Arthrodesis of the equine proximal interphalangeal joint: a biomechanical comparison of 3-hole 4.5 mm locking compression plate and 3-hole 4.5 mm narrow dynamic compression plate, with two transarticular 5.5 mm cortex screws.

The research investigated the comparison of biomechanical characteristics between two techniques used for equine proximal interphalangeal joint arthrodesis. It concluded that fixation of this joint with a 3-hole 4.5mm locking compression plate is equivalent in biomechanical terms to fixation with a 3-hole 4.5mm narrow dynamic compression plate under the tested conditions.

Study Methodology

• The study was conducted using pairs of cadaveric adult equine forelimbs. Each pair had one limb randomly assigned to either a locking compression plate (LCP) or a dynamic compression plate (DCP), while the other limb in the pair was assigned to the other group by default.
• Both plates used were 3-hole 4.5mm, supplemented by two transarticular 5.5mm cortex screws.
• Biomechanical parameters such as construct stiffness, gap formation across the joint, and rotation around the joint were analyzed at multiple stages of the testing process.
• These parameters were checked before and after each cycle of axial loading. The loading regimen contained four cycles, each involving 5000 loading instances.
• After these cycles, which total 20,000 axial loadings, each construct was pushed to the point of failure.

Results

• The collected data revealed no significant differences in the biomechanical variables, i.e., construct stiffness, gap formation or sagittal plane rotation, between the two techniques at any measured point.
• The results showed that the locking compression plate and the dynamic compression plate performed similarly under the study’s specific conditions.

Conclusion

• From a biomechanical perspective, the 3-hole 4.5mm LCP was just as effective in the equine proximal interphalangeal joint arthrodesis as the 3-hole 4.5mm narrow DCP, as per the specific test conditions of this research.
• This result could have implications for equine surgery and could potentially lead to a broader selection of viable techniques for this type of procedure.