Osteochondritis dissecans is an aseptic necrosis of subchondral bone and articular cartilage, correctly classified with the group of osteochondroses known by the eponyms Legg-Calve-Perthes' disease, Kohler's disease, and Kienbock's disease. This specific type of lesion was recognized, described as an entity, and named long before the disease was sufficiently well defined to permit selection of an accurately descriptive term. The designation osteochondritis dissecans, first recommended by Konig in 1905 (4), inaccurately suggests an, inflammatory pathogenesis, but prolonged popular use has given it universal acceptance. Osteochondritis dissecans occurs most frequently in the weight-bearing joints which are most often subjected to trauma. The earliest reports refer to involvement of the femoral condyles of the knee, probably the most frequently traumatized articular surfaces. More recently, osteochondritis dissecans has been reported in many other sites. Although this form of osteochondrosis has a remarkably...