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Summary

Over a 10-year period, cecocolic intussusception was diagnosed in 11 of 842 horses undergoing surgical treatment for colic at the New York State College of Veterinary Medicine. Eight horses died or were euthanatized because of poor prognosis determined at surgery or because of postoperative complications. Three horses recovered without complication after manual reduction of the intussusception and partial typhlectomy, using an intestinal stapling device.

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

Abstract

Objective

The objective of the study reported here was to evaluate the effects of changing velocity on stance time and ground reaction force (GRF) measurements in horses at the walk and trot.

Design

Force plate gait analysis was used to evaluate clinically normal horses at variable velocities. Ground reaction force measurements and stance times were recorded and compared.

Animals

12 adult horses.

Procedure

Data were obtained from 192 valid trials at the walk and 162 valid trials at the trot. Vertical, braking, and propulsive peak forces and impulses were measured. Pearson’s correlation coefficients were determined for velocity and stance time and all measured forces and impulses in the forelimbs and hind limbs. Trials were divided into distinct velocity ranges. Trials obtained at velocities within the established ranges were analyzed to evaluate changes in vertical, braking, and propulsive peak forces and impulses at differing speeds within the walk and trot gaits.

Results

At the walk and trot, a significant negative correlation was found between velocity and forelimb and hind limb stance times. Velocity and stance time were significantly correlated with many of the GRF and impulse measurements. Velocity was significantly correlated with vertical and braking forces in the hind limbs at the walk, with vertical force in the forelimbs at the trot, and with braking force in the forelimbs and hind limbs at the trot. Velocity and stance time correlated significantly with forelimb and hind limb vertical impulses. Forelimb and hind limb stance times decreased significantly as velocity increased. Hind limb braking force increased and forelimb and hind limb vertical impulses decreased significantly as walk velocity increased. Forelimb braking force increased significantly between velocity ranges at the trot.

Conclusions

Results of this study confirm that a significant negative linear correlation exists between subject velocity and stance times in clinically normal horses at the walk and trot. Significant correlations were also identified between velocity and many GRF measurements, indicating that subject velocity does influence the generation of GRF measurements in horses. Variation in subject velocity should be minimized when performing force-plate analysis in horses. (Am J Vet Res 1996;57:7-11)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the amount of time required for surface temperatures of thoracic and pelvic limbs in horses to return to pre-exercise temperatures after high-speed treadmill exercise, as detected via infrared thermographic imaging.

Design—Prospective study.

Animals—6 Thoroughbreds.

Procedures—All horses had been trained on and conditioned to use of a high-speed treadmill. Baseline thermographic images were obtained 3 days prior to exercise (baseline). Horses were exercised on a treadmill at a walk for 5 minutes, a slow trot (3 m/s) for 5 minutes, a trot (5 to 6 m/s) for 5 minutes, and a slow gallop (6 to 8 m/s) for 5 minutes, then back to a trot for 3 minutes, a slow trot for 3 minutes, and a walk for 3 minutes prior to stopping. Thermal images were obtained immediately after stopping exercise (0 minutes) and 5, 15, 45, and 60 minutes and 6 hours after stopping exercise. Ambient temperature surrounding each horse was recorded.

Results—In all regions, significant differences in surface temperatures were detected between thermograms obtained before exercise and those obtained immediately after, 5 minutes after, and 15 minutes after exercise was stopped. There were no significant differences in surface temperatures between thermograms obtained before exercise and those obtained ≥ 45 minutes after exercise was stopped.

Conclusions and Clinical Relevance—In horses, images generated via infrared thermography are not influenced by exercise-generated heat ≥ 45 minutes after exercise is stopped.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical findings in and outcome of horses with fractures of the second or fourth metacarpal or metatarsal bone that underwent segmental ostectomy, leaving the proximal and distal portions of the bone undisturbed.

Design—Retrospective case series.

Animals—17 horses.

Procedures—Medical records were reviewed, and information on signalment, affected bone, lesion type, surgical procedure, amount of bone removed, and surgical and postsurgical complications was obtained. Follow-up information was obtained through telephone conversations with owners, trainers, and referring veterinarians.

Results—One horse had a fracture involving the distal third of the second metacarpal bone; 13 had fractures involving the middle third of the second metacarpal bone (n = 4), fourth metacarpal bone (5), or fourth metatarsal bone (4); and 3 had fractures involving the proximal third of the second (2) or fourth (1) metacarpal bone. Affected portions of the bones were surgically resected, leaving the proximal and distal portions undisturbed. All horses returned to previous performance levels without evidence of lameness. Cosmetic results were good to excellent.

Conclusions and Clinical Relevance—Results suggest that horses with a complicated injury of the proximal, middle, or distal portion of the second or fourth metacarpal or metatarsal bone may be successfully treated by means of segmental ostectomy of the abnormal portion of the bone. (J Am Vet Med Assoc 2004;224:271–274)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate clinical effects of immobilization followed by remobilization and exercise on the metacarpophalangeal joint (MPJ) in horses.

Animals—5 healthy horses.

Procedure—After lameness, radiographic, and force plate examinations to determine musculoskeletal health, 1 forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by cast removal and increasing amounts of exercise, beginning with hand-walking and ending with treadmill exercise. Lameness examination, arthrocentesis of both MPJ, single-emulsion radiographic examination, nuclear scintigraphic examination, ground-reaction force-plate analysis, and computed tomographic examination were done at various times during the study.

