Joint angle, moment and power compensations in dogs with fragmented medial coronoid process

Fragmented medial coronoid process (FMCP) is the most common cause of forelimb lameness in juvenile medium and large breed dogs; however methods of assessing the disruption to their gait remain subjective. The purpose of this study was to objectively quantify the mechanical disruptions to gait in dogs with arthroscopically confirmed unilateral FMCP. Seven dogs underwent full inverse dynamic analysis at the time of diagnosis. Kinematic and force data were collected from both forelimbs at trot. Stance phase joint angles, net joint moments and net joint powers were calculated using custom software. There were gross differences in kinetic and kinematic patterns between FMCP affected and compensating forelimbs. Stance time was 0.24 sec on the lame side and 0.26 sec on the compensating side. The shoulder and the elbow were more flexed at ground contact, and elbow, carpal and MCP joints had smaller ranges of motion on the lame side. Net joint moments were significantly reduced (P < 0.05) in the elbow, carpal and MCP joints of the FMCP affected limb. Net joint powers were likewise significantly smaller (P < 0.05). However, the overall moment and power patterns persisted. Total limb support moment was significantly smaller on the affected side (P < 0.05). Total limb power was significantly reduced on the affected side (P < 0.05) being most affected in its propulsive phase in the second half of stance. Inverse dynamic analysis of this clinical condition is an objective means by which to assess the mechanical disruption to gait.     

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.     

Distribution of power across the hind limb joints in Labrador Retrievers and Greyhounds

OBJECTIVE: To quantify angular excursions; net joint moments; and powers across the stifle, tarsal, and metatarsophalangeal (MTP) joints in Labrador Retrievers and Greyhounds and investigate differences in joint mechanics between these 2 breeds of dogs. ANIMALS: 12 clinically normal dogs (6 Greyhounds and 6 Labrador Retrievers) with no history of hind limb lameness. PROCEDURE: Small retroreflective markers were applied to the skin over the pelvic limb joints, and a 4-camera kinematic system captured data at 200 Hz in tandem with force platform data while the dogs trotted on a runway. Breed-specific morphometric data were combined with kinematic and force data in an inverse-dynamics solution for stance-phase net joint moments and powers at the stifle, tarsal, and MTP joints. RESULTS: There were gross differences in kinematic patterns between Greyhounds and Labradors. At the stifle and tarsal joints, moment and power patterns were similar in shape, but amplitudes were larger for the Greyhounds. The MTP joint was a net absorber of energy, and this was greater in the Greyhounds. Greyhounds had a positive phase across the stifle, tarsal, and MTP joints at the end of stance for an active push-off, whereas for the Labrador Retrievers, the only positive phase was across the tarsus, and this was small, compared with values for the Greyhounds. CONCLUSIONS AND CLINICAL RELEVANCE: Gross differences in pelvic limb mechanics are evident between Greyhounds and Labrador Retrievers. Joint kinetics in specific dogs should be compared against breed-specific patterns.     

Effect of trotting velocity on work patterns of the hind limbs of Greyhounds

OBJECTIVE: To quantify the effects of trotting velocity on joint angular excursions, net joint moments, and powers across the hind limb joints in Greyhounds. ANIMALS: 5 healthy Greyhounds with no history of lameness of the hind limbs. PROCEDURES: Small reflective markers were applied to the skin over the joints of the hind limbs, and a 4-camera kinematic system was used to record positional data at 200 Hz in tandem with force platform data while the dogs trotted on a runway at slow, medium, and fast velocities. Breed-specific morphometric data were combined with kinematic and force data in an inverse-dynamics solution for net joint moments and powers at the hip, stifle, tarsal, and metatarsophalangeal joints. RESULTS: Angle, moment, and power patterns at the various joints were conserved among the 3 velocities. With increasing velocity, moments and powers at the tarsal, stifle, and hip joints during the stance phase were increased in amplitude, whereas amplitudes during the swing phase were not. The main contributors to increased velocity were the hip extensors and stifle flexors during the early part of the stance phase and the tarsal extensors during the late part of the stance phase. CONCLUSIONS AND CLINICAL RELEVANCE: Increases in trotting velocity in Greyhounds do not alter the basic patterns of work and power for various joints of the hind limbs, but local burst amplitudes during the stance phase increase incrementally.     

