Functional Outcome of Stable Grade III Slipped Capital Femoral Epiphysis Treated With In Situ Pinning

Background: We sought to determine the functional outcome of patients with grade 3 slipped capital femoral epiphysis who had been treated with in situ pinning at a mid-term follow-up. Methods: One hundred and five patients with 129 slips (24 bilateral) were reviewed. Minimum follow-up was 5 years and mean follow-up was 66 months. Slips over 60 degrees were considered grade 3. All of the patients underwent in situ pinning with a single cannulated screw; the placement of the screw was evaluated with the criteria of Stambough. The final evaluation was performed using the Iowa Hip Score and results were analyzed by sex, age at time of diagnosis, and body mass index. Statistical analysis was carried out using the Mann-Whitney U-test considering a P value of less than 0.005 to be statistically significant. Results: The mean Iowa Hip Score was 84.73. Fifty-two patients were considered to have an excellent result, 28 a good result, 16 a fair result, and 9 a bad result. The pin placement was considered adequate in 89 patients and inadequate in 16 patients. Forty-three patients were girls and 62 were boys and no statistical difference was found in function by sex. The mean Iowa Hip Score for patients under 12 years of age (n=20) was 85.8, for those between 12 and 15 years of age (n=69) it was 82.8 and for those over 15 years of age (n=16) it was 82.5 (P=0.003). There were 10 complications, all in the group in which the pin placement was considered inadequate, and all of these were considered fair or poor results. Conclusions: The functional results in the mid-term for patients with grade 3 slips treated with in situ pinning were generally good or excellent; a better result was found in patients below 12 years of age. A good or excellent result can be expected when pin placement is adequate and no complications arise.