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Abstract

Objective—To study the effect of unilateral synovitis in the distal intertarsal and tarsometatarsal joints on locomotion, including the compensating effects within and between limbs.

Animals—4 clinically normal horses.

Procedure—Gait analyses including kinematics, force plate, and inverse dynamic analysis were performed at the trot before lameness, after which synovitis was induced by injecting endotoxin into the right distal intertarsal and tarsometatarsal joints. Gait analyses were repeated 24 to 30 hours later during lameness. Differences between the stride variables during the 2 conditions (lame and sound) were identified.

Results—Tarsal joint range of motion, peak vertical force, and vertical impulse were decreased during lameness. Mechanical deficits included a decrease in negative work performed by the tarsal extensors during the early stance phase and a decrease in positive work by the tarsal extensors during push off. No compensatory changes in work were performed by other joints within the lame hind limb during the stance phase. Vertical impulse in the diagonal forelimb decreased, but there were no significant changes in forces or impulses in the ipsilateral forelimb or contralateral hind limb.

Conclusions and Clinical Relevance—Results indicate that horses are able to manage mild, unilateral hind limb lameness by reducing the airborne phase of the stride rather than by increased loading of the compensating limbs. (Am J Vet Res 2003;64:1491–1495)

Full access
in American Journal of Veterinary Research

Abstract

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. (Am J Vet Res 2000;61:191–196)

Full access
in American Journal of Veterinary Research

Abstract

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. (Am J Vet Res 2000;61:197–201)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether body lean angle could be predicted from circle radius and speed in horses during lunging and whether an increase in that angle would decrease the degree of movement symmetry (MS).

Animals—11 medium- to high-level dressage horses in competition training.

Procedures—Body lean angle, head MS, and trunk MS were quantified during trotting while horses were instrumented with a 5-sensor global positioning system–enhanced inertial sensor system and lunged on a soft surface. Speed and circle radius were varied and used to calculate predicted body lean angle. Agreement between observed and predicted values was assessed, and the association between lean angle and MS was determined via least squares linear regression.

Results—162 trials totaling 3,368 strides (mean, 21 strides/trial) representing trotting speeds of 1.5 to 4.7 m/s and circle radii of 1.8 to 11.2 m were conducted in both lunging directions. Differences between observed and predicted lean angles were small (mean ± SD difference, −1.2 ± 2.4°) but significantly greater for circling to the right versus left. Movement symmetry values had a larger spread for the head than for the pelvis, and values of all but 1 MS variable changed with body lean angle.

Conclusions and Clinical Relevance—Body lean angle agreed well with predictions from gravitational and centripetal forces, but differences observed between lunging directions emphasize the need to investigate other factors that might influence this variable. For a fair comparison of MS between directions, body lean angle needs to be controlled for or corrected with the regression equations. Whether the regression equations need to be adapted for lame horses requires additional investigation.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To calculate normative joint moments of force and power for the forelimb of walking horses as a benchmark against which to compare these mechanical variables in horses with specific lameness.

Animals

4 Dutch Warmblood horses with no recent history of lameness.

Procedure

Horses were walked by hand through the test area, and data from 5 walking trials were collected for each horse. Two camera views were combined with vertical and craniocaudal ground reaction forces to calculate net moments of force in the sagittal plane across the carpal, metacarpophalangeal (fetlock), and distal interphalangeal (coffin) joints during the stance phase of the forelimb. Mechanical power was calculated as the product of net joint moment and the joint's angular velocity.

Results

During the early part of the stance phase, the carpal joint had oscillating periods of energy generation and absorption against a predominant flexor moment, then an absorption phase at the end of the stance phase, as the carpus flexed into swing against an extensor moment. The fetlock absorbed energy in the early part of the stance phase, then the terminal part was marked by a large generation of energy across the joint. A flexor moment was measured at the coffin joint throughout the stance phase, and this coincided with a long phase of energy absorption followed by a short phase of generation for push-off.

Conclusion

Consistency of the power data indicates that typical profiles of work exist for each of the joints (carpus, fetlock, and coffin).

Clinical Relevance

Detection of changes to these profiles of work may contribute to diagnosis of specific lameness conditions.(Am J Vet Res 1998;59:609–614)

Free access
in American Journal of Veterinary Research