Traumatic communication of the extensor carpi radialis tendon sheath and antebrachiocarpal joint in two horses

Two horses were examined due to lacerations at the level of the craniodistal antebrachii. Further evaluation of the lacerations revealed communication with the extensor carpi radialis tendon sheath and potentially the antebrachiocarpal joint. Positive contrast arthrography performed via the palmarolateral pouch of the antebrachiocarpal joint was used to diagnose communication with the extensor carpi radialis tendon sheath. Both the joints and tendon sheaths were treated aggressively with surgical debridement and lavage, followed by post operative medical management and rehabilitation. Both horses made a full recovery and are performing in their intended level of use with acceptable cosmetic results. Traumatic communication with the carpal joints should be considered when evaluating lacerations involving the forelimb extensor tendon sheaths.     

Horizontal moment around the hoof's centre of pressure during walking in a straight line

Reasons for performing study: Joint congruity and ligaments restrain the distal limb joints from excessive motion in the transverse and frontal planes, but the magnitudes and direction of the horizontal twisting moments around the hoof's centre of pressure (CoP) that induce these motions are unknown. Objectives: To quantify the horizontal moment around the vertical axis through the hoof's CoP at walk, and to determine whether these are symmetric. Methods: Nine sound Thoroughbred horses (mean age 5.3 years; mean mass 502 kg) were led at walk in a straight line across a Kistler force platform. Five trials were collected for each fore and hindlimb. The resultant moment around the hoof's CoP was calculated from the horizontal moment arms between the calculated CoP and the 4 horizontal forces in the transverse (X) and cranio‐caudal (Y) directions. Results: The calculated moments were consistent within limbs and horses, but variable between horses. Hindlimbs demonstrated a biphasic moment pattern and the largest moments were typically in the first half of stance. Mean ± s.d. peak moments were internal under both hindlimbs (L: Int 14.1 ± 4.6 Nm; R: Int 13.3 ± 5.5 Nm). In the forelimbs, 7/9 horses demonstrated an asymmetric moment pattern, with the left forelimb exerting an internal moment (L: Int 6.9 ± 2.9 Nm) and the right forelimb an external moment (R: Ext 8.4 ± 4.4 Nm), while the remaining 2 horses exerted internal moments in both forelimbs (L: Int 11.7 ± 1.4 Nm; R: Int 6.6 ± 1.9 Nm). Conclusion: In 7/9 horses, the forelimbs exerted asymmetric horizontal moments around the hoof CoP. The hindlimbs appear to behave with mechanical symmetry during stance, exerting an internal moment during retraction. Potential relevance: Extrasagittal joint motions in the forelimb are unlikely to be symmetric and future studies should account for possible bilateral variations.     

Moment arms about the carpal and metacarpophalangeal joints for flexor and extensor muscles in equine forelimbs

OBJECTIVE: To determine whether muscle moment arms at the carpal and metacarpophalangeal joints can be modeled as fixed-radius pulleys for the range of motion associated with the stance phase of the gait in equine forelimbs. SAMPLE POPULATION: 4 cadaveric forelimbs from 2 healthy Thoroughbreds. PROCEDURE: Thin wire cables were sutured at the musculotendinous junction of 9 forelimb muscles. The cables passed through eyelets at each muscle's origin, wrapped around single-turn potentiometers, and were loaded. Tendon excursions, measured as the changes in lengths of the cables, were recorded during manual rotation of the carpal (180 degrees to 70 degrees) and metacarpophalangeal (220 degrees to 110 degrees) joints. Extension of the metacarpophalangeal joint (180 degrees and 220 degrees) was forced with an independent loading frame. Joint angle was monitored with a calibrated potentiometer. Moment arms were calculated from the slopes of the muscle length versus joint angle curves. RESULTS: At the metacarpophalangeal joint, digital flexor muscle moment arms changed in magnitude by < or = 38% during metacarpophalangeal joint extension. Extensor muscle moment arms at the carpal and metacarpophalangeal joints also varied (< or = 41% at the carpus) over the range of joint motion associated with the stance phase of the gait. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings suggest that, apart from the carpal flexor muscles, muscle moment arms in equine forelimbs cannot be modeled as fixed-radius pulleys. Assuming that muscle moment arms at the carpal and metacarpophalangeal joints have constant magnitudes may lead to erroneous estimates of muscle forces in equine forelimbs.     

