Osteochondroma of the femoral neck in Perthes disease.

Three out of 480 hips with Legg-Calve-Perthes disease have been found to have intraarticular osteochondroma-like lesions of the femoral neck. In all three cases, the osteochondroma unexpectedly diminished in size during the last phase of reossification and, therefore, did not require surgical excision. The occurrence of osteochondroma of the femoral neck with Perthes disease is rare, and resolution has not been previously reported.