Lateral Femoral Cutaneous Nerve and Pericapsular Nerve Group (PENG) Blocks Versus Suprainguinal Fascia Iliaca Block in Postoperative Analgesia of Hip Fractures: a Prospective, Controlled, Randomized and Double Blind Study

Postoperative pain in hip fractures is challenging and requires adequate management. In this scenario, peripheral nerve blocks present superior results to systemic analgesia, minimizing the use of opioids and their adverse effects. The lumbar plexus is responsible for the nociception of the hip joint through the femoral, obturator, and accessory obturator nerves, besides being responsible for the sensory innervation of the lateral aspect of the thigh through the lateral femoral cutaneous nerve. Due to this intricate network, several regional techniques have already been proposed. However, the best analgesic approach is still unknown. Ultrasound-guided suprainguinal fascia iliaca block (SIFIB), which addresses the femoral and lateral femoral cutaneous nerves, and ultrasound-guided pericapsular nerve group block (PENG), which addresses terminal branches of the femoral and accessory obturator nerves, are techniques currently used successfully in the context of analgesia for hip surgery. PENG block generates less motor impairment of the quadriceps, which can be significant in terms of mobility and rehabilitation. Both techniques show similar analgesic results in the still scarce literature, but SIFIB has shown slight advantage in some scenarios. However, the PENG block does not reach the lateral cutaneous nerve, which may lead to greater postoperative pain perception. In an attempt to fill this knowledge gap, the investigators propose a study to analyze whether the association between PENG block and lateral femoral cutaneous nerve block (LFCNB) promotes postoperative analgesia equal to SIFIB in a population of adults with hip fractures. This will be a prospective, controlled, randomized, double blind study. Patients with hip fractures (femoral neck, transtrochanteric and subtrochanteric) who will undergo surgical treatment (hip arthroplasty and osteosynthesis with intramedullary nails or screws) will be recruited and randomly allocated into two groups: control (C) and experimental (E). In group C, patients will undergo SIFIB with 30 ml of 0.5% ropivacaine, and to maintain blinding they will also undergo PENG and LFCNB with 20 ml and 10 ml of saline, respectively. In group E, patients will receive the PENG block associated with LFCNB, with 20ml + 10ml of 0.5% ropivacaine, respectively, and 30 ml of saline solution in the SIFIB. After performing the blocks, all patients will undergo spinal anesthesia, with intrathecal injection of 10mg of 0.5% isobaric bupivacaine. As a primary objective, the investigators will evaluate dynamic pain (passive elevation of the leg at 15°) using the Numeric Rating Scale (0-10), 6 hours, 12 hours and 24 hours after spinal anesthesia.