Influence of borderline hip dysplasia on joint kinematics of clinically sound Belgian Shepherd dogs

An update on mobility assessment of dogs with musculoskeletal disease

Mobility impairments associated with musculoskeletal diseases, such as osteoarthritis and degenerative joint disease, affect approximately 200,000 dogs annually and pose a notable challenge to canine health and welfare. Osteoarthritis causes the remodelling of synovial joints, alongside inflammation and impaired mechanical function which can be extremely debilitating. Secondary osteoarthritis commonly affects dogs and can be exacerbated by previous joint abnormalities, such as patellar luxation or cranial cruciate ligament rupture. Although musculoskeletal diseases can affect dogs of any age, the early subtle signs of gait abnormalities are perhaps missed by owners, thus, dogs may be in the latter stages of osteoarthritis progression when they are presented to veterinarians. Dogs showing subtle signs of gait abnormalities must be presented to veterinary practices for acute diagnosis to prevent long-term deterioration. Musculoskeletal diseases, such as osteoarthritis and degenerative joint disease, are commonly diagnosed via visible radiographic changes. However, veterinarians can use a combination of subjective and objective clinical scoring systems, such as clinical metrology instruments and gait assessment in conjunction with radiography to aid their diagnosis and longitudinal monitoring of musculoskeletal diseases. These scoring systems may be more sensitive to earlier signs of mobility impairments in dogs, ultimately, promoting increased canine health and welfare by enabling pain reduction, improvement of muscle strength and preservation of joint function. Current canine mobility scoring systems available to veterinarians will be discussed in turn throughout this review for implementation into clinical practice.

Quantification of phenobarbital-induced ataxia in dogs with idiopathic epilepsy

Ataxia is a clinical sign seen in several neurological diseases and has been reported as an adverse effect of anti-seizure medication such as phenobarbital (PB). Efforts to objectify canine ataxia in order to provide appropriate treatment or monitor adverse effects of drugs remain limited. Automated quantitative gait analysis can be useful for the acquisition of objective data for the evaluation and monitoring of ataxia in dogs. The aim of this prospective clinical study was to examine the gait characteristics of dogs with PB induced ataxia and compare them with healthy dogs using a computer- and treadmill-based gait analysis system. Six healthy dogs and five dogs with idiopathic epilepsy (IE) with PB-induced ataxia underwent video- and computer-assisted gait analysis during slow walking (maximum speed of 0.7 m/s) on a treadmill with four ground reaction force plates (one plate per limb). Kinetic and spatio-temporal gait parameters of dogs' locomotion were analyzed, including individually calculated coefficients of variation. Dogs with IE treated with PB showed higher variability in spatio-temporal but not in kinetic gait parameters. Double support phase of gait cycles was increased on the cost of single support and swing phases. Body weight standardized ground reaction forces in vertical, craniocaudal, and mediolateral direction were severely affected by ataxia. Compensatory mechanisms in locomotion of dogs with PB-induced ataxia included spatio-temporal and kinetic gait characteristics, most likely in order to compensate imbalance caused by limb incoordination.

Thermography as a tool to assess training effects in military working dogs

Military working dogs are exposed to high levels of physical load during their work, although this is not always evident from their behaviour. This workload causes various physiological changes, including variation in the temperature of the affected body parts. In this preliminary study, we investigated whether thermal changes following the daily work routine of military dogs are detectable by infrared thermography (IRT). The experiment was carried out on eight male German and Belgian shepherd patrol guard dogs performing two training activities, obedience and defence. The surface temperature (Ts) of 12 selected body parts on both body sides was measured with the IRT camera 5 min before, 5 min after and 30 min after training. As predicted, there was a greater increase in Ts (mean of all measured body parts) after defence than after obedience, 5 min (by 1.24 vs. 0.60 °C, P < 0.001) and 30 min after activity (by 0.90vs. 0.57 °C, P < 0.01) compared to pre-activity levels. These findings indicate that defence is more physically demanding than obedience activity. Considering the activities separately, obedience increased Ts 5 min after the activity only in the trunk (P < 0.001) but not in the limbs, whereas defence increased it in all measured body parts (P < 0.001). Ts 30 min after obedience decreased to the pre-activity level in parts at trunk, while in distal parts of the limbs Ts remained elevated. The prolonged elevation in Ts of the limbs after both activities indicates heat flow from the core to the periphery as a thermoregulatory mechanism. The current study suggests that IRT may be a useful tool for assessing physical workload in different body parts of dogs.

Comparison of Canine Forelimb Kinematic Joint Angles Collected with 2D and 3D Models

OBJECTIVE

 The aim of this study was to compare a Joint Coordinate System (JCS) three-dimensional (3D) kinematic model of the canine forelimb with more widely used linear (LIN) and segmental (SEG) 2D models.

STUDY DESIGN

 It was an in vivo biomechanical study.

ANIMALS

 Normal adult mixed breed dogs were used in this study (n = 6).

METHODS

 Nineteen retroreflective markers were applied to the skin of dogs' right forelimbs. Dogs were trotted and walked through the calibrated testing space. The first five good trials were used to generate sagittal plane (flexion and extension angle) waveforms from 3 different models (JCS, LIN and SEG) for the shoulder, elbow and carpal joints. The JCS model also generated transverse and frontal plane joint angular data (internal/external and abduction/adduction angles) for all three joints. Minimum, maximum and total angular displacement was calculated for each joint. Comparison of sagittal plane waveforms was performed before and after waveform alignment using statistical parametric mapping.

RESULTS

 Each model produced similar sagittal plane waveforms, though the LIN model had a greater vertical shift along the y-axis for the shoulder and elbow. Before waveform alignment, differences were revealed between the LIN model when compared to JCS or SEG model at a trot. No differences were revealed at a walk. After waveform alignment, no differences were revealed between models at a walk or trot. There were no differences in angular displacement measurements between models before or after waveform alignment at a walk or trot.

CONCLUSIONS

 The 3D JCS model reported in this study produced sagittal plane waveforms comparable to conventional 2D models while also providing joint specific information from other planes of motion.

