Asymmetry Thresholds Reflecting the Visual Assessment of Forelimb Lameness on Circles on a Hard Surface.
Authors: Macaire Claire, Hanne-Poujade Sandrine, De Azevedo Emeline, Denoix Jean-Marie, Coudry Virginie, Jacquet Sandrine, Bertoni Lélia, Tallaj Amélie, Audigié Fabrice, Hatrisse Chloé, Hébert Camille, Martin Pauline, Marin Frédéric, Chateau Henry
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Asymmetry Thresholds for Forelimb Lameness Detection on Circles Whilst objective gait analysis has become increasingly valuable in lameness diagnosis, practical asymmetry thresholds for circle work—a standard veterinary assessment protocol—have been lacking until now. Researchers compared kinematic data from sound horses and those with confirmed unilateral forelimb lameness during trotting on circles in both directions, validating their findings against visual assessments by specialist equine veterinarians. Head vertical displacement asymmetry indices achieved sensitivity and specificity of ≥69% and ≥81% respectively for detecting inside forelimb lameness, whilst withers asymmetry indices performed best for outside forelimb lameness (≥72% sensitivity, ≥77% specificity)—importantly distinguishing pathological asymmetry from the physiologically normal asymmetry imposed by circling itself. These validated thresholds offer farriers, veterinarians and rehabilitation professionals a quantifiable benchmark for circle-based lameness assessment, bridging the gap between subjective visual evaluation and objective measurement and potentially improving diagnostic consistency across different examiners and situations.
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Practical Takeaways
- •Use head motion asymmetry measurements when assessing suspected inside forelimb lameness on circles, and withers motion for outside forelimb lameness—these show superior diagnostic reliability
- •Objective gait analysis tools with established asymmetry thresholds can now support visual lameness assessment during circle work, reducing subjective interpretation errors
- •Circular trotting creates physiological asymmetries that must be distinguished from lameness-related asymmetries; use these validated thresholds as diagnostic cutoffs in your practice
Key Findings
- •Head asymmetry indices achieved ≥69% sensitivity and ≥81% specificity for detecting inside forelimb lameness on circles
- •Withers asymmetry indices achieved ≥72% sensitivity and ≥77% specificity for detecting outside forelimb lameness on circles
- •Asymmetry index of maxima difference was the least reliable discriminator between sound and lame horses
- •Specific asymmetry thresholds were established to distinguish physiological asymmetry from pathological lameness during circular trotting