Comparison of pressure plate and force plate gait kinetics in sound Warmbloods at walk and trot

Prediction of continuous and discrete kinetic parameters in horses from inertial measurement units data using recurrent artificial neural networks

Vertical ground reaction force (GRFz) measurements are the best tool for assessing horses' weight-bearing lameness. However, collection of these data is often impractical for clinical use. This study evaluates GRFz predicted using data from body-mounted IMUs and long short-term memory recurrent neural networks (LSTM-RNN). Twenty-four clinically sound horses, equipped with IMUs on the upper-body (UB) and each limb, walked and trotted on a GRFz measuring treadmill (TiF). Both systems were time-synchronised. Data from randomly selected 16, 4, and 4 horses formed training, validation, and test datasets, respectively. LSTM-RNN with different input sets (All, Limbs, UB, Sacrum, or Withers) were trained to predict GRFz curves or peak-GRFz. Our models could predict GRFz shapes at both gaits with RMSE below 0.40 N.kg^-1. The best peak-GRFz values were obtained when extracted from the predicted curves by the all dataset. For both GRFz curves and peak-GRFz values, predictions made with the All or UB datasets were systematically better than with the Limbs dataset, showing the importance of including upper-body kinematic information for kinetic parameters predictions. More data should be gathered to confirm the usability of LSTM-RNN for GRFz predictions, as they highly depend on factors like speed, gait, and the presence of weight-bearing lameness.

Technology applications in bovine gait analysis: A scoping review

Quantitative bovine gait analysis using technology has evolved significantly over the last two decades. However, subjective methods of gait assessment using visual locomotion scoring remain the primary on-farm and experimental approach. The objective of this review is to map research trends in quantitative bovine gait analysis and to explore the technologies that have been utilized to measure biomechanical parameters of gait. A scoping literature review was conducted according to PRISMA guidelines. A search algorithm based on PICO framework generated three components-bovine, gait, and technology-to address our objectives. Three online databases were searched for original work published from January 2000 to June 2020. A two-step screening process was then conducted, starting with the review of article titles and abstracts based on inclusion criteria. A remaining 125 articles then underwent a full-text assessment, resulting in 82 final articles. Thematic analysis of research aims resulted in four major themes among the studies: gait/claw biomechanics, lameness detection, intervention/comparison, and system development. Of the 4 themes, lameness detection (55% of studies) was the most common reason for technology use. Within the literature identified three main technologies were used: force and pressure platforms (FPP), vision-based systems (VB), and accelerometers. FPP were the first and most popular technologies to evaluate bovine gait and were used in 58.5% of studies. They include force platforms, pressure mapping systems, and weight distribution platforms. The second most applied technology was VB (34.1% of studies), which predominately consists of video analysis and image processing systems. Accelerometers, another technological method to measure gait characteristics, were used in 14.6% of studies. In sum, the strong demand for automatic lameness detection influenced the path of development for quantitative gait analysis technologies. Among emergent technologies, deep learning and wearable sensors (e.g., accelerometers) appear to be the most promising options. However, although progress has been made, more research is needed to develop more accurate, practical, and user-friendly technologies.

Effects of jump height on forelimb landing forces in border collies

Objective

The objective of this study was to evaluate the effects of jump height on the landing forces of dogs.

Animals

Client-owned Border Collies experienced in agility competition, n = 9.

Procedures

The study involved client owned border collies with the same AKC standard jump height of 20 inches and preferred height of 16 inches. Standard height is based upon the height of the dog at the withers, with preferred height referred to as reduction in jump height by one level due to injury or age. An AKC regulation bar jump was placed over a previously validated pressure sensitive walkway (PSW). The peak force (%BW) and peak contact pressure (kPa) of the leading and trailing forelimbs were evaluated for all dogs.

Results

There was no significant difference in landing force between the two jump heights for either peak force as a percentage of body weight or peak contact pressure when evaluated in both leading and trailing forelimbs.

Conclusions and clinical relevance

Our findings demonstrated no significant difference in active landing forces of peak contact pressure and peak force on the forelimbs of dogs when jumping at a standard jump height vs. a preferred jump height when controlling for velocity in dogs performing a single running bar jump. These results suggest that the recommendation of decreasing jump height for older animals or injured animals may not provide a significant decrease in the impact on the forelimbs. It is likely that other factors contribute to the total forelimb kinematics picture during competition. Veterinarians and trainers should consider additional ways to decrease impact for canine athletes as they recover from injury.

Artificial Intelligence for Lameness Detection in Horses-A Preliminary Study

Lameness in horses is a long-known issue influencing the welfare, as well as the use, of a horse. Nevertheless, the detection and classification of lameness mainly occurs on a subjective basis by the owner and the veterinarian. The aim of this study was the development of a lameness detection system based on pose estimation, which permits non-invasive and easily applicable gait analysis. The use of 58 reference points on easily detectable anatomical landmarks offers various possibilities for gait evaluation using a simple setup. For this study, three groups of horses were used: one training group, one analysis group of fore and hindlimb lame horses and a control group of sound horses. The first group was used to train the network; afterwards, horses with and without lameness were evaluated. The results show that forelimb lameness can be detected by visualising the trajectories of the reference points on the head and both forelimbs. In hindlimb lameness, the stifle showed promising results as a reference point, whereas the tuber coxae were deemed unsuitable as a reference point. The study presents a feasible application of pose estimation for lameness detection, but further development using a larger dataset is essential.

