Knee ligamentous issues Flashcards
Which are considered stronger, the cruciate ligaments or the collateral ligaments?
- cruciate
Are the cruciate ligaments intra/extra capsular and/or synivoal?
- they are intracapsular and extra-synovial
What structures is the MCL connected to?
- medial meniscus and the joint capsule
T or F;
The MCL has a poor blood supply, healing slowly.
- F
Has a rich blood supply, healing relatively well
The LCL connects to which structure?
- joins with the biceps femoris muscle to form a conjoined tendon, attaching into the proximal fibular head
Which ligament is the most commonly injured?
- ACL
The ACL becomes taut during ____ and is responsible for the which accessory motion?
- taut during flexion
- responsible for the glide after the knee rolls
The anteromedial bundle (AMB) of the ACL prevents _______ translation in ______, and the posteromedial bundle of the ACL prevents _______ translation in ________
o Anteromedial band (AMB) prevents anterior translation in flexion
o Posteromedial band (PMB) prevents posterior translation in extension
Which ligament resists hyperextension of the knee?
- ACL
The ACL acts as a secondary restraint against which motions?
- varus and valgus
ACL is more likely a ______ injury, compared to teh PCL which is more likely a _______ injury
- ACL more likely non-contact
- PCL more likely contact
The PCL becomes taut during ______ and is responsible for which accessory motion?
- becomes taut in extension; as femoral condyles roll forward, becomes taut and then causes a glide
MCL primarily restricts which motion(s)?
- valgus and lateral rotation
The MCL is most taut in which position?
- full extension
In full extension, the MCL accounts for ___% of the restraining force against valgus. At 25* of flexion, the MCL accounts for ____% of the restraining force agianst valgus.
- 57%
- 78%
What is a weird paradox about the MCL?
- the MCL is most taut in full extension, however is more responsible for stabilizing valgus load in slight flexion. May be taking on greater loading when slightly lax.
LCL primarily restricts which motion(s)?
- varus
- also limits external and internal rotation
The greatest strain on the LCL occurs in which position and with which force?
- full extension with tibial external rotation
What ligament helps limit anterior and internal rotation forces in an ACL deficient knee?
- LCL
Which ligament is the least often injured?
- LCL
T or F:
The knee is the most commonly injured joint
- T
Which ligaments are most often injured?
- ACL has highest rate, followed by MCL
Ligamentous injury is more likely in what demographic?
- younger female athletes (14-18 yo)
- more often in athletics in general
Some studies have shown as high as a ___:___ ratio for ______ (gender) for ligamentous knee injury
10:1, female to male ratio
ACL injuries typically occur in what situations?
- knee in slight flexion with tibial rotation in a WB position
- pivoting, landing, changing direction
What is the unhappy triad?
- ACL, MCL, medial meniscal injury
A dashboard injury describes what ligamentous injury?
- PCL
Hemarthrosis and immediate joint effusion are hallmark signs of what knee injury?
- more common with ACL and PCL injury
Describe execution of the DIAL test and interpretation.
- Prone w/ knees at 90* flx
- Both feet up, ER both tibias at 90* and 30*
- Looking for significant asymmetries in laxity
- If symmetrical in 90* but asymmetrical in 30*, likely that the PCL is intact, but the posterolateral corner may be deficient
What tests are appropriate to assess anterior/posterior stability?
- Lachman’s (reverse Lachman’s)
- Anterior drawer (posterior drawer)
- Pivot shift (reverse pivot shift)
What type of imaging is most sensitive to rule out ligamentous involvement?
- MRI
- radiographs should be first
T or F;
It is possible for a professional level athlete to return to competitive level performance without surgical management for an ACL tear.
- T
- requires a significant focus on motor control/strength
What are the two primary focuses for ACL and PCL rehab?
- motor control
- strength of the LE
What muscles provide anterior tibial shear?
o Quads through patellar tendon o Gastroc (proximal tendon wraps posterior tibia)
What muscles provide posterior tibial shear?
o Hamstrings (increases as knee flexion increases) o Soleus (when in closed chain)
What is a consideration for open-chain therex after ACL injury?
- open-chain quad exercise is thought to put more anterior shear force on the tibia, especially in full extension
What are 4 examples of things that may put significant strain on an ACL?
- isometric quad contraction at 15* flx
- squatting
- Lachmans
- active flx/ext w/ weighted boot
What are 2 examples of exercises that may minimize ACL strain?
