Three-dimensional kinematics of the equine interphalangeal joints: articular impact of asymmetric bearing.

This research study investigates the impact of uneven weight distribution on the three-dimensional movement of joints between phalanges (bones) in a horse’s forelimb, in an attempt to understand contributing factors to joint injuries and inform future care strategies.

Research Methodology

The researchers in this study made use of four isolated horse forelimbs.

• They attached trihedrons (three-dimensional figures) fitted with reflective markers to each phalanx to establish a local frame and define the spatial orientation of the phalanges.
• The limbs were then placed under a power press and subjected to compression with gradually increasing force, ranging from 500N to 6000N.
• This procedure was performed not only in a neutral position but also with the lateral or medial part of the foot raised by a 12 degrees wedge.

Data Collection

They measured the flexion, collateromotion (passive abduction/adduction) and axial rotation of these interphalangeal joints by using a Cardan angle decomposition, which follows the “Joint Coordinate System” principle described by scientists Grood and Suntay.

• Raising the lateral or medial part of the hoof induced collateromotion and axial rotation of the distal interphalangeal joint.
• The proximal interphalangeal joint demonstrated axial rotation and slight collateromotion.
• Both interphalangeal joints showed collateromotion in the direction of the raised part of the foot, leading to narrowing of the articular space on the side of the wedge.
• Axial rotation occurred in the opposite direction to the raised part of the foot.

Research Findings

The study concludes that the interphalangeal joint movements outside the sagittal plane are functionally significant. Specifically, the involvement of the proximal interphalangeal joint in maintaining the balance of the digit is quite important.

• The results obtained from this research are crucial in identifying potential biomechanical factors that could predispose a horse to interphalangeal joint injury.
• Such findings could guide decision making related to exercise management and corrective shoeing for horses dealing with lameness or other conditions.