The relationship between estimated bone strength by finite element analysis at the peripheral skeleton to areal BMD and trabecular bone score at lumbar spine

Bone strength, estimated by finite element (FE) analysis based on high resolution peripheral quantitative computed tomography (HR-pQCT) images is an important contributor to understanding risk of fracture. However, it is a peripheral device and cannot be evaluated in vivo at lumbar spine L1-L4. The aim of this study was to investigate if the axial bone quality can be predicted by strength measurements of peripheral bone. Peripheral bone microarchitecture, areal bone mineral density (aBMD) and trabecular bone score (TBS) were measured in adults individuals (n = 262, 60 years and older; 63% women). Stiffness and failure load were estimated by FE analysis at HR-pQCT images at radius and tibia. Areal BMD and TBS were measured by dual energy X-ray absorptiometry (DXA) at L1-L4. Correlations between peripheral and axial data were estimated for each gender adjusted by age, weight, and height. Areal BMD L1-L4 resulted in weak to moderate significant correlations with stiffness and failure load at radius (women: R-2 = 0.178, p < 0.05 and R-2 = 0.187, p < 0.001, respectively; men: R-2 = 0.454 and R-2 = 0.451, p < 0.001, respectively) and at tibia (women: R-2 = 0.211 and R-2 = 0.216, p < 0.001, respectively; men: R-2 = 0.488 and R-2 = 0.502, p < 0.001, respectively). TBS showed a very weak or no correlation with stiffness and failure load at radius (women: R-2 = 0.148 and R-2 = 0.150, p < 0.05, respectively; men: R-2 = 0.108 and R-2 = 0.106, p < 0.05, respectively) and at tibia (women: R-2 = 0.146 and R-2 = 0.150, p < 0.05, respectively; men: R-2 = 0.072 and R-2 = 0.078, respectively). These data suggest that aBMD L1-L4 was better explained by peripheral bone strength characteristics than the TBS, mainly in men and tibia is generally the site with a better relationship.