[Kinetic and kinematic gait analysis of the back movement in chondrodystrophic breeds following hemilaminectomy in comparison to a healthy control population]. / Kinetische und Kinematische Gangbildanalyse der Rückenbewegung chondrodystropher Rassen nach Hemilaminektomie im Vergleich zu einer gesunden Population.

OBJECTIVE: To collect kinetic and kinematic data on the back movement in healthy dogs in comparison to chondrodystrophic dogs following hemilaminectomy while walking and trotting. MATERIAL AND METHODS: Gait analysis on the back movement was obtained from 19 healthy dogs and 21 chondrodystrophic dogs following hemilaminectomy procedure in consequence to disc herniation in the thoracic or lumbar region. RESULTS: In transverse and sagittal planes the group of surgically treated dogs showed a higher range of motion (ROM) throughout the spine while walking and trotting. The difference in back movement depended on the region of the hemilaminectomy (thoracic, thoracolumbar, or lumbar). Operated dogs showed a significantly higher weight distribution towards their front limbs. When comparing the weight distribution among the hind limbs, there was a decreased Peak Vertical Force (PVF) and Vertical Impulse (VI) on the side corresponding to the hemilaminectomy. CONCLUSIONS: Following hemilaminectomy, dogs displayed increased instability within their spine, which - depending on the region and side of the hemilaminectomy - affected the back movement in different ways. Weight bearing was generally shifted away from the hind limb of the affected side, and towards the front limbs. CLINICAL RELEVANCE: Even though hemilaminectomy has an effect on the back movement of dogs, it seems not to have relevant influence of quality of life.

Kinetic symmetry indices and standing gait analysis: A review of current methods and data.

Kinetic gait data is used to evaluate a dog's orthopedic soundness and to assess treatment response in clinical trials. It captures ground reaction forces (GRFs) generated by the interactions between an animal's limb and the ground and can be collected using force plates and pressure sensitive walkways. Historically, gait data were most commonly analyzed from a single, most clinically affected, limb evaluated while the dog walks or trots. More recently, symmetry indices, calculated using multiple methods, have been used to evaluate forces between paired limbs, as a method of evaluating multi-joint disease. However, when dogs are non-weight bearing lame (NWB) or have extreme mobility impairment, walking or trotting data can be difficult or impossible to collect. For these instances, standing gait analysis has been suggested as an option to collect non-zero data points. This review focuses on the reported methods of data collection for standing gait data, as well as methods of symmetry index calculation, and their use reported in the veterinary literature.

Development of a detailed canine gait analysis method for evaluating harnesses: A pilot study.

Dog harnesses are becoming more popular, with their large variety stemming from the idea that different dogs and scenarios require different types of harnesses. While their benefits over collars are self-explanatory, there is a lack of research on their effect on gait, and even the existing studies examine only a limited set of parameters. The goal of present study was to establish a method capable of quantifying canine gait in detail. Based on 3D motion capture, the developed method allows for the examination of 18 joint angles and 35 spatio-temporal parameters throughout multiple gait cycles, and can be used to analyze canine movement in detail in any kind of scenario (e.g. comparing healthy and lame dogs, or measuring the effect of training). The method is presented through the measurement of how different harnesses affect walking kinematics compared to free (unleashed) movements. Four dogs with varying body sizes and breeds and multiple types of harnesses were included. Marker data was filtered using a zero-lag 6th order Butterworth-filter with a cutoff frequency of 20 Hz. The normality of the spatio-temporal and joint range of motion parameters was tested using the Anderson-Darling test (p = 0.05), with most parameters passing in 60+% of test cases. Swing time and range of motion of the sagittal aspect of spinal angle at T1 vertebrae failed more regularly, both resulting from the measurement setup rather than the actual parameters being not normally distributed. Two-sample Kolmogorov-Smirnov tests (p = 0.05) were used to compare each parameter's distribution between cases, showing that most parameters are significantly altered by the harnesses in about 2/3rd of the cases. Based on the results, there's no absolute superior harness, however, it is possible to select the best fit for a specific dog and application, justifying their large variety.

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.

Altered Spatial and Temporal Gait Parameters in Mice Infected with Ross River Virus.