Center of pressure and ground reaction forces in Labrador and Golden Retrievers with and without hip dysplasia at 4, 8, and 12 months of age

Canine hip dysplasia (CHD) is a common orthopedic disease. Owing to the importance of CHD in affected dogs, both clinically and for their use in breeding or work, increasing attention is being given to early diagnosis. Therefore, early clinical and radiological examination of young animals is increasingly in demand, whereas common CHD screening according to the Fédération Cynologique Internationale (FCI) is usually performed at the age of 12 months or even older in Europe. One way to objectively evaluate gait pattern is to measure the ground reaction forces (GRFs) and center of pressure (COP). In this study, we used a pressure plate to evaluate the GRF and COP parameters for 32 Labrador Retrievers and 17 Golden Retrievers at 4, 8, and 12 months of age. The dogs also underwent radiological examination of the hip joints following the FCI rules at the age of at least 12 months, which were grouped as sound (FCI grade A or B) and diseased (FCI grade C or worse). The results revealed significantly higher COP values in both breeds in the diseased limb groups at any measurement point during walking, with the most pronounced results obtained at 8 months of age. Furthermore, COP values during walking were significantly higher at 4 months than at 8 and 12 months in both the sound and diseased limb groups, indicating an increased stability of the gait pattern. Except for COP-Speed, the values of all COP parameters were higher during walking than during trotting at 4 months of age (i.e., COP-Speed was higher when trotting), indicating that the 4-beat gait in walk is more difficult to control for puppies than the 2-beat gait in trot. Overall, our results support the early evaluation of CHD in growing animals using non-invasive methods.

Compensatory Changes in Ground Reaction Forces in Small and Large Breed Dogs with Unilateral Hindlimb Lameness in Comparison to Healthy Dogs

OBJECTIVE

 The aim of this study was to investigate whether small- to medium-sized dogs with a naturally occurring unilateral hindlimb lameness show the same compensatory changes in ground reaction forces as large-breed dogs and how the changes are displayed compared with healthy small- to medium-sized dogs.

STUDY DESIGN

 Small- to medium-sized dogs (n = 15) and large-breed dogs (n = 16) with unilateral rupture of the cranial cruciate ligament were examined. The kinetic parameters peak vertical force and vertical impulse of the two groups were compared with each other and compared with healthy Beagles (n = 15) and with healthy Labrador Retrievers (n = 17), respectively.

RESULTS

 The healthy Beagle group showed a significantly higher weight loading on the forelimbs compared with the healthy Labrador group. The affected groups in comparison with the corresponding healthy groups showed a higher load on the non-affected body half and a significant lower weight bearing on the affected limb. Comparing the two affected groups, no significant difference could be found.

CONCLUSION

 Despite a substantially different initial situation regarding weight distribution of the examined small- to medium-sized dogs and large dogs, a unilateral hindlimb lameness leads to the same compensatory changes (cranial and lateral shift of the body mass centre).

Effect of a Corset on the Gait of Healthy Beagle Dogs

Simple Summary

In recent years, corsets have been used in the prevention of nerve diseases in dogs and in their rehabilitation following surgery. The Anifull Dog’s Corset Pro, made by Daiya Industry Co., Ltd., is manufactured and sold for this purpose, but no studies have yet been conducted to verify its effectiveness. To evaluate the effects of the corset, we analyzed the gait of healthy beagle dogs that were or were not wearing the Anifull Dog’s Corset Pro. We found no difference in the walking speed of the dogs, but wearing the corset reduced the horizontal sway of the back. In conclusion, this corset does not affect the gait of dogs and may help body stability. Therefore, the Anifull Dog’s Corset Pro may be useful for the treatment of dog nerve conditions.

Abstract

The prognosis for intervertebral disc disease (IVDD), a common neurologic disease in dogs, varies, with some cases requiring long-term rehabilitation. Corsets are used as part of the physical rehabilitation of dogs, and one of these, the Anifull Dog’s Corset Pro, is manufactured and sold by Daiya Industry Co., Ltd. This corset is used to relieve pain caused by spinal cord and vertebral diseases, and to prevent neurological conditions from worsening, by limiting spinal movement. However, the effect of the Anifull Dog’s Corset Pro on gait has not yet been clarified. Therefore, we aimed to evaluate the effects of this corset on the gait of dogs using kinematic and kinetic analyses. Five healthy beagle dogs wearing corsets were trotted, kinematic and kinetic parameters were measured using motion capture and force plates, and the results were compared to those obtained when the dogs were not wearing a corset. The range of motion of the angle formed by the 13th thoracic vertebra and the 7th lumbar vertebra at the apex of the 7th cervical vertebra was significantly reduced in the corset-wearing dogs. Thus, the Anifull Dog’s Corset Pro may improve trunk stability without affecting gait.

Functional assessment of the gluteus medius, cranial part of the biceps femoris, and vastus lateralis in Beagle dogs based on a novel gait phase classification

In humans, walking analysis based on the gait phase classification has been used for interpretation of functional roles of different movements occurring at individual joints, and it is useful for establishing a rehabilitation plan. However, there have been few reports on canine gait phase classification, and this is one of the reasons for preventing progress in canine rehabilitation. In this study, we determined phases of the canine gait cycle (GC) on the basis of the phase classification for human gait. The canine GC was able to be divided into initial contact (IC) and the following 5 phases: loading response (LR), middle stance (MidSt), pre-swing (PSw), early swing (ESw), and late swing (LSw). Next, the hind limb joint angles of the hip, stifle and tarsal joints and results of surface electromyography of the gluteus medius (GM), cranial part of the biceps femoris (CBF) and vastus lateralis (VL) muscles in relation to the gait phases were analyzed. The activities of three muscles showed similar changes during walking. The muscle activities were high in the LR phase and then declined and reached a minimum in the PSw phase, but they increased and reached a peak in the LSw phase, which was followed by the LR phase. In conclusion, the multiphasic canine GC was developed by modification of the human model, and the GC phase-related changes in the muscle activity and joint angles suggested the functions of GM, CBF and VL muscles in walking.

Different conformations of the German shepherd dog breed affect its posture and movement

The conformation of the German shepherd dog (GSD) varies considerably within the breed. These differences may result in large variation in the movement and limb loading and undesirable consequences to their musculoskeletal health. This study aimed to investigate the relationship between conformation and biomechanical measures in 60 GSDs. Full body kinematic and kinetic measures were computed from 3D motion capture and pressure data. The dogs were divided into groups based on their back slope and curvature. Correlation analysis and statistical differences between groups showed that GSDs with a greater back slope have a greater contact area in their forelimbs and place them closer together when standing (n = 60). During trot, the dogs with sloped back showed a greater vertical force in the forelimbs and a greater mid-thoracic flexion (n = 60). Unilateral differences were found in the stifle flexion, hock flexion and hock adduction, suggesting greater movement asymmetry with an increase in the back slope (n = 30). In conclusion, several biomechanical parameters are affected by the GSD's slope of the back and not by its curvature. Further studies are required to determine whether the variation in movement, posture and conformation within the breed relates to an increased susceptibility to musculoskeletal disorders.

