Are Adductor Canal Blocks With Bupivacaine and Added Magnesium Better at Managing Post-operative Pain Than Bupivacaine and Added Buprenorphine in Patients Undergoing Same-day Discharge Total Knee Arthroplasty?

The purpose of this study is to compare the use of magnesium and bupivacaine to buprenorphine and bupivacaine in post-operative adductor canal blocks (ACB); the study will determine if one combination can result in decreased opioid consumption and improved pain management for patients after same-day discharge total knee arthroplasty (TKA) . The investigators will assess whether the addition of magnesium to bupivacaine will decrease visual analog scale (VAS) pain scores, decrease post-operative total opioid consumption (oral morphine equivalents), decrease the incidence of post-operative nausea and vomiting (PONV), and improve patient satisfaction in comparison to when buprenorphine is added to bupivacaine.