An in vitro biomechanical comparison of a prototype intramedullary pin-plate with a dynamic compression plate for equine metacarpophalangeal arthrodesis.
Authors: Sod Gary A, Martin George S
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Intramedullary Pin-Plate versus Dynamic Compression Plate for Equine MCP Arthrodesis When the suspensory apparatus fails catastrophically in the equine forelimb, arthrodesis of the metacarpophalangeal joint offers a salvage option, but implant selection significantly influences biomechanical stability and long-term success. Sod and Martin compared a custom-designed intramedullary pin-plate (IMPP) against the standard dynamic compression plate (DCP) using cadaveric forelimb pairs with surgically severed distal sesamoidean ligaments, testing each construct to failure under axial compression and torsional loading, plus subjecting paired samples to fatigue cycling. The IMPP demonstrated substantially superior performance across all parameters: significantly higher yield loads, yield stiffness, and failure loads in both compression and torsion testing (P<0.0001), alongside greater cycles to failure during fatigue testing—findings that directly translate to superior resistance against the repetitive cyclic forces that typically cause arthrodesis failure in weight-bearing limbs. For practitioners managing horses with complete suspensory apparatus disruption, these results suggest the IMPP may offer improved long-term stability and reduced risk of implant-related complications, though access to this prototype implant and comparative data on functional outcomes in live horses would strengthen clinical decision-making.
Read the full abstract on PubMed
Practical Takeaways
- •The IMPP implant is biomechanically superior to standard DCP systems for MCP arthrodesis in horses with suspensory apparatus damage, particularly where high cyclic loading is expected
- •Consider IMPP for cases where fatigue failure is a primary concern, as it resists repetitive loading forces significantly better than traditional plate fixation
- •This specialized implant design may improve success rates and reduce the need for revision surgery in performance horses requiring MCP fusion
Key Findings
- •Intramedullary pin-plate (IMPP) demonstrated significantly greater yield load, yield stiffness, and failure load compared to dynamic compression plate (DCP) in axial compression testing (P<0.0001)
- •IMPP showed significantly superior torsional resistance compared to DCP system (P<0.0001)
- •IMPP exhibited significantly greater cycles to failure in fatigue testing of axial compression compared to DCP (P<0.0001)
- •IMPP implant design specifically optimized for equine MCP arthrodesis may reduce convalescent complications from cyclic fatigue loading