Single screw fixation for acute and acute-on-chronic slipped capital femoral epiphysis.

Charts and radiographs of 78 patients with slipped capital femoral epiphysis were reviewed. During the retrospective study period, 1990 to 1993, 16 patients had acute or acute-on-chronic slips; 21 hips were involved. Nine hips were acute and 12 hips were acute-on-chronic slips. No patient reported endocrinopathy or other systemic illness. All hips were fixed with a single 7-mm cannulated screw. No attempts were made for reduction. The lateral head-shaft angle (preoperative, postoperative, and at followup) was measured as was the position of the screw (postoperative and followup). Physeal closure in 19 hips occurred at a mean of 9.6 months. Two additional patients did not return for followup until 30 and 36 months after surgery. At closure, there was no significant change in head-shaft angle from preoperative position. No cases of avascular necrosis or chondrolysis were seen in this series. Seventeen of the 21 hips had an excellent functional result. Three hips had a good result and 1 had a poor result. There was a tendency for poor pin position and less satisfactory results to be associated. It is concluded that single screw fixation is adequate for treating uncomplicated acute and acute-on-chronic slipped capital femoral epiphyses.