Efficacy of direct adductor canal block in pain control and sparing opioid consumption after total knee arthroplasty: a randomized controlled trial

Background The adductor canal block has been proven effective in controlling postoperative pain, but it requires additional space and manpower. In contrast, intraoperative or direct adductor canal block (D-ACB) is performed during the surgical procedure, eliminating additional time and cost. The purpose of this study was to evaluate the efficacy and safety of D-ACB. The authors hypothesized that adding D-ACB to periarticular injection (PAI) would help control postoperative pain and reduce opioid use after TKA without causing major side effects. Methods Among patients scheduled to undergo primary TKA from September 2023 to February 2024, 38 patients in the PAI-alone group and 40 patients in the D-ACB + PAI group were eligible for analysis. The PAI-alone group received only PAI, while the D-ACB + PAI group received an additional ACB intraoperatively. Pain VAS scores and opioid consumption from the day of operation to postoperative day 5 were collected. Neurotoxicity and cardiotoxicity were considered major adverse events and were monitored along with postoperative motor weakness and fall-down events. Results The D-ACB + PAI group used less opioid compared to the PAI-alone group. No major adverse effects were observed in either group during the perioperative period. Conclusion Intraoperative direct ACB demonstrated an opioid-sparing effect when combined with PAI. By performing ACB intraoperatively, no additional space, cost, or manpower was required, and patients did not need an additional catheter for pain control. Direct ACB is a simple and safe procedure that can facilitate recovery after TKA. Trial registration This study was retrospectively registered at the Clinical Research Information Service on April 5, 2024 (KCT0009311).