Results—All horses were lame in the immobilized MPJ after cast removal; lameness improved slightly with exercise. Force plate analysis revealed a significant difference in peak forces between immobilized and contralateral limbs 2 weeks after cast removal. Range of motion of the immobilized MPJ was significantly decreased, and joint circumference was significantly increased, compared with baseline values, during the exercise period. Osteopenia was subjectively detected in the immobilized limbs. Significant increase in the uptake of radionucleotide within bones of the immobilized MPJ after cast removal and at the end of the study were detected. Loss of mineral opacity, increased vascular channels in the subchondral bone, and thickening within the soft tissues of the immobilized MPJ were detected.

Conclusions and Clinical Relevance—Results indicate that 8 weeks of enforced exercise after 7 weeks of joint immobilization did not restore joint function or values for various joint measurements determined prior to immobilization. (Am J Vet Res 2002;63:282–288)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the pharmacokinetic-pharmacodynamic parameters of enrofloxacin and a low dose of amikacin administered via regional IV limb perfusion (RILP) in standing horses.

Animals—14 adult horses.

Procedures—Standing horses (7 horses/group) received either enrofloxacin (1.5 mg/kg) or amikacin (250 mg) via RILP (involving tourniquet application) in 1 forelimb. Samples of interstitial fluid (collected via implanted capillary ultrafiltration devices) from the bone marrow (BMIF) of the third metacarpal bone and overlying subcutaneous tissues (STIF), blood, and synovial fluid of the radiocarpal joint were collected prior to (time 0) and at intervals after tourniquet release for determination of drug concentrations. For pharmacokinetic-pharmacodynamic analyses, minimum inhibitory concentrations (MICs) of 16 μg/mL (amikacin) and 0.5 μg/mL (enrofloxacin) were applied.

Results—After RILP with enrofloxacin, 3 horses developed vasculitis. The highest synovial fluid concentrations of enrofloxacin and amikacin were detected at time 0; median values (range) were 13.22 μg/mL (0.254 to 167.9 μg/mL) and 26.2 μg/mL (5.78 to 50.0 μg/mL), respectively. Enrofloxacin concentrations exceeded MIC for approximately 24 hours in STIF and synovial fluid and for 36 hours in BMIF. After perfusion of amikacin, concentrations greater than the MIC were not detected in any samples. Effective therapeutic concentrations of enrofloxacin were attained in all samples.

Conclusions and Clinical Relevance—In horses with orthopedic infections, RILP of enrofloxacin (1.5 mg/kg) should be considered as a treatment option. However, care must be taken during administration. A dose of amikacin > 250 mg is recommended to attain effective tissue concentrations via RILP in standing horses.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine history, physical and diagnostic examination findings, medical treatment, and outcome of horses with open injuries to the digital flexor tendon sheath treated with the assistance of tenoscopy.

Design—Retrospective study.

Animals—20 horses.

Procedure—Medical records of 20 horses with open injuries to the digital flexor tendon sheath were reviewed. Signalment, history, physical and diagnostic examination results, bacteriologic culture and susceptibility testing results, surgical and medical treatments, and follow-up examination results were determined. Outcome was determined by use of telephone interview or physical examination.

Results—All horses were treated with tenoscopicassisted lavage and débridement. Eighteen horses survived, and 2 were euthanatized during treatment. All horses were either grade-4 or grade-5 lame before treatment. Ten horses returned to previous use. Four horses were considered mildly lame and in athletic use. Three horses were considered mechanically lame and are in use with reduced expectations. One horse was lost to follow-up after being sold. One horse was euthanatized for financial reasons and 1 because of complications from regional sepsis.

Conclusions and Clinical Relevance—Tenoscopy appears to be a useful modality in the treatment of open injury to the digital flexor tendon sheath in horses. Direct viewing, guided débridement, and targeted large-volume lavage are advantages obtained with intrathecal arthroscopy. Tenoscopy, when combined with antimicrobial and anti-inflammatory treatment, appears to offer a good chance of survival for affected horses. (J Am Vet Med Assoc 2002;220:1823–1827)

Full access
in Journal of the American Veterinary Medical Association

Summary

Biaxial palmar digital neurectomy of all limbs was performed on 6 mixed-breed castrated adult male horses, using a standard guillotine method. Using a Teflon catheter, 20 mg (2 ml) of sodium hyaluronate (group 1), 2 ml of phosphate-buffered saline solution (group 2), or catheter placement with no infusion (group 3) was applied to 4 (group 1) or 2 (groups 2 and 3) of 8 incisions/horse. Treatments were administered after closure of the neurectomy incision, and the catheter was removed. Horses were evaluated daily for 1 week, then weekly over a 9- week period for evidence of lameness, swelling, and ultrasonographic changes. On week 9, horses were euthanatized and neurectomy sites were removed en bloc for histologic evaluation of axonal regrowth, inflammation, and fibrosis. Neither lameness nor sign of painful neuroma was observed clinically in any of the horses. Neurectomy eliminated cutaneous heel sensation in all limbs for the duration of the study. Swelling was evident at all neurectomy sites. There were no significant differences between treatment sites for measurement of pastern circumference or ultrasonographic evaluation of incisional swelling. Foci of ultrasonographic hyperechogenicity increased over time, but there was no significant difference in hyperechogenicity between treatment groups. Histologic evidence of neuroma formation was observed at all sites. Morphometric assessment of neuroma cross-sectional areas revealed no significant difference between the groups, as did subjective histologic assessment of neuroma density and fibrous tissue content. We conclude that there are no clinical, ultrasonographic, or histologic effects on neuroma formation and fibrosis at sites of palmar digital neurectomy associated with a single perineural administration of sodium hyaluronate or phosphate-buffered saline solution.

Free access
in American Journal of Veterinary Research