Study of bilateral elbow joint osteoarthritis treatment using conditioned medium from allogeneic adipose tissue-derived MSCs in Labrador retrievers

Canine elbow dysplasia is a common cause of forelimb lameness in dogs and can lead to development of osteoarthritis (OA). A potential alternative to pain management is the use of a safe cell-free based therapy through trophic and paracrine factors of mesenchymal stem cells (MSCs). The aim of study was to identify the profile of selected mediators of potential clinical relevance in synovial fluid (SF) samples of dogs with elbow OA and analyse the range of motion (ROM) before and after cell-free MSCs-based treatment. In this study, conditioned medium from allogeneic canine adipose tissue - derived MSC (CM-AD-MSC) was prepared and administered into both elbow joints with OA in six Labrador retriever dogs (n = 6) on day 0 and 14 without creating a control group with a placebo. The SF of the elbow joints was analysed for the presence of several biomolecules (IL-6, IL-10, IL-8, IL-2, IL-12, TNF-αIFN-γ, MMP-3TIMP-1) before and after intraarticular applications of CM-AD-MSC. Kinematic analysis was used to assess the clinical effect of CM-AD-MSC. Analyses of SF and ROM were performed on days 0, 14 and 42. Concentration levels of MMP-3, TIMP-1, IL-6 and TNF-α in SF showed significant differences before and after the treatment (P < .05). There was a significant improvement in ROM between day 0 and 42 (P < .001). No severe adverse events were observed during the study. Results support the potential supportive effect of CM-AD-MSC as a noninvasive therapeutic tool for pain management of OA elbow joints in dogs.

Review of kinematic analysis in dogs

Objective gait analysis techniques aid investigators in the study of motion. Kinematic gait analysis techniques that objectively quantitate motion are valuable tools used to understand normal and abnormal motion in domestic animals. Recent advances in video technology have made the study of motion more readily accessible. Available systems can document gait in two or three dimensions (2D or 3D, respectively). Knowledge of fundamental gait analysis concepts is critical to generating meaningful data. The objective of this report is to review principles of kinematic data collection and analyses, with a focus on differences between 2D and 3D systems.

Comparison of the Vertical Force Distribution in the Paws of Dogs with Coxarthrosis and Sound Dogs Walking over a Pressure Plate

Simple Summary

The study of biomechanics for dogs with coxarthrosis is an important tool for diagnosis and treatment evaluation. Seeking a better view of the load distribution during the gait in dogs with coxarthrosis, we used a pressure plate to measure the vertical forces in the paws. The results suggested that walking dogs with coxarthrosis redistributed the load mainly to the caudal quadrants of the paws of the unaffected limbs. The performed methodology is another new possibility for the evaluation and clarification of biomechanical events in the course of coxarthrosis.

Abstract

In the present study, we used a pressure plate to investigate the ground reaction forces of limbs and the vertical force distribution (VFD) within the paws of dogs with coxarthrosis. We included 23 sound dogs (G_Sou) and 23 dogs with hip osteoarthrosis (G_Cox). The dogs walked over a pressure plate and the peak vertical force (PFz), vertical impulse (IFz) as the percentage of the total force, and time of occurrence of PFz as a percent of the stance phase duration (TPFz%) were evaluated, as well for the entire limb as in the paws (where the paws were divided into four quadrants). The G_Cox presented a lower PFz% in the lame hind limb than in others and transferred the weight to the caudal quadrants of the front limbs. IFz% was lower in the lame limb and was counterbalanced through higher loading of the caudal quadrants in all unaffected limbs. TPFz% was reached later in the lame limb than in the contralateral limb and the G_Sou, specifically in the caudomedial quadrant. In conclusion, we found complex compensatory effects of lameness in the hind limb, and this methodology was useful to define the VFD within the paws of dogs.

Canine hip dysplasia screening: Comparison of early evaluation to final grading in 231 dogs with Fédération Cynologique Internationale A and B

OBJECTIVES

This study aimed to verify if a significant difference exists between parameters in the early evaluation of normal and near-normal hip joints, to evaluate the influence of age and breed on the parameters, and to clarify the usefulness of a total score for differentiating between Fédération Cynologique Internationale (FCI) grade A and B hips.

METHODS

A total of 231 dogs were classified according to whether they had FCI A or B hips at adulthood, with measurements obtained at 14-28 weeks of age. The total score was calculated by the summation of the following quantitative parameters: angle of subluxation (AS), angle of reduction (AR), laxity index (LI), and dorsal acetabular rim slope (DARS). Logistic regression analysis was performed to establish the probability of the study population to develop an FCI B hip based on the total score. This was repeated for the highest score in combination with the worst-rated hip and once more for breeds.

RESULTS

No correlation between age and the parameters was found in the cohort, or for FCI A and B. The values of all the parameters were significantly lower in the FCI A group than in the FCI B group (AR: 4.42° ± 6.0° vs 7.62° ± 7.2°; AS: 0.45° ± 1.9° vs 1.55° ± 3.8°; LI: 0.32 ± 0.1 vs 0.36 ± 0.1; DARS: 3.30° ± 1.8° vs 3.77° ± 1.9°; TS: 11.47 ± 8.3 vs 16.65 ± 10.9). Labrador Retrievers and Golden Retrievers showed significant differences between parameters for both FCI grades. The range, where FCI A and B hips can be predicted on the basis of the total score, was different when assessed for the entire cohort, Labrador Retrievers, and Golden Retrievers.

CLINICAL SIGNIFICANCE

Our results show that even in normal and near-normal hips, the parameters significantly differed in the early evaluation. Moreover, cutoff values should be set for different breeds in the prediction of the FCI grade during early evaluation for a better breeding selection regarding canine hip dysplasia, one of the most common orthopedic diseases among large and giant breed dogs.

Effect of antioxidants, mitochondrial cofactors and omega-3 fatty acids on telomere length and kinematic joint mobility in young and old shepherd dogs - A randomized, blinded and placebo-controlled study

In dogs, decreasing telomere length is a biomarker for cellular aging. On a systemic level, aging affects the locomotor system in particular, leading to restricted joint mobility. As aging is thought to be related to oxidative stress, it may be counteracted by a diet enriched with antioxidants, mitochondrial cofactors and omega-3 fatty acids. This randomized, blinded and placebo-controlled study examined the influence of an accordingly enriched diet compared to a control diet on 36 young and 38 old shepherd dogs. At the outset, after 3 and after 6 months, mean and minimum telomere lengths were measured. Furthermore, minimum and maximum joint angles and range of motion of the shoulder, elbow, carpal, hip, stifle and tarsal joints were measured by computer-assisted gait analysis. A positive influence of the enriched diet on old dogs could be verified for minimum telomere length and all three parameters of the shoulder joint on the side with the higher vertical ground reaction force after 6 months. In the other joints there were less significant differences; in some cases they indicated a contrary influence of the enriched diet on young dogs, probably due to its reduced protein content. The greater effect of the enriched diet on minimum than on mean telomere length may be due to the higher preference of telomerase for short telomeres. The greater effect on shoulder joint mobility is explained by the greater influence of musculature and connective tissue in this joint. For elderly dogs it is advisable to feed these nutritional supplements.

