Mechanics of Tissue & Healing



Mechanics of Tissue & Healing

Force & Its Effects

When a force I sustained by the tissues of the human body,

2 primary factors help to determine whether injury results:

1) size or magnitude of the force, and

2) the material properties of the involved tissues

Load - Deformation Curve - shows the deformation of a structure in response to progressive loading/ force application.

Within the elastic region of the load deformation curve, the

greater the stiffness of material = the steeper the slope of the line.

( Increase Stiffness = Decrease Under Load)

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Yield Point (elastic limit): the max load that a material can sustain without a permanent deformation

Failure: loss of continuity; rupturing of soft tissue or fracture of a bone

Injury Classification

Contusion: a compression injury involving the accumulation of blood & lymph within the muscle

Strain: tearing injury to a tendon/ muscle

Sprain: tearing injury to a ligament

Note: tendons are about 2x as strong as muscles to which they are attached

Classifying Injuries:

1st Degree:

- pain, micro tearing of the fibers, no readily observable symptoms.

- may have mild discompfort/ pain, localized swelling, tenderness, mild edema & ecchomyosis

- causes little/ no restrictions to ROM therefore no loss of function

2nd Degree:

- more severe pain, more extensive rupturing of tissue

- more noticeable discomfort/ pain, greater localized swelling, tenderness, edema & ecchomyosis

- detectable joint instability and/ or muscle weakness cause noticeable reductions in ROM

3rd Degree:

- severe pain, & major loss of continuity

- severe discomfort/ pain, significant localized swelling, tenderness, edema & ecchomyosis

- causes severe restrictions to ROM due to complete instability of the joint

Note: Complete ruptures of tendons will result in the muscle curling up into a ball. This complete rupture can actually result in less pain compared to a severe tear. A rupture requires corrective surgery to repair.

Soft Tissue Injuries: (muscles, tendons, & ligaments)

- when a tendon/ ligament tears, the replaced tissue is a fibrous mesh of scar tissue that is significantly less elastic than the tendon/ ligament

- severe injuries may result in the muscle regaining only 50% of its pre-injury strength

- tendons & ligaments can take more than a year to heal, often becoming elongated & unstable after the injury

Bone Injuries:

- the bone is strongest in resisting compression forces & weakest in resisting shear forces. The bone is also stronger in the resisting compression than tension forces.

(I) Simple -bone ends remain intact with the surrounding soft tissues

(II) Compound - one or both ends of the bone protrude from the skin

Nerve Injuries:

Central Nervous System - brain & spinal cord

Peripheral Nervous System - 12 pairs of cranial nerves & 31 pairs of spinal nerves, along with their branches

- when a nerve is completely severed, healing doesn’t occur and the loss of function is typically permanent. Surgery may be an option in some cases.

Many other injuries include: cramps, spasms, myositis, fascitis, tendinitis, tenosynovitis, myositis ossificans, calcificans, calcific tendinitis, bursitis....

Stages of Healing & Repair

A. Acute Inflammatory Response Phase (Reactive Phase)

- occurs for the first several days following the injury

- characteristics of inflammation include: redness (ecchomyosis), local heat, swelling (edema), pain and potentially loss of function

- phase begins with vasoconstriction (seconds to 10 mins).

- this reduces the loss of blood and allows the initiation of clotting (platelets), BUT causes hypoxia which can lead to necrosis (tissue death)

- next, vasoconstriction results in swelling due to increased blood flow

B. Repair & Regeneration Phase ( Fibroblastic Phase)

- this phase overlaps the acute phase and lasts 2 days through the next

6-8 weeks

- begins when the hematoma’s size has decreases enough to allow room for growth of new tissue

- by the 4th- 5th day following the injury, a weak , nonvascular connective scar tissue has been produced over the injury

- scar tissue is a fibrous, inelastic, non vascular tissue that is less strong and functional than the original tissue

C. Remodeling Phase (Maturation Phase)

- the phase begins about 3 weeks post-injury, over lapping the Repair & Regeneration phase, and continues for a year or more.

- involves the maturation of the tissue, decreased cellular activity, increased tissue organization, and return to normal chemical activity

- the collagen fibers continue to realign to the forces of biomechanical stress that they are subjected to

(HENCE, the IMPORTANCE of EARLY MOVEMENT)

Concussions

Definition:

A concussion is a significant blow to the head that may result in unconsciousness.

