LAUSR

Micro-CT based finite element models (FEM) are efficient tools to assess bone mechanical properties. Although they have been developed for different animal models, there is still a lack of data for growing rat long bone models. This study aimed at developing and calibrating voxel-based FEM using micro-CT scans and experimental data. Twenty-four tibiae were extracted from rats aged 28, 56 and 84 days old (d.o.)(n=8/group) and their stiffness' were evaluated using three-points bending tests. Prior to testing, tibiae were scanned, reconstructed and converted into FEM composed of heterogeneous bone properties based on pixel grayscales. Three element material laws (one per group) were calibrated using back-calculation process based on experimental bending data. Two additional specimens per group were used for model verification. Obtained correlations between experimental and FEM stiffness' were 0.43, 0.10 and 0.66 with RMSE of 14.4%, 17.4% and 15.2% for 28, 56 and 84 d.o. groups, respectively. Relationships between bone physical and mechanical properties were found to change during the growth, similarly to bending stiffness', which increased with bone development. The reduced correlation observed for the 56 d.o. group may be related to the pubescent transition at that age group. These FE models will be useful for investigation of bone behavior in growing rats.