 Meta-analysis shows that in acute injuries of the ACL associated with a meniscus tear, 44% were of the medial meniscus, whereas 56% were of the lateral meniscus; in chronic ACL insufficiency, 70% were medial whereas 30% were lateral.Injury

Because the medial collateral ligament resists widening of the inside of the knee joint, the ligament is usually injured when the outside of the knee joint is struck.This force causes the outside of the knee to buckle, and the inside to widen.