Bisphosphonate treatment for osteolysis in total hip arthroplasty. A report of four cases.

Aseptic loosening due to wear debris is the most frequent modality of failure in total hip arthroplasty. Bisphosphonates, a class of molecules which inhibit bone resorption showed an inhibitory effects on particles-induced osteolysis in vitro and in animal models. We report the clinical, radiographic and densitometric outcome of four postmenopausal women with total hip arthroplasty affected by peri-prosthetic osteolysis treated with neridronate due to their unwillingness to be operated. After neridronate treatment, there was general improvement in pain and function: VAS decrease 13 points (15%), the Harris Hip Score increase 9 points (15%). An average number of 3.3 x-ray per patients with an average follow-up of 23 months (range 12-34) were collected and evaluated. In all the patients except one, serial radiographs didn't show any progression of radioluciencies lines or periprosthetic osteolysis. Bone density was evaluated by Dual energy X-ray absorptiometry after an average follow-up of 21 months (range 6-46 mo): periprosthetic BMD around the whole stem and the cup increased respectively 2.4% and 7.1%. Treatment was well tolerated and no significant side effects were registered. This retrospective collection of a small group of patients suggest that bisphosphonates should be clinically useful in preventing periprosthetic wear debris mediated osteolysis and claim for dedicated clinical trials.