Variation in frontal plane joint angles in horses.

This research study analysed how locomotion affects joint angles in horses and found significant differences both between groups of horses and between individual animal’s left and right forelimbs.

Objective

• The main aim of the research was to ascertain the influence of movement on the carpus, tarsus, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints, which are located in the legs of horses.
• The authors hypothesized that the valgus or varus angulation (outward angle and inward angle respectively) of these joints will fluctuate during movement.

Methods

• Using kinematics, which is a branch of mechanics that deals with the motion of objects without reference to its causes, the researchers gathered the data from the horses while they stood, walked and trotted.
• They calculated the change in angle for carpus, tarsus, MCP, and MTP joints both while the horses were stationary and at midstance (mid-point in a stride) for each stride.
• Further, they compared the joint angles between the horse’s left and right limbs and explored both interhorse (between different horses) and intrahorse (within the same horse) variations.

Results

• There were meaningful differences between the horse groups and within the left and right forelimbs of individual horses, validating that valgus and varus angulation occur during movement.
• Between walking and trotting, the MCP joint changed from valgus to varus, highlighting a meaningful movement-related alteration.
• Moreover, the tarsus and MTP joints increased their valgus deformity when the horses picked up pace from a walk to a trot.
• On changing from a stationary stance to walking, the carpus also increased in valgus deformity.
• Interhorse variation appeared to be significant, but not the intrahorse variation, suggesting that variations in joint angles are more dependent on the individual horse rather than on different walking or trotting speeds.

Conclusion

• The study confirms that the measurement of joint angles from the front in the walking and trotting horse using kinematic data is valid.
• The difference in variations between different horses and also the changes in joint angles between standing and walking, or between walking and trotting, warrant further investigation.