In brief: Crowe's classification: arthroplasty in developmental dysplasia of the hip.

THA was described as ‘‘The operation of the century’’ [13]. Despite success of the procedure for patients with idiopathic or traumatic degenerative arthritis, hip replacement for congenital dislocation or subluxation was controversial as late as the 1970s [3, 6, 8, 13]. Different anatomic characteristics observed on AP radiographs of the pelvis historically were used to assess the degree of acetabular dysplasia. These included acetabular angle of Sharp, center edge angle of Wiberg, acetabular index of depth to width as described by Heyman and Herndon [11], acetabular roof obliquity described by Massie and Howorth [14], femoral head extrusion index, lateral subluxation, and peak to edge distance [15]. Crowe et al. described a relatively simple method to determine degree of hip dysplasia in 1979 [4].