Atypical femoral fracture in a bisphosphonate-naïve patient on denosumab for osteoporosis.

A post-menopausal Caucasian woman sustained an atypical femoral fracture (AFF) after 5-years continuous denosumab for osteoporosis without prior bisphosphonate exposure. This is only the fifth case reported of AFF in a bisphosphonate-naïve patient receiving denosumab for osteoporosis. Although rare, physicians should consider AFF in patients taking denosumab even without prior bisphosphonate exposure.

introductionDenosumab has demonstrated overwhelmingly favourable skeletal benefit/risk profile in managing post-menopausal osteoporosis with up to 10-year exposure in the extension of the pivotal FREEDOM randomised placebo-controlled trial. Four previous cases of atypical femoral fracture have been reported in bisphosphonate-naïve patients receiving denosumab for osteoporosis.

methodsWe present an 85-year-old Caucasian post-menopausal woman without prior fragility fracture who sustained unilateral atypical femoral fracture after 5-years continuous subcutaneous denosumab for osteoporosis. She had no prior bisphosphonate or glucocorticoid exposure and had known chronic kidney disease.

resultsX-ray scan demonstrated complete, non-comminuted left proximal femoral shaft fracture meeting radiographic criteria for an atypical femoral fracture. Computed tomography (CT) scan lower limbs revealed unusual side-by-side appearance of proximal and distal fragments of left proximal femur. DXA BMD was artefactually elevated at lumbar spine (1.504 g/cm

conclusionThe patient underwent intramedullary nailing of the femur and denosumab was ceased. This is only the fifth case reported of atypical femoral fracture in a bisphosphonate-naïve patient receiving denosumab for osteoporosis. Although rare, physicians should maintain a high index of suspicion for atypical femoral fracture in a patient taking denosumab even without prior bisphosphonate exposure.