Abstract
Atypical femoral fracture (AFF) is defined as an atraumatic or low stress fracture located between the subtrochanteric and supracondylar area of the femur, with typical clinical and radiological features. These factures are most often considered a complication of long-term treatment using bisphosphonates and denosumab, also occurring more often during treatment using glucocorticoids and proton-pump inhibitors.
Determination of an atypical femoral fracture continues to be governed by the revised criteria of the ASBMR (American Society of Bone and Mineral Research) published in 2014. Assessment of the specificity of individual radiological criteria has shown that the transversal orientation of the fracture of the lateral cortex is crucial.
Subsequent progress of the fracture line should be transversal or oblique. At our facility we have also documented the case of a female patient with a spiral fracture, which met ASBMR criteria for an atypical femoral fracture.
ASBMR criteria for AFF exclude periprosthetic fractures, despite orthopaedic facilities pointing out the existence of periprosthetic fractures, which have the characteristics of would meet radiological criteria for atypical femoral fracture and also occur more frequently in patients taking bisphosphonates. The prevalence of these types of fractures among periprosthetic fractures ranges between 8-10 %.
The risk of these atypical periprosthetic fractures increases as the duration of use of bisphosphonates increases. The possibility of genetic predisposition for origin of atypical femoral fractures can be considered in persons who have not taken any risk medication of such fractures.
The cause may also be genetically dependent bone disorders, which are accompanied by pseudofractures very similar to atypical fractures. This article also discuses other accessory risk factors of AFF and recommendations for therapy.