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.
Authors: Zoppa André L V, Santoni Brandon, Puttlitz Christian M, Cochran Kayla, Hendrickson Dean A
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: PIP Arthrodesis Plate Comparison Proximal interphalangeal joint arthrodesis in horses requires robust fixation, yet the optimal implant combination remains debated. Researchers conducted a paired biomechanical study using six cadaveric equine forelimbs, comparing two plating approaches—locking compression plates (LCP) versus narrow dynamic compression plates (DCP)—each supplemented with two transarticular cortex screws. Both constructs were subjected to 20,000 cycles of axial loading in four 5,000-cycle increments, with measurements of stiffness, gap formation across the joint, and sagittal plane rotation taken at baseline and after each loading phase, followed by load-to-failure testing. No statistically significant differences emerged between the LCP and DCP groups across any measured parameter at any time point during cyclic loading or at failure. This finding suggests that within the context of transarticular screw fixation, the choice between these two plate designs does not substantially influence the mechanical performance of the arthrodesis construct. For practitioners, this equivalence offers valuable flexibility in implant selection, allowing decisions to be guided by factors such as cost, surgical familiarity, and local tissue considerations rather than biomechanical advantage. However, the study's reliance on cadaveric tissue and artificial loading patterns warrants caution in extrapolating to in vivo performance, where biological healing, load magnitude, and joint kinematics may diverge from laboratory conditions.
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Practical Takeaways
- •Either the locking compression plate or dynamic compression plate can be selected for equine PIP arthrodesis based on surgeon preference and availability, as biomechanical performance is equivalent
- •Both plate types maintained construct stability through 20,000 loading cycles, suggesting either is suitable for supporting early mobilization in clinical cases
- •When combined with two transarticular cortex screws, both 3-hole 4.5 mm plate designs provide comparable resistance to gap formation and rotation
Key Findings
- •No significant differences in construct stiffness between 3-hole 4.5 mm LCP and DCP fixation techniques
- •Gap formation across the PIP joint was equivalent between both plate types over 20,000 cycles of axial loading
- •Sagittal plane rotation about the PIP joint showed no significant differences between LCP and DCP constructs
- •Both fixation techniques demonstrated biomechanical equivalence under cyclic loading conditions up to failure