Abstract
BACKGROUND: Postoperative pain after total knee arthroplasty remains substantial despite multimodal analgesia (MMA); however, whether adding liposomal bupivacaine provides clinically meaningful benefits over conventional long-acting local anesthetics within contemporary regional anesthesia–based pathways remains unclear. METHODS: In this single-center, double-blind, randomized controlled trial, 72 patients undergoing unilateral primary TKA were randomized into three groups: levobupivacaine alone (ZB), liposomal bupivacaine alone (LB), and a combination of liposomal bupivacaine and levobupivacaine (LZB). All patients received a standardized MMA protocol including an adductor canal block (ACB) and a periarticular injection (PAI). Primary outcomes were postoperative pain intensity at rest and during activity, measured by the Visual Analogue Scale (VAS). Secondary outcomes included knee range of motion (ROM), patient-controlled intravenous analgesia (PCA) utilization, sensory disturbances within the saphenous nerve distribution, postoperative complication rates, length of hospital stay, and patient satisfaction. RESULTS: Among the 62 patients who completed the study, resting pain scores showed no significant differences between groups. However, activity-related pain scores were significantly lower in the LB and LZB groups than in the ZB group between 36 and 72 h postoperatively (p < 0.05). Additionally, the time to first PCA request was significantly longer in the LB and LZB groups than in the ZB group. The LB group exhibited a higher incidence of sensory disturbances in the saphenous nerve distribution than the ZB group at 48 and 72 h postoperatively (p < 0.05). No significant differences emerged regarding ROM, opioid consumption, complication rates, length of hospital stay, or patient satisfaction. CONCLUSIONS: In patients undergoing total knee arthroplasty, incorporating liposomal bupivacaine into an analgesic regimen involving adductor canal block and periarticular infiltration provides prolonged analgesia and superior control of activity-related pain. This may facilitate early postoperative mobilization, thereby promoting early recovery. These findings support the potential of this approach in accelerating the recovery process. TRIAL REGISTRATION: This study was prospectively registered in the Chinese Clinical Trial Registry (ChiCTR2400084619) on May 21, 2024.