Range of motion and between-measurement variation of spinal kinematics in sound horses at trot on the straight line and on the lunge. 

A.M. Hardeman, A. Byström, L. Roepstorff, J.H. Swagemakers, P.R. van Weeren, F.M. Serra Bragança

PLoS ONE 2020 12(2): e0222822

Abstract

Clinical assessment of spinal motion in horses is part of many routine clinical exams but remains highly subjective. A prerequisite for the quantification of spinal motion is the assessment of the expected normal range of motion and variability of back kinematics. The aim of this study was to objectively quantify spinal kinematics and between -measurement, -surface and -day variation in owner-sound horses. In an observational study, twelve owner-sound horses were trotted 12 times on four different paths (hard/soft straight line, soft lunge left and right). Measurements were divided over three days, with five repetitions on day one and two, and two repetitions on day three (recheck) which occurred 28-55 days later. Optical motion capture was used to collect kinematic data. Elements of the outcome were: 1) Ranges of Motion (ROM) with confidence intervals per path and surface, 2) a variability model to calculate between-measurement variation and test the effect of time, surface and path, 3) intraclass correlation coefficients (ICC) to determine repeatability. ROM was lowest on the hard straight line. Cervical lateral bending was doubled on the left compared to the right lunge. Mean variation for the flexion-extension and lateral bending of the whole back were 0.8 and 1 degrees. Pelvic motion showed a variation of 1.0 (pitch), 0.7 (yaw) and 1.3 (roll) degrees. For these five parameters, a tendency for more variation on the hard surface and reduced variation with increased repetitions was observed. More variation was seen on the recheck (p<0.001). ICC values for  pelvic  rotations were between 0.76 and 0.93, for the whole back flexion-extension and lateral bending between 0.51 and 0.91. Between-horse variation was substantially higher than within-horse variation. In conclusion, ROM and variation in spinal biomechanics are horse-specific and small, necessitating individual analysis and making subjective and objective clinical assessment of spinal kinematics challenging.

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

C. Ericson, P. Stenfeldt, A.M. Hardeman, I. Jacobsen

Animals 2020, 10 (2), 301

Abstract

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.

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Variation in gait parameters used for objective lameness assessment in sound horses at the trot on the straight line and the lunge. 

A.M. Hardeman, F.M. Serra Bragança, J.H.Swagemakers, P.R. van Weeren, L. Roepstorff

Equine Veterinary Journal 0 (2019) 1-9

Summary 

Background: Objective lameness assessment is gaining more importance in a clinical setting, necessitating availability of reference values.
Objectives: To investigate the between -path, -trial and -day variation, between and within horses, in the locomotion symmetry of horses in regular use that are perceived sound.
Study design: Observational study with replicated measurement sessions
Methods: Twelve owner-sound horses were trotted on the straight line and on the lunge. Kinematic data were collected from these horses using 3D optical motion capture. Examinations were repeated on 12 occasions over the study which lasted 42 days in total. For each horse, measurements were grouped as 5 replicates  on the first and second measurement days and two replicates on the third measurement day.  Between measurement days 2 and 3, every horse had a break from examination of at least 28 days. Previously described symmetry parameters were calculated: RUD and RDD (Range Up/Down Difference; difference in upward/downward movement between right and left halves of a stride; MinDiff and MaxDiff (difference between the two minima/maxima of the movement; HHDswing and HHDstance (Hip Hike Difference-swing/-stance; difference between the upward movement of the tuber coxae during swingphase/stancephase). Data are described by the between-measurement-variation for each parameter. A linear mixed model was used to test for the effect of time, surface and path. Intraclass correlation coefficients (ICC) were calculated to access repeatability.
Results: Mean between-measurement-variation was (MinDiff, MaxDiff, RUD, RDD): 13mm, 12mm, 20mm, 16mm (head); 4mm, 3mm, 6mm, 4mm (withers) and 5mm, 4mm, 6mm, 6mm (pelvis); (HHDswing, HHDstance): 7 and 7mm. 
More between-measurement-variation is seen on the first measurement day compared to the second and third measurement days. In general, less variation is seen with increasing number of repetitions.
Less between-measurement-variation is seen on hard surface compared to soft surface. More between-measurement-variation is seen on the circle compared to the straight line. Between-horse variation was clearly larger than within-horse variation. ICC values for the head, withers and pelvis symmetry parameters were 0.68 (head), 0.76 (withers), 0.85 (pelvis). 
Main limitations: Lunge measurements on a hard surface were not performed.
Conclusions: Between-measurement-variation may be substantial, especially in head motion. This should be considered when interpreting clinical data after repeated measurements, as in routine lameness assessments.

