Radiographic assessment of carpal conformation in the horse: Technique development and validation of the consistency of measurements

Abstract

Carpal conformation is often considered as a contributory factor to performance and lameness in the horse; however, few attempts have been made to objectively measure radiographic variations of carpal conformation in horses due to insufficient measurable carpal parameters. This pilot study used carpal radiographic images acquired from 10 cadaveric equine forelimbs transected at the antebrachial midshaft from 7 adult horses (7.2 ± 2.6 years), positioned at ‘zero lateromedial’ (ZLM) and ‘zero dorsopalmar’ (ZDP) views, to investigate the anatomy of the equine carpus and develop parameters that could be objectively used to assess carpal conformation in horses. Dorsal carpal angle (DCA: 176.61 ± 0.66º), distal radial slope carpal angle (DRSCA: 145.59 ± 2.19º), intermediate carpal bone proximal tuberosity‐radial angle (CiPxTRA: 115.69 ± 3.15º) and third carpal bone palmar facet angle (C3PalFCA: 84.43 ± 1.13º) were all developed from the ZLM view while medial carpal angle (MCA: 183.34 ± 1.02º), disto‐dorsal slope angle of the third carpal bone (C3DDSA: 8.27 ± 0.92º) and width ratio of distal radius to proximal metacarpus (WDR:WPM = 1.13±0.03) were 3 of the 10 parameters developed from the ZDP view. Easy to identify and measurable parameters will help to provide quantitative assessment of carpal conformation in the horse with potential of eliminating subjective observational variation errors between clinicians. These newly developed parameters will be useful in further studies to measure variations in the conformation of the equine carpus in live horses and comparison between subjective visual assessment and objective radiographic evaluation methods.

Clinical and Radiological Evaluation of Distal Extremity Lesions in Racehorses

“…The structure of the forelimb in horses is critical for the horse's overall athletic performance and susceptibility to lameness, as it carries approximately 55-60% of the body weight of a standing horse. During races or strenuous exercise, the front extremities are exposed to more stress than the rear [3,7,8]. In this study, 85% of the horses had lesions in various parts of the forelimbs (n=119), whereas 15% had lesions in various parts of the rear limbs (n=21).…”

Radiographic assessment of carpal conformation in the horse, part 2: Finding acceptable limits to postural and rotational variations during radiography

“…A custom‐built compression frame for the equine limb (Altrib, 2013) previously used in part one of the study (Olusa et al., 2020) was also used for the current study (Figure 2a).…”

“…All the 14 carpal parameters were measured from the acquired radiographs as previously described (Olusa, 2018; Olusa et al., 2020). Below is the list of 4 ZLM parameters and 10 ZDP developed on ZLM and ZDP radiographs, respectively.…”

“…All the 14 carpal parameters were measured from the acquired radiographs as previously described (Olusa, 2018;Olusa et al, 2020). The Bonferroni-adjusted t tests were used to compare mean effects between levels with a significant difference.…”

“…Development and validation of measurable radiographic parameters for the carpal joint in the standing horse (Olusa, 2018; Olusa et al., 2020) should therefore involve testing the potential effects of these postural tilts and rotational variations of X‐ray beam and plates on carpal measurements if the developed parameters are to be useful for routine clinical and field application.…”