Three-dimensional kinematics of the equine distal forelimb: effects of a sharp turn at the walk.

The research article investigates how sharp turns, even at a slow walk, could potentially increase the expression of equine distal forelimb lameness. They used a 3D modelling technique to study the impact of sharp turns on the forelimbs of healthy horses, examining how the joints moved during these turns. They concluded that such turns can affect the kinematics of the limb, providing insight into potential causes of digital injuries and implications for proper horse shoeing.

Objective

• The objective of this research was to understand the potential biomechanical effects of sharp turns at a walking pace on the movement of the equine distal forelimb. There was suspicion that such movements may contribute to lameness in these limbs, but no clear biomechanical understanding.

Methods

• The researchers employed a kinematic approach to study the effects. They attached an ultrasonic system to the limbs of four healthy horses and collected data on three-dimensional movement of the distal segments during sharp turns at a walking pace.
• The rotations of the digital joints were calculated using a joint coordinate system. This data was compared to movement data collected when the horses moved in a straight line.

Results

• The findings showed that during the stance phase of a turn, the inside forelimb undergoes an inward movement that results in lateral motion and medial rotation in the distal interphalangeal joint, along with medial rotation in the proximal interphalangeal joint.
• These movements were observed to be most extreme at the point of heel-off and gradually decreased during the ‘breakover’ phase where the hoof undergoes sudden lateral rotation.

Conclusions

• Based on the findings, the researchers concluded that walking in sharp turns can affect the movements of the digital joints outside the normal planes, which could potentially exacerbate the expression of distal forelimb lameness in horses.
• Such an understanding can provide hypotheses about biomechanical factors that could contribute to digital injuries in horses. It also sheds light on relevant considerations for rational shoeing, an aspect of equine care that involves fitting horseshoes to protect the hooves and aid in balanced movement.