Although there is a high level of evidence that hip resurfacing arthroplasty preserves bone mineral density and bone stock in the proximal femur, the clinical relevance should be weighed against potential disadvantages, such as a higher revision rate for metal-on-metal bearings, according to researchers.
To determine whether bone mineral density (BMD) was preserved without significant femoral neck narrowing (FNN), the researchers randomly assigned 42 patients who needed primary hip arthroplasty for osteoarthritis to receive hip resurfacing (RHA) and 40 patients to small-diameter metal-on-metal total hip arthroplasty (MoM THA). The researchers measured BMD in the calcar with dual-energy absorptiometry (DXA) preoperatively; at 3 and 6 months; and at 1, 2, 3 and 5 years postoperatively. The researchers also measured four additional BMD regions of interest, as well as FNN after RHA.
Overall, the resurfacing procedure had a significantly longer mean time of surgery vs. THA. At 1-year follow-up after RHA, results showed BMD in the calcar increased to 106.8% and remained stable at 5 years. The researchers found a significant decrease in the corresponding region of interest in the THA to 80.5% at 1 year, which stabilized to 82.5% at 5-year follow-up. 