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  • Author or Editor: Philippe Pourcelot x
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Abstract

Objective

To evaluate asymmetry in placement of bilateral skin markers on horses and to determine effect of asymmetric skin marker placement on kinematic variables for trotting horses.

Animals

10 horses for evaluation of asymmetry in marker placement; 1 horse for evaluation of effects on kinematic variables.

Procedure

Asymmetry in marker placement was assessed by attaching markers to horses and comparing radiographs of left and right limbs. An experimental model was developed to determine effects on kinematic variables; accuracy of the model was validated experimentally. Using kinematic data from a clinically normal trotting horse as reference data, effects of asymmetric marker placement on vertical displacement-time and joint angle-time diagrams were determined by use of the model.

Results

Asymmetry of placement was < 1 cm for markers on the distal portions of the limbs and < 2 cm for markers on the proximal portions. Asymmetric marker placement did not alter general shapes of the vertical displacement-time and joint angle-time curves. In most instances, largest differences in vertical displacement attributable to asymmetric marker placement were equal to or less than magnitude of the asymmetry of placement. Alterations in joint angle-time curves were mainly a result of shifting of the curves on the Y axis. Joint range of motion was only slightly changed by asymmetric marker placement, but maximum flexion and extension angles were greatly altered.

Conclusions and Clinical Relevance

Some kinematic variables can be greatly altered by small differences in skin marker placement. Such effects should be taken into account when evaluating kinematic data for sound and lame horses. (Am J Vet Res 1998;59:938–944)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine the local variations of mechanical properties of the equine superficial digital flexor tendon (SDFT).

Sample Population

10 SDFT of adult horses, selected for absence of abnormality.

Procedure

Needles (with a dark marker at both ends) pinned perpendicularly through each tendon to delimit 7 segments. Each tendon was tested in traction until rupture; test was filmed, using an 8-mm video camera. For each image, the coordinates of the center of mass of each marker and the corresponding force were registered. The third-degree polynomial that best fits the stress-strain curve thus obtained was calculated by a least squares approximation. The modulus of elasticity (Emax) of each segment was evaluated as the maximum of the derivative of this polynomial.

Results

Mean rupture load of the 10 SDFT was 12,356 ± 1,333 N. The strain at tendon rupture and Emaxvaried, respectively, from 8.1 ± 1.3% and 1,002 ± 161 MPa (sesamoidean region) to 12.5 ± 1.7% and 1,189 ± 63 MPa (metacarpal region). The values of the strain corresponding to Emax were remarkably similar along the SDFT (approx 5%).

Conclusions

Emax appeared fairly homogeneous along an SDFT, although being slightly higher in the metacarpal region. The 5% strain corresponding to Emax could be the limit strain beyond which microlesions of the tendinous fibers begin to appear, this threshold being first reached during the traction test by the metacarpal segments. (Am J Vet Res 1996;57:1111–1117)

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the effect of track surface firmness on the development of musculoskeletal injuries in French Trotters during 4 months of race training.

ANIMALS 12 healthy 3-year-old French Trotters.

PROCEDURES Horses were paired on the basis of sex and body mass. Horses within each pair were randomly assigned to either a hard-track or soft-track group. The counterclockwise training protocol was the same for both groups. Surface firmness of each track was monitored throughout the training period. Radiography, ultrasonography, MRI, and scintigraphy were performed on all 4 limbs of each horse before and after 2 and 4 months of training. Lesions were described, and lesion severity was classified with a 5-point system, where 0 = no lesions and 4 = severe lesion.

RESULTS 86 lesions were identified, of which 46 (53.5%) were classified as potentially clinically relevant (grade, ≥ 2). Of the 18 moderate and severe lesions, 15 were identified in horses of the hard-track group, and 10 of those were in forelimbs. Moderate to severe tendinopathy of the superficial digital flexor tendon of the forelimb developed in 3 of the 6 horses of the hard-track group but none of the horses of the soft-track group. Metatarsal condyle injuries were more frequent in horses of the hard-track group than horses of the soft-track group. Severe lesions were identified only in left limbs.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that track surface firmness is a risk factor for musculoskeletal injuries in horses trained for harness racing.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To assess histologic variations of the equine superficial digital flexor tendon (SDFT) according to site and to horse age and activity, and to correlate these data with reported segmental mechanical results.

Sample Population

Superficial digital flexor tendons isolated from 42 horses 0.5 hour to 23 years old.

Procedure

7 segments of each SDFT were delimited and submitted for conventional histologic examination. Each segment was examined and graded for fiber undulation, cellularity, number and size of interfascicular connective spaces (ICS), presence or absence of focal and diffuse chondroid metaplasia, and differentiation of the dorsal (DB) and palmar (PB) borders of the tendon.

Results

Fiber undulation and cellularity significantly decreased with age. The proximal and middle metacarpal segment fibers were significantly less undulated and their ICS were smaller than those of the other segments, especially in old horses. Focal chondroid metaplasia developed from 5 years onward, mainly in the sesamoidean segments. Diffuse chondroid metaplasia was characteristic of the digital region in horses > 6 years old. The DB of the metacarpodigital region tended to differentiate into fibrocartilage in association with age. The PB was generally differentiated as nonfascicular dense connective tissue. Activity induced a decrease in the number and size of the ICS.

Conclusions

The lesser undulation of the proximal and middle metacarpal segments fibers can be correlated to their mechanical behavior (stress-strain curve) and relative weakness within the SDFT. Focal chondroid metaplasia and fibrocartilage on the DB are normal features, related to the compression stresses undergone by the sesamoidean region of the tendon. (Am J Vet Res 1998;59:969–977)

Free access
in American Journal of Veterinary Research