Idea Transcript
Knee • Most injured joint in sports • Common site of osteoarthritis (OA)
Traumatic injuries
Knee • Three joints – Tibiofemoral joint – Patellofemoral joint – Superior tibiofibular joint
Repetitive injuries Both may lead to OA
Tibiofemoral Joint Anatomy • Convex femur on slightly slightly concave tibia • Resting position – Flexion = 20° 20°
• Close packed position – Full extension with tibial external rotation
Knee Kinesiology • Knee range of motion
Tibiofemoral Joint Anatomy • Capsular pattern – Gross limitation of flexion – Slight limitation of extension
• EndEnd-feels – Flexion = soft tissue approximation – Extension = ligamentous
Knee Extensors • Internal torque - angle relationship* relationship*
– Flexion: 0 - 140° 140° – Internal Rotation: 0 - 30° 30° (knee at 90° 90° of flexion) – External Rotation: 0 - 40° 40° (knee at 90° 90° of flexion) – No rotation with knee in full extension
* Ability of the muscles to generate torque
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KNEE JOINT MCLMCL-LCL Injuries
Knee Flexors • Internal torque - angle relationship* relationship*
* Ability of the muscles to generate torque. That relationship exists regardless of the position of the plane of movement or orientation orientation of the body.
Knee ligaments • Medial collateral ligament (MCL) – Narrow, thick, superficial palpable layer – Broad, thinner, deep layer blending with the joint capsule – Provides medial stability to the knee
Knee ligaments • Medial collateral ligament (MCL)
Knee ligaments • Medial collateral ligament (MCL) – Superficial • From medial epicondyle of the femur to the tibia • Proximal to distal (posterior to anterior)
– Deep • Broader/capsular • Anterior section is relaxed in full extension (tight in flexion) • Posterior section is relaxed in full flexion (tight in extension)
Knee ligaments • Lateral collateral ligament (LCL) – Extra capsular “band like” like” ligament – Provides lateral stability to the knee – Orientation • From lateral epicondyle of femur to head of fibula – Proximal to distal (anterior to posterior)
This blend with the capsule makes it difficult to have a complete complete tear. Also, tissue approximation remains despite very severe tears, therefore healing can occur without surgical repair.
Complete tears need surgical repair due to loss of tissue contact. contact.
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Collateral Ligaments (Kinesiology) • In full knee extension – LCL and posterior portion of MCL are taut – CloseClose-packed position of the knee – Ligamentous stability testing should lead to minimal to no motion
Collateral Ligaments (Kinesiology) • ER of the tibia (knee in flexion) – ER of the tibia creates tension on the collateral ligaments – This has implications for injuries and testing
Collateral ligaments (Kinesiology) • In knee flexion – The collateral ligaments are more relaxed – Some joint play exists when performing the valgusvalgus-varus tests with the knee at 2020-30° 30° of flexion
Collateral Ligaments (Kinesiology) • IR of the tibia (knee in flexion) – IR of the tibia decreases tension on the collateral ligaments
• Test for reproduction of pain
Knee ligaments (Stability Function) • Medial collateral ligament (MCL) – Valgus stress @ 20° 20° of knee flexion* flexion* • • •
MCL = 81% of stress ACL = 14% of stress Capsule = 5% of stress
* Valgus test of the knee at 20° 20° of flexion is more specific for the MCL
Knee ligaments (Stability Function) • Medial collateral ligament (MCL) – Amount of medial opening upon testing ** • 0 mm indicates no injury or very minor injury: first degree sprain • 3 mm indicates partial MCL tear: 1+ laxity, mild second degree sprain • 6 mm indicates partial MCL and capsule tear: 2+ laxity, severe second degree sprain • 10 mm indicates complete MCL, capsule and likely anterior cruciate tear: 3+ laxity, third degree sprain
** Greater than the other knee
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Knee ligaments (Stability Function) • Medial collateral ligament (MCL) – Valgus stress @ 0° 0° of knee flexion* flexion* • • • •
MCL = 57% of stress Posteromedial capsule = 18% of stress ACL and PCL = 14% of stress Anterior and middle capsule = 8% of stress
* Test less specific to the MCL (does not isolate action of MCL as well). Instability indicates a more severe injury of the MCL and and likely involves the capsule and ACL (i.e., you need more than just just the MCL to be injured if instability in full knee extension).
