Epidemiology, Pathophysiology and Management of Atypical Femur Fractures: an Update

To summarise recent publications addressing the epidemiology, pathogenesis and management of atypical femur fractures (AFFs).

AFFs have been reported in anti-resorptive treated individuals, bisphosphonate-naïve individuals and individuals with monogenic bone diseases. The likelihood of developing an AFF increases with prolonged exposure to anti-resorptive treatment. AFF risk declines following anti-resorptive discontinuation. Asian ethnicity has emerged as an important risk factor for AFF. Although excluded from the current ASBMR AFF case definition, periprosthetic AFFs and atypical fractures at non-classical sites have been increasingly reported. Following an AFF, anti-resorptive therapy should be discontinued, surgical treatment with intramedullary nailing considered, the contralateral femur imaged, and the underlying osteoporosis addressed. Emerging evidence suggests teriparatide may aid healing in surgically managed AFFs but not in conservatively managed incomplete AFFs. AFFs remain a rare side effect of anti-resorptive treatment. Emerging areas of interest and further research include genetic and ethnic risk factors and advancements in diagnostic technologies for AFFs.