A Quantitative Review of the Equinalysis System for Equine Locomotion Analysis

Movement analysis techniques allow objective and quantitative assessment of kinematic gait analysis. Consistent repeatability of the kinematic data is essential for such assessments. This study investigated whether the repeatability of a standardized Equinalysis Elite gait analysis system is sufficient to allow its use in clinical evaluation of equine lameness with reliable documentation of individual locomotion patterns. The extent to which examinations on different days affected the results when a standardized protocol was used was investigated. The repeatability of distal limb kinematics in nine sound horses over three successive days at one location was investigated. Measurements were performed at the examination area, for three motion cycles at the walk and trot, in each direction per day. Skin markers were placed on the lateral aspect of the coffin joint, forelimb fetlock joint, hindlimb fetlock joint, carpus, tarsus, elbow, and stifle, at clipped sites marked with a permanent marker. The inter-day repeatability of angular measurements of the carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints was determined. A low degree of inter-day repeatability was found with statistically significant (P ≤ .05) differences between findings on different days, observed in the time-angle diagrams of left and right carpus, tarsus, forelimb fetlock, and hindlimb fetlock joints of all horses, at both walk and trot. The standardized Equinalysis Elite system for gait analysis of distal limb kinematics in the horse did not provide highly repeatable data in this setting.     

The forelimb in walking horses: 1. Kinematics and ground reaction forces

Video (60 Hz) and force (2000 Hz) data were collected from 5 sound horses during walking. Forelimb data were analysed for 8 strides (4 left, 4 right) per horse to determine sagittal plane kinematics and ground reaction forces (GRFs). The results suggested that brachial rotation was responsible for protraction and retraction of the limb as a whole, while rotations of the scapula and antebrachium elevated the distal limb during breakover and early swing then lowered it in preparation for ground contact. The coffin joint was flexed maximally at the time of peak longitudinal braking force, which occurred during breakover of the contralateral forelimb. The metacarpus was vertical at 28% stride. This was considerably earlier than the change from a braking to a propulsive longitudinal force (34% stride), which coincided with maximal extension of the fetlock joint. The longitudinal propulsive force peaked just after contact of the contralateral forelimb. During the swing phase the joints distal to the shoulder showed a single flexion cycle that peaked at 76% stride at the carpus, 81% stride at the fetlock and 84% stride at the elbow and coffin joints. The coffin and shoulder joints began to extend in the terminal swing phase and continued to extend through ground contact and early stance. The results provide normative data that will be applied in detecting changes in kinematics and ground reaction forces that are associated with specific lamenesses.     

Impact of walking surface on the range of motion of equine distal limb joints for rehabilitation purposes

The aim of this study was to evaluate the effect of three footing surfaces on the flexion/extension, and range of motion (ROM) of the carpus, tarsus and fetlocks in the horse. The percentage of stride spent in the stance phase of sound horses at the walk was also measured. Nine sound horses were walked on hard ground (HD), soft ground (SF) and a land treadmill (LT), and five complete gait cycles were recorded by a digital video camera. Retro-reflective markers were placed on the skin at four anatomical locations on the left fore and hind limbs, and data were analyzed using two-dimensional (2D) motion-analysis software. Maximal flexion/extension angles and range of motion were calculated for each joint, and the percentage of the stride spent in stance phase was determined for each stride.Maximal flexion of the tarsus and hind fetlock was greater on LT and SF compared to HD, while maximal flexion of the carpus was greater on LT compared to HD and SF. Maximal extension of the carpus was greater on HD compared to SF and LT, maximal extension of the tarsus was greater on HD and SF compared to LT, and maximal extension of the forelimb and hind limb fetlocks was greater on LT compared to HD and SF. The greatest overall ROM of the carpus and fetlocks was achieved on LT, while the greatest overall ROM of the tarsus was achieved on SF. The stance percentage of the stride for the hind limb was significantly different between all surfaces. In conclusion, walking surface influences flexion/extension of the carpus, tarsus and fetlocks in healthy horses, which should be considered when walking equine rehabilitation cases.     

