The Efficacy of Continuous Adductor Canal Block Oblique Approach to Postoperative Analgesia After Total Knee Arthroplasty: A Randomized, Double-Blinded, Controlled Clinical Trial.

Background: Continuous adductor canal block (CACB) is a highly effective analgesic technique in total knee arthroplasty. The brachy axis approach (BA) is currently the common method used for CACB. Although CACB for BA offers advantages such as easy localization and operation due to clear anatomy, it has limitations such as short catheter placement and a high dislocation rate. These limitations can result in insufficient postoperative analgesia and impact patient rehabilitation. The perineural catheters placed parallel for CACB increases the difficulty of operation and the risk of puncture injury. In this study, the authors first applied the oblique approach (OA) to CACB and systematically compared the postoperative analgesic effects and adverse reactions of these two CACB methods with different puncture angles. Methods: Ninety subjects who underwent TKA were randomly assigned to receive ultrasound-guided CACB using either the OA or BA. The main outcome measured was the exercise maximum visual analog scale (VAS) score at 72 h after surgery. The main safety indicator was the rate of catheter dislocation. The data were recorded and analyzed using analysis of variance, with adjustments made for baseline characteristics. Results: There was no statistical difference in catheter placement time or postoperative resting VAS between the two groups. However, the postoperative exercise VAS and the incidence of postoperative adverse effects were lower in the OA group compared to the BA group. Conclusions: The OA of CACB applied after TKA improved the analgesic effect during the postoperative motor state compared to the BA and reduced the incidence of adverse reactions, without increasing the catheterization procedure time. Trial Registration: Chinese Clinical Trial Registry: ChiCTR2200059889.