Adductor Canal Block Versus Femoral Nerve Block in Total Knee Arthroplasty: Network Meta-Analysis.

OBJECTIVES: The quality of postoperative analgesia in total knee arthroplasty is crucial for patient recovery, rehabilitation, and hospital stay duration. In line with the above, а single-shot adductor canal block has been considered as an improved method over continuous femoral nerve block. However, continuous adductor canal block and single-shot femoral nerve block have been not adequately addressed in the discussion. This study aimed to compare the effectiveness of various types of adductor and femoral nerve blocks on clinically relevant outcomes in patients following total knee arthroplasty.

METHODS: A systematic review and network meta-analysis were conducted following "PRISMA-NMA" and Cochrane Handbook guidelines. The eligibility criteria included randomized trials and, where these were lacking for a comparison, nonrandomized studies involving adults undergoing primary total knee arthroplasty, comparing single-shot adductor canal block, continuous adductor canal block, single-shot femoral nerve block, and continuous femoral nerve block.

RESULTS: A total of 36 studies involving 3308 patients were included. Single-shot adductor canal block showed higher pain scores and opioid consumption but better functional recovery at 24 h compared with continuous femoral nerve block. However, this trend vanishes by the 48 h assessment postsurgery. Continuous adductor canal block required higher opioid consumption but better functional recovery and shorter hospital stay compared with continuous femoral nerve block. Single-shot adductor canal block showed higher pain scores but comparable opioid consumption and functional recovery to continuous adductor canal block.

DISCUSSION: The shift from continuous femoral nerve block to single-shot adductor canal block as the preferred method for pain relief after total knee arthroplasty may be premature. While the latter improves mobility, it falls short in pain control and does not shorten hospital stays. Continuous adductor canal block shows promise but is currently underappreciated, and single-shot femoral nerve block is often overshadowed by other techniques in regional anesthesia. Further high-quality, multicenter randomized controlled trials are needed to validate these findings.