80 patients undergoing total knee arthroplasty were randomized to periarticular injection of liposomal bupivacaine or plain bupivacaine as a part of a multimodal pain management protocol. An additional 40 patients recruited prior to the initiation of the study were also used as historical controls for analysis. The results of this study indicated that periarticular injections with either formulation of bupivacaine resulted in significantly lower narcotic usage and initial pain scores when compared to historical controls. Comparisons between the two injections indicated that the use of liposomal bupivacaine resulted in significantly less pain at the time of physical therapy on postoperative day 1 and 2; however, there were no differences in mean pain scores on any postoperative day between liposomal and conventional bupivacaine. Additionally, time to first narcotic use was significantly longer in the plain bupivacaine group and total narcotic usage was significantly smaller.