Tan TL, et al. - To ascertain the efficiency of sub-anesthetic dosing of ketamine during total knee arthroplasty (TKA) on postoperative pain and narcotic consumption, researchers assessed 91 cases in this prospective, randomized, double-blinded clinical trial. Subjects were randomly given intraoperative ketamine infusion at a rate of 6mcg/kg/min for 75 minutes or a saline placebo. No difference was recorded in average pain between ketamine vs placebo at all time points except for at postoperative days 1 (45 vs 56) and 4 (39 vs 49). Only at postoperative day 4, subjects were given ketamine for least pain experienced stated a decrease in pain. They overall did not find a clinically significant improvement in pain and narcotic consumption with intraoperative ketamine administration following TKA.