Analysis of the Development of Avascular Necrosis in Slipped Capital Femoral Epiphysis

Introduction: Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents. The most serious complication is avascular necrosis (AVN), which has lasting sequelae. The objective of this study was to determine the rate of AVN in stable slips. Method: We reviewed retrospectively all the children treated for SCFE between 2004 and 2008 at Princess Margaret Hospital. Results: Of a total of 67 patients, 51 (76%) were stable slips and 16 (24%) unstable. Avascular necrosis developed in 3 patients with stable slip (5.9%) and in 6 with unstable slip (37.5%). There was no statistically significant association found between AVN and age, weight, slip severity, pin position, number of pins used, experience of the surgeon or side affected. Those with stable presentations can develop AVN2, males are more likely and the possibility of developing AVN increases as the time from presentation to operation increased. Conclusion: AVN can occur in stable slips without joint penetration. This combined with male sex and increased time to operation, increases the risk of AVN.