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Summary

The medical records of 50 horses examined because of lacerations of the tendon of the superficial or deep digital flexor muscle were reviewed to determine whether any injury or treatment factors could be associated with outcome. Median age of horses treated was 4.5 years (range, 1.5 years to 15 years), and the median follow-up time was 5 years (range, 1.5 to 16 years) after injury. Horses were considered to have survived if they were alive more than 1 year after injury. Twelve of 16 horses that had 1 or the other tendon transected survived; 13 of 16 horses that had both tendons transected survived; and 14 of 18 horses that had partial tendon disruptions of 1 or both tendons survived. Of the 39 surviving horses, 27 horses returned to their original use, and 32 horses were sound for riding. Nine horses with 1 or both tendons transected were being used for athletic activities. Lacerated tendons were sutured in 16 horses, and 15 of these survived. Tendons were not sutured in 34 horses, and 24 of these survived. We were not able to detect any association between outcome and tendon sheath involvement or between outcome and limb involvement (forelimb vs hind limb).

Free access
in Journal of the American Veterinary Medical Association

Summary

A study of 15 American miniature horses (amh) that underwent surgical treatment for colic was performed. Information obtained from the medical records included signalment, clinical signs, type and location of gastrointestinal lesion, and postoperative complications. All 15 amh had intraluminal obstructions, attributable to feed impactions (11 horses), enteroliths (2), and sand (2). The most common location of obstruction was the small colon, which was involved in 9 of the 15 cases. All 15 amh survived and were discharged from the hospital. Six of the 15 amh underwent subsequent surgical treatment for abdominal disorders. Elapsed time between the first and second operations ranged from 1 month to 5 years. Intestinal adhesions were observed in all amh that were surgically treated twice. Thus, despite the fact that most of the amh had a simple intraluminal obstruction, 40% (n = 6) developed adhesions that required or complicated a second surgery. Of the 15 amh, 87% (n = 13) survived at least 12 months after the initial exploratory celiotomy. These findings suggest that most surgical abdominal conditions in amh can be corrected; however, precautions should be taken to avoid or minimize adhesion formation.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To estimate the prevalence of radiographic abnormalities (lesions) in Thoroughbred racehorses at 2-year-old in-training sales and determine whether these lesions and 1-furlong presale workout times were associated with subsequent racing performance.

Design—Retrospective cohort study.

Animals—953 Thoroughbreds.

Procedures—Repository radiographs of carpal, metacarpophalangeal and metatarsophalangeal (fetlock), stifle, and tarsal (hock) joints were examined. Horses with lesions were classified by lesion type and location. Race performance variables were compared between horses with and without lesions and between horses categorized by 1-furlong presale workout times (< or ≥ 11 seconds).

Results—299 horses had ≥ 1 lesion, and 654 had no lesion detected. Odds of starting a race and of earning money racing were lower for horses with any lesion and lower for horses with proximal phalangeal dorsoproximal articular margin chip fracture, proximal sesamoid bone fracture or sesamoiditis, or wedge-shaped central or third tarsal bones, compared with horses that had no lesion. For horses that raced, proximal phalangeal dorsoproximal articular margin chip fractures were associated with lower lifetime earnings, and flattening of the medial femoral condyle was associated with fewer 3-year-old racing starts, compared with values for horses that had no lesion. Horses with workout times < 11 seconds had greater odds of having lifetime starts, lifetime earnings, and maximum purse above threshold (median) values than did horses with slower workout times.

Conclusions and Clinical Relevance—No radiographic lesions prevented all affected horses from racing. Among horses that raced, few differences were found in performance for horses with and without lesions.

