Forelimb skeletal scintigraphy responses in previously untrained Thoroughbreds undergoing initial treadmill training.

Scintigraphy has been used in numerous clinical settings to examine horses to determine the origin of lameness problems, but it has not been used previously to monitor prospectively the skeletal responses of a group of similarly-trained racehorses. Our hypothesis was that in naïve Thoroughbred (TB) racehorses, initial treadmill training induces increased radiopharmaceutical uptake in high-motion joints and in the dorsal third metacarpal bone (MC3). Eight previously-untrained TB racehorses underwent sequential skeletal scintigraphic examinations as they exercised daily for 9 weeks on an inclined treadmill. At the end of Weeks 0 (pre-training), 3 (trotting at 4.2 m/s and initial galloping), 6 (galloping at 7.5 m/s), and 9 (sprinting 600 m at 12.5 m/s), horses received 140 mCi 99m Technetium-methylene diphosphonate i.v. followed by a standard skeletal scintigraphic forelimb examination 2 h later. Views were graded for increased radiopharmaceutical uptake by 3 co-investigators who were blinded to horse identification, breed, sex, date, and clinical findings. Results were compared before and after training for each skeletal location using the Mann-Whitney Rank Sum Test with the level of significance set at P<0.05. Initial treadmill training resulted in increased radiopharmaceutical uptake in the carpus (P = 0.031), metacarpophalangeal joint (P = 0.021), proximal phalanx (P = 0.035), and distal phalanx (P = 0.003). Training did not affect dorsal MC3 radiopharmaceutical uptake (P>0.05).

The effect of a combination of medetomidine-butorphanol and medetomidine, butorphanol, atropine on glomerular filtration rate in dogs.

The effects of intramuscularly administered medetomidine and butorphanol (MB), and medetomidine, butorphanol, atropine (MBA) on glomerular filtration rate (GFR) were determined in six dogs as measured by 99m-Tc-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) nuclear scintigraphy. Direct systolic, diastolic, and mean arterial blood pressures and heart rate were measured at regular time intervals before, during, and after GFR calculations. The mean GFR measurement following MB was significantly greater (4.44 ml/min/kg) than following MBA (3.82 ml/min/kg) or saline treatment (3.41 ml/min/kg). There was no significant difference between the mean GFR measurements following MBA injection and following saline injection. Diastolic and mean arterial pressures following MBA injection were significantly higher than the values recorded after either MB or saline alone. Heart rate following MB administration was significantly lower than that recorded for dogs receiving MBA or saline alone. The results of this study indicate that the administration of medetomidine in combination with butorphanol significantly increases total GFR in healthy dogs, while the administration of the combination of medetomidine, butorphanol, and atropine does not.

Rehabilitation of dogs with surgically treated cranial cruciate ligament-deficient stifles by use of electrical stimulation of muscles.

OBJECTIVE: To determine effect of electrical muscle stimulation (EMS) on rate and degree of return to function of the limb and development of degenerative joint disease (DJD) after surgical creation and subsequent stabilization of the cranial cruciate ligament (CrCL)-deficient stifle. ANIMALS: 12 clinically normal adult large (19.5 to 31.5 kg) dogs. PROCEDURE: Dogs were anesthetized, and the right CrCL was severed via arthrotomy, destabilizing the stifle. After 3 weeks, the stifle was surgically stabilized. Three weeks later, 6 dogs were subjected to an EMS treatment protocol for the thigh muscles. At 5, 9, 13, and 19 weeks after stifle destabilization, treated (n = 6) and control (n = 6) dogs were evaluated for return of stifle function. Gross and histologic evaluations of the stifles were performed at 19 weeks after stifle destabilization. RESULTS: Treated dogs had significantly (P = 0.001) better lameness score than did control dogs. There was less palpable crepitation of the stifle in treated dogs (P = 0.06); treated dogs also had significantly (P = 0.01) fewer radiographic signs of bone changes. Thigh circumference was significantly (P = 0.02) larger in treated dogs. There was less gross cartilage damage (P = 0.07) in the EMS-treated dogs, but more medial meniscal damage (P = 0.058, cranial pole; P = 0.051, caudal pole). CONCLUSIONS: Improved lameness scores, larger thigh circumference, and decreased radiographically apparent bony changes observed for the treated group of dogs support the hypothesis that dogs treated by EMS after surgical stabilization of the CrCL-deficient stifle had improved limb function, with less DJD, than did dogs treated with the currently accepted clinical protocol of cage rest and slow return to normal activity. However, results of force plate evaluation did not support the hypothesis. Increased meniscal damage in dogs treated by EMS may be cause for concern.

