Good Long-Term Clinical Outcome in 50% of Hips With Mild and Moderate Chronic Slipped Capital Femoral Epiphysis Treated With in Situ Fixation: 93 Hips With a Follow-up of 50 Years.

Abstract

There is no consensus regarding the initial treatment of slipped capital femoral epiphysis (SCFE). The aim of this study was to analyze the long-term outcome of in situ fixation (ISF) in chronic SCFE. The study consisted of 79 patients (93 hips), treated with ISF from 1955 to 1993. There were 47 male patients (59%) and 32 female patients with a mean age of 12.8 years (range, 8-16 years) at the time of diagnosis. The mean slip angle was 33.4° (range, 12°-80°). The slip was mild (<30°) in 46 hips (49%), moderate (30°-49°) in 33 (36%), and severe (≥50°) in 14 hips. Long-term clinical outcome was based on the rate of total hip arthroplasty (THA) and the modified Harris Hip Score (mHHS) analyzed by telephone (maximum score 91 points). The mean follow-up time was 51.6 years (range, 30-68 years). Thirty-two hips (34%) had undergone THA at a mean patient age of 55.9 years (range, 21-75 years). The survival rate (percentage of hips that had not undergone THA) was 99% at 20 years of follow-up and fell to 69% (95% confidence interval, 58%-80%) at 50 years. The mean mHHS in 57 of the 61 hips that had not undergone THA was 80.7 points (range, 22-91 points). Good long-term outcome, defined as no THA and mHHS ≥76 points, occurred in 40 of 89 hips (45%). The outcome was worse in hips with severe slips compared with moderate and mild slips (p = 0.020), whereas there was no significant differences between moderate and mild slips (p = 0.817). The only independent risk factor of outcome was high alpha angle. At a mean follow-up of 50 years, the clinical outcome in hips with mild or moderate slipping was good in 50% of the hips, and 27% had been converted to THA. These results are well suited for comparison with future studies of more modern treatment concepts. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.