- isometric quad contraction at 30 to 90* flx
- simultaneous quad/hamstring contraction at 60-90*
What muscle shares the role of the PCL?
- popliteus
What muscle will reduce strain on the PCL between which range? (not the popliteus)
- quads, between 20-60*
When does the gastroc place the greatest strain on the PCL?
- when the knee is flexed over 40*
What are the 2 principles for MCL injury management?
- manage pain and inflammation initially (RICE)
- progressively increase controlled stress, with less stress in full extension
What ROM should you be more conservative with when adding stress during MCL rehab?
- less stress in full extension
How long can remodeling take with an MCL injury?
- some studies show up to a year
What are the 2 principles for LCL injury management?
- manage pain and inflammation initially (RICE)
- progressively increase controlled stress, with less stress in full extension
- same as MCL
What is the expected outcome for LCL/MCL injury with rehab?
- usually responds well to conservative care
What are the flexor muscles of the knee? (8)
o Semimembranosus o Semitendinosus o Biceps femoris (long and short heads) o Gracilis o Sartorius o Popliteus o Soleus o Gastroc
What are the extensor muscles of the knee? (4)
o Quadratus femoris
o Vastus lateralis
o Vastus intermedius
o Vastus medialis
What two muscles attach to the patella via the patellar retinaculum?
- vastus lateralis
- vastus medialis
What muscles limit anterior translation of the knee?
o TFL via the ITB
o Soleus (only in WB)
o Glute max (only in WB)
What muscles limit posterior translation of the knee?
o Quadriceps
o Popliteus
o Medial and lateral heads of the gastroc
What muscles limit valgus stress at the knee?
o Pes anserinus
o Semimembranosus
o Medial head of gastroc
What muscles limit varus stress at the knee?
o Biceps femoris
o Lateral head of gastrocnemius
Define quadriceps insufficiency.
o Failure of voluntary activation of skeletal muscle is defined as the inability to produce all available force of a muscle despite maximal voluntary effort
The quads are __x as strong as the hamstrings
- 2x
What ROM is the most difficult to create force with for the quads?
o Last 15* of extension are most difficult to create active force in open chain, due to lack of pulley through patella; quad contraction must increase in order to compensate for the decrease in the moment-arm
What are some potential causes for quad lag? (3)
Patellar tendon graft
Prolonged immobilization of the knee
Active insufficiency (contracture)
What other muscles assist the quad with stability in WB knee extension?
- glute max
- soleus
Asymmetrical differences in quad strength 6 months after TKA range from ~____ to ____%.
15-21%
T or F;
Quad weakness is directly related to the development of knee OA
- T
T or F;
Quad weakness has not been found to have an association with decline in physical function
- F
T or F;
Decreased function and motor control of the quads results in a decrease in compressive forces inside the tibiofemoral joint.
- F; increased compressive forces
Decreased control/strength of the quads can result in damaging what other structures at the knee?
- articular surfaces (development of OA; increased compressive force)
- menisci (increased shear)
- ligaments
- patella (general maltracking, as well as increased compression of the PF joint when in deeper knee flexion; tension on the quad in deep flexion pulls the patella a bit away from the femur)
In general, less strength = increased reliance on passive structures for stability
In weight bearing, the femur rotates _______ to extend (lock), and ________ to flex (unlock)
- medially to extend
- laterally to flex
Posterior shear throughout leg press/squat peaks between ___* and ___* of flexion
- 83* and 105*
Quad function in WB is reinforced by which muscles?
- glute max
- soleus
T or F;
There is no anterior shear at the knee in WB
T
In weight bearing, the tibia rotates _______ to extend (lock), and ________ to flex (unlock)
- laterally to extend
- medially to flex
In open-chain, the greatest forces for the quad contraction occur when? In closed-chain?
- last 15* of extension in open chain
- with increased flexion in closed chain
Anterior shear is found between ___ and ___ during open-chain leg extension exercise, peaking between ____ and ____
10-40* of extension
- peaks between 10-20*
Posterior shear is found between ___ and ___ of knee flexion
60-100*
What hip musculature is important to focus on to improve knee stability?
- hip abductors
- hip extensors
What 3 functional muscles assessments were noted in the presentation for muscle impairment for knee issues?
- hop tests (single leg and triple hop)
- FMS tests for the lower extremity
- Lower quarter Y-balance
What % of ACL injuries are managed surgically?
