Asian Ethnicity and Femoral Geometry in Atypical Femur Fractures: Independent or Interdependent Risk Factors?

Area of Science:

• Orthopedics
• Bone Metabolism
• Pharmacogenomics

Background:

• Atypical femur fractures (AFF) show higher incidence in Asian populations.
• Mechanisms linking Asian ethnicity to AFF risk, including femoral geometry and bisphosphonate response, require clarification.

Purpose of the Study:

• To investigate the independent contributions of Asian ethnicity, proximal femoral geometry, and bisphosphonate use to AFF status.
• To determine if ethno-specific femoral geometry explains the increased AFF risk in Asian patients.

Main Methods:

• Retrospective cohort study of 163 female patients with AFFs or typical femur fractures (TFF).
• Analysis included Asian ethnicity, proximal femoral geometry (Sydney AFF Score components), and bisphosphonate use.
• Multiple logistic regression models were used to assess predictors of AFF status.

Main Results:

• Asian subjects comprised a fourfold higher proportion in the AFF group compared to the TFF group.
• Asian ethnicity was a robust independent predictor of AFF, increasing odds sevenfold (p=0.001), independent of femoral geometry.
• Asian subjects exhibited higher bisphosphonate use and lower AFF scores among bisphosphonate users.

Conclusions:

• Asian ethnicity is a strong, independent risk factor for AFF, not explained by femoral geometry.
• Bisphosphonate use may be associated with a greater predisposition to AFF in Asian individuals compared to non-Asians.