many times a week they run. They also may need to find another form of aerobic activity to maintain their cardiorespiratory endurance while decreasing the loading on their knee, which could include cycling, swimming, or elliptical use. If there is a specific exercise they do, such as squats or lunges, that provokes symptoms, help the patient find alternative exercises that target what they are trying to achieve with the provoking exercise.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5 It is also recommended that patients do not over-exert themselves during their exercise. Neal et al. found that the running biomechanics characteristic of those with PFPS, such as the aforementioned hip adduction and contralateral hip drop, also become evident in healthy individuals as they fatigued.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis.","id":"4426572","page":"69-82","type":"article-journal","volume":"45","author":[{"family":"Neal","given":"Bradley S"},{"family":"Barton","given":"Christian J"},{"family":"Gallie","given":"Rosa"},{"family":"O'Halloran","given":"Patrick"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2016","3"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2015.11.018","PMID":"26979886","citation-label":"4426572","Abstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms. Copyright ? 2015 Elsevier B.V. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms.Copyright ? 2015 Elsevier B.V. All rights reserved."}]14 Therefore, even if the patient works to improve their running mechanics, continuing to exercise in a fatigued state could compromise their form and increase the chance of recurrence. In addition to addressing the factors of running distance or duration, modification of their mechanics may also be beneficial. Neal et al. found that retraining running mechanics, with a specific focus on reducing hip adduction, resulted in significantly reduced pain and improved function in runners with PFPS. To facilitate this in the clinic, the authors recommended the use of video or a mirror in front of a treadmill to give the patient visual feedback.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis.","id":"4426572","page":"69-82","type":"article-journal","volume":"45","author":[{"family":"Neal","given":"Bradley S"},{"family":"Barton","given":"Christian J"},{"family":"Gallie","given":"Rosa"},{"family":"O'Halloran","given":"Patrick"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2016","3"]]},"container-title":"Gait & Posture","container-title-short":"Gait Posture","journalAbbreviation":"Gait Posture","DOI":"10.1016/j.gaitpost.2015.11.018","PMID":"26979886","citation-label":"4426572","Abstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms. Copyright ? 2015 Elsevier B.V. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms.Copyright ? 2015 Elsevier B.V. All rights reserved."}]14 There is also evidence supporting that an increased cadence can result in less stress on the patellofemoral joint, with Lenhart et al. finding that a 10% increase in step rate resulted in a 10.4% decrease in the average patellar contact pressure.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Influence of step rate and quadriceps load distribution on patellofemoral cartilage contact pressures during running.","id":"4536535","page":"2871-2878","type":"article-journal","volume":"48","issue":"11","author":[{"family":"Lenhart","given":"Rachel L"},{"family":"Smith","given":"Colin R"},{"family":"Vignos","given":"Michael F"},{"family":"Kaiser","given":"Jarred"},{"family":"Heiderscheit","given":"Bryan C"},{"family":"Thelen","given":"Darryl G"}],"issued":{"date-parts":[["2015","8","20"]]},"container-title":"Journal of Biomechanics","container-title-short":"J Biomech","journalAbbreviation":"J Biomech","DOI":"10.1016/j.jbiomech.2015.04.036","PMID":"26070646","PMCID":"PMC4536167","citation-label":"4536535","Abstract":"Interventions used to treat patellofemoral pain in runners are often designed to alter patellofemoral mechanics. This study used a computational model to investigate the influence of two interventions, step rate manipulation and quadriceps strengthening, on patellofemoral contact pressures during running. Running mechanics were analyzed using a lower extremity musculoskeletal model that included a knee with six degree-of-freedom tibiofemoral and patellofemoral joints. An elastic foundation model was used to compute articular contact pressures. The lower extremity model was scaled to anthropometric dimensions of 22 healthy adults, who ran on an instrumented treadmill at 90%, 100% and 110% of their preferred step rate. Numerical optimization was then used to predict the muscle forces, secondary tibiofemoral kinematics and all patellofemoral kinematics that would generate the measured primary hip, knee and ankle joint accelerations. Mean and peak patella contact pressures reached 5.0 and 9.7MPa during the midstance phase of running. Increasing step rate by 10% significantly reduced mean contact pressures by 10.4% and contact area by 7.4%, but had small effects on lateral patellar translation and tilt. Enhancing vastus medialis strength did not substantially affect pressure magnitudes or lateral patellar translation, but did shift contact pressure medially toward the patellar median ridge. Thus, the model suggests that step rate tends to primarily modulate the magnitude of contact pressure and contact area, while vastus medialis strengthening has the potential to alter mediolateral pressure locations. These results are relevant to consider in the design of interventions used to prevent or treat patellofemoral pain in runners. Copyright ? 2015 Elsevier Ltd. All rights reserved.","CleanAbstract":"Interventions used to treat patellofemoral pain in runners are often designed to alter patellofemoral mechanics. This study used a computational model to investigate the influence of two interventions, step rate manipulation and quadriceps strengthening, on patellofemoral contact pressures during running. Running mechanics were analyzed using a lower extremity musculoskeletal model that included a knee with six degree-of-freedom tibiofemoral and patellofemoral joints. An elastic foundation model was used to compute articular contact pressures. The lower extremity model was scaled to anthropometric dimensions of 22 healthy adults, who ran on an instrumented treadmill at 90%, 100% and 110% of their preferred step rate. Numerical optimization was then used to predict the muscle forces, secondary tibiofemoral kinematics and all patellofemoral kinematics that would generate the measured primary hip, knee and ankle joint accelerations. Mean and peak patella contact pressures reached 5.0 and 9.7MPa during the midstance phase of running. Increasing step rate by 10% significantly reduced mean contact pressures by 10.4% and contact area by 7.4%, but had small effects on lateral patellar translation and tilt. Enhancing vastus medialis strength did not substantially affect pressure magnitudes or lateral patellar translation, but did shift contact pressure medially toward the patellar median ridge. Thus, the model suggests that step rate tends to primarily modulate the magnitude of contact pressure and contact area, while vastus medialis strengthening has the potential to alter mediolateral pressure locations. These results are relevant to consider in the design of interventions used to prevent or treat patellofemoral pain in runners.Copyright ? 2015 Elsevier Ltd. All rights reserved."}]22 The use of therapeutic exercise is at the forefront of treatment for PFPS. Strengthening of the quadriceps is the most commonly used intervention, and has been shown to have positive results.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"A review of the management of patellofemoral pain syndrome.","id":"4538200","page":"19-28","type":"article-journal","volume":"41","issue":"3","author":[{"family":"Rixe","given":"Jeffrey A"},{"family":"Glick","given":"Joshua E"},{"family":"Brady","given":"Jodi"},{"family":"Olympia","given":"Robert P"}],"issued":{"date-parts":[["2013","9"]]},"container-title":"The Physician and sportsmedicine","container-title-short":"Phys Sportsmed","journalAbbreviation":"Phys Sportsmed","DOI":"10.3810/psm.2013.09.2023","PMID":"24113699","citation-label":"4538200","Abstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS. METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years. RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS. CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.","CleanAbstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS."}]23 Attempts to selectively target the VMO in strengthening are often incorporated as well due to its perceived role in PFPS. The recommendation for how to accomplish this focus on the VMO is generally to include hip adduction into knee extension exercises. Choi et al. studied an isometric knee extension with hip adduction exercise and its effects on the VMO and VL, and found that this exercise did not selectively strengthen the VMO but did result in earlier VMO activation, lessening the onset difference between the VMO and VL.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"The effects of an isometric knee extension with hip adduction (KEWHA) exercise on selective VMO muscle strengthening.","id":"4536534","page":"1011-1016","type":"article-journal","volume":"21","issue":"6","author":[{"family":"Choi","given":"Boram"},{"family":"Kim","given":"Minhee"},{"family":"Jeon","given":"Hye-Seon"}],"issued":{"date-parts":[["2011","12"]]},"container-title":"Journal of Electromyography and Kinesiology","container-title-short":"J Electromyogr Kinesiol","journalAbbreviation":"J Electromyogr Kinesiol","DOI":"10.1016/j.jelekin.2011.08.008","PMID":"21925899","citation-label":"4536534","Abstract":"We investigated the effects of four weeks of training using a knee extension with hip adduction (KEWHA) exercise in asymptomatic participants. In addition, we compared different methods of electromyographic (EMG) onset-time detection. Eighteen participants who achieved earlier activation of the vastus lateralis (VL) muscle compared to that of the vastus medialis obliquus (VMO) muscle performed the isometric KEWHA exercise in the sitting position for four weeks. A 15° hip adduction was added to the existing knee extension in the KEWHA exercise. EMG onset times were detected using a computer-analyzed system and evaluated using two methods in which the thresholds for activity onset were set at two and three standard deviations (SDs) of the mean baseline activity. No significant difference in the EMG onset-time for the VMO muscle was observed compared to that of the VL muscle between the pre- and post-tests (p>0.05) when data at 2SDs of the mean baseline activity were analyzed. However, a significant difference in the onset times for the VMO muscle and VL muscle was found between the pre- and post-tests (p< 0.05) when data at 3SDs of the mean baseline activity were analyzed. In addition, less variation was observed in data analyzed at 3SDs compared to that of the data at 2SDs. The normalized VMO:VL muscle ratio was not significantly different between the pre- and post-tests. These findings show that the KEWHA exercise may decrease the difference between the onset times of VMO and VL muscles. In addition, we suggest that task-specific EMG onset-time detection methods are required to minimize variations in the data obtained during the recording of muscle activation. Copyright ?? 2011 Elsevier Ltd. All rights reserved.","CleanAbstract":"We investigated the effects of four weeks of training using a knee extension with hip adduction (KEWHA) exercise in asymptomatic participants. In addition, we compared different methods of electromyographic (EMG) onset-time detection. Eighteen participants who achieved earlier activation of the vastus lateralis (VL) muscle compared to that of the vastus medialis obliquus (VMO) muscle performed the isometric KEWHA exercise in the sitting position for four weeks. A 15° hip adduction was added to the existing knee extension in the KEWHA exercise. EMG onset times were detected using a computer-analyzed system and evaluated using two methods in which the thresholds for activity onset were set at two and three standard deviations (SDs) of the mean baseline activity. No significant difference in the EMG onset-time for the VMO muscle was observed compared to that of the VL muscle between the pre- and post-tests (p>0.05) when data at 2SDs of the mean baseline activity were analyzed. However, a significant difference in the onset times for the VMO muscle and VL muscle was found between the pre- and post-tests (pCopyright ?? 2011 Elsevier Ltd. All rights reserved."}]24 So while this does not support that this exercise can provide targeted strengthening of the VMO, it may be useful from a neuromuscular standpoint to achieve improve muscular control of the quadriceps components. With similar intent, Peng et al. looked at the use of isometric hip adduction during a leg press exercise, and found that the addition of hip adduction did not increase the activation of the VMO throughout the full range of motion of the exercise. However, they found that the VMO to VL activation ratio was highest in the last 45 degrees of knee extension with hip adduction, leading the authors to recommend that this exercise would be most beneficial if performed as a “semi-squat” rather than having the patient go through a full range of motion.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Muscle activation of vastus medialis obliquus and vastus lateralis during a dynamic leg press exercise with and without isometric hip adduction.","id":"4536576","page":"44-49","type":"article-journal","volume":"14","issue":"1","author":[{"family":"Peng","given":"Hsien-Te"},{"family":"Kernozek","given":"Thomas W"},{"family":"Song","given":"Chen-Yi"}],"issued":{"date-parts":[["2013","2"]]},"container-title":"Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine","container-title-short":"Phys Ther Sport","journalAbbreviation":"Phys Ther Sport","DOI":"10.1016/j.ptsp.2012.02.006","PMID":"23312731","citation-label":"4536576","Abstract":"OBJECTIVES: To investigate the effects of submaximal and vigorous isometric hip adduction on the vastus medialis obliquus (VMO) and vastus lateralis (VL) activity during the leg press exercise from 90° of knee flexion until full extension. DESIGN: Experimental. SETTING: University biomechanics laboratory. PARTICIPANTS: Ten healthy male college students. MAIN OUTCOME MEASURES: Electromyographic (EMG) activation of VMO, VL and hip adductor longus (HAL) of the dominant leg were recorded during double leg press (LP), leg press with submaximal isometric hip adduction force (LP+), and leg press with vigorous isometric hip adduction force (LP++). The VMO, VL muscle activation, as well as the VMO/VL ratio between different leg press exercises were analyzed by MANOVA over concentric and eccentric phases, and in 15° increments of knee flexion motion. The effect size was calculated. RESULTS: Neither LP+ nor LP++ changed the overall VMO-VL activation patterns. Specific to knee angle, however, small to medium effect size was shown with incorporation of isometric hip adduction to the leg press exercise for VMO/VL ratio. CONCLUSION: Targeted training using the leg press exercise to the last 45° of knee extension/flexion with vigorous hip adduction may be useful in promoting a greater VMO/VL ratio. Copyright ? 