Incomplete atypical femoral fractures after bisphosphonate use in postmenopausal women.

Purpose: This study aimed to determine the prevalence of incomplete atypical femoral fractures (iAFFs) in postmenopausal women using bisphosphonates and to investigate the potential risk factors for the development of iAFF.

Methods: The national health-care records system indicated that 2746 postmenopausal women in our region aged ≥50 years were taking bisphosphonates. Using an assumed iAFF prevalence of 10% and levels of 5% significance and ±5% precision, we calculated that a sample size of 132 participants was needed for this study.