3D kinematics of the equine metacarpophalangeal joint at walk and trot
Authors: Sha D., Stick J., Elvin N., Clayton H. M.
Journal: Veterinary and Comparative Orthopaedics and Traumatology
Summary
# Editorial Summary: 3D Kinematics of the Equine Metacarpophalangeal Joint at Walk and Trot The metacarpophalangeal joint is notoriously vulnerable to injury in ridden and competition horses, yet most gait analysis research has traditionally examined movement in only two dimensions, leaving significant gaps in our understanding of how complex three-dimensional motion might contribute to soft tissue pathology. Sha and colleagues used eight infra-red cameras operating at 120 Hz to track rigid marker clusters attached to the third metacarpus and proximal phalanx of the right forelimb in healthy horses at walk and trot, quantifying all three planes of motion using advanced mathematical modelling. The MCP joint demonstrated substantially greater flexion/extension range at trot (77°) compared to walk (62°), with consistent coupling between extension and abduction during stance phase and flexion with adduction during swing phase; frontal plane adduction/abduction ranged from 13–18° depending on gait, whilst axial rotation remained modest at 6–9° but showed individual variation in direction. These findings matter clinically because they reveal that MCP joint injury risk may be influenced not just by sagittal plane forces, but by the coordinated three-dimensional stresses occurring particularly during transitions and weight-bearing phases—information that should inform farriery trim decisions, rehabilitation protocols, and pre-purchase or lameness investigations.
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Practical Takeaways
- •The strong coupling of flexion with adduction and extension with abduction suggests that forelimb movement patterns are more complex than 2D sagittal plane analysis reveals—asymmetrical loading or deviation from normal coupled patterns may predispose to MCP injury
- •Individual variation in axial rotation means that some horses may have inherently different MCP loading patterns; identify outliers with unusual rotation patterns as potentially higher-risk for joint problems
- •Understanding normal 3D MCP mechanics provides a biomechanical baseline for evaluating lameness and designing appropriate rehabilitation protocols
Key Findings
- •MCP joint flexion/extension ranges from 62° at walk to 77° at trot, significantly larger than adduction/abduction (13-18°) and axial rotation (6-9°)
- •Stance phase extension is coupled with abduction while swing phase flexion is coupled with adduction in consistent patterns across all horses
- •Axial rotation is minimal and variable between individual horses but remains consistent within each horse across different gaits
- •3D kinematic analysis reveals previously undescribed coupling patterns that may be relevant to understanding MCP joint injury mechanisms