Acetabular Morphology in Patients with Developmental Dysplasia of the Hip with High Dislocation

PURPOSE: The current study aimed to investigate the morphology of the true acetabulum in developmental dysplasia of the hip (DDH) with high dislocation. A secondary was to evaluate the acetabular cup placement in patients with high dislocation who were treated with total hip arthroplasty (THA). MATERIALS AND METHODS: Using a retrospective design, 23 hips with DDH with high dislocation in patients who were treated with THA were included in this study. We measured the depth, width and thickness of the anterior and posterior walls of the original acetabulum using preoperative computed tomography images and investigated the cup size applied in these cases. RESULTS: The mean depth and width of the acetabulum was 18.4 and 16.2 mm proximal end, 18.4 and 24.3 mm in the middle, and 15.8 and 27.6 mm at the distal part. Mean thickness of the anterior and posterior walls was 10.9 and 23.9 mm at the proximal end, 10.3 and 22.2 mm in the middle, and 10.9 and 22.7 mm at the distal part. A 42-mm cup was using in one hip, a 46-mm cup in three hips, a 48-mm cup in 13 hips, and a 50-mm cup in six hips. CONCLUSION: In patients with Crowe IV DDH, the morphology of the acetabulum comprises a triangle that broadens from proximal to distal points, with a relatively thick posterior wall. Reaming the acetabulum posteriorly and inferiorly may enable the placement of a relatively larger cup to achieve stable fixation.