Torsion of knee results in injury most commonly to :

D i.e. Tibial collateral ligament Most knee ligament injuries occur while the knee is bent i.e. when the capsule and ligaments are relaxed and the femur is allowed to rotate on tibia. Injury to the medial (tibial) collateral ligament is the most common knee ligament injuryQ The medial structures are most often affected but if the injury has a twist in addition to a valgus force the ACL may also be damaged. The twisting force in a weight bearing knee often ters the medial meniscus, causing a well recognized trid of MCL, ACL, and medial meniscus injuryQ. ("unhappy traid of 0' Donoghue")