Head and pelvic vertical displacement in dogs with induced swinging limb lameness: an experimental study

Background

Swinging limb lameness is defined as a motion disturbance ascribed to a limb in swing phase. Little is known about its biomechanics in dogs, particularly about the body motions that accompany it, such as vertical head and pelvic motion asymmetry. The aim of this study was to describe the changes in vertical head and pelvic motion asymmetry in dogs with induced swinging limb motion disturbance, mimicking a swinging limb lameness. Fore- and hind-limb lameness was induced in ten sound dogs by placing a weight (200 g) proximal to the carpus or tarsus, respectively. Marker-based motion capture by eight infrared light emitting video cameras recorded the dogs when trotting on a treadmill. Body symmetry parameters were calculated, including differences between the two highest positions of the head (HDmax) and pelvis (PDmax) and between the two lowest positions of the head (HDmin) and pelvis (PDmin), with a value of zero indicating perfect symmetry.

Results

Induction of swinging forelimb lameness showed significant changes in HDmax (median and range: sound 1.3 mm [− 4.7 to 3.1], in the left side − 28.5 mm [− 61.2 to − 17.9] and in the right side 20.1 mm [− 4.4 to 47.5]) and, induction of swinging hind limb lameness showed significant changes in PDmax (sound 2.7 mm [− 7.4 to 7.2], in the left side − 10.9 mm [− 22.4 to 0.5] and in the right side 8.6 mm [− 3 to 30]), as well as an increased hip movement asymmetry (sound 1.6 mm [− 8.6 to 19.9], in the left side − 18.1 mm [− 36.7 to 5.4] and in the right side 15 mm [− 20.7 to 32.1]) (P < 0.05).

Conclusions

Induced swinging fore- and hind limb lameness resulted in significant increased asymmetry of the maximal vertical displacement movement of the head and pelvis, due to decreased lifting of the head in forelimb lameness and of the pelvis in hind limb lameness. The results suggest that asymmetry of the maximal vertical displacement of the head and pelvis (i.e. lifting) is a key lameness sign to evaluate during examination of swinging limb lameness.

Comparative kinematic gait analysis in young and old Beagle dogs

Age-related involution in dogs involves loss of muscle mass and changes in connective tissue and articular cartilage. The aim of this study was to examine whether an age-related influence on joint mobility can be detected in the absence of disease. Five young (mean age 2.0 years) and five old (mean age 10.4 years) healthy and sound Beagle dogs underwent computer-assisted gait analysis during locomotion on a treadmill. Shoulder, elbow, carpal, hip, stifle, and tarsal joint angles including joint angle progression curves, minimum and maximum joint angles, and range of motion (ROM) in degrees were analyzed. The old group had a smaller maximum joint angle (p = 0.037) and ROM (p = 0.037) of the carpal joint; there were similar tendencies in the shoulder, elbow, and carpal joints. Descriptive analysis of the progression curves revealed less flexion and extension of the forelimb joints. The results indicate restricted joint mobility of the forelimb in old dogs, primarily of the carpal joint. Results in the joints of the hindlimb were inconsistent, and the contrasting alterations may be due to a compensatory mechanism. As most alterations were found in the distal joints, these should receive particular attention when examining elderly dogs.

Kinematic adaptions to induced short-term pelvic limb lameness in trotting dogs

Background

Lameness due to paw injuries is common in the clinical practice. Although many studies investigated gait adaptations to diseases or injuries, mainly of the hip and knee, our understanding of the biomechanical coping mechanisms that lame dogs utilize is limited. Therefore, this study evaluated the kinematic changes associated with an induced, load-bearing pelvic limb lameness in healthy dogs trotting on a treadmill. Kinematic analysis included spatio-temporal comparisons of limb, joint and segment angles of all limbs. Key parameters compared between sound and lame conditions were: angles at touch-down and lift-off, minimum and maximum joint angles and range of motion.

Results

Significant differences were identified in each limb during both stance and swing phases. The most pronounced differences concerned the affected pelvic limb, followed by the contralateral pelvic limb, the contralateral thoracic limb and, to the least degree, the ipsilateral thoracic limb. The affected limb was retracted more, while the contralateral limb was protracted more, consistent with this limb bearing more body weight in lame dogs.

Conclusions

Kinematic adaptations involved almost all segment and joint angles in the pelvic limbs, while they exclusively concerned distal parts of the thoracic limbs. Comparisons with tripedal locomotion reveal several striking similarities, implying that dogs use similar principles to cope with a partial or a total loss in limb function. Because kinematic alterations occurred in all limbs and not just the affected one, all limbs should be included in routine follow-ups and be part of the diagnostic and therapeutic care of canine patients.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1484-2) contains supplementary material, which is available to authorized users.

Kinetic gait analysis in English Bulldogs

Background

Canine breed conformation may interfere with locomotion and may predispose to orthopedic disease. Bulldogs have a high incidence of orthopedic diseases such as hip dysplasia. Kinetic gait analysis provides an objective way to assess and analyze locomotion. The aim of this study was to study the vertical forces of English Bulldogs during walk using a pressure sensitive walkway. We hypothesize that Bulldogs affected by orthopedic diseases have decreased weight bearing and asymmetric locomotion in the limbs despite having mild to no sings during clinical examination. Thirty English Bulldogs were tested. Peak vertical force, vertical impulse, rate of loading, stance phase duration, symmetry index, goniometry and incidence of orthopedic diseases were recorded.

Results

Although none of the dogs showed signs of pain or discomfort upon manipulation of the hip joints, all dogs had radiographic evidences of hip dysplasia and lack of significant peak vertical force, vertical impulse and stance time differences. The dogs had a mean hind limb symmetry index of 19.8 ± 19.5% and rates of loading ranged from 1.0 to 3.1.

Conclusions

Despite the lack of evident decrease in weight bearing, subclinical lameness can be inferred. The examined dogs had a mean hind limb symmetry index of 19.8 ± 19.5%. Symmetry indices reported in dogs free from orthopedic diseases range from 0.3 to 9.6%. Given non-lame dogs are expected to have a symmetry index close to 0%, data from this study suggests that Bulldogs have gait dysfunctions, which translates into hind limb asymmetries and rate of loading was consistent with severe hip dysplasia despite no visible signs of gait dysfunction. Future studies comparing lame and non-lame Bulldogs are warranted.

Etiopathogenesis of Canine Hip Dysplasia, Prevalence, and Genetics

First identified in 1935, canine hip dysplasia is thought to be the most common orthopedic condition diagnosed in the dog. It is most prevalent in large and giant breed dogs, with a complex polygenic mode of inheritance, and relatively low heritability. External factors including caloric intake when growing have a significant effect on phenotypic expression. Initial joint laxity progresses to osteoarthritis due to subluxation and abnormal wearing. Selective breeding programs to attempt to decrease prevalence have shown modest results so far.