Bilateral Change in Vertical Hoof Force Distribution in Horses with Unilateral Forelimb Lameness before and after Successful Diagnostic Anaesthesia

Kinetic examinations of horses with induced lameness as well as the effect of perineural anaesthesia in sound horses have shown promise, but clinical studies regarding the effect of diagnostic anaesthesia during the different stance phases are rare. Fourteen horses with unilateral forelimb lameness were examined with the Hoof™ System during trot to assess vertical force distribution (in kg) affecting both front hooves before and after diagnostic anaesthesia during landing, midstance, and breakover. For statistical analysis, a covariance analysis with repeated measurements regarding the limb (lame/sound) as well as anaesthesia (before/after) and the covariable body weight was performed. The p-values for the pairwise comparisons were adjusted using the Bonferroni−Holm correction (p < 0.05). For all phases of the stance, a significant interaction between the factors limb and anaesthesia was shown. Before diagnostic anaesthesia, vertical force was significantly reduced on the lame limb compared to the sound limb during landing (−25%, p < 0.001), midstance (−20%, p < 0.001) and breakover (−27%, p < 0.001). After anaesthesia, the difference between both forelimbs was not significant anymore for all phases. The vertical force on the lame limb increased significantly after positive anaesthesia during the whole stance phase, with breakover being most affected (+27%, p = 0.001). Pressure measurements with the Hoof™ System can be used to evaluate the effect of diagnostic anaesthesia in a clinical setting with pain-related vertical force asymmetries being neutralised after diagnostic anaesthesia. Breakover is the main event influenced by lameness.

Rabbit hindlimb kinematics and ground contact kinetics during the stance phase of gait

Though the rabbit is a common animal model in musculoskeletal research, there are very limited data reported on healthy rabbit biomechanics. Our objective was to quantify the normative hindlimb biomechanics (kinematics and kinetics) of six New Zealand White rabbits (three male, three female) during the stance phase of gait. We measured biomechanics by synchronously recording sagittal plane motion and ground contact pressure using a video camera and pressure-sensitive mat, respectively. Both foot angle (i.e., angle between foot and ground) and ankle angle curves were unimodal. The maximum ankle dorsiflexion angle was 66.4 ± 13.4° (mean ± standard deviation across rabbits) and occurred at 38% stance, while the maximum ankle plantarflexion angle was 137.2 ± 4.8° at toe-off (neutral ankle angle = 90 degrees). Minimum and maximum foot angles were 17.2 ± 6.3° at 10% stance and 123.3 ± 3.6° at toe-off, respectively. The maximum peak plantar pressure and plantar contact area were 21.7 ± 4.6% BW/cm2 and 7.4 ± 0.8 cm2 respectively. The maximum net vertical ground reaction force and vertical impulse, averaged across rabbits, were 44.0 ± 10.6% BW and 10.9 ± 3.7% BW∙s, respectively. Stance duration (0.40 ± 0.15 s) was statistically significantly correlated (p < 0.05) with vertical impulse (Spearman's ρ = 0.76), minimum foot angle (ρ = -0.58), plantar contact length (ρ = 0.52), maximum foot angle (ρ = 0.41), and minimum foot angle (ρ = -0.30). Our study confirmed that rabbits exhibit a digitigrade gait pattern during locomotion. Future studies can reference our data to quantify the extent to which clinical interventions affect rabbit biomechanics.

Use of a protective cover affects ground reaction force measurements obtained from dogs walking on a validated pressure-sensitive walkway

OBJECTIVE

To determine whether use of a protective cover would affect temporospatial gait or ground reaction force (GRF) measurements obtained from dogs walking on a validated pressure-sensitive walkway (PSW).

ANIMALS

5 healthy dogs.

PROCEDURES

In a crossover study design, all dogs were walked across a calibrated PSW with and without a protective cover in place in random order. Temporospatial gait data and GRFs obtained with and without the cover in place were compared.

RESULTS

No significant differences were identified in temporospatial gait measurements obtained with versus without the cover in place. The bias was low for all variables, and the 95% limits of agreement included 0. In contrast, significant differences were found between measurements obtained with versus without the cover in place for most GRFs, with measurements obtained with the cover in place significantly lower than those obtained without a cover.

CLINICAL RELEVANCE

Results suggested that for dogs walking over a PSW, GRFs, but not temporospatial gait variables, would be significantly lower if a protective cover was placed over the walkway, compared with values obtained without a cover in place.

