Kinematics of the elbow and stifle joints in greyhounds during treadmill trotting An investigation of familiarisation

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.

Reliability of range-of-motion measurements of healthy dogs examined while walking on a treadmill

OBJECTIVE

To determine the reliability of range-of-motion (ROM) measurements and describe physiologic differences in ROM or habituation effects during gait analysis of healthy dogs walking on a treadmill.

ANIMALS

11 orthopedically normal dogs.

PROCEDURES

ROM of appendicular joints was determined for each dog while walking on a treadmill on 3 consecutive examination days and once again 6 weeks later. Significant differences in ROM between examination days were determined and quantified. As a measure of reproducibility, the coefficient of variation for repeated measurements was calculated, as were the minimum differences necessary to distinguish between physiologic variation and true change in ROM.

RESULTS

Mean ROM of the shoulder, elbow, and carpal joints varied among examination days between 29.9° and 33.1°, 49.4° and 52.8°, and 7.7° and 88.1°, respectively. Mean associated minimum differences were 12.0°, 14.1°, and 35.6°. Mean ROM of the hip, knee, and tarsal joints varied between 32.9° and 35.8°, 33.7° and 36.8°, and 31.7° and 33.5°, respectively. Mean associated minimum differences were 16.2°, 14.0°, and 9.2°. Only ROM of the elbow joint was reproducible to a small degree. Few systematic effects were detected.

CONCLUSIONS AND CLINICAL RELEVANCE

Measurement of ROM in healthy dogs walking on a treadmill was shown to be diagnostically unreliable owing to high variation among examination days. However, random physiologic fluctuations could be distinguished from systematic effects, demonstrating the importance of reliably applicable threshold values for follow-up treadmill examinations. The applicability of the minimum differences determined here to orthopedically diseased dogs remains to be determined.

Biomechanics of the Canine Elbow Joint

The canine elbow joint is a complex joint, whose musculoskeletal anatomy is well investigated. During the last 30 years kinematic analysis has gained importance in veterinary research and kinematics of the healthy and medial coronoid disease affected canine elbow joint are progressively investigated. Video-kinematographic analysis represents the most commonly used technique and multiple studies have investigated the range of motion, angular velocity, duration of swing and stance phase, stride length and other kinematic parameters, mostly in the sagittal plane only. However, this technique is more error-prone and data gained by video-kinematography represent the kinematics of the whole limb including the soft tissue envelope. A more precise evaluation of the in vivo bone and joint movement can only been achieved using fluoroscopic kinematography. Based on recent studies significant differences in the motion pattern between healthy joints and elbows with medial coronoid disease could be detected. Thereby not only adaptive changes, caused by pain and lameness, could be described, but primary changes in the micromotion of the joint forming bones could be found, which potentially represent new factors in the pathogenesis of medial coronoid disease. This chapter gives a review of current literature on elbow joint kinematics, with particular focus onto pathologic biomechanics in dysplastic canine elbows.

Relation of Computed Tomography-Based Static Axial Radioulnar Incongruence Measurements under General Anaesthesia and Dynamic, In Vivo RUI during the Walk in Canine Elbow Joints with and without Medial Coronoid Process Disease

OBJECTIVE

 This study aimed to evaluate the correlation of static axial radioulnar incongruence (sRUI) measured under general anaesthesia with the real in vivo dynamic RUI (dRUI) during walking.

STUDY DESIGN

 This was a prospective clinical study that included 6 sound elbows (5 dogs) and 7 medial coronoid process disease (MCPD) affected elbows (6 dogs).

MATERIALS AND METHODS

 Static axial radioulnar incongruence was measured using the sphere fitting technique on computed tomography-based three-dimensional (3D) models of radius and ulna. The in vivo pose of radius and ulna was derived from radiostereometric analysis during the walk and transferred onto previously calculated 3D models. Dynamic RUI was measured on those adjusted models using the sphere fitting technique, providing a measurement of RUI over time during walk.

