Protocol changes to reduce implant-associated infection rate after tibial plateau leveling osteotomy: 703 dogs, 811 TPLO (2006-2014).

OBJECTIVE: To determine the influence of a stricter aseptic protocol on implant-associated infection (IAI) rates after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: Seven hundred three dogs (811 TPLO). METHODS: Medical records (2006-2014) of dogs with TPLO with a ≥18-month follow-up were reviewed. An established TPLO protocol was altered to include an iodophore-impregnated adhesive drape, cefazolin administration every 90 minutes intraoperatively and then every 4 hours until hospital discharge, orthopedic surgical gloves, triclosan-coated intradermal sutures (instead of staples), soft-padded bandage with mupirocin ointment, use of single-use gloves while handling treated dogs, and placement of an Elizabethan collar. Signalment, affected limb, protocol changes, IAI, time to explant, and culture and susceptibility results were recorded. Data were analyzed by using Fisher's exact test, Wilcoxon rank-sum test, and a multivariable logistic regression model. RESULTS: TPLO plates were removed from 31 dogs (8.5% prechange, 1.3% postchange) because of a suspected IAI. Bacterial culture results from an explanted screw were positive in 26 dogs (7.4% prechange, 0.94% postchange). The odds ratio (OR) of IAI in the postchange cohort was decreased by 88% (OR 0.12, 95% CI 0.05-0.33) compared with the prechange cohort, after controlling for variables. Staphylococcus spp. were isolated from all implants removed from IAI-positive postchange dogs, 4/5 of which were methicillin resistant. No methicillin-resistant isolates were grown from the prechange cohort implants. CONCLUSION: The protocol tested here decreased IAI rates after TPLO, but most infections diagnosed after its implementation involved methicillin-resistant isolates. CLINICAL SIGNIFICANCE: The protocol reported here may be used as a guide in clinics seeking to reduce their IAI rates after TPLO. Postoperative infections after implementation of this protocol should be monitored to evaluate its potential impact on the emergence of antibiotic resistance.

Implant removal rate from infection after tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To determine implant removal rate associated with infection after tibial plateau leveling osteotomy (TPLO) in dogs and to report antimicrobial susceptibility patterns for isolates. STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 255; 282 TPLO). METHODS: Medical records (April 2006-April 2008) for dogs that had TPLO with ≥ 18 month follow-up were reviewed. Dogs that had implant removal with confirmed bacterial isolation from the implant were studied. Cefazolin (22 mg/kg intravenously) was administered before anesthesia induction for TPLO, every 2 hours intraoperatively, and every 6 or 8 hours until the next morning. Antimicrobial susceptibility testing was performed on isolates. RESULTS: Twenty-one (7.4%) of 282 TPLO required implant removal because of infection. Bacterial species isolated were Actinomyces spp. (1), Corynebacterium spp. (1), Enterococcus spp. (3), hemolytic Staphylococcus coagulase negative (2), nonhemolytic Staphylococcus coagulase negative (3), Staphylococcus spp. coagulase positive (7), methicillin-oxacillin-resistant Staphylococcus coagulase positive (2), and Serratia marcesens (2). Of the antibiotics that had ≥10 isolates tested against them, gentamicin had the highest susceptibility rate (94%), followed by tribrissen (71%), and amoxicillin/clavulanic acid (67%). CONCLUSION: Staphylococcus spp. was reported in 14 of the 21 infections cultured in this study. Based on antimicrobial susceptibility testing, amoxicillin/clavulanic acid would be the best empirical treatment.