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

This research explores the characteristics of equine compact bone, suggesting that the mechanical properties of the bone after it yields (or begins to deform under stress) are influenced by factors such as bone density, elasticity, strength, evidence of remodeling, and the appearance of the bone after failure.

Objective of the research

• The main objective of the research was to test the hypothesis that the post-yield behavior of compact bone material in horses is impacted by several variables including material density, elasticity, strength, evidence of remodeling and the physical appearance of the specimen after failure.

Methodology

• To test the hypothesis, the researchers examined the post-yield behavior of compact bone material from the third metacarpal bone of 10 horses that ages varied from 5 months to 20 years.
• They investigated these bones using a “single-load compression-to-failure” method.
• The data points, including stress, strain, and absorbed energy, were then compared with elements like the compressive elastic modulus, ash density, yield stress and post-failure appearance of the specimen.

Findings

• Results showed that bones with high values of elastic modulus, yield stress, and ash density demonstrated poor post-yield mechanical properties, indicating brittle failure.
• Bones that displayed fractures had poor post-yield properties, while bones that didn’t show evidence of fractures had better post-yield properties. This suggests that the physical appearance of bone post-failure is a significant predictor.
• At the microscopic level, evidence of remodeling activity (i.e., how the bone repaired itself over time) was found to be linked to superior post-yield mechanical properties. Microscopic remodeling activity, however, didn’t seem to correlate with the bone’s appearance after failure.
• An important observation was the abrupt shift from high to very low values of post-yield mechanical properties at intermediate levels of ash density. This could potentially serve as a limit for the overall stiffness and strength of bone material.

Implications and conclusions

• The research suggests that several factors including density, elasticity, and remodeling activity play an important role in determining the post-yield mechanical properties of equine compact bone.
• Understanding these qualities could improve our knowledge about bone resistance and strength, potentially aiding in the prevention and treatment of bone injuries and diseases, not just in horses, but in other animals as well.