Duration‐Dependent Increase of Human Bone Matrix Mineralization in Long‐Term Bisphosphonate Users with Atypical Femur Fracture

Bisphosphonates (BPs) are the most widely used drugs for treatment of osteoporosis but prolonged use BPs might increase risk atypical femur fracture (AFF). There only a few studies that address bone material quality in patients on long-term BP with or without AFFs. We analyzed 52 trans-iliac biopsies from therapy (n = 26) and AFF. At microscopic level, degree mineralization (DMB) was assessed whole by X-ray digitized microradiography while microhardness Vickers microindentation, matrix characteristics Fourier transform infrared microspectroscopy (FTIRM) (mineral/organic ratio, mineral maturity crystallinity, collagen maturity) were measured at random focal areas. The AFF treated longer than non-AFF (9.7 ± 3.3 years versus 7.9 2.7 years). As expected, remodeling low both groups, difference between them. group had significantly higher DMB cortical (+2.9%, p .001), which remained so after adjusting duration (p .007), showed trend cancellous (+1.6%, .05). Consistent DMB, heterogeneity index (HI) lower group, illustrating group. A significant positive correlation found AFF, not Microhardness similar groups. conclude duration-dependent leading to non-AFF. Because have high affinity lining walls osteocyte lacunae, accumulation matrix-bound could lead inhibition cytoskeleton blunting their response mechanical strains, hypothesis be further investigated. © 2021 American Society Bone Mineral Research (ASBMR).