Hyperextension of fetlock joints in German Holstein and German Holstein-Limousin crossbred calves

In two different dairy farms six calves exhibiting bilateral flexion of the fetlock joints in front or rear legs were born in 2000 to 2002. Four of the affected calves from the same farm were crossbred between German Holstein cows with red and white coat colour and a bull of the breed Limousin. The other two affected calves born on another farm were purebred German Holsteins with a black and white coat colour. The tests for BVD virus antigen and antibodies were negative in all affected calves. Three of the calves showed a lower selen and a higher glutamate dehydrogenase concentration in the analyses of blood metabolites. Two crossbred calves showed a degeneration of the liver with a progressive periportal fibrosis in a histological examination. In one calf an edema of astrocytes of the central nervous system was seen. The analysis of the pedigrees revealed for the four crossbred calves the Limousin bull as common ancestor and the mothers of the calves as relatives. For the affected purebred German Holstein calves also a sire was identified as a common ancestor. The pedigrees support inheritance through a monogenic autosomal recessive locus or more recessive gene loci with variable expressivity. However, the analysis could not clarify whether different gene loci are responsible for the congenital anomalies observed in the calves from the two farms and thus, the observed anomalies may be different genetic entities. Obvious environmental reasons were not found.     

Quantitative analysis of computer-averaged electromyographic profiles of intrinsic limb muscles in ponies at the walk.

The function of several intrinsic muscles of the fore-and hind limbs of 5 ponies walking normally was evaluated via surface electromyography. Electromyographic signals were band-pass filtered, rectified, linear enveloped, and standardized to the stride duration. Mean data from the muscles of the left and right limbs that were obtained from at least 30 strides in 2 recording sessions were recorded as electromyographic signals-time curves. The timing of muscle activity was determined from these graphs. On the basis of the major peaks in the electromyographic signal, muscle functions were identified. In the forelimb, the extensor carpi radialis muscle was involved in extension of the carpus at the end of the swing phase of the stride, and it provided support to flexion of the cubital joint at the beginning of the swing phase. The common digital extensor muscle extended the distal joints of the forelimb at the end of the swing phase. The ulnaris lateralis muscle provided support to extension of the cubital joint at the beginning of the stance phase, and the flexor carpi radialis muscle flexed the carpus at the beginning of the swing phase. The flexor carpi ulnaris muscle extended the cubital joint at the end of the swing phase. In the hind limb, the long digital extensor muscle flexed the tarsus at the beginning of the swing phase and extended the digital joints preceding the stance phase. The deep digital flexor muscle prevented overextension of the distal interphalangeal joint during the stance phase and flexion of the digital joints during the swing phase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in kinematic variables observed during pressure-induced forelimb lameness in adult horses trotting on a treadmill

OBJECTIVE: To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure. ANIMALS: 10 adult Quarter Horses. PROCEDURE: A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill. RESULTS: The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase. CONCLUSION AND CLINICAL RELEVANCE: Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe.     

Ultrasonographic examination of the carpal region in cattle--normal appearance

The carpal region was examined ultrasonographically in 18 healthy cattle (14 cows, 4 bull calves) and five bovine cadavers in order to determine the normal appearance of the carpal soft tissues using 7.5 MHz linear transducers.The course of the echogenic flexor and extensor tendons over the carpus and the joint spaces interposed between the articular bone surfaces were successfully imaged in all carpi. The palmar vessels were easily visualized in live animals. The lumina of carpal tendon sheaths and the boundaries of the carpal joint pouches could not be defined. Small anechoic fluid filled areas were visualized only at the level of the joint spaces. After experimental filling, the distended synovial cavities were imaged as well demarcated anechoic areas. The cross-sectional diameters of the extensor tendons, width of the palmar joint pouches and intraluminal diameters of the palmar vessels were measured.The results presented serve as reference data for ultrasonographic investigation of disorders of the bovine carpus.     