Infection with mosquito-borne arthritogenic alphaviruses, such as Ross River virus (RRV) and Barmah Forest virus (BFV), can lead to long-lasting rheumatic disease. Existing mouse models that recapitulate the disease signs and immunopathogenesis of acute RRV and BFV infection have consistently shown relevance to human disease. However, these mouse models, which chiefly model hindlimb dysfunction, may be prone to subjective interpretation when scoring disease. Assessment is therefore time-consuming and requires experienced users. The DigiGait system provides video-based measurements of movement, behavior, and gait dynamics in mice and small animals. Previous studies have shown DigiGait to be a reliable system to objectively quantify changes in gait in other models of pain and inflammation. Here, for the first time, we determine measurable differences in the gait of mice with infectious arthritis using the DigiGait system. Statistically significant differences in paw area and paw angle were detected during peak disease in RRV-infected mice. Significant differences in temporal gait parameters were also identified during the period of peak disease in RRV-infected mice. These trends were less obvious or absent in BFV-infected mice, which typically present with milder disease signs than RRV-infected mice. The DigiGait system therefore provides an objective model of variations in gait dynamics in mice acutely infected with RRV. DigiGait is likely to have further utility for murine models that develop severe forms of infectious arthritis resulting in hindlimb dysfunction like RRV. IMPORTANCE Mouse models that accurately replicate the immunopathogenesis and clinical disease of alphavirus infection are vital to the preclinical development of therapeutic strategies that target alphavirus infection and disease. Current models rely on subjective scoring made through experienced observation of infected mice. Here, we demonstrate how the DigiGait system, and interventions on mice to use this system, can make an efficient objective assessment of acute disease progression and changes in gait in alphavirus-infected mice. Our study highlights the importance of measuring gait parameters in the assessment of models of infectious arthritis.

Rater agreement for assessment of equine back mobility at walk and trot compared to quantitative gait analysis.

BACKGROUND: Lameness assessment in horses is still predominantly performed using subjective methods. Visual assessment is known to have moderate to good intra-rater agreement but relatively poor inter-rater agreement. Little is known about inter- and intra-rater agreement on the evaluation of back motion, for which no objective measurement technique in a clinical setting is available thus far. OBJECTIVES: To describe inter- and intra-rater agreement of visual evaluation of equine back mobility. STUDY DESIGN: Rater reliability study using a fully crossed design in which all horses are rated by all observers. This data is compared with objective gait analysis. METHODS: Seventy equine professionals (veterinarians and physiotherapists) and veterinary students evaluated videos of 12 healthy horses at walk and trot on a hard, straight line. Nine parameters related to back mobility were scored: general mobility, thoracic, lumbar, lumbosacral flexion and extension and left and right thoracolumbar latero-flexion. All parameters were compared with simultaneously measured quantitative motion parameters. After 1 month, six randomly chosen horses were re-evaluated by 57 observers. RESULTS: For each parameter inter- and intra-rater agreements were calculated using intra-class correlation coefficients. For all parameters, inter-rater agreement was very poor (<0.2). The mean intra-rater agreement of all observers and for all parameters was poor (~0.4) but varied between 0.0 and 0.96 for individual observers. There was no correlation between the visual subjective scoring and objective gait analysis measurements. MAIN LIMITATIONS: Horses were scored from videos and by lack of any existing (semi-) quantitative system, a custom-made system had to be used. CONCLUSIONS: The poor inter- and intra-rater agreements of visual scoring of mobility of the equine back and the disagreement between subjective and objective gait analysis data, demonstrate the need for the development and introduction of objective, quantitative and repeatable techniques to assess equine back motion.

Evaluation of Ground Reaction Forces and Limb Symmetry Indices Using Ground Reaction Forces Collected with One or Two Plates in Dogs Exhibiting a Stifle Lameness.