RESULTS

 Mean sRUI was 0.2 mm (standard deviation [SD]: 0.30) in control and 1.4 mm (SD: 0.73) in elbow joints with MCPD; being significantly different (p = 0.0035; confidence interval [CI]: 0.4772-1.8824). Mean dRUI in controls (-0.4 mm; SD: 0.47) was significantly different (p = 0.0004; CI: 0.9918-2.5225) from dRUI in the affected elbows (1.4 mm; SD: 0.73). Comparison of sRUI and dRUI within each group showed difference in the control group (0.2 vs. -0.4 mm; p = 0.0138; CI: 0.1820-1.0014). In affected elbows, no difference between sRUI and dRUI was found (1.4 vs. 1.4 mm; p = 0.8963).

CONCLUSION

 In normal elbow joints, sRUI does not represent the in vivo condition during weight bearing. Dynamic and slightly negative RUI occurs during loading (0.2 mm positive to -0.4 mm negative RUI). In MCPD affected elbows with sRUI, no dynamic change of RUI occurs during the walk.

Evaluation of post-operative complications, outcome, and long-term owner satisfaction of elbow arthrodesis (EA) in 22 dogs

The objective of this study was to report post-operative complications and outcomes in canines undergoing elbow arthrodesis (EA) with fixation techniques including bone plate fixation with a non-locking dynamic compression plate (DCP), bone plate fixation with a locking plate (LCP), and external skeletal fixator (ESF). Medical records of twenty-two cases that underwent EA between January 2009-December 2019 from 8 referral hospitals including both private practice and academic institutions were reviewed. Post-operative complications were classified as either minor or major, surgical evaluations were performed 8 weeks post operatively, and a follow-up questionnaire was sent to owners. Of the total 22 cases that met inclusion criteria, a total of 19/22 cases had complications, 12 major and 7 minor. Complications reported in 8/9, 7/9, and 4/4, for the DCP, LCP, and ESF fixation groups, respectively. Mild to moderate mechanical lameness was identified at surgical evaluation in 16/22 cases. Complete radiographic bone healing was achieved after 9 weeks in 19/22 cases. Long term owner follow up was available in 14/22 cases. Owners reported a good to normal quality of life in 13/14 cases and poor in one case. The majority of owners (11/14) reported good to excellent satisfaction with the outcome irrespective of persistent lameness. This study demonstrates that successful EA can be achieved using a variety of fixation methods, but persistent lameness is expected and complication rate is high.

Alterations in articular cartilage T2 star relaxation time following mechanical disorders: in vivo canine supraspinatus tendon resection models

Background

The role of altered joint mechanics on cartilage degeneration in in vivo models has not been studied successfully due to a lack of pre-injury information. We aimed 1) to develop an accurate in vivo canine model to measure the changes in joint loading and T2 star (T2*) relaxation time before and after unilateral supraspinatus tendon resections, and 2) to find the relationship between regional variations in articular cartilage loading patterns and T2* relaxation time distributions.

Methods

Rigid markers were implanted in the scapula and humerus of tested dogs. The movement of the shoulder bones were measured by a motion tracking system during normal gaits. In vivo cartilage contact strain was measured by aligning 3D shoulder models with the motion tracking data. Articular cartilage T2* relaxation times were measured by quantitative MRI scans. Articular cartilage contact strain and T2* relaxation time were compared in the shoulders before and 3 months after the supraspinatus tendon resections.

Results

Excellent accuracy and reproducibility were found in our in vivo contact strain measurements with less than 1% errors. Changes in articular cartilage contact strain exhibited similar patterns with the changes in the T2* relaxation time after resection surgeries. Regional changes in the articular cartilage T2* relaxation time exhibited positive correlations with regional contact strain variations 3 months after the supraspinatus resection surgeries.

Conclusion

This is the first study to measure in vivo articular cartilage contact strains with high accuracy and reproducibility. Positive correlations between contact strain and T2* relaxation time suggest that the articular cartilage extracellular matrix may responds to mechanical changes in local areas.

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.

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.

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.

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.

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.

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.

Ex vivo contact mechanics and three-dimensional alignment of normal dog elbows after proximal ulnar rotational osteotomy

OBJECTIVE

To evaluate the effect of proximal ulnar rotational osteotomy (PURO) on the contact mechanics and 3-dimensional (3D) alignment of cadaveric normal dog elbows.

STUDY DESIGN

Ex vivo biomechanical study.

ANIMALS

Unpaired thoracic limbs from 12 dogs (mean ± SD weight, 26 ± 4 kg).

