Slipped capital femoral epiphysis: long-term outcome and remodelling after in situ fixation

Purpose: In primary treatment of slipped capital femoral epiphysis (SCFE) in situ fixation reliably prevents slip progression. The aim of this study was to examine the long-term outcome of SCFE-patients treated by transfixation with Kirschner wires with a special focus on the remodelling process of the hips under this fixation method. Methods: 30 patients with stable SCFE (mean initial slip angle: 29 degrees, mean follow-up: 10 years), who were treated with bilateral transfixation by Kirschner wires, were recruited for this study. At most recent follow-up patients were clinically and radiologically (X-ray and MRI) examined. Medical records were reviewed for previous follow-up time points. Results: Range of motion: At most recent follow-up the mean range of motion was: extension/flexion: 0/0/121, abduction/adduction: 44/0/31, external rotation/internal rotation: 39/0/24. Nearly all dimensions of motion significantly improved during the postoperative course. Head-shaft angle: We saw a significant reduction of the mean head-shaft angle from 29 degrees preoperatively to 11 degrees at most recent follow-up (p<0.0001). Harris Hip Score (HHS): 24 patients had an excellent, 3 a good, 2 a fair and 1 a poor outcome defined by HHS. Remodelling: At most recent follow-up 25 patients achieved complete remodelling. The remodelling process took place especially during the first postoperative year. Angle alpha: The mean angle alpha of the affected hips at most recent follow-up was 62 degrees. Conclusions: Transfixation with Kirschner wires leads to very good clinical, functional and radiologic results with a low complication rate. Furthermore the femoral head-neck junction retains enough plasticity for an active remodelling process.