Continuous Local Infiltration Analgesia for Pain Control After Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials

A total knee arthroplasty (TKA) has always been associated with moderate to severe pain. As more research is conducted on the use of continuous local infiltration analgesia (CLIA) to manage pain after a TKA, it is necessary to reassess the efficacy and safety of the TKA method. The purpose of this systematic review and meta-analysis of randomized controlled trials was to evaluate the efficacy and safety of pain control of CLIA versus placebo after a TKA. In January 2015, a systematic computer-based search was conducted in the Medline, Embase, PubMed, CENTRAL (Cochrane Controlled Trials Register), Web of Science, Google database, and Chinese Wanfang databases. This systematic review and meta-analysis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement criteria. The primary endpoint was the visual analog scale score after a TKA with rest or mobilization at 24, 48, and 72 hours, which represents the effect of pain control after TKA. The complications of infection, nausea, and whether it prolonged wound drainage were also compiled to assess the safety of CLIA. RevMan 5.30 software was used for the meta-analysis. After testing for publication bias and heterogeneity across studies, data were aggregated for random-effects modeling when necessary. Ten studies involving 735 patients met the inclusion criteria. The meta-analysis revealed that continuous infusion analgesia provided better pain control with rest at 24 hours (mean difference [MD] −12.54, 95% confidence interval [CI] −16.63 to 8.45), and with mobilization at 24 hours (MD −18.27, 95% CI −27.52 to 9.02) and 48 hours (MD −14.19, 95% CI −21.46 to 6.93). There was no significant difference with respect to the visual analog scale score at 48 hours (MD −6.15, 95% CI −13.51 to 1.22, P = 0.10) and 72 hours (MD −3.63, 95% CI −10.43 to 3.16, P = 0.29) with rest and at 72 hours with mobilization (MD −4.25, 95% CI −16.27 to 7.77, P = 0.49). However, CLIA increased the rate of infection (relative risk [RR] 3.16, 95% CI 1.18–8.50, P = 0.02) and the rate of nausea or vomiting (RR 0.60, 95% CI 0.37–0.96, P = 0.03). There were no significant differences in the length of hospital stay (MD −0.34, 95% CI −1.09 to 0.42, P = 0.38), deep venous thrombosis (RR 1.02, 95% CI 0.30 to 1.41, P = 0.99), or duration of surgery (MD 1.20, 95% CI −4.59 to 6.98, P = 0.69). On the basis of the current meta-analysis, CLIA was more efficacious for reducing postoperative pain than the placebo at 24 hours with rest and at 24 and 48 hours with mobilization, but it increased the risk of infection. However, CLIA did not prolong the length of hospital stay or the duration of surgery. There was also a higher heterogeneity of different analgesic drugs mixed and a high risk of selection bias in this analysis; therefore, more high-quality randomized controlled trials with standardized CLIA are necessary for proper comparisons of this technique with other methods.