The magnitude of muscular activation of four canine forelimb muscles in dogs performing two agility-specific tasks

Background

The purpose of this study was to measure the muscular activation in four forelimb muscles while dogs performed agility tasks (i.e., jumping and A-frame) and to provide insight into potential relationships between level of muscular activation and risk of injury. Muscle activation in eight healthy, client-owned agility dogs was measured using ultrasound-guided fine-wire electromyography of four specific forelimb muscles: Biceps Brachii, Supraspinatus, Infraspinatus, and Triceps Brachii – Long Head, while dogs performed a two jump sequence and while dogs ascended and descended an A-frame obstacle at two different competition heights.

Results

The peak muscle activations during these agility tasks were between 1.7 and 10.6 fold greater than walking. Jumping required higher levels of muscle activation compared to ascending and descending an A-frame, for all muscles of interest. There was no significant difference in muscle activation between the two A-frame heights.

Conclusions

Compared to walking, all of the muscles were activated at high levels during the agility tasks and our findings indicate that jumping is an especially demanding activity for dogs in agility. This information is broadly relevant to understanding the pathophysiology of forelimb injuries related to canine athletic activity.

Kinematic and spatiotemporal assessment of habituation to treadmill walking in Labrador retrievers

Background

This study investigated differences in kinematic and spatiotemporal variables in Labrador retrievers during introduction to treadmill walking, with the aim to determine the time required for them to become habituated. Twenty-five healthy, treadmill-naive Labrador retrievers participated in the study. The total angular displacement of the carpus, elbow, tarsus and stifle, as well as stride time and stance duration were calculated from the 3-D tracking of skin mounted reflective markers recorded with 6 infrared light emitting video cameras at 240 Hz. The measurements were done at two walking speeds, 0.78 and 0.96 m/s, in six sessions on the treadmill during two consecutive days.

Results

With a 1–2 min acclimatization period following each treadmill speed change, mean values of the study variables were significantly different from the last training session mainly in the first session on the first day. However, between-stride variability was significantly larger for at least one variable even in the fourth session for the slower walking speed, and in the fifth session for the higher walking speed.

Conclusions

The results show the importance of proper pre-training of dogs in locomotion studies at walk using a treadmill, and the need to consider not only variable mean values but also between-stride variability, in order to ensure that dogs are sufficiently accustomed to allow collection of reliable data.

Evaluation of inertial measurement units as a novel method for kinematic gait evaluation in dogs

OBJECTIVE

To evaluate the use of inertial measurement units (IMU) for quantification of canine limb kinematics.

METHODS

Sixteen clinically healthy, medium-sized dogs were enrolled. Baseline kinematic data were acquired using an optical motion capture system. Following this baseline data acquisition, a harness system was used for attachment of IMU to the animals. Optical kinematic data of dogs with and without the harness were compared to evaluate the influence of the harness on gait parameters. Sagittal plane joint kinematics acquired simultaneously with IMU and the optical system were compared for the carpal, tarsal, stifle and hip joints. Comparisons of data were made using the concordance correlation coefficient (CCC) test and evaluation of root mean squared errors (RMSE).

RESULTS

No significant differences were demonstrated in stance duration, swing duration or stride length between dogs instrumented with or without the harness, however, mean RMSE values ranged from 4.90° to 14.10° across the various joints. When comparing simultaneously acquired optical and IMU kinematic data, strong correlations were found for all four joints evaluated (CCC: carpus = 0.98, hock = 0.95, stifle = 0.98, hip = 0.96) and median RMSE values were similar across the joints ranging from 2.51° to 3.52°.

CONCLUSIONS AND CLINICAL RELEVANCE

Canine sagittal plane motion data acquisition with IMU is feasible, and optically acquired and IMU acquired sagittal plane kinematics had good correlation. This technology allows data acquisition outside the gait laboratory and may provide an alternative to optical kinematic gait analysis for the carpal, tarsal, stifle, and hip joints in the dog. Further investigation into this technology is indicated.

A validated approach for collecting fine-wire electromyographic recordings in four canine shoulder muscles during highly dynamic tasks

This study investigated the feasibility of obtaining ultrasound-guided intramuscular fine-wire electromyographic (fEMG) recordings from four canine shoulder muscles during highly dynamic activities. Four cadaveric canines were utilised to confirm the appropriate anatomical landmarks and the use of real time ultrasound guidance for electrode placement for four shoulder muscles: Biceps Brachii (BB), Supraspinatus (SP), Infraspinatus (IF), and Triceps Brachii – Long Head (TBLH). Electromyographic activity of the left BB, S P, IF, and TBLH was then recorded in two research dogs while walking and trotting to refine the data collection procedures. Finally, the full experimental protocol was piloted with two client-owned, specially-trained agility dogs, confirming the feasibility of collecting fEMG recordings while performing dynamic, highly-specific agility-related tasks and verifying our EMG amplitude normalisation protocol to enable comparisons across muscles and performance tasks. We present specific guidelines regarding the placement of fEMG electrodes and data collection/normalisation procedures to enable investigations of muscle activation during dynamic activities.

Kinematic analysis of forelimb and hind limb joints in clinically healthy sheep

BACKGROUND

Variations associated with sex, age, velocity, breed and body geometry should be considered in the determination of kinematic parameters for a gait considered normal. Therefore, this study aimed to evaluate kinematic patterns of forelimbs and hind limbs in clinically normal sheep from two different age groups walking at a constant velocity. The hypothesis was that the age may influence sagittal plane kinematic patterns. Fourteen clinically healthy female sheep were divided into Group 1--seven animals aged from 8 to 12 months, and Group 2--seven animals aged above 5 years. Before starting data collection, the sheep were trained to be conducted for walking in a pre-determined space at constant velocity. A minimum of 5 valid trials were obtained from the right and left sides of each sheep. Data were analyzed by use of a motion-analysis program. Flexion and extension joint angles (maximum, minimum, displacement), and angular velocity (maximum, minimum) were determined for the shoulder, elbow, carpal, hip, stifle, and tarsal joints.

RESULTS

Within each group, no significant differences were observed between the right and left limbs in all kinematic variables. Significant differences were observed in the following kinematic parameters between G1 and G2: minimum angle (G1 < G2), angular displacement (G1 > G2), maximum angular velocity (G1 > G2), minimum angular velocity (G1 > G2) of the carpus; angular displacement (G1 > G2), minimum angular velocity (G1 > G2) of the shoulder; minimum angle (G1 > G2), angular displacement (G1 < G2) of the tarsus; maximum angular velocity (G1 < G2) of the stifle; maximum angular velocity G1 > G2 of the hip. The lengths of both forelimbs and hind limbs differed between groups (G1 < G2). The Froude number differed between groups for forelimbs and hind limbs.

