Effect of displaced versus non-displaced pelvic fractures on long-term racing performance in 31 Thoroughbred racehorses.

OBJECTIVE: To evaluate the long-term racing prognosis for Thoroughbred racehorses with displaced versus non-displaced fractures of the pelvis identified by scintigraphy. DESIGN: Retrospective case analysis. METHODS: Medical records of 31 Thoroughbred racehorses presenting to the University of Melbourne Equine Centre with fractures of the pelvis that were identified by scintigraphy were reviewed. Pelvic fracture site was determined and defined as displaced or non-displaced based on ultrasound and/or radiographic findings. Race records were analysed for each horse, with a minimum of 24 months' follow-up, and correlated with fracture type to determine long-term prognosis for racing. Results are expressed as median and range. RESULTS: Fractures at a single site were more common (n = 22) than fractures involving two sites (n = 9) and the ilial wing was the most commonly affected (n = 12). Thoroughbred racehorses with displaced pelvic fractures at any site (n = 12) raced fewer times within 24 months of diagnosis than horses with non-displaced fractures (n = 19) (median 0.5, range 0-13 vs 7, 0-24; P = 0.037), but there was no clear statistical difference in race earnings between the two groups (median A$0, range A$0-$123,250 vs A$14,440, A$0-$325,500, respectively; P = 0.080). Four horses with displaced fractures (33%) were euthanased on humane grounds because of persistent severe pain. When these horses were excluded from the analysis, there were no differences in performance variables between horses with a displaced or non-displaced pelvic fracture. CONCLUSION: Thoroughbred racehorses with a displaced or non-displaced pelvic fracture that survive the initial post-injury period have a good prognosis for racing.

Murray Valley encephalomyelitis in a horse.

A 5-year-old Thoroughbred mare presented with signs of severe pain and was taken to exploratory laparotomy based on suspicion of an acute abdominal lesion. A mild gastrointestinal lesion was discovered, but was considered disproportional to the severity of signs displayed. The mare was later euthanased because of intractable pain. Comprehensive postmortem examination, including polymerase chain reaction testing of central nervous system tissue samples, allowed a definitive diagnosis of Murray Valley encephalomyelitis to be made. This case demonstrates the variability of clinical presentations in horses infected with Murray Valley encephalitis virus.

Retrospective investigation of prognostic indicators for adult horses with infection of a synovial structure.

OBJECTIVE: To investigate predictors of survival and athletic function in adult horses with infection of a synovial structure. HYPOTHESES: Increasing duration from contamination to referral, bone or tendon involvement and positive microbial culture decreases short-term survival. Synovitis and/or sepsis at 5 days post-admission and involvement of Staphylococcus spp. decreases long-term athletic function. DESIGN: Retrospective study. METHODS: Records over 4 years of adult horses with synovial sepsis were reviewed. A two-tailed Fisher's exact test, Mann-Whitney U test or t-test was used to examine whether variables were predictive of short-term survival and long-term athletic function. RESULTS: During the study period 75 horses underwent treatment for infection of 93 synovial structures. Short-term survival was 84% (63/75) and 54% (30/56) of horses returned to athletic function. Of the variables measured at admission, duration from contamination to referral did not affect survival, whereas evidence of bone or tendon involvement decreased survival and athletic function. Of the variables available during treatment, abnormal synovial fluid at 4-6 days post-admission and positive microbial culture reduced athletic function. Staphylococcal infection was associated with persistent sepsis. CONCLUSIONS: Of the variables available at presentation, only evidence of bone or tendon involvement negatively affected survival and athletic function. During treatment of synovial sepsis, analysis of synovial fluid at 4-6 days and bacterial culture results have prognostic value.