2012 Elsevier Ltd. All rights reserved.","CleanAbstract":"OBJECTIVES: To investigate the effects of submaximal and vigorous isometric hip adduction on the vastus medialis obliquus (VMO) and vastus lateralis (VL) activity during the leg press exercise from 90° of knee flexion until full extension.DESIGN: Experimental.SETTING: University biomechanics laboratory.PARTICIPANTS: Ten healthy male college students.MAIN OUTCOME MEASURES: Electromyographic (EMG) activation of VMO, VL and hip adductor longus (HAL) of the dominant leg were recorded during double leg press (LP), leg press with submaximal isometric hip adduction force (LP+), and leg press with vigorous isometric hip adduction force (LP++). The VMO, VL muscle activation, as well as the VMO/VL ratio between different leg press exercises were analyzed by MANOVA over concentric and eccentric phases, and in 15° increments of knee flexion motion. The effect size was calculated.RESULTS: Neither LP+ nor LP++ changed the overall VMO-VL activation patterns. Specific to knee angle, however, small to medium effect size was shown with incorporation of isometric hip adduction to the leg press exercise for VMO/VL ratio.CONCLUSION: Targeted training using the leg press exercise to the last 45° of knee extension/flexion with vigorous hip adduction may be useful in promoting a greater VMO/VL ratio.Copyright ? 2012 Elsevier Ltd. All rights reserved."}]25 In addition, Lenhart et al. found that increasing strength of the VMO did change the magnitude of pressure at the patellofemoral joint, but rather made the pressure more medial.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Influence of step rate and quadriceps load distribution on patellofemoral cartilage contact pressures during running.","id":"4536535","page":"2871-2878","type":"article-journal","volume":"48","issue":"11","author":[{"family":"Lenhart","given":"Rachel L"},{"family":"Smith","given":"Colin R"},{"family":"Vignos","given":"Michael F"},{"family":"Kaiser","given":"Jarred"},{"family":"Heiderscheit","given":"Bryan C"},{"family":"Thelen","given":"Darryl G"}],"issued":{"date-parts":[["2015","8","20"]]},"container-title":"Journal of Biomechanics","container-title-short":"J Biomech","journalAbbreviation":"J Biomech","DOI":"10.1016/j.jbiomech.2015.04.036","PMID":"26070646","PMCID":"PMC4536167","citation-label":"4536535","Abstract":"Interventions used to treat patellofemoral pain in runners are often designed to alter patellofemoral mechanics. This study used a computational model to investigate the influence of two interventions, step rate manipulation and quadriceps strengthening, on patellofemoral contact pressures during running. Running mechanics were analyzed using a lower extremity musculoskeletal model that included a knee with six degree-of-freedom tibiofemoral and patellofemoral joints. An elastic foundation model was used to compute articular contact pressures. The lower extremity model was scaled to anthropometric dimensions of 22 healthy adults, who ran on an instrumented treadmill at 90%, 100% and 110% of their preferred step rate. Numerical optimization was then used to predict the muscle forces, secondary tibiofemoral kinematics and all patellofemoral kinematics that would generate the measured primary hip, knee and ankle joint accelerations. Mean and peak patella contact pressures reached 5.0 and 9.7MPa during the midstance phase of running. Increasing step rate by 10% significantly reduced mean contact pressures by 10.4% and contact area by 7.4%, but had small effects on lateral patellar translation and tilt. Enhancing vastus medialis strength did not substantially affect pressure magnitudes or lateral patellar translation, but did shift contact pressure medially toward the patellar median ridge. Thus, the model suggests that step rate tends to primarily modulate the magnitude of contact pressure and contact area, while vastus medialis strengthening has the potential to alter mediolateral pressure locations. These results are relevant to consider in the design of interventions used to prevent or treat patellofemoral pain in runners. Copyright ? 2015 Elsevier Ltd. All rights reserved.","CleanAbstract":"Interventions used to treat patellofemoral pain in runners are often designed to alter patellofemoral mechanics. This study used a computational model to investigate the influence of two interventions, step rate manipulation and quadriceps strengthening, on patellofemoral contact pressures during running. Running mechanics were analyzed using a lower extremity musculoskeletal model that included a knee with six degree-of-freedom tibiofemoral and patellofemoral joints. An elastic foundation model was used to compute articular contact pressures. The lower extremity model was scaled to anthropometric dimensions of 22 healthy adults, who ran on an instrumented treadmill at 90%, 100% and 110% of their preferred step rate. Numerical optimization was then used to predict the muscle forces, secondary tibiofemoral kinematics and all patellofemoral kinematics that would generate the measured primary hip, knee and ankle joint accelerations. Mean and peak patella contact pressures reached 5.0 and 9.7MPa during the midstance phase of running. Increasing step rate by 10% significantly reduced mean contact pressures by 10.4% and contact area by 7.4%, but had small effects on lateral patellar translation and tilt. Enhancing vastus medialis strength did not substantially affect pressure magnitudes or lateral patellar translation, but did shift contact pressure medially toward the patellar median ridge. Thus, the model suggests that step rate tends to primarily modulate the magnitude of contact pressure and contact area, while vastus medialis strengthening has the potential to alter mediolateral pressure locations. These results are relevant to consider in the design of interventions used to prevent or treat patellofemoral pain in runners.Copyright ? 2015 Elsevier Ltd. All rights reserved."}]22 With PFPS typically causing increased lateral force, this may be advantageous to redistribute pressures endured by the joint. Having discussed the methods and potential benefits of VMO targeting, it is interesting to note the results of a study by Syme et al. that compared a generalized quadriceps strengthening program to one that specifically targeted the VMO. They found that while both programs significantly improved pain and function, there was no significant differences in results between the two.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Disability in patients with chronic patellofemoral pain syndrome: a randomised controlled trial of VMO selective training versus general quadriceps strengthening.","id":"4536520","page":"252-263","type":"article-journal","volume":"14","issue":"3","author":[{"family":"Syme","given":"G"},{"family":"Rowe","given":"P"},{"family":"Martin","given":"D"},{"family":"Daly","given":"G"}],"issued":{"date-parts":[["2009","6"]]},"container-title":"Manual Therapy","container-title-short":"Man Ther","journalAbbreviation":"Man Ther","DOI":"10.1016/j.math.2008.02.007","PMID":"18436468","citation-label":"4536520","Abstract":"This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69) were recruited from a hospital orthopaedic clinic and randomised into three groups: (1) physiotherapy with emphasis on selectively retraining the VMO (Selective); (2) physiotherapy with emphasis on general strengthening of the quadriceps femoris muscles (General); and (3) a no-treatment control group (Control). The three groups were then compared before and after an eight-week rehabilitation period. The Selective and General groups demonstrated statistically significant and 'moderate' to 'large' effect size reductions in pain when compared to the Control group. Both the Selective and General groups displayed statistically significant and 'moderate' and 'large' effect size improvements in subjective function and Quality of Life compared to the Control group. Knee flexion excursion during the stance phase of gait, demonstrated that there were no statistical significant differences and only 'trivial' to 'small' effect size differences between the Selective or General groups and the Control group. A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. Both approaches would seem acceptable for rehabilitating patients with PFPS. It may be appropriate to undertake exercises involving selective activation of the vastus medialis early in the rehabilitation process, however, clinicians should not overly focus on selective activation before progressing rehabilitation, especially in more chronic cases with significant participation restrictions.","CleanAbstract":"This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69) were recruited from a hospital orthopaedic clinic and randomised into three groups: (1) physiotherapy with emphasis on selectively retraining the VMO (Selective); (2) physiotherapy with emphasis on general strengthening of the quadriceps femoris muscles (General); and (3) a no-treatment control group (Control). The three groups were then compared before and after an eight-week rehabilitation period. The Selective and General groups demonstrated statistically significant and 'moderate' to 'large' effect size reductions in pain when compared to the Control group. Both the Selective and General groups displayed statistically significant and 'moderate' and 'large' effect size improvements in subjective function and Quality of Life compared to the Control group. Knee flexion excursion during the stance phase of gait, demonstrated that there were no statistical significant differences and only 'trivial' to 'small' effect size differences between the Selective or General groups and the Control group. A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. Both approaches would seem acceptable for rehabilitating patients with PFPS. It may be appropriate to undertake exercises involving selective activation of the vastus medialis early in the rehabilitation process, however, clinicians should not overly focus on selective activation before progressing rehabilitation, especially in more chronic cases with significant participation restrictions."}]26 Therefore, while VMO training may have benefits, it may not be advantageous for therapists to become overly consumed with targeting its activation in every exercise, especially when it can be difficult for some patients to specifically activate.While quadriceps strengthening has the highest level of evidence for its use according to a review by Barton et al., there is increasing evidence for strengthening the hip musculature.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"The 'Best Practice Guide to Conservative Management of Patellofemoral Pain': incorporating level 1 evidence with expert clinical reasoning.","id":"4538415","page":"923-934","type":"article-journal","volume":"49","issue":"14","author":[{"family":"Barton","given":"Christian John"},{"family":"Lack","given":"Simon"},{"family":"Hemmings","given":"Steph"},{"family":"Tufail","given":"Saad"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2015","7"]]},"container-title":"British Journal of Sports Medicine","container-title-short":"Br J Sports Med","journalAbbreviation":"Br J Sports Med","DOI":"10.1136/bjsports-2014-093637","PMID":"25716151","citation-label":"4538415","Abstract":"IMPORTANCE: Patellofemoral pain (PFP) is both chronic and prevalent; it has complex aetiology and many conservative treatment options. OBJECTIVE: Develop a comprehensive contemporary guide to conservative management of PFP outlining key considerations for clinicians to follow. DESIGN: Mixed methods. METHODS: We synthesised the findings from six high-quality systematic reviews to September 2013 with the opinions of 17 experts obtained via semistructured interviews. Experts had at least 5?years clinical experience with PFP as a specialist focus, were actively involved in PFP research and contributed to specialist international meetings. The interviews covered clinical reasoning, perception of current evidence and research priorities. RESULTS: Multimodal intervention including exercise to strengthen the gluteal and quadriceps musculature, manual therapy and taping possessed the strongest evidence. Evidence also supports use of foot orthoses and acupuncture. Interview transcript analysis identified 23 themes and 58 subthemes. Four key over-arching principles to ensure effective management included-(1) PFP is a multifactorial condition requiring an individually tailored multimodal approach. (2) Immediate pain relief should be a priority to gain patient trust. (3) Patient empowerment by emphasising active over passive interventions is important. (4) Good patient education and activity modification is essential. Future research priorities include identifying risk factors, testing effective prevention, developing education strategies, evaluating the influence of psychosocial factors on treatment outcomes and how to address them, evaluating the efficacy of movement pattern retraining and improving clinicians' assessment skills to facilitate optimal individual prescription. CONCLUSIONS AND RELEVANCE: Effective management of PFP requires consideration of a number of proven conservative interventions. An individually tailored multimodal intervention programme including gluteal and quadriceps strengthening, patellar taping and an emphasis on education and activity modification should be prescribed for patients with PFP. We provide a 'Best Practice Guide to Conservative Management of Patellofemoral Pain' outlining key considerations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to .","CleanAbstract":"IMPORTANCE: Patellofemoral pain (PFP) is both chronic and prevalent; it has complex aetiology and many conservative treatment options.OBJECTIVE: Develop a comprehensive contemporary guide to conservative management of PFP outlining key considerations for clinicians to follow.DESIGN: Mixed methods.METHODS: We synthesised the findings from six high-quality systematic reviews to September 2013 with the opinions of 17 experts obtained via semistructured interviews. Experts had at least 5?years clinical experience with PFP as a specialist focus, were actively involved in PFP research and contributed to specialist international meetings. The interviews covered clinical reasoning, perception of current evidence and research priorities.RESULTS: Multimodal intervention including exercise to strengthen the gluteal and quadriceps musculature, manual therapy and taping possessed the strongest evidence. Evidence also supports use of foot orthoses and acupuncture. Interview transcript analysis identified 23 themes and 58 subthemes. Four key over-arching principles to ensure effective management included-(1) PFP is a multifactorial condition requiring an individually tailored multimodal approach. (2) Immediate pain relief should be a priority to gain patient trust. (3) Patient empowerment by emphasising active over passive interventions is important. (4) Good patient education and activity modification is essential. Future research priorities include identifying risk factors, testing effective prevention, developing education strategies, evaluating the influence of psychosocial factors on treatment outcomes and how to address them, evaluating the efficacy of movement pattern retraining and improving clinicians' assessment skills to facilitate optimal individual prescription.CONCLUSIONS AND RELEVANCE: Effective management of PFP requires consideration of a number of proven conservative interventions. An individually tailored multimodal intervention programme including gluteal and quadriceps strengthening, patellar taping and an emphasis on education and activity modification should be prescribed for patients with PFP. We provide a 'Best Practice Guide to Conservative Management of Patellofemoral Pain' outlining key considerations.