[The clinical effect of total hip arthroplasty through direct anterior approach in the lateral decubitus position combined with proximal femur osteotomy for Hartofilakidis type C developmental dysplasia of the hip].

Objective: To evaluate the clinical effect of total hip arthroplasty through direct anterior approach in the lateral decubitus position combined with proximal femur osteotomy in the treatment of Hartofilakidis type C developmental dysplasia of the hip(DDH). Methods: A retrospective case series analysis of 134 patients (163 hips) with Hartofilakidis type C developmental dysplasia of the hip who underwent total hip arthroplasty at the Department of Orthopaedics, the First Affiliated Hospital of University of Science and Technology of China from January 2017 to December 2024 was performed. There were 10 males (11 hips) and 124 females (152 hips), aged (44.5±12.3) years (range:22 to 81 years), with the body mass index of (22.6±3.5) kg/m² (range:13.9 to 34.2 kg/m²). Harris hip scores and lower limb length discrepancy were compared between preoperative and final follow-up. Imaging stability of the prosthesis was evaluated by X-ray, and postoperative complications were recorded. The paired sample t-test or Mann-Whitney U test was used to compare data before and after surgery. Results: All patients successfully completed the surgery. The operation time(M(IQR)) was 125(35) min (range:80 to 200 min) and intraoperative bleeding loss was 200(100)ml (range:100 to 1 000 ml). All the patients were followed up for 36(22)months (range:16 to 100 months). Harris hip score increased from preoperative (44.7±5.6) points to (85.2±5.2) points at the last follow-up, and the difference was statistically significant (t=65.677, P<0.01). Lower limb length discrepancy decreased from preoperative 5(2)cm to 1(2) cm, and the difference was statistically significant (Z=15.777, P<0.01). All acetabular components were stable and free of displacement on imaging during follow-up. In 2 hips, the femoral osteotomy fragment had loosening and displacement after surgery and underwent revision surgery. In 2 hips, Vancouver type C periprosthetic fracture occurred, and they underwent open reduction and internal fixation. In 6 hips, dislocation occurred after surgery and all prostheses were in good position after closed reduction. At the last follow-up, 4 hips had local sensory abnormality in the affected lower limb. No dislocation, loosening, fracture, infection or neurovascular injury occurred in other patients. Conclusion: Total hip arthroplasty through direct anterior approach combined with proximal femur osteotomy for Hartofilakidis type C DDH can effectively improve hip joint function with satisfactory short-to-mid-term outcomes.