Acetabular Dysplasia in the Reduced or Subluxated Hip

Hip dysplasia with a located, or subluxed, femoroacetabular joint refers to inappropriate development of either the acetabulum, proximal femur or both. The resulting pathomorphologies damage the labrum/chondrolabral junction and articular cartilage leading to premature degeneration of the hip joint. Acetabular under coverage of the femoral head produces instability of the femoroacetabular joint which may result in excessive stress on the labrum and/or chondrolabral junction. With this in mind, surgical approaches are designed to preserve the hip joint, addressing the pathological mechanical problems presented by these developmental or disease processes. In doing so, the goals of hip joint preservation are to restore stable acetabular coverage of the femoral head, a near normal range of motion, without femoral acetabular/pelvic impingement. The purpose of this section is to review the pathologic processes of acetabular development that lead to, and the surgeries that correct, acetabular dysplasia in a located, or subluxated, hip. Emphasis is placed upon understanding how the developmental milestones of the acetabulum influence the surgeon’s decision to operate, and if so, whether to perform an acetabuloplasty, redirectional, salvage or replacement procedure.