SportsEngine



Ortho Study Guide-Quiz 2Meniscus TransplantationMeniscal Surgical HistoryPrior to knowledge of the vital function of the menisci--- they were routinely resectedThis led to predictable development of degenerative changes in the jtSubsequently preservation of the menisci tissue has been a main goal of surgeryAn alternative procedure: Mensical TransplantationMen. Transplant. Is an alternative for the young pt who has degenerative changes in the knee 2 prior total menisectomyStructure and FunctionMenisci are intracapsular fibrocartilaginous structuresStructure: Consists of water, collagen, and proteglycans--75% type 1 collagen--- great tensile strengthArranged in a circumferential patternPlays critical role in load transmission. With weight bearing- the load is transmitted to the menisci causing them to extrude. Circum. Orientation of the fibers resists this causing the strain to bear as hoop stresses. Disruption of the fibers leads to loss of this function.FunctionsDistributes weigh over a large surfaceIncrease jt congruencyProvide shock absorptionActs as a solid lubricantShapes and Sizes of the MenisciMedial Meniscus- Shaped like a capital CBears 50% of the load in the medial compartmentAttachments Ant. intercondylar area to post. Intercondylar areaTibial collateral ligamentCoronary ligament attachs to tibiaTransverse ligamentMore securely attached compared to lat. MeniscusLateral Meniscus- shaped like a lowercase oBears 70% of the load in the lateral compartmentAttachmentsLateral intercondylar area to lateral intercondylar eminencePopliteus tendon attached to post. Horn of meniscus to avoid impingementCoronary lig attaches to the tibiaTransverse ligamentMeniscus MovementsDuring flex-ext: Both menisci move post. Lateral is displaced more than medial Menisci prevent the jt capsule from entering the jtLocking Mechanism of the jt into close packed position. They direct the femoral articular condylesCoronary ligs tend to be looser on the lat. side--- contributes to the inc mobility in the lat meniscus Meniscal TearsCan be classified by location or patternLocationRed-Red: Greatest vascularity and best healing potentialRed-White: Near the peripheral margin but a suboptimal blood supplyWhite-White: Neither side demonstrates vascularityPatternsLongitudinal- “Bucket-handle”Horizontal Cleavage- “Parrot beak”ObliqueRadialComplexDegenerativeDemographicsYoung athlete- cause of injury by high energy mechanism>40 yrs old- degenerative tears with no recollection of traumaSigns and SymptomsTears may or may not be symptomaticSymptoms include:Clicking and pain with activityVMO atrophyPain with or without swellingLocking and UnlockingJt line tendernessBlocking at end rangesGiving wayPositive Diagnostic and Specials testsMcMurray, Apleys, Andersons Med-Lat GrindIndications for TransplantationYoung pt (<50) symptomatic after menisectomy (not age appropriate for total knee)Concomitant procedure to ACL reconstruction in medial meniscus deficient kneePrior total menisectomy with articular cartilage degeneration and pain2mm or more of tibiofemoral jt space on 45 weight bearing posteroanterior radiograph is necessary for txContraindications of TransplantationMalalignmentVarus or Valgus deformitiesFoal chondral defectsLigament InstabilityAdvanced arthritisFemoral flatteningConcavity of Tibial PlateauOsteophytes ObesityRAInfectionLack of commitment to postoperative restrictionsMuscular AtrophyRehabilitation ProgramGoal: To prevent excessive weight-bearing forcesControl high compressive and shear forcesImmediately post-opPt placed in hinged long-leg brace for 6 wksIn 0 to 90 flex during rehabLocked in full ext for 4 wks unless otherwise indicatedPatellar mobs in all directionsPROM, AROMStretching of hams, gastrocQuad re-educationCryotherapy 6-8 x a day 15-20 minsPt is placed on crutchesFirst 4 wks TTWB, FWB by 6 wksWeeks 0-6By week 6 FWB. ROM 90 -135Hamstring curls, knee ext, hip add/abd, weight shiftingProgressively add exercises every 2 wks. Weeks 6-14Should have full ROM by week 8-14Quad and IT band flexibility exercises addedWeight bearing exercises beginCardiovascularStationary bike, Walking in water, Swimming and walking on land (9th week)Weeks 14-22Resistance Exercises are addedCardiovascular: stair climbing machine Week 20-30Squat to 90Running is permitted. Progress to crossover maneuversOutcome MeasurementsTesting effectiveness, functioning, and integrity of mensical transplant Subjective AssessmentsROMPalpationSpecial TestsImagingHistologic AnalysisArthroscopyMain Reasons for Transplant FailureCoexisting Degenerative DiseaseLimb Malalignment: places uneven pressure on the involved compartmentProcedure to prevent this: combined osteotomy-mensicus transplantSummaryMeniscus is critical to knee stability, mobility, and integrityIf compromised