Suspensory apparatus prosthesis in the horse. Part 1: In vitro mechanical properties.

This study compares the effectiveness of different synthetic prostheses by assessing the mechanical properties of equine suspensory apparatus preparations in horses. It found that the mechanical properties of aramid prosthesis with collar augmentation were not significantly different from the suspensory apparatus, unlike the PTFE prosthesis.

Research Methodology

• The researchers conducted single load-to-failure testing on 18 cadaver horse limbs both before and after the replacement of the suspensory apparatus with a synthetic prosthesis.
• Three type of prostheses were examined: PTFE (Polytetrafluoroethylene), aramid, and aramid with collar augmentation.
• These tests resulted in force versus displacement plots which were recorded, along with the characteristics of each failure.

Findings

• It was found that the mean load at failure, energy to failure, and stiffness values of the PTFE prostheses were lower than those of the suspensory apparatus and aramid prosthesis.
• Furthermore, the PTFE prostheses predominantly failed either by elongating excessively or by rupturing altogether.
• Conversely, the mechanical properties of the aramid prosthesis with collar augmentation were not significantly different from the natural suspensory apparatus.
• The main failure point for both types of the aramid prostheses was at the point where they were fastened to the bone with screws.

Interpretation

• The aramid prosthesis with collar augmentation is a promising substitute for the suspensory apparatus in horses, as it mirrors the apparatus’ mechanical properties, suggesting it may provide comparable support and resist forces similarly.
• However, the point of screw fixation to bone needs improvement to prevent failures.
• On the other hand, PTFE prostheses were found to be insufficient, with overall inferior mechanical properties and failure modes. Therefore, it may not be suitable for use as a suspensory apparatus substitute.