Meta-analysis of epidural analgesia versus peripheral nerve blockade after total knee joint replacement

BACKGROUND: Postoperative pain after major knee surgery can be severe. Our aim was to compare the outcomes of epidural analgesia and peripheral nerve blockade (PNB) in patients undergoing total knee joint replacement (TKR). Moreover, we aimed to compare outcomes of adductor canal block (ACB) with those of femoral nerve block (FNB) after TKR. METHODS: We conducted a systematic search of electronic information sources, including MEDLINE; EMBASE; CINAHL; and the Cochrane Central Register of Controlled Trials (CENTRAL). We applied a combination of free text and controlled vocabulary search adapted to thesaurus headings, search operators, and limits in each of the above databases. Pain intensity assessed on visual analogue scale (VAS), nausea and vomiting, systolic hypotension, and urinary retention was the reported outcome parameters. RESULTS: We identified 12 randomised controlled trials (RCTs) comparing outcomes of epidural analgesia and PNB reporting a total of 670 patients. There was no significant difference between two groups in VAS scores at 0–12 h (MD -0.48; 95% CI -1.07–0.11, P = 0.11), 12–24 h (MD 0.04; 95% CI -0.81–0.88, P = 0.93), and 24–48 h (MD 0.16; 95% CI -0.08–0.40, P = 0.19). However, epidural analgesia was associated with significantly higher risk of postoperative nausea and vomiting (RR 1.65; 95% CI, 1.20–2.28, P = 0.002), hypotension (RR 1.76; 95% CI, 1.26–2.45, P = 0.0009), and urinary retention (RR 4.51; 95% CI, 2.27–8.96, P<0.0001) compared to PNB. Moreover, pooled analysis of data from 6 RCTs demonstrated no significant difference in VAS score between ACB and FNB at 24 h (MD -0.00; 95% CI, -0.56–0.56, P = 0.99) and 48 h (MD -0.06; 95% CI, -0.14–0.03, P = 0.23). CONCLUSIONS: PNB is as effective as epidural analgesia for postoperative pain management in patients undergoing TKR. Moreover, it is associated with significantly lower postoperative complications. ACB appears to be an effective PNB with similar analgesic effect to FNB after TKR. Future RCTs may provide better evidence regarding knee range of motion, length of hospital stay, and neurological complications.