Does Preadmission Cutaneous Chlorhexidine Preparation Reduce Surgical Site Infections After Total Knee Arthroplasty?

BACKGROUND: Many preventive methodologies seek to reduce the risk of surgical site infections after total knee arthroplasty (TKA), including the use of preoperative chlorhexidine baths and cloths. Although we have demonstrated in previous studies that this may be an efficacious method for infection prevention, our study was underpowered and we therefore set out to evaluate this with a larger sample size. QUESTIONS/PURPOSES: (1) Does a preadmission chlorhexidine cloth skin preparation protocol decrease the risk of surgical site infection in patients undergoing TKA? (2) When stratified using the National Healthcare Safety Network (NHSN) risk categories, which categories are associated with risk reduction from the preadmission chlorhexidine preparation protocol?
METHODS: In our study, all patients (3717 total) who had undergone primary or revision TKA at a single institution between January 1, 2007, and December 31, 2013, were identified, of whom 991 patients used the chlorhexidine cloths before surgery and 2726 patients did not. All patients were provided cloths with instructions before surgery; however, as a result of a lack of compliance, we were able to substratify patients into treatment and control cohorts. Additionally, we substratified patients by NHSN risk category to determine differences in infection between the two cohorts (cloth versus no cloth). Patient medical records and an infection-tracking database were reviewed to determine the development of periprosthetic infection (patients who had superficial infections were excluded from our study) in both groups after 1 year surveillance. We then calculated relative risk reductions with use of chlorhexidine gluconate and stratified results based on NHSN risk category.
RESULTS: Use of a preoperative chlorhexidine cloth skin preparation protocol is associated with reduced relative risk of periprosthetic infection after TKA (infections with protocol: three of 991 [0.3%]; infections in control: 52 of 2726 [1.9%]; relative risk [RR]: 6.3 [95% confidence interval [CI], 1.9-20.1]; p = 0.002). When stratified by NHSN risk category, periprosthetic infection risk reduction was seen in the medium-risk category (protocol: one of 402 [0.3%]; control: 25 of 1218 [2.0%]; RR, 8.3 [CI, 1.1-60.7]; p = 0.038), but no significant difference was detected in the low- and medium-risk groups (RR, 2.1 [CI, 0.5-9.6; p = 0.33] and RR, 11.3 [CI, 0.7-186.7; p = 0.09]).
CONCLUSIONS: A prehospital chlorhexidine gluconate wipe protocol appears to reduce the risk of periprosthetic infections after TKA, primarily in those patients with medium and high risk. Although future multicenter randomized trials will need to confirm these preliminary findings, the intervention is inexpensive and is unlikely to be risky and therefore might be considered on the basis of this retrospective, comparative study. LEVEL OF EVIDENCE: Level III, therapeutic study.