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

A.Preoperative settings:

All patients will undergo preoperative assessment (including full history, clinical examination & routine preoperative laboratory investigations will be done (CBC, INR, PT, PTT, and blood chemistry like liver and kidney functions).

B.Intraoperative settings:

On arrival of the patients to the operative room, electrocardiography, non-invasive blood pressure, and pulse oximetry will be applied. Baseline parameters such as systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), heart rate (HR), and oxygen saturation (SpO2) will be recorded. An intravenous (IV) cannula will be inserted, and 500 cc lactated Ringer will be started intravenously as co-load volume. Premedication of 0.02mg/kg of midazolam IV will be given for sedation. Patients will receive spinal anesthesia by the supervisors of the research using the standard technique in a sitting position under complete aseptic conditions using betadine 10%. Then using 4ml lidocaine 2% for local skin infiltration, then introducing a spinal needle 25G (Mercury TM) till getting cerebrospinal fluid (CSF) flow. After getting the CSF flow 12.5mg of heavy bupivacaine 0.5% (Sunny Pharmaceutical Industries, Egypt) will be injected. Then the patient will lie supine with a slight inclination of the head, and then an assessment of the level of spinal anesthesia will be done using cold touch test.

Group I (Adductor canal group): 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.