Which among the following is not a feature of the Unhappy triad of O' donoghue?

The most common mechanism of ligament disruption of the knee is adduction (valgus), flexion and internal rotation of femur on tibia which usually occur in spos in which the foot is planted solidly on the ground and leg is twisted by rotating body (i.e. football, soccer, basketball, skiing)The medial structures medial (tibial) collateral ligament (MCL) and medial capsular ligament are first to fail, followed by ACL tears if the force is of sufficient magnitude. The medial meniscus may be trapped between condyles and have a peripheral tear, thus producing unhappy triad of O' Donoghue.(Refer: GS Kulkarni Textbook of Ohopedics, 3rd edition, pg no.2565)