In an M.T.S. testing machine, medial and lateral tibial displacements and varus and valgus rotations of fresh, intact, young cadaver knee specimens were studied. For medial displacement, the anterior cruciate carried more of the load (50%) than the other knee ligaments while for lateral displacement the posterior cruciate carried the greatest percentage of load (31% compared to 27% carried by the medial collateral ligament). Coupled forces were recorded.

During medial tibial displacement, the anterior cruciate ligament exerted posterior forces on the tibia of 55% of the lateral force applied. During lateral tibial displacement, the posterior cruciate ligament exerted anterior force on the tibia which averaged 70% of the medial force applied. For 8° valgus rotation the medial collateral ligament carried more of the resistive moment (17% in one specimen and 55% in the other) than the posterior cruciate. For 8° varus the lateral ligaments contributed about 25% of the resistive moment. Studies of pedestrians whose knees have sustained lateral impacts show damage to anterior and posterior cruciate ligaments as well as to medial and lateral collateral ligaments. Long term exercise is necessary for maximum rehabilitation of these patients.