Search

Objective: To evaluate effects of sex, fracture configuration, affected limb, and screw placement on outcome of Thoroughbreds with condylar fractures involving the third metacarpal or metatarsal bone., Design: Cohort study. Animals-56 horses., Procedure: Age, sex, affected limb, fracture configuration, fracture length, fracture fragment width, and distance of the most distal screw from the articular surface were analyzed in logistic regression models., Results: Females were more likely to have displaced fractures and race in fewer races after surgery than males. Sex and fracture configuration were associated with number of postoperative races. Among horses that returned to racing, those with thicker fracture fragments were 11 times as likely as horses with thinner fracture fragments to win a race after surgery. Horses with longer fractures and older horses had fewer postoperative races. Horses in which the most distal screw had been placed further from the joint surface had more races., Conclusions and Clinical Relevance: Results suggest that female horses with displaced condylar fractures and male horses with nondisplaced condylar fractures are more likely to be referred for treatment. The effect of sex on outcome for these horses cannot be clearly separated from the effect of fracture configuration. When adjusted for fracture configuration, males were 6 times as likely as females to race after surgery. When adjusted for sex, horses with nondisplaced fractures were 17 times as likely as horses with displaced fractures to race after surgery. Results suggest that the most distal screw should be placed above the epicondylar fossa.

Objective: To compare racing performance before and after prosthetic laryngoplasty for treatment of laryngeal neuropathy in inexperienced and experienced Thoroughbred racehorses., Design: Retrospective study., Animals: 52 Thoroughbred racehorses treated with prosthetic laryngoplasty for laryngeal neuropathy., Procedure: Lifetime race records were analyzed by use of a verified regression model. Individual race records and hospital records were also reviewed., Results: Experienced horses had a decline in performance, as measured by performance index, earnings percentage, and mean prediction error, during the 6-month period before prosthetic laryngoplasty. Performance improved after surgery, relative to performance in 1 to 4 races immediately before surgery, but did not attain previous baseline values for performance index and earnings percentage, although racing speed was restored to baseline values. Factors associated with failure to attain baseline levels of performance included other racing-related injuries and disorders, major complications of surgery, and age. Individually, however, many horses had long and successful careers after surgery. Performance of inexperienced horses after surgery was at least equal to that of experienced horses., Conclusions and Clinical Relevance: In addition to warning clients of the complications associated with prosthetic laryngoplasty, it may be prudent to provide a guarded prognosis for full restoration of racing performance in older horses, unless they are especially talented and are free of other racing-related problems.

Objective: To determine the relationship between prediction errors of a regression model of racing finish times and earnings or finish position; the relationship between standardized finish times, determined by use of this model, and earnings or finish position; and whether this model was valid when applied to data for horses that underwent surgical treatment., Design: Survey., Sample Population: Records of 6,700 healthy Thoroughbreds racing in Louisiana and of 31 Thoroughbreds with idiopathic left laryngeal hemiplegia that underwent surgical treatment., Procedure: Predicted and standardized finish times were calculated by use of the regression model for healthy horses, and the relationships between prediction error (actual--predicted finish time) and standardized finish times, and earnings and finish position, were examined. Then, the regression model was applied to data for horses with hemiplegia to determine whether the model was valid when used to calculate predicted and standardized finish times for lifetime performance data., Results: Prediction error and standardized finish times were negatively correlated with earnings and positively correlated with finish position and, thus, appeared to be reliable measures of racing performance. The regression model was found to be valid when applied to lifetime performance records of horses with laryngeal hemiplegia., Clinical Implications: Prediction error and standardized finish times are measures of racing performance that can be used to compare performances among Thoroughbred racehorses across a variety of circumstances that would otherwise confound comparison.

Objective: To develop a statistical model to evaluate the influence of specific parameters on racing performance in Thoroughbreds., Design: Survey., Sample Population: Racing records of Thoroughbreds performing in Louisiana from 1981 to 1985., Procedure: Race results for 20 randomly selected days from 5 racetracks during 5 years were analyzed, using regression analysis., Results: The most influential parameter was distance raced. There were significant differences in racing performance among horses at different tracks. At the tracks examined, fast racing surfaces resulted in significantly faster finish times than good racing surfaces, and good racing surfaces resulted in significantly faster finish times than muddy racing surfaces. Finish times also were significantly faster as a function of increasing purse amount and age of horse. Finish times were significantly faster during quarter 4 (summer) and significantly slower during quarter 1 (fall). Races were run at significantly faster times as the number of the race progressed during the day. The finish times were significantly slower as the number of horses competing in the race increased, as the weight carried by the horse increased, and as the starting position away from the rail increased., Clinical Implications: The coefficients used in the statistical model of this report may be used by researchers to compare before injury and after treatment finish times. The coefficients can be used to standardize past racing performances to uniform conditions, thus permitting comparison from 1 race to another to determine success of treatments and to inform owners of prognosis.

Surgery was performed on a 3-year-old 110-kg male ostrich (Struthio camelus) to remove a sequestrum from the dorsal aspect of the left tarsometatarsal bone. A pneumatic tourniquet was positioned proximal to the surgical site and inflated to 600 mm of Hg. Systolic blood pressure increased 35% over 105 minutes while the tourniquet was inflated. Systolic blood pressure decreased 31.5% within 30 seconds after removal of the tourniquet pressure. Recovery from anesthesia and surgery was routine. The tourniquet-induced hypertension in this ostrich was similar to that reported for human beings and horses.

