Atypical femoral fracture in a metastatic bone disease patient six months after discontinuation of denosumab received sequentially to previous bisphosphonate therapy - A case report.

Although, both bisphosphonates and denosumab are effective in reducing the risk of skeletal-related events in patients with metastatic bone disease, many concerns were being raised about the possible association between their use and atypical femoral fractures. A case of an atypical femoral fracture in a metastatic bone disease patient, six months after discontinuation of long-term zoledronic acid therapy and sequential treatment with denosumab is reported. After extensive laboratory and imaging examination, the fracture was classified as atypical and it was finally treated with discontinuation of denosumab, long cephalomedullary interlocking nailing and vitamin D administration. Sequential treatment with bisphosphonates and denosumab in patients with metastatic bone disease, may lead to an overlapping treatment effect, increasing bone suppression and the risk of atypical femoral fracture. In addition, discontinuation of denosumab may activate bone remodeling units in an area with microdamage accumulation in cortical bone caused by the previous bone suppression from the antiresorptive treatment. The activation of bone remodeling units may accelerate the occurrence of the atypical femoral fractures.

Atypical Femoral Fracture in a Patient without Bisphosphonate or Denosumab Exposure-A Case Report.

Introduction: Atypical femoral fractures (AFF) are associated with the use of bisphosphonates (BPs) or denosumab. However, few cases that meet the characteristics of these fractures, as established by the American Society of Bone and Mineral Research, have occurred in patients who have never used antiresorptive drugs. Case Report: We report a case of AFF in a 67-year-old woman who had never used antiresorptive medications. The history and comorbidities of the patient, the characteristics of the fracture, and the subsequent treatment are presented. Conclusion: AFFs may occur even in patients who have never been exposed to BPs or denosumab. The absence of antiresorptive osteoporosis therapy and the lack of radiographic focal periosteal reaction in the lateral femoral cortex, as in our case, can make it difficult to detect and prevent the disorder. Prolonged use of proton pump inhibitors and Vitamin D deficiency-related osteomalacia may contribute to the occurrence of these fractures. Further studies are required to accurately understand all inciting factors contributing to the development of AFFs.