Abstract:Objective To investigate the effects of ultrasound-guided pericapsular nerve group (PENG) block versus interscalene brachial plexus (ISB) block on postoperative recovery after shoulder arthroscopy.Methods This non-inferiority study enrolled 190 patients undergoing unilateral arthroscopic rotator cuff repair at Jiaxing Second Hospital between January 2023 and June 2024. They were randomly assigned to either the PENG group or the ISB group (95 patients each) using block randomization. Postoperatively, 6 patients were lost to follow-up in the PENG group and 4 in the ISB group, resulting in 89 patients in the PENG group and 91 in the ISB group for final analysis. The two groups were compared in terms of the postoperative Quality of Recovery-40 (QoR-40) scores, Numerical Rating Scale (NRS) scores, time to first rescue analgesia, the rescue analgesia rate, number of postoperative patient-controlled analgesia pump presses, anesthetic consumption, and adverse reactions.Results The difference in QoR-40 scores before treatment and 24 hours after surgery was smaller in the PENG group compared to the ISB group (P < 0.05). A comparison of resting NRS scores between the PENG and ISB groups at 30 minutes and 4, 8, 12, 24, and 48 hours after surgery demonstrated that they were different across the time points (P < 0.05) and between the groups (P < 0.05), with lower NRS scores in the PENG group. The change trend of NRS scores between the two groups was statistically significant (P < 0.05). The rate of rescue analgesia in the PENG group was lower than that in the ISB group (P < 0.05), and the number of patient-controlled analgesia pump presses was lower in the PENG group (P < 0.05). The incidence of rebound pain after surgery was lower in the PENG group than in the ISB group (P < 0.05).Conclusion Ultrasound-guided PENG block provides postoperative recovery comparable to ISB block after shoulder arthroscopy. It achieves effective analgesia in patients with rotator cuff injury and demonstrates a favorable safety profile.