Effects of athletic taping of the fetlock on distal limb mechanics

REASONS FOR PERFORMING STUDY: Athletic taping is used frequently by human athletes to stabilise, maintain or strengthen soft tissue structures, but empirical evidence supporting any changes in equine kinematics is lacking. OBJECTIVES: To assess the effects of athletic taping of the fetlock applied by an experienced athletic trainer on forelimb mechanics in healthy horses. HYPOTHESES: That athletic taping of the distal forelimb reduces 1) hyperextension of the fetlock joint during stance, 2) flexion of the fetlock joint during swing and 3) ground reaction forces during stance. METHODS: Ground reaction force and kinematic data were obtained for 6 healthy horses trotting at 3 m/sec for 4 sequential conditions (baseline, untaped; pre-exercise, taped; post exercise, taped post 30 mins trotting exercise; transfer, 4 h after tape removal). Data were analysed using 2-way mixed ANOVAs (condition; joint). RESULTS: A statistically significant interaction was identified for the fetlock during the swing phase (mean +/- s.d. peak flexion at baseline 157 +/- 4 degrees, reduced with taping to 172 +/- 4 degrees; P<0.05) compared with no differences across conditions for the other joints. Peak vertical force reduced significantly (P<0.05) with taping. CONCLUSIONS: Athletic taping of the fetlock does not alter the kinematics of the forelimb during stance, but does limit flexion of the fetlock during the swing phase. The decreased peak vertical force may be due to an increased proprioceptive effect. POTENTIAL RELEVANCE: Reduced peak vertical forces may be of benefit in preventing or reducing injury. Further investigation remains necessary before it can be concluded that taping should be applied for tendinous or ligamentous rehabilitation in equine patients.     

Arthroscopic visualisation of the third metacarpal and metatarsal condyles in the horse

Reasons for performing study: Arthroscopy of the fetlock joints is a routine surgical procedure in the horse. It is unclear how much of the articular surface of the condyles of the metacarpal (MCIII)/metatarsal (MTIII) bone can be visualised using either the dorsal or palmar/plantar arthroscopic approach. Objectives: To investigate which part of the articular surface of the MCIII/MTIII condyles of the fetlock joints can be evaluated arthroscopically using: 1) dorsal approach in combination with flexion; 2) standard palmar/plantar approach; or 3) additional portal at the base of the sesamoid bone with joint extension. Methods: All 3 arthroscopic approaches were performed on 20 fore‐ and 20 hindlimbs of 14 cadavers. For each approach, a curette was inserted ipsilaterally to create a lesion at the most distal part of the condyle that could be seen. After disarticulation and placement of a nail in each lesion, the maximally reachable angle was calculated on a perfect lateromedial radiograph. The 0° angle was determined as the distal crossing of the best fitting circle around the condyle with a line parallel to the dorsal MCIII/MTIII bone running through the circle centre (positive angle dorsal to 0°, negative palmar/plantar to 0°). Results: Using the dorsal approach with flexion, a significantly larger area of visualisation was present in the hind‐ (?23.4°) compared to the forelimb (+2.7°). Using the palmar/plantar approach (fore: ?60.4°; hind: ?70.7°) and the approach at the base of the sesamoid bone (fore: ?36.3°; hind: ?47.6°) more cartilage could be seen in the fore‐ compared to the hindlimb. When combining the 3 approaches, the remaining nonvisible part measured 38.9° in the fore‐ and 24.2° in the hindlimb, both located palmaro/plantarodistally. Conclusions: The use of dorsal and palmar/plantar arthroscopic approaches in combination with flexion and extension of the fetlock joint allows visualisation of the majority of the cartilage of the MCIII/MTIII condyles. The nonvisible section is smaller in the hindlimb compared to the forelimb. Potential relevance: Knowledge of the specific areas of visualisation of the condyles on arthroscopy is important for both diagnostic and therapeutic planning of fetlock disorders.     

