Several recent papers have reported atypical femoral subtrochanteric or dyaphyseal insufficiency fractures associated with long-term bisphosphonate use. There still has been the debate on the relationship between bisphosphonates and atypical fractures. Furthermore, the pathogenesis of the atypical femoral fractures is not fully elucidated. Here, we intended to look into the atypical femoral subtrochanteric or dyaphyseal fracture through the literature search and also discuss the natural course of the femoral insufficiency fracture. We found that atypical femoral fractures have somewhat a relation with bisphosphonates despite rare occurrence. We also found that atypical cortical reactions or incomplete atypical fractures are ultimately apt to fracture completely. Conclusively it is better to perform prophylactic stabilization in the atypical femoral subtrochanteric or dyaphyseal fractures if pain, the longer duration of bisphosphonate use, or the cortical thickening on outer cortex is present. [Korean Journal of Bone Metabolism, 17(2): 55-62, 2010]
