ISOLATED OR PREDOMINANT BONE-CYSTS OF THE FEMORAL-HEAD

By definition, the signs of osteoarthritis in this context are absent or minor. Isolated or predominant bone situated anywhere in the femora l head, are more or less well demarcated and occasionally multiple or multilocular. They affect men three times more frequently than women w ith a mean age of 34 years. Painful disability is generally moderate a nd intermittent for many years. Limitation of movement is minor or abs ent. The clinical course is very slow and rarely required surgical tre atment. Aetiology : in the 23 cases observed over a period of 20 years , two thirds involved a dysmorphic femoral head : coxa plana, polyepip hyseal dysplasia, osteochondritis dissecans, occasionally associated ; three cases were due to excessive pressure (dysplasia or subluxation without signs of osteoarthritis). The other possible causes were juxta -articular bone cyst, chondroblastoma, giant cell tumour and clear cel l chondrosarcoma.