Influence of support boots on fetlock joint angle of the forelimb of the horse at walk and trot.
Authors: Kicker C J, Peham C, Girtler D, Licka T
Journal: Equine veterinary journal
Summary
# Editorial Summary: Support Boots and Fetlock Biomechanics Kicker and colleagues investigated whether support boots genuinely reduce stress on the superficial digital flexor tendon (SDFT) by measuring changes in fetlock joint kinematics across 26 horses fitted with three support boot types and one protective boot, compared to unshod locomotion on a treadmill at both walk and trot. At walk, two of the support boots significantly reduced maximum fetlock extension by 0.8–0.9°, with one also delaying peak extension within the stride cycle; at trot, all support boots produced significant reductions of 0.56–1.44°, demonstrating consistent biomechanical effects across gaits. These findings support the theoretical basis for support boot prescription during tendon rehabilitation—namely, that reduced fetlock extension directly translates to decreased tension in the suspensory apparatus and SDFT. However, the authors appropriately flag an important caveat: whilst acute reduction of fetlock extension may relieve pain and load during the early phases of healing, prolonged restriction of normal joint motion could potentially compromise collagen fibre alignment in the regenerating tendon, raising questions about long-term functional outcomes that remain unanswered. Practitioners should therefore view support boots as a short-term therapeutic tool with proven biomechanical efficacy, rather than a prolonged solution, and integrate them strategically within broader rehabilitation protocols that eventually restore normal motion.
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Practical Takeaways
- •Support boots demonstrably reduce fetlock joint extension during both walk and trot, suggesting mechanical protection of injured flexor tendons during early rehabilitation
- •Boot efficacy varies by type and gait; all boots work at trot but only some are effective at walk, so selection should match the horse's primary activity level
- •While reduced extension theoretically protects acutely injured tendons, prolonged use may compromise normal tendon fiber remodeling during healing—use judiciously and avoid indefinite application
Key Findings
- •At walk, 2 of 4 support boots significantly reduced maximum fetlock extension by 0.8–0.9 degrees (P<0.05)
- •At trot, all support boots significantly reduced maximum fetlock extension by 0.56–1.44 degrees (P<0.01)
- •One support boot delayed the timing of maximal fetlock extension within the stride cycle
- •Reduction in fetlock extension may reduce tension in the suspensory apparatus and SDFT, but long-term effects on healing tendon fiber alignment remain uncertain