BILATERALITY IN SLIPPED CAPITAL FEMORAL EPIPHYSIS - IMPORTANCE OF A RELIABLE RADIOGRAPHIC METHOD

One hundred patients treated for slipped capital femoral epiphysis (SC FE) were reviewed to evaluate the incidence of bilateral slipping of t he epiphysis at an average follow-up time of 32 years. When the patien ts were examined during adolescence, repeat lateral radiographs of the hips had been obtained by the frog lateral view in 33 patients and by the standardized lateral view according to the method of Billing in 6 7 patients. At re-examination, 59 patients (59%) were judged to have h ad a previous bilateral SCFE; in 42 of these 59 patients (71%), slippi ng of the contralateral hip was asymptomatic. In 23 patients (23%), th e diagnosis of bilateral slipping was established at primary admission , in 18 (18%) later during adolescence, and in 18 (18%) not until the patients were reexamined as adults and the primary radiographs were re viewed. The incidence of bilateral slipping was higher in patients in whom the Billing standardized lateral view was used (63%) than in pati ents in whom the frog lateral view was used (52%). We conclude that th e incidence of bilateral slipping of the epiphysis in patients with SC FE is similar to 60% in Sweden. If repeat radiographs of the contralat eral hip are obtained with the Billing standardized lateral view until physeal closure occurs, even minor slipping of the epiphysis, which i s often advisable to treat, will be apparent.