The aim of this meta-analysis was to assess the postoperative analgesic efficacy of sciatic nerve block when combined with femoral nerve block after total knee arthroplasty. Outcomes included resting pain scores (analogue scale, 0-100), intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively, and functional outcomes comprising knee flexion, distance walked, and length of stay. Twelve randomised controlled trials were included, with a total of 600 patients. When combined with femoral nerve block, sciatic nerve block significantly reduced resting pain scores at 12 h postoperatively with a mean difference of 10 (95% CI: -15 to -5; p < 0.00001). Resting pain scores at 24 h, and intravenous morphine consumption at 12 h, 24 h and 48 h postoperatively were also significantly reduced, but without clinical significance beyond 12 h and without affecting functional outcomes. In conclusion, sciatic nerve block confers additional postoperative analgesia within the first 12 postoperative hours compared with femoral nerve block alone for patients undergoing total knee arthroplasty.