Osteochondritis dissecans of hip. A, Onset of Legg-Calvé-Perthes disease in 6-year-old patient. B, Fourteen months later, fragmentation and reossification stage. C, Persistent defect 5 years after onset. D, Osteochondritic lesion at 7 years with some evidence of healing. E, Lateral radiograph during same period shows osteochondritic lesion. Note air arthrogram with smooth cartilage surface. F, At 8 years defect is healing. G, Lateral radiograph at same time shows no evidence of defect.