Mechanical Principles of the Equine Foot

A healthy foot requires a well-balanced foot capable of shock absorption, traction, and normal proprioception. Radiographs and venograms are helpful in assessing health of the external and internal structures of the foot and in early diagnosis. Other techniques to assess foot mechanics include force plate and inertial sensors. When foot pathology ensues, early recognition and emergency mechanical treatment can improve prognosis and overall outcome. Sheared heels, under-run heels, and clubfeet are common problems that need to be corrected early. Successful management and results require he veterinarians and farriers establishing a professional, collaborative, and respectful relationship.

Autologous protein solution: a promising solution for osteoarthritis?

Osteoarthritis (OA) is a global health issue with myriad pathophysiological factors and is one of the most common causes of chronic disability in adults due to pain and altered joint function.

The end stage of OA develops from a destructive inflammatory cycle, driven by the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumour necrosis factor alpha (TNFα).

Owing to the less predictable results of total knee arthroplasty (TKA) in younger patients presenting with knee OA, there has been a surge in research evaluating less invasive biological treatment options, one of which is autologous protein solution (APS).

APS is an autologous blood derivative obtained by using a proprietary device, made of APS separator, which isolates white blood cells (WBCs) and platelets in a small volume of plasma, and APS concentrator, which further concentrates platelets, WBCs and plasma proteins, resulting in a concentrated solution with high levels of growth factors including the anti-inflammatory mediators against IL-1β and TNFα.

A single intraarticular injection of APS appears to be a promising solution for treatment of early-stage OA from current evidence, the majority of which comes from preclinical studies.

More clinical studies are needed before APS can be widely accepted as a treatment modality for OA.

Cite this article: EFORT Open Rev 2021;6:716-726. DOI: 10.1302/2058-5241.6.200040

Equine hindlimb hoof biomechanics: an evaluation of the effect of routine hoof trimming on force and pressure distribution at midstance

Proper hoof function is vital for equine health and performance. Many musculoskeletal injuries in horses originate from the foot. Most studies performed to date have focused on the forehoof while the hindhoof (HH) has received less attention. Our goal was to examine the influence of routine hoof trimming on HH medio-lateral hoof balance. The objective of this study was to examine force (F), contact pressure (CP), and contact area (CA) at the medial and lateral aspects of the HH to evaluate the impact of routine hoof trimming on HH biomechanics. Clinically sound Arabian horses (n=9) were walked across a calibrated pressure plate before and after routine hoof trimming and the F, CP, and CA at the medial and lateral aspects of the HH were recorded at midstance pre- and post-trimming. The differences between these regions were investigated using a paired T-test. P-values <0.05 were considered significant. Among measured variables, force increased by 25% (P=0.007) and contact pressure increased by 13% (P=0.032) at the medial aspect of the HH after routine hoof trimming. Analysing data from hindlimb hoof-surface interaction in sound horses will allow for a better understanding of imbalances that may lead to pathologies and hindlimb lameness in horses.

Intra-Articular Umbilical Cord Derived Mesenchymal Stem Cell Therapy for Chronic Elbow Osteoarthritis in Dogs: A Double-Blinded, Placebo-Controlled Clinical Trial

Background: Intra-articular stem cell therapy may help alleviate lameness caused by osteoarthritis in dogs. Umbilical cord-derived stem cell (UMSC) therapy has not yet been investigated in a veterinary clinical study. We hypothesized that dogs treated with intra-articular UMSC will have improved limb function and quality of life when compared to dogs treated with a saline placebo injection. Methods: This was a prospective, double-blinded, placebo-controlled clinical trial in client-owned dogs with chronic elbow osteoarthritis with a follow-up time of 6 months. Dogs were assigned to receive intra-articular UMSC (n = 38) or a saline placebo intra-articular injection (n = 30). Outcome measures included the Canine Brief Pain Inventory score (CBPI) and peak vertical force (PVF) from force-platform gait analysis. Treatment was considered successful when there was a decrease in the Pain Severity Score of at least one and a decrease in the Pain Interference Score of at least one from baseline. Success rates and PVF were compared between groups. Results: No adverse effects associated with UMSC were noted. Of the dogs completing the study, treatment success in the UMSC (n = 28) vs. placebo groups (n = 23) was observed in 54 vs. 28% of dogs at 1 month, 50 vs. 27% at 3 months, and 46 vs. 14% at 6 months, respectively. Success rate in the UMSC group was significantly higher than the placebo group at 1 and 6 months after treatment. However, no differences in PVF of the affected limb over time was observed in either group. Conclusions: Intra-articular UMSC for osteoarthritis may improve clinical signs based on owner observations.

The effect of routine hoof trimming on midstance regional hoof kinetics at walk

There is a lack of objective and quality evidence-based research on the effect of trimming on hoof loading at different regions of the hoof. Our objective was to measure and compare force (F), contact area (CA), contact pressure (CP) and peak contact pressure (PCP) of the dorsal vs palmar and medial vs lateral regions of the forehooves. Nine sound equine athletes were walked across a calibrated pressure plate before and after routine hoof trimming. The F, CA, CP and PCP in medial, lateral, dorsal and palmar regions were examined pre- and post-trimming, P≤0.05 was considered significant. Dorsal CP and PCP significantly increased post-trimming (P=0.039 and P=0.019, respectively). Medial F increased about 25% after trimming, but not significantly (P=0.129). These data confirm the impact of individual hoof trimming on certain aspects of the hoof midstance biomechanics.

