Long bone torsion: II. A combined experimental and computational method for determining an effective shear modulus

Area of Science:

• Biomechanics
• Materials Science
• Orthopedics

Background:

• Accurate determination of bone mechanical properties is crucial for understanding skeletal health and disease.
• Existing methods for measuring bone's torsional shear modulus can be destructive or lack precision for whole specimens.

Purpose of the Study:

• To establish a nondestructive technique for determining the effective torsional shear modulus of long bones.
• To validate the technique using canine radii and compare different geometric models for stress prediction.

Main Methods:

• Bonding strain gages to the diaphysis of whole bone specimens.
• Applying pure torsional loads and recording resulting strains.
• Combining experimental strain data with theoretical stress predictions from circular, elliptical, and finite element models.

Main Results:

• Successfully determined the effective torsional shear modulus for four canine radii.
• Demonstrated that the technique is nondestructive to whole bone specimens.
• Averaged heterogeneous shear modulus distribution across the bone's cross-section.

Conclusions:

• The established technique effectively measures the torsional shear modulus of long bones nondestructively.
• The method provides a reliable assessment of bone's shear properties in the circumferential direction.
• This approach offers a valuable tool for biomechanical research and clinical applications.