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.
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.
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.
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
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)
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.
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
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)