vunderneath a joint surface and usually involves the knee. The affected bone and its covering of cartilage gradually loosen and cause pain. A person with this disruption of the joint may eventually develop osteoarthritis. This disorder usually arises spontaneously in an active adolescent or a young adult. It may be due to a slight blockage of a small artery or to an unrecognized injury or tiny fracture that damages the overlying cartilage.

The bone undergoes avascular necrosis (degeneration from lack of a blood supply). 2 The involvement of several joints or the appearance of osteochondritis dissecans in several family members may indicate that the disorder is inherited.

What Are the Symptoms of Osteochondritis Dissecans? How Is It Diagnosed?
If spontaneous healing doesn't occur, cartilage eventually separates from the diseased bone and a fragment breaks loose into the knee joint, causing locking of the joint, weakness, and sharp pain. An x ray, MRI, or arthroscopy can determine the condition of the cartilage and be used to diagnose osteochondritis dissecans.

How Is Osteochondritis Dissecans Treated?
If cartilage fragments have not broken loose, a surgeon may fix them in place with pins or screws that are sunk into the cartilage to stimulate a new blood supply. If fragments are loose, the surgeon may scrape down the cavity to reach fresh bone and add a bone graft and fix the fragments in position. Fragments that cannot be mended are removed, and the cavity is drilled or scraped to stimulate new growth of cartilage. Research is currently being done to assess the use of cartilage cell transplants and other tissues to treat this disorder.