OBJECTIVE: The aim of the study was to evaluate the efficiency and consistency in the collection of ground reaction forces using one or two force plates from dogs with stifle lameness. ANIMALS: Twenty-two client-owned dogs with unilateral stifle lameness were used. METHODS: In a prospective study design, data were collected at a single time point using both one- and two-plate collection methods. Ground reaction forces collected included peak vertical force, vertical impulse and associated symmetry indices. Additionally, time required to obtain valid trials and the total number of trials were also recorded for both one-plate and two-plate collections. Linear mixed models were used to analyse differences in peak vertical force, vertical impulse and symmetry indices between the collection methods. A paired-T test was used to compare trial number and time of trial collection. The significance threshold was p < 0.05. RESULTS: It took significantly longer to collect valid trials using one-plate both in time (16.1 ± 8.0 minutes vs, 8.0 ± 4.3 minutes with two plates) and number of trials (33.8 ± 14.8 trials vs. 16.4 ± 8.8 trials with two plates) (p < 0.0001). There was no difference in peak vertical force or vertical impulse data between collection methods. Neither the peak vertical force symmetry indices nor the vertical impulse symmetry indices were significantly different between one- and two-plate collection techniques. CONCLUSION: The total time and number of trials needed to collect valid trials in dogs with stifle lameness were minimized through the use of two force plates. However, there was no significant difference in the ground reaction force or symmetry index values collected between the two systems.

The Effect of Calibration Method on Repeatability and Reproducibility of Pressure Mat Data in a Canine Population.

OBJECTIVE: The aim of this study was to investigate the repeatability and reproducibility of two different pressure-sensitive walkway calibration protocols, while collecting gait data from a heterogenous group of dogs. STUDY DESIGN: Fourteen dogs were walked across a high-definition pressure-sensitive walkway (Tekscan Strideway HRSW3) to obtain five valid trials from each dog. Two different calibration protocols were created following manufacturer recommendations: human step and phantom step using a custom-built three-legged device. Each calibration protocol was repeated five times, by three different operators, and then individually applied to the raw canine gait data. The software then automatically generated values for peak vertical force, vertical impulse and peak pressure for each trial. RESULTS: To control for the different bodyweight of the dogs, forces are reported as a percentage of bodyweight. Values for peak vertical force percentage of bodyweight, vertical impulse percentage of bodyweight and peak pressure were significantly different between calibration protocols, but the results were linearly correlated. Both calibration protocols were highly repeatable and highly reproducible. CONCLUSION: Both the step and phantom calibration protocols individually generated highly repeatable and reproducible results, which were not affected by different operators. A linear correlation was identified which may make it possible to apply a correction factor to enable comparison of results between different studies.

Horses fed meal contaminated with mycotoxins performing short-term exercises / Efeitos das micotoxinas na performance de equinos submetidos a exercícios de curta duração

This research was carried out to evaluate the effect of mycotoxins on the performance of horses through physiological parameters, and hematology and serum biochemistry analyses. The essay lasted 40 days, with 12 days for adaptation and 28 days of experimentation. In the experimental stage, the horses were distributed in a completely randomized design, with three treatments with four animals each. The treatments used were 0 (control), 50 ppb and 100 ppb of Aflatoxin B1 (AFB1) added to a concentrate in a basal diet. The basal diet contained mycotoxins from feedstuffs naturally contaminated. The exercise test was performed over the 21th day of the experimental stage. The exercise consisted in an interval training test with a warm-up of 17 mins at a trot followed by three gallops of 450m/min. The heart rate was monitored between the gallops. Before the exercise test and immediately after the third gallop, the physiological and blood parameters were evaluated, and continued up to 48 hours after the exercise. The results of the physiological, hematological and biochemical parameters were submitted to analysis of variance (ANOVA) and compared by the Tukey test at 5% of significance. The presence of AFB1 in the diet influenced the alkaline phosphatase activity, which presented higher values in horses fed diet with inclusion of 100 ppb AFB1, suggesting a hepatotoxic activity associated with the others mycotoxins naturally present in the feedstuffs.(AU)

