Capital femoral epiphysis and growth plate of the asymptomatic hip joint in unilateral Perthes disease.

Radiograms of 173 children with unilateral Perthes disease were reviewed with particular reference to the presence of flattening and irregularity of the 'unaffected' epiphyses. The slope and shape of the growth plate were also evaluated. About 35% of children with Perthes disease showed changes of the unaffected proximal femur in the first radiograms of the hip joints. These consisted of small epiphysis, flattening of the epiphysis, contour irregularities (20%), and changes in the growth plate (15%). The radiographic abnormalities were not accompanied by any clinical symptoms of the asymptomatic hip joint and they receded with age during treatment.