Avascular necrosis after open reduction for congenital dislocation of the hip: analysis of causative factors and natural history.

We analysed the causative factors and natural history of avascular necrosis (AVN) after open reduction of 87 dislocated hips. AVN was observed in 37% of the hips, yet open reduction did not appear to contribute to the development of AVN and its prevalence was similar in hips treated by open or closed reduction in our institution. Only 45% of hips with AVN had a good late result. More containment procedures were required if AVN had occurred. Premature physeal closure was one late manifestation of this complication, which occurred following apparent partial AVN changes.