We have previously reported on 57 patients (60 hips) with a past history of Legg-Calvé-Perthes' disease at a mean of 34 years after the onset of symptoms. From this original group, 48 patients (51 hips) were also available for review after a mean of 50.2 years. We consider that the best prognostic indicator for the hip is the shape of the femoral head at skeletal maturity. Normal or flattened spherical heads present few problems. Irregular or very irregular heads are associated with a poor outcome.