AVASCULAR NECROSIS IN ACUTE AND ACUTE-ON-CHRONIC SLIPPED CAPITAL FEMORAL EPIPHYSIS.

Abstract

Aim:This study was carried out to assess various factors responsible for the development of avascular necrosis and the effect of treatment on clinical outcome.

Methods: We studied the clinical notes and radiographs of patients presenting with SCFE during the period between 1994 and 2003.

Results: Seventy three patients (n=73) with ninety two (n=92) hips were included in the study. There were 16 acute, 43 acute-on-chronic, 29 chronic and 4 preslips. Seventy Seven (n = 77) slips were classified as stable and 15 as unstable slips. Fifty three slips (57.6%) were mild, 34 (37%) were moderate and five (5.4%) were severe slips. Despite no deliberate attempts to reduce the slip at the time of surgery eighteen hips (n=18) showed a median decrease in slip angle of 8 degrees (range 2–36) in acute and acute-on-chronic slips. The mean preoperative slip angle was 32 degrees (range 9–76) compared to postoperative slip angle of 29.9 degrees (range 10–75) (p=0.004). Four patients developed avascular necrosis (AVN). Intraoperative reduction of the slip was significantly related to development of AVN (p< 0.001). According to the criteria of Heyman and Herndon eight patients had functional deficit at the time of final follow up and clinical outcome was fair, poor or failure. All of these patients had a reduction in the angle of slip at the postoperative radiographs compared to their preoperative radiographs.

Conclusion: Reduction of slipped capital femoral epiphysis is responsible for poor outcome and also related to the development of avascular necrosis. We recommend single in situ pinning for these cases regardless of severity of slip.