Min Xu,1 Sheng Wang,1 Yan Meng,1 Chen Gao,1 Lin Liu,1 Ji Yuan,1 Sheng Ding,1,2 Xiaoqing Chai,1 Keqiang He1 

1Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China; 2Graduate School,Bengbu Medical University, Bengbu, Anhui, People’s Republic of China

Correspondence: Keqiang He, Department of Anesthesiology, The First Affiliated Hospital of University of Science and Technology of China, No. 17 Lujiang Road, Luyang District, Hefei, 230001, People’s Republic of China, Email doctorhector@ustc.edu.cn Xiaoqing Chai, Department of Anesthesiology, The First Affiliated Hospital of University of Science and Technology of China, No. 17 Lujiang Road, Luyang District, Hefei, 230001, People’s Republic of China, Email xiaoqingchai@163.com

Purpose: This study aimed to compare the analgesic efficacy of liposomal bupivacaine with that of traditional ropivacaine in adductor canal blocks for patients undergoing knee arthroplasty.
Patients and Methods: A total of 119 consenting participants, who were scheduled for elective knee arthroplasty (including total knee replacement and unicompartmental knee replacement) under general anesthesia, were randomly assigned to either receive an ultrasound-guided adductor canal block with ropivacaine or liposomal bupivacaine. The primary endpoint of this study was the pain scores at 2, 24, 48, and 72 hours post-surgery. Secondary outcomes included nausea, vomiting, and pruritis, the ability to engage in physiotherapy on the first day after surgery, postoperative exercise, patient satisfaction with anesthesia, postoperative recovery index, and patient-controlled analgesic presses (12– 48 hours) for both groups.
Results: The Visual Analog Scale (VAS), assessed from 24 to 72 hours post-follow-up, demonstrated that patients receiving ropivacaine had higher median VAS scores compared to those in the liposomal bupivacaine group, both at rest and during exercise. The weighted AUC numerical rating scale pain scores whether at rest or move in the liposomal bupivacaine group was lower than the standard bupivacaine group with statistical significance. Whether it is 0– 24 hours (Rest 58.00 [53.75, 69.00] vs 48.00 [46.50, 58.00]; Move:57.00 [46.00, 59.00] vs 36.00 [35.00, 48.00]) or 0– 72 hours (Rest 214.00 [197.75, 237.00] vs 165.00 [143.50, 180.00]; Move:202.00 [190.00, 215.75]vs.156.00 [131.00, 178.00]) From 12 to 48 hours, the ropivacaine group had a significantly higher number of PCIA presses. The liposomal bupivacaine group also achieved greater pain-free bending angles and walking distances compared to the ropivacaine group.
Conclusion: Liposomal bupivacaine used in adductor canal block provides extended pain relief in knee arthroplasty patients, aiding early rehabilitation.

Keywords: nerve block, liposomal bupivacaine, analgesia, pain measurement, arthroplasty, replacement, knee