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in Journal of the American Veterinary Medical Association

Summary

Surface oximetry was used to evaluate viability of the ascending colon in 60 horses with naturally occurring colonic volvulus or displacement. Tissue surface oxygen tension (Ps o 2 ) was measured on the serosal surface of the pelvic flexure after anatomic correction of the colonic obstruction. Horses with Ps o 2 > 20 mm of Hg were predicted to have viable colon; whereas, horses with Ps o 2 ≤ 20 mm of Hg were predicted to have nonviable colon. Results of surface oximetry were compared with final outcome. For surface oximetry, sensitivity (ability to accurately identify colon that was nonviable) was 53%, but specificity (ability to accurately identify bowel that was viable) was 100%. Negative predictive value (probability that a horse with Ps o 2 > 20 mm of Hg truly had viable bowel) was 87%, and positive predictive value (probability that a horse with Ps o 2 ≤ 20 mm of Hg truly had nonviable bowel) was 100%. The overall accuracy was 88%. Of the 45 horses that had a colonic Ps o 2 > 20 mm of Hg and survived, 7 had been given, on the basis of subjective assessment of visual criteria, a good prognosis, 28 had been given a guarded prognosis, and 10 had been given a poor prognosis. Of the horses that had a colonic Ps o 2 > 20 mm of Hg but died after surgery because of further colonic infarction, confirmed at necropsy, 4 had been given a poor prognosis, and 3 had been given a guarded prognosis. Of the 8 horses that had a colonic Ps o 2 ≤ 20 mm of Hg and died after surgery, 7 had been given a poor prognosis, and 1 had been given a guarded prognosis. We concluded that surface oximetry, a relatively noninvasive technique, provided a better prediction of survival in horses with colonic volvulus or displacement than did visual inspection alone.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

Fifty Thoroughbred horses were examined. All horses had been in race training for a minimum of 4 months before examination and had worked at racing speed; 24 horses had raced. All horses were clinically sound at the time of examination. Ultrasonography was performed, using a 7.5-MHz transducer with built-in fluid offset. Videotaped images of the palmar soft tissue structures were obtained at 4, 8, 12, 16, 20, and 24 cm distal to the base of the accessory carpal bone (dacb). Images were digitized, and each image was calibrated. Values for cross-sectional area (csa) and mean echogenicity (me) were then determined from the cross-sectional images of the superficial digital flexor (sdf) and the deep digital flexor (ddf) tendons, using an image-analysis program.

The sdf tendons were compared between right and left forelimbs at each level, and from proximad to distad on each limb, as were the ddf tendons. The relation between the sdf and ddf tendons for the same forelimb was determined at each level. There were no significant differences in csa or me at equivalent levels of the left and right sdf tendons. Mean (± sd) csa was 1.01 (± 0.12) cm2 at 4 cm dacb, 0.95 (± 0.14) cm2 at 12 cm dacb, and 1.12 (± 0.15) cm2 at 24 cm dacb. Adjusted me was 2.34 (± 0.34) at 4 cm dacb, 2.03 (± 0.38) at 12 cm dacb, and 2.04 (± 0.35) at 24 cm dacb.

The left and right ddf tendons did not have significant differences in csa or me at any level. Cross-sectional area was 1.13 (± 0.18) cm2 at 4 cm dacb, 1.01 (± 0.12) cm2 at 12 cm dacb, and 1.75 (± 0.29) cm2 at 24 cm dacb. Adjusted me was 2.60 (± 0.46) at 4 cm dacb, 2.49 (± 0.49) at 12 cm dacb, and 2.50 (± 0.44) at 24 cm dacb.

At all levels, the left and right sdf tendons were smaller and less echoic than the ddf tendons of the same limb. The sdf and ddf tendons had an hourglass shape, with smallest csa at 12 cm dacb. Mean echogenicity generally decreased for the sdf and ddf tendons from proximad to distad on the limb.

These results indicate that for clinically normal trained Thoroughbred racehorses, there should be no significant difference in csa or echogenicity between the left and right sdf tendons at equivalent distances dacb. There should be no significant differences in the left and right ddf tendons at equivalent levels dacb. The sdf tendon is usually smaller and less echoic than the corresponding ddf tendon at each level.