METHODS

PURO consisted of a transverse osteotomy with 30° external rotation of the proximal segment. With the limb under 200 N axial load, contact area (CA), mean contact pressure (CP) and peak contact pressure (PCP) were measured using digital pressure sensors in the medial and lateral compartments and 3D static elbow poses were obtained, before and after PURO. Each specimen was tested at 115°, 135°, and 155° elbow flexion, with the antebrachium in neutral rotation, in 28° supination, and in 16° pronation. Repeated measures ANOVAs with post-hoc Bonferroni (P ≤ .05) were performed.

RESULTS

PURO caused significant changes, mostly at 135° elbow flexion and neutral antebrachial rotation, characterized by decreased CP (10%) and PCP (10%) in the medial compartment, and increased CP (27%) and PCP (23%) in the lateral compartment. The apex of the medial coronoid process translated 3.4 mm caudally, 1.7 mm abaxially, and rotated 1.8° externally relative to the radial head. Humeroradial varus angulation reduced by 6.7°.

CONCLUSIONS

In limited poses, PURO displaces the medial coronoid process caudally and abaxially and shifts contact pressures towards the lateral elbow compartment by decreasing varus angulation.

Kinetic and kinematic analysis of the right hind limb during trotting on a treadmill in Labrador Retrievers presumed predisposed or not predisposed to cranial cruciate ligament disease

OBJECTIVE

To identify gait characteristics during trotting on a treadmill in nonlame Labrador Retrievers presumed predisposed or not predisposed to cranial cruciate ligament disease (CCLD).

ANIMALS

Clinically normal Labrador Retrievers presumed predisposed (n = 10) or not predisposed (7) to CCLD.

PROCEDURES

The right hind limb of each dog was classified by use of a predictive score equation that combined tibial plateau angle and femoral anteversion angle as presumed predisposed (high score [> -1.5]) or not predisposed (low score [≤ -1.5]) to CCLD. Tarsal joint, stifle joint, and hip joint kinematics, net moments, and powers were computed.

RESULTS

The stifle joint was held at a greater degree of flexion in limbs presumed predisposed to CCLD (130.9° vs 139.3°). More power was generated by muscles acting on the stifle joint in the early stance phase of limbs presumed to be predisposed to CCLD (2.93 vs 1.64 W/kg). The tarsal joint did not reach the same degree of extension in limbs presumed predisposed to CCLD, compared with that in limbs presumed not predisposed to CCLD (179.0° vs 161.0°). Velocity, stance time, vertical and craniocaudal forces, angular velocities, and net joint muscle moments did not differ between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Gait mechanics of dogs with high (> -1.5) and low (≤ -1.5) tibial plateau angle and femoral anteversion angle scores were characterized on a treadmill, which may help in the identification of dogs predisposed to CCLD.

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.

Kinematic analysis of Labrador Retrievers and Rottweilers trotting on a treadmill

OBJECTIVES

The purpose of the study was to evaluate kinematic patterns in clinically normal Labrador and Rottweiler dogs trotting on a treadmill at a constant velocity.

METHODS

Ten Labrador Retrievers aged from 2.2 to 5.1 years, and 10 Rottweilers aged from two to 5.9 years were used. A three-dimensional capture system was used to perform analysis of joint kinematics. Kinematic data were collected by use of a triple-camera system. The kinematic study was performed first on the right side of the dog, and then on the left side. Data were analysed by use of a motion-analysis program. Flexion and extension joint angles, angular velocity and angular acceleration were determined for the shoulder, elbow, carpal, hip, stifle, and tarsal joints.

RESULTS

Within each group, the differences between the right and left limbs in all variables were not significant. Significant differences occurred between Labradors and Rottweilers in the following categories: angular displacement and minimum angular acceleration of the stifle (Rottweiler >Labrador); angular displacement and maximum angular velocity of the tarsus (Rottweiler >Labrador); minimum angular velocity of the shoulder (Labrador >Rottweiler); angular displacement, maximum angular acceleration, maximum angular velocity, and minimum angular velocity of the elbow (Labrador>Rottweiler); and maximum angle and maximum angular velocity of the carpus (Labrador>Rottweiler).

