Residual femoral deformity and femoroacetabular impingement after intertrochanteric osteotomy for slipped capital femoral epiphysis

We retrospectively reviewed 29 hips in which intertrochanteric osteotomies were performed for severe slipped capital femoral epiphyses. Mean age at surgery: 12.6 years. Mean follow-up period: 6 years. At the final follow- up evaluation, one patient had coxalgia, and six hips showed a limited range of motion. A pistol-grip deformity was observed in 13 hips, osteoarthritis in two hips, and a bump existed in 19 hips on the latest radiographs. Gradual remodeling of the bumps was observed post-operatively in 22 hips. The mean a and β angles and offset a and β improved over time. The remodeling proceeded rapidly for 1 year post-surgery. We compared hips classified as β angles of ≥ 63° to < 63° at the final follow-up evaluation, the mean β angle 1 year post-surgery, and the mean ratio of improvement of the β angle per year from 1 year post-surgery to the final follow up, which differed significantly. Nearly all of the patients who underwent intertrochanteric osteotomies had residual morphologic abnormalities, but few had clinical symptoms. The β angle 1 year post-surgery and the ratio of remodeling of the bump from 1 year post-surgery to the final follow-up can be regarded as a potential predictor of morphologic results after intertrochanteric osteotomy.