Stiff and strong compressive properties are associated with brittle post-yield behavior in equine compact bone...

Area of Science:

• Biomechanics
• Materials Science
• Veterinary Medicine

Background:

• The post-yield mechanical behavior of compact bone is crucial for understanding bone's response to injury.
• Factors influencing this behavior, such as density and remodeling, are not fully understood.
• The third metacarpal bone in horses provides a relevant model for studying large animal bone mechanics.

Purpose of the Study:

• To investigate the correlation between post-yield mechanical properties of equine compact bone and its material characteristics.
• To determine the relationship between bone density, elastic modulus, strength, remodeling, and post-failure morphology.

Main Methods:

• Single-load compression-to-failure tests were performed on equine third metacarpal bone specimens.
• Post-yield stress, strain, and absorbed energy were measured.
• These properties were compared with elastic modulus, yield stress, ash density, macroscopic appearance, and histologic remodeling.

Main Results:

• Higher elastic modulus, yield stress, and ash density were associated with lower post-yield mechanical properties.
• Specimens with fractures showed lower post-yield properties, while those without fractures had higher properties.
• Microscopic remodeling was linked to higher post-yield properties, but not gross morphology.

Conclusions:

• Bone material density and stiffness are inversely related to post-yield mechanical behavior.
• Fracture morphology and remodeling activity significantly influence post-yield bone mechanics.
• An abrupt decrease in post-yield properties at intermediate ash density suggests a functional limit for bone stiffness and strength.