Current concepts regarding the anterior cruciate ligament.

In an athlete, the torn anterior cruciate ligament (ACL) is best managed by surgical reconstruction. The failure to recognize an acutely torn ACL and the resulting inappropriate treatment can result in additional irreversible damage to the athlete's knee. Yet, as recently as 1983, a report documented that physicians failed to diagnose acutely torn ACLs in 93% of 103 patients who were subsequently seen with symptomatically unstable knees. Persistent instability is manifested by paroxysmal anterior shifts of the tibia on the femur during pivotal maneuvers, which may cause further irreparable damage. The injury has commonly gone unrecognized despite the fact that knowledge of the ACL's function, mechanism of its injury, and clinical presentation when torn can often lead to a strong suspicion of a torn ACL through history-taking alone. Documentation of hemarthrosis and a poor end point to passive tibial anterior displacement on the femur while the knee is between 10 degrees and 30 degrees of flexion confirms the diagnosis. Arthroscopically aided intra-articular reconstruction has emerged as the favored technique over extra-articular and combined intra-articular/extra-articular procedures. The bone-one-third patella tendon-bone autogenous graft remains the standard to which other graft materials are compared in reconstructing the ligament. Allograft reconstruction offers similar results with less postoperative morbidity and is reasonably safe; the spread of human immunodeficiency virus from donor to patient remains a remote possibility.