Voluntary rotation in the human knee joint.

The structures responsible for the restriction of knee joint rotation were established by means of sequential destruction of the menisci, cruciate ligaments, capsular and collateral ligaments; the capsular and collateral ligaments restrict both medial and lateral rotation. The anterior cruciate ligament was also found to restrict medial rotation, thus acting as a synergist to the capsular and collateral ligaments. The posterior cruciate ligament was found to have no effect on rotation. Under no circumstances do the cruciates as a pair restrict medial rotation as this is drastically increased as a consequence of the removal of the capsular and collateral ligaments, and the lateral meniscus. The axis of medial rotation ran through the medial tubercle of the intercondylar eminence while that of lateral rotation was located slightly lateral to it.