EVALUATION OF BONE BIOMECHANICAL PROPERTIES IN DIFFERENT REGIONS OF THE EQUINE THIRD METACARPUS

Purpose: To compare biomechanical characteristics at different regions of the equine third metacarpal bone using standardized test specimens. Methods: Standardized test specimens were made from samples collected from each third metacarpal bone. Cortical bone samples were collected from the lateral (ts4L) and medial (ts4M) cortices of the mid-diaphysis and trabecular bone samples were collected from the distal (ts3) and proximal (ts2) epiphyses. A sample corresponding to the mid third of the third metacarpal bone was also collected (ts1). Test specimens were submitted to compressive testing for determination and comparison of biomechanical properties. Results: Stress and modulus of elasticity of ts4L and ts4M did not differ at the time of fracture. However, the modulus of elasticity of ts4L and ts4M differed from ts1. Maximum tension and modulus of elasticity differed between ts2 and ts3. A medium to high positive correlation between test specimen density and bone biomechanical properties was observed. Conclusion: The lateral and medial cortices of the equine third metacarpal bone have similar biomechanical characteristics. The proximal and distal epiphyses of the equine third metacarpal bone have different biomechanical properties that are correlated with bone density in these regions.