Knee ligaments (Stability Function)
Knee ligaments (Stability Function) • Lateral collateral ligament (LCL) – Varus stress @ 20° 20° of knee flexion* flexion* • • • • •
LCL = 72% of stress ACL and PCL = 12% of stress Iliotibial band and popliteus = 10% of stress Posterior capsule = 5% of stress Anterior and middle capsule = 4%
* Varus test of the knee at 20° 20° of flexion is most specific for the LCL
Knee ligaments (Stability Function)
• Lateral collateral ligament (LCL) – Amount of lateral opening upon testing • 0 mm indicates no injury or very minor injury: first degree sprain • 5 mm indicates partial LCL tear: 1+ laxity, mild second degree sprain • 7.5 mm indicates partial LCL and capsule tear: 2+ laxity, severe second degree sprain • 10 mm indicates complete LCL, capsule and likely cruciate tear: 3+ laxity, third degree sprain
** Greater than the other knee
MCL Tear • Definition – Partial or complete tear of ligament (sprain -- grade 1st, 2nd, or 3rd degree)
• Mechanism of injury – Excessive valgus stress (ex. lateral to medial force applied to lateral aspect of the knee)
• Lateral collateral ligament (LCL) – Varus stress @ 0° 0° of knee flexion* flexion* • • • • •
LCL = 55% of stress ACL and PCL = 22% of stress Posterior capsule = 13% of stress Anterior and middle capsule = 4% of stress Iliotibial band = 5% of stress
* Test less specific to the LCL. If instability noted in full extension, extension, check the ACL and PCL.
MCL Tear
• Signs and symptoms (findings depend on the severity of the injury)
Valgus stress test
– Tenderness to palpation – Swelling – Pain with valgus stress testing – Laxity with valgus stress testing – EndEnd-feel Palpation of ligament (above and below the joint line)
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MCL Tear
MCL Tear
• Signs and symptoms
• Laxity rating
– Tenderness, swelling, pain and laxity with stress testing, soft or empty endend-feel
Laxity End-feel
firm
soft
empty
MCL Tear • First degree
MCL Tear • Second degree
– Not repaired, takes just a few days to heal – Protection (crutches, no resisted hip adduction) adduction) – Rest – Ice – Compression – Elevation – Return to activities based on pain (likely 7 - 10 days)
– Same as first degree – Also • • • •
Motion brace for 2 - 3 weeks PWB with crutches for 2 - 3 weeks Return to full activities 2 - 3 months Fully heal in 4 - 5 months PostPost-surgical brace (also called motion brace)
See complete outline of rehabilitation program in notes
MCL Tear
MCL Tear • Third degree – Typically not repaired • If the ACL also torn, MD will repair both
– Weeks 0 - 4 • • • • •
Cast or braced in full extension for 2 - 3 weeks* weeks* SLR Hip ABD Hip extension Avoid resisted hip adduction
* The brace or cast may be set at 20° 20° of flexion. The ligament heals in a shortened position, but it may be difficult to get full extension extension back.
