Post-traumatic osteoarthritis after ACL injury.

Post-traumatic osteoarthritis (PTOA) occurs as a consequence of joint trauma or occupations or sports that subject joints to excessive loading stresses. Ligament injuries to the knee, particularly tears of the anterior cruciate ligament (ACL), often result in PTOA. Approximately half of the individuals with an ACL injury develop PTOA regardless of the reconstruction of the torn ligament. This observation has raised the possibility that other injuries occur to the knee in association with ACL tears that may involve ligamentous capsular structures, articular cartilage, or subchondral bone. Many ACL injuries occur in noncontact sports and are the result of biomechanical abnormalities. Female athletes are more likely than their male counterparts to suffer ACL injuries. This review outlines the epidemiology of ACL tears, its pathology in cartilage and bone, some of the demographic, biomechanical, and neuromuscular factors involved in ACL tears, and PTOA and important information gained from preclinical injury models.