Treatment of rupture of suspensory ligament and superficial flexor tendon in a bull.

Rupture of the suspensory ligament at the insertions on the proximal sesamoid bones, and of the superficial flexor tendon of the left fore limb, occurred in an adult Angus bull as a result of fighting. There was severe hyperextension of the metacarpophalangeal (MCP) joint with the dewclaws almost touching the ground. Radiographs revealed severe hyperextension of the MCP joint with the sesamoid bones aligned directly distal to the metacarpus. Initially, a full length fiberglass cast was applied with the limb partially flexed within the cast and the heels elevated. The cast was replaced twice. The cast was removed after 136 days and the bull was bearing full weight on the limb. Prolonged immobilisation of the limb produced new bone in the area (a normal response in cattle) to cause ankylosis of the traumatized MCP joint and partial ankylosis of the carpus. The bull was being used for pasture breeding one year after the injury.

Artifacts and technical errors presented as part of the 1996 ACVR oral certification examination.

Cases used for the examination consisted of various imaging artifacts and technical errors. The candidate was expected to name or identify the problem and discuss its cause and prevention. For the purpose of completeness, the scope and detail given here is in excess of that needed to pass the examination. Unless the problem was obvious, the examiner pointed out the problem to be discussed.

The macroscopic vascular anatomy of the equine ethmoidal area.

The vascular anatomy of the ethmoidal area in six normal horses and two normal ponies was studied using vascular-corrosion casts. The major arterial supply to the ethmoidal area stems from an intracranial source. The internal and external ethmoidal arteries anastomose on the rostral intracranial surface of the cribriform plate to form the arterial ethmoidal rete which arborizes and passes through the perforations of the cribriform plate to supply the ethmoid labyrinth. A minor arterial supply to the ventral portion of the ethmoid labyrinth stems from a small caudal nasal branch of the sphenopalatine artery. Multiple parallel venules drain the ethmoid labyrinth rostrally to its apex then join the venous drainage from the surrounding sinuses.

Surgical repair of peripheral detachment of the medial meniscus in 34 cattle.

A detachment of the periphery of the medial meniscus from the joint capsule and medial collateral ligament in 34 cattle was repaired by securing the meniscus to the joint capsule with vertical mattress sutures during arthrotomy. Of 28 cattle with follow-up reports, 20 had recovered satisfactorily by their owners' evaluations; 17 were either not lame or slightly lame after the operation and three were moderately lame. Three of four cattle without follow-up reports were either not lame or slightly lame when discharged from the hospital.

Quantitative noninvasive assessment of liver size in clinically normal dogs.

Measurements of liver size were made from radiographs of 16 clinically normal anesthetized dogs. Two measurements were made from each of 3 views: right and left lateral and ventrodorsal. Each measurement was correlated with liver weight and volume. Liver weight and volume were also correlated with both measurements from the same radiograph multiplied together. All measurements, with the exception of ventrodorsal depth, correlated significantly (P less than 0.05) with liver weight and volume. The multiplication of the 2 measurements made from the right lateral radiograph correlated most highly with liver weight. These data were then compared with those from similar studies involving liver measurements obtained from nuclear scintigraphic and ultrasonographic scans on the same dogs. The radiographic measurements made from the right lateral view had the highest correlation with liver weight, followed by the nuclear scintigraphic measurements made from the same position.

Variable locations of nutrient foramina of the proximal phalanx in forelimbs of Thoroughbreds.