• Third degree – Weeks 4 - 6 • Motion brace • Progressive ROM • Progressive strengthening
– Week 6 - 12 • Progress strength and function • Return to full activities 2 - 3 months • Fully heal in 4 - 5 months * Note that a severe MCL tear will not heal properly if the ACL is also torn. ACL needs to be repaired (MCL may or may not be repaired at the same time)
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LCL Tear
LCL Tear
• Definition – Partial or complete tear of ligament (sprain -- grade 1st, 2nd, or 3rd degree)
• Mechanism of injury
• Signs and symptoms – The amount of tenderness, swelling, pain and laxity with stress testing depends on the severity of the injury (see next slide)
– Excessive varus stress (ex. medial to lateral force applied to medial aspect of the knee)
Palpate LCL
LCL Tear
Varus stress test
LCL Tear
• Signs and symptoms
• Rating
– Tenderness, swelling, pain and laxiy with stress testing, soft or empty endend-feel
Laxity End-feel
firm
soft
empty
LCL Tear • First degree – Not repaired, heal in a few days – Protection (crutches, no resisted hip abduction) – Rest – Ice – Compression – Elevation – Return to activities based on pain (likely 7 - 10 days)
LCL Tear • Second degree – Same as first degree – Also • • • •
Typically not repaired Motion brace for 2 - 3 weeks PWB with crutches Return to full activities 2 - 3 months
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LCL Tear • Third degree
• Third degree
– Surgical repair – Weeks 0 - 4 • • • • •
LCL Tear
Cast or braced in full extension for 2 - 3 weeks* weeks* SLR Hip ADD Hip extension Avoid resisted hip abduction
– Weeks 4 - 6 • Motion brace • Progressive ROM • Progressive strengthening
– Week 6 - 12 • Progress strength and function
* The brace or cast may be set at 20° 20° of flexion
ACL and PCL
Knee ligaments • Anterior cruciate ligament (ACL) – Anterior tibial spine to medial aspect of lateral femoral condyle – IntraIntra-articular, articular, extraextra-synovial – Length (3.5 cm), width (1.1 cm) – Three bundles • Anteromedial - taut in flexion • Posterolateral - taut in extension • Intermediate - taut throughout the movement
Knee ligaments • Anterior cruciate ligament (ACL) – Primary role • Prevents forward glide of tibia on the femur* femur*
– Secondary role • • • • •
Restraint for varus/valgus force* force* Controls/limits rolling and gliding of tibiofemoral joint Assists screwscrew-home mechanism (promotes ER of tibia) Prevents internal rotation of tibia on femur* femur* Prevents hyperextension* hyperextension*
Knee ligaments • Posterior cruciate ligament (PCL) – Posterior tibial spine to lateral aspect of the medial femoral condyle – Primary role • Prevents posterior glide of tibia on the femur
– Secondary role • Prevents hyperextension • Restraint for varus/valgus force
* Directly relates to mechanism of injury
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Knee (Kinesiology) • In full knee extension – All ligamentous structures are tight – CloseClose-packed position of the knee – Ligamentous laxity testing with varus/valgus forces should lead to minimal to no motion, consequently valgus/varus laxity in this position indicates likely injury to the cruciate ligaments
Knee (Kinesiology) • In knee flexion – Various sections of the ACL are under some tension throughout the movement • This quality is part of the difficulty in reconstruction of the knee (providing a graft that will be under tension throughout the full range of knee motion requires very precise location of the graft)
– Maximum “joint play” play” is at 20° 20° of flexion
Knee (Kinesiology) • With ER of the tibia (knee in flexion) – The cruciate ligaments spread apart (become looser)
Knee (Kinesiology) • With IR of the tibia (knee in flexion) – The cruciate ligaments twist together (become tighter)
This has implications for injuries and testing. NonNon-contact isolated ACL injuries occur with tibia IR with knee extended.
Knee ligaments (Stability Function) • Anterior cruciate ligament (ACL) – Anterior drawer sign with tibia in neutral position @ 90° 90° of knee flexion (Anterior drawer test) • ACL = 85% of stress • MCL, LCL and capsule = 15% of stress
– Anterior drawer sign with tibia in neutral position @ 30° 30° of knee flexion (Lachman (Lachman test)
Knee ligaments (Stability Function) • Posterior cruciate ligament (PCL) – Posterior drawer sign with tibia in neutral position @ 90° 90° of knee flexion (posterior drawer test) • PCL = 89% of stress • Posterolateral capsular complex = 11%
• ACL = 87% of stress • MCL, LCL and capsule = 13% of stress * Both tests are very specific to the ACL. Most look at the Lachman test as being more specific.
