Anatomy

Question 1

what are the lateral structures of the knee by layers

Answer 1

lateral knee consists of 3 layers:
* layer one - most superficial - iliotibial tract and biceps femoris
* layer two - patella retinaculum and ligament
* layer three:
* superficial - LCL , anterolateral lig
* Deep - arcuate ligament, popliteus tendon and popliteofibular ligament

common peroneal nerve between layers 1 and 2
lateral geniculate artery between superficial and deep layers of layer III

Question 2

what is the function of the PLC and how is it commonly injured?

Answer 2

Posterolateral corner
Resists:
* external rotation - primary stabiliser
* posterior translation - secondary stabiliser
* varus strain

commonly injured by:
* dislocation - multiligament injury
* varus injury in flexed knee
* ER twisting knee

Question 3

what clinical test would you perform to detect a PLC injury?

Answer 3

Dial test
* >10 deg ER at 30deg flexion = PLC injury
* >10deg ER at 90deg flexion = combined PLC and PCL injury

Varus strain of the knee
* 30 deg - varus opening = LCL injury
* 0 deg - varus opening = PLC and cruciate injury

Gait
varus thrust

Question 4

what are the medial structures of the knee?

Answer 4

Consists of three layers
* layer 1 - superficial - sartorius and patella retinaculum
* layer 2 - semimembranous, superficial MCL & MPFL
* layer 3 - deep MCL, capsule and coronary ligament

gracilis, semiT and saphenous nerve run between layers 1 and 2

Question 5

what is the medial approach to the knee and when would you use it?

Question 6

what is the lateral approach to the knee and when would you use it?