Abstract
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.