Three‐dimensional kinematics of the tarsal joint at the trot
Authors: LANOVAZ J. L., KHUMSAP S., CLAYTON H. M., STICK J. A., BROWN J.
Journal: Equine Veterinary Journal
Summary
# Editorial Summary: Three-Dimensional Kinematics of the Tarsal Joint at the Trot The tarsal joint remains a frequent source of lameness in sport horses, yet detailed understanding of its normal biomechanical function during locomotion has been limited. Lanovaz and colleagues used an invasive marker technique to characterise tarsal motion in four sound Quarter Horses, attaching steel pins directly to the tibia and third metatarsus with motion-tracking markers; three-dimensional kinematics were then recorded as horses trotted in hand and analysed using finite helical angle methodology. Whilst the tarsocrural joint dominated overall tarsal motion, the researchers identified significant rotational and translational movements occurring elsewhere within the tarsal complex—particularly internal/external rotation during stance phase and medio-lateral translations during swing phase—findings that suggest mechanical complexity beyond simple hinge-joint function. Notably, some of these non-coupled movements correlated with the clinically observable 'snapping' phenomenon occasionally heard during tarsal joint flexion. For practitioners managing tarsal lameness, this foundational kinematic dataset provides a critical reference for recognising abnormal motion patterns and understanding how degenerative or traumatic tarsal conditions might disrupt the joint's sophisticated multi-planar mechanics, potentially informing both diagnostic and rehabilitative approaches.
Read the full abstract on the publisher's site
Practical Takeaways
- •Tarsal lameness involves complex multi-joint motion patterns beyond simple tarsocrural flexion—understanding these helps diagnose non-obvious injuries
- •The 'snapping' sensation riders feel likely reflects normal intertarsal motion during trot; abnormal snapping may indicate joint pathology
- •Reference kinematics from sound horses provide a baseline to identify biomechanical dysfunction in tarsal-lame individuals
Key Findings
- •Most tarsal motion occurs at the tarsocrural joint, but significant translations and rotations occur at other intertarsal articulations
- •Internal/external rotation during stance phase and translations during swing phase show motion independent of flexion angle
- •Evidence supports a mechanical basis for tarsal joint 'snapping' phenomenon through coupled and noncoupled motions
- •3D kinematic reference data established for 4 sound Quarter Horses at trot with direct bone-mounted markers