Single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery: a meta-analysis of randomised placebo-controlled studies

OBJECTIVES To evaluate the efficacy and safety of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery. DESIGN Meta-analysis. DATA SOURCES AND STUDY ELIGIBILITY CRITERIA A comprehensive literature search, using Medline (1966-2014), the Cochrane Central Register of Controlled Trials and Embase databases, was conducted to identify randomised placebo-controlled trials that used a combination of single-dose intra-articular bupivacaine and morphine for postoperative pain relief. RESULTS 12 articles were included in this meta-analysis. The mean visual analogue scale (VAS) scores of the bupivacaine plus morphine group were significantly lower than those of the placebo group (weighted mean difference (WMD) -1.75; 95% CI -2.16 to -1.33; p<0.001). The VAS scores at the last follow-up time point (last VAS scores) of the bupivacaine plus morphine group were also significantly lower than those of the placebo group (WMD -1.46; 95% CI -1.63 to -1.29; p<0.001). The number of patients requiring supplementary analgesia was also significantly reduced (RR 0.60; 95% CI 0.39 to 0.93; p=0.02), while there was no significant difference in the time to first analgesic request (WMD 3.46; 95% CI -1.81 to 8.72; p=0.20) or short-term side effects (RR 1.67; 95% CI 0.65 to 4.26; p=0.29). CONCLUSIONS The administration of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery is effective for pain relief, and its short-term side effects remain similar to saline placebo.