Effect of video angle on detection of induced front limb lameness in horses

In a trotting horse, it is the change in symmetry that best indicates the lame limb at lower grades of lameness. Conversely to the front limb assessment, for a hindlimb lameness watching the horse trot straight away from you is the most informative view.
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Effect of video angle on detection of induced front limb lameness in horses
BMC Vet Res. 2024 May 3;20(1):172. doi: 10.1186/s12917-024-04032-9.
Authors
Alessandro P Valle 1 , Kara A Brown 1 , Patrick Reilly 1 , Sarah A Ciamillo 1 , Elizabeth J Davidson 1 , Darko Stefanovski 1 , Holly L Stewart 1 , Kyla F Ortved 2
Affiliations

1 Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Road, Kennett Square, Philadelphia, PA, 19348, United States of America.
2 Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Road, Kennett Square, Philadelphia, PA, 19348, United States of America. kortved@vet.upenn.edu.

PMID: 38702691
DOI: 10.1186/s12917-024-04032-9

Abstract

Background: Lameness examinations are commonly performed in equine medicine. Advancements in digital technology have increased the use of video recordings for lameness assessment, however, standardization of ideal video angle is not available yielding videos of poor diagnostic quality. The objective of this study was to evaluate the effect of video angle on the subjective assessment of front limb lameness. A randomized, blinded, crossover study was performed. Six horses with and without mechanically induced forelimb solar pain were recorded using 9 video angles including horses trotting directly away and towards the video camera, horses trotting away and towards a video camera placed to the left and right side of midline, and horses trotting in a circle with the video camera placed on the inside and outside of the circle. Videos were randomized and assessed by three expert equine veterinarians using a 0-5 point scoring system. Objective lameness parameters were collected using a body-mounted inertial sensor system (Lameness Locator®, Equinosis LLC). Interobserver agreement for subjective lameness scores and ease of grading scores were determined.

Results: Induction of lameness was successful in all horses. There was excellent agreement between objective lameness parameters and subjective lameness scores (AUC of the ROC = 0.87). For horses in the “lame” trials, interobserver agreement was moderate for video angle 2 when degree of lameness was considered and perfect for video angle 2 and 9 when lameness was considered as a binary outcome. All other angles had no to fair agreement. For horses in the “sound” trials, interobserver agreement was perfect for video angle 5. All other video angles had slight to moderate agreement.

Conclusions: When video assessment of forelimb lameness is required, a video of the horse trotting directly towards the video camera at a minimum is recommended. Other video angles may provide supportive information regarding lameness characteristics.

Keywords: Lameness; Lameness locator; Telemedicine; Video.

© 2024. The Author(s).

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