jt degeneration is inevitable, and due to poor vascularization surgery is often indicatedTransplantation is an effective alternative for the young pop. with a h/o menisectomySurgical techniques: Double Bone Plug & Single Bone BridgeRehab is similar to repair but with slower progression of activityStudies have shown that pt have pain relief and inc function and meniscal transplants have survival of nearly 75% at 10 years. Beyond 10 yrs is inconclusiveEven after appropriate surgery and rehab pts will not be able to return to high level athletics.Magnetic Bone Stimulators for Fusion of Persistent Non-UnionsExternally applied flexible therapeutic magnetsMagnetic field too small to influence tissueDo not influence healing speedDo not influence tissue temperatureBone Stimulator- Produces a magnetic field capable of influencing tissue growth. Can be internal or external.Increased healing percentages esp. when at high risk for non-unionBone stimulators do NOT increase the speed of healingProphylaxis of non-union1). Causes of non-unionImproper position/pseudoarthrosisImproper or insufficient immobilizationInfectionPresence of soft tissue interposed btw the edges of fractured boneInadequate blood supplyPoor nutritional statusMetabolic bone diseaseSpecific pathologyFactors determining high risk for non-unionTobacco useOlder ageSevere anemiaDiabetesAnti-inflammatory drugsSteroidsInfectionPoor vascular supplyTypes1). Surgically Implanted Electrodes 2). Externally Fixated Electromagnetic AmplifiersDirect CurrentPulsed Electromagnetic Field (PEMF)Extracorporeal Shock Wave Therapy (ESWT)Interference Current (IFC)DiathermyHistory of Bone Stimulators:Surgically Implanted DevicesMagnetsImplanted ElectrodesInfection Risk Removal SurgeryE-Stim across fracture siteOpen CastingsHow do Bone Stimulators Work?Bone growth effected by 3 physical strategies:Mechanical StimulationLow intensity ultrasound (studies have conflicting results, quality of evidence is questionable, and use in clinical practice is unsupported)Electromagnetic fieldsBiochemistry Involved:Wolff’s Law: Bone growth effected by stressorsIncreased stress -> Osteoblastic activity-> Increased cortical thicknessDecreased stress-> Osteoclastic activityNWB status inhibits bone growthResearch proves bone is Piezoelectric: Charge separation produced by stressTension causes a + charge formation :Osteoclastic activityCompression causes a – charge formation: Osteoblastic activityElectromagnetic fields can influence polarity/membrane potentialsHall effect- electromotive force that causes charged particles to accumulate with like charges in the presence of a magnetic fieldResisting the motion of charged particles in the bloodstream by magnetic polar inductance induces friction which causes a thermal effectIncrease in temperature causes vasodialationMagneto hydrodynamic effect- Increased delivery of molecular oxygen for cellular metabolism and reduction of secondary tissue hypoxia.Bone Stimulator Biochemistry:Hypothesized mechanism:Increase Osteocyte activityIncrease blood flowIncrease O2 exchangeFocal ApplicationElectromagnetic fields:alter the effects of hormones on the cell membranesincrease production of growth factors and receptorsaffect calcium flux across membranesstimulate endothelial cell proliferation and capillary formationElectromagnetic fieldsAny flow of electric current produces an electric fieldTypes of electric currentDirect currentAlternating currentPEMFIFCESWTMost are too small to effect bone growthBone stimulators are basically amplified magnetic fields1.) Direct CurrentCathode is place percutaneously at fx site and anode is placed on the skinImmobilization and NWB status is prolonged and therefore a drawbackConstant direct current is applied for 12 weeksDirect current study concluded that bone stimulators may be very effective in achieving union in fractures that have persistent infection (86%)2.) Interference Current Uses capacitive coupling stimulatorsInterference currents are pulsed using surface electrodesInterference current study showed that electrical capacitive coupling is notably effective in achieving union in fxs that have previously not healed. It also shows the versatility of the treatment (different sites were used)Extracorporeal Shock Wave Therapy (ESWT)Non-Invasive procedure using high energy shockwaves for healing non union fracturesShockwave energy is carefully positioned in the plane of the fracture and the total energy from different directions is divided into equal parts ranging from 2-24 directionsESWT study showed 75.7% successful healing ratePulsed Electromagnetic Field (PEMF)Non-Invasive e-stimInductive Coupling stimulator is a unit that produces a pulsed field which is fixed to a plaster cast and can be plugged into a standard home outletTx is 10 hours daily for 12 weeks while pt. remains NWBA report from 1981 showed PEMF had an 87% success rate healing 127 cases of non union tibial fxsAnother study looked at PEMF for congenital pseudarthrosis of the tibia and showed favorable results for type I and type II non-unionsA meta analysis suggested that current evidence is insufficient to conclude a benefit of EMS in improving the union in fresh fx, osteotomy, delayed union, or non union. Also not sufficient to conclude decreased time to healing in tibial fxs, or reducing pain in these patients.