Objective—To determine whether iatrogenic
hemarthrosis of the metacarpophalangeal joint could
be used as a model for temporary reversible joint pain
Animals—8 adult horses.
Procedure—Each horse was evaluated on a treadmill
before and after injection of 1 metacarpophalangeal
joint with 10 mL of autogenous blood. Horses were
evaluated subjectively and objectively by use of a
computerized force measurement system at intervals
until lameness abated. The mean force difference
between injected and noninjected limbs at all time
periods after injection was compared with the difference
between limbs at baseline. From each horse,
synovial fluid samples collected before and 24 hours
and 30 days after injection were analyzed for total protein
concentration and cell type and number. Venous
blood samples were collected before and 6 and 24
hours after injection for assessment of plasma cortisol
Results—For 24 hours after injection, the mean force
difference between injected and noninjected limbs
was significantly increased over baseline. The greatest
force difference was detected after 2 and 4 hours.
Baseline and 24-hour force data were not significantly
different. Compared with baseline values, synovial
fluid protein concentration and nucleated cell and
RBC counts were increased significantly at 24 hours
after injection but were not different at 30 days after
injection. No significant changes in plasma cortisol
concentration were detected at any time point.
Conclusions and Clinical Relevance—In horses,
iatrogenic hemarthrosis of the metacarpophalangeal
joint appears to induce temporary reversible lameness
with a mild to moderate degree of synovitis.
(Am J Vet Res 2005;66:1084–1089)
Objective—To develop an objective, accurate method
for quantifying forelimb ground reaction forces in
horses by adapting a human in-shoe pressure measurement
system and determine the reliability of the
system for shod and unshod horses.
Animals—6 adult Thoroughbreds.
Procedure—Horses were instrumented with a
human in-shoe pressure measurement system and
evaluated at a trot (3 m/s) on a motorized treadmill.
Maximum force, stance time, and peak contact area
were evaluated for shod and unshod horses. Three
trials were performed for shod and unshod horses,
and differences in the measured values were examined
with a mixed model ANOVA for repeated measures.
Sensor accuracy was evaluated by correlating
measured variables to clinically observed lameness
and by a variance component analysis.
Results—4 of 6 horses were determined to be lame
in a forelimb on the basis of clinical examination and
measured values from the system. No significant differences
were observed between shod and unshod
horses for maximum force and stance time. A significant
decrease in peak contact area was observed for
shod and unshod horses at each successive trial.
Maximum force measurements provided the highest
correlation for detecting lameness ( r = 0.91, shod
horses; r = 1.0, unshod horses). A variance component
analysis revealed that 3 trials provided a variance
of 35.35 kg for maximum force (± 5.78% accuracy),
0.007 seconds for stance time (± 2.5% accuracy), and
8.58 cm2 for peak contact area (± 11.95% accuracy).
Conclusions and Clinical Relevance—The in-shoe
pressure measurement system provides an accurate,
objective, and effective method to evaluate lameness
in horses. ( Am J Vet Res 2001;62:23–28)
Objective—To describe pathological findings identified with MRI in the distal tarsal bones of horses with unilateral hind limb lameness attributable to tarsal pain and to compare the usefulness of MRI with that of radiography and nuclear scintigraphy in evaluation of this region.
Design—Retrospective case series.
Animals—20 lame horses.
Procedures—In all horses, MRI, radiography (4 standard projections), and nuclear scintigraphy of the tarsus had been performed. Horses were excluded if the results of all 3 imaging modalities were not available or if lameness was detected in more than 1 limb. Pathological changes identified with MRI were cross-referenced with the findings determined with other imaging modalities.
Results—Compared with MRI findings, the following lesions were identified with radiography: medullary and subchondral bone sclerosis in 9 of 16 horses, pathological changes related to osseous hyperintensity in 0 of 10 horses, and osteoarthritis in 5 of 8 horses. Standard radiographic projections did not aid in the identification of fracture of the distal tarsal bones (3 horses). Location of increased radiopharmaceutical uptake with nuclear scintigraphy corresponded with the location of pathological changes detected with MRI in all horses. The intensity of the radiopharmaceutical uptake on nuclear scintigraphic images did not correspond with the severity of the pathological changes identified with MRI.
Conclusions and Clinical Relevance—Radiography was unreliable for the detection of pathological changes related to osseous hyperintensity identified with MRI, fracture, and subchondral bone sclerosis in the equine tarsus. Nuclear scintigraphy was effective in localizing pathological changes, but MRI provided superior anatomic detail.
Case Description—3 horses with penetrating wounds to the shoulder area were examined because of forelimb lameness.
Clinical Findings—All horses had physical examination findings (decreased cranial phase of the stride, swelling in the shoulder region, and signs of pain on manipulation of the shoulder) that were suggestive of problems in the upper portion of the forelimb. Injury to the biceps tendon or bursa was the primary differential diagnosis in each instance, but no abnormalities involving those structures were found. Radiographic and ultrasonographic imaging revealed injuries to the caudal eminence of the greater tubercle of the humerus, the infraspinatus tendon, and the infraspinatus bursa. Examination with ultrasound was more sensitive than radiography at detecting both osseous and soft tissue changes.
Treatment and Outcome—All 3 horses responded favorably to treatment with antimicrobials and non-steroidal anti-inflammatory drugs. Although initial response to standing lavage was favorable in 1 horse, endoscopic lavage was later required. Standing removal of fracture fragments was performed in 2 horses. Ultrasonographic imaging was helpful in monitoring the response to treatment and changes in the affected structures. All 3 horses eventually became sound after treatment.
Clinical Relevance—Infraspinatus bursitis and tendonitis should be included in the differential diagnoses of horses with shoulder lameness. Diagnosis and monitoring should include ultrasonographic monitoring. The prognosis for return to soundness after appropriate treatment appears to be good.