The relationship between trabecular bone structure modeling methods and the elastic modulus as calculated by FEM

Area of Science:

• Orthopedics
• Biomedical Engineering
• Materials Science

Background:

• Trabecular bone's mechanical properties are crucial for hip arthroplasty outcomes.
• Osteoporosis and coxarthrosis significantly alter bone architecture.
• Accurate finite element analysis (FEA) requires high-resolution imaging data.

Purpose of the Study:

• To investigate the impact of varying scan resolution (voxel size) on the elastic properties of trabecular bone.
• To determine the relationship between voxel size and apparent modulus derived from FEA.
• To identify a threshold voxel size for reliable FEA calculations in hip bone specimens.

Main Methods:

• Trabecular bone cores from 42 hip arthroplasty patients were analyzed.
• Microcomputed tomography (microCT) was used to scan specimens at 36-micron resolution.
• Image stacks were converted to finite element models, and apparent modulus was calculated under varying voxel sizes (72 to 1080 microns).

Main Results:

• Increasing voxel size led to a decrease in the FEA-derived apparent modulus.
• A correlation was observed between the slope of the voxel size versus modulus relationship and trabecular bone architectural indices.
• A critical voxel size threshold was identified beyond which modulus values became unreliable.

Conclusions:

• Scan resolution critically influences the accuracy of FEA-derived elastic properties of trabecular bone.
• Higher resolution (smaller voxel size) is necessary for precise mechanical property calculations.
• The findings have implications for optimizing microCT scanning protocols and FEA in orthopedic research.