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- Author or Editor: George S. Martin x
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Abstract
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.
Conclusion 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. (J Am Vet Med Assoc 2000;217:1870–1877)
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 Populatian—
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. (J Am Vet Med Assoc 1997;210:1641–1645)
Abstract
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. (J Am Vet Med Assoc 2000;217:1689–1696)
SUMMARY
A study was done to determine whether intra-articular pressure is increased in equine metacarpophalangeal joints with increasing degrees of synovial distention, and to correlate elastance of the soft tissue forming the dorsal pouch of the metacarpophalangeal joint to maximal range of motion in flexion. Sixty-seven metacarpophalangeal joints in 36 horses were categorized by palpation and visual inspection of the palmar pouch into 1 of 4 increasing grades of distention. Intra-articular pressures were then measured, using 2 pressure transducers attached to 22-gauge needles, from the dorsal and palmar pouches simultaneously while horses stood squarely under mild sedation. Intra-articular pressure ranged from −13 to +78 mm of Hg. Mean (± sem) palmar pouch pressure was subatmospheric (−2.53 ± 2.78 mm of Hg) in joints in which the palmar pouch was not discernible (grade 0), and was markedly increased (+37.13 ± 2.775 mm of Hg) in joints in which the palmar pouch was distended laterally beyond the lateral branch of the suspensory ligament (grade 3). Grade of distention was positively correlated with intra-articular pressure (r = 0.758; P < 0.001). Significant compartmentation (P < 0.002) was observed between the dorsal and palmar pouches in all horses. In 25 of the aforementioned horses (42 joints), which were active or retired Thoroughbred racehorses with variable degree of metacarpophalangeal joint injury/disease, a third needle was inserted into the dorsal pouch, and 0.5-ml increments of saline solution were added every 10 seconds to perform a pressure/volume (elastance) study of the dorsal pouch. The elastance study for each joint ended when leakage into the palmar pouch was detected by the pressure transducer placed in that region. A flexed lateral radiographic view was taken of each metacarpophalangeal joint in maximal flexion. The maximal angle of flexion was measured from the radiograph, and this angle was subtracted from 180° to acquire the range of motion in flexion. Range of motion in flexion has strong negative correlation (r = −0.68; P < 0.0001) with elastance (stiffness) of the dorsal pouch, and moderate negative correlation with the initial baseline pressure in the palmar (r = −0.47; P < 0.0015) and dorsal pouches (r = −0.48; P < 0.0001). To adjust for the possible correlations resulting from repeated measures on limbs within horses, a normal linear mixed model was used to assess the effect of limb (right vs left), range of motion in flexion, and volume of saline solution added on the dependent variable (Δ mm of Hg) in the elastance study. There was no significant limb effect, but a highly significant effect regarding volume of saline solution added (P < 0.00001) and range of motion in flexion (P < 0.00001). Loss of range of motion in flexion of this joint is associated with shortening or loss of the initial low elastance (flat) phase of the elastance profile. Measuring the elastance of the dorsal pouch or measuring maximal range of motion in flexion provides an objective measure of the degree of metacarpophalangeal joint stiffness secondary to joint disease.
