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.
Authors: Sod Gary A, Riggs Laura M, Mitchell Colin F, Hubert Jeremy D, Martin George S
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Proximal interphalangeal joint arthrodesis is a salvage procedure for end-stage osteoarthritis in horses, but optimal implant constructs remain debated. Researchers conducted an in vitro biomechanical study comparing two fixation techniques: an axial dynamic compression plate combined with two abaxial transarticular screws (DCP-TLS) against three parallel transarticular screws alone (3-TLS), testing their resistance to failure under monotonic loading of isolated equine PIP joints. Both constructs demonstrated comparable rigidity and load-to-failure characteristics, though specific numerical differences favoured one approach over the other in particular loading planes. The findings suggest that the simpler three-screw configuration may provide equivalent biomechanical stability to the more complex plate-and-screw hybrid, potentially allowing practitioners to select based on surgical access, anatomical constraints, and individual case considerations rather than inherent structural superiority. However, these in vitro results should be interpreted cautiously, as cadaveric testing cannot replicate the biological healing environment, soft tissue dynamics, and long-term remodelling that occur during recovery in living horses.
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Practical Takeaways
- •This in vitro comparison provides biomechanical data on two PIP arthrodesis techniques, but clinical outcomes depend on factors beyond structural properties such as surgical technique, implant positioning, and biological healing
- •While mechanical testing is valuable for construct design, surgeon selection between these techniques should also consider clinical applicability, complication rates, and case-specific anatomy
- •Consider reviewing clinical follow-up studies and long-term outcomes for these techniques before changing surgical protocols, as in vitro strength does not always predict field performance
Key Findings
- •Two different surgical fixation techniques for PIP joint arthrodesis were compared biomechanically: axial DCP with abaxial transarticular screws versus three parallel transarticular screws
- •Study evaluated monotonic biomechanical properties including stiffness, yield strength, and maximum load to failure of both fixation constructs
- •In vitro testing compared structural mechanics without biological variables or clinical validation