Treatment positions for congenital dysplasia of the hip.

Fetal and infant hips were analyzed in an attempt to explain some of the observed complications (particularly avascular necrosis) encountered in the treatment of hip dysplasia. Gross manipulation showed a tight interlocking of the acetabular labrum into the intertrochanteric notch of the proximal femur in the commonly used treatment positions that emphaized positional extremes. Injection studies corroborated vascular occlusion at three major sites when such positions were maintained. Marked abduction appeared to be the important position to avoid during treatment.