Placement of Standard Sized Acetabular Cup Between True and False Acetabulum in Patients with Crowe III/IV Dysplasia: A Safe Option in THA Without Femoral Osteotomy.

INTRODUCTION: There is no consensus in literature on the surgical treatment of patients with Crowe type III/IV patients. Each arthroplasty procedure has its own advantages and disadvantages. In this study by placing the acetabular cup between the true and false acetabulum, we aimed to share our experience about criteria of patient selection, surgical technique, and mid-term results of THA (total hip arthroplasty) in which the risk of dislocation was minimized using a standard-sized acetabular cup.

MATERIALS AND METHODS: We reviewed the clinical and radiographic data of the patients with Crowe type III/IV treated by cementless THA without femoral shortening osteotomy from January 2015 to January 2020. The clinical (Harris hip score, Trendelenburg sign, limb lengths) and radiographic (AP/L hip X-ray, 3D CT) examinations before surgery; 1, 3 months and 1 year after the surgery were evaluated. All postsurgical complications were noted.

RESULTS: Among all, 268 patients met the inclusion criteria. Thirty-two patients (11.9%) were male and 236 (88.1%) were female. Mean age was 46.8 years. Mean follow-up duration was 42.4 (26-57) months. Mean Harris Hip score (HHS) was 49.7 and Trendelenburg sign was positive in all patients preoperatively. In the final evaluation, mean HHS significantly improved to 80.2 ( p  < 0.005) and none of the patients had Trendelenburg sign. Mean lengthening of the operated leg was 4.3 cm.

CONCLUSION: Total hip arthroplasty with placement of acetabular cup between true and false acetabulum can be successfully preferred in selected patients with Crowe III/IV dysplasia.