CONCLUSIONS

In conclusion, sheep of two different ages walking at a constant velocity present, within the same group, similar kinematic data between sides, and exhibit some differences in kinematic variables that may be age-related or body size. Further studies using sheep walking at similar Froude numbers are necessary to exclude the body size.

The Effect of Examiner Variability on Multiple Canine Stifle Kinematic Gait Collections in a 3-Dimensional Model

OBJECTIVE

To evaluate examiner variability in a superficial skin marker model of canine stifle kinematics.

STUDY DESIGN

Experimental.

ANIMALS

Six clinically normal dogs.

METHODS

Dogs had 11 retroreflective markers fixed to the skin on the right hindlimb. Dogs were trotted 5 times through the calibrated testing space and this was repeated on 4 different testing days. Examiner A applied all markers to a dog and collected 6 good trials for analysis. The markers were then removed and Examiner B immediately repeated the process on the same dog. This was repeated for each dog on the 4 testing days. The dogs were trotted at a velocity of 1.70-2.10 m/s through the testing space to obtain the dynamic data sets. Comparisons were performed with Fourier analysis and Generalized Indicator Function Analysis (GIFA). Significance was set at P < .05 for all comparisons.

RESULTS

Fourier analysis and GIFA found differences within and between examiners. Fourier analysis found no differences in sagittal and transverse planes for the experienced (A) and novice examiner (B), respectively. Fourier analysis detected fewer differences for the experienced examiner (A).

CONCLUSION

Variability occurs within and between examiners using the same kinematic model. Transverse and frontal plane kinematics produce variable results between examiners. Prior experience with the model reduces the amount of variability and results in consistent and repeatable sagittal plane kinematic data collection.

EFFECTS OF PELVIC AND FEMORAL POSITIONING ON CANINE NORBERG ANGLE MEASUREMENTS AND TEST–RETEST RELIABILITY: A COMPUTED TOMOGRAPHY-BASED SIMULATION STUDY

Canine hip dysplasia is a common disease in dogs, often diagnosed by using the Norberg angle (NA), an index for the laxity of the hip joint. Measurement of the NA can be affected by the pelvic and femoral positioning during imaging, the effects and test–retest reliability of which have not been documented. To bridge the gap in knowledge, computed tomography data from 11 Labrador Retriever dogs were obtained and used to generate synthetic ventrodorsal radiographs of the hip for NA measurements via a perspective projection model. Twenty-five synthetic radiographs of the hips were generated at positions defined by combinations of five pelvic tilt angles (-20° to 20° at 10° intervals) and five femoral elevation angles (from full extension to 40° at 10° intervals). For each radiograph, the NA was measured three times by each of the two experienced veterinarian examiners. It was found that both the increase in caudal pelvic tilt and femoral elevation increased the measured NA, although the intra- and inter-examiner reliability was very good for a given hip position. The current results suggest that careful positioning of the pelvis and femur during radiographic imaging is critical for accurately measuring the NA, and thus the laxity of the hip, for the clinical diagnosis of hip dysplasia.

Longitudinal gait development and variability of growing pigs reared on three different floor types

Biomechanical investigation into locomotor pathology in commercial pigs is lacking despite this being a major concern for the industry. Different floor types are used in modern, intensive pig production systems at different stages of the pigs' production cycle. The general perception holds that slatted and/or hard solid concrete surfaces are inferior to soft straw-covered floors regarding healthy musculoskeletal development. Previous studies have compared pigs housed on different floor types using clinical, subjective assessment of leg weakness and lameness. However, reliability studies generally report a low repeatability of clinical lameness scoring. The objective of this study was to quantitatively assess the long-term effect of pen floors, reflected in the biomechanical gait characteristics and associated welfare of the pigs. A cohort of 24 pigs housed on one of three different floor types was followed from 37 to 90 kg average liveweight, with gait analysis (motion capture) starting at 63 kg. The three floor types were fully slatted concrete, partly slatted concrete and deep straw-bedded surfaces, all located within the same building. Pigs underwent five repeated camera-based motion captures, 7 to 10 days apart, during which 3D coordinate data of reflective skin markers attached to leg anatomical landmarks were collected. Pigs walked on the same solid concrete walkway during captures. One-way ANOVA and repeated measures ANOVA were used to analyse the gait data. Results revealed changes over time in the spatiotemporal gait pattern which were similar in magnitude and direction for the pigs from different floor types. Significant increases in elbow joint flexion with age were observed in all pigs (P⩽0.050; +6°). There were few differences between floor groups, except for the step-to-stride ratio in the hind legs being more irregular in pigs housed on partly slatted floors (P=0.012; 3.6 times higher s.d.) compared with those on 5 to 10 cm straw-bedding in all pen areas. As the level of clinical problems was generally low in this cohort, it may be that floors elicit problems only when there is a primary predisposing factor increasing weakness in susceptible tissues.

Kinematic and temporospatial assessment of habituation of Labrador retrievers to treadmill trotting

This study investigated differences in kinematic and temporospatial variables in treadmill-naïve dogs when introduced to treadmill trotting and the time required to for them to become habituated to the treadmill. Twenty-four healthy Labrador retrievers, with an age range of 22-36 months and with no history of orthopaedic disease, were included in the study. A motion capture system registered kinematic variables of the carpus, elbow, tarsus and stifle, along with stride time and stance duration, at 240 Hz. Six sessions, each lasting 8-10 min, walking and trotting on the treadmill were performed with each dog, with three sessions on each of two consecutive days. The between-stride variability of total angular displacement of the carpus, elbow, stifle and tarsus, as well as the stride and stance time, was higher during the day 1 trotting sessions than in the last session of day 2. These stabilised to non-significant levels before the second session on the second day of measurements and thus habituation was achieved.

Soft tissue artifact in canine kinematic gait analysis

OBJECTIVE

To investigate, noninvasively, the soft tissue artifact (STA) in canine kinematic gait analysis.

STUDY DESIGN

Experimental study.

ANIMALS

Labrador retrievers (n = 4).

METHODS

Kinematic study: Reflective markers were glued to the skin over bony landmarks, with the distance between 2 markers representing the length of the underlying scapula, humerus, ulna, femur, and crus. The distance between these markers (marker distance [MD]) was measured with infrared cameras while the dogs stood still or walked on a treadmill. Fluoroscopy study: Radiopaque markers were glued on the skin over the spinous process of the L6 vertebra and the stifle to allow fluoroscopic observation of the markers and underlying skeletal segments while the dogs walked on the treadmill. The position of the markers was compared with the position of the underlying skeletal segments during different phases of the step cycle.

