Comparison Between Quadro-iliac Plane Block (QIPB) and Pericapsular Nerve Group (PENG) Block Combined With Lateral Femoral Cutaneous Nerve Block for Total Hip Arthroplasty: a Randomized Controlled Trial

Materials and Methods:

This prospective, randomized clinical trial will include patients aged 18-80 years with American Society of Anesthesiologists (ASA) physical status I-III who are scheduled to undergo elective unilateral primary total hip arthroplasty unde spinal anesthesia. Before enrollment, all patients will be informed about the study protocol and written informed consent will be obtained. Patients will be instructed on the use of the Numeric Rating Scale (NRS) for postoperative pain assessment, where 0 represents no pain and 10 represents the worst pain imaginable.

Patients with contraindications to spinal anesthesia, allergy to local anesthetics, coagulopathy, infection at the injection site, chronic opioid use, pre-existing neurological deficits involving the lower extremities, cognitive impairment preventing reliable communication, revision or bilateral hip arthroplasty, and refusal to participate will be excluded from the study.

Patients will be randomly allocated to one of two study groups using a computer-generated randomization sequence (https://www.randomizer.org). Randomization will be performed by a team member not involved in patient management or outcome assessment. Allocation concealment will be achieved using sequentially numbered sealed opaque envelopes, which will be opened immediately before block performance.

Upon arrival in the operating room, standard monitoring including electrocardiography, non-invasive blood pressure measurement, and pulse oximetry will be applied. Following intravenous access and preloading according to institutional practice, spinal anesthesia will be performed at the L3-L4 or L4-L5 intervertebral space using a 25-gauge Quincke spinal needle under aseptic conditions. After confirmation of free cerebrospinal fluid flow, 12-15 mg of 0.5% hyperbaric bupivacaine will be administered intrathecally. Supplemental sedation with intravenous midazolam and/or propofol may be provided when required for patient comfort.