A potential risk, although low, is the concern for bupivacaine toxicity. Toxicity from bupivacaine is associated with central nervous system issues (seizures) and cardiac toxicity. Toxicity is dose dependent and recommended levels should not exceed 400mg/24 hr period. With the use of bupivacaine into each surgical site, there is a theoretical risk, if administered intra-vascularly, of bupivacaine toxicity. To date, no study has evaluated the safety of liposomal bupivacaine when used in simultaneous bilateral total knee arthroplasty. The use of liposomal bupivacaine is FDA approved for infiltration of one vial into one surgical site. Other specialties have evaluated the use of one vial of liposomal bupivacaine into two surgical sites (breast augmentation) at one surgery without any adverse events.