A review of tendon injury: Why is the equine superficial digital flexor tendon most at risk?
Authors: THORPE C. T., CLEGG P. D., BIRCH H. L.
Journal: Equine Veterinary Journal
Summary
# Editorial Summary Tendon injuries represent a substantial cause of lost performance time and early retirement in horses, yet injury rates are not equally distributed across the forelimb—the superficial digital flexor tendon (SDFT) accounts for the majority of failures whilst injuries to the common digital extensor tendon remain rare. Thorpe and colleagues conducted a comprehensive review of the epidemiological and biomechanical literature to establish why the SDFT is uniquely vulnerable, examining both the structural demands placed on different tendons during locomotion and the intrinsic tissue properties that predispose to failure. The authors identified that the SDFT's anatomical position, loading patterns during stance and flight phases, and inherent matrix composition create a "perfect storm" of mechanical stress and biological susceptibility compared to its neighbouring tendons. Understanding the pathophysiological cascade from initial matrix degeneration through to gross tendon rupture is critical for developing evidence-based interventions. For practitioners, this synthesis emphasises that preventative strategies must account for the SDFT's specific biomechanical role and tissue vulnerabilities—informing decisions around training load management, farriery, conditioning protocols, and rehabilitation approaches.
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Practical Takeaways
- •SDFT injuries are the primary concern in performance horses—focus preventative efforts on this structure through conditioning, workload management, and monitoring
- •Different forelimb tendons have different functional demands and failure rates; tailor rehabilitation protocols based on specific tendon biomechanics
- •Early recognition of matrix degeneration before gross failure allows for intervention; maintain high index of suspicion for subclinical SDFT changes in performance horses
Key Findings
- •Tendon injury is one of the most common causes of wastage in performance horses, with the majority occurring to the SDFT rather than other forelimb tendons
- •The SDFT has a higher failure rate than the common digital extensor tendon despite similar loading patterns
- •Understanding matrix degeneration mechanisms is essential for developing effective treatment and prevention strategies for tendon injury