Separating effects of bone-quality changes at multiple scales in steroid-induced osteoporosis: Combining multiscale experimental and modelling approaches

Metabolic bone diseases have an impact on the multi-scale structure of bone and its mechanical properties. This study aims to conduct quantitative analysis of the link between specific material-level changes and mechanical alterations of bone tissue. We combine several scanning probe methods with an analytical multiscale model to investigate these links in a mouse model (Crh^−120∕+) with endogenous steroid production. Experimental results from our prior study are used, which showed significant changes in spatial maps of nano-scale orientation, mineralization, and microporosity in Crh^−120∕+ mice bone. An analytical composite/continuum mechanical model is incorporated with these experimental parameters to predict the progressive reduction in elastic moduli. The largest fractional reduction in elastic modulus is found to arise from incorporation of microscale porosity, followed by the reduced nanoscale degree of orientation. Our work provides both insights into the altered structure-performance relations and a systematic analytical framework for linking scanning micro- and nanoprobe experimental data on hierarchical structural materials to macroscopic biomechanical outcomes.