Dexmedetomidine as an adjunct to local anesthetics in nerve block relieved pain more effectively after TKA: A meta-analysis of randomized controlled trials

Abstract

Background: Dexmedetomidine showed some potential in pain control in patients undergoing Total Knee Arthroplasty (TKA). Nerve block is a preferable alternative for postoperative analgesia after TKA, on which dexmedetomidine had an effect controversially. This study aimed to meta-analyze the available randomized controlled trials to determine the efficacy and safety of dexmedetomidine as an adjunct to local anesthetics in nerve block after TKA. Methods: PubMed, Embase, Cochrane Library, Web of science and ScienceDirect databases were searched for the randomized controlled trials (RCTs) meeting prespecified inclusion criteria up to February 1 st , 2020 . The primary outcomes included pain scores, duration of analgesia, total opioids consumption in 24 hours postoperatively, and patient satisfaction. The second outcomes were motor strength, sedation degree and postoperative nausea and vomiting, and other related complications. The methodological quality was assessed by the Cochrane risk of bias tool. Results: The initial search yielded 143 studies, of which 7 met the inclusion criteria finally. The pooled data indicated that dexmedetomidine combined with local anesthetics in nerve block in TKA could decrease postoperative pain scores at rest (SMD=-1.01[95%CI, -1.29 to -0.72], p<0.01) and at motion(SMD=-1.01[-1.25 to -0.77], p<0.01,), decrease the total opioids consumption within 24 hours(SMD=-0.63[-0.86 to -0.40], p<0.01), prolong the analgesia duration(SMD=0.90[0.64 to 1.17], p<0.01), improve motor strength(SMD=0.23[0.01 to 0.45], p=0.04) and the sedation degree (SMD=0.94[0.70 to 1.18], p<0.01), and increase the patient satisfaction(SMD=0.88[0.60 to 1.17], p<0.01) without adding nausea and vomiting(RD=-0.05[-0.11 to 0.01],p=0.14), and other related complications(RD=-0.01[-0.08 to 0.07],p=0.89), compared with local anesthetics alone in nerve block. Conclusions: It was effective and safe for dexmedetomidine as an adjunct to local anesthetics in nerve block in TKA to relieve postoperative pain, decrease total opioids consumption, prolong analgesic duration and increase patient satisfaction without increasing related complications. Based on the quality evidence we got, we recommended dexmedetomidine as a regular regimen in nerve block for patients undergoing TKA. Registration: This meta-analysis was prospectively registered on PROSPERO (International prospective register of systematic reviews) and the registering number was CRD42020169171.