Association of Ultrasound and Anatomopathologic Findings of Equine Metacarpophalangeal Lesions

To determine the association between ultrasonographic (US) and anatomopathologic findings, an US examination was performed postmortem on the fetlock and associated structures of 37 equine forelimb specimens. All these specimens exhibited images suggestive of lesions on the ultrasound examination. Subsequently, these limbs were dissected and underwent an anatomopathologic study. Ultrasonographic changes in size, shape, architecture, and echogenicity of ligaments, tendons, joint capsule, articular cartilage, and bony surfaces of the metacarpophalangeal joint were associated with the anatomopathologic findings.     

The forelimb in walking horses: 2. Net joint moments and joint powers

The objective was to measure the net joint moments and joint powers for the joints of the equine forelimb during the walk. Videographic and force data were combined with morphometric information using an inverse dynamics method. During stance phase the predominant joint moment was on the palmar aspect of all forelimb joints except the shoulder, where the peak moment was considerably higher than at any other joint. The entire forelimb showed net energy absorption in both stance and swing phases. The elbow was the only joint that showed net generation of energy, which was used to maintain the limb in extension in early stance as the horse's body vaults over the limb and to drive protraction and retraction of the limb during swing. The carpus aligned the limb into a supportive strut, but did not play an important role in energy absorption or generation. A small burst of positive work on the flexor aspect at the start of breakover indicated that the carpus played an active role in initiating breakover during walking. The fetlock functioned elastically to store and release strain energy during stance. The coffin joint acted as an energy damper during most of stance with a small burst of energy generation on the flexor aspect as the joint flexed during breakover. The magnitude of the peak joint power during swing decreased in a proximal to distal sequence. It is concluded that the elbow joint is the main site of energy generation. The shoulder and coffin joints act as energy dampers during stance. The distal joints had very low joint powers and appeared to be driven by inertial forces during the swing phase. This information will be applied to describe how horses compensate for different lamenesses in terms of redistributing the functions of energy generation and absorption between joints.     

Effects of balancing and shoeing of the forelimb feet on kinematic gait analysis in five horses with navicular disease

The effects of balancing the foot and shoeing (B&S) on the kinematics of five Quarter Horses with navicular disease were evaluated using computerized gait analysis. Kinematic measurements of the right forelimb and head were made before and after palmar digital nerve block (PDNB) and before and after B&S of the forelimb feet. Carpal and fetlock joint angle, foot displacement, and temporal gait measurements were made for at least five strides in each horse trotting on a treadmill. Kinematic measurements were compared before and after PDNB and before and after B&S by analysis of variance with an α=0.05. The most significant kinematic changes seen after PDNB were in the vertical head movement parameters studied. Total vertical head excursion and measures of head height asymmetry between right and left forelimb stance phases decreased after PDNB. After B&S mean carpal flexion and maximum hoof height during the swing phase of the stride increased, but none of the head movement parameters significantly changed. Results of this study indicate that the ability of treadmill kinematic gait analysis to evaluate for improvement in lameness by monitoring vertical head movement parameters is not significantly affected in horses with navicular disease three weeks after balancing and shoeing the forelimb feet.     

Neoplasms in cattle: A survey of 372 neoplasms examined at the Ruakura Veterinary Diagnostic Station

Intra-articular sodium hyaluronate was used to treat 16 horses with osteo-arthrosis of the carpus, fetlock, hock and coffin joints. In 11of these horses lameness was completely relieved. In addition, 5 horses that underwent carpal surgery for the removal of chip fractures received sodium hyaluronate 10–14 days later. In thesecases, it appeared to have a beneficial effect, resulting in a greater range of movement of the carpus soon after surgery and less swelling of the joint capsule. The results of synovial fluid analysis in horses with osteo-arthrosis, and with carpal fractures, are also presented.     

