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 describe the use of CT in the diagnosis of and presurgical planning for equids with keratomas treated by hoof wall resection and determine postoperative complications and outcome.
DESIGN Retrospective case series.
ANIMALS 29 horses and 3 mules with keratomas treated by partial or complete hoof wall resection following CT imaging of the distal portion of the affected extremity from 2005 through 2016.
PROCEDURES For each equid, physical examination and lameness evaluation were performed, followed by imaging of the distal portion of the affected extremity. A tentative diagnosis of keratoma was made given results of clinical, radiographic, and CT examination, with the definitive diagnosis made on histologic examination. After CT imaging, each equid was treated with hoof wall resection.
RESULTS CT allowed accurate identification of the size and location of 35 keratomas in 33 feet. Thirty equids underwent partial and 2 underwent complete hoof wall resection for keratoma removal. Complications developed in 4 of 31 (13%) equids and included excessive granulation tissue formation at the surgical site (n = 1), excessive granulation tissue formation and worsening lameness (1), incomplete keratoma removal with suspected regrowth (1), and incomplete healing of the surgical site with distal interphalangeal joint sepsis secondary to repeated debridement of abnormal tissue (1). Twenty-eight of 31 (90%) equids returned to their previous activity level.
CONCLUSIONS AND CLINICAL RELEVANCE Preoperative CT examination of the feet was useful in the diagnosis of and surgical planning for keratomas in equids. A low complication rate was achieved with the described techniques.
Objective—To compare variables for screw insertion, pushout strength, and failure modes for a headless tapered compression screw inserted in standard and oversize holes in a simulated lateral condylar fracture model.
Sample Population—6 pairs of third metacarpal bones from horse cadavers.
Procedure—Simulated lateral condylar fractures were created, reduced, and stabilized with a headless tapered compression screw by use of a standard or oversize hole. Torque, work, and time for drilling, tapping, and screw insertion were measured during site preparation and screw implantation. Axial load and displacement were measured during screw pushout. Effects of drill hole size on variables for screw insertion and screw pushout were assessed by use of Wilcoxon tests.
Results—Drill time was 59% greater for oversize holes than for standard holes. Variables for tapping (mean maximum torque, total work, positive work, and time) were 42%, 70%, 73%, and 58% less, respectively, for oversize holes, compared with standard holes. Variables for screw pushout testing (mean yield load, failure load, failure displacement, and failure energy) were 40%, 40%, 47%, and 71% less, respectively, for oversize holes, compared with standard holes. Screws could not be completely inserted in 1 standard and 2 oversize holes.
Conclusions and Clinical Relevance—Enlarging the diameter of the drill hole facilitated tapping but decreased overall holding strength of screws. Therefore, holes with a standard diameter are recommended for implantation of variable pitch screws whenever possible. During implantation, care should be taken to ensure that screw threads follow tapped bone threads.
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)
To determine the median time to maximum concentration (tmax) of amikacin in the synovial fluid of the tarsocrural joint following IV regional limb perfusion (IVRLP) of the drug in a saphenous vein of horses.
7 healthy adult horses.
With each horse sedated and restrained in a standing position, a 10-cm-wide Esmarch tourniquet was applied to a randomly selected hind limb 10 cm proximal to the point of the tarsus. Amikacin sulfate (2 g diluted with saline [0.9% NaCl] solution to a volume of 60 mL) was instilled in the saphenous vein over 3 minutes with a peristaltic pump. Tarsocrural synovial fluid samples were collected at 5, 10, 15, 20, 25, and 30 minutes after completion of IVRLP. The tourniquet was removed after collection of the last sample. Amikacin concentration was quantified by a fluorescence polarization immunoassay. Median maximum amikacin concentration and tmax were determined.
1 horse was excluded from analysis because an insufficient volume of synovial fluid for evaluation was obtained at multiple times. The median maximum synovial fluid amikacin concentration was 450.5 μg/mL (range, 304.7 to 930.7 μg/mL), and median tmax was 25 minutes (range, 20 to 30 minutes). All horses had synovial fluid amikacin concentrations ≥ 160 μg/mL (therapeutic concentration for common equine pathogens) at 20 minutes after IVRLP.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that, in healthy horses, maintaining the tourniquet for 20 minutes after IVRLP of amikacin in a saphenous vein was sufficient to achieve therapeutic concentrations of amikacin in the tarsocrural joint.
OBJECTIVE To evaluate the use of a laparoscopic specimen retrieval pouch for removal of intact or fragmented cystic calculi from standing horses.
DESIGN Retrospective case series.
ANIMALS 8 horses (5 geldings and 3 mares) with cystic calculi.
PROCEDURES Physical examination and cystoscopic, ultrasonographic, and hematologic evaluations of urinary tract function were performed for each horse. A diagnosis of cystic calculus was made on the basis of results of cystoscopy and ultrasonography. Concurrent urolithiasis or other urinary tract abnormalities identified during preoperative evaluation were recorded. Horses were sedated and placed in standing stocks, and the perineum was aseptically prepared. Direct access to the urinary bladder was gained in geldings via perineal urethrotomy or in mares by a transurethral approach. Calculi were visualized endoscopically, manipulated into the retrieval pouch, and removed intact or fragmented (for larger calculi).
