Movement asymmetries in horses presented for prepurchase or lameness examination.

BACKGROUND: The increasing popularity of objective gait analysis makes application in prepurchase examinations (PPE) a logical next step. Therefore, there is a need to have more understanding of asymmetry during a PPE in horses described on clinical evaluation as subtly lame. OBJECTIVES: The objective of this study is to objectively compare asymmetry in horses raising minor vet concerns in a PPE and in horses raising major vet concerns with that found in horses presented with subtle single-limb lameness, and to investigate the effect of age/discipline on the clinicians' interpretation of asymmetry on the classification of minor vet concerns in a PPE. STUDY DESIGN: Clinical case-series. METHODS: Horses presented for PPE (n = 98) or subjectively evaluated as single limb low-grade (1-2/5) lame (n = 24, 13 forelimb lame, 11 hindlimb lame), from the patient population of a single clinic, were enrolled in the study provided that owners were willing to participate. Horses undergoing PPE were assigned a classification of having minor vet concerns (n = 84) or major vet concerns (n = 14) based on findings during the dynamic-orthopaedic part of the PPE. Lame horses were only included if pain-related lameness was confirmed by an objective improvement after diagnostic analgesia exceeding daily variation determined for equine symmetry parameters using optical motion capture. Clinical evaluation was performed by six different clinicians, each with ≥8 years of equine orthopaedic experience. Vertical movement symmetry was measured using optical motion capture, simultaneously with the orthopaedic examination. Data were analysed using previously described parameters and mixed model analysis and least squares means were used to calculate differences between groups. RESULTS: There was no effect of age or discipline on the levels of asymmetry within PPE horses raising minor vet concerns. MinDiff and RUD of the head discriminated between forelimb lame and PPE horses raising minor vet concerns; MinDiff, MaxDiff, RUD of the Pelvis, HHDswing and HHDstance did so for hindlimb lameness. Two lameness patterns differentiated both forelimb and hindlimb lame from PPE horses with minor vet concerns: RUD Poll + MinDiff Withers - RUD Pelvis and RUD Pelvis + RUD Poll - MinDiff Withers. Correcting for vertical range of motion enabled differentiation of PPE horses with minor vet concerns from PPE horses with major vet concerns. MAIN LIMITATIONS: Objective data only based on trot on soft surface, limited number of PPE horses with major vet concerns. CONCLUSIONS: Combinations of kinematic parameters discriminate between PPE horses with minor vet concerns and subtly lame horses, though overlap exists.

Visual lameness assessment in comparison to quantitative gait analysis data in horses.

BACKGROUND: Quantitative gait analysis offers objective information to support clinical decision-making during lameness workups including advantages in terms of documentation, communication, education, and avoidance of expectation bias. Nevertheless, hardly any data exist comparing outcome of subjective scoring with the output of objective gait analysis systems. OBJECTIVES: To investigate between- and within-veterinarian agreement on primary lame limb and lameness grade, and to determine relationships between subjective lameness grade and quantitative data, focusing on differences between (1) veterinarians, (2) live vs video assessment, (3) baseline assessment vs assessment following diagnostic analgesia. STUDY DESIGN: Clinical observational study. METHODS: Kinematic data were compared to subjective lameness assessment by clinicians with ≥8 years of orthopaedic experience. Subjective assessments and kinematic data for baseline trot-ups and response to 48 diagnostic analgesia interventions in 23 cases were included. Between and within-veterinarian agreement was investigated using Cohen's Kappa (κ). Asymmetry parameters for kinematic data ('forelimb lame pattern', 'hindlimb lame pattern', 'overall symmetry', 'vector sum head', 'pelvic sum') were determined, and used as outcome variables in mixed models; explanatory variables were subjective lameness grade and its interaction with (1) veterinarian, (2) live or video evaluation and (3) baseline or diagnostic analgesia assessment. RESULTS: Agreement on lame limb between live and video assessment was 'good' between and within veterinarians (median κ = 0.64 and κ = 0.53). There was a positive correlation between subjective scoring and measured asymmetry. The relationship between lameness grade and objective asymmetry differed slightly between (1) veterinarians (for all combined parameters, p-values between P < .001 and 0.04), (2) between live and video assessments ('forelimb lame pattern', 'overall symmetry', both P ≤ .001), and (3) between baseline and diagnostic analgesia assessment (all combined parameters, between P < .001 and .007). MAIN LIMITATIONS: Limited number of veterinarians (n = 4) and cases (n = 23), only straight-line soft surface data, different number of subjective assessments live vs from video. CONCLUSIONS: Overall, between- and within-veterinarian agreement on lame limb was 'good', whereas agreement on lameness grade was 'acceptable' to 'poor'. Quantitative data and subjective assessments correlated well, with minor though significant differences in the number of millimetres, equivalent to one lameness grade between veterinarians, and between assessment conditions. Differences between baseline assessment vs assessment following diagnostic analgesia suggest that addition of objective data can be beneficial to reduce expectation bias. The small differences between live and video assessments support the use of high-quality videos for documentation, communication, and education, thus, complementing objective gait analysis data.

Reliable and clinically applicable gait event classification using upper body motion in walking and trotting horses.

Objectively assessing horse movement symmetry as an adjunctive to the routine lameness evaluation is on the rise with several commercially available systems on the market. Prerequisites for quantifying such symmetries include knowledge of the gait and gait events, such as hoof to ground contact patterns over consecutive strides. Extracting this information in a robust and reliable way is essential to accurately calculate many kinematic variables commonly used in the field. In this study, optical motion capture was used to measure 222 horses of various breeds, performing a total of 82 664 steps in walk and trot under different conditions, including soft, hard and treadmill surfaces as well as moving on a straight line and in circles. Features were extracted from the pelvis and withers vertical movement and from pelvic rotations. The features were then used in a quadratic discriminant analysis to classify gait and to detect if the left/right hind limb was in contact with the ground on a step by step basis. The predictive model achieved 99.98% accuracy on the test data of 120 horses and 21 845 steps, all measured under clinical conditions. One of the benefits of the proposed method is that it does not require the use of limb kinematics making it especially suited for clinical applications where ease of use and minimal error intervention are a priority. Future research could investigate the extension of this functionality to classify other gaits and validating the use of the algorithm for inertial measurement units.

The Effect of Kinesiotape on Flexion-Extension of the Thoracolumbar Back in Horses at Trot.

Kinesiotape theoretically stimulates mechanoreceptive and proprioceptive sensory pathways that in turn may modulate the neuromuscular activity and locomotor function, so alteration of activation, locomotion and/or range of motion (ROM) can be achieved. The aim of this study was to determine whether kinesiotape applied to the abdominal muscles would affect the ROM in flexion-extension (sagittal plane) in the thoracolumbar back of horses at trot. The study design was a paired experimental study, with convenient sample. Each horse was randomly placed in the control or the intervention group and then the order reversed. Eight horses trotted at their own preferred speed in hand on a straight line, 2 × 30 m. Optical motion capture was used to collect kinematic data. Paired t-tests, normality tests and 1-Sample Wilcoxon test were used to assess the effects of the kinesiotape. No statistical significance (p < 0.05) for changes in flexion-extension of the thoracolumbar back in trot was shown in this group of horses. Some changes were shown indicating individual movement strategies in response to stimuli from the kinesiotape. More research in this popular and clinically used method is needed to fully understand the reacting mechanisms in horses.