Bilateral metacarpophalangeal radiographs of 100 Thoroughbreds were examined for visualization and location of the major nutrient foramen of the proximal phalanx. The foramina were located on the dorsal or palmar aspects of the cortex or were not visible radiographically. Of the 100 horses, 60 had the same pattern in both forefeet. In the remaining 40 horses, the left and right proximal phalangeal foramina were asymmetric. Of the 200 proximal phalangeal foramina (100 horses), 53 were on the dorsal aspect of the cortex and 101 were on the palmar aspect of the cortex; 46 were not visible radiographically. Significant effect of age or gender could not be determined.

Peripheral detachment of the medial meniscus with injury to the medial collateral ligament in 50 cattle.

In 50 cattle the periphery of the medial meniscus had separated from the joint capsule and medial collateral ligament. The meniscus was hypermobile when varus and valgus stress were applied to the stifle joint, and concurrent injury to the collateral ligament allowed the medial side of the stifle joint to gape. Separation of the medial collateral ligament from the joint capsule and medial meniscus was seen at arthrotomy in 34 animals. In addition to signs of stifle injury, the affected cattle tended to abduct the leg and bear weight on the medial claw.

Fractured capital femoral epiphysis in twin ewes.

Capital femoral physeal fractures occurred simultaneously in twin 2-year-old Shropshire ewes. The fractures resulted in gradual, progressive lameness and recumbency. There was no history of trauma and no other ewes in the flock were affected. The fractures occurred at an age when the capital physis should have been closed. Clinical and postmortem examination of the ewes and evaluation of the ration did not reveal predisposing factors for the condition. A familial tendency for fractured capital femoral epiphysis is well documented in human beings, but there is no known familial tendency in sheep.

Radial and tibial fracture repair with external skeletal fixation. Effects of fracture type, reduction, and complications on healing.

Twenty-eight consecutive fractures of the canine radius and tibia were treated with external skeletal fixation as the primary method of stabilization. The time of fixation removal (T1) and the time to unsupported weight-bearing (T2) were correlated with: (1) bone involved; (2) communication of the fracture with the external environment; (3) severity of the fracture; (4) proximity of the fracture to the nutrient artery; (5) method of reduction; (6) diaphyseal displacement after reduction; and (7) gap between cortical fragments after reduction. The Kruskal-Wallis one-way analysis of variance was used to test the correlation with p less than .05 set as the criterion for significance. The median T1 was 10 weeks and the median T2 was 11 weeks. None of the variables correlated significantly with either of the healing times; however, there was a strong trend toward longer healing times associated with open fractures and shorter healing times associated with closed reduction. Periosteal and endosteal callus uniting the fragments were observed radiographically in comminuted fractures, with primary bone union observed in six fractures in which anatomic reduction was achieved. Complications observed in the treatment of these fractures included: bone lysis around pins (27 fractures), pin track drainage (27 fractures), pin track hemorrhage (1 fracture), periosteal reaction around pins (27 fractures), radiographic signs consistent with osteomyelitis (12 fractures), degenerative joint disease (2 dogs), and nonunion (1 fracture). Valgus or rotational malalignment resulted in 16 malunions of fractures. One external fixation device was replaced and four loose pins were removed before the fractures healed. One dog was treated with antibiotics during the postoperative period because clinical signs of osteomyelitis appeared.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuclear scintigraphic assessment of liver size in clinically normal dogs.

Measurement of liver size was made on nuclear scintigraphic images obtained from 16 clinically normal, anesthetized dogs in ventral, dorsal, right and left lateral, and left dorsal oblique positions after administration of technetium 99m-sulfur colloid. Linear measurements of liver length and width were made from each scintiscan, and liver surface area was determined by setting a region of interest manually and by use of a computer count of pixels above a minimal intensity (threshold method). All linear measurements had a statistically significant (P less than 0.05) correlation with liver and body weight, with the exception of the measurements of liver width made on dogs in dorsal and left lateral dorsal oblique positions. The highest correlation (r = 0.89) between the scintigraphic measurements and liver weight was the multiplication of measurements of liver width and length from the right lateral view. Although all area determinations were significantly (P less than 0.05) correlated with liver and body weight, for most views, the manual method of determining the region of interest had a slightly better correlation with the liver weight than did the threshold method.