Forelimb Conformation,Sales Results,and Lifetime Racing Performance of 2-Year-Old Thoroughbred Racing Prospects Sold at Auction

To determine associations between carpal and fetlock conformation and later performance, 292 two-year-old (2YO) Thoroughbred horses were examined at a public auction. Two observers graded carpal and fetlock conformation in the frontal view, and subject weights were estimated (weight tape), and height was measured. Subject age, gender, and workout distance and time were retrieved from sales data. Lifetime racing data was retrieved from the Jockey Club database. Mild to moderate deviations from straight forelimb conformation at the carpus or fetlock occurred in 85% of 2YO Thoroughbreds and had no substantive effect on lifetime racing performance. Carpal and fetlock conformation are associated. Greater age, female gender and faster workout were associated with better short and long-term racing outcomes. The ability to start a race at 2YO was associated with improvements in several measures of racing success. The lack of an association of forelimb conformation with most measures of racing performance will assist producers and consumers of young racing stock in the determination of the need for corrective procedures in young horses and the importance of deviations at purchase. Speed of workout and the ability to start at 2YO were associated with each other and with an improvement in several racing outcomes.     

Tissue engineering: new treatment of cartilage alterations in degenerative joint diseases in horses--preliminary results of a long term study

Degenerative alterations in fetlock joints of the forelimb are common diagnoses for horses. The hyaline cartilage has a low capacity to regenerate and the treatment by veterinarians is often insufficient. As a final result, horses with articular cartilage defects are often not able to take part in competitions anymore. To establish an autologous cartilage repair method, we set artificial lesions (8 mm in diameter) into the fetlock joints of the forelimb of three horses. These defects were closed with autologous chondrocyte implants, which were fixed with titan-suture-anchors. After 3, 12 and 24 months, biopsies were taken by arthroscopy. One horse was euthanized after 9, another one after 24 months. The repair tissue was examined histologically and by biochemical analysis of hydroxyproline and glycosaminoglycan, which are typical cartilage related substances. After 9 months, the integration of the implant into native cartilage was demonstrated by electron microscopy. After 24 months, histological staining showed a similar morphology of the cartilage repair tissue compared with the surrounding native cartilage. Biochemical analysis of typical cartilage matrix molecules revealed formation of hyaline-like cartilage within tissue engineered autologous chondrocyte transplants.     

Carpal hyperextension in a Percheron mare caused by a palmar carpal ligament tear

A Percheron mare was presented for acute, severe lameness and marked swelling of the right forelimb after being cast. The mare was initially diagnosed with cellulitis of the forelimb but as her condition improved and the affected limb was able to bear more weight it became apparent that the limb was hyperextended at the level of the carpus. Widening of the palmar aspect of the middle carpal joint was observed radiographically. During ultrasonographic examination, excessive fluid in the carpal sheath and perithecal swelling were noted and tearing of the palmar carpal ligament was suspected. A dynamic brace was fabricated to prevent hyperextension of the carpus. After discontinuation of systemic antibiotics, the mare became febrile and forelimb lameness worsened. Cytology of fluid from the middle carpal joint confirmed joint sepsis and the mare was anaesthetised for arthroscopic examination. A tear in the palmar carpal ligament, characterised by focal fibre disruption and fibrillation, was identified during arthroscopic and tenoscopic examination. Communication between the carpal flexor tendon sheath and middle carpal joint was identified during these procedures. Both the middle carpal joint and carpal flexor tendon sheath were lavaged with physiological saline solution. Post operatively, swelling and lameness slowly resolved. Four months after discharge, the mare was sufficiently sound to be maintained at pasture. Viewed from its lateral aspect, the limb no longer appeared to be hyperextended from the carpus.     