RESULTS

Kinematic study: Significant differences were found between MD during standing and walking for all bones investigated. Mean percentage differences in MD ranged from -18% to +6%. Fluoroscopy study: Significant displacements relative to the bony landmarks were found ranging from 0.4 to 1.2 cm.

CONCLUSIONS

Analysis of the motion of skeletal structures with the use of markers attached to the skin showed that the skin moves relative to underlying skeletal structures. When working with a 3-D motion-capture system using skin markers, researchers should be aware that the STA could significantly influence their results.

The challenges of assessing osteoarthritis and postoperative pain in dogs

The challenge of measuring pain in veterinary medicine is compounded by the lack of fully validated, reliable methods to measure and assess pain in nonverbal patients. In human medicine, there are numerous, validated pain assessment tools (PATs) for assessing various, specific types of pain. The advances in human medicine pain management and numerous validated pain scales should serve as incentives and templates to facilitate similar advances in the development of validated PATs for use in dogs (and other species). The limited number of canine PATs constrains our ability to adequately and reliably assess pain. Improving the ability to quantify osteoarthritis and postoperative pain in dogs would enhance the development of analgesics for animals, advance the management of animal pain, facilitate the use of animal pain models in preclinical trials for human analgesics, and provide insight into the quantification of pain responses in humans who lack the ability to adequately communicate. This review describes the need for practical, valid, and reliable PATs for use in veterinary patients and discusses some currently available PATs commonly used to evaluate acute and chronic pain in dogs.

Hind limb kinematics during therapeutic exercises in dogs with osteoarthritis of the hip joints

OBJECTIVE

To assess joint kinematics in dogs with osteoarthritis of the hip joints during walking up an incline or down a decline and over low obstacles and to compare findings with data for nonlame dogs.

ANIMALS

10 dogs with osteoarthritis of the hip joints (mean ± SD age, 6.95 ± 3.17 years; mean body weight, 34.33 ± 13.58 kg) and 8 nonlame dogs (3.4 ± 2.0 years; 23.6 ± 4.6 kg).

PROCEDURES

Reflective markers located on the limbs and high-speed cameras were used to record joint kinematics during walking up an incline or down a decline and over low obstacles. Maximal flexion, extension, and range of motion of the hip joints were calculated.

RESULTS

Osteoarthritis of the hip joints reduced extension of both hip joints and flexion of the contralateral hind limb, compared with flexion of the lame hind limb, during walking down a decline. Walking up an incline resulted in decreased extension of the stifle joint in both hind limbs of osteoarthritic dogs; extension was significantly decreased for the lame hind limb. During walking over low obstacles, maximal flexion of the stifle joint was increased significantly for the contralateral hind limb. Maximal flexion was increased in both tarsal joints.

CONCLUSIONS AND CLINICAL RELEVANCE

Osteoarthritis of the hip joints led to complex changes in the gait of dogs, which involved more joints than the affected hip joint alone. Each exercise had specific effects on joint kinematics that must be considered when planning a rehabilitation program.

Kinematic analysis in healthy and hip-dysplastic German Shepherd dogs

This study investigated kinematic patterns in clinically normal German Shepherd dogs (GSDs) compared to those with hip dysplasia and with no clinical signs of lameness. Two groups of GSDs, including 10 clinically healthy dogs (G1) and 10 with hip dysplasia (G2), were trotted on a treadmill at a constant speed. Kinematic data were collected by a 3-camera system and analysed by a motion-analysis program. Flexion and extension joint angles and angular velocities were determined for the shoulder, elbow, carpal, hip, stifle, and tarsal joints. Within each group, the differences between the right and left limbs in all kinematic variables were not significant. Minimum angle, angular displacement and minimum angular velocity did not differ between groups. Significant differences were observed in the maximum angular velocity and maximum angle of the hip joint (dysplastic>healthy), and in the maximum angular velocity of the carpal joint (healthy>dysplastic). It was concluded that, when trotting on a treadmill, dysplastic dogs with no signs of lameness may present joint kinematic alterations in the hind as well as the forelimbs.

Pelvic limb kinematics and surface electromyography of the vastus lateralis, biceps femoris, and gluteus medius muscle in dogs with hip osteoarthritis

OBJECTIVE

To measure the activity patterns of the vastus lateralis (VL), biceps femoris, and gluteus medius (GM) muscle at a walk in sound dogs and dogs with hip osteoarthritis (OA).

ANIMALS

Dogs (n = 10) with hip OA and 7 clinically sound dogs.

METHODS

Self-reflective markers and a high-speed camera system were used for kinematic measurements and surface electrodes were used for the electromyography (EMG). All measurements were performed on walking dogs. Maximal, minimal, and mean values of the joint angles were evaluated, together with the surface EMG data.

RESULTS

In all muscles investigated, mean activity was significantly decreased during the early swing phase in dogs with hip OA. The VL and GM muscle of the clinically worse pelvic limb had significantly higher activity than the contralateral pelvic limb during early stance.

CONCLUSION

The muscles investigated were significantly affected by hip OA. This finding suggests that there is a more distinct resting phase of the muscles during swing and a higher activity during early stance.

Padronização e teste da plataforma de força em padrão ortostático em cães

O objetivo deste trabalho foi padronizar e testar o uso da plataforma de força em padrão ortostático em cães, na avaliação do apoio e distribuição do peso nos membros, permitindo visualizar uma possível transferência em pacientes ortopédicos com afecções articulares. Foram realizadas avaliações clínica - graus de claudicação e exame radiográfico - e biomecânica na plataforma de força, por coleta estática de 16 pacientes cirúrgicos ortopédicos com afecções coxofemoral da rotina hospitalar (grupo tratado), e de seis cães saudáveis, sem histórico de problemas ortopédicos (grupo-controle). Com base no grupo-controle, foi possível delinear uma metodologia adequada para cães em coleta estática e testá-la no grupo tratado. A plataforma em padrão ortostático mostrou ser um parâmetro objetivo, eficiente e mais sensível que os demais, sendo seu uso adequado na avaliação de pacientes ortopédicos.

Evaluation of a three-dimensional kinematic model for canine gait analysis

OBJECTIVE

To evaluate a 3-D kinematic model of the hind limb developed by use of a joint coordinate system in dogs.

ANIMALS

6 clinically normal adult mixed-breed dogs.

PROCEDURES

17 retroreflective markers were affixed to the skin on the right hind limb of each dog. Eight infrared cameras were arranged around a gait platform to record marker locations as dogs were recorded moving through the calibrated space 5 times during a walk and trot at velocities of 0.9 to 1.2 m/s and 1.7 to 2.1 m/s, respectively. Local and global coordinate systems were established, and a segmental rigid-body model of the canine hind limb was produced. Dynamic 3-D joint kinematic measurements were collected for the hip, stifle, and tarsal joints.

