Analgesic efficacy of liposomal bupivacaine adductor canal block combined with periarticular infiltration after total knee arthroplasty: a prospective, double-blind, randomized controlled trial

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. 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. 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. 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. This study was prospectively registered in the Chinese Clinical Trial Registry (ChiCTR2400084619) on May 21, 2024.