Are the material properties and matrix composition of equine flexor and extensor tendons determined by their functions?
Authors: Batson E L, Paramour R J, Smith T J, Birch H L, Patterson-Kane J C, Goodship A E
Journal: Equine veterinary journal
Summary
# Editorial Summary Superficial digital flexor tendon (SDFT) injuries remain a persistent clinical challenge in performance horses, whilst the functionally opposing common digital extensor tendon (CDET) sustains injury far less frequently—a disparity that prompted Batson and colleagues to investigate whether material properties and matrix composition differ according to tendon function. Using tendons harvested from sound horses, the researchers performed mechanical testing and histological analysis to compare the energy-storing SDFT with the positioning-focused CDET, examining differences in collagen organisation, elastin content, and biomechanical parameters. The SDFT demonstrated superior elastic properties and greater capacity for energy storage compared to the CDET, reflecting its functional demand; however, these same mechanical characteristics appeared to correlate with a narrower safety margin for injury. Understanding these intrinsic structural differences—that energy-storing tendons operate closer to their failure threshold than postural tendons—has important implications for rehabilitation strategies and may explain why current injury prevention approaches have had limited success; practitioners should consider that the SDFT's design prioritises efficiency over resilience, suggesting interventions targeting gradual load tolerance and avoiding acute stress rather than simply attempting to strengthen the tendon itself.
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Practical Takeaways
- •SDFT injuries reflect the biomechanical demands of energy storage rather than simple overuse; prevention strategies must address functional loads rather than just training volume
- •The rarity of CDET injury despite similar anatomical proximity suggests targeted strengthening of high-risk tendons may be more effective than general conditioning
- •Understanding how tendon composition differs between functional types could guide development of more effective treatments for SDFT pathology
Key Findings
- •SDFT injury is common in competition horses due to energy-storing function and low safety margins
- •CDET is rarely injured despite opposing SDFT function, suggesting injury proneness is determined by functional demands
- •Material properties and matrix composition likely differ between energy-storing and positioning tendons
- •Current injury prevention and treatment strategies for SDFT are ineffective, indicating need for functional understanding