Esta pesquisa foi conduzida para avaliar o efeito de micotoxinas no desempenho de equinos com avaliações fisiológicas e análises hematológicas e da bioquímica sérica. O ensaio durou 40 dias, com 12 dias de adaptação e 28 dias de experimentação. Na fase experimental, os equinos foram distribuídos em delineamento inteiramente casualizado em três tratamentos, com quatro animais cada. Os tratamentos utilizados foram 0 (controle), 50 ppb e 100 ppb de Aflatoxina B1 (AFB1) adicionada ao concentrado de uma dieta basal. A dieta basal continha alimentos naturalmente contaminados por micotoxinas. O teste de desempenho foi executado no 21º dia da fase experimental por meio de teste intervalado consistindo em aquecimento ao trote por 17 minutos, seguido de três galopes de 450m/min. A frequência cardíaca (FC) foi monitorada entre os galopes. Antes do exercício e imediatamente após o terceiro galope, os parâmetros fisiológicos e sanguíneos foram avaliados e continuaram sendo monitorados até 48 horas após o exercício. Os resultados dos parâmetros fisiológicos, hematológicos e bioquímicos foram submetidos à análise de variância (ANOVA) e comparados pelo teste de Tukey a 5% de significância. A presença de AFB1 na dieta influenciou a atividade da fosfatase alcalina, que apresentou valores mais elevadas na dieta com inclusão de 100 ppb de AFB1, sugerindo uma atividade hepatotóxica associada às outras micotoxinas naturalmente presentes nos alimentos.(AU)

Automatic hoof-on and -off detection in horses using hoof-mounted inertial measurement unit sensors.

For gait classification, hoof-on and hoof-off events are fundamental locomotion characteristics of interest. These events can be measured with inertial measurement units (IMUs) which measure the acceleration and angular velocity in three directions. The aim of this study was to present two algorithms for automatic detection of hoof-events from the acceleration and angular velocity signals measured by hoof-mounted IMUs in walk and trot on a hard surface. Seven Warmblood horses were equipped with two wireless IMUs, which were attached to the lateral wall of the right front (RF) and hind (RH) hooves. Horses were walked and trotted on a lead over a force plate for internal validation. The agreement between the algorithms for the acceleration and angular velocity signals with the force plate was evaluated by Bland Altman analysis and linear mixed model analysis. These analyses were performed for both hoof-on and hoof-off detection and for both algorithms separately. For the hoof-on detection, the angular velocity algorithm was the most accurate with an accuracy between 2.39 and 12.22 ms and a precision of around 13.80 ms, depending on gait and hoof. For hoof-off detection, the acceleration algorithm was the most accurate with an accuracy of 3.20 ms and precision of 6.39 ms, independent of gait and hoof. These algorithms look highly promising for gait classification purposes although the applicability of these algorithms should be investigated under different circumstances, such as different surfaces and different hoof trimming conditions.

Temporo-spatial and kinetic gait parameters in English setter dogs.

Walking analysis systems have begun to be used in veterinary medicine in recent years. The pressure-sensitive walkway is one of the systems through which we can obtain temporo-spatial and kinetic variables of walking. Therefore, the aim of this study was to investigate the walking characteristics of English Setter dogs using a pressure-sensitive system. Twenty-five English Setter dogs were included in the study. Temporo-spatial and kinetic gait parameters were obtained with the pressure-sensitive walkway system. Centre of pressure values were taken separately for the forelimbs and hindlimbs and were statistically analysed. The force values in the forelimb were found to be greater than in the hindlimb during walking. According to the results of dynamic pedobarographic evaluation, the highest-pressure values were found at the 2nd and 3rd digital pads for the forelimbs and on the 3rd and 4th digital pads for the hindlimbs. During the stance, 64.58% of the weight was found to be on the forelimbs. No difference was found between the forelimbs and the hindlimbs in centre of pressure analysis. As conclusion, the gait data obtained from the English Setter dogs can be used in future research to identify animals that may have neurological or orthopaedic problems.

Evaluation of a multibody kinematics optimization method for three-dimensional canine pelvic limb gait analysis.

