Epidural infusion or combined femoral and sciatic nerve blocks as perioperative analgesia for knee arthroplasty

Background. Peripheral neural blockade appears to provide effectiveanalgesia with potentially less morbidity than central neuraxialtechniques. We compared the relative benefits of combined femoral(3-in-1) and sciatic nerve block with epidural blockade forpostoperative knee arthroplasty analgesia. Methods. Sixty patients, ASA I–III, undergoing unilateralknee replacement were prospectively randomized to receive eithera lumbar epidural infusion or combined single-shot femoral (3-in-1)and sciatic blocks (combined blocks). All patients receivedstandard general anaesthesia. Visual analogue pain scores andrescue opioid requirements were recorded at four time pointspostoperatively. Patient satisfaction, morbidity, block insertiontime, perioperative blood loss and rehabilitation indices werealso assessed. Results. In both groups, pain on movement was well controlledat discharge from recovery and 6 h postoperatively but increasedat 24 and 48 h. Median (95% CI) analogue scale scores were 0(0–0), 15 (0–30), 55 (38–75) and 54 (30–67)mm for epidural block and 0.5 (0–22), 21.5 (10–28),40 (20–50) and 34.5 (21–55) mm for combined block.VAS pain scores with the combined blocks were significantlylower at 24 h (P=0.004). Total morphine usage was low in bothgroups: median epidural group 17 mg (8–32) versus combinedblocks 13 mg (7.8–27.5). Patient satisfaction was highin both groups with median (95% CI) scores of 100 (85–100),83 (70–100) and 82 (57–90) mm for epidural and 90(73–100), 100 (77–100) and 97 (80–100) mmfor combined blocks (not significant). Perioperative blood lossand rehabilitation indices were also similar. Conclusions. Combined femoral (3-in-1) and sciatic blocks offera practical alternative to epidural analgesia for unilateralknee replacements.