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Signs & Symptoms

Emergency Signs:

- Persistent unconsciousness (coma) - Repeated vomiting

- Altered level of consciousness - Unusual eye movements

(drowsy, hard to arouse, or similar changes) – Unequal pupils

- Persistent confusion - convulsions

- Gait or walking abnormalities - Muscle weakness on one/ both sides

- Convulsions - Amnesia of events surrounding injury

Signs of a Serious Injury

- A bad headache that gets worse or doesn’t go away within the first 4 - 6 hours after the injury occurred.

- Drowsiness, if it lasts more than 2 hours, or if the person is difficult to wake up. A certain amount of drowsiness is very common after a head injury, especially in younger children.

- Confusion & disorientation.

- Feeling sick or actually vomiting is common following a head injury, but if it is persistent or appears to be getting worse, it could be serious.

Effects of concussion:

- Headaches that don’t follow any particular pattern, though they may worsen towards the end of the day.

- Loss of concentration with a poor attention span, such as a person loses track of conversations, films or books.

- Loss of memory. After a significant concussion, people will usually be unable to recall the event of injury and the period after it. They may also find that their memory for recent events may be impaired.

- The person’s personality may be altered. Most commonly they may be irritable or short tempered.

- There may be other specific problems, such as loss of sex drive/ appetite, general apathy/ disinterest in life and a lack of self-esteem and self-confidence.

|It is quite common for an individual to experience 1-2 of these symptoms after a relatively minor head injury, but rarely all of them |

|together. |

Causes & Risks:

A concussion may result from:

1) a fall in which the head strikes against an object or a moving object strikes the head.

2) Significant jarring in any direction can produce unconsciousness.

It is thought that there may be microscopic shearing of nerve fibers in the brain from the sudden acceleration or deceleration resulting from the injury to the head.

The level of unconsciousness may relate to the severity of the concussion. Often victims have no memory of events preceding the injury or immediately after regaining consciousness with worse injuries causing a longer period of amnesia.

Often the max memory loss occurs immediately after the injury with regaining of some memory function as time passes. Complete memory recovery for the event may not occur.

Complications include:

- Intracerebral hemorrhaging ( results in a stroke)

- Brain Injury

Bleeding into or around the brain can occur with any blow to the head, whether or not unconsciousness occurs, If someone has received a blow to the head, observe closely for signs indicating possible brain damage.

Diagnosis:

Grade1: no loss of consciousness, with symptoms lasting less than 15 minutes (90%)

Grade 2: no loss of consciousness, with symptoms lasting more than 15 minutes (10%)

Grade 3: any loss of consciousness

A neurological examination may show abnormalities.

Tests that may be performed include:

- Head CT

- MRI of the Head Treatment:

- An initial "baseline" neurological evaluation

- If a blow to the head during athletics leads to unconsciousness, a trained person must determine readiness for continued participation and timing for return to play. (See Table 1)

- Concussion complicated by bleeding or brain damage must be treated in a hospital

- After recovery, the player’s chance of suffering another concussion may be 4x as high as that of a player who has never had a concussion.

Second Impact Syndrome: a rapid, fatal brain swelling that may occur if a person suffers another head impact, even if a minor one, before the symptoms of a previous concussion have fully cleared.

Punch Drunk Syndrome: repeated concussions could cause cumulative, neurological damage, like punch “drunk syndrome” seen in boxers

Prognosis:

- Full recovery is expected from an uncomplicated concussion, although prolonged dizziness, irritability, headaches, and other symptoms may occur

- Most post concussion symptoms disappear in time. This may take up to 6 months - 1 year. Very rarely it may take longer.

- The doctor may refer them to see a clinical psychologist of the patent is having difficulty coping.

Prevention:

Attention to safety, including the use of appropriate athletic gear, such as helmets, reduces the risk of head injury.

Glasgow Coma Score

The GCS is scored between 3 and 15, 3 being the worst, and 15 the best.

