Atypical femoral neck fracture

Atypical femoral fractures are usually observed in the proximal one third of the femoral shaft (although it can occur anywhere along the femoral diaphysis from just distal to the lesser trochanter to proximal to the supracondylar flare of the distal femoral metaphysis) (1).

These atypical femoral fractures

• may be bilateral
• healing may be delayed
• may be associated with a variety of comorbid conditions and the use of pharmaceutical agents

The fracture usually occurs after minimal (fall from a standing height or less) or no trauma and may be:

• complete - generally they are transverse fractures (although they may have a short oblique configuration) and not comminuted
• incomplete - manifested by a transverse radiolucent line in the lateral cortex

Reference:

1. Shane E et al. Atypical subtrochanteric and diaphyseal femoral fractures: report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res. 2010;25(11):2267-94