Dose adductor canal block combined with local infiltration analgesia has a synergistic effect than adductor canal block alone in total knee arthroplasty: a meta-analysis and systematic review

Background: Both adductor canal block (ACB) and local infiltration analgesia (LIA) are effective procedures for postoperative pain control in total knee arthroplasty (TKA) without motor blockade. However, whether ACB combined with LIA has synergistic effect than ACB alone remains unknown. We hypothesized that ACB combined with LIA would have better postoperative pain control, less rescue opioid consumption and faster rehabilitation than ACB alone, without higher adverse event rate. Methods: We conducted a meta-analysis to identify relevant articles involving ACB+LIA and ACB alone in patients who underwent TKA from online register databases such as PubMed, Medline, Embase, Web of Science, and the Cochrane Library. The primary outcomes were visual analog scale (VAS) score and morphine consumption. Secondary outcomes were postoperative range of motion (ROM) and adverse event rate. Results: According to the keyword search from online register databases, a total of 879 articles were identified, of which six articles that met the inclusion criteria were determined as eligible. There were three randomized controlled trials (RCTs) and three non-randomized prospective studies. As compared to the ACB alone group, the ACB+LIA group had lower VAS at rest on postoperative day 0 and 1, as well as significantly less morphine consumption on postoperative day 0 and 1 and significantly better postoperative ROM. There were no significant differences in adverse event rate. Conclusion: As compared to ACB alone, ACB+LIA provides better analgesia and faster functional rehabilitation in patients who underwent TKA.