The influence of a tension band fixation as an adjunct for arthrodesis of the metacarpophalangeal joint in the horse.
Authors: Kadic Lawrence I M, Rademacher Nathalie, Liu Chin-Chi, Leise Britta S, McCauley Charles T, Riggs Laura M
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Arthrodesis of the equine metacarpophalangeal joint is a common surgical procedure for managing severe joint disease, but optimal fixation techniques remain debated. Lawrence and colleagues conducted an ex vivo biomechanical study using five paired cadaver limbs from Thoroughbreds to evaluate whether adding a stainless-steel cable tension band to a standard locking compression plate (LCP) improves construct stability during arthrodesis. Under cyclic loading at 1 kN over 3600 cycles, both constructs (LCP alone versus LCP plus tension band) demonstrated excellent stability with maximum displacements under 1.1 mm and no significant difference between initial and final cycles, whilst the tension band addition did not alter yield load but did significantly increase maximum load to failure (p = 0.046). These findings suggest that whilst the tension band provides additional ultimate strength, it may not be biomechanically necessary for maintaining joint stability during the early healing phases when cyclic loading is most relevant clinically. For practitioners, this implies that single-plate fixation without tension band augmentation may be sufficient for routine MCP arthrodesis cases, potentially reducing operative time and cost without compromising short-term construct performance, though clinical follow-up studies would help validate whether this biomechanical advantage translates to improved long-term outcomes.
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Practical Takeaways
- •For equine MCP arthrodesis, a locking compression plate alone appears mechanically sufficient under normal cyclic loading; tension band addition may not be necessary for routine cases
- •The tension band increases ultimate failure load but this gain may not be clinically significant since cyclic displacement is already minimal with plate fixation alone
- •Simpler fixation with LCP alone could reduce surgical time and cost without compromising short-term biomechanical stability
Key Findings
- •Cyclic displacement was minimal (<1.1 mm) and did not differ significantly between locking compression plate (LCP) alone and LCP with stainless-steel cable tension band over 3600 cycles
- •Yield point did not differ significantly between LCP and LCP-SSC constructs (p = 0.440)
- •Maximum load at failure was significantly higher in LCP-SSC compared to LCP alone (p = 0.046)
- •Tension band fixation does not substantially improve construct stability during physiological cyclic loading in MCP arthrodesis