Comparison of Genicular Nerve Block and Intraarticular Injection for Postoperative Pain in Knee Arthroscopy

The injection will be performed under ultrasound guidance by placing the patient's knee in approximately 90° of flexion with the leg hanging off the side of the bed (left). A high-frequency linear transducer ultrasound probe is placed in the superolateral corner of the patella, directed medially toward the patellofemoral joint space. In the extended leg, from anterior to posterior, the right image shows the quadriceps femoris tendon (QF), suprapatellar fat pad (SF), suprapatellar bursa (SB), prefemoral fat pad (PF), and femur (F). When the knee is flexed to 90°, the size of the suprapatellar bursa image is increased. Using an in-plane approach, the needle will be directed into the suprapatellar joint space, and 20 ml of bupivacaine 0.25% will be injected.

The transducer will be first placed parallel to the long bone shaft and moved up or down to identify the epicondyle of the long bone. The genicular arteries will be identified near the periosteal areas, confirmed by color Doppler ultrasound. Accordingly, genicular nerve block target points should be next to each genicular artery. After using color Doppler to confirm the genicular artery, the needle will be inserted in the plane of the ultrasound probe in the long-axis view. a gentle aspiration will be performed and a 2 mL injection volume will be administered.