Fascia Iliaca Compartment Block and Tramadol for Analgesia in Hip Fracture

Background With the global aging population, the incidence of hip fractures continues to rise. In the United States, over 300,000 cases occur annually among individuals aged 65 years or older. The incidence of hip fractures in Europe ranges between 307 and 1269 per 100,000 population. Mortality rates one year after a hip fracture are alarmingly high, ranging from 19.7% to 34.8%, making hip fractures a significant public health issue. It is estimated that the global number of hip fracture cases will increase to 2.6-7.3 million by 2025 and 4.5-21.3 million by 2050 . Optimizing treatment pathways for hip fractures, promoting accelerated postoperative recovery, and improving patient outcomes are therefore critical.

Early pain management intervention can alleviate pain, reduce anxiety, improve sleep, and significantly decrease complications and mortality associated with hip fractures . Currently, intravenous tramadol is a commonly used analgesic. Tramadol, a synthetic opioid, acts as a μ-opioid receptor agonist with weak affinity and inhibits serotonin (5-HT) and norepinephrine (NE) reuptake, exerting dual analgesic effects . It is increasingly replacing high-affinity opioids for the treatment of moderate-to-severe acute and chronic pain globally. However, tramadol has adverse effects, including sweating, dizziness, nausea, vomiting, appetite loss, urinary retention, and risks of addiction, misuse, and respiratory depression. Its use in hip fracture patients requires close monitoring to manage adverse effects promptly.

The pain associated with hip fractures arises from noxious stimulation of free nerve endings transmitting nociceptive and proprioceptive signals. The nerves innervating the hip skin originate from the lumbar plexus, including the femoral nerve and lateral femoral cutaneous nerve. The anterior hip joint capsule receives sensory input from the femoral and obturator nerves. Pain receptors in the anterior capsule are most densely distributed in the superior portion, while they are sparse in the posterior capsule and ligaments surrounding the hip joint.

Based on this anatomical understanding, a Supra-inguinal fascia iliaca compartment block (SiFICB) above the inguinal ligament can effectively block the femoral and lateral femoral cutaneous nerves. The spread of local anesthetics medially in the fascia iliaca compartment can also block the obturator nerve, achieving analgesia. However, fascia iliaca blocks can have adverse effects, including inadequate localization leading to poor efficacy, quadriceps weakness due to femoral nerve blockade, and local anesthetic toxicity. Ultrasound guidance can ensure accurate delivery of local anesthetics into the fascia iliaca compartment, allowing for lower concentrations and reduced adverse effects. Although studies have reported the efficacy of ultrasound-guided fascia iliaca blocks for postoperative pain relief after hip surgeries , their impact on preoperative pain caused by fracture displacement or friction of fracture ends remains underexplored.

The investigators hypothesize that an ultrasound-guided SiFICB above the inguinal ligament provides superior perioperative analgesia compared with intravenous tramadol, the current standard of care in orthopedic trauma. To test this hypothesis, the investigators design a prospective randomized controlled trial in patients undergoing hip fracture surgery, using the numerical rating scale (NRS) as the primary outcome to assess pain, to evaluate the perioperative analgesic efficacy of ultrasound-guided SiFICB by comparison to intravenous tramadol in patients with hip fractures.