Ultrasound-guided Genicular Nerve Block in Patients Undergoing Knee Arthroscopy: A Randomized Controlled Trial.

This study was to investigate the efficacy of ultrasound-guided genicular nerve block for patients who underwent knee arthroscopy. Patients were randomized into two groups: 1. nerve block group: ultrasound-guided genicular nerve block (superomedial, superolateral and inferomedial genicular nerve, 2-ml 0.5% ropivacaine each nerve.) prior to the general anesthesia, 2. control group: no intervention prior to the general anesthesia. The measurements were pain severity at 3,6, 12, 24, 48, and 72 hours after surgery at rest and at activity(Pain severity was primary outcome at 3 hours after surgery at rest); the time for first ambulation; straight leg raise; mechanical pain threshold of the block areas; time of the surgery, anesthesia and extubation; the use of analgesics in the perioperative period and 72 hours after the surgery; the number of patients awakening from pain on the first two nights after the surgery; the length of hospital stay; postoperative adverse effects. The pain severity was performed by VAS (A 10-point visual analogue scale, 0 points painless, 10 points severe pain) and median (interquartile range; IQR). A total of 70 patients (median age: 53 y, 32 men; 35 per group) were included. Compared to the control group, the nerve block group had a lower pain VAS score at rest (2[2-2] vs. 3[2-4], P <0.01) at 3 hours, and lower pain VAS score at rest persisted for 24 hours and activity persisted for 12 hours after the surgery, also had lower intraoperative dosage of sufentanil (20±4.8 vs. 28.5±5.1 mg; P <0.001), lower requirement for analgesics for pain and lower PONV (postoperative nausea and vomiting) throughout the 72-hour observation period. There were no significant difference for the incidence of postoperative adverse effects and straight leg raise. In conclusion, ultrasound-guided genicular nerve block could reduce the pain severity after knee arthroscopy and decrease the use of intraoperative sufentanil without affecting motor function.