A novel compound, liposomal bupivacaine (EXPAREL®, Pacira Pharmaceuticals, Inc., Parsippany, NJ, USA), has been proposed for use in total knee arthroplasty. To our knowledge, only one randomized controlled trial involving use of this compound in total knee arthroplasty has been published and was performed as a phase two dose ranging trial comparing liposomal bupivacaine to bupivacaine HCl. No statistically significant difference between the two compounds was shown, but a trend towards benefit in short term pain control was shown with EXPAREL 532mg.