Femoral head trabecular micro-architecture in patients with osteoporotic hip fractures: Impact of bisphosphonate treatment

Introduction Bisphosphonates are effective in preventing osteoporotic fractures. However, their limited efficacy of bisphosphonates has been suggested as a result of these drugs, which prevent the resorption of bone without improving bone connectivity. The trabecular microarchitecture in patients with osteoporotic hip fractures was evaluated according to their history of bisphosphonate treatment (BT). Methods One hundred thirty-three patients with hip fractures admitted and treated between November 2014 and September 2016. The patients were divided into two groups based on whether they had received treatment with bisphosphonates for > 3 years or not [non-bisphosphonate-treated patients (NT)]. One-to-one propensity score matching generated 15 matched pairs of patients. Microstructural parameters of femoral head were measured by using micro-computed tomography (μCT). Mechanical compression test (Young's modulus, yield strength, and maximum compressive force) was performed following μCT. Results Trabecular bone pattern factor (1.15 ± 0.7 mm^{− 1} versus 1.61 ± 0.5 mm^{− 1}, p = 0.037) and specific bone surface (14.1 ± 0.8 mm^{− 1} versus 15.4 ± 1.9 mm^{− 1}, p = 0.050) were significantly lower in the BT group than in the NT group. Furthermore, Young's modulus was significantly higher in the BT group than in the NT group (72.14 ± 30.75 MPa versus 47.89 ± 29.89 MPa, p = 0.037). In both groups, trabecular bone pattern was the most closely correlated microstructural parameter to bone strength. Microstructural analysis demonstrated that bone connectivity was better preserved in the BT group than in the NT group. Conclusions Bisphosphonate treatment preserves bone mass and bone quality. The factors influencing osteoporotic hip fractures in patients treated with bisphosphonates warrant further research.