Two-dimensional echocardiography for diagnosis of dirofilariasis in nine dogs.

Two-dimensional echocardiography (real-time ultrasonography) of the heart was used to detect adult Dirofilaria immitis in the right ventricle and atrium of a 2-year-old Labrador Retriever with occult heartworm disease and in 8 microfilaremic dogs. Adult worms were easily identified as parallel echogenic lines separated by a hypoechoic region. Images of worms fixed in formalin after recovery from dogs with experimentally induced heartworm infection had an identical appearance. The sensitivity of this imaging procedure was tested on the 8 dogs with naturally acquired infection, and worms were observed in the right ventricle of 7 of the dogs. Two-dimensional echocardiography appears to be a sensitive noninvasive procedure, which can be used in combination with thoracic radiography and serotests to improve accuracy of diagnosis of canine occult heartworm disease.

Clinical, radiographic, and scintigraphic findings associated with enthesitis of the lateral collateral ligaments of the tarsocrural joint in standardbred racehorses.

Injury of the lateral collateral ligaments of the tarsocrural joints was diagnosed in nine Standardbred pacers. The average age was 4.9 years. The severity of the lameness varied from severe to subtle and joint effusion was seen in eight of 10 tarsocrural joints. A positive hindlimb flexion test was seen in four of six cases in which results were recorded. The identification of the site of involvement was based on a focal intense 'hot spot' seen on scintigraphy, and new bone formation seen radiographically at the anatomical sites of insertion of the long lateral collateral ligament of the tarsocrural joint in nine limbs and the short lateral collateral ligament of one limb. The authors believe this injury to be enthesitis caused by the cyclic trauma of training and racing speed. The primary therapy was rest. Of six cases which returned to training, three raced as well or better than before injury.

Variable locations of nutrient foramina of the proximal phalanx in forelimbs of standardbreds.

Bilateral metacarpophalangeal radiographs of 100 Standardbreds were examined for visualization and location of nutrient foramina of the proximal phalanx. Foramina were located in the dorsal or palmar cortex or were not visible radiographically. Of 100 horses, 45 had bilaterally symmetrical foramina. Left and right proximal phalangeal foramina were asymmetrical in the remaining 55 horses. Of 200 proximal phalangeal foramina (in 100 horses), 78 were in the dorsal cortex, 61 were in the palmar cortex, and 61 were not visible radiographically. A significant (P = 0.05) effect of age or sex could not be determined.

Misdiagnosis in normal radiographic anatomy: eight structural configurations simulating disease entities in dogs and cats.

Radiographic diagnosis is a combination of accurately identifying normal and abnormal variants, projecting anatomic structures, and describing abnormal findings. Disease conditions may easily be confused with normal structures. Eight conditions and normal counterparts that are presented illustrate the similarities and differences between normal and abnormal.

Evaluation of experimental transection and partial excision of the caudal cruciate ligament in dogs.

The caudal cruciate ligament (CaCL) of one stifle joint in seven dogs was transected and a 2 to 4 mm section was removed. Six months after surgery, none of the dogs were lame. Thigh muscle circumference, stifle range of motion, and internal tibial rotation in the operated limb were not significantly different from the preoperative measurements or the contralateral, unoperated limb. A caudal drawer motion was consistently present in the stifle joints with a transected CaCL. A radiographic evaluation of the operated stifle joints did not reveal osteoarthritic changes; four of seven stifle joints had an irregular fat pad 6 months after surgery. Results of a joint fluid analysis revealed a slight increase in synovial cells within treated stifle joints; inflammatory cells were not observed. The only gross morphologic change in stifle joints with a severed ligament was enlarged knobby remnants of the CaCL. Articular cartilage defects or osteophytes were not observed. Results of a histologic examination of the CaCL remnants revealed synovial cellular capping and intraligamentous fibroplasia. Based on a limited number of dogs, it was concluded that isolated transection of the CaCL produced minimal clinical and pathologic changes in the stifle joint during a 6 month period.