- 90%
What % of surgically managed ACL injuries also had a meniscal procedure at the same time?
- 90%…weird
What biases are there to ACL reconstruction demographics?
- Men are more likely to have ACL reconstruction
- White people are more likely to have reconstruction
- Increasingly they are outpatient procedures conducted with a nerve block, not general anesthesia
T or F;
It has not been demonstrated that operative management of ACL injury is superior to non-operative management
- T
What are a few limitations with the research for operative vs non-operative management of ACL injury?
- it’s pretty early in the literature process at this point
- there is significant crossover from the non-surgical to the surgical groups in many of the studies
What are some basic concepts for why to operatively manage an ACL injury? (4)
Restore knee stability
Prevent meniscal damage
Protect articular cartilage
Avoid degenerative changes
T or F;
Some portion of the ACL is taut throughout the entire range.
- T
What are some issues created by operative management of an ACL injury? (5)
Pain Effusion ROM limitation Decreased muscle function Impaired kinesthetic awareness
T or F;
Most people return to their previous level of activity following ACL injury.
- T
T or F;
Most people return to their previous level of health-related quality of life after ACL injury.
- F
- about a 10% reduction; so they get better, but they typically don’t make it all the way back.
The anterior drawer test might preferentially test which portion of the ACL?
- anteromedial bundle prevents anterior translation in flexion
- posteromedial bundle prevents posterior translation in extension
What percentage of ACL injuries are non-contact?
- ~60%
What is the common knee position in a non-contact ACL injury?
- knee in, toe out
- valgus with IR
Non-contact ACL injury has the greatest risk of occurring during _______?
- competition
What is the “most clinically” accurate test for ACL laxity?
- Lachman test
What are the 3 primary tests for ACL laxity?
- Lachman test
- Pivot shift
- Anterior drawer
When is the pivot shift more appropriate for use?
- under anesthesia; won’t work if pt is guarding
- used to determine integrity of repair
What is a third test for ACL injury? Is it more sensitive or specific?
- Loss of extension test
- more specific than sensitive
What is the gold standard for ACL tear detection?
- MRI
What is a Segond fx? What is it indicative of?
- avulsion fx of the lateral tibial plateau
- traditionally though of as occurring in conjunction w/ ACL tear. May actually just be an avulsion of the anterior longitudinal ligament instead
What are the kinematic differences between ACL copers vs non-copers?
- copers: stable joints with fewer episodes of giving way, and fairly normal ROM and forces during functional activities/gait
- non-copers: increased joint laxity, reduced knee ROM during hop tests, reduced knee compression and shear forces during gait
What are the EMG characteristics of an ACL coper?
Poor quad control
Preferentially utilized a vastus lateralis and medial HS activation pattern during a cutting drill
What are the EMG characteristics of an ACL non-coper?
Poor quad control
Increased quad activity during knee flexion activities
Increased co-contraction strategies (stiffening strategy)
What are the functional differences between ACL copers and non-copers?
- copers generally demonstrate increased functional scores and hop tests
- non-copers are reluctant to participate and demonstrate fear avoidant behaviors
What differences exist between ACL copers and non-copers with activity?
- not really much. ~82% return to activity in both groups; fairly similar between groups for activity and self-report
The U of Delaware found what 4 criteria to ID potential ACL copers?
No episodes of giving way
Over 80% 6m timed hop test
Over 80% KOS ADL subscale
Over 60% Global Rating of Knee Function
About what percentage of people can be identified as true ACL copers?
- ~40% on initial screen
- however, 70% of non-copers were actually copers at one year follow up after being ID’d as non-copers
When is the typical timeframe to assess ACL coper vs non-coper?
- ~10 sessions of treatment
- at least 60 days, but before 6 months, usually. Really they just need to be at a place where hop testing is appropriate.
T or F;
It doesn’t make a difference if you do OKC vs CKC or both for ACL rehab.
- F
- current evidence indicates to do both. OKC may significantly improve quad function
T or F;
ACL rehab should include perturbation training
- T
With an ACL coper rehab program, when should they expect to resume prior level of activities?
- within 6 months to one year….I would argue closer to a year.
What type of performance would you want to see with an ACL repair pt prior to being ok with them on a leg extension or curl machine?
- tolerating cuff weights of 12-15 reps with 10#
What are general ROM considerations for early ACL rehab for open chain therex?
