Heel elevation can reduce the strain on a horses flexor tendons. | Adobe StockResearchers have reported that therapeutic heel elevation can reduce strain in horses flexor tendons, but the magnitude of that reduction depends on the angle applied, the individual horse, the tendon involved, and even the region of the tendon. They also confirmed a method of directly quantifying tendon strain in these animals.In the study, scientists at the University of Wisconsin School of Veterinary Medicine (SVM), in Madison, evaluated live, healthy horses and observed reduced strain in both the superficial and deep digital flexor tendons (SDFT and DDFT). However, the degree of change varied considerably among horses. Within each tendon, variability increased closer to joints and tendon insertion sites, where changes in joint angulation exert greater mechanical influence.Kelly Shaw, DVM, co-founder of Trinity Equine ?Hospital, in Anderson, California, and a former researcher in UWMadison SVMs Department of Surgical Sciences, said the findings highlight the importance of more targeted, horse-specific therapeutic shoeing rather than standardized heel prescriptions.To maximize the benefit of therapeutic shoeing interventions, an understanding of both the horses natural conformation and the effect that applied mechanics has on the baseline anatomy is needed, she said. This knowledge will allow for a more customized shoeing that will enhance recovery considering the individual horses needs.Why Veterinarians Use Therapeutic Heel ElevationVeterinarians use therapeutic heel elevation to manage a range of distal limb problems, including laminitis, navicular-related pain, and flexor tendon injuries. Their goal: to alter digital alignment, reduce tension on affected structures, and redistribute forces within the hoof and lower limb. Shaw said adjusting heel height to reduce pain and support healing captured her interest and led her to investigate further.I experienced how the application of varying degrees of heel elevation could save a life and wanted to better understand how on both an anatomical and mechanical level, she explained.How Researchers Measured Tendon Strain in Live HorsesTo explore this question Shaw and senior collaborator Sabrina Brounts, DVM, MS, PhD, Dipl. ACVS, ECVS, also from the UWMadison SVM, evaluated flexor tendon strain in 15 clinically normal horses of various breeds ranging from 3 to 22 years old.The researchers incrementally increased heel elevation from 0 to 8 degrees in each forelimb using slip-on orthotics. They then used acoustoelastography, a specialized ultrasound-based technique that measures tendon strain in standing horses, to assess multiple locations along each tendon. By alternately loading and unloading the limb, the team captured how the tendons responded under weight-bearing conditions.Equine Tendon Response to Heel ElevationIncreasing heel elevation up to 8 degrees generally reduced strain in both the SDFT and the DDFT, though the magnitude of reduction differed among horses, Shaw said. The most consistent strain reduction occurred in the mid-cannon region, while more variable effects appeared closer to joints and tendon insertion points.Although the findings confirmed Shaws suspicion that tendon strain responses to heel elevation were likely more complex than previously thought, she said she was surprised by the variation seen along different regions of the same tendon within individual forelimbs.What the Findings Mean for Therapeutic Shoeing in HorsesMoving forward, equine health care professionals should keep individual variation in mind when considering how heel elevation might affect tendon strain in horses, said Shaw. Ideally, acoustoelastography could expand beyond research settings and into clinical veterinary practice to help guide therapeutic decisions in real time.It would be great to see this modality be used for more clinical applications, as there is such potential for the information acquired to improve upon the application of therapeutic shoes and/or orthotics to the individual horse, she said.I believe that continuing this research is essential as it could revolutionize how we manage cases with extreme pathology of the distal limb, Shaw added. We are at the tip of the iceberg, and Im excited to see what more lies below the surface.