Effect of forelimb lameness on hoof kinematics of horses at a trot.

This research study explores how the onset of unilateral, weight-bearing lameness in a horse’s forelimb affects hoof kinematics when the animal is trotting. The research shows that lameness significantly changes the hoof’s movement and these changes seem not to entirely revert back even following the administration of perineural anesthesia intended to relieve lameness.

Methods and Procedures

• The study was conducted using six clinically normal Quarter Horses. The researchers induced three levels of lameness (grades 1, 2, and 3) in the right forelimb of each horse using a sole-pressure model. After inducing lameness, perineural anesthesia was administered with the aim of relieving the lameness.
• Horses were made to trot and optical kinematic data was collected for both forelimbs before and after the induction of lameness, as well as after the administration of anesthesia.
• The researchers identified different stages in each stride, such as hoof-contact, break-over, initial-swing, terminal-swing, and total-swing, and studied kinematic changes during each stage.
• The data was then compared within and between limbs using a mixed repeated-measures ANOVA statistical model.

Findings and Results

• The data showed that during hoof-contact, the hoof of the left (nonlame) forelimb had a greater heel-down orientation compared to the right (lame) forelimb.
• Furthermore, at the break-over stage, the nonlame hoof went through a larger range of motion than the lame hoof.
• There was a significantly greater maximum cranial acceleration during break-over for the lame hoof in comparison to the baseline or the nonlame hoof.
• After administering perineural anesthesia, there was no noticeable variation in the sagittal plane orientation of the hoof during hoof-contact between the lame and nonlame limbs. However, differences in maximum cranial acceleration and angular range of motion during break-over persisted.

Conclusions of the Study

• The findings of the study suggest that observing hoof kinematics can be useful in detecting unilateral, weight-bearing forelimb lameness in trotting horses.
• Despite using anesthesia to alleviate lameness, some changes to hoof kinematics remained, suggesting that these alterations may be somewhat resilient or that the anesthesia was not entirely effective.