Atypical fractures of the femur: an updated overview from the laboratory to the operating room

Atypical femoral fractures (AFF) are peculiar stress or insufficiency fractures typically occurring in patients with a prolonged period of bone turnover alterations, mostly associated to specific risk factors, comorbidities, or drug therapies. AFF are typically subthrocanteric or diaphysial fractures, with a transverse or poorly oblique fracture rim, not comminuted, and generally not correlated to a clear traumatic mechanism. Their incidence is low compared to standard fractures, but they are challenging clinical issues to deal with. The treatment of AFF is based on the diagnosis: in case of an AFF, surgery is needed, but it is associated to a very slow healing and to frequent complications. If AFF are early diagnosed (before the fracture completes or as an impending fracture pattern), a conservative treatment based on the interruption of bone turnover modifying drugs, protected weightbearing, administration of bone stimulating agents, and the study of similar conditions in the contralateral femur is suggested. Surgical treatment includes intramedullary nailing or plating even if the former is suggested for its superior mechanical advantages with respect to the latter. The Authors present an update of the state of the art on this topic that is rare but still now challenging.