* The test is very specific to the PCL.
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Loads Applied to ACL and PCL During Exs • Passive range of motion of the knee – No shear between 0 - 60° 60° of flexion – Flexion > 60° 60° loads the PCL – Flexion > 120° 120° loads the PCL and ACL – Hyperextension loads both the ACL and PCL
Loads Applied to ACL and PCL During Exs • Isometric knee extension – Same load pattern as with active knee extension – The ACL is loaded from 0 - 60° 60° of flexion (peak load at 20° 20° of flexion) – The PCL is loaded from 60° 60° to 120° 120° of flexion
Loads Applied to Cruciate Ligaments • Squat
Loads Applied to ACL and PCL During Exs • Active and resisted knee extension – The ACL is loaded from 0 - 60° 60° of flexion (peak load at 20° 20° of flexion) – The PCL is loaded from 60° 60° to 120° 120° of flexion
Loads Applied to ACL and PCL During Exs • Active and resisted knee flexion – The PCL is loaded throughout – The more knee flexion the greater the load
Loads Applied to Cruciate Ligaments • Summary
– PCL load throughout the motion * – Greater load with deeper angles
• Leg press – PCL load throughout the motion
* More recent studies show an anterior shear in the early part of the squat
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Loads Applied to Cruciate Ligaments • Summary
EMG Activity With Knee Exercises • Exercises with dominant quadriceps activity – Active and resisted knee extension – Leg press – Step ups – Wall squats
EMG Activity With Knee Exercises • Exercises with dominant hamstrings activity – Active and resisted knee flexion – Ascent phase of the squat (with trunk leaning forward) – Retro stepping (stair master) – Plyo lunges (plyo (plyo walking)
EMG Activity With Knee Exercises • Exercises with high coactivation – Fitter – Slideboard – Squat 0 - 45° 45°
EMG Activity With Knee Exercises • EMG ratio with various exercises
ACL Tear • Definition – Complete tear of ligament – Can’ Can’t be repaired, needs to be “replaced” replaced” by “reconstruction” reconstruction”
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ACL Tear
ACL Tear
• Mechanism of injury
• Signs and symptoms (acute tear)
– Most often does not involve contact – Sudden deceleration (forceful quad contraction) – IR of tibia with knee extended • Cutting right while standing on right knee
– Hyperextension • ACL goes first, then PCL, then popliteal artery could be injured with hyperextension greater than 35° 35°
– Hemarthrosis (very rapid and large amount of swelling) – “pop” pop” at the time of the injury – Unable to bear weight – Feeling of knee instability Lachman test – Laxity with testing • anterior drawer test, Lachman test, knee arthrometer
– Positive MRI
– Hyperflexion
KTKT-2000 arthrometer
ACL Tear
ACL Tear • Signs and symptoms (chronic stage) – History of the acute condition – Functional instability (episodes of giving way) – Laxity with testing – Positive MRI – Arthritic changes
ACL Tear • Conservative treatment – Goals
• Treatment options – Conservative option is possible • If patient is no more than moderately active • If patient has strong knee musculature • If patient has good secondary restraints (capsule, MCL, LCL)
ACL Tear See rehabilitation program in the notes
• Decrease swelling • Progressively improve range of motion • Progressively improve strength following the principles of ACL repair to reduce anterior translation of tibia during rehabilitation exercises • Monitor giving way episodes (should have none) • Progressive functional activity • Balance/proprioception Balance/proprioception training ++++ • Using a functional knee brace may also help Conservative management requires the secondary restraints (capsule) and the musculature to provide stability