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to ."}]27 Khayambashi et al. compared a strengthening program of hip abduction and external rotation exercises to one of squats and knee extension exercises and found that, while both resulted in improvements, the hip strengthening program produced greater improvements in pain and health status.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Posterolateral hip muscle strengthening versus quadriceps strengthening for patellofemoral pain: a comparative control trial.","id":"4536562","page":"900-907","type":"article-journal","volume":"95","issue":"5","author":[{"family":"Khayambashi","given":"Khalil"},{"family":"Fallah","given":"Alireza"},{"family":"Movahedi","given":"Ahmadreza"},{"family":"Bagwell","given":"Jennifer"},{"family":"Powers","given":"Christopher"}],"issued":{"date-parts":[["2014","5"]]},"container-title":"Archives of Physical Medicine and Rehabilitation","container-title-short":"Arch Phys Med Rehabil","journalAbbreviation":"Arch Phys Med Rehabil","DOI":"10.1016/j.apmr.2013.12.022","PMID":"24440362","citation-label":"4536562","Abstract":"OBJECTIVE: To compare the efficacy of posterolateral hip muscle strengthening versus quadriceps strengthening in reducing pain and improving health status in persons with patellofemoral pain (PFP). DESIGN: Comparative control trial. SETTING: Rehabilitation facility. PARTICIPANTS: Persons with a diagnosis of PFP (N=36; 18 men, 18 women). INTERVENTIONS: Patients were alternately assigned to a posterolateral hip muscle strengthening group (9 men and 9 women) or a quadriceps strengthening group (9 men and 9 women). The posterolateral hip muscle strengthening group performed hip abductor and external rotator strengthening exercises, whereas the quadriceps strengthening group performed quadriceps strengthening exercises (3 times a week for 8wk). MAIN OUTCOME MEASURES: Pain (visual analog scale [VAS]) and health status (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC]) were assessed at baseline, postintervention, and 6-month follow-up. RESULTS: Significant improvements in VAS and WOMAC scores were observed in both groups from baseline to postintervention and baseline to 6-month follow-up (P< .001). Improvements in VAS and WOMAC scores in the posterolateral hip exercise group were superior to those in the quadriceps exercise group postintervention and at 6-month follow-up (P< .05). CONCLUSIONS: Although both intervention programs resulted in decreased pain and improved function in persons with PFP, outcomes in the posterolateral hip exercise group were superior to the quadriceps exercise group. The superior outcomes obtained in the posterolateral hip exercise group were maintained 6 months postintervention. Copyright ? 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.","CleanAbstract":"OBJECTIVE: To compare the efficacy of posterolateral hip muscle strengthening versus quadriceps strengthening in reducing pain and improving health status in persons with patellofemoral pain (PFP).DESIGN: Comparative control trial.SETTING: Rehabilitation facility.PARTICIPANTS: Persons with a diagnosis of PFP (N=36; 18 men, 18 women).INTERVENTIONS: Patients were alternately assigned to a posterolateral hip muscle strengthening group (9 men and 9 women) or a quadriceps strengthening group (9 men and 9 women). The posterolateral hip muscle strengthening group performed hip abductor and external rotator strengthening exercises, whereas the quadriceps strengthening group performed quadriceps strengthening exercises (3 times a week for 8wk).MAIN OUTCOME MEASURES: Pain (visual analog scale [VAS]) and health status (Western Ontario McMaster Universities Osteoarthritis Index [WOMAC]) were assessed at baseline, postintervention, and 6-month follow-up.RESULTS: Significant improvements in VAS and WOMAC scores were observed in both groups from baseline to postintervention and baseline to 6-month follow-up (PCONCLUSIONS: Although both intervention programs resulted in decreased pain and improved function in persons with PFP, outcomes in the posterolateral hip exercise group were superior to the quadriceps exercise group. The superior outcomes obtained in the posterolateral hip exercise group were maintained 6 months postintervention.Copyright ? 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved."}]28 A review by Rixe et al. describes a study that compared a program of quadriceps strengthening and functional training to one of hip strengthening and functional training, with the hip exercise group experiencing a larger decrease in pain. The same review also discusses a study in which a program of only quadriceps strengthening was compared to one strengthening both the quadriceps and gluteal muscles, and found that the program with the addition of the gluteal exercise was superior for decreasing pain.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"A review of the management of patellofemoral pain syndrome.","id":"4538200","page":"19-28","type":"article-journal","volume":"41","issue":"3","author":[{"family":"Rixe","given":"Jeffrey A"},{"family":"Glick","given":"Joshua E"},{"family":"Brady","given":"Jodi"},{"family":"Olympia","given":"Robert P"}],"issued":{"date-parts":[["2013","9"]]},"container-title":"The Physician and sportsmedicine","container-title-short":"Phys Sportsmed","journalAbbreviation":"Phys Sportsmed","DOI":"10.3810/psm.2013.09.2023","PMID":"24113699","citation-label":"4538200","Abstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS. METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years. RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS. CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.","CleanAbstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS."}]23 Thus, the hip musculature should be considered with the quadriceps when prescribing strengthening for a patient with PFPS. Flexibility exercises also deserve consideration in the intervention plan, yet the evidence for which is lacking in comparison to strengthening exercises. Static quadriceps stretches have been shown to decrease pain, and stretching of the triceps surae and hamstrings has also been recommended.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"A review of the management of patellofemoral pain syndrome.","id":"4538200","page":"19-28","type":"article-journal","volume":"41","issue":"3","author":[{"family":"Rixe","given":"Jeffrey A"},{"family":"Glick","given":"Joshua E"},{"family":"Brady","given":"Jodi"},{"family":"Olympia","given":"Robert P"}],"issued":{"date-parts":[["2013","9"]]},"container-title":"The Physician and sportsmedicine","container-title-short":"Phys Sportsmed","journalAbbreviation":"Phys Sportsmed","DOI":"10.3810/psm.2013.09.2023","PMID":"24113699","citation-label":"4538200","Abstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS. METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years. RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS. CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.","CleanAbstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS."},{"title":"The 'Best Practice Guide to Conservative Management of Patellofemoral Pain': incorporating level 1 evidence with expert clinical reasoning.","id":"4538415","page":"923-934","type":"article-journal","volume":"49","issue":"14","author":[{"family":"Barton","given":"Christian John"},{"family":"Lack","given":"Simon"},{"family":"Hemmings","given":"Steph"},{"family":"Tufail","given":"Saad"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2015","7"]]},"container-title":"British Journal of Sports Medicine","container-title-short":"Br J Sports Med","journalAbbreviation":"Br J Sports Med","DOI":"10.1136/bjsports-2014-093637","PMID":"25716151","citation-label":"4538415","Abstract":"IMPORTANCE: Patellofemoral pain (PFP) is both chronic and prevalent; it has complex aetiology and many conservative treatment options. OBJECTIVE: Develop a comprehensive contemporary guide to conservative management of PFP outlining key considerations for clinicians to follow. DESIGN: Mixed methods. METHODS: We synthesised the findings from six high-quality systematic reviews to September 2013 with the opinions of 17 experts obtained via semistructured interviews. Experts had at least 5?years clinical experience with PFP as a specialist focus, were actively involved in PFP research and contributed to specialist international meetings. The interviews covered clinical reasoning, perception of current evidence and research priorities. RESULTS: Multimodal intervention including exercise to strengthen the gluteal and quadriceps musculature, manual therapy and taping possessed the strongest evidence. Evidence also supports use of foot orthoses and acupuncture. Interview transcript analysis identified 23 themes and 58 subthemes. Four key over-arching principles to ensure effective management included-(1) PFP is a multifactorial condition requiring an individually tailored multimodal approach. (2) Immediate pain relief should be a priority to gain patient trust. (3) Patient empowerment by emphasising active over passive interventions is important. (4) Good patient education and activity modification is essential. Future research priorities include identifying risk factors, testing effective prevention, developing education strategies, evaluating the influence of psychosocial factors on treatment outcomes and how to address them, evaluating the efficacy of movement pattern retraining and improving clinicians' assessment skills to facilitate optimal individual prescription. CONCLUSIONS AND RELEVANCE: Effective management of PFP requires consideration of a number of proven conservative interventions. An individually tailored multimodal intervention programme including gluteal and quadriceps strengthening, patellar taping and an emphasis on education and activity modification should be prescribed for patients with PFP. We provide a 'Best Practice Guide to Conservative Management of Patellofemoral Pain' outlining key considerations. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to .","CleanAbstract":"IMPORTANCE: Patellofemoral pain (PFP) is both chronic and prevalent; it has complex aetiology and many conservative treatment options.OBJECTIVE: Develop a comprehensive contemporary guide to conservative management of PFP outlining key considerations for clinicians to follow.DESIGN: Mixed methods.METHODS: We synthesised the findings from six high-quality systematic reviews to September 2013 with the opinions of 17 experts obtained via semistructured interviews. Experts had at least 5?years clinical experience with PFP as a specialist focus, were actively involved in PFP research and contributed to specialist international meetings. The interviews covered clinical reasoning, perception of current evidence and research priorities.RESULTS: Multimodal intervention including exercise to strengthen the gluteal and quadriceps musculature, manual therapy and taping possessed the strongest evidence. Evidence also supports use of foot orthoses and acupuncture. Interview transcript analysis identified 23 themes and 58 subthemes. Four key over-arching principles to ensure effective management included-(1) PFP is a multifactorial condition requiring an individually tailored multimodal approach. (2) Immediate pain relief should be a priority to gain patient trust. (3) Patient empowerment by emphasising active over passive interventions is important. (4) Good patient education and activity modification is essential. Future research priorities include identifying risk factors, testing effective prevention, developing education strategies, evaluating the influence of psychosocial factors on treatment outcomes and how to address them, evaluating the efficacy of movement pattern retraining and improving clinicians' assessment skills to facilitate optimal individual prescription.CONCLUSIONS AND RELEVANCE: Effective management of PFP requires consideration of a number of proven conservative interventions. An individually tailored multimodal intervention programme including gluteal and quadriceps strengthening, patellar taping and an emphasis on education and activity modification should be prescribed for patients with PFP. We provide a 'Best Practice Guide to Conservative Management of Patellofemoral Pain' outlining key considerations.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to ."}]23,27 Rixe et al. discuss a study in which passive stretching was compared to assisted, adaptive stretching through proprioceptive neuromuscular facilitation (PNF) techniques for the quadriceps and hamstrings, with the PNF group experiencing greater reduction in pain.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"A review of the management of patellofemoral pain syndrome.","id":"4538200","page":"19-28","type":"article-journal","volume":"41","issue":"3","author":[{"family":"Rixe","given":"Jeffrey A"},{"family":"Glick","given":"Joshua E"},{"family":"Brady","given":"Jodi"},{"family":"Olympia","given":"Robert P"}],"issued":{"date-parts":[["2013","9"]]},"container-title":"The Physician and sportsmedicine","container-title-short":"Phys Sportsmed","journalAbbreviation":"Phys Sportsmed","DOI":"10.3810/psm.2013.09.2023","PMID":"24113699","citation-label":"4538200","Abstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS. METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years. RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS. CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.","CleanAbstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS."}]23The use of foot orthotics has limited but growing evidence for use in this population. Lack et al. found that anti-pronating foot orthoses resulted in small reductions in hip adduction and knee internal rotation during running. They also found that in patients with pronated feet, addition of the orthoses resulted in earlier activation of the VMO.