Atypical femur fracture in two patients treated with denosumab: case reports of a patient undergoing maintenance hemodialysis and a kidney transplant recipient, with a literature review of the denosumab used to treat these patients

Abstract

Background Osteoporosis is a serious complication for both patients undergoing maintenance hemodialysis (MHD) and kidney transplant (KTx) recipients. Denosumab (Dmab) is a highly efficacious drug used to treat osteoporosis. However, like bisphosphonates, Dmab has the rare complication of atypical femur fracture (AFF). Here, we report two cases of AFF in a patient on MHD and a KTx recipient during treatment with Dmab. Case presentation Case 1 was a 78-year-old female patient undergoing MHD diagnosed with an AFF in April 2023. In 2018, she started hemodialysis necessitated by glomerulonephritis caused by parvovirus B19. She had been receiving intravenous alendronate for osteoporosis since 2005, then changed to subcutaneous Dmab in 2020. She underwent an intramedullary nail osteosynthesis for her AFF and is doing well on teriparatide. Case 2 was a 67-year-old female KTx recipient diagnosed with an AFF in June 2023. She had been on oral minodronate since 2014 but was switched to subcutaneous Dmab in 2020 owing to repeated fractures. She is doing well on romosozumab after intramedullary nail osteosynthesis. Conclusions We report two cases of AFF treated with Dmab. Case 1 was a patient undergoing MHD and case 2 was a KTx recipient. AFFs are relatively rare and, to our knowledge, have not been reported in patients undergoing MHD or KTx recipients. Dmab-associated AFFs are likely to increase in the future as the population ages, and adequate attention should be paid to patients undergoing MHD and KTx recipients.