BACKGROUND: Skin marker-based three-dimensional kinematic gait analysis were commonly used to assess the functional performance and movement biomechanics of the pelvic limb in dogs. Unfortunately, soft tissue artefact would compromise the accuracy of the reproduced pelvic limb kinematics. Multibody kinematics optimization framework was often employed to compensate the soft tissue artefact for a more accurate description of human joint kinematics, but its performance on the determination of canine pelvic limb skeletal kinematics has never been evaluated. This study aimed to evaluate a multibody kinematics optimization framework used for the determination of canine pelvic limb kinematics during gait by comparing its results to those obtained using computed tomography model-based fluoroscopy analysis. RESULTS: Eight clinically normal dogs were enrolled in the study. Fluoroscopy videos of the stifle joint and skin marker trajectories were acquired when the dogs walked on a treadmill. The pelvic limb kinematics were reconstructed through marker-based multibody kinematics optimization and single-body optimization. The reference kinematics data were derived via a model-based fluoroscopy analysis. The use of multibody kinematics optimization yielded a significantly more accurate estimation of flexion/extension of the hip and stifle joints than the use of single-body optimization. The accuracy of the joint model parameters and the weightings to individual markers both influenced the soft tissue artefact compensation capability. CONCLUSIONS: Multibody kinematics optimization designated for soft tissue artefact compensation was established and evaluated for its performance on canine gait analysis, which provided a further step in more accurately describing sagittal plane kinematics of the hip and stifle joints.

Force Plate Gait Analysis and Clinical Results after Tibial Plateau Levelling Osteotomy for Cranial Cruciate Ligament Rupture in Small Breed Dogs.

OBJECTIVE: The aim of this study was to evaluate objective limb function using force plate gait analysis after tibial plateau levelling osteotomy (TPLO) in small breed dogs with cranial cruciate ligament rupture (CCLR). MATERIALS AND METHODS: Small breed dogs (15 kg or less) with unilateral CCLR treated with TPLO were evaluated using symmetry index (SI) of peak vertical force (PVF), vertical impulse and vector magnitude at PVF performed preoperatively and at 1, 2, 4 and 6 months postoperatively after routine TPLO surgery. RESULTS: Twelve dogs met the inclusion criteria. Hindlimb function was markedly improved after TPLO, with all three postoperative SI significantly higher after a month than preoperative values (p < 0.01). At 2 months after surgery, the SI was nearly normalized to 1.0 (preoperative SI: 0.50 ± 0.20, 0.44 ± 0.19 and 0.51 ± 0.19, and 2 months postoperative SI: 0.92 ± 0.16, 0.90 ± 0.18 and 0.92 ± 0.16 respectively). Complications were noted in two dogs (fibular fracture and a partial implant failure), neither of which required a revision surgery for acceptable functional recovery. CONCLUSION: The objective limb function of the affected hindlimb improved continuously after surgery and reached a near normal value at 6 months after surgery. It was suggested that TPLO for small breed dogs had good outcomes based on force plate gait analysis.

Effect of induced hindlimb length difference on body-mounted inertial sensor measures used to evaluate hindlimb lameness in horses.

This study has investigated the immediate effect of induced hindlimb length difference on hindlimb lameness measured as differences in minimum (Pmin) and maximum (Pmax) pelvic heights in 16 horses trotting in a straight line and lungeing on both hard and soft surfaces with body-mounted inertial sensors. Hindlimb length differences were induced by applying an Easyboot Glue-on shoe to one hindlimb. Changes in Pmin and Pmax with induced hindlimb length difference were assessed with a two-way repeated-measures ANOVA with trial (straight, lunge with inside limb elevation, lunge with outside limb elevation) and surface (hard, soft) as within-subject factors. Change in Pmin, indicating an impact-type lameness, in the hind limb with the elevation, was significant in both the straight line and while lunging on both hard and soft surfaces. Change in Pmax, indicating pushoff-type lameness, in the opposite, non-elevated hind limb, was significant when trotting in a straight line but not while lunging.

OBJECTIVE GAIT ANALYSIS IN HUMBOLDT PENGUINS (SPHENISCUS HUMBOLDTI) USING A PRESSURE-SENSITIVE WALKWAY.

Assessment of pododermatitis, osteoarthritis, and other causes of lameness in penguins can be challenging. Subjective gait analysis using visual observation and response to analgesic therapy can be affected by observer variation and caregiver placebo bias. A pressure-sensitive walkway (PSW), however, allows for objective gait analysis and assessment of analgesic therapeutic response. In this study, a 3-m-long PSW was used to analyze gait in 21 adult Humboldt penguins (Spheniscus humboldti). Medical record reviews and comprehensive examinations were performed on all penguins; five penguins were considered abnormal, with either right-sided (n = 3) or bilateral historical lameness-causing disease (n = 2) and were analyzed separately from the normal data set. All penguins walked across the PSW four times and gait parameters (step and stride distances and velocities, maximum force, impulse, and peak pressure) were calculated for each foot in each penguin. Statistical comparisons were made between right and left feet, sexes, and normal and abnormal penguins for each gait parameter. Among normal penguins, there were no significant differences between feet or sex. Left step width was shorter in abnormal penguins than that of normal penguins. Study results established baseline values for Humboldt penguins. This will allow objective monitoring of progression and response to therapy in penguin lameness cases, both current and future. The data also provide a foundation to compare gait parameters with other penguin populations and species.

