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Abstract

Objective—To determine clinical characteristics of and outcome in Thoroughbred racehorses with tibial or humeral stress fractures.

Design—Retrospective study.

Animals—99 Thoroughbreds with tibial or humeral stress fractures.

Procedure—Information obtained from the medical records included history, signalment, and clinical, radiographic, and scintigraphic findings. Outcome was determined by interviewing trainers, performing follow- up examinations, and analyzing race records.

Results—Seventy-four tibial stress fractures were identified in 61 Thoroughbreds, and 48 humeral stress fractures were identified in 39 Thoroughbreds (1 horse was included in both groups). Tibial stress fractures occurred most commonly in 2-year-old or unraced horses. Fractures were located in 1 of 3 sites in the tibia (most commonly, the caudolateral cortex of the mid-diaphysis) and 1 of 4 sites in the humerus (most commonly, the caudodistal cortex). Forty-four of 58 (76%) tibial stress fractures and 18 of 32 (56%) humeral stress fractures were identified radiographically. Humeral stress fractures involving the caudodistal cortex were not detected radiographically. Treatment consisted of rest and exercise restriction, and 49 of 61 (80%) horses with tibial stress fractures and 30 of 39 (77%) horses with humeral stress fractures returned to racing. Humeral stress fractures recurred in 6 horses.

Conclusions and Clinical Relevance—Results suggested that in Thoroughbred racehorses, tibial stress fractures occurred most commonly in unraced 2 year olds, whereas humeral fractures occurred most commonly in older horses that had raced previously. The prognosis for racing following treatment was good. (J Am Vet Med Assoc 2003;222:491–498)

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical and radiographic features of subchondral cystic lesions (SCL) of the proximal extremity of the tibia in horses that could be used to classify these lesions as being related to osteochondrosis or osteoarthritis and to evaluate results of surgical debridement.

Design—Retrospective study.

Animals—12 horses with 14 SCL.

Procedure—Medical records and radiographs obtained before and after treatment were reviewed.

Results—In 6 young horses (8 lesions), SCL were considered to be related to osteochondrosis; all involved the lateral tibial condyle. The remaining 6 horses were mature and had radiographic evidence of osteoarthritis in addition to SCL. Arthroscopic debridement was performed in 4 horses in which lesions were considered to be a result of osteochondrosis and in 3 horses with osteoarthritis. Three horses in which SCL were considered to be a result of osteochondrosis performed athletically after debridement. Two horses with moderate osteoarthritis returned to work after arthroscopic debridement but at a lower level of athletic performance. One horse with SCL related to osteochondrosis responded to medical treatment and went on to race.

Conclusions and Clinical Relevance—Results suggest that arthroscopic debridement of SCL is feasible in horses in which lesions involve the cranial portion of the lateral or medial tibial condyle, and that treated horses may be able to perform athletically. (J Am Vet Med Assoc 2001;218:408–413)

Full access
in Journal of the American Veterinary Medical Association

Summary

Flow-volume loops generated from 6 Standardbreds at rest and during treadmill exercise were evaluated for their use in detecting upper airway obstruction. Tidal breathing flow-volume loops (tbfvl) were obtained from horses at rest and exercising at speeds corresponding to 75% of maximal heart rate and at maximal heart rate. The tbfvl were evaluated, using a pulmonary function computer; calculated indices describing airflow rate and expiratory-to-inspiratory airflow ratio for individual loops were determined. In addition to tbfvl indices, standard variables of upper airway function also were measured: peak airflow, peak pressure, and calculated inspiratory and expiratory impedances. Measurements were recorded before left recurrent laryngeal neurectomy (lrln; baseline) and 14 days after surgically induced left laryngeal hemiplegia.

When horses were at rest, tbfvl shape and indices describing the loop were highly variable. In contrast, in exercising horses, tbfvl shape was consistent and coefficients of variation of loop indices were less during exercise than at rest. After lrln, tbfvl from exercising horses indicated marked inspiratory airflow limitation, while the expiratory airflow curve was preserved. Peak inspiratory flow rate and inspiratory flow at 50 and 25% of tidal volume decreased, and the ratio of peak expiratory to inspiratory airflow and that of midtidal volume expiratory and inspiratory airflow rates increased significantly (P < 0.05). Inspiratory impedance also increased after lrln.

Although in resting horses tbfvl were not a useful indicator of upper airway obstruction, examination of tbfvl from exercising horses allowed objective, specific, and repeatable detection of upper airway obstruction. The technique was noninvasive, rapid, and well tolerated by horses; thus, it is a potentially valuable clinical diagnostic test.

Free access
in American Journal of Veterinary Research

Summary

Medical records of 51 horses with epiglottic entrapment were reviewed, and the outcome after surgical treatment was evaluated by use of results from a survey of owners and from race records. Horses with epiglottic entrapment and no additional problem (uncomplicated) of the nares, nasal passages, pharynx, or larynx (upper airway) that were treated by transoral axial division (group 1) or resection via laryngotomy (group 2), and horses with epiglottic entrapment complicated by an additional upper airway abnormality (group 3) were compared. The cost of treatment, duration of hospitalization, time to first race start after surgery, and complication rate were significantly (P < 0.05) less in horses in group 1, compared with those in horses of group 2. Owner survey indicated that a significantly greater percentage (82%) of horses in group 1 had a successful outcome after transoral axial division, compared with that (27%) of horses in group 2. Analysis of race records indicated that performance was similar between horses in groups 1 and 2, and significantly more horses with an additional upper airway lesion (group 3) failed to return to racing than did horses with uncomplicated epiglottic entrapment (groups 1 and 2). Transoral axial division of the aryepiglottic fold is recommended as an appropriate treatment for uncomplicated epiglottic entrapment. Resection via laryngotomy should be reserved for treatment of epiglottic entrapment associated with excessively thick and scarred aryepiglottic folds and for intermittent epiglottic entrapment in horses for which surgical correction is deemed appropriate. Horses with epiglottic entrapment complicated by previous aryepiglottic fold surgery or another upper airway abnormality, particularly epiglottic deformity or dorsal displacement of the soft palate, should receive a less favorable prognosis for return to athletic performance.

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To compare the apparent viscosity of normal synovial fluid of the mid-carpal, tibiotarsal, and interphalangeal joints of horses.

Design

Viscosity evaluation over a range of shear rates was used to characterize the apparent viscosity of synovial fluids from the 3 joints.

Animals

60 clinically normal adult horses.

Procedure

Viscosity data for synovial fluid samples were obtained over a shear rate range of 10 to 250/s and apparent viscosity was calculated at 50, 100, 150, 200, and 250/s. Effect of shear rate on apparent viscosity was determined, using a two-way ANOVA, with significant differences tested, using a Tukey's test at a significance level of P < 0.05.

Results

Synovial fluid from all these joints indicated shear thinning behavior: decreased apparent viscosity with increased shear rate. Apparent viscosity of synovial fluid from the 3 joints was not significantly different over the shear rate range of 50 to 250/s.

Conclusion

Results of this study indicate that the apparent viscosity of the distal interphalangeal joint is not less than that of other joints, as has been reported.

Clinical Relevance

The observation of decreased synovial fluid viscosity of distal interphalangeal joint fluid should be considered as suggestive of joint disease. (Am J Vet Res 1996;57:879–883)

Free access
in American Journal of Veterinary Research