Answers on ACL Injuries, Retear Risk, Rehab, Return to Sport and Injury Prevention from the World's Leading Long-Term Study

Anterior cruciate ligament (ACL) injuries are among the most frequent musculoskeletal (muscle and bone) injuries suffered by physically active people. About one in 3,000 people suffer an ACL injury.

Injuring your ACL causes immediate pain and knee instability along with potentially reduced athletic abilities. An estimated 300,000 ACL reconstructions are done annually in the United States. Despite many advances in surgery and rehabilitation, regaining previous function is not guaranteed.

Long-term, an ACL injury increases your chance of reinjuring both knees. It also increases 10-fold your risk of suffering osteoarthritis and long-term disability.

What is MOON Knee Group and Why This Website?

Established nearly 20 years ago, the Multicenter Orthopaedic Outcomes Network (MOON) Knee Group is one of the world’s leading resources on ACL injuries, reconstruction, rehabilitation and injury prevention. It is the first and only research group to enroll and follow several thousand ACL reconstruction surgery patients with nearly 80 percent follow-up at two, six and 10 years.

There are more than 3,500 cases in the study, which has resulted in more than 65 peer-reviewed papers published in leading medical journals with thousands of citations.

The group’s mission is to answer critical questions about ACL injuries and improve treatment outcomes. The results have changed ACL injury treatment.