Liposomal bupivacaine is applied in a periarticular injection at the conclusion of TKAs to aid in post-operative pain control. Due to the lipid encapsulation of the bupivacaine, only 3% free bupivacaine is released into the tissue at initial infiltration, with the remainder released slowly over approximately a 72 hour time frame. To cover, this gap period, the liposomal bupivacaine is mixed with standard bupivacaine to allow for an immediate analgesic effect.