Prognosis for survival to discharge and racing performance in Thoroughbred foals treated for single joint septic arthritis (2009-2016).

BACKGROUND

Haematogenous septic arthritis is a major cause of morbidity and mortality in foals. Previous research has demonstrated a variable prognosis for athletic performance in foals diagnosed with septic arthritis.

OBJECTIVE

To determine the racing prognosis for Thoroughbred foals, 6 months of age or less with single septic joint of presumed haematogenous origin without recognised systemic sepsis or other serious comorbidity compared with a group of maternal sibling controls.

STUDY DESIGN

Retrospective cohort study.

METHODS

Data were collected from Rood and Riddle Equine Hospital in-patient records from 2009 to 2016. Parameters evaluated included: diagnostic tests, therapeutic regimens, final diagnosis and outcome. Racing records were obtained from a public archive for cases and two maternal siblings. Univariable analyses of categorical variables were conducted.

RESULTS

Ninety-five cases of Thoroughbred foals 6 months of age or less were included in this study. The last measured synovial cell count prior to hospital discharge or euthanasia (OR 0.5, p value 0.002, 95% CI: 0.3-0.8) was an indicator of poor prognosis for survival to discharge. Overall, the prognosis for survival was high (93%). Total winnings per career were the only statistically significant racing performance variable between cases and paired controls (IRR 0.7, p value, 0.05, 95% CI: 0.5-0.99).

MAIN LIMITATIONS

Retrospective study, evaluation of one regional population, potential for unknown prior exclusionary treatment on farm, unknown chronicity, no data on acute phase proteins and proportion of neutrophils of synovial fluid and unknown medical records of controls.

CONCLUSIONS

While total winnings were reduced compared with maternal siblings, Thoroughbred foals with single joint septic arthritis have a favourable prognosis for both survival and starting in a race.