*Another study looked at effectiveness of strong magnetic field bone stimulators and showed that SMF has the potency to stimulate bone formation and regulate its orientation.Bone stimulators and insurance coverageSome insurance companies mandate bone stimulation as a standard of care in order to qualify for reimbursement. Conditions requiring this include the following:Previous non-unioned fxgrade III or worse spondylolisthesisfusion performed at more than one levelcurrent smoking habitdiabetesrenal diseasealcoholismSynthesisElectromagnetic fields are an appropriate and effective treatment for persistent non union fracturesCan be used with or without bone grafts as long as the fx site is immobilizedResearch showed a range of healing times, but regardless healing was completeThere was inconsistency between the meta analysis and previously published research (perhaps due to extensive inclusion criteria for meta analysis)PT Conclusion: PT may be responsible for:Instruction for use / HEPOrdering infoD/C planningAdherenceDocumentation/InsuranceMicrofracture Surgery of the KneeWhat is microfracture surgery? Surgical reparative technique that induces healing to occur in area of articular cartilage damageMFS of subchondral bone is a bone marrow stimulation technique for the tcx of chondral defectsCan be performed on a variety of jtsArticular Cartilage Composed of water, cells, matrix—contains type 2 collagen fibersHelps in distributing loads across the knee jt Reduces stress on subchondral bone and minimizes frictionAvascular and Aneural- therefore if left untreated have little or no potential to heal spontaneouslyAreas of MFS (Knee)Medial femoral condyleLateral femoral condyleTibial plateauTrochleaPatellaCombo of any aboveCandidates for MicrofractureAthletes Pts who present with unilateral or bilateral knee painElderly arthritic pts who are still active Goals of MFSAlleviate painMaximize functionDelay degenerative changesIndicationsFocal traumatic chondral defectsDegenerative lesionsUnipolar or Bipolar lesionsDefects size <4 cmCartilage lesionsFocal grade 3 or 4 articular surface lesions without bone loss that are surrounded by normal cartilageRelatively short pre-op duration of symptomsOptimal pt age <45Relative ContrindicationsSignificant subchondral bone lossMechanical axis malalignment of the kneeBipolar lesionsHigh risk of noncompliance with post-op rehabDefect size > 4cmBMI >30Mensical deficiencyPt age >60Absolute ContraindicationsGeneralized degenerative jt changesLimited pt complianceUncontained chondral lesionsSevere axial malalignment >5 Patellar mal-tracking or instability for pf lesionsHigh grade lig instabilityTumorInfectionInflammatory arthropathySystemic cartilage disordersRisks for MicrofractureBleeding & InfectionInc Stiffness & Cartilage BreakdownWhy MFS?Does not burn any bridges with regard to future surgical proceduresAllows for perforations to still be created while eliminating risk for thermal necrosisSurgeon is able to better assess areas of articular surfaceDisadvantages of MFSTissue is composed of type 1 collagen rich fibrocartilage which does not resist compression and shear loads Post Op RehabIMPORTANTDepends on the location of the chondral defectNWB 4-6 weeks to allow cartilage to healUse of CPM machine to prevent arthofibrosis and allows the defect to heal properlyConclusionsDemonstrated effective forSome athletesIndividuals <40 Individuals with osteonecrotic kneesAnimalsFemoral condylesDemonstrated uneffective forIndividuals >40 Chondral defects > 2cmSome Athletes The Anterior Cruciate LigamentActs as the primary restraint to anterior tibial translation and guides the screw home mechanism associated with TKE. One of the most commonly injured ligaments in the knee; predominantly in young athletesAfter injury, the chance of meniscal injury and osteoarthritis rises sharplyACL Stats:Occurs in about 1 of 3000 pplOver 100,000 injuries occur from skiing per year in the USA Cost management is approx 2 billion annuallyFemales at higher risk, possibly due to:Larger Q-angleIncreased joint laxityUneven muscle activationDifferent cutting and landing patternsLess strengthHormonal Differences70% of injuries are from a non contact mechanism such as stopping, cutting, or side steppingRelevant