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

SUMMARY

Ultrasonographic cross-sectional area (csa) measurements of equine superficial digital flexor (sdf) tendon were obtained to determine the feasibility of ultrasonography for csa measurement of tendon in vivo and in vitro. Ultrasonographic measurements were compared with a more traditional csa measurement method, ink-blot analysis. In addition, values for ultrasonographic sdf tendon mean echogenicity were obtained in vivo and in vitro. The left forelimb sdf tendons of 23 horses were evaluated ultrasonographically. Cross-sectional images were acquired at 4-cm intervals distal to the base of the accessory carpal bone (dacb) to the level of the proximal sesamoid bones while horses were standing squarely. After euthanasia, the left forelimbs were mounted in a materials testing system (mts) and loaded under tension to standing load. Ultrasonographic images were again acquired at the same locations. The ultrasonographic images were digitized, and values for ultrasonographic csa and mean echogenicity were obtained for each level.

Immediately after mechanical testing, a 1-cm-thick transverse section of sdf tendon at 12 cm dacb was removed. Three ink blots were prepared from each end of the removed tendon section and digitized. The 6 csa values were averaged to generate a value for morphologic csa for each sdf tendon at 12 cm dacb.

Standing ultrasonographic tendon csa at 12 cm dacb was consistently smallest (mean ± sd csa = 86 ± 11 mm2), followed by mts ultrasonographic csa (mean, 95 ± 12 mm2), ink-blot morphologic csa being largest (mean, 99 ± 15 mm2). Comparison of standing and mts ultrasonographic csa values at 12 cm dacb revealed a strong positive linear correlation between methods (R 2 = 0.74, P = 0.001). Comparison of ink-blot csa at 12 cm dacb with standing and mts ultrasonographic csa revealed strong positive linear correlations (R 2 = 0.64, P = 0.001 and R 2 = 0.72, P = 0.001, respectively).

For ultrasonographic mean echogenicity, standing values insignificantly exceeded mts values at each level. The authors conclude that ultrasonography is a useful technique for the noninvasive assessment of sdf tendon csa that can be applied in vivo and in vitro.

Free access
in American Journal of Veterinary Research

Summary

The forefimb superficial digital flexor (sdf) tendons of 6 Thoroughbreds were examined clinically and ultrasonographically during the first 4 months of race training. Sonograms were interpreted clinically and by use of computer-aided analysis. Tendon tissue from all horses was examined histologically at the end of the study.

Computer-aided analysis of sonograms of the sdf tendons revealed trends toward an increase in mean cross-sectional area and a decrease in mean echogenicity over time with training. An inverse relation was found between increase in cross-sectional area and decrease in mean echogenicity over time in training. Two of the trained horses developed clinical signs of mid sdf tendonitis. Ultrasonography revealed an increase in cross-sectional area and decrease in mean echogenicity of clinically affected areas of the sdf tendons of 1 horse, compared with changes observed prior to the onset of tendonitis (these changes were not statistically significant). Blood vessels and lymphatics supplying the clinically and ultrasonographically affected tendon sites were large and thick-walled. These changes were not observed in the tendons of the other horses at the end of the study.

The authors conclude that equine sdf tendons adapt to the early months of race training by increasing in size and decreasing in echogencity, as determined by ultrasonography.

Free access
in American Journal of Veterinary Research

SUMMARY

Results of studies in human beings and other species have indicated that aging significantly influences the strength, modulus of elasticity, and energy storage ability of tendon. We wanted to determine the effects of aging on the material and ultrasonographic properties of equine superficial digital flexor (sdf) tendon. Ultrasonographic measurements of left forelimb sdf tendon cross-sectional area and mean echogenicity were made in 23 standing horses ranging in age from 2 to 23 years. All horses had not been in work for a minimum of 6 months prior to the study. After euthanasia, left forelimb bone-muscle-tendon-bone specimens were mounted in a materials testing system. The sdf tendon was cyclically loaded sinusoidally 100 times at 0.5 Hz from 1.5 to 5.0% strain, then was submitted to 10-minute creep-and-stress relaxation tests. Modulus of elasticity, load at 3% strain, and creep-and-stress relaxation were determined for each specimen. A significant positive correlation was found between elastic modulus and age. Correlation was not found between age and sdf tendon cross-sectional area or mean echogenicity. When 2-year-old horses were compared with older horses, the latter had tendons with a significantly (P = 0.007) greater modulus of elasticity. The authors conclude that increasing age through maturity is associated with a corresponding increase in equine sdf tendon elastic modulus.