Horizontal moment around the hoof centre of pressure during walking on right and left circles

Reasons for performing study: Recent research indicates that the digital joints experience some degree of extrasagittal motion during stance and that the moments under the hoof are asymmetric in horses walking in a straight line. On a circle, these have not been defined. Objectives: To quantify the amplitude and symmetry of horizontal twisting moments around the vertical axis through the hoof's centre of pressure on left and right circles at walk. Methods: Six Thoroughbred horses were led at walk across a Kistler force platform on a left and a right circle of 5 m radius. The resultant moment around the hoof was calculated from the 4 horizontal forces and their moment arms. Results: Five of the 6 horses exerted an internal moment around their left forehoof, and 4 exerted an internal moment around their right forehoof on the left circle. On the right circle, 5 of the 6 exerted an internal moment around the left forehoof and a weak external moment around the right forehoof. The moments under the hind hooves were bilaterally similar for right and left circles. Conclusion: Intrahorse variability in the applied moments is low, but there is some interhorse variability, especially in the forelimb moments, that indicates future studies of movements of the distal limb joints should be bilateral to account for mechanical asymmetry. Potential relevance: The finding that horizontal moments vary between forelimbs in some horses will apply to how exercise on a circle is approached, especially in rehabilitation programmes for horses with orthopaedic injury of the distal limb.     

Net joint kinetics in the limbs of pigs walking on concrete floor in dry and contaminated conditions

In pigs (Sus scrofa), joint disorders are frequent leg problems, and inappropriate pigpen floors and slippery floor conditions may contribute to these problems. Therefore, this study first aimed to quantify the net joint kinetics (net joint moments and net joint reaction forces) in the forelimbs and hindlimbs of healthy pigs walking on solid concrete floors. Second, this study aimed to examine the effect of floor condition on the net joint kinetics. Kinematic (50-Hz video recordings) and kinetic (1-kHz force plate measurements) data were collected from 30 pigs and combined with body segment parameters from a cadaver study. Net joint kinetics was calculated by using a 2-dimensional inverse dynamic solution. Inverse dynamics have, to our knowledge, not been applied in pigs before. Dry, greasy, and wet floor conditions were tested with 10 pigs each. In the forelimbs, peak joint moment was less (P < 0.01) on greasy (0.184 +/- 0.012 Nm/kg, moment of force per kg of BW) than on dry (0.232 +/- 0.012 Nm/kg) or wet (0.230 +/- 0.012 Nm/kg) conditions. Additionally, the minimum forelimb joint moment was more negative (P < 0.05) on greasy (-0.119 +/- 0.009 Nm/kg) than on dry or wet (both -0.091 +/- 0.009 Nm/kg) conditions. The forelimb joint reaction forces and the hindlimb joint kinetics were unaffected by floor condition. The greatest (P < 0.001) joint moments occurred in the shoulder (-0.376 +/- 0.007 Nm/kg), elbow (0.345 +/- 0.009 Nm/kg), hip (0.252 +/- 0.009 Nm/kg), and tarsal (0.329 +/- 0.009 Nm/kg) joints, which may be related to the greater incidence of joint diseases in some of these joints. In conclusion, the forelimb joints of the pigs responded more markedly to floor condition than did their hindlimb joints, probably because the forelimbs carry more weight. In particular, between the dry and greasy floor conditions, the joint loading differed, most likely because the pigs adapted to a potentially slippery surface.     

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.     

Comparative motion analysis of the canine hind limb during gait on force plate and treadmill

Computer assisted gait analysis allows for the objective examination of ground reaction forces as well as the kinematic analysis of gait. At present it is unclear if there are relevant differences in the gait pattern of the hind limb of dogs during the walk on treadmill and force plate. Thus, aim of this study was the comparison of canine hind limb joint angles and certain kinematic gait cycle parameters like cadence, step and stride time as well as step length during the walk on force plate and treadmill. 19 adult dogs of different breeds were analysed. Extension and flexion of hip, stifle and hock, hip ab- and adduction and range of motion (ROM) were evaluated. Furthermore joint angles at the moment of maximum load were identified. Considering the joint angles and gait cycle parameters there were no significant differences between force plate and treadmill, except for the hip angles, the hock angle at the moment of maximum load as well as for cadence and stride time. Whereas all flexion/extension joint angles, except the maximum hock joint angle, showed a moderate to good correlation, the ROM of the analysed joint angles was in maximum moderate. In summary it could be demonstrated that the gait pattern of the canine hind limb shows similarities on force plate and treadmill. Nevertheless significant differences of certain parameters exist and in total only a fair to moderate correlation of the data between treadmill and force plate could be shown. Therefore the results of this study provide important information for the comparative interpretation of canine gait analysis carried out on force plates and treadmills.     