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"The immediate effects of foot orthoses on hip and knee kinematics and muscle activity during a functional step-up task in individuals with patellofemoral pain.","id":"4536557","page":"1056-1062","type":"article-journal","volume":"29","issue":"9","author":[{"family":"Lack","given":"Simon"},{"family":"Barton","given":"Christian"},{"family":"Woledge","given":"Roger"},{"family":"Laupheimer","given":"Markus"},{"family":"Morrissey","given":"Dylan"}],"issued":{"date-parts":[["2014","11"]]},"container-title":"Clinical Biomechanics","container-title-short":"Clin Biomech (Bristol, Avon)","journalAbbreviation":"Clin Biomech (Bristol, Avon)","DOI":"10.1016/j.clinbiomech.2014.08.005","PMID":"25441771","citation-label":"4536557","Abstract":"BACKGROUND: Evidence shows that anti-pronating foot orthoses improve patellofemoral pain, but there is a paucity of evidence concerning mechanisms. We investigated the immediate effects of prefabricated foot orthoses on (i) hip and knee kinematics; (ii) electromyography variables of vastus medialis oblique, vastus lateralis and gluteus medius during a functional step-up task, and (iii) associated clinical measures. METHODS: Hip muscle activity and kinematics were measured during a step-up task with and without an anti-pronating foot orthoses, in people (n=20, 9 M, 11 F) with patellofemoral pain. Additionally, we measured knee function, foot posture index, isometric hip abductor and knee extensor strength and weight-bearing ankle dorsiflexion. FINDINGS: Reduced hip adduction (0.82°, P=0.01), knee internal rotation (0.46°, P=0.03), and decreased gluteus medius peak amplitude (0.9mV, P=0.043) were observed after ground contact in the 'with orthoses' condition. With the addition of orthoses, a more pronated foot posture correlated with earlier vastus medialis oblique onset (r=-0.51, P=0.02) whilst higher Kujala scores correlated with earlier gluteus medius onset (r=0.52, P=0.02). INTERPRETATION: Although small in magnitude, reductions in hip adduction, knee internal rotation and gluteus medius amplitude observed immediately following orthoses application during a task that commonly aggravates symptoms, offer a potential mechanism for their effectiveness in patellofemoral pain management. Given the potential for cumulative effects of weight bearing repetitions completed with a foot orthoses, for example during repeated stair ascent, the differences are likely to be clinically meaningful. Copyright ? 2014. Published by Elsevier Ltd.","CleanAbstract":"BACKGROUND: Evidence shows that anti-pronating foot orthoses improve patellofemoral pain, but there is a paucity of evidence concerning mechanisms. We investigated the immediate effects of prefabricated foot orthoses on (i) hip and knee kinematics; (ii) electromyography variables of vastus medialis oblique, vastus lateralis and gluteus medius during a functional step-up task, and (iii) associated clinical measures.METHODS: Hip muscle activity and kinematics were measured during a step-up task with and without an anti-pronating foot orthoses, in people (n=20, 9 M, 11 F) with patellofemoral pain. Additionally, we measured knee function, foot posture index, isometric hip abductor and knee extensor strength and weight-bearing ankle dorsiflexion.FINDINGS: Reduced hip adduction (0.82°, P=0.01), knee internal rotation (0.46°, P=0.03), and decreased gluteus medius peak amplitude (0.9mV, P=0.043) were observed after ground contact in the 'with orthoses' condition. With the addition of orthoses, a more pronated foot posture correlated with earlier vastus medialis oblique onset (r=-0.51, P=0.02) whilst higher Kujala scores correlated with earlier gluteus medius onset (r=0.52, P=0.02).INTERPRETATION: Although small in magnitude, reductions in hip adduction, knee internal rotation and gluteus medius amplitude observed immediately following orthoses application during a task that commonly aggravates symptoms, offer a potential mechanism for their effectiveness in patellofemoral pain management. Given the potential for cumulative effects of weight bearing repetitions completed with a foot orthoses, for example during repeated stair ascent, the differences are likely to be clinically meaningful.Copyright ? 2014. Published by Elsevier Ltd."}]29 A study by Collins et al. found that prefabricated orthoses with some degree of customizability produced greater pain reduction that flat inserts, and were equal in degree of pain improvement compared to physical therapy. No additional benefit was seen when the orthoses were combined with physical therapy.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome: randomised clinical trial.","id":"1544148","page":"a1735","type":"article-journal","volume":"337","author":[{"family":"Collins","given":"Natalie"},{"family":"Crossley","given":"Kay"},{"family":"Beller","given":"Elaine"},{"family":"Darnell","given":"Ross"},{"family":"McPoil","given":"Thomas"},{"family":"Vicenzino","given":"Bill"}],"issued":{"date-parts":[["2008","10","24"]]},"container-title":"BMJ (Clinical Research Ed.)","container-title-short":"BMJ","journalAbbreviation":"BMJ","DOI":"10.1136/bmj.a1735","PMID":"18952682","PMCID":"PMC2572211","citation-label":"1544148","Abstract":"OBJECTIVE: To compare the clinical efficacy of foot orthoses in the management of patellofemoral pain syndrome with flat inserts or physiotherapy, and to investigate the effectiveness of foot orthoses plus physiotherapy. DESIGN: Prospective, single blind, randomised clinical trial. SETTING: Single centre trial within a community setting in Brisbane, Australia. PARTICIPANTS: 179 participants (100 women) aged 18 to 40 years, with a clinical diagnosis of patellofemoral pain syndrome of greater than six weeks' duration, who had no previous treatment with foot orthoses or physiotherapy in the preceding 12 months. INTERVENTIONS: Six weeks of physiotherapist intervention with off the shelf foot orthoses, flat inserts, multimodal physiotherapy (patellofemoral joint mobilisation, patellar taping, quadriceps muscle retraining, and education), or foot orthoses plus physiotherapy. MAIN OUTCOME MEASURES: Global improvement, severity of usual and worst pain over the preceding week, anterior knee pain scale, and functional index questionnaire measured at 6, 12, and 52 weeks. RESULTS: Foot orthoses produced improvement beyond that of flat inserts in the short term, notably at six weeks (relative risk reduction 0.66, 99% confidence interval 0.05 to 1.17; NNT 4 (99% confidence interval 2 to 51). No significant differences were found between foot orthoses and physiotherapy, or between physiotherapy and physiotherapy plus orthoses. All groups showed clinically meaningful improvements in primary outcomes over 52 weeks. CONCLUSION: While foot orthoses are superior to flat inserts according to participants' overall perception, they are similar to physiotherapy and do not improve outcomes when added to physiotherapy in the short term management of patellofemoral pain. Given the long term improvement observed in all treatment groups, general practitioners may seek to hasten recovery by prescribing prefabricated orthoses. TRIAL REGISTRATION: Australian Clinical Trials Registry ACTRN012605000463673 and NCT00118521.","CleanAbstract":"OBJECTIVE: To compare the clinical efficacy of foot orthoses in the management of patellofemoral pain syndrome with flat inserts or physiotherapy, and to investigate the effectiveness of foot orthoses plus physiotherapy.DESIGN: Prospective, single blind, randomised clinical trial.SETTING: Single centre trial within a community setting in Brisbane, Australia.PARTICIPANTS: 179 participants (100 women) aged 18 to 40 years, with a clinical diagnosis of patellofemoral pain syndrome of greater than six weeks' duration, who had no previous treatment with foot orthoses or physiotherapy in the preceding 12 months.INTERVENTIONS: Six weeks of physiotherapist intervention with off the shelf foot orthoses, flat inserts, multimodal physiotherapy (patellofemoral joint mobilisation, patellar taping, quadriceps muscle retraining, and education), or foot orthoses plus physiotherapy.MAIN OUTCOME MEASURES: Global improvement, severity of usual and worst pain over the preceding week, anterior knee pain scale, and functional index questionnaire measured at 6, 12, and 52 weeks.RESULTS: Foot orthoses produced improvement beyond that of flat inserts in the short term, notably at six weeks (relative risk reduction 0.66, 99% confidence interval 0.05 to 1.17; NNT 4 (99% confidence interval 2 to 51). No significant differences were found between foot orthoses and physiotherapy, or between physiotherapy and physiotherapy plus orthoses. All groups showed clinically meaningful improvements in primary outcomes over 52 weeks.CONCLUSION: While foot orthoses are superior to flat inserts according to participants' overall perception, they are similar to physiotherapy and do not improve outcomes when added to physiotherapy in the short term management of patellofemoral pain. Given the long term improvement observed in all treatment groups, general practitioners may seek to hasten recovery by prescribing prefabricated orthoses.TRIAL REGISTRATION: Australian Clinical Trials Registry ACTRN012605000463673 and NCT00118521."}]30Weak evidence exists regarding the use of manual therapy in those with PFPS. A systematic review by Espi-Lopez et al. found that the use of manual therapy techniques such as manipulation and soft tissue therapy alleviated PFPS symptoms when combined with traditional therapy techniques such as strengthening.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Effectiveness of manual therapy combined with physical therapy in treatment of patellofemoral pain syndrome: systematic review.","id":"4046235","page":"139-146","type":"article-journal","volume":"16","issue":"2","author":[{"family":"Espí-López","given":"Gemma Victoria"},{"family":"Arnal-Gómez","given":"Anna"},{"family":"Balasch-Bernat","given":"Mercè"},{"family":"Inglés","given":"Marta"}],"issued":{"date-parts":[["2017","6"]]},"container-title":"Journal of chiropractic medicine","container-title-short":"J Chiropr Med","journalAbbreviation":"J Chiropr Med","DOI":"10.1016/j.jcm.2016.10.003","PMID":"28559754","PMCID":"PMC5440631","citation-label":"4046235","Abstract":"OBJECTIVES: The purpose of this study was to conduct a review of randomized controlled trials (RCTs) to determine the treatment effectiveness of the combination of manual therapy (MT) with other physical therapy techniques. METHODS: Systematic searches of scientific literature were undertaken on PubMed and the Cochrane Library (2004-2014). The following terms were used: \"patellofemoral pain syndrome,\" \"physical therapy,\" \"manual therapy,\" and \"manipulation.\" RCTs that studied adults diagnosed with patellofemoral pain syndrome (PFPS) treated by MT and physical therapy approaches were included. The quality of the studies was assessed by the Jadad Scale. RESULTS: Five RCTs with an acceptable methodological quality (Jadad ≥ 3) were selected. The studies indicated that MT combined with physical therapy has some effect on reducing pain and improving function in PFPS, especially when applied on the full kinetic chain and when strengthening hip and knee muscles. CONCLUSIONS: The different combinations of MT and physical therapy programs analyzed in this review suggest that giving more emphasis to proximal stabilization and full kinetic chain treatments in PFPS will help better alleviation of symptoms.","CleanAbstract":"OBJECTIVES: The purpose of this study was to conduct a review of randomized controlled trials (RCTs) to determine the treatment effectiveness of the combination of manual therapy (MT) with other physical therapy techniques.METHODS: Systematic searches of scientific literature were undertaken on PubMed and the Cochrane Library (2004-2014). The following terms were used: \"patellofemoral pain syndrome,\" \"physical therapy,\" \"manual therapy,\" and \"manipulation.\" RCTs that studied adults diagnosed with patellofemoral pain syndrome (PFPS) treated by MT and physical therapy approaches were included. The quality of the studies was assessed by the Jadad Scale.RESULTS: Five RCTs with an acceptable methodological quality (Jadad ≥ 3) were selected. The studies indicated that MT combined with physical therapy has some effect on reducing pain and improving function in PFPS, especially when applied on the full kinetic chain and when strengthening hip and knee muscles.CONCLUSIONS: The different combinations of MT and physical therapy programs analyzed in this review suggest that giving more emphasis to proximal stabilization and full kinetic chain treatments in PFPS will help better alleviation of symptoms."}]31 However, in this review, studies did not compare the manual therapy intervention to traditional therapy only, so any additional benefits of manual therapy are unclear. A study by van der Dolder et al. found that transverse friction to the lateral retinaculum and medial patellar glides improved knee flexion and stair stepping ability, but not pain, compared to a control group that received no intervention at all.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Six sessions of manual therapy increase knee flexion and improve activity in people with anterior knee pain: a randomised controlled trial.","id":"4538371","page":"261-264","type":"article-journal","volume":"52","issue":"4","author":[{"family":"van den Dolder","given":"Paul A"},{"family":"Roberts","given":"David L"}],"issued":{"date-parts":[["2006"]]},"container-title":"The Australian Journal of Physiotherapy","container-title-short":"Aust J Physiother","journalAbbreviation":"Aust J Physiother","PMID":"17132120","citation-label":"4538371","Abstract":"QUESTION: What are the effects of manual therapy on pain, range of motion, and activity in patients with anterior knee pain? DESIGN: Randomised controlled trial. PARTICIPANTS: Thirty-eight ambulatory care patients (one dropout) with anterior knee pain. INTERVENTION: The experimental intervention consisted of six sessions of manual therapy, while the control intervention was to remain on the waiting list for two weeks. OUTCOME MEASURES: Pain was measured using the Patellofemoral Pain Severity Questionnaire. Active knee flexion and extension was measured from photographs. Activity was measured by having the participants step up and down a 15 cm step, leading with the painful leg as many times as they could in a 60 second period. Measurements were taken before and after intervention by a blinded assessor. RESULTS: The experimental group decreased their pain by -8 mm (95% CI to 1 p =0.08) and pain on stairs by-10, (95% CI -22 to 2 p = 0.10) compared with the control group. They increased their active knee flexion by 10 deg (95% CI TO 16, p = 0.004) and and the number of steps in 60 seconds by 5 (95% CI 2 TO 8, p = 0.001) compared with the control group. CONCLUSION: Manual therapy is effective improving knee flexion and stair climbing i patients with anterior knee pain. There is a trend towards a small improvement in pain.","CleanAbstract":"QUESTION: What are the effects of manual therapy on pain, range of motion, and activity in patients with anterior knee pain?DESIGN: Randomised controlled trial.PARTICIPANTS: Thirty-eight ambulatory care patients (one dropout) with anterior knee pain.INTERVENTION: The experimental intervention consisted of six sessions of manual therapy, while the control intervention was to remain on the waiting list for two weeks.OUTCOME MEASURES: Pain was measured using the Patellofemoral Pain Severity Questionnaire. Active knee flexion and extension was measured from photographs. Activity was measured by having the participants step up and down a 15 cm step, leading with the painful leg as many times as they could in a 60 second period. Measurements were taken before and after intervention by a blinded assessor.RESULTS: The experimental group decreased their pain by -8 mm (95% CI to 1 p =0.08) and pain on stairs by-10, (95% CI -22 to 2 p = 0.10) compared with the control group. They increased their active knee flexion by 10 deg (95% CI TO 16, p = 0.004) and and the number of steps in 60 seconds by 5 (95% CI 2 TO 8, p = 0.001) compared with the control group.CONCLUSION: Manual therapy is effective improving knee flexion and stair climbing i patients with anterior knee pain. There is a trend towards a small improvement in pain."