Case report of spontaneous, nonspinal fractures in a multiple myeloma patient on long-term pamidronate and zoledronic acid.

Pamidronate and zoledronic acid are two potent intravenous bisphosphonates used in the treatment of multiple myeloma as well as osteoporosis. While the concern for heightened fracture risk in a patient on long-term bisphosphonate treatment for malignancy has been previously noted, we present the first case of spontaneous, nonspinal fractures in a patient undergoing treatment for multiple myeloma. The patient had a positive 9-year history of bisphosphonate treatment and presented with sequential subtrochanteric stress fractures of the left and right femurs. Pathological reports of fracture site biopsies demonstrate signs consistent with ametabolic bone and no malignancy. These findings point to extreme inhibition of bone turnover by bisphosphonates as the cause of this patient's morbidity. This is a single retrospective case study (level IV evidence).