Three-in-one nerve block with different concentrations of bupivacaine in total knee arthroplasty: randomized, placebo-controlled, double-blind trial

105 patients scheduled to undergo unilateral total knee arthroplasty were randomized to receive either a low dose or a high dose of bupivacaine or a placebo. Results from early post-operative follow-up indicated that patients who received placebo were three times as likely to experience pain. However, this difference between the three groups disappeared at 1 day post-operative follow-up. Additionally, no significant differences between the two groups were found in regards to post-operative nausea or sedation.