It is composed of three parameters :

|Best Eye Response. (4) |Best Verbal Response. (5) |Best Motor Response. (6) |

|1) No eye opening. |1) No verbal response |Ex 1) No motor response. |

|2) Eye opening to pain. |2) Incomprehensible sounds. 3) Inappropriate |t 2) Extension to pain |

|3) Eye opening to verbal command. |words. |3) Flexion to pain. |

|4) Eyes open spontaneously. |4) Confused |4) Withdrawal from pain |

| |5) Orientated |5) Localizing pain. |

| | |6) Obeys Commands. |

Note that the phrase 'GCS of 11' is essentially meaningless, and it is important to break the figure down into its components, such as E3V3M5 = GCS 11.

A Coma Score of:

- 13 or higher correlates with a mild brain injury

- 9 to 12 is a moderate injury

- 8 or less a severe brain injury.

Teasdale G., Jennett B., LANCET (ii) 81-83, 1974.

Examples of Differing Concussion Classification Systems and Return to Play Recommendations

Guidelines of Robert C. Cantu, MD

|Severity |1st Concussion |2nd Concussion |3rd Concussion |

|Grade 1 (mild) |May return to play if |May return in 2 week if asymptomatic for 1 |Terminate season; |

| |asymptomatic |week prior |may return next year if |

| | | |asymptomatic |

|Grade 2 (moderate) |Return in 1 week if asymptomatic|Wait at least 1 month; may if asymptomatic |Terminate season; |

| | |for 1 week prior; consider terminating season|may return next year if |

| | | |asymptomatic |

|Grade 3 (severe) |Wait at least 1 month; may if |Terminate season; | |

| |asymptomatic for 1 week prior |may return next year if asymptomatic | |

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On Site Sport Injury Assessment:

Why is it Important of Accurately Assess an Injury?

- To reduce complications

- Reduce the time needed for rehabilitation

- Reduce the loss of income

Primary Survey for Trauma

- stabilize head & neck

- check A,B & Cs

A - Airway

B - Breathing

C – Circulation

- in the case of potential spinal injury(fall skiing, hit in hockey/ rugby), the individual should be immobilized until a professional has properly diagnosed that there is no chance of a spinal injury

- if helmet is worn, remove the facemask, but do not remove the helmet or chin strap itself

- determine the initial level of consciousness using the:

Glasgow Coma Score

Note: The patient with cold pale peripheries has shock until proved otherwise

Secondary Assessment:

Use the acronym “SALTAPS” when completing a secondary assessment

S - SEE the initial injury

A - ASK for the history/ mechanism of the injury

(How did it happen? Is this an acute or chronic injury?)

L - LOOK for signs of edema, deformity, ecchymosis, atrophy

T - TOUCH - (palpation) for tenderness, pain, swelling, etc

A - ACTIVE MOVEMENT TEST

- ask what is the pain free ROM the player can do voluntarily**

P - PASSIVE MOVEMENT TEST

- trainer/ therapist moves the player’s injury passively**

S - STRENGTH - the trainer resists the movement of the injured area.

If the injured area responds well to all of these tests, then functional weight bearing tests can be carried out in increasing difficulty.

After fractures/ dislocations have been ruled out, soft tissue structures (ligaments, muscles, bursa, joint capsule) are assessed using special tests which includes:

Range of Motion Tests: Active + Passive (end feel), + Resisted

Neurological: Dermatomes, Reflexes

Stress Tests: Ligaments, Joint Capsule Stability, Impingement Signs, Muscle Balance

Functional Tests: Proprioception, Sport Specific Skills (strength, power, agility)

Note: **comparing to other side is ideal for normal levels**

Palpation

Palpation is a method of feeling with the hands during a physical examination. The health care provider touches and feels the patient's body to examine the size, consistency, texture, location, and tenderness of an organ or body part.

When assessing an individual using a palpation exam, the examiner must:

1. First get permission to touch

2. Clean hands or use gloves

3. Palpation should start with gentle, circular movements moving bilaterally towards the injury

Signs of injury can include:

- Temperature differences

- Swelling

- Point tenderness

- Crepitus

- Deformity

- Muscular spasm

- Cutaneous sensation

- Pulse

Knee Joint

Intro:

If you've ever injured your knee, you're not alone. One of the main reasons they're common is that with so many teens playing sports, knees can be overused, leading to several types of injuries, some of which can't be repaired. So what are some of these knee injuries and what can you do to prevent them?

