These observations reveal that joint instability resulting from ACL injury rapidly results in degenerative changes characteristic of those seen in idiopathic OA at arthroplasty and in experimental OA following ACL surgery. These changes may contribute to the development of post-traumatic OA that is commonly observed following ACL injury. The observations support and extend conclusions from other studies on human and animal articular cartilage and synovial fluids post-ACL injury that have revealed a rapid onset of damage to type II collagen and an initial increase in proteoglycan content characteristic of experimental OA post-ACL injury. This study provides direct evidence for the rapid development of degenerative changes characteristic of OA following ACL injury.

Oral contraceptive pill use yielded statistically significant decreases in anterior translation of the tibia as compared with nonusers. The OCP may have a role to play in the prevention of ACL injuries by prophylactically targeting 1 of the variables responsible for the increased ACL injury rates in women.