Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Postoperative Recovery Quality in Patients Undergoing Anterior Cruciate Ligament Reconstruction

Background: Arthroscopic anterior cruciate ligament reconstruction (ACLR) is a common orthopedic surgery. Postoperative pain, inflammatory response and opioid-related adverse events impair early recovery quality. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique with potential analgesic and anti-inflammatory effects. Participants: A total of 144 eligible participants undergoing ACLR under spinal anesthesia combined with an adductor canal block will be enrolled. Methods: This prospective, randomized, double-blind, sham-controlled trial will evaluate the effects of perioperative taVNS on early postoperative recovery. Participants will be randomly assigned in a 1:1 ratio to receive active taVNS or sham stimulation. Each participant will receive three 30-minute stimulation sessions, scheduled 30-45 minutes before surgery, 6 ± 1 hours after surgery, and 18 ± 1 hours after surgery. All participants will receive standardized multimodal postoperative analgesia. The primary outcome will be the score on the 15-item Quality of Recovery (QoR-15) questionnaire at 24 hours after surgery. Secondary outcomes will include rescue opioid consumption expressed as oral morphine equivalents, pain scores measured using the Numeric Rating Scale (NRS), functional recovery, and adverse events. Conclusion: The investigators hypothesize that perioperative taVNS will improve early postoperative recovery quality after ACLR.