Ultrasound-Guided Popliteal Plexus Block Versus Fascia Iliaca Block After Total Knee Arthroplasty

Patients in this group will receive Popliteal plexus block. Prior to Popliteal plexus block, the proximal end of the adductor canal will be identified. The transducer will be slid distally along the femoral artery until the artery deviated away from the sartorius muscle in the distal part of the adductor canal towards the adductor hiatus. The nerve block needle will be inserted from the anterolateral end of the transducer and advanced in-plane through the medial vastus muscle. The endpoint of injection will be inside the distal end of the adductor canal close to the adductor hiatus. The injection will be adjacent to the femoral artery, between the medial vastus muscle and the adductor magnus muscle. The Popliteal plexus block will be carried out with 10 mL of local anesthetic mixture, containing 50 mg of bupivacaine and 0.05 mg of epinephrine.

Patients will be placed in a supine position, and the skin will be cleaned aseptically. The inguinal ligament from the anterior superior iliac spine to the pubic tubercle will be drawn on the skin and divided into 3 parts. The injection point was 1 cm caudally from the point where the lateral and middle part of the inguinal ligament met. The skin and deep tissues were infiltrated with 1% lidocaine. A 18G nerve block needle will be inserted into the skin perpendicularly until the first (fascia lata) and second loss of resistance (fascia iliaca) will be felt. Following aspiration to exclude intravascular injection, 40 mL of 0.25% bupivacaine (1-1.5 mg/kg), which will be prepared under aseptic conditions, and then injected. Sensorial block will be evaluated using the pinprick test 20 minutes after injection for areas of the thigh innervated by the femoral, lateral cutaneous and obturator nerves.