Total hip arthroplasty with subtrochanteric femoral shortening osteotomy using a monoblock cylindrical cementless stem for severe developmental hip dysplasia (Crowe type III, IV).

Background: Treatment of patients with Crowe type III and IV dislocated hips is challenging because of the hip deformity in these patients. In addition to the usual total hip replacement, shortening and reduction of the femur are often required. We herein report on our surgical technique using a monoblock cylindrical cementless stem and a direct lateral approach.

Methods: This study included patients with a diagnosis of severe developmental dysplasia of the hip (Crowe types III and IV) who underwent primary total hip arthroplasty at our hospital from August 2019 to January 2022. Eleven hips of seven patients were treated. All patients underwent horizontal osteotomy using a monoblock cylindrical cementless stem and a direct lateral approach. Complications such as dislocation, infection, and implant dropout were evaluated. In addition, the clinical assessment included the hip range of motion at the last observation and hip function based on the Japanese Orthopaedic Association (JOA) hip score and the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ).

Results: The average operation time was 224 min (range, 194-296 min), and the average bleeding amount was 396.1 g (range, 20-1010 g). The main complications were acetabular implant dislocation, postoperative dislocation, intraoperative arterial injury, intraoperative proximal femoral fracture, subsidence of femoral implant. and postoperative pulmonary infarction, which occurred in one patient each.

Conclusion: Total hip arthroplasty for Crowe type III and IV hips is associated with various surgical technical difficulties because of its anatomical characteristics. While patients with severe osteoporosis are contraindicated, the use of a cylindrical monoblock cementless stem and the direct lateral approach makes it possible to simplify the procedure for shortening the femur and increase the indications for surgery.

Level of evidence: Therapeutic Level Ⅳ.