Local infiltration analgesia (LIA) has emerged as an alternative treatment for postoperative pain after total knee arthroplasty (TKA). Its efficacy remains inconclusive with inconsistent results from previous studies and meta-analyses. There is no agreement on which local anaesthetic agent and infiltration technique is most effective and well tolerated.OBJECTIVE
The objective was to compare LIA after primary TKA with placebo or no infiltration in terms of early postoperative pain relief, mobilisation, length of hospital stay (LOS) and complications when used as a primary treatment or as an adjunct to regional anaesthesia. The role of injection sites, postoperative injection or infusion and multimodal drug injection with ketorolac were also explored.DESIGN
A systematic review and meta-analysis of randomised controlled trials (RCTs).DATA SOURCES
A literature search was performed using PubMed and SCOPUS up to September 2015.ELIGIBILITY CRITERIA
RCTs comparing LIA with placebo or no infiltration after primary TKA in terms of pain score and opioid consumption at 24 and 48 h, mobilisation, LOS and complications were included.RESULTS
In total 38 RCTs were included. LIA groups had lower pain scores, opioid consumption and postoperative nausea and vomiting, higher range of motion at 24 h and shorter LOS than no injection or placebo. After subgroup analysis, intraoperative peri-articular but not intra-articular injection had lower pain score at 24 h than no injection or placebo with the pooled mean difference of pain score at rest of −0.89 [95% CI (−1.40 to −0.38); I2 = 92.0%]. Continuing with postoperative injection or infusion reduced 24-h pain score with the pooled mean difference at rest of −1.50 [95% CI (−1.92 to −1.08); I2 = 60.5%]. There was no additional benefit in terms of pain relief during activity, opioid consumption, range of movement or LOS when LIA was used as an adjunct to regional anaesthesia. Four out of 735 patients receiving LIA reported deep knee infection, three of whom had had postoperative catheter placement.CONCLUSION
LIA is effective for acute pain management after TKA. Intraoperative peri-articular but not intra-articular injection may be helpful in pain control up to 24 h. The use of postoperative intra-articular catheter placement is still inconclusive. The benefit of LIA as an adjunctive treatment to regional anaesthesia was not demonstrated.