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

C. Roepstorff, M.T. Dittmann, S. Arpagaus, F.M. Serra Bragança, A.M. Hardeman, E. Persson-Sjödin, L. Roepstorff, A. Imogen Gmel, M.A. Weishaupt

Journal of Biomechanics 2021 (114) 110146

Abstract

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.

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Vertical movement symmetry of the withers in horses with naturally occurring forelimb and hindlimb lameness at trot

E. Persson-Sjödin, E. Hernlund, T. Pfau, P. Haubro Andersen, K. Holm Forsström, A. Byström, F.M. Serra Bragança,  A.M. Hardeman, L. Greve, A. Egenvall, M. Rhodin

Manuscript

Abstract

The most prominent compensatory asymmetry is the head nod down in horses with a primary hindlimb lameness. A possible clinical pitfall is mistaking this for primary ipsilateral forelimb lameness, which might delay correct diagnosis. The objective of this study was to describe compensatory lameness patterns and to examine whether the relationship between the direction of head and withers movement asymmetry parameters can be used to distinguish horses with primary forelimb lameness from horses with a compensatory head movement asymmetry due to primary hindlimb lameness. Medical records and objective movement symmetry data, collected with high-speed cameras as part
of routine lameness investigations at four different locations, were retrospectively analysed. Head, withers and pelvis motion asymmetries in 241 horses trotting in a straight line were compared before and after successful diagnostic analgesia was performed on one limb. Linear models and paired t-tests were used to analyse the data. In horses with forelimb lameness, 78-83% showed ipsilateral head-withers asymmetry. In horses
with hindlimb lameness, 90% showed diagonal pelvis-withers asymmetry. In 27-33% of the hindlimb lame horses, a large ipsilateral head movement asymmetry was seen, while 82-83% of these horses still showed diagonal pelvis-withers asymmetry and thus contralateral head-withers asymmetry. This study demonstrates that head and withers movement asymmetry parameters generally indicate
the same forelimb in horses with forelimb lameness and indicate opposite forelimbs in horses with hindlimb lameness. Quantification of withers asymmetry is therefore a useful supplement in clinical objective lameness assessment and could help locate the primary lameness in hindlimb lame horses with a compensatory ipsilateral head movement asymmetry.

Differences in equine spinal kinematics between straight line and circle in trot

A. Byström, A.M. Hardeman, F.M. Serra Bragança, L. Roepstorff, J.H. Swagemakers, P.R. van Weeren, A. Egenvall

Manuscript

Abstract

Work on curved tracks, e.g. on circles, is commonplace within all forms of horse training. Horse movements on a circle are naturally asymmetric, including the load distribution between inner and outer limbs. Within equestrian dressage the horse is expected to bend the back laterally to follow the circle, but this has never been studied scientifically. In the current study 12 horses were measured (optical motion capture, 100 Hz) trotting on the left and right circles and on straight line without rider (soft surface). Data from markers placed along the spine indicated increased lateral bending to the inside (e.g. left on the left circle) of the thoracolumbar back (left -3.75°; right 3.61° vs. straight) and the neck (left -5.23°; right 4.80°). Lateral bending ROM increased on the circle (0.87° and 0.62°). Individual variation in straight-circle differences were evident, but each horse was generally consistent over multiple trials. Differences in back movements between circle and straight were generally small and may or may not be visible, but accompanying changes in muscle activity and limb movements may add to the visual impression.

