Ligament Tear
Ligament injuries are common in human joints during sports and trauma, and they put patients at risk for osteoarthritis soon after the injury. Ligament injuries can take many different forms, including a full tear, a partial tear, a stretch injury, or a functional change caused by an adjacent fracture. Whatever type of injury occurs, a certain sequence of events begins the degenerative cycle that leads to osteoarthritis.
The initial ligament injury is caused by a traumatic event that dislocates the joint. Injury to the capsule, fibrocartilage, and/or subchondral bone can occur alone or in combination with other joint structures. When the joint is stressed, the integrity of the joint is compromised, which affects the motion between the bones and alters the articular contact mechanics. The aberrant contact mechanics, together with the inflammatory cascade, affect the cartilage and underlying bone metabolism, disrupt the joint balance, promote wear, and increase shear stress. The joint's other structures are more vulnerable to injury as a result of the instability, exacerbating the condition.