- The knee is considered one of the most complex joints of the body

- One of the most traumatized

- Classified as a hinge joint (allowing flexion & extension)

- Extremely weak in terms of bony arrangements and therefore is compensated through ligaments and muscle support

What's in a Knee?

The knee is made up of several body parts like bones, cartilage, muscles, ligaments, and tendons, all working as one. So when we talk about a knee injury, it could be stress or damage to any of these parts.

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Bones and Cartilage

The knee sits in the middle of three bones:

- tibia - fibula - femur

- patella (protects the anterior aspect of the knee, and improves mechanical advantage of the quads by increasing the angle of insertion of the tibia)

Cartilage:

- Articular cartilage acts like a cushion and to keep the femur, patella, & tibia from grinding against each other.

Meniscus

- Improves the fit between the femur & the tibial condyle

- Wedges the cartilage that help provide a lubricated articular surface area & help absorb shock

- Each knee has two menisci - the inside (medial) meniscus and the outside (lateral) meniscus.

Bursae

- Fluid filled pouches of synovial fluid that act as additional shock absorbers and improve joint stability

Muscles

The muscles in the knee include:

- the quadriceps (vastus lateralis/ medius/ intermedius) & rectus femoris

-the hamstring (semimebranosis/ tendenosis, bicep femoris)

- sartorius - tensor facsia latae - gastronemius

Ligaments

- Ligaments are like cables of strong fibrous tissue that connect bones to bones or cartilage to bones. There are 4 ligaments in the knee that help connect the femur to the tibia and keep your legs stable:

1st Degree: Microscopic Tear

2nd Degree: Microscopic & Gross Disruption of Ligament Tears

3rd Degree: Complete Tear (surgically repaired)

Knee Sprains

A sprain means you've stretched or torn a ligament. Common knee sprains usually involve damage to the ACL and/or MCL. The most serious sprains involve complete tears of one or more of the knee ligaments. Symptoms of knee sprains include:

• a popping or snapping sound in the knee at the time of injury

• pain that seems to come from within the knee, especially with movement

• not being able to put any weight on that leg

• swelling

• fluid behind the kneecap

• the knee feels loose or unstable

Anterior curiae ligament (ACL)

- ACL connects your femur to your tibia at the center of the knee.

- ACL is responsible for preventing the tibia from sliding forward on the femur

- ACL is practically the only structure that controls the rotation in the knee, preventing the knee from buckling/ twisting

- ACL can be partially torn (stretched) or completely torn (ruptured)

- the ACL will not heal, and requires corrective surgery to repair

ACL tears are caused by:

- anterior blow to the knee

- twisting Varus force to the knee

(internal rotation of the tibia, & external rotation of the femur)

Injury most commonly occurs during cutting motions here the foot is planted, and the body suddenly twist in another direction.

- hyperextension of the knee

|[pic] |In medical terms, the ACL is the primary restraint to anterior displacement of |

| |the tibia on the femur. This means that when the ACL is injured, the shinbone can|

| |slide forward on the thighbone, causing the knee to "give way". |

"POP" = ACL Tear "SNAP" = FRACTURE

Note: Female athletes are at greater risk of tearing their ACL do to a greater Q angle of their hips.

Treatment:

- it is possible to return to sports as early s 4-6 weeks provided the sport does not involve any twisting or pivoting motions

- additional support (knee brace) is required for returning to sports involving pivoting

- even with a brace, full strength and mobility should be recovered before resuming any sports to ensure re-injury doesn't occur

Surgery:

- if the knee gives way despite rehab and wearing a brace, reconstructive Surgery may be needed (ligaments from the hamstring often used)

- after Surgery, there is a prolonged rehab period (up to 1 year)

- full activity to sport is usually possible

[pic]

[pic][pic]

Posterior Curiae Ligament (PCL)

- provides the central axis of rotation

- The PCL connects your femur to your tibia at the back of the knee.

- It helps control the knee's backward motion, like keeping the shinbone from sliding out under the thighbone.