Ground Reaction Forces: The Sine Qua Non of Legged Locomotion

Legged locomotion results from the feet pressing against the ground to generate ground reaction forces (GRFs) that are responsible for moving the body. By changing limb coordination patterns and muscle forces, the GRFs are adjusted to allow the horse to move in different gaits, speeds, and directions with appropriate balance and self-carriage. This article describes the typical GRF patterns in each gait, the adaptations that produce turning, and the GRF patterns used to unload the painful limb when the horse is lame. The intent is to provide information that is of practical interest and value to equine scientists rather than being a comprehensive review of the topic.

Changes in hoof kinetics and kinematics at walk in response to hoof trimming: pressure plate assessment

Appropriate hoof preparation and symmetry are linked to the well-being of the horse. Previous studies have shown the efficacy of pressure plates (PPs) in delivering objective biomechanical analysis. We aimed to assess the effect of hoof trimming on hoof biomechanics using a PP. Nine clinically sound Arabian horses were walked across a PP while foot strike was recorded by a digital camera. Kinetic and kinematic parameters were recorded before and after trimming. Changes were considered significant when p < 0.05. Vertical force (p = 0.026) and contact pressure (p = 0.006) increased after trimming. Stance-phase duration (p = 0.006), swing-phase duration (p = 0.023), and gait-cycle duration (p = 0.007) decreased significantly post-trimming. The observed changes in kinetic and kinematic parameters were related to hoof trimming. The reported results underline the importance of farriery practice and its effect on hoof biomechanics, which should be considered by both farriers and veterinarians.

Assessment of static posturography and pedobarography for the detection of unilateral forelimb lameness in ponies

BACKGROUND

Static posturography and pedobarography are based on the detection of postural imbalance and, consequently, the pressure redistribution between limbs in lame subjects. These techniques have proven to be useful for the detection of lameness in humans and dogs. The main objective of this study was to test the suitability of static posturography and pedobarography in diagnosing lameness in ponies. A pressure platform was used to obtain postural data (statokinesiograms, mean X and Y, length, LFS ratio, and mean velocity) from 10 sound ponies and 7 ponies with unilateral forelimb lameness. Static pedobarographic data (pressure distribution, mean pressure, and peak pressure) were also collected and compared with force plate data (peak vertical force and vertical impulse) obtained from the same animals at the walk.

RESULTS

Significant differences were seen between lame and sound ponies for almost all evaluated parameters. With this sample size, differences between lame and sound limbs/groups were detected with a statistical power of 90%, except for mean X and Y.

CONCLUSIONS

Static posturography and pedobarography provide a complementary approach for lameness detection in equids.

Predicting Lameness in Sheep Activity Using Tri-Axial Acceleration Signals

Simple Summary

Monitoring livestock farmed under extensive conditions is challenging and this is particularly difficult when observing animal behaviour at an individual level. Lameness is a disease symptom that has traditionally relied on visual inspection to detect those animals with an abnormal walking pattern. More recently, accelerometer sensors have been used in other livestock industries to detect lame animals. These devices are able to record changes in activity intensity, allowing us to differentiate between a grazing, walking, and resting animal. Using these on-animal sensors, grazing, standing, walking, and lame walking were accurately detected from an ear attached sensor. With further development, this classification algorithm could be linked with an automatic livestock monitoring system to provide real time information on individual health status, something that is practically not possible under current extensive livestock production systems.

Abstract

Lameness is a clinical symptom associated with a number of sheep diseases around the world, having adverse effects on weight gain, fertility, and lamb birth weight, and increasing the risk of secondary diseases. Current methods to identify lame animals rely on labour intensive visual inspection. The aim of this current study was to determine the ability of a collar, leg, and ear attached tri-axial accelerometer to discriminate between sound and lame gait movement in sheep. Data were separated into 10 s mutually exclusive behaviour epochs and subjected to Quadratic Discriminant Analysis (QDA). Initial analysis showed the high misclassification of lame grazing events with sound grazing and standing from all deployment modes. The final classification model, which included lame walking and all sound activity classes, yielded a prediction accuracy for lame locomotion of 82%, 35%, and 87% for the ear, collar, and leg deployments, respectively. Misclassification of sound walking with lame walking within the leg accelerometer dataset highlights the superiority of an ear mode of attachment for the classification of lame gait characteristics based on time series accelerometer data.

Analysis of peak plantar pressure and center of pressure oscillation in individuals with chronic neck pain: A cross-sectional study

BACKGROUND

Baropodometric evaluation has been used in research and clinical environments by professionals who are working on the physical rehabilitation of patients. However, to date, there is no published data on the use of baropodometry in patients with chronic neck pain.

OBJECTIVE

To analyze peak plantar pressure and center of pressure oscillation in individuals with chronic neck pain compared to a control group.

