Liposomal Bupivacaine in Adductor Canal Blocks (ACB)

Inclusion Criteria: 1. The subject is scheduled for elective unilateral primary TKA 2. The subject is ≥ 18 years 3. The subject's primary anesthesia care team has planned for a neuraxial anesthetic (i.e. spinal, epidural or combined-spinal epidural) 4. The patient consents for an adductor canal block 5. Willing and able to sign an informed consent. Exclusion Criteria: 1. Patients unwilling or unable to consent to participate in the study. 2. Prisoners. 3. Pregnancy. 4. Reported to have mental illness or belonging to a vulnerable population. 5. Subject is \< 18 years of age. 6. Patients receiving general anesthesia for the total knee arthroplasty. 7. Subject has impaired decision-making capacity per discretion of the Investigator. 8. Any condition for which the primary anesthesia care team deems neuraxial anesthesia inappropriate. 9. Significant pre-existing neuropathy on the operative limb. 10. Significant chronic pain disorders (i.e. fibromyalgia, complex regional pain syndrome I \& II, among others). 11. Subject has sustained a significant trauma to the operative knee. 12. Chronic Opioid Use (daily or almost daily use of opioids for \> 3 months). 13. Known hypersensitivity and/or allergies to local anesthetics. 14. Previous surgery on the affected knee excluding arthroscopic or open meniscectomy. 15. Patients with impaired renal function such that they cannot receive IV Toradol.