Net joint moments and joint powers in horses with superficial digital flexor tendinitis

OBJECTIVE: To determine whether analysis of net joint moments and joint powers is a suitable technique for evaluation of mechanics and energetics of lameness in horses and to measure effects of superficial digital flexor tendinitis. ANIMALS: 6 sound horses. PROCEDURE: Horses were evaluated before (sound evaluation) and after (lame evaluation) induction of superficial digital flexor tendinitis in 1 forelimb by injection of collagenase. Recordings were made with an optoelectronic system and a force plate as horses trotted. Net joint moments and joint powers in the sagittal plane at each joint in the forelimbs during the stance phase were determined. Peak values were determined, and mechanical energy absorbed and generated at each joint was calculated. Comparisons were made between contralateral limbs during sound and lame evaluations. RESULTS: Lame limbs had significant reductions in peak values for net joint moments on the palmar aspect of metacarpophalangeal (fetlock), carpal, and humeroulnar joints. Total energy absorbed was significantly lower at every joint in lame limbs, compared with compensating limbs. CONCLUSIONS AND CLINICAL RELEVANCE: Horses with superficial digital flexor tendinitis had significant differences between lame and compensating limbs for net joint moments and joint powers at all joints, indicating that the gait of horses with superficial digital flexor tendinitis is energetically inefficient. Assessment of net joint moments and joint powers is a useful tool in evaluating equine lameness.     

A Modified Cloward''s Technique for Arthrodesis of the Normal Metacarpophalangeal Joint in the Horse

A modified Cloward's technique was performed for arthrodesis of one metacarpophalangeal (MCP) joint in eight horses. Dorsal arthrotomies were performed medial and lateral to the common digital extensor tendon and two 16 mm holes were drilled through the joint. A perforated cylindrical stainless steel basket filled with cancellous bone was impacted into each hole. The limbs were supported in casts for 8 weeks. The joints were examined and radiographed at 4 weeks, 8 weeks, 6 months, and 10 months. One horse was euthanatized at week 14 to assess the progress of the arthrodesis. In the other seven horses, there was clinical fusion at month 6. Dynamographic evaluations were performed 11 months after surgery at the walk and trot. The maximum vertical forces exerted during weight bearing by treated and control limbs were compared. No difference was detected at the walk; however, a significant difference was present at the trot (p less than 0.05). It was calculated that at the trot the horses placed 90% as much force on the treated limb as on the control limb. Eleven months after surgery, the baskets contained compact and cancellous bone. Ingrowth of bone occurred through all openings, completely filling the baskets and fusing the joints.     

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.     

Compensatory load redistribution in naturally occurring osteoarthritis of the elbow joint and induced weight-bearing lameness of the forelimbs compared with clinically sound dogs

The current study investigated the compensatory load redistribution due to osteoarthritis of the elbow joint using ground reaction forces of all four legs, simultaneously measured on a treadmill with integrated force plates. Three groups of dogs were used: the first group was clinically sound; the second group suffered from a naturally occurring osteoarthritis of the elbow joint, and a reversible lameness was induced in the third group. The naturally occurring osteoarthritis resulted in a compensatory gait pattern to reduce the stress on the affected limb. The load was reduced on the lame limb and increased on the contralateral hindlimb. The symmetry index indicated a weight-shift to the contralateral forelimb and diagonal hindlimb, which resulted in a more balanced weight distribution than in normal dogs. Dogs with induced lameness showed comparable but less pronounced alterations. These results suggested that forelimb lameness could lead to overload on non-affected extremities and the vertebral spine.     

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.     

Effects of electrostimulated acupuncture on ground reaction forces and pain scores in dogs with chronic elbow joint arthritis

OBJECTIVE: To determine whether use of electrostimuluated acupuncture (ESA) would result in significant improvements in ground reaction forces and lameness scores in dogs with chronic elbow joint osteoarthritis secondary to elbow joint dysplasia. DESIGN: Randomized, controlled, crossover clinical trial. ANIMALS: 9 dogs with chronic forelimb lameness and radiographic evidence of elbow joint osteoarthritis. PROCEDURES: All dogs had a 3-week control acclimation period during which gait analysis was performed weekly. Dogs then received ESA once weekly for 3 weeks followed by a sham treatment once weekly for 3 weeks or received the sham treatment followed by ESA. Gait analysis was repeated prior to each treatment, and owners were asked to provide pain scores by use of a visual analog scale method. RESULTS: Treatment (control, acupuncture, or sham) did not have a significant effect on ground reaction forces for any limb. Owners of 8 of the 9 dogs were able to correctly guess the time period when ESA was delivered. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that ESA did not have any significant effects on severity of lameness, as determined by measurement of ground reaction forces, or severity of pain, as determined by visual analog scale pain scores, in dogs with chronic elbow joint osteoarthritis secondary to elbow joint dysplasia.     

