Model formulation and determination of in vitro parameters of a noninvasive method to calculate flexor tendon forces in the equine forelimb.

This study describes a method for calculating forces on horse’s flexor tendons using a non-invasive technique based on an in vitro model of the horse’s forelimb and inverse dynamic analysis. It measures several mechanical properties and quantifies parameters, which could be invaluable in understanding, preventing and treating tendon injuries in horses.

Methodology

• The study worked with 38 forelimbs from 23 horses, each weighing around 500 kg or more. Using this sample, the research sought to develop a detailed and accurate model of equine tendon forces.
• The researchers made longitudinal sections of the limbs to determine the lines of action of the tendons. Assuming the tendons functioned like pulleys, this approach helped them understand the way the force is transmitted through the tendons.
• In addition to determining the lines of action, the researchers conducted limb and tendon loading experiments to determine the mechanical properties of the flexor tendons.

Results

• Based on their studies, the researchers were able to quantify parameters for a pulley-like model describing the lines of action of the tendons.
• They established relationships between force and strain in the flexor tendons and between the fetlock joint angle and strain in the suspensory ligament.
• The ultimate strength of the tendons, a crucial factor for assessing tendon health and resilience, was also measured.

Conclusions

• The model developed through this research allows for the noninvasive calculation of forces in various tendons in the equine forelimb. These include the suspensory ligament, superficial digital flexor tendon, and the distal part of the deep digital flexor (DDF) tendon.
• The model further provides a noninvasive measure of loading in the accessory ligament of the DDF tendon, enabling comparisons within the same subject.
• Despite these promising results, the researchers recommend the method to be validated before its application.
• Once fully validated, this model could become a significant tool in researching the causes, prevention methods, and treatment options for tendon injuries in horses.