MCL/LCL/PLC Injuries of the Knee

Question 1

What is the most anterior structure that inserts on the fibular head?

Answer 1

LCL

from anterior to posterior: LCL, poplitealfibular lig, biceps femoris

Question 2

What is the relationship of the LCL to the popliteus origin?

Answer 2

LCL insertion is proximal, posterior and superficial to popliteus

Question 3

What exam findings are found with isolated LCL injuries? LCL and ACL/PCL? LCL and PLC?

Answer 3

Isolated LCL: varus instability at 30° only
LCL and ACL/PCL: varus instability at 0° and 30°
LCL and PLC: dial test instability at 30°

Dial test instability at 30° and 90° is PCL and PLC injury

Question 4

LCL repair or reconstruction uses what interval?

Answer 4

Btw ITB (superior gluteal n.) and biceps femoris (sciatic n.)

Question 5

MCL rupture usually occurs at which location?

Answer 5

Femoral insertion

Question 6

Which injury generally occurs with a MCL tear?

Answer 6

ACL tears (up to 95%)

Question 7

Chronic MCL injuries can have which presentation?

Answer 7

Calcification at the MFC (Pellegrini-Steida lesion)

Question 8

Valgus laxity at 30° indicates injury to what structure(s)?

Answer 8

MCL (isolates superficial MCL)

valgus laxity at 0° indicates posteromedial capsule injury or cruciate injury

Question 9

Prophylactic hinged knee bracing for contact athletes has shown a trend towards decreased rates for which types of injuries?

Answer 9

MCL tears

Question 10

What are indications for operative management of MCL ruptures?

Answer 10

1) in the setting of multi-ligament knee injury
2) displaced distal avulsions with “stener-type” lesion
3) entrapment of the torn end in the medial compartment
4) Continued instability despite non-op mgmt

Otherwise treat with NSAIDs, rest, ice, PT

Question 11

What structures make up the posterolateral corner?

Answer 11

Static: LCL, popliteus tendon, popliteofibular lig, lateral capsule, arcuate lig
Dynamic: biceps femoris, popliteus muscle, IT band, lateral head gastroc

Question 12

What is the most anterior structure that inserts on the fibular head?

Answer 12

LCL

Question 13

What is the dial test for?

Answer 13

PLC injuries
> 10 degrees increased laxity with external rotation at 30 degree knee flexion is isolated PLC
> > 10 degrees increased laxity with external rotation at 30 and 90 degrees knee flexion is combined PLC and PCL

Question 14

Which exercises should be avoided in the rehab of PLC injuries?

Answer 14

Active hamstring exercises

Question 15

What is the incidence of peroneal nerve injury in PLC repair/reconstruction?

Answer 15

15-30%

Question 16

What must be addressed prior to any PLC reconstruction or repair?

Answer 16

Mechanical varus malalignment; higher rate of failure with varus deformity; address with HTO

Question 17

A positive reverse pivot shift test and negative posterior drawer is indicative of injury to what structure(s)?

Answer 17

PLC

Question 18

Which positive exam findings is indicative of a combined PLC and PCL injury?

Answer 18

Positive dial test at 30 and 90 degrees