Presentations

Although bone mineral densitometry has been well established in human clinical practice for decades as a diagnostic method to determine increased fracture risk, there is a lack of application in the veterinary field. The techniques may have a place in assessing fracture risk of certain equine bones, however current work is in the experimental research stage and has yet to achieve widespread clinical use. The aim of this in vitro study was to investigate the correlation between breaking force, bone mineral density and computer tomographic cross-sectional dimensions including diameter, cortical area and the cortical width of each metacarpal bone quadrant. We hypothesized that there is a siginifcant positive correlation between bone mineral density, CT morphometric parameters and the bending strength and breaking force of equine metacarpal bone.

Metacarpal bones were extracted from 13 horses that were euthanized for reasons unrelated to musculoskeletal conditions. The study involved the assessment of the bone mineral density across several regions of interest (ROIs) using dual-energy X-ray absorptiometry (DXA). The bones were then scanned using a computed tomography (CT) scanner, in order to measure cross-sectional morphometric properties. Their mechanical properties were then determined by a 3-point bending test.

We have found significant positive linear correlations between the breaking force and the mineral densities of the entire metacarpal bone (P < 0.001, r = 0.72), the medial cortex (P < 0.001, r = 0.68) and the transverse ROI (P < 0.001, r = 0.61). The bone diameter was also found to significantly correlate with bending strength (P < 0.001, r = 0.77) and Young’s modulus (P < 0.001, r = 0.68). The cortical widths of each bone quadrant and the overall cortical area were not proven to correlate to any of the measured mechanical parameters in this study.

Since bone mineral density was shown to be a significant indicator of breaking force, these measurement techniques can be the subject of wider scale in vivo research, in order to assess their potential value of predicting fracture risk in equine metacarpal bones.