Kinematics and ground reaction forces in horses with superficial digital flexor tendinitis

OBJECTIVE: To measure and correlate kinematic and ground reaction force (GRF) data in horses with superficial digital flexor tendinitis. ANIMALS: 6 sound horses. PROCEDURE: Horses were evaluated before (sound evaluation) and after (lame evaluation) induction of superficial digital flexor tendinitis in 1 forelimb (randomized) by injection of collagenase. As each horse trotted, kinematic data were collected by use of an optoelectronic system, and GRF data were measured by use of a force plate. Three-dimensional kinematic and GRF data were projected onto a 2-dimensional sagittal plane. RESULTS: Lame limbs had significantly lower peak vertical GRF, less flexion of the distal interphalangeal joint, and less extension of the metacarpophalangeal joint, compared with compensating limbs. Carpal joint kinematics did not change. Compensating limbs had a more protracted orientation throughout the stance phase and higher braking longitudinal force and impulse; however, total range of rotation from ground contact to lift off did not change. Transfer of body weight from lame to compensating limbs was smooth, without elevation of the body mass into a suspension phase. Propulsive components of longitudinal GRF did not differ between limbs. CONCLUSIONS AND CLINICAL RELEVANCE: In horses with experimentally induced superficial digital flexor tendinitis, changes in vertical GRF were reflected in angular excursions of the distal interphalangeal and metacarpophalangeal joints, whereas changes in longitudinal GRF were associated with alterations in the protraction-retraction angle of the entire limb.     

H-PSGAG concentration in the synovial fluid of the equine antebrachiocarpal, metacarpophalangeal, coronopedal and tibiotarsal joints following a 500 MG i

Eight mature horses were administered a single intramuscular injection of 500 mg polysulfated glycosaminoglycan (PSGAG) labeled with 2.044 mCi tritium. Synovial fluid samples were collected from the antebrachiocarpal (carpal), metacarpophalangeal (fetlock), tibiotarsal (hock) and coronopedal (coffin) joints prior to injection and at 2, 4, 8, 12, and 24 hours after injection. The samples were subjected to scintillation counting in decays per minute and were converted to μg PSGAG per ml. The levels achieved in the synovial fluid of the various joints were compared to levels of PSGAG described as adequate to inhibit enzymes which degrade articular cartilage matrix components and hyaluronic acid and adequate to stimulate production of new matrix components and hyaluronic acid in diseased joints.Mean synovial fluid ³H-PSGAG levels indicated that peak concentrations of ³H-PSGAG were achieved 2 hours post injection in all joints and that these concentrations were within the therapeutic range for PSGAG. The peak concentrations were not significantly different among the joints except between the antebrachiocarpal and the metacarpophalangeal joints. The areas under the concentration-time curves (AUC) for each joint were computed by the trapezoidal method from hour 0 through hour 24 and by empirical exponential decay beyond hour 24. These values were subjected to an analysis of variance (ANOVA). The overall multivariate test of AUC among all joints was not significant.The data from this study indicate that a single intramuscular 500 mg injection of PSGAG provided therapeutic levels of the drug in the equine antebrachiocarpal, metacarpophalangeal, tibiotarsal, and coronopedal joints within 2 hours of injection. While there were differences in levels between joints at certain time points, the AUC values suggest similar distribution of the drug in all joints tested.     

T-plate fixation of distal radial closing wedge osteotomies for treatment of angular limb deformities in 18 dogs

OBJECTIVE: To describe the surgical technique and clinical results of treatment for forelimb angular limb deformities, secondary to premature distal radial or ulnar physeal closure, by using T-plate fixation of a distal radial closing wedge osteotomy in 18 dogs. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: 18 client-owned dogs. METHODS: The medical records of 18 dogs that underwent a distal radial closing wedge osteotomy with T-plate fixation for correction of a forelimb angular limb deformity were reviewed. Small pins (Kirschner wires) were used to obtain the appropriate alignment of the antebrachiocarpal and elbow joints and proper limb orientation. In-hospital follow-up evaluation was obtained at the time fracture healing was observed radiographically. Further long-term follow-up was obtained by owner interview. RESULTS: Osteotomy sites were radiographically healed within 4 to 12 weeks (mean, 8 weeks) after surgery in the 14 dogs that returned for in-hospital follow-up. Limb function was graded as good or excellent in all dogs. Long-term follow-up by owner interview rated limb function and cosmetic appearance as good to excellent in all dogs. Plate removal was necessary in one dog 7 months after surgery because of osteopenia in the radius. CONCLUSION: This surgical technique was considered successful in the treatment of angular limb deformities in all dogs. A good to excellent prognosis is to be expected with this technique, with minimal complications. CLINICAL RELEVANCE: The use of a T-plate for the correction of angular limb deformities has not been previously described in the literature. This technique permits accurate correction of the angular limb deformity and minimizes postoperative complications.