Use of a pressure-sensing walkway system for biometric assessment of gait characteristics in goats.

The purpose of this study was to quantitatively assess gait characteristics and weight-bearing forces during ambulation in goats free of lameness using a pressure-sensing walkway as a biometric tool for stride, gait, and force analysis. Forty-six non-lame adult goats ranging in age from 5 to 6 years, mixed-breeds, and with a mean body weight of 52 ± 7.1 kgs were used. Goats were trained to walk over a pressure-sensing walkway. Data for analysis was collected on 2 different days, 3 days apart. On each day, 2 to 5 walking passes, in the same direction, were captured for each goat. Data from 2 valid passes meeting the criteria for consistent walking gait on each day were averaged then used for analysis. Analysis was performed, including the day-effect, for stride, gait, and force characteristics. Of the 46 goats enrolled in the study, complete data sets were achieved in 33 (72%) goats. Gait biometrics were similar among the assessment days; therefore, all data was pooled for the purpose of characterizing data for individual limb and biometric parameter comparisons at the individual goat level. Statistical analysis revealed that no difference within the paired limbs, and that there were significant differences between the front limbs and hind limbs. Maximum force and maximum peak pressure were significantly greater for the front limbs as compared with the hind limbs (p < 0.001). Based on the results, gait and force characteristics can be consistently measured in goats using a pressure-sensing walkway during a consistent walking gait. Goats apply greater force to the forelimbs during the weight-bearing phase of stride as compared with the hind limbs. The use of objective assessment tools is expected to improve the ability of researchers and clinicians to monitor changes in weight bearing and gait and will contribute to improved animal welfare.

Evaluation of a pressure sensitive walkway for objective gait analysis in normal and arthritic domestic ducks (Cairina moschata domestica).

Objective gait evaluation with a pressure sensitive walkway (PSW) has been used to assess welfare of poultry and to assess lameness and response to therapy in domestic mammals. Objective gait analysis of birds with lameness due to pododermatitis, osteoarthritis, and other common diseases could provide non-biased assessment and therapeutic monitoring for zoo clinicians. The objective of this study was to evaluate the use of a PSW for objective gait analysis in normal domestic ducks (Cairina moschata domestica) and those with experimentally induced arthritis. Eighteen healthy adult ducks walked across the PSW four times in each experiment at each time point. For experiment 1, gait parameters (step and stride distances and velocities, maximum force, impulse, and peak pressure) were calculated for each foot in each duck (time 0). For experiment 2, six of these ducks were randomly selected, anesthetized, and administered a unilateral intra-tarsal injection of monosodium urate solution to induce arthritis. Serial PSW trials were repeated at 1, 2, 3, 4, 8, and 24 hours post-injection. Gait parameters were calculated and compared at each time point, including baseline at time 0. Among the normal ducks, there were no significant differences between right and left feet for any gait parameter. Maximum force and impulse were significantly lower for the affected limb at the 3- and 4-hour time points in ducks with unilateral induced arthritis. This asymmetry was resolved by 8 hours post injection. This PSW transient arthritis model allows for objective assessment of lameness in domestic ducks with maximum force and impulse serving as the most sensitive gait parameters for lameness detection. This method has potential as a model to assess analgesic efficacy for zoo-housed waterfowl and other avian species.

Evaluation of parameters obtained from two systems of gait analysis.

