The effectiveness of mono or combined osteoporosis drug therapy against bone mineral density loss around femoral implants after total hip arthroplasty

Several previous studies have reported that bone mineral density (BMD) loss around femoral implants is a common outcome, particularly in the proximal femur, after total hip arthroplasty (THA). The purpose of this study was to investigate the effectiveness of alendronate monotherapy and combined therapy using alendronate and alfacalcidol for BMD preservation around femoral implants after primary THA. This study series included 60 patients who were classified into monotherapy (alendronate alone) (n = 18), combined-therapy (alendronate and alfacalcidol) (n = 20) or non-medication (n = 22) groups. The periprosthetic BMD and profile of the biochemical markers such as bone-specific alkaline phosphatase and serum N-terminal telopeptides of type-1 collagen (NT_X) were measured at 1, 12, 24 and 48 weeks after surgery. The BMD values in the region of the calcar of monotherapy and combined-therapy patients were maintained and were significantly higher than those of non-medication patients at each measurement period. The plasma levels of NT_X in the monotherapy and combined-therapy groups were found to be significantly lower than those in the non-medication group at each measurement period. In conclusion, the monotherapy and combined-therapy regimens significantly prevent periprosthetic BMD loss around femoral implants, most notably in the calcar, compared to no medication.