Pericapsular Nerve Group Block Versus Intrathecal Morphine for Pain After Hip Surgery

Pain after hip replacement surgery is often severe and is commonly treated with opioids, which may cause nausea, vomiting, sedation, difficulty passing urine and slow breathing. This study will compare two ways of controlling pain in adults having hip surgery under spinal anesthesia. One group will receive morphine added to the spinal injection. The other group will receive an ultrasound-guided pericapsular nerve group (PENG) block, in which local anesthetic is injected near the nerves that carry pain signals from the hip joint. Participants will be assigned to one of the two groups by chance. Sixty-four adults aged 18 to 65 years will take part, with 32 in each group. Pain scores at rest and during movement, the total amount of morphine used through a patient-controlled pump, the time until the first request for extra pain medicine, the amount of additional paracetamol used, side effects such as nausea and vomiting, and complications related to the block will be compared between the groups during the first 48 hours after surgery.

Inclusion Criteria: * Age 18 to 65 years * American Society of Anesthesiologists physical status I, II or III * Scheduled for unilateral hip surgery under spinal anesthesia, including hip fracture surgery and hip replacement surgery * Able to understand and use the Visual Analog Scale and the patient-controlled analgesia device * Written informed consent Exclusion Criteria: * Refusal to participate * Known allergy or hypersensitivity to local anesthetics, morphine or paracetamol * Any contraindication to spinal anesthesia, including coagulopathy, ongoing anticoagulant therapy, thrombocytopenia, infection at the puncture site, or raised intracranial pressure * Local infection or previous surgery at the pericapsular nerve group block site * Chronic opioid use or history of substance use disorder * Chronic pain requiring regular analgesic treatment before surgery * Cognitive impairment, psychiatric disorder or communication difficulty preventing use of the pain scales * Pre-existing neurological deficit in the operative lower limb * Body mass index above 40 kg/m² * Pregnancy or breastfeeding