Osteochondritis dissecans results from a loss of the blood supply to an area of bone underneath a joint surface and usually involves the knee. The affected bone and its covering of cartilage gradually loosen and cause pain. This problem usually arises spontaneously in an active adolescent or 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. A person with this condition may eventually develop osteoarthritis.
Lack of a blood supply can cause bone to break down (avascular necrosis). The involvement of several joints or the appearance of osteochondritis dissecans in several family members may indicate that the disorder is inherited.
Symptoms and Diagnosis
If normal healing doesn't occur, cartilage separates from the diseased bone and a fragment breaks loose into the knee joint, causing weakness, sharp pain, and locking of the joint. An x ray, MRI, or arthroscopy can determine the condition of the cartilage and can be used to diagnose osteochondritis dissecans.
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 cartilage growth. Research is being done to assess the use of cartilage cell and other tissue transplants to treat this disorder.
Source: National Institute of Arthritis and Musculoskeletal and Skin Diseases
Reviewed: May 2001
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