Adductor Canal Versus Femoral Nerve Block after Anterior Cruciate Ligament Reconstruction: A Systematic Review of Level I Randomized Controlled Trials Comparing Early Postoperative Pain, Opioid Requirements, and Quadriceps Strength.

<bold>Purpose: </bold>To systematically review the literature to compare the adductor canal block (ACB) with the femoral nerve block (FNB) following primary anterior cruciate ligament reconstruction (ACLR) in terms of early postoperative analgesic requirements and postoperative quadriceps strength.<bold>Methods: </bold>A systematic review was performed by searching PubMed, the Cochrane Library, and Embase up to August 2019 to identify randomized controlled trials that compared postoperative pain and functional outcomes in patients following primary ACLR with ACB versus FNB. The search phrase used was: adductor canal femoral nerve anterior cruciate ligament. Patients were evaluated based on analgesic consumption and quadriceps muscle strength. Study quality and risk of bias were evaluated with the Modified Coleman Methodology Score and Cochrane risk-of-bias tool respectively.<bold>Results: </bold>Five studies (all Level I evidence) were identified that met inclusion criteria, including 221 patients undergoing primary ACLR with ACB (mean age 26.8 years, 68.3% male) and 221 with FNB (mean age 28.2 years, 67.0% male). Statistical assessment for heterogeneity found for opioid consumption of ACB versus FNB groups was I2 = 97% (P < .0001). There were no significant differences in analgesic consumption within the first 24 hours following surgery between groups except in 1 study, in which patients receiving ACB required significantly greater analgesics (P < .001). Three studies using 3 different techniques to measure strength found patients receiving ACB to have significantly greater quadriceps muscle function within 24 hours of surgery when compared with patients receiving FNB (P < .05).<bold>Conclusions: </bold>In patients undergoing ACLR, the ACB may provide similar analgesic requirements, and the included studies suggest a potential advantage in preserving muscle strength at short-term (24-48 hours) follow-up when compared with FNB. However, the differences in muscle strength assessments between studies do not allow for strong conclusions.<bold>Level Of Evidence: </bold>I, systematic review and meta-analysis of Level I studies. [ABSTRACT FROM AUTHOR]