Adding Dexmedetomidne to Intra-articular Local Anesthetics Results in Prolonged Analgesia After Knee Arthroscopy: A Systematic Review and Meta-analysis

Purpose: To assess the efficacy and safety of dexmedetomidine as an adjuvant to intra-articular (IA) injections of local anesthetics (LA) in adult patients undergoing knee arthroscopy. Methods: We searched MEDLINE, Embase, and Cochrane Library for randomized controlled trials (RCTs) comparing IA dexmedetomidine plus LA versus LA alone for knee arthroscopy in adults. We used the DerSimonian and Laird random-effects model for all outcomes and conducted a sensitivity analysis with the leave-one-out method, as well as a subgroup analysis for the type of LA. We used R version 4.1.2 for all statistical analyses. Results: We included 16 RCTs encompassing 799 patients, of whom 49.8% received IA dexmedetomidine. In the pooled analysis, time to first analgesia rescue was prolonged in almost 4 hours with the use of dexmedetomidine (mean difference [MD] 229 minutes; P < .001). We found statistically significant differences favoring dexmedetomidine in pain scores at rest and movement throughout the first 2, 6, 12, and 24 hours postoperatively (P < .001). Although the MD ranged from -0.3 to -0.9 cm, corresponding to a 3% to 9% reduction in pain scores, this change is not clinically significant compared with the minimal clinically important difference (MCID). Additionally, the intervention group showed a statistically significant reduction in cumulative opioid consumption over 24 hours (MD -4.5 mg; P < .001). However, this reduction did not meet the threshold for the MCID. There was no difference between groups on the incidence of hypotension (P = .190), bradycardia (P = .430), and postoperative nausea and vomiting (P = .550). Conclusions: Adding dexmedetomidine to LA in IA injections for knee arthroscopy significantly extended analgesia duration. Additionally, it lowered pain scores and opioid use, although these effects did not reach the MCID. Furthermore, this addition did not increase the risk of adverse events. Level of Evidence: Level II, meta-analysis of Level I and II studies.