Long-term bisphosphonate use and femoral morphological changes in osteoporosis patients: a retrospective cohort study

We examined the association between long-term bisphosphonates use and morphological change in the femur.

140 patients (97.1% female, 70.8 ± 8.7 years) with over 5-year BP use (8.1 ± 2.4 years) were matched 1:1 for age (± 3), same BMD status with patients as a control group. The primary outcome was femoral lateral bowing (FLB). The hip-knee-shaft angle (HKSA) and femoral neck shaft angle (FNSA) were secondary outcomes.

Compared with the Control group, the femoral lateral bowing and hip-knee-shaft angle (5.9 ± 4.3° vs. 3.7 ± 1.7°; 6.6 ± 2.6° vs. 5.1 ± 1.5°, respectively) were significantly larger, while the femoral neck shaft angle was significantly lower (128.1 ± 3.4° vs. 129.3 ± 2.5°) in the BP group. The correlation analysis shows there is a positive correlation between the BP therapy time and FLB (r = 0.2566, P < 0.01), HKSA (r = 0.1353, P = 0.1325), while negative correlation between the BP therapy time and FNSA (r = - 0.1637, P = 0.0681) without significance, indicating that the longer BP therapy, the larger the lateral bowing of the femur.

Patients who took bisphosphonates over 5 years have a larger femoral lateral bowing, hip-knee-shaft angle and a smaller femoral neck shaft angle than control patients.