Sandwich method in Crowe type 4 hip arthroplasty surgery: a retrospective study on a novel technique for osteotomy...

In hip arthroplasties performed on patients with Crowe type 4 dysplasia, femoral shortening is often required to position the hip into the true acetabulum. Nonunion at the osteotomy site is one of the significant comorbidities in osteotomies that lower the hip into the true acetabulum. This study aimed to evaluate the clinical and radiological outcomes of hip arthroplasty with femoral shortening in patients with Crowe type 4 dysplasia using the technique we developed. This study retrospectively evaluated the outcomes of 96 (117 hips) patients who underwent subtrochanteric transverse shortening osteotomy due to Crowe type 4 dysplasia between January 2016 and December 2020, with a minimum follow-up period of 24 months. Harris Hip Score (HHS) was used for clinical evaluation of the patients, followed by comparison of preoperative and postoperative values. Radiological evaluation included assessments of union time, leg length discrepancy, and union rates. Intraoperative and postoperative complications were noted. The HHS had a mean preoperative value of 54.66 ± 7.47 and increased significantly postoperatively to a mean value of 93.82 ± 7.00 (P < .05). Changes in HHS (~39.2) surpass the minimal clinically important difference threshold. At the final follow-up, the union was observed in 115 (98.3%) hips. Despite a follow-up period exceeding 24 months, nonunion was radiologically observed in 2 (1.7%) hips. Our observations had relatively lower rates than those reported in literature. The preoperative and postoperative leg length discrepancies were measured as 5.03 ± 1.09 cm and 0.64 ± 0.74 cm, respectively (P < .05). Intraoperatively, femoral fractures were observed in 12 (10.3%) hips, dislocations in 5 (4.3%) hips, and sciatic nerve injury in 4 (3.4%) hips. In hip arthroplasties performed on patients with Crowe type 4 dysplasia, supporting the strut graft around the subtrochanteric transverse osteotomy site with cancellous bone taken from the trochanter major and femoral head reduces the risk of nonunion, and satisfactory clinical outcomes can be achieved with this method.