Liposomal Bupivacaine versus Ropivacaine with Perineural Dexamethasone in Adductor Canal Block for Total Knee Arthroplasty: A Randomized Clinical Trial.

Abstract

Adductor canal block (ACB) provides effective analgesia for knee surgery while preserving quadriceps muscle strength. However, conventional local anesthetics yield only a short-lasting effect. To extend analgesia duration and reduce opioid usage, the administration of liposomal bupivacaine and perineural dexamethasone has been proposed. The present study assessed and compared the analgesic effectiveness and duration between liposomal bupivacaine and ropivacaine with perineural dexamethasone in patients undergoing total knee arthroplasty (TKA). A total of 72 patients scheduled for primary unilateral TKA were prospectively randomized to receive a single-injection ACB with either liposomal bupivacaine combined with bupivacaine hydrochloride (n = 36) or ropivacaine with perineural dexamethasone (control group, n = 36). The primary endpoint was the incidence of moderate-to-severe pain with movement at 48 hours postoperatively. The secondary outcomes included the incidence of moderate-to-severe pain both at rest and with movement at other time points, numerical rating scale (NRS) pain score, opioid consumption, quality of postoperative recovery, and adverse events. At 48 hours, the incidence of moderate-to-severe pain with movement did not differ between the liposomal bupivacaine group and the control group (47.2 versus 63.9%; relative risk 0.71; 95% confidence interval: 0.43 to 1.16; P = 0.149). Patients receiving liposomal bupivacaine showed significantly lower NRS scores both at rest and with movement at 24 and 48 hours, and consumed less opioid from zero to 24 and 24 to 48 hours (both P < 0.05). Furthermore, these patients showed an improved quality of recovery at 24 and 48 hours compared to the control group (both P < 0.05). The incidence of adverse events did not differ significantly between the two treatment groups (P > 0.05). A single-injection ACB with liposomal bupivacaine combined with bupivacaine hydrochloride did not significantly reduce the incidence of moderate-to-severe postoperative pain with movement compared to ropivacaine with perineural dexamethasone after TKA. However, this intervention significantly decreased pain intensity scores, lowered opioid consumption, and improved recovery quality without increasing adverse events compared to the control group.