}]32 Patellar mobilization has not shown significant improvement in symptoms, and lumbopelvic manipulation failed to produce functional improvement.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"A systematic review of physical interventions for patellofemoral pain syndrome.","id":"4538381","page":"103-110","type":"article-journal","volume":"11","issue":"2","author":[{"family":"Crossley","given":"K"},{"family":"Bennell","given":"K"},{"family":"Green","given":"S"},{"family":"McConnell","given":"J"}],"issued":{"date-parts":[["2001","4"]]},"container-title":"Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine","container-title-short":"Clin J Sport Med","journalAbbreviation":"Clin J Sport Med","PMID":"11403109","citation-label":"4538381","Abstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS. DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000. STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention. RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others. CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions.","CleanAbstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS.DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000.STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention.RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others.CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions."},{"title":"A review of the management of patellofemoral pain syndrome.","id":"4538200","page":"19-28","type":"article-journal","volume":"41","issue":"3","author":[{"family":"Rixe","given":"Jeffrey A"},{"family":"Glick","given":"Joshua E"},{"family":"Brady","given":"Jodi"},{"family":"Olympia","given":"Robert P"}],"issued":{"date-parts":[["2013","9"]]},"container-title":"The Physician and sportsmedicine","container-title-short":"Phys Sportsmed","journalAbbreviation":"Phys Sportsmed","DOI":"10.3810/psm.2013.09.2023","PMID":"24113699","citation-label":"4538200","Abstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS. METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years. RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS. CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS.","CleanAbstract":"OBJECTIVE: Patellofemoral pain syndrome (PFPS) is one of the most frequently diagnosed knee conditions in the primary care, orthopedic, and sports medicine settings. Although strength training and stretching programs have traditionally been the mainstay of patient treatment, there are no consensus recovery protocols for runners experiencing PFPS. The purpose of our review is to examine recent literature regarding the efficacy of various treatment modalities in the management of patients with PFPS.METHODS: Our review included 33 articles from a PubMed literature search using the search term PFPS treatment. The search was limited to randomized controlled trials, crossover case-controlled studies, and cohort studies with ≥ 10 participants, with trial data that were published within the last 5 years.RESULTS: Strength training and stretching exercises continue to be strongly supported by research as effective treatment options for runners with PFPS. Recent studies have confirmed that quadriceps and hip strengthening combined with stretching in a structured physiotherapy program comprise the most effective treatment for reducing knee pain symptoms and improving functionality in patients with PFPS. As previous studies have shown, therapies such as proprioceptive training, orthotics, and taping may offer benefits as adjunctive therapies but do not show a significant benefit when they are used alone in patients with PFPS. Additionally, recent research has confirmed that surgical and pharmacologic therapies are not effective for the management of patients with PFPS.CONCLUSION: A large number of athletes are impacted by PFPS every year, particularly young runners. Sports medicine researchers have investigated many possible therapies for patients with PFPS; however, no clear guidelines have emerged regarding the management of the syndrome. Our review analyzes recent literature on PFPS and identifies specific treatment recommendations. The most effective and strongly supported treatment modality for patients with PFPS is a combined physiotherapy program, including strength training of the quadriceps and hip abductors and stretching of the quadriceps muscle group. Adjunctive therapies, including taping, biofeedback devices, and prefabricated orthotic inserts, may provide limited additive benefits in select populations. Surgery should be avoided in all patients with PFPS."}]23,33 Those with PFPS have been shown to have increased prevalence of myofascial trigger points, particularly in the gluteus medius and quadratus lumborum, so the effects of myofascial release has been the focus of some studies. Hains and Hains used myofascial therapy with ischemic compression in the peri-patellar and retro-patellar regions in their experimental group and the same techniques in the hip musculature in the control group and found significantly reduced pain in the experimental group.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome managed by ischemic compression to the trigger points located in the peri-patellar and retro-patellar areas: A randomized clinical trial","id":"4538394","page":"201-209","type":"article-journal","volume":"13","issue":"3","author":[{"family":"Hains","given":"Guy"},{"family":"Hains","given":"Fran?ois"}],"issued":{"date-parts":[["2010","9"]]},"container-title":"Clinical Chiropractic","container-title-short":"Clinical Chiropractic","journalAbbreviation":"Clinical Chiropractic","DOI":"10.1016/j.clch.2010.05.001","citation-label":"4538394"}]34 Telles et al compared an experimental group who received both exercise and myofascial release to the rectus femoris and tensor fascia latae muscles to an exercise-only group, and found greater reduction in pain and degree of disability in the combination group, providing the strongest evidence supporting manual therapy.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"The effect of adding myofascial techniques to an exercise programme for patients with anterior knee pain.","id":"2891517","page":"844-850","type":"article-journal","volume":"20","issue":"4","author":[{"family":"Telles","given":"Gustavo"},{"family":"Cristov?o","given":"Delmany R"},{"family":"Belache","given":"Fabiana Azevedo Terra Cunha"},{"family":"Santos","given":"Mariana Rezende Araujo"},{"family":"Almeida","given":"Renato Santos de"},{"family":"Nogueira","given":"Leandro Alberto Calazans"}],"issued":{"date-parts":[["2016","10"]]},"container-title":"Journal of bodywork and movement therapies","container-title-short":"J Bodyw Mov Ther","journalAbbreviation":"J Bodyw Mov Ther","DOI":"10.1016/j.jbmt.2016.02.007","PMID":"27814865","citation-label":"2891517","Abstract":"Anterior knee pain is a common complaint and can cause difficulty with its inability to bear weight. The aim of the study was to analyse the effect of adding myofascial techniques to an exercise programme for patients with anterior knee pain. A clinical trial with 18 patients with a clinical diagnosis of anterior knee pain was conducted. One group (E) with nine individuals was treated with hip muscle strengthening exercises; another group (EM), with nine individuals, had myofascial techniques added. To quantify the results, the Numeric Pain Rating Scale (NPRS) and the Lower Extremity Functional Scale (LEFS) were used. The E group showed an improvement in pain (p?=?0.02), but not in the mean degree of disability. The EM group showed an improvement in pain (p?=?0.01), as well as the degree of disability (p?=?0.008). The effect size analysis showed that participants of the EM group had a greater impact on clinical pain and disability (Cohen's d?=?.35 and .30, respectively). The addition of myofascial techniques should be considered to improve the functionality of the lower limbs and reduce pain in patients with anterior knee pain. Copyright ? 2016 Elsevier Ltd. All rights reserved.","CleanAbstract":"Anterior knee pain is a common complaint and can cause difficulty with its inability to bear weight. The aim of the study was to analyse the effect of adding myofascial techniques to an exercise programme for patients with anterior knee pain. A clinical trial with 18 patients with a clinical diagnosis of anterior knee pain was conducted. One group (E) with nine individuals was treated with hip muscle strengthening exercises; another group (EM), with nine individuals, had myofascial techniques added. To quantify the results, the Numeric Pain Rating Scale (NPRS) and the Lower Extremity Functional Scale (LEFS) were used. The E group showed an improvement in pain (p?=?0.02), but not in the mean degree of disability. The EM group showed an improvement in pain (p?=?0.01), as well as the degree of disability (p?=?0.008). The effect size analysis showed that participants of the EM group had a greater impact on clinical pain and disability (Cohen's d?=?.35 and .30, respectively). The addition of myofascial techniques should be considered to improve the functionality of the lower limbs and reduce pain in patients with anterior knee pain.Copyright ? 2016 Elsevier Ltd. All rights reserved."}]35For other types of conservative interventions, there is an overall lack evidence in support of their use in PFPS management. Electrical stimulation has moderate evidence for utilization in facilitating training of the VMO.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Predictors of treatment response to strengthening and stretching exercises for patellofemoral pain: An examination of patellar alignment.","id":"4536573","page":"494-498","type":"article-journal","volume":"22","issue":"6","author":[{"family":"Peng","given":"Hsien-Te"},{"family":"Song","given":"Chen-Yi"}],"issued":{"date-parts":[["2015","12"]]},"container-title":"The Knee","container-title-short":"Knee","journalAbbreviation":"Knee","DOI":"10.1016/j.knee.2014.10.012","PMID":"26254693","citation-label":"4536573","Abstract":"BACKGROUND: Closed kinetic chain and quadriceps strengthening, combined with flexibility exercises of the lower limb musculature, is a common treatment for patellofemoral pain syndrome (PFPS). The effectiveness has been well documented; however, very little is known about which factors predict treatment success. METHODS: A total of 43 female subjects with PFPS participated in an eight-week progressive leg press (LP) strengthening and stretching exercise program. A decrease of 1.5 cm on a 10 cm visual analog scale (VAS) score was used as an indicator for treatment success. The baseline patellar tilt angle difference (PTA-d) due to quadriceps contraction prior to treatment was evaluated as a predictor of treatment success. The logistic regression and receiver operating characteristics (ROC) curve analysis were performed to investigate the predictive value of PTA-d. RESULTS: PTA-d could significantly predict the treatment success of LP strengthening and stretching exercises. The odds ratio (OR) for having an unsuccessful outcome was 1.19 (95% confidence interval (CI), 1.03-1.39, P< 0.021) per degree increment of PTA-d. The most optimal cut-off value for the clinical discrimination of treatment success after LP strengthening and stretching exercise was -1.5° of PTA-d (sensitivity=0.74, specificity=0.71). The area under the ROC curve was 0.73 (standard error=0.08). CONCLUSIONS: Female patients with PFPS whose quadriceps contraction reduced the lateral patellar tilt prior to LP strengthening and stretching exercise treatment are more likely to experience pain relief. It seems clinically important to check dynamic patellar tilt characteristics before treatment to aid in clinical decision making. Copyright ? 2014 Elsevier B.V. All rights reserved.","CleanAbstract":"BACKGROUND: Closed kinetic chain and quadriceps strengthening, combined with flexibility exercises of the lower limb musculature, is a common treatment for patellofemoral pain syndrome (PFPS). The effectiveness has been well documented; however, very little is known about which factors predict treatment success.METHODS: A total of 43 female subjects with PFPS participated in an eight-week progressive leg press (LP) strengthening and stretching exercise program. A decrease of 1.5 cm on a 10 cm visual analog scale (VAS) score was used as an indicator for treatment success. The baseline patellar tilt angle difference (PTA-d) due to quadriceps contraction prior to treatment was evaluated as a predictor of treatment success. The logistic regression and receiver operating characteristics (ROC) curve analysis were performed to investigate the predictive value of PTA-d.RESULTS: PTA-d could significantly predict the treatment success of LP strengthening and stretching exercises. The odds ratio (OR) for having an unsuccessful outcome was 1.19 (95% confidence interval (CI), 1.03-1.39, PCONCLUSIONS: Female patients with PFPS whose quadriceps contraction reduced the lateral patellar tilt prior to LP strengthening and stretching exercise treatment are more likely to experience pain relief. It seems clinically important to check dynamic patellar tilt characteristics before treatment to aid in clinical decision making.Copyright ? 2014 Elsevier B.V. All rights reserved."