0.25% Bupivacaine Versus a Mixture of 0.25% Bupivacaine and 1.3 % Liposomal Bupivacaine in Patients Undergoing Tka

This is an assessor-blinded randomized controlled trial evaluating the efficacy of liposomal bupivacaine (Exparel) in patients undergoing Total Knee Arthroplasty. The primary outcome of this study is the proportion of patients "fit to discharge" on postoperative day one. Recently, liposomal bupivacaine (LB) (Exparel) was introduced into clinical practice, using a lipid-based depot (DepoFoam) technology for sustained release of bupivacaine. LB (Exparel) uses this technology to extend the delivery of bupivacaine, a local anesthetic that has been used in clinical practice for decades for peripheral nerve block, spinal, and epidural analgesia and anesthesia. This formulation prolongs the duration of analgesia of bupivacaine for up to 72 hours with a single injection. The study was designed to compare two of our current standard therapies: 1. Adductor Canal Block + Tissue Infiltration (lateral, medial and femoral compartment + posterior capsule tissue infiltration using 0.25% bupivacaine; and 2. Adductor Canal Block + Tissue Infiltration (lateral, medial and femoral compartment + posterior capsule tissue infiltration) using 1:1 mixture of 1.3% LB (Exparel) + 0.5% bupivacaine HCl mixture.