CHILDREN: Avascular necrosis as a complication in the management of developmental dysplasia of the hip

Avascular necrosis (AVN) of the proximal femoral epiphysis is an iatrogenic complication of treatment for developmental dysplasia of the hip (DDH), and does not occur during the natural history of the untreated hip. The objective is to produce a congruous concentric joint and minimize premature degenerative disease and disability during young adult life, by achieving early reduction of the hip with acetabular augmentation or femoral realignment when necessary. AVN causes a spectrum of damage to the epiphysis and physis and the classi¢cation by Kalamchi and MacEwen is in wide usage. The signi¢cant late sequellae of AVN are abnormal contour of the femoral head and neck which contribute to subluxation of the hip, a short femoral neck causing abductor insu⁄ciency and leg length inequality. It may be a devastating complicationwhich can result in a poorer outcome than the original pathology of DDH, and is particularly disastrous if the previously normal contralateral hip is a¡ected.