A Novel 3D Microstructural Model for Trabecular Bone: II. The Relationship Between Fabric and the Yield Surface

Area of Science:

• Biomechanics
• Materials Science
• Orthopedics

Background:

• Understanding the mechanical behavior of human trabecular bone is crucial for predicting bone failure and designing orthopedic interventions.
• Previous studies have focused on elastic properties, but the yield behavior, which governs damage initiation, remains less understood.
• Trabecular bone's complex microstructure, characterized by volume fraction and anisotropy, significantly influences its mechanical response.

Purpose of the Study:

• To utilize a novel 3D microstructural model to determine the yield surface of human trabecular bone.
• To investigate the influence of volume fraction and degree of anisotropy on the bone's yield behavior.
• To establish relationships between microstructural parameters and continuum-level mechanical damage initiation.

Main Methods:

• Development and validation of a novel 3D microstructural model for trabecular bone.
• Finite element analysis (FEA) of open and closed cell geometries under various loading conditions with periodic boundary conditions.
• Calculation of effective yield stresses using a 0.2% offset method and fitting to an orthotropic Hill criterion.

Main Results:

• Distinct and strong relationships were identified between volume fraction, fabric (anisotropy), and the calculated yield surface parameters.
• These relationships were consistent for both open and closed cell trabecular bone geometries.
• The post-yield behavior of trabecular tissue was approximated using data from cortical bone.

Conclusions:

• Volume fraction and fabric are key predictors of the yield surface in human trabecular bone.
• The developed model successfully relates microstructural features to continuum-level mechanical properties.
• These findings provide a basis for predicting the initiation of mechanical damage in trabecular bone.