Fig. 2

Example case of a 42-year-old male patient. This patient had left Crowe type IV DDH and a Harris hip score of 42 points. a1–a2 Preoperative pelvic radiograph showing significant superior dislocation of the left femoral head forming a joint with a false acetabulum, left DDH, and subtrochanteric PFD. b1–b2 Immediate postoperative AP pelvic and lateral femur radiographs after total hip arthroplasty with osteotomy and modular S-ROM prosthesis, resulting in acetabular cup implantation at the true acetabulum level, with excellent intramedullary filling of the prosthesis, and fixation effect of intramedullary nail at the proximal and distal osteotomies by the distal and proximal segments of the prosthesis. c1-c2 At 3 months postoperatively, the AP pelvic and lateral femur radiographs showed that the femoral osteotomy was in the stage of osteophyte formation and the prosthesis stem was well filled. d1–d2 At 9 months postoperatively, the AP pelvic and lateral femur radiographs showed that the acetabular and femoral prosthesis were stable, and the femoral osteotomy continued to heal. e1–e2 AP hip radiographs at 3 years postoperatively showed good position of the prosthesis (without prosthesis subsidence), excellent healing of the osteotomy surfaces, and no limb-length discrepancy. d Lateral radiograph taken at 1 year postoperatively. Note: DDH, developmental dysplasia of the hip; PFD, proximal femoral deformity; AP, anteroposterior