METHODS

This was a blind cross-sectional study. It included 44 participants of both genders, between 18 and 45 years old, distributed into a chronic neck pain group (n= 22) and a control group (n= 22). Participants were assessed by means of baropodometry, the Numeric Rating Scale, the Neck Disability Index, and the Pain-Related Self Statement Scale. The Mann-Whitney test was used for comparison of baropodometric variables between the two groups, and the Spearman correlation coefficient was used to check possible associations between the variables.

RESULTS

No significant differences (p> 0.05) in peak plantar pressure or center of pressure oscillation were detected in the comparisons between the chronic neck pain and control groups. In addition, no significant correlation was observed (p> 0.05) between baropodometric variables and neck pain.

CONCLUSION

Individuals with chronic neck pain with mild disability did not differ from a control group in terms of peak plantar pressure or center of pressure oscillation.

The development of locomotor kinetics in the foal and the effect of osteochondrosis

Reason for performing study

Foals stand and walk immediately after birth, but insight into the subsequent longitudinal development of their gait kinetics in the early juvenile phase and the possible influence of osteochondrosis thereon is lacking.

Objectives

To quantify gait kinetics in foals during the first half year of life, taking into account their osteochondrosis status.

Study design

Prospective, cohort study performed at a single stud farm.

Methods

Pressure plate measurements at walk and trot from 11 Dutch Warmblood foals during the first 24 weeks of life were used to determine body mass normalised peak vertical force, normalised vertical impulse and stance duration. Coefficients of variation of peak vertical force and stance duration were used as measures for gait maturity. Radiographs of tarsocrural and femoropatellar joints were taken at age 4–6 weeks and after 6 months to check for osteochondrosis. A linear mixed model was used to determine the effects of age, limb, presence of osteochondrosis and speed on gait parameters.

Results

Mean walking and trotting velocity increased over time as did stance duration and normalised vertical impulse, normalised peak vertical force values however remained relatively constant. During the first weeks of their life only the coefficient of variation of stance duration decreased significantly, while the coefficient of variation of peak vertical force did not. None of the foals was visibly lame, but the presence of osteochondrosis resulted in a temporarily but significantly reduced normalised peak vertical force.

Main limitations

This study is a relatively small sample size of one breed from a single stud farm. A stand‐alone pressure plate was used and body mass was estimated rather than measured.

Conclusions

Despite being precocious, foals need time to mature their gait. During growth, velocity at walk and trot increases, but normalised peak vertical force remains relatively constant. Although not visibly lame, a temporary reduction in normalised peak vertical force was detected in osteochondrosis positive foals using a pressure plate.

Clinical effects of buprenorphine on open field behaviour and gait symmetry in healthy and lame weaned piglets

Lameness in pigs decreases animal welfare and economic profit for the farmer. An important reason for impaired welfare in lame animals is pain due to lameness. No direct measurement of pain is possible in animals, and methods to indirectly detect and quantify the amount of pain an animal is experiencing are urgently needed. In this study, two methods to assess pain associated with lameness in pigs were evaluated to determine if they were sensitive enough to detect a lameness reduction as an effect of an experimental analgesic medication. Asymmetry associated with lameness was objectively quantified using pressure mat kinetic parameters: peak vertical force (PVF), load rate (LR), vertical impulse (VI) and peak vertical pressure (PVP). Locomotor activity was assessed in an open field test. A dose of 0.04 mg/kg buprenorphine, a strong analgesic, was used to treat 10 lame pigs, while eight other lame pigs, treated with physiological saline solution, served as controls. Buprenorphine decreased lameness-associated asymmetry for pressure mat LR (P = 0.002), VI (P = 0.003) and PVP (P = 0.001) and increased activity of the lame pigs in the open field (P = 0.023), while saline-treated animals did not show any changes in asymmetry and became less active in the open field (P <0.001). It was concluded that measurement of gait asymmetry by pressure mat analysis and locomotor activity in an open field test are both sensitive enough to detect the analgesic effects of buprenorphine when used to treat moderate to severe clinical pain in a relatively small group of affected pigs. The methods used in this study may also provide promising additional tools for future research into early pain recognition and lameness treatment in pigs.

Predicting Complete Ground Reaction Forces and Moments During Gait With Insole Plantar Pressure Information Using a Wavelet Neural Network

In general, three-dimensional ground reaction forces (GRFs) and ground reaction moments (GRMs) that occur during human gait are measured using a force plate, which are expensive and have spatial limitations. Therefore, we proposed a prediction model for GRFs and GRMs, which only uses plantar pressure information measured from insole pressure sensors with a wavelet neural network (WNN) and principal component analysis-mutual information (PCA-MI). For this, the prediction model estimated GRFs and GRMs with three different gait speeds (slow, normal, and fast groups) and healthy/pathological gait patterns (healthy and adolescent idiopathic scoliosis (AIS) groups). Model performance was validated using correlation coefficients (r) and the normalized root mean square error (NRMSE%) and was compared to the prediction accuracy of the previous methods using the same dataset. As a result, the performance of the GRF and GRM prediction model proposed in this study (slow group: r = 0.840-0.989 and NRMSE% = 10.693-15.894%; normal group: r = 0.847-0.988 and NRMSE% = 10.920-19.216%; fast group: r = 0.823-0.953 and NRMSE% = 12.009-20.182%; healthy group: r = 0.836-0.976 and NRMSE% = 12.920-18.088%; and AIS group: r = 0.917-0.993 and NRMSE% = 7.914-15.671%) was better than that of the prediction models suggested in previous studies for every group and component (p < 0.05 or 0.01). The results indicated that the proposed model has improved performance compared to previous prediction models.

