Comparative Study Between Ultrasound-Guided IPACK Block (Interspace Between the Popliteal Artery and the Posterior Capsule of the Knee) with Adductor Canal Block Versus Adductor Canal Block Alone for Postoperative Pain Management in Total Knee Arthroplasty

Group I: Patients will receive the ultrasound-guided Adductor canal block (ACB) by the supervisors of the research performed just after skin closure. ACB will be performed under complete aseptic conditions. Using a high frequency (6-15MHz) linear probe of an ultrasound machine (Sonosite turbo M, Bothell, Washington, USA) covered with a sterile sheath and 100 mm needle SonoPlex (B-Braun Medical Inc., Bethlehem, PA, USA). ACB block will be performed while the patient is in a supine position at the point midway between the anterior superior iliac spine and the upper pole of the patella. The adductor canal will be located as a hyperechoic structure beneath the sartorius muscle, 100 mm needle SonoPlex will be advanced with the guidance of ultrasound in an in-plane technique and 20 ml bupivacaine (Marcaine) 0.25% will be injected.

Group II: The patients will receive ACB by the supervisors of the research just after skin closure as previously described in group I and then an IPACK block will be performed. IPACK block will be performed under complete aseptic precautions using the ultrasound machine with the high-frequency linear probe covered with a sterile sheath and 100 mm needle SonoPlex. IPACK block will be performed while the patient is in a supine position with slight knee flexion, the probe will be applied to the popliteal fossa for identification of the popliteal artery and femur. Then the probe will be distally slided for revealing the two femoral condyles followed by proximal sliding of the probe until the humps of the femoral condyles disappear and the flat metaphysis appear. A needle will be advanced from the lateral aspect and directed across the space between the popliteal artery and femur and once the needle reaches the medial edge of the femur,20 ml bupivacaine 0.25% will be injected incrementally