Preoperative use of amoxicillin and gentamicin in elective orthopaedic surgery in horses – a randomised controlled study
Präoperative Applikation von Amoxicillin und Gentamicin – Eine randomisierte, kontrollierte Studie
Stöckle S D, Failing K, Koene M, Fey K
This randomised controlled trial evaluates the necessity of preoperative antimicrobial prophylaxis in equine clean, elective orthopaedic surgery. 75 horses undergoing clean orthopaedic surgery were randomly assigned to either a treated or a control group. Treated horses received 10 mg/kg amoxicillin and 6.6 mg/kg gentamicin once 30 to 45 minutes prior to first incision. The horses remained in the clinic for at least six days. During the first three days after surgery, rectal body temperatures were measured twice and on day four and five once daily. Surgical incisions received score points for exudation, swelling, skin temperature, and dehiscence. A two-factorial ANOVA was used to test for statistically significant differences between groups and over time. For pairwise comparisons between groups or time points, Fisher’s exact test and the (exact) Wilcoxon-Mann-Whitney-test were used. 59/75 horses (78.7 %) were included in statistical analysis. Significantly higher scores for swelling (p = 0.002), and skin temperature (p = 0.007) were observed in treated patients (n = 28), which caused the total score to be significantly higher in treated horses, too (p = 0.002). In both groups, body temperatures were significantly higher in the evening of the day of surgery (p < 0.0001). On the third day after surgery, temperatures in the morning were significantly higher than in the evening (p = 0.007). All other statistical comparisons revealed no significant differences. After the seven-day observation period, one control horse (day 8 postoperatively) and one horse (day 9 postoperatively) in the treated group, that was excluded from statistical analysis due to additional gentamicin administration directly after the operation, developed septic arthritis in the operated joint. Preoperatively administered amoxicillin in combination with gentamicin failed to reduce reactions at incision sites after elective surgical orthopaedic procedures. The routine administration of preoperative antimicrobial prophylaxis in clean, elective orthopaedic surgery in horses lacks scientific data to prove a beneficial effect. Antibiotic administration before or after these procedures should be based on an individual risk-benefit assessment.