}]36 A study also found that electrical stimulation to the VMO, gluteus medius, hip adductors, and hamstrings decreased pain by 65.3% during performance of single-leg squats in those with PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Immediate effect of patterned electrical neuromuscular stimulation on pain and muscle activation in individuals with patellofemoral pain.","id":"4538401","page":"118-128","type":"article-journal","volume":"51","issue":"2","author":[{"family":"Glaviano","given":"Neal R"},{"family":"Saliba","given":"Susan A"}],"issued":{"date-parts":[["2016","2"]]},"container-title":"Journal of Athletic Training","container-title-short":"J Athl Train","journalAbbreviation":"J Athl Train","DOI":"10.4085/1062-6050-51.4.06","PMID":"26967547","PMCID":"PMC4852317","citation-label":"4538401","Abstract":"CONTEXT: For individuals with patellofemoral pain (PFP), altered muscle activity and pain are common during functional tasks. Clinicians often seek interventions to improve muscle activity and reduce impairments. One intervention that has not been examined in great detail is electrical stimulation. OBJECTIVE: To determine whether a single patterned electrical neuromuscular stimulation (PENS) treatment would alter muscle activity and pain in individuals with PFP during 2 functional tasks, a single-legged squat and a lateral step down. DESIGN: Cohort study. SETTING: Sports medicine research laboratory. PATIENTS OF OTHER PARTICIPANTS: A total of 22 individuals with PFP (15 women, 7 men; age = 26.0 ± 7.9 years, height = 173.8 ± 8.1 cm, mass = 75.1 ± 17.9 kg). INTERVENTION(S): Participants were randomized into 2 intervention groups: a 15-minute PENS treatment that produced a strong motor response or a 15-minute 1-mA subsensory (sham) treatment. MAIN OUTCOME MEASURE(S): Before and immediately after the intervention, we assessed normalized electromyography amplitude, percentage of activation time across functional tasks, and onset of activation for the vastus medialis oblique, vastus lateralis, gluteus medius, adductor longus, biceps femoris, and medial gastrocnemius muscles during a single-legged squat and a lateral step down. Scores on the visual analog scale for pain were recorded before and after the intervention. RESULTS: After a single treatment of PENS, the percentage of gluteus medius activation increased (0.024) during the lateral step down. Visual analog scores decreased during both the single-legged squat (PENS: preintervention = 2.7 ± 1.9, postintervention = 0.9 ± 0.7; sham: preintervention = 3.2 ± 1.6, postintervention = 2.8 ± 1.9; group × time interaction: P = .041) and lateral step down (PENS: preintervention = 3.4 ± 2.4, postintervention = 1.1 ± 0.8; sham: preintervention = 3.9 ± 1.7, postintervention = 3.3 ± 2.0; group × time interaction: P = .023). No changes in electromyography or pain measures were noted in the sham group. CONCLUSIONS: The PFP participants who received PENS had immediate improvement in gluteus medius activation and a reduction in pain during functional tasks.","CleanAbstract":"CONTEXT: For individuals with patellofemoral pain (PFP), altered muscle activity and pain are common during functional tasks. Clinicians often seek interventions to improve muscle activity and reduce impairments. One intervention that has not been examined in great detail is electrical stimulation.OBJECTIVE: To determine whether a single patterned electrical neuromuscular stimulation (PENS) treatment would alter muscle activity and pain in individuals with PFP during 2 functional tasks, a single-legged squat and a lateral step down.DESIGN: Cohort study.SETTING: Sports medicine research laboratory. PATIENTS OF OTHER PARTICIPANTS: A total of 22 individuals with PFP (15 women, 7 men; age = 26.0 ± 7.9 years, height = 173.8 ± 8.1 cm, mass = 75.1 ± 17.9 kg).INTERVENTION(S): Participants were randomized into 2 intervention groups: a 15-minute PENS treatment that produced a strong motor response or a 15-minute 1-mA subsensory (sham) treatment.MAIN OUTCOME MEASURE(S): Before and immediately after the intervention, we assessed normalized electromyography amplitude, percentage of activation time across functional tasks, and onset of activation for the vastus medialis oblique, vastus lateralis, gluteus medius, adductor longus, biceps femoris, and medial gastrocnemius muscles during a single-legged squat and a lateral step down. Scores on the visual analog scale for pain were recorded before and after the intervention.RESULTS: After a single treatment of PENS, the percentage of gluteus medius activation increased (0.024) during the lateral step down. Visual analog scores decreased during both the single-legged squat (PENS: preintervention = 2.7 ± 1.9, postintervention = 0.9 ± 0.7; sham: preintervention = 3.2 ± 1.6, postintervention = 2.8 ± 1.9; group × time interaction: P = .041) and lateral step down (PENS: preintervention = 3.4 ± 2.4, postintervention = 1.1 ± 0.8; sham: preintervention = 3.9 ± 1.7, postintervention = 3.3 ± 2.0; group × time interaction: P = .023). No changes in electromyography or pain measures were noted in the sham group.CONCLUSIONS: The PFP participants who received PENS had immediate improvement in gluteus medius activation and a reduction in pain during functional tasks."}]37 Ultrasound and low-level laser have not been shown to have an effect on pain in PFPS.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Evidence Based Conservative Management of Patello-femoral Syndrome.","id":"4538190","page":"4-6","type":"article-journal","volume":"2","issue":"1","author":[{"family":"Rodriguez-Merchan","given":"E Carlos"}],"issued":{"date-parts":[["2014","3","15"]]},"container-title":"Archives of bone and joint surgery","container-title-short":"Arch Bone Jt Surg","journalAbbreviation":"Arch Bone Jt Surg","PMID":"25207305","PMCID":"PMC4151435","citation-label":"4538190","Abstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed."},{"title":"A systematic review of physical interventions for patellofemoral pain syndrome.","id":"4538381","page":"103-110","type":"article-journal","volume":"11","issue":"2","author":[{"family":"Crossley","given":"K"},{"family":"Bennell","given":"K"},{"family":"Green","given":"S"},{"family":"McConnell","given":"J"}],"issued":{"date-parts":[["2001","4"]]},"container-title":"Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine","container-title-short":"Clin J Sport Med","journalAbbreviation":"Clin J Sport Med","PMID":"11403109","citation-label":"4538381","Abstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS. DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000. STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention. RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others. CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions.","CleanAbstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS.DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000.STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention.RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others.CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions."}]33,38 Taping techniques have also not shown significant effects on pain or muscle activation patterns.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Evidence Based Conservative Management of Patello-femoral Syndrome.","id":"4538190","page":"4-6","type":"article-journal","volume":"2","issue":"1","author":[{"family":"Rodriguez-Merchan","given":"E Carlos"}],"issued":{"date-parts":[["2014","3","15"]]},"container-title":"Archives of bone and joint surgery","container-title-short":"Arch Bone Jt Surg","journalAbbreviation":"Arch Bone Jt Surg","PMID":"25207305","PMCID":"PMC4151435","citation-label":"4538190","Abstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed."},{"title":"A systematic review of physical interventions for patellofemoral pain syndrome.","id":"4538381","page":"103-110","type":"article-journal","volume":"11","issue":"2","author":[{"family":"Crossley","given":"K"},{"family":"Bennell","given":"K"},{"family":"Green","given":"S"},{"family":"McConnell","given":"J"}],"issued":{"date-parts":[["2001","4"]]},"container-title":"Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine","container-title-short":"Clin J Sport Med","journalAbbreviation":"Clin J Sport Med","PMID":"11403109","citation-label":"4538381","Abstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS. DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000. STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention. RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others. CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions.","CleanAbstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS.DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000.STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention.RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others.CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions."},{"title":"Mcconnell's patellar taping does not alter knee and hip muscle activation differences during proprioceptive exercises: A randomized placebo-controlled trial in women with patellofemoral pain syndrome.","id":"4538373","page":"72-80","type":"article-journal","volume":"31","author":[{"family":"Araújo","given":"Cynthia Gobbi Alves"},{"family":"de Souza Guerino Macedo","given":"Christiane"},{"family":"Ferreira","given":"Daiene"},{"family":"Shigaki","given":"Leonardo"},{"family":"da Silva","given":"Rubens A"}],"issued":{"date-parts":[["2016","12"]]},"container-title":"Journal of Electromyography and Kinesiology","container-title-short":"J Electromyogr Kinesiol","journalAbbreviation":"J Electromyogr Kinesiol","DOI":"10.1016/j.jelekin.2016.09.006","PMID":"27693990","citation-label":"4538373","Abstract":"The purpose of this study was to assess the effect of patellar taping on muscle activation of the knee and hip muscles in women with Patellofemoral Pain Syndrome during five proprioceptive exercises. Forty sedentary women with syndrome were randomly allocated in two groups: Patellar Taping (based in McConnell) and Placebo (vertical taping on patella without any stretching of lateral structures of the knee). Volunteers performed five proprioceptive exercises randomly: Swing apparatus, Mini-trampoline, Bosu balance ball, Anteroposterior sway on a rectangular board and Mediolateral sway on a rectangular board. All exercises were performed in one-leg stance position with injured knee at flexion of 30° during 15s. Muscle activation was measured by surface electromyography across Vastus Medialis, Vastus Lateralis and Gluteus medius muscles. Maximal voluntary contraction was performed for both hip and knee muscles in order to normalize electromyography signal relative to maximum effort during the exercises. ANOVA results reported no significant interaction (P>0.05) and no significant differences (P>0.05) between groups and intervention effects in all exercise conditions. Significant differences (P< 0.01) were only reported between muscles, where hip presented higher activity than knee muscles. Patellar taping is not better than placebo for changes in the muscular activity of both hip and knee muscles during proprioceptive exercises. TRIAL REGISTRATION NUMBER: NCT02322515. Copyright ?? 2016 Elsevier Ltd. All rights reserved.","CleanAbstract":"The purpose of this study was to assess the effect of patellar taping on muscle activation of the knee and hip muscles in women with Patellofemoral Pain Syndrome during five proprioceptive exercises. Forty sedentary women with syndrome were randomly allocated in two groups: Patellar Taping (based in McConnell) and Placebo (vertical taping on patella without any stretching of lateral structures of the knee). Volunteers performed five proprioceptive exercises randomly: Swing apparatus, Mini-trampoline, Bosu balance ball, Anteroposterior sway on a rectangular board and Mediolateral sway on a rectangular board. All exercises were performed in one-leg stance position with injured knee at flexion of 30° during 15s. Muscle activation was measured by surface electromyography across Vastus Medialis, Vastus Lateralis and Gluteus medius muscles. Maximal voluntary contraction was performed for both hip and knee muscles in order to normalize electromyography signal relative to maximum effort during the exercises. ANOVA results reported no significant interaction (P>0.05) and no significant differences (P>0.05) between groups and intervention effects in all exercise conditions. Significant differences (PTRIAL REGISTRATION NUMBER: NCT02322515.Copyright ?? 2016 Elsevier Ltd. All rights reserved."}]33,38,39 Bracing may have preventative effects for pain, but overall has not been demonstrated to have significant beneifts.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Evidence Based Conservative Management of Patello-femoral Syndrome.","id":"4538190","page":"4-6","type":"article-journal","volume":"2","issue":"1","author":[{"family":"Rodriguez-Merchan","given":"E Carlos"}],"issued":{"date-parts":[["2014","3","15"]]},"container-title":"Archives of bone and joint surgery","container-title-short":"Arch Bone Jt Surg","journalAbbreviation":"Arch Bone Jt Surg","PMID":"25207305","PMCID":"PMC4151435","citation-label":"4538190","Abstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is defined as pain surrounding the patella when sitting with bent knees for prolonged periods of time or when performing activities like ascending or descending stairs, squatting or athletic activities. Patella dislocation is not included in PFPS. This review analyzes the evidence based conservative management of PFPS. A Cochrane Library search related to PFPS was performed until 18 January 2014. The key words were: patellofemoral pain syndrome. Eight papers were found, of which three were reviewed because they were focused on the topic of the article. We also searched the PubMed using the following keywords: evidence based conservative management of patellofemoral pain syndrome. Twelve articles were found, of which seven were reviewed because they were focused on the topic of the article. Overall ten articles were analyzed. Different treatments can be tried for PFPS, including pharmacotherapy, therapeutic ultrasound, exercise therapy, and taping and braces. Non-steroidal anti-inflammatory drugs (NSAIDs) may reduce pain in the short term, but pain does not improve after three months. Therapeutic ultrasound appears not to have a clinically important effect on pain relief for patients with PFPS. The evidence that exercise therapy is more effective in treating PFPS than no exercise is limited with respect to pain reduction, and conflicting with respect to functional improvement. No significant difference has been found between taping and non-taping. The role of knee braces is still controversial. More well-designed studies are needed."