Detection of lameness and determination of the affected forelimb in horses by use of continuous wavelet transformation and neural network classification of kinematic data

OBJECTIVE: To investigate continuous wavelet transformation and neural network classification of gait data for detecting forelimb lameness in horses. ANIMALS: 12 adult horses with mild forelimb lameness. PROCEDURE: Position of the head and right forelimb foot, metacarpophalangeal (ie, fetlock), carpal, and elbow joints was determined by use of kinematic analysis before and after palmar digital nerve blocks. We obtained 8 recordings from horses without lameness, 8 with right forelimb lameness, and 8 with left forelimb lameness. Vertical and horizontal position of the head and vertical position of the foot, fetlock, carpal, and elbow joints were processed by continuous wavelet transformation. Feature vectors were created from the transformed signals and a neural network trained with data from 6 horses, which was then tested on the remaining 2 horses for each category until each horse was used twice for training and testing. Correct classification percentage (CCP) was calculated for each combination of gait signals tested. RESULTS: Wavelet-transformed vertical position of the head and right forelimb foot had greater CCP (85%) than untransformed data (21%). Adding data from the fetlock, carpal, or elbow joints did not improve CCP over that for the head and foot alone. CONCLUSIONS AND CLINICAL RELEVANCE: Wavelet transformation of gait data extracts information that is important for the detection and differentiation of forelimb lameness of horses. All of the necessary information to detect lameness and differentiate the side of lameness can be obtained by observation of vertical head movement in concert with movement of the foot of 1 forelimb.     

Observations on the in vitro behavior of digital tendons

The force/strain behavior of the common and lateral extensor tendons, the extensor branches of the interosseus muscle, and the superficial flexor tendon have been examined in vitro. The flexor tendon acted as a hard-spring with an initial large strain with small load followed by progressively less strain with increasing load, The distal part of the common extensor tendon and the extensor branches behaved in the same manner during dorsiflexion of the fetlock joint/palmar flexion of the coffin joint. The common extensor tendon behaved in a softening manner during palmar flexion of the fetlock and coffin joints while the lateral extensor and the extensor branches behaved in a nearly linear manner.     

Kinematic characteristics of Andalusian, Arabian and Anglo-Arabian horses: a comparative study

The aim of this study was to compare the kinematic trot characteristics of three different breeds of horse: Andalusian (AN, n = 15), Arabian (AR, n = 7) and Anglo-Arabian (AA, n = 5) using standard computer-assisted videography (25 Hz). Linear, temporal and angular parameters in fore- and hind limbs were analysed in six randomly selected strides per horse. Normalised angle-time diagrams along the complete stride were obtained for all joints angles in each breed and specific kinematic characteristics were detected graphically. AA horses displayed longer swing durations in both limbs ans a shorter angular range of motion (ARM) in scapula and pelvis inclination and in shoulder, hip and forelimb retraction-protraction angles. At lift off, stifle and tarsal joint angles were more flexed. In general, only small differences were observed in AR horse kinematics when compared with the other 2 breeds. AN horses presented negative overtracking length, which was positive in AR and AA. In AN horses the elbow and carpal joints were more flexed at the moment of maximal elevation, elbow and fore-fetlock joints also exhibited a larger ARM due to a smaller angle at maximal flexion. In the hind limbs, tarsal, hind fetlock and retraction-protraction angles presented a larger ARM in AN horses due to greater maximal flexion in the tarsal and hind fetlock joints. Fore- and hind fetlocks were also more flexed in horses from this breed. In conclusion, differences between kinematic variables at the trot were observed in the three breeds studied here, mainly in forelimb joints. The most outstanding feature was the greater forelimb flexion recorded in AN horses than in the other breeds which is consistent with the elevated movements in this breed. In AA horses, the ARM of proximal joints involved in retraction protraction in both fore- and hind limbs was smaller. All the differences observed highlighted the idiosyncratic nature of the trot in each breed; this may influence the functional capacity of each breed.