The purposes of this study are to document the antiemetic efficacy of multimodal antiemetic protocol in patient after Total Knee Arthroplasty using regional anesthesia, midazolam & propofol, hydration & oxygen supplement, preemptive & multimodal contemporary pain management and to determine whether Ramosetron prophylaxis would provide additional antiemetic effect on this protocol. We hypothesized that the incidence of Postoperative nausea and vomiting during multimodal antiemetic protocol would be lower than Apfel's expected postoperative nausea and vomiting incidence. It was also hypothesized that Ramosetron prophylaxis would provide additional antiemetic effect.