Free access
in American Journal of Veterinary Research

Summary

To quantify some components of prepurchase evaluations in horses, records from 134 evaluations performed during a 2-year period were reviewed and the outcome was determined via telephone follow-up interview. Sixty-two percent of the prepurchase evaluations had been performed at the clinic and 38% had been performed in the field by the ambulatory service. All evaluations included physical and lameness examinations, whereas radiography (49%), endoscopy (15%), nerve blocking (5%), transrectal palpation (3%), hematologic analysis (2%), electrocardiography (2%), drug testing for analgesic agents (2%), and ultrasonography of the flexor tendons (1%) were not always performed. Fifty-nine percent of horses evaluated at the clinic were radiographed, compared with 33% of horses evaluated in the field (P < 0.05).

Thirty-seven percent of horses evaluated were judged serviceable for their intended use. Thirty-five percent of horses evaluated at the clinic were assessed to be serviceable, compared with 41% of those evaluated in the field (P < 0.05). Horses used for pleasure riding (48%) tended to be considered serviceable more often than horses used for more athletic endeavors (3-day eventing, 33%; hunter/jumper, 24%; show, 31%; dressage, 30%). The most common basis for finding a horse unserviceable was lameness (88%).

On the basis of a telephone interview, horses were divided into 5 groups: horses determined unserviceable on evaluation and not purchased (n = 40); horses determined unserviceable on evaluation, purchased, and then found serviceable on follow-up interview (n = 35); horses determined unserviceable on evaluation, purchased, and then found unserviceable on follow-up interview (n = 9); horses determined serviceable on evaluation, purchased, and found serviceable on follow-up interview (n = 42); and horses determined serviceable on evaluation, purchased, and found unserviceable on follow-up interview (n = 8).

The buyer and seller were present at the evaluation in 34% of cases. The buyer alone was present in 57% of cases, the seller alone in 4% of cases, whereas neither was present in 6% of cases. The potential buyer had used the horse for its intended purpose prior to the prepurchase evaluation in 39% of cases for a mean time of 20.5 days, but this did not appear to affect the serviceability of the horse on follow-up evaluation. Five horses that were leased for > 6 months prior to purchase were all serviceable on follow-up interview, irrespective of the findings at the time of the prepurchase evaluation.

There was a tendency for the value of horses examined at the clinic to be higher than those evaluated by the ambulatory service. The price paid by the buyer was reduced through negotiations on the basis of the prepurchase evaluation in 6% of cases.

Lameness was seen only in horses within the unserviceable group. Lameness tended to be seen more often in horses valued > $2,500 (61%, 46/75) than in horses valued ≤ $2,500 (48%, 28/59). Lameness was associated with 92% (22/24) of horses valued at > $2,500 within the group judged to be unserviceable and not purchased.

Radiography was performed to investigate a specific lameness in 24% (32/134) of evaluations and for survey purposes in 25% (34/134) of evaluations. Of horses radiographed within the unserviceable group, radiography commonly was performed for specific lameness (84%, 32/38) and rarely for survey purposes (24%, 9/38), whereas only survey radiographs were obtained from the serviceable group because no horses exhibited a specific lameness. Radiography was significantly (P < 0.05) more likely to have been performed in horses valued > $2,500 (65%, 49/75) than in those valued < $2,500 (29%, 17/59), and this trend was reflected in all categories. For survey radiographs, the combination of tarsi and bilateral distal forelimbs was the most commonly radiographed area (44%). Bilateral distal forelimbs alone were the second most commonly radiographed area (41%).

A written report summarizing the findings of the evaluation was furnished in 24% of cases. At the time of follow-up interview, 75% of buyers indicated that they would have liked a written report.

Free access
in Journal of the American Veterinary Medical Association