An in vitro evaluation of plate luting using osteotomized equine third metacarpal bones with a limited contact-dynamic compression plate.
Authors: Sod Gary A, Hubert Jeremy D, Martin George S, Gill Marjorie S
Journal: Veterinary surgery : VS
Summary
# Editorial Summary Repair of third metacarpal fractures in horses represents a significant surgical challenge, and the biomechanical stability of fixation methods directly influences healing outcomes and return to athletic function. Researchers conducted an in vitro study using paired cadaveric equine third metacarpal bones with mid-diaphyseal osteotomies, comparing limited contact-dynamic compression plate (LC-DCP) fixation with and without polymethylmethacrylate (PMMA) luting under both single-cycle failure loading and cyclic fatigue conditions. Whilst luting did not significantly affect yield or failure moments under single-load testing, cyclic fatigue performance improved dramatically: luted constructs demonstrated a 7.2-fold increase in cycles to failure compared with non-luted plates (P<0.0003). This finding suggests that PMMA augmentation substantially enhances the fatigue resistance of dorsal plate fixation, which is clinically relevant since equine third metacarpal fractures are subjected to repetitive high-magnitude cyclic loading during weight-bearing and exercise. For practitioners managing these injuries, plate luting warrants consideration in cases where extended healing timescales or early rehabilitation loading is anticipated, though the clinical translation of these in vitro results requires further validation in living subjects.
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Practical Takeaways
- •If using broad LC-DCP plates for third metacarpal fracture repair in horses, luting with PMMA substantially improves the construct's ability to withstand repetitive loading and may reduce risk of fatigue failure during recovery
- •Although luting doesn't change the initial strength of the repair, it provides a significant safety margin for horses returning to athletic work where cyclic stress is high
- •This technique should be considered particularly valuable for high-performance horses or those where strict stall rest cannot be maintained during healing
Key Findings
- •Plate luting with PMMA did not significantly affect yield or failure bending moments in single-cycle loading (P > 0.05)
- •Luted LC-DCP constructs showed a 7.2-fold increase in cycles to failure under cyclic loading compared to non-luted plates (P < 0.0003)
- •PMMA luting significantly improved fatigue resistance of LC-DCP fixation in osteotomized equine MC3 bones