We conducted a randomized controlled trial (RCT) to investigate if iodine impregnated incision drapes (IIID) increases bacterial recolonization rates compared to no drape use under conditions of simulated total knee arthroplasty (TKA) surgery. Background: To prevent surgical site infection (SSI), one of the important issues is managing the patient´s own skin flora. Many prophylactic initiatives have been suggested, including the use of IIID. IIID has been debated for many years and was deemed ineffective in preventing SSI in a recent systematic review [1], while some evidence suggests a potential increase in postoperative infection risk, as a result of IIID use [2]. IIID is sparsely investigated in orthopaedic surgery. An increase in the number of viable bacteria in the surgical field of an arthroplasty operation has a potential to increase the risk of SSI in an otherwise elective and clean procedure [3]. 20 patients scheduled for TKA were recruited. Each patient had one knee randomized for draping with IIID [4] while the contralateral knee was left bare, thus the patients acted as their own controls. Operating theater settings with laminar airflow and standard perioperative procedures were simulated. Sampling was performed with the cup-scrup technique [5] using appropriate neutralizers. Samples were collected from the skin of each knee prior to disinfection and on 2 occasions after skin-preparation, 75 minutes apart. Bacterial quantities were estimated by spread plating with 48-hour aerobic incubation. Outcome was measured as colony forming units per square centimeter of skin. We used Wilcoxon signed-rank test for comparative analysis within and between knees. Following skin-disinfection we found no significant difference in bacterial quantities between the intervention and the control knee (p = 0.388). Neither did we see any difference in bacterial quantities between the two groups after 75 minutes of simulated surgery (p = 0.367). When analyzed within the intervention and control group, bacterial quantities had not significantly increased at the end of surgery when compared to baseline, thus no recolonization was detected (p = 0.665 and 0.609, respectively). Iodine impregnated incision drapes did not increase bacterial recolonization rates in simulated TKA surgery. Thus, the results of this RCT study does not support the hypothesis that iodine impregnated incision drapes promotes bacterial recolonization and postoperative infection risk.
