Local infiltration analgesia following total knee arthroplasty: effect on post-operative pain and opioid consumption--a meta-analysis.

Introduction: Local infiltration analgesia (LIA) is a popular method for decreasing post-operative pain after total knee arthroplasty (TKA). The goal of this meta-analysis is to compare the effect of LIA with placebo on the intensity of post-operative pain and the consumption of opioids.

Methods: A search was performed in the PubMed/MEDLINE, Cochrane, EMBASE and TRIP databases. All (quasi)-randomized controlled trials (RCTs) were included. LIA consists of intra-operative infiltration with at least one analgesic component. Data were pooled using Cochrane software.

Results: Seven placebo-controlled RCTs were included, involving 405 TKAs. On the first post-operative day, LIA provides an average decrease in VAS scores at rest of 12.3 % compared to placebo. Six RCTs studied opioid consumption in patients following TKA. There was a decrease in opioid consumption of 14.8 % compared to placebo 24 h after surgery. This suggests a reduced pain perception due to LIA. On the second post-operative day, the effect on both outcome measures was diminished and no longer significant. Heterogeneity between the studies was 71 % for pain and 39 % for opioid consumption (p = 0.002 and p = 0.0005). No major complications were reported with the use of LIA.

Conclusion: LIA might be able to decrease pain and the use of opioids on the first post-operative day following TKA. However, due to the high level of heterogeneity between the studies, no firm conclusions can be drawn.

Level Of Evidence: Meta-analysis, Level II.