Nonlinear micro finite element models based on digital volume correlation measurements predict early microdamage in...

Area of Science:

• Biomaterials Science
• Biomechanics
• Regenerative Medicine

Background:

• Critical-sized bone defects pose significant clinical challenges.
• Biomaterials and bone morphogenetic proteins (BMPs) show promise for bone regeneration.
• Optimizing spatial-temporal BMP release is crucial for restoring native bone properties.

Purpose of the Study:

• To validate nonlinear micro finite element (μFE) models using experimental data for predicting biomechanical strength and microdamage in newly formed bone.
• To assess the impact of tissue heterogeneity on model predictions.

Main Methods:

• Experimental compression of newly formed bone using in situ X-ray computed tomography.
• Measurement of local displacements via digital volume correlation (DVC).
• Validation of linear and nonlinear μFE models against DVC data.

Main Results:

• Linear μFE models showed high correlation with DVC displacements; tissue heterogeneity had minimal effect.
• Nonlinear μFE models improved correlation and revealed microdamage onset at low apparent strains.
• Microdamage occurred near cavities or thin trabeculae, independent of mineralization, with slightly increased accumulation when including heterogeneity.

Conclusions:

• Nonlinear μFE models effectively capture local microdamage in regenerating bone.
• These models can enhance understanding of bone healing and mechanical competence.
• Improved models will aid the development of advanced BMP delivery systems for bone regeneration.