• Treatment options – Surgical option is preferred • If patient remains very active (decision made at time of injury) • If knee remains swollen and painful (decision made a moderate amount of time after the injury) • If patient has functional instability (decision made a moderate/extended amount of time after the injury) • If patient has arthritic changes (long term decision)
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ACL Tear • Surgical treatment – Timing • Typically at least 3 weeks after injury (once swelling and inflammation is resolved and ROM is normal) • Early reconstruction increases the risk of arthrofibrosis • So, in fact, patients go through the conservative management first (for the first few weeks)
– Graft options (strength of graft compared to original ACL) • • • •
Patellar tendon (most popular option) (160% (160%)) Semitendinosus (75%) 75%) Gracilis (49%) 49%) Iliotibial band (38% (38%))
PTG: patellar tendon graft (bone(bone-tendontendon-bone graft)
ACL Tear • Healing process graph
ACL Tear • Healing process of the graft – The graft consists of the midmid-third of the patellar tendon (about 10 mm in width) with small bone “plugs” plugs” at both ends – Revascularization of the tendon takes place over an 8 to 12 week period (the tendon getting initially weaker in the first 2 weeks than progressively stronger). The graft is weakest between 2 to 8 weeks after surgery – Continues to heal for at least 9 months – EndsEnds-up at 80% of the initial strength of the tendon • (80% of 160%, because the initial graft was stronger than the original ACL, the end result is a graft about 130% the strength of the original ACL)
ACL Tear • Rehabilitation highlights (ACL -PTG) – PWB (crutches) for 2 weeks – Knee brace for 6 weeks • Locked in full extension for 3 weeks when ambulating • Sleep with brace on for 2 weeks
– 0-90 degree ROM by 7 days – full ROM by 44-6 weeks – NO NWB active and resisted knee extension from 00-45 degrees – Start WB exercises (mini(mini-squats) 22-3 days postpost-surgery – Start NWB active knee extension 9090-45 degrees 22-3 days post surgery – Gradual return to activities at 3 months – Full return to activities at about 6 months
ACL Tear • Rehabilitation highlights (ACL(ACL-hamstrings)
ACL Tear • Rehabilitation program
– Very similar rehabilitation – ** Slower for the first 3 months – ** Address “hamstring injury” injury” with progressive rehabilitation of the hamstrings
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ACL Tear • Selection of exercises – Exercises with high degree of coactivation • Fitter, slideboard, slideboard, squat 0 - 45° 45°
– Exercises that isolate hamstrings
ACL Tear • Outcome – 92% success rate – 77% return to prepre-injury level – Significant risk factors for poor recovery are
• Active and resisted knee flexion • Ascent squat, retro stepping, plyo lunges
• Lack of formal rehabilitation for greater than 4 months • MCL or LCL repair performed with ACL repair
– Avoid exercises that increase anterior shear of tibia • Active and resisted knee extension 45 to 0° 0°
– Although quadriceps dominant, the following exercises create a posterior shear of the tibia and are safe to do • Leg press, step ups, minimini-squat
Clinical tip: Sometimes, patient may feel a “click” click” during knee movement at 3 month post surgery. This is due to thickening of the graft with revascularization. Should go away on its own.