CLINICAL SIGNIFICANCE

Both breeds had similar kinematic patterns, but there were magnitude differences, especially of the elbow and stifle joints. Therefore, each breed should have a specific database.

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.

Kinematics of gait in golden retriever muscular dystrophy

The goal of this study was to quantify the two-dimensional kinematics of pathologic gait during over-ground walking at a self-selected speed at the stifle (knee) and hock (ankle) joints in six Golden Retriever Muscular Dystrophy (GRMD) dogs and six carrier littermates (controls). We found that GRMD dogs walked significantly slower than controls (p<0.01). At the stifle joint, both groups displayed similar ROM (range of motion), but compared to controls, GRMD dogs walked with the stifle joint relatively more extended. At the hock joint, GRMD dogs displayed less ROM (range of motion) and walked with the joint relatively less flexed compared to controls. We controlled for gait speed in all analyses, so the differences we observed in joint kinematics between groups cannot be attributed solely to the slower walking speed of the GRMD dogs. This is the first kinematic study of gait in the GRMD dog, an important step in using this model in pre-clinical trials.

Regional load bearing of the canine acetabulum

OBJECTIVE

To determine the load bearing areas of the canine acetabulum.

MATERIALS AND METHODS

A kinematic study of four healthy dogs was used to determine the orientation of the femur to the pelvis at mid-stance. Femora and pelves from 10 canine cadavers were loaded with the physiological canine hip reaction force and angle being replicated. Impression material placed within the acetabulum was extruded from areas of load bearing. Digital images before and after loading were used to assess if six different regions of the acetabulum were fully, partially or non-load bearing.

RESULTS

All areas of the acetabulum were partially or fully load bearing. The cranial and caudal thirds of the acetabulum were 7.9 and 13.1 times more likely to be fully load bearing than the central third, respectively. There was a significant difference in load bearing between the axial, middle and abaxial thirds of the acetabulum in all tests, with the middle and abaxial thirds 72.4 and 351 times more likely to be fully load bearing than the axial third, respectively.

CONCLUSION

The cranial and caudal thirds and the middle and abaxial thirds of the canine acetabulum are fully load bearing.

CLINICAL RELEVANCE

The caudal third of the canine acetabulum is loaded and therefore recommendations that fractures in this area be managed conservatively need to be reconsidered.

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

OBJECTIVE

To detect changes in joint kinematics of clinically sound dogs with or without radiographically detectable borderline hip dysplasia (HD).

ANIMALS

20 Belgian Shepherd Dogs (Malinois; mean +/- SD age, 2.75 +/- 1.32 years) with no clinical signs of HD.

PROCEDURES

Kinematic gait analysis was performed in Malinois walking on a treadmill. On the basis of results of radiographic examination for HD and in accordance with guidelines established by the Fédération Cynologique Internationale, dogs were assigned to group 1 (no radiographic signs of HD; 8 dogs) or group 2 (borderline HD; 12 dogs). Ground reaction forces and weight distribution among limbs and differences between groups were evaluated. Maximal sagittal angle during the stance and swing phases, the time at which they were detected, and angle velocities were calculated for joints of the hind limbs.

RESULTS

Ground reaction forces revealed no differences between groups. Dogs in group 1 had significant changes (earlier time for maximal flexion of the hip joint and less flexion and less range of motion of the stifle joint), compared with results for dogs in group 2. Maximal angle velocity of the stifle and tarsal joints was significantly lower during the swing phase in group 1 than in group 2.

CONCLUSIONS AND CLINICAL RELEVANCE

This study revealed that dogs with borderline HD had altered joint kinematics. Our data provide basic kinematic values for clinically sound and affected dogs and can be used to investigate the long-term effects for subclinical radiographic changes of the hip joints of dogs.

Kinematic analysis of the gait of 10 labrador retrievers during treadmill locomotion

The trotting gait of 10 sound, adult labrador retrievers was analysed using kinematic gait analysis on a purpose-built treadmill using video-based motion analysis software. The maximal angular displacement, minimal angular displacement, average angular displacement, and the maximal positive and negative angular velocities of the right elbow and right stifle were measured over five gait cycles at defined time points during each of five two-minute sessions. The dogs' trotting gait was not repeatable, either for individual dogs during the first session or between sessions, or between dogs at the same time points during a session.