Efficacy and safety of single-dose local infiltration of analgesia in total knee arthroplasty: a meta-analysis of randomized controlled trials.

PURPOSE: To examine the efficacy and safety of single-dose local infiltration of analgesia (LIA) for post-operative pain relief in total knee arthroplasty (TKA) patients.

METHODS: A systematic electronic literature search (up to Aug 2013) was conducted to identify the RCTs that address the efficacy and safety of single-dose LIA in the pain management after TKA. Subgroup analysis was conducted to determine changes of visual analog score (VAS) values at six different postoperative time points. Weighted mean differences or relative risks with accompanying 95% confidence intervals were calculated and pooled using a random effect model.

RESULTS: Eighteen trials involving 1858 TKA patients met the inclusion criteria. The trials were liable to medium risk of bias. The VAS values at postoperative 2h, 4h, 6h, 12h, 24h, and 48h per patient were significantly lower in the LIA group than in the placebo group, and the former group also had less morphine consumption and better early functional recovery including range of motion, time to straight leg raise and 90° knee flexion than the latter group. No significant difference in length of hospital stay or side effects was detected between the two groups.

CONCLUSIONS: The current evidence shows that the use of single-dose LIA is effective for postoperative pain management in TKA patients, with satisfactory short-term safety. More high-quality RCTs with long-term follow-ups are required for examining the long-term safety of single-dose LIA.

LEVEL OF EVIDENCE: I, II.