An in vitro biomechanical comparison of equine proximal interphalangeal joint arthrodesis techniques: an axial positioned dynamic compression plate and two abaxial transarticular cortical screws inserted in lag fashion versus three parallel transarticular cortical screws inserted in lag fashion.

This study focuses on comparing biomechanical properties of two surgical methods used for equine proximal interphalangeal (PIP) joint arthrodesis. The results reveal that a dynamic compression plate with 2 abaxial transarticular cortical screws (DCP-TLS) is more capable of withstanding static overload forces and resisting cyclic fatigue than the method using 3 parallel transarticular screws (3-TLS).

Objective

The study aimed to compare the in vitro monotonic biomechanical properties of two surgical techniques used in equine PIP joint arthrodesis. Specifically, researchers tested an axial 3-hole narrow dynamic compression plate with 2 abaxial transarticular cortical screws against the technique that uses 3 parallel transarticular cortical screws.

Methods

• The researchers utilized cadaveric adult equine forelimbs (15 pairs in all) for their testing.
• In each pair, the PIP joint was stabilized using both techniques – one limb used the DCP-TLS method and the other used 3-TLS method.
• Each set of constructs were subjected to three tests:
  • Single cycle to failure under axial compression
  • Cyclic fatigue under axial compression
  • Single cycle to failure under torsional loading
• A paired t-test was conducted for each group to compare mean values for each fixation method, with statistical significance set at P<.05.

Results

• The yield load, yield stiffness, and failure load under axial compression and torsion (single-cycle to failure) of the DCP-TLS fixation technique was found to be significantly greater than the 3-TLS method.
• The number of cycles to failure in axial compression for the DCP-TLS technique was also significantly greater than that of the 3-TLS fixation.

Conclusion

The researchers concluded that the DCP-TLS method is superior to the 3-TLS technique in withholding static overload forces and resisting cyclic fatigue. These findings can potentially guide clinicians in determining the most appropriate surgical technique for equine PIP joint arthrodesis.