RESULTS For 4 geldings and 1 mare, fragmentation was necessary to facilitate calculus removal. Mean duration of surgery was 125 minutes, and trauma to the urinary bladder and urethra was limited to areas of hyperemia and submucosal petechiation. No postoperative complications were encountered for any horse. When lithotripsy was required, the retrieval pouch provided an effective means of stabilizing calculi and containing the fragments for removal.
CONCLUSIONS AND CLINICAL RELEVANCE Use of the laparoscopic specimen retrieval pouch was an effective, minimally traumatic method for retrieving cystic calculi from standing horses. The pouch protected the urinary bladder and urethra from trauma during calculus removal and allowed for stabilization, containment, and fragmentation of calculi when necessary.
Objective—To provide a detailed description of the
vascular anatomy of the distal portion of the forelimbs
of horses by use of computed tomography angiography
Sample Population—6 forelimbs of 5 horses and 1
forelimb from an equine cadaver; none of the horses
had orthopedic or vascular disease.
Procedure—Horses were anesthetized and CTA was
conducted on the dependent forelimb. A catheter
was inserted in the median artery, and contrast medium
was infused at a rate of 3 mL/s. A computed
tomography (CT) scanner was used to obtain contiguous
slices from the region of the proximal sesamoid
bones to the toe. All horses were allowed to recover
from anesthesia. To help identify vessel patterns in
the distal portion of the forelimb, the median artery
and lateral palmar digital vein of a heparinized forelimb
obtained from an equine cadaver were infused
with red and blue polymethylmethacrylate and the
distal portion of that forelimb was then sectioned to
correspond to CTA images.
Results—Vessel patterns in CTA images matched
vascular anatomic structures of the cadaver forelimb
and were consistent with published anatomic structures.
Major and minor vessels were consistently visible
in CTA images of all horses. There were no complications
reported in any horses.
Conclusions and Clinical Relevance—Use of CTA
provided a highly detailed depiction of the vasculature
of the distal portion of the equine forelimb. This was
a safe technique and should be useful in the evaluation
of the blood supply to the distal portion of the
forelimb. (Am J Vet Res 2004;65:1409–1420)
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.
Mesenchymal stromal (stem) cells (MSCs) have been studied to treat many common orthopedic injuries in horses. However, there is limited information available on when and how to use this treatment effectively. The aim of this retrospective study is to report case features, treatment protocols, and clinical outcomes in horses treated with MSCs.
65 horses presenting with tendinous, ligamentous, and articular injuries, and treated with MSCs prepared by a single laboratory between 2016 and 2019. Outcome information was available for 26 horses.
Signalment, clinical signs, diagnostic methods, treatment protocol features (prior and concurrent therapies, cell origin, dose, application site and number), and effective outcomes were analyzed. The analysis was focused on comparing the effect of different MSC treatment protocols (eg, autologous vs allogeneic) on outcome rather than the effectiveness of MSC treatment.
MSC treatment resulted in 59.1% (clinical lameness) to 76.9% (imaging structure) improvement in horses with diverse ages, breeds, sex, and lesions. The use of other therapeutic methods before MSC application (eg, anti-inflammatories, shockwave, laser, icing, resting, bandage and stack wrap, intra-articular injections, and/or surgical debridement) was shown to be statistically more effective compared to MSCs used as the primary therapeutic procedure (P < .05). Autologous versus allogeneic treatment outcomes were not significantly different.
A prospective MSC treatment study with standardization and controls to evaluate the different features of MSC treatment protocols is needed. The various case presentations and treatment protocols evaluated can be used to inform practitioners who are currently using MSCs in clinical practice.
Objective—To determine whether CT provides unique information about the treatment or prognosis for horses with ethmoid hematoma (EH).
Design—Retrospective case series.
Animals—16 horses with EH.
Procedures—Horses with a diagnosis of EH that had undergone a diagnostic CT study were included. Clinical features, treatment, outcome, radiographic and CT images, and histologic specimens were reviewed.
Results—CT provided new diagnostic information that affected treatment in 10 of 16 horses. Bilateral disease occurred in 8 of 16 horses and was undetected in 5 horses prior to CT. Paranasal sinus involvement occurred in all horses, but was incompletely defined prior to CT in 7 of 16 horses. The sphenopalatine sinus was affected in 6 of 16 horses as detected on CT; 4 of 6 of these were bilaterally affected. Medical and surgical treatments were performed. Six of 10 horses had a successful outcome, with recurrence in 4 of 10. Five of 6 patients in which treatment addressed all lesion sites identified by CT had a successful outcome. Bilateral disease did not confer a poor prognosis when all affected sites were treated. Sphenopalatine sinus involvement may have been associated with recurrence.
Conclusions and Clinical Relevance—CT provided anatomic information that may facilitate effective treatment of horses with EH, particularly in patients with bilateral disease and paranasal sinus involvement. Computed tomography is recommended for patients in which the lesion cannot be viewed endoscopically, when sinus involvement or multifocal disease are suspected, or when the lesion has been unresponsive to treatment.