Two horses became acutely lame following a fall during strenuous exercise and were diagnosed as having disruption of the caudal component of the reciprocal apparatus. Clinical signs consisted of lameness of the right pelvic limb, characterized by flexion of the hock and simultaneous extension of the stifle. Radiography revealed an avulsion fracture from the supracondylar tuberosity and fossa of the distal portion of the femur in one horse. Clinical and radiographic findings indicated avulsion of the lateral origin of the gastrocnemius and superficial digital flexor muscles. Treatment consisted of stall rest, limb immobilization, and phenylbutazone administration. One horse recovered to soundness and the other deteriorated and was euthanatized.

Between 1977 and 1984, 31 Thoroughbred horses (mean age, 2.8 years) were surgically treated for slab fractures of the third carpal bone. All fractures involved the articular surfaces of the intercarpal and the carpometacarpal joints in a frontal plane and had a cuboidal or slab shape. In 20 of the horses, the bone was fractured during racing and in 8 of the horses, the bone was fractured during race training. The right limb was affected more frequently than was the left limb (24 vs 7, P less than 0.05). Twenty-one (67.6%) horses raced at least once after recovery from the surgery. Data were available from 11 claiming horses that had raced at least twice before their injuries and 4 times after recovery. A claiming horse is one that competes where any horse entered is subject to being purchased for the designated amount of the claiming race; therefore, each race tends to automatically attract entrants of similar ability. In this group of 11 horses, claiming value decreased from a mean of $13,900 to a mean of $6,500 (P less than 0.05), and the mean finish position was 5.8 +/- 3.16 before injury and 5.8 +/- 3.30 after recovery. The mean claiming value for horses that had not raced before injury, but had raced after recovery (n = 5) was $8,150.

Uterine rupture was diagnosed in 2 postpartum mares with hemorrhagic vaginal discharge. Both mares had abdominal pain, as evidenced by pawing, kicking at the abdomen, or attempting to roll. Peritoneal fluid analysis was useful in establishing a diagnosis. One mare had many RBC in the peritoneal fluid and was anemic; this mare was managed medically with oxytocin, antibiotics, and blood transfusion. The mare was able to raise her foal to weaning age. The second mare had many RBC, degenerate neutrophils, and intracellular and extracellular bacteria in peritoneal fluid. Surgical repair of the uterus was performed, and the mare was treated for peritonitis. The mare later became pregnant.

A retrospective study was made of 21 horses in which proximal interphalangeal arthrodesis had been performed. The right hindlimb was the most often affected (52%). Acute trauma was the most common reason for performing the surgery (62%). Follow-up data were obtained from the owners regarding return to serviceability . When available, follow-up radiographs and clinical examinations were reviewed. Of the 20 horses on which follow-up information was available, 16 were serviceable . Of the horses in which a hindlimb was arthrodesed , 86% were serviceable , whereas 67% of the horses affected in the forelimb were serviceable . An average of 1 year was required for return to serviceability . Follow-up radiography of forelimb cases revealed radiographic changes consistent with navicular disease, distal interphalangeal degenerative joint disease, and a bony exostosis off the dorsal surface of the third phalanx; however, these radiographic changes did not correlate well with the owner's assessment of serviceability . Follow-up clinical examination of forelimb cases revealed 2 horses in which the toe came off the ground during weight bearing.

The technique and results of arthroscopic surgery for the removal of osteochondral fragments from 1,000 carpal joints in 591 horses are reported. Of the 591 horses, 580 were racehorses (including 349 Quarter Horses and 220 Thoroughbreds). The distal aspect of the radial carpal bone was the most commonly affected site, followed by the proximal aspect of the intermediate carpal bone and distolateral aspect of the radius. More than one carpal joint was simultaneously operated on in 58.9% of the Quarter Horses and in 37.4% of the Thoroughbreds. Marked differences in the amount of damage were noted at arthroscopy, compared with what was observed on radiography. Arthroscopic surgery was an effective technique for removing the osteochondral fragments as well as for treating other lesions. The overall functional ability as well as cosmetic appearance of the limbs were excellent. There was no postoperative intra-articular infection. Postsurgical follow-up information was obtained for 445 racehorses. After surgery, 303 (68.1%) raced at a level equal to or better than their preinjury level, 49 (11.0%) had decreased performance or still had problems referable to the carpus, 23 (5.2%) were retired without returning to training, 28 (6.3%) sustained another chip fracture, 32 (7.2%) developed other problems, and 10 (2.2%) sustained collapsing slab fractures while racing. When horses were separated into 4 categories of articular damage, the performance in the 2 most severely affected groups was significantly inferior. One hundred thirty-three of 187 horses with grade-1 damage (71.1%), 108 of 144 with grade-2 damage (75.0%), 41 of 77 with grade-3 damage (53.2%), and 20 of 37 horses with grade-4 damage (54.1%) returned to racing at a level equal to or better than their preinjury level. In examining the prognosis relative to site of the fracture, the prognosis for both breeds was worst with lesions of the third carpal bone.