AnatomyLigament is intrarticular but extrasynovialComposed of 3 main bundles: anteromedial, posterolateral, & intermediateLigament runs obliquely from tibia anteriorly and medially to the femur posteriorly and laterallyComposed of collagen fiber and elastinBlood supply from middle geniculate arteryAnatomy of the KneeIndications for SurgeryRecurrent effusions and instabilityAssociated meniscal injuryPatient is involved in more than 50 hours of high level activity annuallyPatients with translation greater than 7mmContraindications for SurgeryInfectionSoft-tissue abrasionPt. reluctant to participate in rehabilitationLess than 2 weeks from injuryLow activity levelsOsteoporosisSkeletal ImmaturityInflammatory arthropathyPostoperative ACLUp to 170% strength of original ACLAround 4 weeks, 10% strength of original ACLCellular repopulation and revascularization can take upto 24 weeks. Reorganization can take upto 32 weeksPostoperative collagen cannot withstand tensile stressCyclic loading can positively impact the remodeling process by helping fibers realign. This increases knee stability and improves kinematicsKnee Bracing PostoperativelyProvides mechanical stress protection of the graftPermits motion through modified arcsMay protect graft from low level cyclic stressMay assist kinematic guidance of the remodeling graftMay increase proprioception to the lower extremityInhibits anterior translation through levelPsychological AspectsMost widespread + effects are from anecdotal evidencePt’s report increased sense of security and stability and a sense of improved functional performancePt’s have desire to rehab faster and more aggressivelyBe aware of the above and follow precautions of the repairProprioceptive benefits may only be due to cutaneous contactCadaver StudiesAllows direct measure of ligament strain in anatomical rangeAdvantage- Lack the tension of living soft tissues , therefore effects in vivo may be more effectiveDisadvantage- The axial tissues of the limb do not respond to the contact of the knee braceStudiesshort term post op bracing is beneficial to the patient’s sense of recovery and confidence, however a lengthened use could lead to adverse effectsthat there are no detrimental effects of post op knee bracing, however, after 3 months, counterproductive results were observed. Also, patient specific brace selection should be used considering: principal role of the brace, nature of the instability, specific morphologic or physiologic requirements, neurovascular conditions, or patient goals.Controversial IssuesCustom vs. Off the shelfOne study showed no difference in efficacyRestriction vs. no restriction of rotation of the knee Effect on proprioceptionBracing Trends Amongst Physicians (survey was completed)Bracing among MD’s has been less frequentWith ACL deficient patients, 35% of doctors brace 20% of the timeWith ACL reconstructed patients, 31% of doctors brace 81-100% of the timeMD’s base brace rx on amount of activity of the pt.Most prescribed brace is Don JoyWhen are functional braces used?With discovery of ACL deficiency of following traumaUsed for general stabilization and to prevent anterior forces of the tibia on the femurMost studies done look at effects braces have on proprioception, muscle dynamic stability, and tibial translationProprioceptionMechanoreceptors have been found specifically in the ACL that assist in knee proprioceptionTherefore, it is speculated that with ACL injury, proprioception is effectedCompare both sides by testing threshold of passive knee motion?Study found that threshold of passive knee motion was impairedStudy also showed that brace did not improve the thresholdDynamic StabilityStrengthen hamstrings, quads, and gastroc to prevent anterior translationHamstrings are esp imp to prevent ant. translation during gaitStudy shows that braces decrease muscle performance but increase stabilityAnother study shows that brace dependency may be detrimental to hamstring strength.Symptoms of the chronic ACL deficient kneeDiscomfortSwellingWeaknessGiving outRadiograph abnormalitiesChanges in muscle recruitment timeRule of 3 for ACL injuries1/3 will compensate adequately and be able to participate in recreational activities1/3 will be able to compensate but will have to give up significant activities1/3 will do poorly and prolly require reconstructive therapyNon operative managementE-stim with leg curls and leg pressTreadmill running, stationary cycling, sliding board traininghalf-speed agility skill trainingunopposed practice of sport specific skillsopposed practicefull with teamNon operative summaryLimited success for those participating in high level physical activity23%-39% success rate for returning patients back to high levels of activity ................
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