Validation of finite element models of the mouse tibia using digital volume correlation

Area of Science:

• Biomechanics
• Biomaterials Science
• Medical Imaging

Background:

• Micro-Finite Element (microFE) models estimate bone mechanical properties from micro-Computed Tomography (microCT) images.
• Experimental validation is crucial for the accuracy of microFE model predictions.
• Digital Volume Correlation (DVC) offers non-invasive, whole-bone displacement measurements.

Purpose of the Study:

• To validate local predictions of microFE models for the mouse tibia using DVC.
• To compare experimental displacements with numerical predictions from microFE models.
• To assess the accuracy of microFE models in predicting bone stiffness and strength.

Main Methods:

• Six mouse tibiae were subjected to stepwise compression within a microCT system.
• MicroCT images were acquired at various load levels (0.5 N to 19.5 N).
• A global DVC algorithm analyzed microCT images to determine displacement fields.
• microFE models were generated and boundary conditions were interpolated from DVC displacements.
• Experimental and numerical displacements were compared at corresponding bone locations.

Main Results:

• microFE model displacement vector magnitudes strongly correlated with DVC measurements (R² > 0.82).
• Longitudinal displacement predictions showed reasonable accuracy, though models tended to overestimate.
• Errors in predicting structural mechanical properties were 14% ± 11% for stiffness and 9% ± 9% for strength.

Conclusions:

• The DVC approach effectively validated microFE models of the mouse tibia.
• microFE models provide reasonable predictions for both local and structural bone properties.
• These validated models are suitable for most preclinical research applications.