Local Infiltration Analgesia Versus Regional Blockade for Postoperative Analgesia in Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND Total knee arthroplasty (TKA) is one of the most commonly performed procedures while postoperative analgesia still remains challenging. The efficacy and safety of local infiltration analgesia (LIA) versus regional blockade (RB; epidural analgesia and/or peripheral nerve block) for pain management after TKA are controversial. OBJECTIVES The purpose of this meta-analysis was to determine whether LIA compared with RB would provide better postoperative pain control, consume less morphine, facilitate early functional recovery, entail a differential risk of side effects and complications, and allow a shorter length of stay. STUDY DESIGN This meta-analysis pooled all data published in randomized controlled trials (RCTs) examining the efficacy and safety of LIA versus RB following TKA. SETTING The work was performed at Affiliated Cixi Hospital, Wenzhou Medical University. METHODS Literature in English was searched using EMBASE, Medline, Cochrane Library, CINAHL, Web of Science, and Scopus from inception to April 2015. RCTs that compared LIA and RB for postoperative analgesia following TKA were included. Methodological quality was assessed using the Cochrane Back Review Group checklist, and a sensitivity analysis was performed. Sixteen RCTs with a total of 1,206 patients were finally included in our study. RESULTS The results of our meta-analysis indicate that patients managed by LIA showed significantly lower numeric rating scale (NRS) score at rest (WMD: -0.40 [-0.72, -0.07]; P = 0.02) when compared with those managed by RB. Difference of morphine consumption was not significant (WMD: -1.39 [-7.21, 4.44]; P = 0.64) between the 2 groups. In terms of early functional recovery, the LIA group showed more straight leg raise (RR: 2.90 [2.15, 3.93]; P < 0.00001) on the first postoperative day; better range of motion within one week (WMD: 4.33 [2.61, 6.05]; P < 0.00001), but not at 3 months (WMD: 1.98 [-0.02, 3.98]; P = 0.05); and comparable knee society score (WMD: -8.79 [-27.05, 9.48]; P = 0.35). Length of hospital stay of the LIA group was marginally shorter (WMD: -0.25 [-0.49, -0.01]; P = 0.05) than that of the RB group. Risk of side effects and complications were comparable between groups. LIMITATIONS The lack of a standard criterion regarding the technique details of LIA and heterogeneity resulting from the various analgesic components, dosages, and different administration methods might have posed a bias on the results. CONCLUSION Our results have indicated that LIA provided better analgesia than RB at rest and preserved quadriceps function in the immediate postoperative period, which may be beneficial to early functional recovery. And its safety profile is reliable. With the biases in our meta-analysis, a rigorous and adequately powered RCT is needed to validate our results. KEY WORDS Local infiltration analgesia, regional block, peripheral nerve block, epidural analgesia, postoperative analgesia, total knee arthroplasty, meta-analysis, randomized controlled trial.