554 patients scheduled for either primary or revision hip or knee arthroplasty were randomized to one of two skin preparation groups: pre-admission chlorhexidine protocol the night before and morning of surgery, or to standard in-hospital preparation with an iodine povacrylex and isopropyl alcohol solution. The purpose of this study was to evaluate and compare the incidence of periprosthetic joint infection and deep incisional infection between the two groups. Results after follow-up of 1 year demonstrated a significantly lower rate of infection in those who had received the pre-admission chlorhexidine protocol.