Movement asymmetries in horses presented for pre purchase or lameness examination

A.M. Hardeman, A. Egenvall, F.M. Serra Bragança, M.H.W. Koene, J.H. Swagemakers, L. Roepstorff, P.R. van Weeren, A. Byström

Manuscript

Summary 

Background: The increasing popularity of objective gait analysis in equine clinical orthopaedics makes application for gait assessment in pre purchase examinations (PPE) a logical next step. To put outcome in perspective, it is useful to compare the subjectively accepted degree of asymmetry during a PPE with horses clinically qualified as subtly lame. 
Objectives: To objectively compare horses receiving a positive (PPE-positive) and negative (PPE-negative) advice after PPE with subtly lame horses, and to investigate the possibly confounding effect of age and discipline on the subjectively accepted asymmetry during a PPE.
Study design: Observational study
Methods: Kinematics of 98 PPE and 24 (1-2/5) lame horses were analysed using previously described parameters; MinDiff/MaxDiff (difference between the two minima/maxima of one stride) and RUD/RDD (Range Up/Down Difference; difference in upward/downward movement between right and left halves of a stride) of head, withers and pelvis and HHDswing/HHDstance (difference between the upward movement of the tuber coxae during swing/stance phase). Mixed model analysis and least squares means were used to calculate differences between groups. 
Results: There was no effect of age or discipline within the PPE-positive group. MinDiff and RUD of the head discriminated between forelimb lame and PPE-positive horses; MinDiff, MaxDiff, RUD of the Pelvis, HHDswing and HHDstance did so for hindlimb lameness. Two lameness patterns  differentiated both fore- and hindlimb lame from PPE-positive horses: RUD Poll + MinDiff Withers- RUD Pelvis and RUD Pelvis + RUD Poll – MinDiff Withers. Correcting for vertical range of motion improved the first formula, enabling differentiation of PPE-positive from PPE-negative horses. 
Main limitations: Objective data only based on trot on soft surface, limited number of PPE-negative horses.
Conclusions: Combinations of kinematic parameters discriminate between PPE-positive and subtly lame horses, though overlap exists. A big data approach may improve the discriminative power of the presented models.

Visual lameness assessment including the effect of diagnostic analgesia in comparison to quantitative gait analysis outcome

A.M. Hardeman, A. Egenvall, F.M. Serra Bragança, J.H. Swagemakers, M.H.W. Koene, L. Roepstorff, P.R. van Weeren, A. Byström

Manuscript

Summary

Background: Quantitative gait analysis offers objective information, which can support clinical decision-making during lameness work-up. This study compares kinematic data to subjective assessment by experienced clinicians. 
Objectives: To investigate between- and within-veterinarian agreement on determining the primary lame limb, lameness grade and improvement following diagnostic analgesia (“block”), and to correlate subjective grading of lameness and evaluation of diagnostic analgesia to quantitative data, including differences in live versus video assessment, and baseline versus assessment following diagnostic analgesia.
Study design: Observational study
Methods: Subjective assessment of 48 blocks was related to kinematic data, using MinDiff/MaxDiff/RUD of Head, Withers and Pelvis (differences between vertical minimum/maximum/upward movement of right and left halves of a stride), HHDswing/HHDstance (difference between upward movement of the tuber coxae during swing/stance phase), and combined patterns; ‘forelimb lame pattern’, ‘hindlimb lame pattern’, ‘fit-to-compete score’, ‘Vector Sum Head’, ‘Pelvic Sum’. Differences between veterinarians, between live versus video, and between assessments of blocks versus baseline were investigated using Cohen’s Kappa (κ) indices and linear mixed models.
Results: Agreement on lame limb, (between-veterinarian during live and video assessment and within-veterinarian) was ‘good’ with κ=0.64, κ=0.58, and κ=0.53. The linear relationship between subjective scoring and measured asymmetry was moderately good. There were similar overall correlations 1) between veterinarians, 2) for live versus video, and 3) for baseline versus block assessment.
Main limitations: Limited number of veterinarians(n=4)/horses(n=23), only straight-line soft surface data, different number of datapoints for live versus video evaluation. 
Conclusions: Overall, agreement was good between and within veterinarians. Similar correlations between quantitative data and subjective assessment were found, with small differences between veterinarians, for live versus video, and for baseline versus assessment following diagnostic analgesia. It is concluded that quantitative gait analysis may have added value in providing unbiased information supporting clinical decision-making, for educating clinicians and as reliable documentation.
 

