To help to determine the natural history of residual dysplasia of the
hip after skeletal maturity, we followed the status of the contralateral
hip in 286 patients who had had a total hip replacement for osteoarthrosis
secondary to dysplasia. The initial radiographic findings in seventy-four
patients in whom advanced osteoarthrosis later developed in the
contralateral hip were compared with those in forty-three patients who had
reached the age of sixty-five years without having had severe
osteoarthrosis. No patient in whom the hip functioned well until the age of
sixty-five years had had a center-edge angle of less than 16 degrees, an
acetabular index of depth to width of less than 38 per cent, an acetabular
index of the weight-bearing zone of more than 15 degrees, uncovering of the
femoral head of more than 31 per cent, or an acetabulum in which the most
proximal point of the dome had been at the lateral edge (zero peak-to-edge
distance).