Table 1.

Atypical femoral fracture: major and minor features.

Major features
The Fracture is associated with minimal or no trauma, as in a fall from a standing height or less The fracture line originates at the lateral cortex and is substantially transverse in its orientation, although it may become oblique as it progresses medially across the femur Complete fractures extend through both cortices and may be associated with a medial spike; incomplete fractures involve only the lateral cortex. The fracture is non-comminuted or minimally comminuted Localized periosteal or endosteal thickening of the lateral cortex is present at the fracture site (“beaking” or “flaring”)
Minor features
Generalized increase in cortical thickness of the femoral diaphysis Unilateral or bilateral prodromal symptoms such as dull or aching pain in the groin or thigh Bilateral incomplete or complete femoral diaphysis fractures Delayed fracture healing Comorbid conditions (e.g., vitamin D deficiency, rheumatoid arthritis, hypophosphatemia) Use of pharmaceutical agents (e.g., bisphosphonates, glucocorticoids, proton pump inhibitors)