Comparison of Mechanical Stimuli for Trabecular-bone Adaptation: In Silico Prediction Framework

Trabecular-bone adaptation (TBA) is a continuous process, adjusting bone morphology against external loading and driven by mechanical stimuli. Various stimulus types such as strain energy density (SED) and stress magnitude were extensively studied. However, the in silico quantification and comparison of local trabeculae morphology caused by different mechanical stimuli, especially the parts of decomposed SED remains underexplored. This study introduces a 3D finite-element (FE) model to simulate mechanically driven TBA, with the aim to quantify the results of TBA models with different mechanical stimuli. Utilizing FE software ABAQUS with user-defined subroutines, the models simulate the trabeculae evolution under mechanical load. The outcome for the total SED, deviatoric SED and von Mises stress are compared, quantified with morphometric parameters of TB structure. The results show that the total first stimulus with equally weighted hydrostatic and deviatoric components demonstrates a higher resorption tendency compared to the deviatoric SED. This could be explained by its higher - quadratic - dependence on effective stress, while the results for the models based on von Mises stress are related to this stress linearly. This work advances the understanding of contribution of different mechanical stimuli to the TBA process at single-trabeculae level, offering insights into the trigger mechanism of trabecular-bone adaptation.