Comparison of Pericapsular Nerve Group (PENG) Block With a Combined Femoral, Sciatic, Lateral Femoral Cutaneous Nerve Block for Postoperative Analgesia in Secondary Total Hip Arthroplasty; (REVPET)

Participants in the PENG group will first receive a sham sciatic injection; the needle will be inserted into the subcutaneous tissue and 3 ml of 0.9% NaCl will be injected. They will then receive a PENG nerve block in the supine position. A low-frequency (2-5 MHz) curvilinear ultrasound probe (BK Ultrasound) will be used to identify the anterior inferior iliac spine, the pubic eminence, and the psoas tendon with its fascial plane. A 22-gauge, 50 mm needle (SonoPlex® Pajunk) will be inserted into the fascial plane to inject 20 ml of 0.75% ropivacaine (Fresenius Kabi).

Participants in the combined group will first receive a sciatic nerve block performed with the patient in a semi-prone position, the lower limb flexed at 90° (hip and knee), elevated with a cushion placed between the legs. A straight line will be drawn between the greater trochanter and the ischial tuberosity. The sciatic nerve is located approximately at the midpoint of this line. Under ultrasound guidance, the ischial tuberosity will be identified medially, the greater trochanter laterally, the gluteus maximus muscle superficially beneath the adipose tissue, and the quadratus femoris muscle in depth. A 22-gauge, 50 mm needle will then be inserted into the fascial plane to inject 20 ml of 0.375% ropivacaine. The patient is then placed supine for femoral and lateral femoral cutaneous nerve blocks. 15 ml of local anaesthetics will be injected around the femoral nerve and 5 around the lateral femoral cutaneous nerve.