Femoral neck bone mineral density after resurfacing hip arthroplasty

Introduction: Resurfacing hip arthroplasty (RHA) has been suggested to provide an alternative to conventional total hip arthroplasty in younger, active patients. It seems to have an ability to conserve the bone mass on the femoral side. Some controversy exists regarding to the possible disadvantages of RHA and some of them are connected to poor femoral bone quality after surgery. Hence we wanted to study the bone mineral density changes 3 and 12 months after RHA. Materials and Methods: A total of 26 patients (22 men and 4 women, 28 hips) underwent a hip resurfacing arthroplasty. The mean age of the patients was 55,2 (range 38-69) years. Bone mineral density (BMD) of the proximal femur was measured by using the dual-energy X-ray absorptiometry (DXA) postoperatively and within 3 and 12 months from surgery. For analysis, we divided the femoral neck area into four equal-sized regions of interest ranging from the prosthesis to the trochanter level. Results: At three months follow-up the BMD changes varied between -5.1% (ROI C) and + 1.9% (ROI A), as compared with the immediate postoperative values. After one year follow-up the BMD changes were + 1.1% in the ROI A, + 5.4% in the ROI B, -3.9% in the ROI C and + 1.3% in the ROI D. The changes in BMD were not statistically significant. Discussion: While there is still much debate and room for additional research in this topic, the results suggest that BMD is conserved in the femoral neck one year after hip resurfacing arthroplasty.