Relative role changing of lateral collateral ligament on the posterolateral rotatory instability according to the knee flexion angles: a biomechanical comparative study of role of lateral collateral ligament and popliteofibular ligament.

Purpose: This cadaveric study assessed the relative role of the lateral collateral ligament (LCL) and popliteofibular ligament (PFL) in limiting tibia external rotation.

Methods: Eight paired cadaveric knees were divided into two groups. The specimens were mounted on a rotational wheel and 5 Nm external rotation torque was applied before and after cutting the ligaments at 0°-30°-60°-90° knee flexion.