Avascular necrosis in acute and acute-on-chronic slipped capital femoral epiphysis.

This study reviews the factors affecting the development of avascular necrosis (AVN) after slipped capital femoral epiphysis. Seventy-three patients (n=73) with ninety-two (n=92) hips were included in the study. Out of these 92, 16 were acute, 43 acute-on-chronic, 29 chronic, and four were preslips. Postoperative radiographs showed a reduction in 18 (19.5%) slips. The mean preoperative slip angle was 32 degrees (range 9-76) compared with the postoperative slip angle of 29.9 degrees (range 10-75 degrees ) (P=0.004). Four patients developed AVN. Our results showed that intraoperative reduction of the slip (P<0.001) was significantly related to the development of AVN and was also associated with poor functional outcome.