Effects of adductor canal block versus femoral nerve block in patients with anterior cruciate ligament reconstruction A protocol for a systematic review and meta-analysis

Objective: It is reported that both adductor canal block (ACB) and femoral nerve block (FNB) are commonly used methods for postoperative analgesia in anterior cruciate ligament (ACL) reconstruction. Currently, no record has compared the efficacy of postoperative pain relief and the influence to quadriceps strength between them. This study aims to provide a protocol to compare the efficacy and safety between ACB and FNB for the postoperative analgesia of ACL reconstruction. Methods: This study will be performed in accordance with the guideline of the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols. Online databases including PubMed, Embase, Web of Science, Cochrane Library, Wanfang database, and the Chinese National Knowledge Infrastructure database will be systematically searched from their inception up May 31, 2019. All randomized controlled trials will be included in present meta-analysis. The quality of enrolled literatures will be evaluated by using the Cochrane Collaboration Risk of bias Tool. Statistical analysis will be calculated by the Review Manager 5.3. Results: This review will investigate the efficacy and safety of ACB compared with FNB in patients undergoing ACL reconstruction. The primary outcomes are visual analog scale, cumulative opioid consumption during 24 hours after surgery, numerical rating scale, and the time to first straight-leg raise. The secondary outcomes include maximal voluntary isometric contraction, stretching torque at 3, 6 months' follow-up, and adverse effects. Conclusion: Findings of this systematic review and meta-analysis will summarize the current evidence in postoperative analgesia for ACL reconstruction and also provide implications for clinical practice.