},{"title":"A systematic review of physical interventions for patellofemoral pain syndrome.","id":"4538381","page":"103-110","type":"article-journal","volume":"11","issue":"2","author":[{"family":"Crossley","given":"K"},{"family":"Bennell","given":"K"},{"family":"Green","given":"S"},{"family":"McConnell","given":"J"}],"issued":{"date-parts":[["2001","4"]]},"container-title":"Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine","container-title-short":"Clin J Sport Med","journalAbbreviation":"Clin J Sport Med","PMID":"11403109","citation-label":"4538381","Abstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS. DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000. STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention. RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others. CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions.","CleanAbstract":"OBJECTIVE: Physical interventions (nonpharmacological and nonsurgical) are the mainstay of treatment for patellofemoral pain syndrome (PFPS). Physiotherapy is the most common of all physical interventions and includes specific vastus medialis obliquus or general quadriceps strengthening and/or realignment procedures (tape, brace, stretching). These treatments appear to be based on sound theoretical rationale and have attained widespread acceptance, but evidence for the efficacy of these interventions is not well established. This review will present the available evidence for physical interventions for PFPS.DATA SOURCES: Computerized bibliographic databases (MEDLINE, Current Contents, CINAHL) were searched, including the keywords \"patellofemoral,\" \"patella,\" and \"anterior knee pain,\" combined with \"treatment,\" \"rehabilitation,\" and limited to clinical trials through October 2000.STUDY SELECTION: The critical eligibility criteria used for inclusion were that the study be a controlled trial, that outcome assessments were adequately described, and that the treatment was a nonpharmacological, nonsurgical physical intervention.RESULTS: Of the 89 potentially relevant titles, 16 studies were reviewed and none of these fulfilled all of the requirements for a randomized, controlled trial. Physiotherapy interventions were evaluated in eight trials, and the remaining eight trials examined different physical interventions. Significant reductions in PFPS symptoms were found with a corrective foot orthosis and a progressive resistance brace, but there is no evidence to support the use of patellofemoral orthoses, acupuncture, low-level laser, chiropractic patellar mobilization, or patellar taping. Overall the physiotherapy interventions had significant beneficial effects but these interventions were not compared with a placebo control. There is inconclusive evidence to support the superiority of one physiotherapy intervention compared with others.CONCLUSIONS: The evidence to support the use of physical interventions in the management of PFPS is limited. There appears to be a consistent improvement in short-term pain and function due to physiotherapy treatment, but comparison with a placebo group is required to determine efficacy, and further trials are warranted for the other interventions."}]33,38 Pharmacological interventions may also lack utility, as there is limited evidence for the efficacy of non-steroidal anti-inflammatory drugs, and intramuscular injections of glycosaminoglycan polysulphate, a protein molecule that binds water to tissues, has had conflicting results.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Pharmacotherapy for patellofemoral pain syndrome.","id":"4251767","page":"CD003470","type":"article-journal","issue":"3","author":[{"family":"Heintjes","given":"E"},{"family":"Berger","given":"M Y"},{"family":"Bierma-Zeinstra","given":"S M A"},{"family":"Bernsen","given":"R M D"},{"family":"Verhaar","given":"J A N"},{"family":"Koes","given":"B W"}],"issued":{"date-parts":[["2004"]]},"container-title":"Cochrane Database of Systematic Reviews","container-title-short":"Cochrane Database Syst Rev","journalAbbreviation":"Cochrane Database Syst Rev","DOI":"10.1002/14651858.CD003470.pub2","PMID":"15266488","citation-label":"4251767"}]40Surgical intervention is generally not indicated in PFPS unless multiple conservative methods have failed. Lateral retinacular release was thought to be a beneficial approach to reduce the lateral tension acting on the patella, and some studies have reported short-term pain benefits, but overall less than 25% of PFPS benefit from this procedure long-term.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Lateral patellar retinacular release: changes over the last ten years.","id":"4540751","page":"442-449","type":"article-journal","volume":"52","issue":"4","author":[{"family":"Fonseca","given":"Leonardo Pini Rosalem Marciano da"},{"family":"Kawatake","given":"Ednei Haruo"},{"family":"Pochini","given":"Alberto de Castro"}],"issued":{"date-parts":[["2017","7"]]},"container-title":"Revista brasileira de ortopedia","container-title-short":"Rev Bras Ortop","journalAbbreviation":"Rev Bras Ortop","DOI":"10.1016/j.rboe.2017.06.003","PMID":"28884103","PMCID":"PMC5582814","citation-label":"4540751","Abstract":"Lateral retinacular release is a useful resource in knee surgery that can be used for disorders of the extensor mechanism. For many years, it was indiscriminately used in the treatment of the various patellofemoral joint alterations, with conflicting functional results. This study aimed to analyze the changes that have occurred in the indications and clinical effectiveness of lateral retinacular release by reviewing the relevant literature of the past ten years, comparing it to the classic literature on the subject. It was found that less extensive releases decompress the lateral patellar facet, helping with pain control, while decreasing the risks of medial subluxation. Nowadays, there is clear evidence for its indication in the lateral patellar hypercompression syndrome associated with anterior knee pain, as long as there is no related instability; furthermore, it will normally play an adjuvant role in extensor mechanism alignment surgeries for cases of recurrent patellar instability. The initial results for symptomatic patellofemoral osteoarthritis are promising when lateral release is combined with cartilage debridement; in total knee replacement, it is more commonly used for the correction of valgus deformity in order to improve the components' congruency. Finally, distinguishing the different patellofemoral joint pathologies is seen as crucial in order to indicate this procedure. Further randomized control trials that compare surgical techniques with long-term results are still needed.","CleanAbstract":"Lateral retinacular release is a useful resource in knee surgery that can be used for disorders of the extensor mechanism. For many years, it was indiscriminately used in the treatment of the various patellofemoral joint alterations, with conflicting functional results. This study aimed to analyze the changes that have occurred in the indications and clinical effectiveness of lateral retinacular release by reviewing the relevant literature of the past ten years, comparing it to the classic literature on the subject. It was found that less extensive releases decompress the lateral patellar facet, helping with pain control, while decreasing the risks of medial subluxation. Nowadays, there is clear evidence for its indication in the lateral patellar hypercompression syndrome associated with anterior knee pain, as long as there is no related instability; furthermore, it will normally play an adjuvant role in extensor mechanism alignment surgeries for cases of recurrent patellar instability. The initial results for symptomatic patellofemoral osteoarthritis are promising when lateral release is combined with cartilage debridement; in total knee replacement, it is more commonly used for the correction of valgus deformity in order to improve the components' congruency. Finally, distinguishing the different patellofemoral joint pathologies is seen as crucial in order to indicate this procedure. Further randomized control trials that compare surgical techniques with long-term results are still needed."},{"title":"Patellofemoral pain: an update on diagnostic and treatment options.","id":"4540903","page":"188-194","type":"article-journal","volume":"6","issue":"2","author":[{"family":"McCarthy","given":"Moira M"},{"family":"Strickland","given":"Sabrina M"}],"issued":{"date-parts":[["2013","6"]]},"container-title":"Current reviews in musculoskeletal medicine","container-title-short":"Curr Rev Musculoskelet Med","journalAbbreviation":"Curr Rev Musculoskelet Med","DOI":"10.1007/s12178-013-9159-x","PMID":"23456237","PMCID":"PMC3702777","citation-label":"4540903","Abstract":"Patellofemoral pain is a frequent and often challenging clinical problem. It affects females more than males and includes many different pathologic entities that result in pain in the anterior aspect of the knee. Diagnosis of the specific cause of pain can be difficult and requires assessment of lower extremity strength, alignment, and range of motion, as well as specific patella alignment, tracking, and mobility. The treatment for patellofemoral pain is usually conservative with anti-inflammatory medications, activity modification, and a specific physical therapy program focusing on strengthening and flexibility. Infrequently, surgical treatment may be indicated after a non-operative program fails. The outcomes of surgical management may include debridement, lateral release, and realignment of the extensor mechanism to unload the patellofemoral articulation are favorable.","CleanAbstract":"Patellofemoral pain is a frequent and often challenging clinical problem. It affects females more than males and includes many different pathologic entities that result in pain in the anterior aspect of the knee. Diagnosis of the specific cause of pain can be difficult and requires assessment of lower extremity strength, alignment, and range of motion, as well as specific patella alignment, tracking, and mobility. The treatment for patellofemoral pain is usually conservative with anti-inflammatory medications, activity modification, and a specific physical therapy program focusing on strengthening and flexibility. Infrequently, surgical treatment may be indicated after a non-operative program fails. The outcomes of surgical management may include debridement, lateral release, and realignment of the extensor mechanism to unload the patellofemoral articulation are favorable."}]41,42 A cadaveric study by Ostermeier et al. found that lateral retinacular release did not correct patellar tracking or alter contact pressures in the joint.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Dynamic measurement of patellofemoral kinematics and contact pressure after lateral retinacular release: an in vitro study.","id":"4540906","page":"547-554","type":"article-journal","volume":"15","issue":"5","author":[{"family":"Ostermeier","given":"Sven"},{"family":"Holst","given":"Marc"},{"family":"Hurschler","given":"Christof"},{"family":"Windhagen","given":"Henning"},{"family":"Stukenborg-Colsman","given":"Christina"}],"issued":{"date-parts":[["2007","5"]]},"container-title":"Knee Surgery, Sports Traumatology, Arthroscopy","container-title-short":"Knee Surg Sports Traumatol Arthrosc","journalAbbreviation":"Knee Surg Sports Traumatol Arthrosc","DOI":"10.1007/s00167-006-0261-0","PMID":"17225178","citation-label":"4540906","Abstract":"The purpose of this study was to investigate the influence of lateral retinacular release and medial and lateral retinacular deficiency on patellofemoral position and retropatellar contact pressure. Human knee specimens (n = 8, mean age = 65 SD 7 years, all male) were tested in a kinematic knee-simulating machine. During simulation of an isokinetic knee extension cycle from 120 degrees to full extension, a hydraulic cylinder applied sufficient force to the quadriceps tendon to produce an extension moment of 31 Nm. The position of the patella was measured using an ultrasound based motion analysis system (CMS 100, Zebris). The amount of patellofemoral contact pressure and its pressure distribution was measured using a pressure sensitive film (Tekscan, Boston). Patellar position and contact pressure were first investigated in intact knee conditions, after a lateral retinacular release and a release of the medial and lateral retinaculum. After lateral retinacular release the patella continuously moved from a significant medialised position at flexion (P = 0.01) to a lateralised position (P = 0.02) at full knee extension compared to intact conditions, the centre of patellofemoral contact pressure was significantly medialised (0.04) between 120 degrees and 60 degrees knee flexion. Patellofemoral contact pressure did not change significantly. In the deficient knee conditions the patella moved on a significant lateralised track (P = 0.04) through the entire extension cycle with a lateralised centre of patellofemoral pressure (P = 0.04) with a trend (P = 0.08) towards increased patellofemoral pressure. The results suggest that lateral retinacular release did not inevitably stabilise or medialise patellar tracking through the entire knee extension cycle, but could decrease pressure on the lateral patellar facet in knee flexion. Therefore lateral retinacular release should be considered carefully in cases of patellar instability.","CleanAbstract":"The purpose of this study was to investigate the influence of lateral retinacular release and medial and lateral retinacular deficiency on patellofemoral position and retropatellar contact pressure. Human knee specimens (n = 8, mean age = 65 SD 7 years, all male) were tested in a kinematic knee-simulating machine. During simulation of an isokinetic knee extension cycle from 120 degrees to full extension, a hydraulic cylinder applied sufficient force to the quadriceps tendon to produce an extension moment of 31 Nm. The position of the patella was measured using an ultrasound based motion analysis system (CMS 100, Zebris). The amount of patellofemoral contact pressure and its pressure distribution was measured using a pressure sensitive film (Tekscan, Boston). Patellar position and contact pressure were first investigated in intact knee conditions, after a lateral retinacular release and a release of the medial and lateral retinaculum. After lateral retinacular release the patella continuously moved from a significant medialised position at flexion (P = 0.01) to a lateralised position (P = 0.02) at full knee extension compared to intact conditions, the centre of patellofemoral contact pressure was significantly medialised (0.04) between 120 degrees and 60 degrees knee flexion. Patellofemoral contact pressure did not change significantly. In the deficient knee conditions the patella moved on a significant lateralised track (P = 0.04) through the entire extension cycle with a lateralised centre of patellofemoral pressure (P = 0.04) with a trend (P = 0.08) towards increased patellofemoral pressure. The results suggest that lateral retinacular release did not inevitably stabilise or medialise patellar tracking through the entire knee extension cycle, but could decrease pressure on the lateral patellar facet in knee flexion. Therefore lateral retinacular release should be considered carefully in cases of patellar instability."}]43 An alternative surgery is a transfer of the tibial tuberosity to a more medial position to alter the angle of pull of lateral structures, which was shown by Fulkerson et al. to decrease patellofemoral contact stress, but other studies experienced limited success with the technique.