ACL Tear • Complications postpost-ACL surgery – Joint stiffness - arthrofibrosis (most common) – Osteoarthritic changes – Decreased muscle strength – Decreased function
ACL Tear • Concomitant surgery – If simultaneous meniscus repair • Avoid flexion greater than 90° 90° for 4 weeks • No isolated hamstrings action for 9 weeks
– If simultaneous MCL repair • Regain full extension quickly to prevent excessive MCL tightness (follow physician’ physician’s guidelines for MCL in regard to range of motion)
– If simultaneous PCL repair • Treat as a PCL reconstruction for first 12 weeks
ACL Tear • Incomplete tears (diagnosed by MRI) – If about 25% torn • 12% will eventually rupture
– If about 50% torn • 50% will eventually rupture
– If about 60 - 70% torn • 85% will eventually rupture • 100% if continue with sports
• Definition
PCL Tear
– Complete tear of ligament – 2 - 3% of very high level athletes have a PCL tear without knowing it
• Mechanism of injury – – – – –
Posteriorly directed force on the tibia with knee flexed Hitting the dashboard (50% of cases) Fall on proximal tibia Hyperextension (ACL and PCL) Forced hyperflexion
Treat as a grade 1 or 2 injury, except follow guidelines of rehabilitation for ACL reconstruction
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PCL Tear
PCL Tear
• Signs and symptoms (acute tear) – – – – – –
Godfrey test
Mechanism of injury MinimalMinimal-toto-mild effusion Positive tests for laxity Difficulty weight bearing Feeling of instability MRI
Sag test Look and palpate alignment
PCL Tear • Treatment options – Conservative most of the time – Especially if: • Laxity limited to the PCL • Laxity of 15 mm or less • Posterior drawer decreased by internal rotation of the tibia on the femur (indicating good secondary restraints)
• Signs and symptoms (chronic) – Functional instability (episodes of giving away) – Positive tests for laxity – Positive MRI – Arthritic changes
Posterior drawer test
False positive anterior drawer test
Quadriceps extension test
PCL Tear • Treatment outline (conservative) – Control swelling – Early range of motion – PRE for quadriceps – Avoid deep squats – Avoid isolated hamstring strengthening – Return to sports (6 weeks)
See rehabilitation program in the notes
PCL Tear • Prognosis of conservative option – 30 to 85% return to prior activity level – 50% have knee pain (tibiofemoral (tibiofemoral and/or PFJ joints) – 80% develop osteoarthritic changes within 5 - 6 years (patellofemoral (patellofemoral joint and medial femoral condyle) condyle) – Key to success is quadriceps strength
PCL Tear • Indications for surgical option – Laxity greater than 15 mm – Posterior drawer not decreased by IR of tibia – Other ligamentous laxity – Symptomatic (knee instability) despite rehabilitation – PostPost-traumatic arthritis
With PCL deficient knee: PFJ compression forces increase by 16%. So, monitor the PFJ joint during rehabilitation.
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PCL Tear
See rehabilitation program in the notes
• Guidelines post surgery
Tibiofemoral Joint Forces • Posterior shear
– PWB (crutches) for 4 weeks – Brace for 12 weeks • Locked in full extension during ambulation for 7 weeks (unlocked 5 weeks)
– – – – – – – –
Sleep with brace on for 2 weeks 0-60° 60° of ROM by 7 days, 00-90° 90° week 2, full ROM week 7 Avoid active and resisted NWB knee extension from 90 -45° 45° Active NWB knee extension from 4545-0° starts 22-3 days post surgery Start WB exercises (mini(mini-squats 00-30° 30°) at 4 weeks Hamstring curls started at 12 weeks Gradual return to activities at 3 -4 months – full return at 6 months Avoid kneeling
Only 50 - 65% of PCL surgeries have favorable results (meaning the patient is better after surgery)
Knee Effusion
Grafts for ACL and PCL Reconstruction • Synovitis • Autogenous graft – Graft from same person
• Allograft – Cadaver graft (another person)
• Synthetic material graft – GoreGore-tex
– Slow and progressive (hours) – Small to large amount of swelling – Cool to warm
• Hemarthrosis – Rapid swelling (minutes) – Large amount of swelling – Hot Three reasons for hemarthrosis of the knee: dislocated patella, intraarticular fracture and ACL rupture
Buckling or Giving Way of the Knee • Indicates an internal derangement of the knee – Meniscus tear – ACL or PCL deficient knee
• Caused by reflex inhibition of the quadriceps, due to “abnormal mechanics” mechanics”, resulting in buckling of the knee
Superior TibioTibio-fibular Joint • Arthrodial joint • Fibula moves proximal and anterior with knee extension – Due to attachment (tension) of the LCL
• Fibula moves distal and posterior with knee flexion – Due to traction from biceps femoris Assess mobility after immobilization in cast or brace, especially especially if pain develops in that region. Motion easy to return with joint joint mobilization techniques.
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