Influence of calibration protocols for a pressure-sensing walkway on kinetic and temporospatial parameters

OBJECTIVES

To evaluate the influence on the kinetic and temporospatial parameters of calibration protocols with point and step techniques for a pressure-sensing walkway.

METHODS

Nine Labrador dogs were used. Two protocols of point calibration technique (C1 and C2) and eight protocols of step calibration technique (C3 to C10) were performed. In C1, weight was added to a stool to match the body mass of each dog. In C2, weight was added to the stool to match a 46.1 kg person. The other eight calibration protocols represented combinations of the following factors: 46.1 kg and 96.1 kg persons, barefoot or wearing sneakers, and stepping onto the platform with one or two feet.

RESULTS

The calibration protocols did not affect the temporospatial variables or percentages of body weight (%BW) distribution. Significant differences were found in both PVI (peak vertical force) and VI (vertical impulse) between barefoot versus wearing sneakers, 46.1 kg versus 96.1 kg person, and stepping onto the platform with one foot versus two feet. When comparing C1 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs. When comparing C2 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs in all protocols.

CLINICAL SIGNIFICANCE

The PVF and VI were influenced by the calibration protocol used, but the %BW distribution and temporospatial parameters were not. Using the same calibration protocol for all dogs within the same group eliminated the variability of the kinetic data caused by the calibration.

A comparison of ground reaction forces during level and cross-slope walking in Labrador Retrievers

Background

Inclined or slippery surfaces and various other types of obstacles are common demands in our environment. Dogs with impaired locomotion might have difficulties to manage rough terrain. Gait analyses using force plates or pressure plates, which are well established to characterize limb loads in human medicine as well as in animals, are mostly limited to level surfaces. Therefore, the aim of this study was to investigate the effect of cross-slope walking in ten healthy Labrador Retrievers using a pressure plate walkway system. The dogs walked over the pressure plate on a level surface, with a lateral elevation angle of 10° (CS1) or 15° (CS2) until five valid trials were achieved. Three measurements were obtained at weekly intervals. Peak vertical force (PFz), vertical impulse (IFz), step length, and velocity were determined.

Results

Compared to level walking (LW), cross-slope walking was associated with a significant decrease in GRF of the up-slope (US) hindlimb, which was compensated for by the down-slope (DS) forelimb. The other diagonal limb pair showed less pronounced effects during CS1, but in CS2 more weight was shifted onto the DS hindlimb during the first two measurements, thus reducing weight on the US forelimb (for IFz). The effect diminished from trial to trial, with GRF values approaching LW standards finally. The IFz was a more sensitive measure than the PFz. The step length of the DS forelimb was significantly decreased in both cross-slope conditions, while the step length of the US forelimb only decreased during CS2.

Conclusions

The dogs adapted their gait pattern and step length to compensate for the discrepancy in apparent leg length caused by the cross-slope. The results suggest that cross-slope walking requires functional musculoskeletal adaptations that may be difficult for animals with impaired locomotion. Further, this knowledge might be of clinical impact for early diagnosis of neurological disorders, mild lameness and proprioceptive deficits.

Pressure mat analysis of the longitudinal development of pig locomotion in growing pigs after weaning

BACKGROUND

Gait evaluation is difficult in pigs, especially when objective and quantitative data are needed, thus little research has been conducted in this species. There is considerable experience, however, with objective gait analysis in other species, such as horses and dogs. In this study, a pressure mat was used to establish baseline kinetic data for gait and its longitudinal development in growing, weaned piglets.Ten clinically healthy weaned piglets were trained to trot over a pressure mat. Measurements were performed weekly during 10 weeks, starting at 5 weeks of age. Four kinetic parameters were recorded for all four limbs: peak vertical force (PVF), load rate (LR), vertical impulse (VI) and peak vertical pressure (PVP). Three representative runs per measuring session per pig were collected. For each of the variables, left vs. right limb asymmetry-indices (ASI's) were calculated based on the average for that parameter per week. A linear mixed model was used to determine the influence of time (week), velocity, and limb (left vs. right, and fore vs. hind). Intra-class correlations were calculated to assess within-session replicability.

RESULTS

Intra-class correlations showed good within-session replicability. Body-weight normalized PVF (nPVF), LR (nLR), VI (nVI) and PVP (nPVP) were higher in the forelimbs than in the hind limbs. A higher velocity was associated with a higher nPVF, nLR and nPVP. All parameters varied between weeks. ASI of LR and VI were higher in the forelimbs than in the hind limbs. Velocity and time did not influence ASI of any of the variables.

