Bilateral low-energy sequential femoral shaft fractures in patients on long-term bisphosphonate therapy

Objective: The aim of this study was to evaluate the demographic characteristics of patients with bilateral bisphosphonate-related low-energy femoral shaft fractures. Methods: The clinical registry was reviewed for patients with bisphosphonate-related low-energy fractures localized at femoral shaft between January 2008 and January 2012. Patients with a diagnosis of postmenopausal osteoporosis, bisphosphonate usage of at least 5 years and prodromal pain prior to fracture were included the study. Results: Five women met the inclusion criteria. All patients had bilateral low-energy sequential femoral shaft fractures. Fracture patterns were similar and atypical (transverse-short oblique fractures with lateral cortical thickening). Mean period of bisphosphonate treatment was 8.6 years. Mean patient age was 76.2 years. Union time of three patients was between 20 and 28 weeks. The remaining two fractures were revised for delayed union or nonunion. Conclusion: Long-term (over 5 years) use of bisphosphonates may cause insufficiency fractures due to increased fragility and brittleness which have a close relationship with depressed bone remodeling. While there is still no causal relationship between bisphosphonates and atypical, low-energy femoral shaft fractures, we have some concerns about the optimal usage time and long-teem safety of bisphosphonate drugs.