Background Slipped capital femoral epiphysis (SCFE), causing posterior and inferior displacement and retroversion of the femoral head, is a well-recognized etiology for femoroacetabular impingement (FAI) and can lead to premature arthritis in the young adult. The treatment of malunited SCFE remains controversial. Surgical dislocation and subcapital correction osteotomy (SCO) has been described as a powerful method to correct the proximal femoral deformity. Methods Between January 2003 and January 2010, 11 patients (12 hips) with closed femoral physes and symptomatic FAI from malunited SCFE were treated with surgical dislocation and SCO. We performed a retrospective review of patient histories, physical exams, operative findings, and pre and postoperative anteroposterior (AP) and groin lateral (GLat) radiographs. Mean follow-up was 61 months. Results There were 4 female and 7 male patients with an average age of 15 years at the time of SCO. On the AP radiograph the mean inferior femoral head displacement (AP epiphyseal-neck angle) was significantly improved (-26° to -6°, p<0.001). On the groin lateral radiograph the mean posterior femoral head displacement (Lateral epiphyseal-neck angle) was significantly improved (-45° to -3°, p<0.001). The mean alpha angle was also significantly improved on both views (AP: 85° to 56°, P<0.001; GLat: 85° to 46°, p<0.001). Operative findings included one femoral osteochondral defect, 8 Outerbridge grade 3-4 acetabular cartilage lesions, and 10 labral lesions. Significant improvement of the mean Harris hip score (HHS) was seen at latest follow-up (54 to 77, p=0.016). Complications occurred in 4 of the 12 cases with AVN in two patients, a worse postoperative HHS in one patient, and failure of fixation treated successfully with revision open reduction internal fixation in one patient. Conclusions Subcapital correction osteotomy as an adjunct to surgical dislocation and osteochondroplasty can be used to correct the deformity of the proximal femur associated with malunited SCFE. Normalization of proximal femoral anatomy may postpone progression to severe osteoarthritis and thus delay the need for arthroplasty in this young patient population. However, surgeons and patients should be aware that the risks of this procedure in this population are significant.

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