Osteochondritis dissecans (and often abbreviated to OCD or OD) is a joint disorder in which cracks form in the articular cartilage and the underlying subchondral bone. OCD is caused by blood deprivation in the subchondral bone. This loss of blood flow causes the subchondral bone to die in a process called avascular necrosis. The bone is then reabsorbed by the body, leaving the articular cartilage it supported prone to damage. The result is fragmentation of both cartilage and bone, and the free movement of these osteochondral fragments within the joint space, causing pain and further damage...