CONCLUSIONS

Kinetic pressure mat measurements from healthy weaned piglets are highly replicable within-session. However, these variables present a significant variability between-session, which may be due to conformational changes of the young, growing piglets. Velocity clearly influences nPVF, nLR and nPVP, and all kinetic variables have higher values in forelimbs than in hind limbs. As time and velocity do not affect ASI's, the latter are preferable tools when velocity cannot be controlled or when measurements are repeated over longer time intervals. The present study supports the use of a pressure mat as an objective way to analyze and quantify porcine gait.

Pressure plate analysis of toe-heel and medio-lateral hoof balance at the walk and trot in sound sport horses

Empirically, equine distal limb lameness is often linked to hoof imbalance. To objectively quantify dynamic toe-heel and medio-lateral hoof balance of the vertical ground reaction force in sound sport horses, seven Royal Dutch Sport Horses were led at the walk and trot over a dynamically calibrated pressure plate. Forelimb hoof prints were divided into a toe and heel region and a medial and lateral zone. Toe-heel and medio-lateral hoof balance of the vertical ground reaction force were calculated throughout the stance. Toe-heel balance was highly symmetrical between contralateral limbs at both gaits. At the walk, medio-lateral balance of both forelimbs presented higher loading in the lateral part of the hoof throughout the stance. However, at the trot, left medio-lateral balance presented higher loading of the medial part of the hoof at impact, whereas the right limb showed higher loading of the lateral part of the hoof in all horses, and both limbs presented increased lateral loading at the end of the stance. This study provides objective data for toe-heel and medio-lateral hoof balance in sound sport horses.

Effect of Clostridium botulinum toxin type A injections into the deep digital flexor muscle on the range of motion of the metacarpus and carpus, and the force distribution underneath the hooves, of sound horses at the walk

In the treatment of laminitis, reducing deep digital flexor muscle (DDFM) activity might diminish its pull on the distal phalanx, thereby preventing displacement and providing pain relief. Injection of Clostridium botulinum toxin type A into the DDFM of horses is potentially therapeutic. However, the effects of C. botulinum toxin type A on the gait characteristics of sound horses at the walk are not known. The aim of this study was to test if a reduced DDFM activity would lead to (1) alterations of the sagittal range of motion of the metacarpus (SROM) and range of motion of the carpal joint (CROM); (2) changes in the force distribution underneath the hoof (toe vs. heel region: balance index); and (3) changes in the force distribution between the treated and untreated limb (symmetry index). The DDFMs of the left forelimbs of seven sound Royal Dutch Sport Horses were injected with 200 IU C. botulinum toxin type A using electromyography and ultrasound guidance. Measurements using an inertial sensor system and dynamically calibrated pressure plate were performed before and after injections. The SROM and CROM of the treated limb were significantly increased after C. botulinum toxin type A injections. No significant changes were detected in the balance index or in the symmetry index, indicating that no lameness was induced. C. botulinum toxin type A injections into the DDFM of sound horses do not appear to result in substantial gait alterations at the walk.

Kinetic and temporospatial parameters in male and female cats walking over a pressure sensing walkway

BACKGROUND

Several factors may influence kinetic data measurements, including body conformation and body mass. In addition, gender differences in gait pattern have been observed in healthy humans. Therefore, the aim of this study was to compare the kinetic and temporospatial parameters in clinically healthy male and female cats using a pressure-sensitive walkway. Eighteen crossbreed adult cats were divided into two groups: G1 had ten male cats (nine neutered) aged from 1 to 4 years and body mass 3.1-6.8 kg; G2 had eight spayed female cats, aged from 1 to 6 years and body mass 3.3-4.75 kg. The data from the first five valid trials were collected for each cat. A trial was considered valid if the cat maintained a velocity between 0.54-0.74 m/s and acceleration from -0.20 to 0.20 m/s2. The peak vertical force (PVF), vertical impulse (VI), gait cycle time, stance time, swing time, stride length, and percentage body weight distribution among the four limbs were determined. In addition, the lengths of each forelimb and each hind limb were measured using a tape with the animal standing.

RESULTS

No significant differences were observed in each group in either the forelimbs or the hind limbs or between the left and right sides for any of the variables. For both groups, the PVF (%BW), the VI, and the percentage body weight distribution were higher at the forelimbs than the hind limbs. The stride length was larger for males; however, the other kinetic and temporospatial variables did not show any statistically significant differences between the groups. The lengths of the forelimbs and hind limbs were larger in the male cats. There was a significant moderate positive correlation between the stride length and the length of the limbs.

CONCLUSIONS

In conclusion, the only difference observed between male and female cats was the stride length, and this was due to the greater body size of male cats. This difference did not affect other temporospatial or kinetics variables.

