Is there a role for controlled repositioning and mini-open primary osteoplasty in the management of unstable slipped capital femoral epiphysis?

The management of unstable slipped capital femoral epiphysis is controversial with variable rates of avascular necrosis (AVN). Treatment options include in-situ stabilization, gentle/positional reduction and screw fixation and modified Dunn's procedure (MDP). We present a technique of controlled repositioning (CRP) of the epiphysis to pre-acute slip stage, screw fixation and primary osteoplasty. Between 2015 and 2020, 38 unstable slips were treated in our institution. Of these, 14 underwent successful CRP and the rest were treated with MDP. All the 14 patients who had CRP and completed 1-year follow-up were included for this study. The head-neck angle (HNA) was measured at presentation and alpha angle, head-neck offset and AVN were assessed during follow-up. The average age was 14 years (9-18) and mean follow-up was 17.7 months (12-43). The average intraoperative flexion internal rotation before osteoplasty was -18.5 degrees (-40 degrees to -5 degrees) which improved to +22.1 degrees (+15 degrees to +30 degrees). The average preoperative HNA was 48.7 degrees (34.1 degrees to 70.7 degrees) which improved to 18.4 degrees (1.8 degrees to 35.7 degrees) post-operatively. At final follow-up, the average alpha angle and head-neck offset were 46.4 degrees (30.9 degrees to 64.6 degrees) and 0.22 (0.09 to 0.96), respectively. The AVN rate in the CRP group was 7.1% compared with 20.8% in the MDP group, which was not significant (P = 0.383). Two patients had screw breakage. CRP, screw fixation and mini-open primary osteoplasty is a feasible treatment option in a subgroup of patients with unstable SCFEs. The limitation with this technique is that the final decision is made intraoperatively, and hence the patient and parents need to be counselled and consented appropriately. Level of evidence: Level IV-Case series.