Interpretation of objective gait analyses, including a comparison to subjective evaluation of lameness in horses.

A.M. Hardeman, A. Byström, A. Egenvall, F.M. Serra Bragança, J.H. Swagemakers, L. Roepstorff, P.R. van Weeren

Manuscript

Abstract

Despite routine application of quantitative gait analysis in the equine practice nowadays, there is no guideline on the clinical interpretation of the objective data. The objectives of this study were therefore to investigate agreement between objective and subjective evaluation on the primary lame limb and to provide clinicians with guidelines on how to interpret their clinical data, based on scientific literature. Twenty-three horses, presented to the clinic for lameness evaluation and subjectively assessed as 1,2 or 3/5 (AAEP scale) single limb lame by one of the four participating veterinarians, were trotted on the straight line and on the lunge. Kinematic data were collected using 3D optical motion capture. Horses were evaluated subjectively, both live and on video assessment. A thorough interpretation of the objective data was performed and outcome was compared to the subjective assessment. Good agreement was achieved between subjective assessment and evaluation of the objective data. A structured overview of argumentation was obtained, which may serve as a guideline for clinicians to interpret their objective data. Main limitations were the limited number of participating horses and the fact that data were only collected on soft surface.

Pros and cons of quantitative gait analysis in the commercial equine clinic
A survey under current users and non-users on expectances, experiences and opinions

A.M. Hardeman, P.R. van Weeren, F.M. Serra Bragança, H. Warmerdam, H.G.J. Bok

Manuscript

Summary

Background: Objective gait analysis is rapidly gaining ground in equine orthopaedic practice. Pros and cons are discussed within scientific literature, however, no general data exist on the appreciation of objective gait analysis by equine orthopaedic clinicians, their motivation to use or not this technology and their perception of its usability in daily practice.
Objectives: To make an inventory of opinions, expectances and experiences of current users and non-users of objective gait analysis in commercial equine practice. 
Study design: Survey.
Methods: A questionnaire about objective gait analysis was sent out to equine orthopaedic clinicians in commercial practice. Respondents were classified as user or non-user (with versus without clinical experience with objective gait analysis). Data were analysed using descriptive statistics. 
Results. Many more users than non-users belonged to the highest experience category of >10 years of orthopaedic practice (72.5% versus 44.8%). Users were more positive about the usefulness of objective gait analysis than non-users. A minority of users (17.5%) and non-users (12.5%) deemed objective gait analysis also suitable for others than veterinarians. Users who purchased a system were motivated by better objectivity, transparency, documentation and client service. Main reasons not to purchase a system were costs and complexity of data interpretation.
Main limitations: Users outnumbered non-users (n=40 versus n=32), which is not representative for equine clinicians worldwide. Sample size was limited (n=72) and insufficient to separate results per gait analysis system. 
Conclusions: More experienced clinicians also see added value in objective gait analysis systems. Apart from the price, the complexity of data interpretation and a lack of practical and technical support are major factors in the decision not to buy a system. The first conclusion underpins the value of the objective systems, the second points at the principal area in which progress needs to be made to improve clinical practicality.