Denosumab-associated Periprosthetic Atypical Femur Fracture: A Case Report

INTRODUCTION: Denosumab is generally used for 5–10 years to treat postmenopausal osteoporosis. Although atypical fractures caused by bisphosphonate use are well known, reports of denosumab-associated femur fractures are rare. CASE REPORT: Herein, a 75-year-old woman suffered an atypical periprosthetic femoral fracture 31 months after receiving denosumab. The fracture occurred transverse to the stem tip with lateral cortical thickening. The patient underwent revision surgery for conversion to a longer cemented stem. The fracture site healed 10 months after revision surgery. CONCLUSION: As far as we know, there have been no reports of a case on periprosthetic atypical femur fracture associated with denosumab. Our study shows the potential of periprosthetic atypical femoral fractures in patients using denosumab for a long time.