Meyer's dysplasia : delayed ossification of the femoral head as a differential diagnosis in perthes' disease.

Meyer's dysplasia strongly mimics Legg-Calve-Perthes' disease despite differing markedly in eventual outcome. This study presents the clinicoradiologi-cal features which differentiate it from Perthes' disease in a group of 178 children with a preliminary diagnosis of Perthes' disease, of whom nine were subsequently diagnosed with Meyer's dysplasia. All had a near normal development of the femoral head; mild flattening was seen in two cases. Clinical initial presentation often resembles Perthes' disease. However, the presence of a granular aspect of the femoral head, often bilateral, in a male child with a preliminary diagnosis of Perthes' disease should alert the clinician to the possibility of Meyer's dysplasia. Restitution of normal capital architecture is usual; there may however be a mild residual hypoplasia.