A new multiscale micromechanical model of vertebral trabecular bones

Area of Science:

• Biomechanics
• Materials Science
• Computational Modeling

Background:

• Vertebral trabecular bone (VTB) has a complex, highly porous microstructure.
• Accurate prediction of VTB mechanical properties is crucial for understanding bone health and disease.
• Existing models may not fully capture the multiscale nature of VTB anisotropy.

Purpose of the Study:

• To develop and validate a novel three-dimensional (3D) multiscale micromechanical model for predicting VTB linear anisotropic mechanical properties.
• To establish a hierarchical analysis framework integrating different micromechanical methods across multiple length scales.
• To investigate the influence of age and sex on VTB mechanical properties.

Main Methods:

• A nested 3D modeling analysis framework was employed, combining the 3D parametric high-fidelity generalized method of cells (HFGMC) and the 3D sublaminate model.
• At the nanoscale, 3D HFGMC was used for the mineral collagen fibrils composite representative unit cell (RUC).
• At the submicron scale, the 3D sublaminate model analyzed lamellar stacks representing trabeculae.
• At the micron scale, 3D HFGMC was applied to VTB-RUC geometries derived from microcomputed tomography scans.

Main Results:

• The model successfully predicted the overall linear anisotropic mechanical properties of VTB microstructures.
• Effective elastic properties were derived at nanoscale (fibrils), submicron scale (lamellae), and micron scale (VTB-RUC).
• Predicted longitudinal Young's modulus showed good agreement with reported literature values for single trabeculae and VTB-RUCs.
• The study examined the impact of age and sex on predicted VTB elastic properties.

Conclusions:

• The proposed 3D nested modeling analysis framework is effective for predicting the mechanical properties of vertebral trabecular bone.
• The multiscale approach accurately captures the anisotropic behavior of VTB.
• The model provides a valuable tool for further research into VTB biomechanics and age-related changes.