- limit knee extension from 90-60* initially when working knee extensor strengthening
- limit knee flexion (HS curls) from 0-90* to avoid active insufficiency or hamstring cramping. Also don’t do it if it was a HS graft.
What is an appropriate timeframe to expect independent ambulation with minimal deviations following ACL repair?
- 2-4 weeks
What is an appropriate timeframe to expect 110* flexion after ACL repair?
- 2-4 weeks
What is an appropriate timeframe to expect 125* flexion after ACL repair
- 6-8 weeks
What is the timeframe goal to achieve 60% quad strength after ACL repair?
- 4 weeks
What is the timeframe goal to achieve 80% quad strength after ACL repair?
- 8-10 weeks
When can a pt with an ACL repair expect to start running on a treadmill? What criteria should they hit first?
- ~8 weeks
- normal gait while walking
- at least 70% quad strength
- minimal pain and effusion
What are the criteria to start agility training following ACL repair?
Track or road running for 1-2 miles without pain, swelling, instability
80% quad strength at least
Start at no >50% speed, then progress to 75%, then 100%
No pain, swelling, instability
T or F;
There is increased risk of meniscal damage if the ACL is not repaired.
- T-ish
- one study has shown increased rates of meniscal tear without repair vs with repair
T or F;
Rates of knee OA are higher in pts that have surgical ACL repair vs those with non-operative management.
- F
Define posterolateral instability
Posterior rotational subluxation of the lateral tibial plateau in relation to the femoral condyle, with the tibia rotating externally in relation to the knee axis
What is the posterolateral ligamentous complex also known as?
- arcuate ligamentous complex
What does the posterolateral ligamentous complex consist of? (9)
LCL
Arcuate ligament
Popliteofibular ligament
Posterior third of the lateral capsule
Fabellofibular ligament
Tendoaponeurotic unit formed by the popliteus muscle (not always included)
Biceps femoris tendon (not always included)
Popliteal meniscal ligament (not always included)
Lateral gastroc (not always included)
Why should you test for MCL integrity (valgus stress) at 30* of knee flexion?
- it places the ACL and PCL on slack
What are the signs and symptoms of a collateral ligament injury? (6)
- MOI: varus or valgus trauma
- varus or valgus stress testing will be positive
- swelling/ecchymosis
- TTP of the ligament
- difficulty with pivoting/cutting
- joint effusion may be present if there is meniscal involvement
Is palpation of the LCL or MCL likely more sensitive when screening for a collateral ligament injury? Why?
- LCL palpation is likely more sensitive, as the LCL isn’t connected to the joint capsule or meniscus
Describe execution of the varus stress test
- pt in supine
- knee in extension and flexed 20-30*
- introduce varus stress at the joint line
- positive test is laxity and/or pain
What are the signs and symptoms of a PCL injury? (6)
o Posterior knee pain
o Less effusion than ACL injury
o Flexion beyond 90* may increase pain (open-chain)
o Difficulty descending stairs, squatting, running
o Not as much of a problem with quad inhibition
o + sag sign, + posterior drawer, reduced palpation of tibial plateau step off
What are the potential mechanisms of injury for a PCL injury? (4)
o Hyperflexion
- Fall on a flexed knee with foot in plantarflexion
o Hyperextension mechanisms; step in a pot hole
o Blow to anterior tibia
What are some general symptom/sign differences between ACL and PCL injury?
- ACL injury will likely have greater joint effusion, as well as greater quad inhibition than PCL injury
Describe execution of the posterior drawer test
Patient is supine with knee flexed to 90*
Assess tibial plateau
• Tibial plateau should rest ~1cm anterior to femoral condyle
• Easy to create a situation where a fals negative is obtained
Thumbs on joint line, apply a posterior force
Positive test is excessive posterior translation and/or a soft end feel
What is the general standard test for PCL injury?
- posterior drawer
What should the starting position for the posterior drawer test be for the tibia?
- tibial plateau should rest ~1 cm anterior to the femoral condyles; easy to create a false negative
Posterolateral instability most often occurs in conjunction with injury to what other knee structures?
- ACL or PCL
- Less common with something like an LCL
Posterolateral corner injury is most often associated with damage to the ______ nerve
- peroneal
What is a common mechanism of injury for a posterolateral corner injury that occurs with contact?
- usually a direct blow to the anteromedial aspect of the lower leg
What grades of posterolateral corner injuries often have good results with conservative management?
- Grades I and II; higher typically require surgical management