- is vulnerable to injury after the ACL has been torn and the knee has been forced into hyperextension

PCL Tear Caused by:

- falling with the full weight on the anterior aspect of the knee, with the knee flexed at a 90 degree angle

- severe hyperextension (after the ACL has already been torn)

Treatment:

- the usual first aid (4 phases) administered

- Surgery may be warranted when there is instability

- strengthen the hamstrings minimize the risk of hyperextension

The Collateral Ligaments

Medial Collateral Ligament (MCL)

- the MCL connects your femur to your tibia along the inside of your knee

- it keeps the inner part of your knee stable and helps control the external rotation of the knee

- keeps the knee from bending inward - "knock knees"

Causes of a MCL Tear

- a severe valus force to the knee (femur internally rotates, while the tibia external rotates)

- a direct blow to the lateral aspect of the knee while the foot is planted (tackled from the side)

Lateral Collateral Ligament (LCL)

- the LCL connects your femur to your tibia along the outside of your knee.

- provides lateral support for the knee and helps control the sideways motion of your knee, like keeping it from bending outward.

Causes of a LCL Tear

- a direct blow to the medial aspect of the knee while the foot is planted (tackled from the side)

- severe varus force

Treatment:

- the 3 different sprains, each require a different rate of rehabilitation (all treatments require he 4 phases of rehabilitation)

Other Knee Injuries

Strains

- A strain means you've partially or completely torn a muscle or tendon.

- With knee strains, you may feel symptoms similar to a sprain and may see bruises around the injured area

Tendinitis

- "itis" = inflammation, therefore tendinitis is inflammation of a tendon

- it is often caused by overuse.

-a person with tendinitis might have pain or tenderness when walking, or when bending, extending, or lifting a leg.

Bursitis

- A bursa is a sac filled with fluid located near a joint.

- If a bursa in the knee becomes inflamed and swollen from overuse or constant friction, it can develop into a condition called bursitis.

- Symptoms include:

- warmth - tenderness

- pain on the front of the kneecap - swelling

Fractures and Dislocations

- a fracture is a cracked, broken, or shattered bone.

- you may have trouble moving that bone, there's likely a lot of pain.

- patellar dislocation happens when the patella is knocked off to the side of the knee joint

- usually it will need to be put back into place by a doctor.

Symptoms include:

- swelling and a lot of pain at the front of your knee.

- there will usually be an abnormal bulge on the side of your knee, and you may be unable to walk.

Meniscal Tears

- commonly referred to as torn cartilage

Causes

- combined loading & twisting

- degenerative tear with no history of an acute injury

- damage to the meniscus is a really common sports injury, especially in sports where sudden changes in speed or side-to-side movements can cause them to tear.

Diagnosis

- meniscal injuries often occur together with severe sprains, especially those involving the ACL.

- meniscal injuries can cause tenderness, tightness, and swelling around the front of the knee.

- sometimes fluid collects around the knee (this is called effusion)

- locking of the knee joint (a piece of meniscus is caught in the knee)

- localized pain may worsen by specific movements - bending & pivoting

Treatment

- if regular physiotherapy doesn't work & the knee remains locked, arthroscopic surgery may be required

Doctors Assessment

There are different things a doctor may do to figure out whether you have a knee injury. Treatment for a knee injury usually depends on the type of injury you have.

The Doctor Will:

- ask you questions about your symptoms

(what your usual activities are (types of sports you play))

- also want to know about other health conditions (osteoporosis)

- examine the different parts of your knee, checking the bones, ligaments, and tendons for any signs of injury.

- will probably bend, twist, and turn your knee to look for any signs of an unstable knee joint.

- ask patient to get off the exam table and walk, bend over, or squat so your doctor can get a better look at your knee

- sometimes an X-ray the knee will be taken

- a MRI/ CAT scan may also be recommended so doctors can get a better three-dimensional picture.

For injuries like mild sprains, strains, and overuse, resting your knee may be one of the first treatments your doctor recommends. Remember RICE:

• Rest

• Ice

• Compression

• Elevation

If your doctor recommends RICE, you should:

Rest, Ice, Compression, Elevation (Injury treatment)

- rest your knee as much as possible

- use ice packs for a couple of days to bring down swelling

- use compression (ACE) bandages, and elevate the leg on pillows

- doctor may prescribe anti-inflammatory meds

- use crutches which may involve using a brace/ cast for a few weeks or months

- for more serious knee injuries, your doctor might recommend you see an orthopedic surgeon

Note Other RICE Acronym is:

Rest, Immobilize, Cold, Elevate (First Aid, fractures)

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