RESULTS

Sagittal (flexion-extension), transverse (internal-external rotation), and frontal (abduction-adduction) plane kinematic measurements were acquired during each trial for the hip, stifle, and tarsal joints.

CONCLUSIONS AND CLINICAL RELEVANCE

The joint coordinate system allowed acquisition of 3-D kinematic measurements of the hip, stifle, and tarsal joints of the canine hind limb. Methods were described to model 3-D joint motion of the canine hind limb.

Kinematic motion analysis of the joints of the forelimbs and hind limbs of dogs during walking exercise regimens

OBJECTIVE

To assess forelimbs and hind limb joint kinematics in dogs during walking on an inclined slope (uphill), on a declined slope (downhill), or over low obstacles (cavaletti) on a horizontal surface and compare findings with data acquired during unimpeded walking on a horizontal surface.

ANIMALS

8 nonlame dogs (mean +/- SD age, 3.4 +/- 2.0 years; weight, 23.6 +/- 4.6 kg).

PROCEDURES

By use of 10 high-speed cameras and 10 reflecting markers located on the left forelimbs and hind limbs, joint kinematics were recorded for each dog during uphill walking, downhill walking, and walking over low obstacles or unimpeded on a horizontal surface. Each exercise was recorded 6 times (10 s/cycle); joint angulations, angle velocities and accelerations, and range of motion for shoulder, elbow, carpal, hip, stifle, and tarsal joints were calculated for comparison.

RESULTS

Compared with unimpeded walking, obstacle exercise significantly increased flexion of the elbow, carpal, stifle, and tarsal joints and extension in the carpal and stifle joints. Only uphill walking caused increased hip joint flexion and decreased stifle joint flexion; downhill walking caused less flexion of the hip joint. During obstacle exercise, forward angle velocities in the elbow and stifle joints and retrograde velocity in the tarsal joint changed significantly, compared with unimpeded walking. Joint angle acceleration of the elbow joint changed significantly during all 3 evaluated exercises.

CONCLUSIONS AND CLINICAL RELEVANCE

These evidence-based data indicated that each evaluated exercise, except for downhill walking, has a specific therapeutic value in physical therapy for dogs.

Diagnosis, genetic control and preventive management of canine hip dysplasia: a review

Despite expensive screening and breeding programmes, hip dysplasia (HD) continues to be one of the most common orthopaedic diseases in dogs. The vast majority of dogs afflicted with HD show minimal to no clinical signs, but it can also be a highly debilitating condition for both working and pet dogs. Hip joint laxity is considered a major risk factor for the development of degenerative joint disease and a definitive diagnosis is made if characteristic signs are evident on a ventrodorsal view of the pelvis. Early prediction of the condition can be made using stress radiographic techniques to evaluate the passive hip laxity. The diagnosis of HD may be used for the purpose of selecting breeding stock or to decide on the best treatment approach. Breeding programmes based on individual dog phenotypes have been ineffective and a selection procedure based on breeding value (BV) estimation is recommended. Traditional conservative and surgical treatment approaches are reserved for dogs with overt clinical signs of the disease but such treatments can be expensive and aggressive, and are often ineffective in eliminating clinical signs or subluxation and in preventing the development of degenerative joint disease. The implementation of breeding programmes based on BVs and further research into early prediction/diagnosis of HD and effective preventive treatment approaches are essential.

Comparison of two-dimensional and three-dimensional systems for kinematic analysis of the sagittal motion of canine hind limbs during walking

OBJECTIVE

To test the hypotheses that kinematic data of the sagittal motion of canine hind limbs during walking obtained with a 2-dimensional (2-D) system correlate well with those obtained with a 3-dimensional (3-D) system and that the data obtained with the 2-D system are repeatable.

ANIMALS

6 adult dogs with no evidence of lameness.

PROCEDURES

Hind limb motions of 6 walking dogs were recorded via 2-D video and 3-D optoelectric systems simultaneously. Five valid trials were digitized, and 5 data sets (2-D 60 Hz, 3-D 180 Hz, 3-D sagittal 180 Hz, 3-D 60 Hz, and 3-D sagittal 60 Hz) of a complete gait cycle were created for each dog. In sagittal data sets, 3-D data were reduced to exclude coordinates for mediolateral orientation. Temporospatial parameters; angles of hip, stifle, and tarsal joints; and coefficients of variation of angular measurements of each dog were calculated for each data set. Accuracy of the 2-D analysis was determined by calculating mean absolute differences and estimating agreement between the 2-D and 3-D 180-Hz data sets.

RESULTS

Values of joint angles and angular excursions measured with the 2-D system were repeatable and agreed with respective values obtained with the 3-D system. Reduction of the sampling rate had a greater impact on values of kinematic variables obtained with the 3-D system than did elimination of data on mediolateral orientation.

CONCLUSIONS AND CLINICAL RELEVANCE

Kinematic analysis using a 2-D video system provided accurate and repeatable data of the sagittal angular motion of canine hind limbs during walking.

Hip dysplasia in Estrela mountain dogs: prevalence and genetic trends 1991-2005

Three hundred and thirteen Estrela mountain dogs were examined for hip dysplasia (HD) using the standard ventrodorsal hip extended view, and graded into five categories (A, B, C, D and E) using the Fédération Cynologique Internationale's (FCI) scoring system. The Ortolani method was performed to evaluate hip joint laxity. Pedigree information was obtained from the Portuguese Kennel Club and the genetic trend was evaluated by calculating the mean breeding values (BVs) for the last 15 years, using the threshold model. HD was found in 66% of the dogs. There was low-moderate correlation between the results of the Ortolani test and FCI hip scores (r(s)=0.386; P<0.001). Grades of hip dysplasia were equal in both males and females (P=0.14) and in the animals' right and left sides (P=0.51). The mean BVs for HD were stable in dogs born between 1991 and 2003, and showed an improvement in 2004 and 2005. The data confirm the high prevalence and severity of HD in predisposed breeds that do not have breeding programmes in place. It also confirms an initial favourable change in BVs that is a likely consequence of the voluntary radiographic hip-screening programme.

Recent developments in canine locomotor analysis: a review

Subjective evaluation of canine gait has been used for many years. However, our ability to perceive minute details during the gait cycle can be difficult and in some respects impossible even for the most talented gait specialist. The evolution of computer technology in computer assisted gait analysis over the past 20 years has improved the ability to quantitatively define temporospatial gait characteristics. These technological advances and new developments in methodological approaches have assisted researchers and clinicians in gaining a better understanding of canine locomotion. The use of kinematic and kinetic analysis has been validated as a useful tool in veterinary medicine. This paper is an overview of the kinematic and kinetic analytical techniques of the last decade.