Adductor Canal Block vs Liposomal Bupivacaine Periarticular Injection in Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND: This study compares postoperative pain scores and functional outcomes between liposomal bupivacaine peri-articular injection (LB-PAI) vs a single-shot adductor canal block (ACB) using bupivacaine HCl in patients undergoing primary total knee arthroplasty (TKA). METHODS: This is a randomized controlled trial of 56 patients who were treated with TKA for arthritis. Patients were randomized to receive an intraoperative LB-PAI (n = 27) or preoperative ACB using bupivacaine HCl (n = 29). Both groups were otherwise given our institutional standard multimodal pain protocol. Data on Visual Analog Scale (VAS) pain scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, knee range of motion, postoperative ambulation distance, hospital length of stay, and opioid use were collected. The total cost of each intervention was compared at the conclusion of the study. RESULTS: Age, gender, or body mass index was similar between groups. Compared to the ACB group, the LB-PAI group trended to lower average VAS pain scores on postoperative days 0, 1, and 2 (average difference [95% confidence interval] = −0.5 [−0.7, 1.7], −1.0 [−0.1, 2.0], −0.2 [−0.8, 1.3]), and identical average VAS pain scores on postoperative days 4 and 7. These differences and all postoperative outcome measures were not statistically significant at any time point. A single 266-milligram vial of liposomal bupivacaine costs $351, and a single-shot ACB costs $893 at our institution. CONCLUSIONS: This randomized controlled trial shows similar postoperative pain control, functional outcomes, and opioid use between LB-PAI and a single-shot ACB in patients undergoing primary TKA. However, the single-shot ACB costs $542 more than the LB-PAI at our institution.