Gait analysis in clinically healthy sheep from three different age groups using a pressure-sensitive walkway

BACKGROUND

Understanding normal gait requires allowing for variations in normal patterns by the sex, age, and species in question. Therefore, the aim of this study was to evaluate kinetic and temporospatial parameters in clinically healthy sheep from three different age groups with a pressure-sensing walkway. The sheep were judged to be healthy based on the results of complete physical and orthopaedic examinations and had no history of lameness. Twenty-one clinically healthy female Santa Ines sheep were divided into three groups: G1 - seven animals, aged from 8 to 12 months and weighing 19.5-33 kg; G2 - seven individuals, aged from 2 to 4 years and weighing 26.5-42 kg; and G3 - seven sheep, aged more than 5 years and weighing 37.3-45 kg. The animals were examined from two directions: first on the left side and then on the right side of the handler. The data from the first five valid trials in each direction were collected for each sheep and analysed using the designated software. A trial was considered valid if the sheep walked within the correct velocity (1.1-1.3 m/s) and acceleration (from -0.15 to 0.15 m/s2) ranges. The peak vertical force (PVF), vertical impulse (VI), gait cycle time, stance time, swing time, stride length, and the percentage body weight distribution among the four limbs were determined.

RESULTS

No significant differences were observed, in either the forelimbs or the hind limbs, between the left and right sides or between the two directions for any of the variables. No significant temporospatial differences were found among the groups. Significant PVF (%BW) differences were observed in the forelimbs (G1>G3) and hind limbs (G1>G3), and significant VI differences were observed in the forelimbs (G1>G3).

CONCLUSIONS

Young healthy sheep differ from older sheep in the vertical forces they create when walking at the same velocity on a pressure-sensing walkway.

Accuracy of pressure plate kinetic asymmetry indices and their correlation with visual gait assessment scores in lame and nonlame dogs

OBJECTIVE

To determine the accuracy of pressure plate kinetic asymmetry indices (ASIs) for diagnosis of unilateral hind limb lameness in dogs and their correlation with visual gait assessment (VGA) scores.

ANIMALS

9 healthy dogs and 16 dogs with previously diagnosed unilateral rupture of the cranial cruciate ligament and concurrent unilateral hind limb lameness.

PROCEDURES

Dogs were walked over a pressure plate to determine paw contact area (PCA), peak vertical pressure (PVP), peak vertical force (PVF), and vertical impulse (VI) of both hind limbs. An ASI was calculated for each gait variable. Simultaneously, gait was assessed visually and scored by use of a numeric rating scale (0 to 10). The ASI of each variable was tested for its usefulness in discrimination between lame and nonlame dogs and for correlation with VGA scores.

RESULTS

Sensitivity and specificity of ASIs to discriminate between lame and nonlame dogs were excellent for PVF, VI, and PCA; these values were substantially lower for ASI of PVP. Cutoff values to discriminate between lame and nonlame dogs were determined by use of ASIs for PVF, VI, and PCA; however, this could not be done for ASI of PVP. Correlations between ASIs of PVF, VI, and PCA and VGA scores were higher than correlation between the ASIs of PVP and VGA scores.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that ASIs of PVF and VI determined via analysis of pressure plate measurements were reliable indicators of clinical lameness in dogs, but the ASI of PVP was not. The ASI of PCA is an interesting new variable for assessment of limb loading symmetry.

Intraarticular injection of hyaluronan prevents cartilage erosion, periarticular fibrosis and mechanical allodynia and normalizes stance time in murine knee osteoarthritis

Introduction

Intraarticular hyaluronan (HA) is used clinically for symptomatic relief in patients with knee osteoarthritis (OA); however, the mechanism of action is unclear. In this study, we examined the effects of a single injection of HA on joint tissue pathology, mechanical allodynia and gait changes (measured by stride times) in a murine model of OA.

Methods

OA was induced in the right knee joint (stifle) of 12-week-old male C57BL/6 mice by transforming growth factor β1 (TGFβ1) injection and treadmill running for 14 days. Gait parameters were quantified by using TreadScan, mechanical allodynia was evaluated with von Frey filaments, and joint pathology was evaluated by scoring of macroscopic images for both cartilage erosion and periarticular fibrosis. HA or saline control was injected 1 day after TGFβ1 injection but before the start of treadmill running.

Results

OA development in this model was accompanied by significant (P < 0.01) enhancement of the stance and propulsion times of affected legs. HA injection (but not saline injection) blocked all gait changes and also protected joints from femoral cartilage erosion as well as tibial and femoral tissue fibrosis. Both HA injection and saline injection attenuated acute allodynia, but the HA effect was more pronounced and prolonged than the saline injection.

Conclusions

We conclude that videographic gait analysis is an objective, sensitive and reproducible means of monitoring joint pathology in experimental murine OA, since stance time appears to correlate directly with OA severity. A single injection of HA prevents acute and prolonged gait changes and ameliorates the cartilage erosion and periarticular fibrosis normally seen in this model. We speculate that the capacity of HA to prevent cartilage erosion results from its normalization of joint biomechanics and its inhibitory effects on periarticular cells, which are involved in tissue hyperplasia and fibrosis. This effect of exogenous HA appears to mimic the protective effects of ablation of Adamts5 (a disintegrin and metalloproteinase with thrombospondin motifs 5) on experimental murine OA, and we speculate that a common mechanism is involved.