BACKGROUND: The technical difficulties in utilising the force platform have stimulated the use and development of other gait systems. Therefore, this study aimed to compare the values of gait parameters obtained from a pressure-sensitive walkway and from a treadmill in healthy dogs during walking. METHODS: Twelve healthy, privately owned, Labrador retriever dogs were used. During each trial, each dog was led across the pressure-sensitive walkway utilising a loose leash to the right of the handler. The velocity was restricted to the range of 0.9 to 1.1 m/s and the acceleration between -0.15 and 0.15 m/s2 . For the treadmill, each dog also walked with leash loose on the treadmill. The treadmill speed was maintained at 0.9m/s. The temporospatial variables, and percentage of body weight distribution/percentage of pressure were evaluated between the two gait systems. RESULTS: For both forelimbs and hind limbs, significant differences were found between stance percentage, which was higher on treadmill, and swing percentage and stride length/stance distance, which were higher on the pressure-sensitive walkway. The duty factor value was 0.57 for the pressure-sensitive walkway and 0.60 for treadmill. CLINICAL RELEVANCE: Each gait system has limitations, but also advantages that must be considered depending upon the variable and animal to be evaluated. The gait parameters obtained from the Tekscan pressure-sensitive walkway and Gait4Dog treadmill revealed differences in the temporospatial parameters between systems, but similarity in body-weight distribution/pressure percentage.

Evaluation of recovery of limb function by use of force plate gait analysis after tibial plateau leveling osteotomy for management of dogs with unilateral cranial cruciate ligament rupture.

OBJECTIVE: To evaluate recovery of limb function by use of gait force analysis after tibial plateau leveling osteotomy (TPLO) in dogs with unilateral cranial cruciate ligament (CrCL) rupture. ANIMALS: 19 dogs with unilateral CrCL rupture treated with TPLO. PROCEDURES: Force plate gait analysis was performed before and 1, 2, 4, and 7 months after TPLO. Ground reaction forces (GRFs; which comprised peak vertical force [PVF], vertical impulse [VI], peak braking force, braking impulse, peak propulsion force [PPF], and propulsion impulse), time to switching from braking to propulsion, and vector magnitude at PVF in the forelimbs and hind limbs were evaluated. RESULTS: GRFs in the affected hind limb were significantly lower than in the contralateral hind limb before TPLO. These variables, except for PPF, were not significantly different 7 months after TPLO. Time to the switching point in the affected hind limb was significantly less from before to 2 months after TPLO. Vector magnitude at PVF had a similar pattern as PVF and VI during the recovery process. The PVF in the ipsilateral forelimb was significantly higher than in the contralateral forelimb before TPLO. CONCLUSIONS AND CLINICAL RELEVANCE: A similar pattern was detected between PVF or VI and craniocaudal force during recovery of dogs that underwent TPLO. Rupture of he CrCl resulted in a decrease in GRFs in the affected hind limb as well as in the switching point and PVF of limbs. However, weight distribution for the craniocaudal force was normalized before PVF or VI. Vector magnitude at PVF might be effectively evaluated by combining vertical force and craniocaudal force.

Gait analysis in French bulldogs with and without vertebral kyphosis.

The study objective was to compare temporal-spatial and kinetic gait variables in neurologically normal French bulldogs with and without vertebral kyphosis. French bulldogs presented to a dedicated brachycephalic clinic were prospectively enrolled. All dogs underwent general physical, orthopaedic, and neurological examination prior to study inclusion. The presence of vertebral kyphosis was evaluated by computed tomography and kyphosis was defined as a Cobb angle exceeding 10°. Gait variables were collected using a pressure-sensitive GAITRite walkway with GAITFour software and included measurement of total pressure index (TPI) defined as the sum of peak pressure values recorded from each activated sensor by a paw during mat contact. Fifteen French bulldogs with (n=8) and without kyphosis (n=7) were included. Cobb angle in kyphotic dogs ranged from 14.9° to 39.5°. Univariate analyses were initially performed to examine the association between kyphosis and 16 gait variables. When those variables found to be associated (P<0.2) were taken forward into multivariate generalised linear mixed models (accounting for dog, velocity and side), kyphosis had a significant effect upon TPI of the forelimbs and TPI symmetry ratio (P<0.05); however, the size of these effects was small. Although vertebral kyphosis is rarely associated with neurological deficits, it was associated with subtle alterations in kinetic gait variables (TPI forelimbs and TPI symmetry ratio). Further studies are needed to evaluate the clinical importance of altered gait variables in French bulldogs with kyphosis.