Value of the head-at-risk concept in assessing the prognosis in Legg-Calvé-Perthes disease.

Seventy-five hips affected by Legg-Calvé-Perthes disease were reviewed. Three therapeutic groups were defined: conservative treatment, marrow emptying of the femoral neck, and varus derotation femoral osteotomy. Results were analyzed according to head-at-risk concept. Patients with head not at risk had better results regardless of treatment. Results in other groups were worse, but improved significantly with varus derotation femoral osteotomy. In children greater than 9 years of age, the results were almost invariably poor, irrespective of head-at-risk designation.