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Anteromedial tibial tubercle transfer without bone graft.","id":"4540893","page":"490-6; discussion 496","type":"article-journal","volume":"18","issue":"5","author":[{"family":"Fulkerson","given":"J P"},{"family":"Becker","given":"G J"},{"family":"Meaney","given":"J A"},{"family":"Miranda","given":"M"},{"family":"Folcik","given":"M A"}],"issued":{"date-parts":[["1990","10"]]},"container-title":"The American Journal of Sports Medicine","container-title-short":"Am J Sports Med","journalAbbreviation":"Am J Sports Med","DOI":"10.1177/036354659001800508","PMID":"2252090","citation-label":"4540893","Abstract":"We followed 30 patients for more than 2 years after anteromedial tibial tubercle transfer for persistent patellofemoral pain associated with patellar articular degeneration. Twelve of these patients were followed more than 5 years. We report 93% good and excellent results subjectively and 89% good and excellent results objectively. The quality of improvement was sustained in all 12 of the patients who were evaluated again after more than 5 years from surgery. When examined separately, 75% of those patients with advanced patellar arthrosis achieved a good result; none of these patients achieved an excellent result. Postoperative continuous passive motion has markedly reduced the incidence of stiffness. Serious complications such as compartment syndrome, infection, and skin slough were avoided completely in 51 consecutive cases. Patellofemoral contact pressure studies in five cadaver knees have shown that anteromedial tibial tubercle transfer can provide substantial reduction of patellofemoral contact stress while helping to balance medial and lateral facet pressures. This surgical procedure is mechanically and clinically successful for alleviating intractable pain related to patellar malalignment and articular degeneration. This procedure enables the majority of appropriately selected patients with malalignment and patellar articular degeneration to resume increased levels of activity with substantially diminished pain.","CleanAbstract":"We followed 30 patients for more than 2 years after anteromedial tibial tubercle transfer for persistent patellofemoral pain associated with patellar articular degeneration. Twelve of these patients were followed more than 5 years. We report 93% good and excellent results subjectively and 89% good and excellent results objectively. The quality of improvement was sustained in all 12 of the patients who were evaluated again after more than 5 years from surgery. When examined separately, 75% of those patients with advanced patellar arthrosis achieved a good result; none of these patients achieved an excellent result. Postoperative continuous passive motion has markedly reduced the incidence of stiffness. Serious complications such as compartment syndrome, infection, and skin slough were avoided completely in 51 consecutive cases. Patellofemoral contact pressure studies in five cadaver knees have shown that anteromedial tibial tubercle transfer can provide substantial reduction of patellofemoral contact stress while helping to balance medial and lateral facet pressures. This surgical procedure is mechanically and clinically successful for alleviating intractable pain related to patellar malalignment and articular degeneration. This procedure enables the majority of appropriately selected patients with malalignment and patellar articular degeneration to resume increased levels of activity with substantially diminished pain."},{"title":"Evaluation of the modified Elmslie-Trillat procedure for patellofemoral dysfunction.","id":"4540645","page":"13","type":"article-journal","volume":"33","issue":"1","author":[{"family":"Dannawi","given":"Zaher"},{"family":"Khanduja","given":"Vikas"},{"family":"Palmer","given":"Chris R"},{"family":"El-Zebdeh","given":"Mustafa"}],"issued":{"date-parts":[["2010","1"]]},"container-title":"Orthopedics","container-title-short":"Orthopedics","journalAbbreviation":"Orthopedics","DOI":"10.3928/01477447-20091124-07","PMID":"20055341","citation-label":"4540645","Abstract":"The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability. Copyright 2010, SLACK Incorporated.","CleanAbstract":"The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability.Copyright 2010, SLACK Incorporated."}]44,45 The Elmslie-Trillat procedure combines lateral retinacular release with a tibial tuberosity transfer, and while it has been shown to have excellent results in those with patellar instability, only 34% of PFPS patients had satisfactory results.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Evaluation of the modified Elmslie-Trillat procedure for patellofemoral dysfunction.","id":"4540645","page":"13","type":"article-journal","volume":"33","issue":"1","author":[{"family":"Dannawi","given":"Zaher"},{"family":"Khanduja","given":"Vikas"},{"family":"Palmer","given":"Chris R"},{"family":"El-Zebdeh","given":"Mustafa"}],"issued":{"date-parts":[["2010","1"]]},"container-title":"Orthopedics","container-title-short":"Orthopedics","journalAbbreviation":"Orthopedics","DOI":"10.3928/01477447-20091124-07","PMID":"20055341","citation-label":"4540645","Abstract":"The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability. Copyright 2010, SLACK Incorporated.","CleanAbstract":"The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability.Copyright 2010, SLACK Incorporated."}]45ConclusionOverall, the ambiguity of the exact etiology of PFPS can make diagnosis and management seem muddled with uncertainty. In addition to utilization of the discussed assessment techniques, diagnosis can be strengthened with careful gathering of the patient’s history and symptoms and with consideration of other knee pathologies that require exclusion. For management, the strongest evidence lies with activity modification, therapeutic exercise, and foot orthotics as described, so incorporation of these should be at the forefront of an intervention plan. With an informed knowledge of how to craft the rehabilitation program for these patients, physical therapists can maximize improvements in pain and function to allow patients to defeat the limitations brought on by PFPS.Appendix A- Anatomical ReviewFigure 1: The illustration below shows the relevant anatomy of the anterior knee, with structures that attach to and stabilize the patella. This image is reproduced from Dixit S, et al., 2007.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5Figure 2: The image below shows force vector angles of each component of the quadriceps, as related to their fiber orientation and attachment site on the patella. This image is reproduced from Waryasz and McDermott, 2008.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors.","id":"4540589","page":"9","type":"article-journal","volume":"7","author":[{"family":"Waryasz","given":"Gregory R"},{"family":"McDermott","given":"Ann Y"}],"issued":{"date-parts":[["2008","6","26"]]},"container-title":"Dynamic medicine : DM","container-title-short":"Dyn Med","journalAbbreviation":"Dyn Med","DOI":"10.1186/1476-5918-7-9","PMID":"18582383","PMCID":"PMC2443365","citation-label":"4540589","Abstract":"BACKGROUND: Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS. METHODS: A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome. RESULTS: Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50-60% intensity. CONCLUSION: To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program.","CleanAbstract":"BACKGROUND: Patellofemoral Pain Syndrome (PFPS), a common cause of anterior knee pain, is successfully treated in over 2/3 of patients through rehabilitation protocols designed to reduce pain and return function to the individual. Applying preventive medicine strategies, the majority of cases of PFPS may be avoided if a pre-diagnosis can be made by clinician or certified athletic trainer testing the current researched potential risk factors during a Preparticipation Screening Evaluation (PPSE). We provide a detailed and comprehensive review of the soft tissue, arterial system, and innervation to the patellofemoral joint in order to supply the clinician with the knowledge required to assess the anatomy and make recommendations to patients identified as potentially at risk. The purpose of this article is to review knee anatomy and the literature regarding potential risk factors associated with patellofemoral pain syndrome and prehabilitation strategies. A comprehensive review of knee anatomy will present the relationships of arterial collateralization, innervations, and soft tissue alignment to the possible multifactoral mechanism involved in PFPS, while attempting to advocate future use of different treatments aimed at non-soft tissue causes of PFPS.METHODS: A systematic database search of English language PubMed, SportDiscus, Ovid MEDLINE, Web of Science, LexisNexis, and EBM reviews, plus hand searching the reference lists of these retrieved articles was performed to determine possible risk factors for patellofemoral pain syndrome.RESULTS: Positive potential risk factors identified included: weakness in functional testing; gastrocnemius, hamstring, quadriceps or iliotibial band tightness; generalized ligamentous laxity; deficient hamstring or quadriceps strength; hip musculature weakness; an excessive quadriceps (Q) angle; patellar compression or tilting; and an abnormal VMO/VL reflex timing. An evidence-based medicine model was utilized to report evaluation criteria to determine the at-risk individuals, then a defined prehabilitation program was proposed that begins with a dynamic warm-up followed by stretches, power and multi-joint exercises, and culminates with isolation exercises. The prehabilitation program is performed at lower intensity level ranges and can be conducted 3 days per week in conjunction with general strength training. Based on an objective one repetition maximum (1RM) test which determines the amount an individual can lift in good form through a full range of motion, prehabilitation exercises are performed at 50-60% intensity.CONCLUSION: To reduce the likelihood of developing PFPS, any individual, especially those with positive potential risk factors, can perform the proposed prehabilitation program."}]9Appendix B- Etiological FactorsFigure 1: The image below demonstrates the lines created by bony landmarks that are used to determine Q-angle. An increased Q-angle has been implicated as a risk factor for PFPS. This image is reproduced from Juhn MS, 1999.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral Pain Syndrome: A Review and Guidelines for Treatment","id":"4540680","page":"2012-2018","type":"article-journal","volume":"60","issue":"7","author":[{"family":"Juhn","given":"Mark S."}],"issued":{"date-parts":[["1999","11","1"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","citation-label":"4540680"}]11Appendix C- Assessment and DiagnosisFigure 1: The image below shows the patella with a lateral glide, lateral tilt, and a combination of both in comparison to a normally oriented patella. Lateral glide and/or tilt is commonly found in PFPS. This image is reproduced from Collado and Fredericson, 2010.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Patellofemoral pain syndrome.","id":"1488197","page":"379-398","type":"article-journal","volume":"29","issue":"3","author":[{"family":"Collado","given":"Hervé"},{"family":"Fredericson","given":"Michael"}],"issued":{"date-parts":[["2010","7"]]},"container-title":"Clinics in sports medicine","container-title-short":"Clin Sports Med","journalAbbreviation":"Clin Sports Med","DOI":"10.1016/j.csm.2010.03.012","PMID":"20610028","citation-label":"1488197","Abstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved.","CleanAbstract":"Patellofemoral pain (PFP) syndrome is a frequently encountered overuse disorder that involves the patellofemoral region and often presents as anterior knee pain. PFP can be difficult to diagnose. Not only do the etiology, diagnosis, and treatment remain challenging, but the terminology used to describe PFP is used inconsistently and can be confusing. Patellofemoral pain syndrome (PFPS) seems to be multifactorial, resulting from a complex interaction among intrinsic anatomic and external training factors. Although clinicians frequently make the diagnosis of PFPS, no consensus exists about its etiology or the factors most responsible for causing pain. This article discusses the pathophysiology, diagnosis, and management of PFP.Copyright 2010 Elsevier Inc. All rights reserved."}]20Figure 2: The illustration below demonstrates the performance of the patellar tilt test. Decreased ability to bring the lateral border to a neutral height relative to the medial border is a positive result. This image is reproduced from Dixit S, et al., 2007.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5Figure 3: The illustration below shows the path of the patella when excessive lateral forces create the “J” sign during knee extension. This image is reproduced from Dixit S, et al., 2007.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5Figure 3: The table below summarizes common knee pathologies that may present similarly to PFPS, with PFPS included for reference. This image is reproduced from Dixit S, et al., 2007.ADDIN F1000_CSL_CITATION<~#@#~>[{"title":"Management of patellofemoral pain syndrome.","id":"612577","page":"194-202","type":"article-journal","volume":"75","issue":"2","author":[{"family":"Dixit","given":"Sameer"},{"family":"DiFiori","given":"John P"},{"family":"Burton","given":"Monique"},{"family":"Mines","given":"Brandon"}],"issued":{"date-parts":[["2007","1","15"]]},"container-title":"American Family Physician","container-title-short":"Am Fam Physician","journalAbbreviation":"Am Fam Physician","PMID":"17263214","citation-label":"612577","Abstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence.","CleanAbstract":"Patellofemoral pain syndrome (PFPS) is the most common cause of knee pain in the outpatient setting. It is caused by imbalances in the forces controlling patellar tracking during knee flexion and extension, particularly with overloading of the joint. Risk factors include overuse, trauma, muscle dysfunction, tight lateral restraints, patellar hypermobility, and poor quadriceps flexibility. Typical symptoms include pain behind or around the patella that is increased with running and activities that involve knee flexion. Findings in patients with PFPS range from limited patellar mobility to a hypermobile patella. To confirm the diagnosis, an examination of the knee focusing on the patella and surrounding structures is essential. For many patients with the clinical diagnosis of PFPS, imaging studies are not necessary before beginning treatment. Radiography is recommended in patients with a history of trauma or surgery, those with an effusion, those older than 50 years (to rule out osteoarthritis), and those whose pain does not improve with treatment. Recent research has shown that physical therapy is effective in treating PFPS. There is little evidence to support the routine use of knee braces or nonsteroidal anti-inflammatory drugs. Surgery should be considered only after failure of a comprehensive rehabilitation program. Educating patients about modification of risk factors is important in preventing recurrence."}]5ReferencesADDIN F1000_CSL_BIBLIOGRAPHY1. Lin F, Wilson NA, Makhsous M, et al. In vivo patellar tracking induced by individual quadriceps components in individuals with patellofemoral pain. J Biomech 2010;43(2):235-241. doi:10.1016/j.jbiomech.2009.08.043.2. 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