Congenital dislocation of the hip. The fate of the well-developed acetabulum.

In a previous study of 177 hips treated in infancy for congenital dislocation and followed for 10 to 27 years, all were found to have well-developed acetabula. Nevertheless, there were two cases with minimal arthrotic changes. In this paper, a further study of 107 of these hips, with a follow-up of 15 to 30 years, indicates that the number of hips with arthrotic changes has increased. Attention was given to the fate of the acetabulum in relation to its depth or shallowness as measured by the CE angle. It is concluded that a hip with a slightly shallow acetabulum (CE angle, approximately 20 degrees) is less susceptible to wear or deterioration than a hip with a deeper acetabulum (CE angle, greater than 25 degrees).