Leg press and squat create greatest shear force in which direction and affecting which cruciate?
Posterior shear force; PCL
What is most common MOI of PCL injury and what bundle is affected?
Hyperflexion; anterolateral bundle
Initial Test suggested for LCL injury? What is the most specific test?
Initial: Varus in ext Most specific = varus stress at 30
ACL posterolateral bundle taut in? Which test?
taut in extension; Lachman's
"L"achman's = postero"L"ateral
whereas "antero"medial = anterior drawer
Function of posterior oblique ligament
reinforces posteromedial knee joint capsule obliquely on a med to lat diagonal
3 Tests for Posterolateral Corner Injury
Prone ER test (Dial Test): inc at 30 deg, but not at 90
reverse pivot shift test
ER recurvatum test:support knee in slight flex, extend knee and allow it to hypertext. if genu recurvatum and tibial ER is noted compared to other side = + test --Sn Sp not yet determined
How much excursion occurs when ACL is torn?
What portion of the capsular lig hold the menisci to the tibia?
meniscotibial portion ** capsular lig of the knee aka coronary ligament has 2 parts--meniscotibial and meniscofemoral
Describe assessing posterolateral corner during PCL assessment of posterior drawer?
Posterior drawer with tibia in ER shows an increase in laxity compared to neutral posterior drawer--check posterolateral corner
What is a diskoid meniscus?
congenital deformity of meniscus (lateral usu than medial)
Initial Test suggested for MCL injury? What is the most specific test?
Initial: Valgus stress @ full ext > 5 mm--check PCL & ACL--it initially checks all the ligaments (large gapping = more ligamentous testing required) Most specific = Valgus stress at 30 flex > 5 mm
Rel b/w rearfoot position and pfps?
Rearfoot varus in patients with PFPS compared to controls
Initial Test suggested for Posterolateral corner injury? What is the most specific test?
Initial: Dial test increased at 30 and normal at 90 Specific: posterolateral drawer **Prone ER test increases at 30 but not 90
What nerve innervates the ACL & PCL
You notice a patient has anteromedial rotary instability - what 3 ligaments would you expect to be torn?
Posterior oblique ligament ACL MCL
What constitutes the posterolateral corner
arcuate ligament, LCL, popliteal tendon, and lateral head of the gastroc
How do you test for anterior lateral/medial instability
Perform anterior drawer, but **ER of tibia tests anteromedial **IR of tibia tests anterolateral
What is straight medial knee lig instability?
valgus blow in extension--affects PCL, MCL, and middle 1/3 of capsular lig
You have a patient with Insall Salvati measurement of 1.4. What does this indicate. What is the equation for the I-S measurement?
patella alta >1.2 = alta less than 0.8 = baja
Function of Oblique popliteal ligament
reinforces posteromedial knee capsule on a lateral to medial diagonal (think popliteal and popliteus muscle/tendon to remember where it comes from)
Patellar baja may result from adhesions due to which bursa?
infrapatellar bursa (ortho secrets)
What is the MOI for anterolateral rotary instability? Structures affects?
deceleration injury on a planted foot (knee flex with tibial IR with varus applied ) Structures affected: LCL ACL, ITB Pivot Shift is positive
MOI for patellar dislocation?
ER of tibia with valgus stress
Greatest posterior translation occurs in what ROM when PCL is gone?
70-90; PCL is most taut in flex
Initial Test suggested for meniscus injury?
Role of the deep MCL fibers
restrain anterior tibial translation
3 Tests for PCL injury? Overall Sn/Sp?
Posterior Sag Test; quad activating test; posterior drawer good and specific/sensitivity for PCl injuries
What is the difference with eccentric strengthening comparing B vs unilateral strengthening for the knee?
There is no significant difference between unilateral and bilateral eccentric training
patella's position in the trochlear groove base on the center of the sulcus angle
What is Steinmann point tenderness test?
Palpate medial or lateral joint line then flex or ext knee a little. Re-palpate joint line. If tenderness moves posteriorly as knee is flexed, menisicus OR if tenderness moves anteriorly as knee is extended, meniscus AND NOT capsular ligamentous cause
Initial Test suggested for PCL injury? What is the most specific test?
Initial Test: Posterior drawer Specific Test: Post sag, quad activation
5 Most Specific Tests/Subjective Cues from patient for meniscal injury
1. Hx of clicking/locking 2. Pain with max passive knee flexion 3. Joint Line Tenderness 4. Pain with hyperext 5. Pain audible click with McMurrays
Is McMurray's more specific or sensitive?
Specific, not sensitive
Action of the popliteus
OKC: IR of tibia to allow knee flex CKC: ER of femur to allow knee flex
What is in the arcuate complex? function of the arcuate complex?
Arcuate lig, LCL, popliteal tendon Heel strike with knee extended puts strain on posterolateral aspect CKC: controls IR of the femur on stable tibia OKC: controls ER of tibia on stable tibia
Medial rotation of tibia stresses which part of ACL
What is the most commonly used graft for PCL?
Which bursa causes housemaid's knee?
PFPS instability patient--which ROM would you avoid strengthening in?
0-30 of flex
What is anteromedial rotary instability? What structures are disrupted?
MOI: football clip (knee slightly flexed with valgus stress and tibial ER) Structures disrupted: ACL, MCL posterior oblique lig, middle 1/3 of capsular lig,
What signifies a + prone ER test?
> 10 deg difference with ER of the tibia If only PostLat Corner, 30 = inc ER; 90 = no inc If Postlat corner + PLC: 30 & 90 = inc ER of tibia
What indicates problems with the patellar groove based on sulcus angle?
> 140 - patellofemoral problems (Ortho Secrets)
Initial Test suggested for ACL injury? What is the most specific test?
Initial: Anterior Drawer > 6 mm Specific: Lachman's **Pivot shift > 3 mm side to side = + on arthrometer
ACL anteromedial bundle taut? Which test?
throughout flexion; Anterior drawer
**think "antero"medial = anterior drawer
What is segond's fracture?
avulsion fx of the anterolateral margin of the lateral tibial plateau from an ACL injury
What is the main and 2 other supporting rols of the posterior oblique ligament?
Main: control anterior medial rotary instability and prevent valgus as the knee moves into ext Avoids excessive tibial ER and femoral IR
MOI for posterolateral rotary instability?
varus blow from anterior direction on a flexed knee with the foot planted
With the valgus stress test of the knee, what might signify other ligaments are damaged?
5 mm--check PCL & ACL **Valgus stress @ 30 resulting in 10 mm = ACL tear too
What is the patellar tilt test
Knee flex to 20 flex lift lateral aspect of patella upward; + test: unable to lift compared to other side--tight lateral retinaculum
Where is an occult osteochondral defect found in ACL injury?
Lateral femoral condyle or posterolateral tibial plateau
When (how much quad strength) is NMES discontinued with a patient ?
> or equal to 80% force output compared to other side