This prospective observational single-center study will compare the effects of ultrasound-guided meta-PENG block and suprainguinal fascia iliaca plane block in patients undergoing hip fracture surgery under spinal anesthesia.

Hip fracture surgery can cause significant pain before, during, and after the operation. Regional anesthesia techniques may help reduce pain, improve positioning for spinal anesthesia, decrease the need for additional analgesics, and support earlier mobilization.

Patients included in the study will be adults scheduled for hip fracture surgery under spinal anesthesia. According to routine clinical practice and the anesthesiologist's decision, patients will receive either ultrasound-guided meta-PENG block or ultrasound-guided suprainguinal fascia iliaca plane block. The study will not assign patients to a treatment group by randomization.

The main outcome will be pain during positioning for spinal anesthesia, measured using the Numeric Rating Scale. Additional outcomes will include postoperative pain at rest and during activity, additional analgesic consumption, patient satisfaction, mobilization time, and length of hospital stay.

Hip fractures are common, especially in older adults, and are associated with significant perioperative pain, delayed mobilization, increased analgesic requirements, and prolonged hospitalization. Effective perioperative pain control is important in this patient population because inadequate analgesia may impair positioning for spinal anesthesia, increase postoperative discomfort, and delay recovery.

Regional anesthesia techniques are frequently used as part of multimodal analgesia in patients undergoing hip fracture surgery. The suprainguinal fascia iliaca plane block is a regional block technique that may provide analgesia by affecting nerves related to the lumbar plexus, including the femoral nerve, lateral femoral cutaneous nerve, and obturator nerve. The pericapsular nerve group block and modified techniques, including meta-PENG block, aim to provide analgesia by targeting articular branches involved in hip joint innervation.

This study is designed as a prospective observational single-center study. Adult patients with ASA physical status I-III who are scheduled to undergo hip fracture surgery under spinal anesthesia will be evaluated for eligibility. Patients who provide written informed consent, or whose legal representative provides consent when applicable, will be included.

The regional block technique will be determined according to routine clinical practice and the responsible anesthesiologist's preference. Patients will not be randomized by the study protocol. Patients will be observed in two groups: those receiving ultrasound-guided meta-PENG block and those receiving ultrasound-guided suprainguinal fascia iliaca plane block.

The primary outcome of the study is pain during positioning for spinal anesthesia. Pain will be assessed using the Numeric Rating Scale, where 0 indicates no pain and 10 indicates the worst imaginable pain.

Secondary outcomes will include postoperative Numeric Rating Scale scores at rest and during activity, including back raising and hip flexion; additional analgesic consumption; patient satisfaction assessed using the OR-15 questionnaire; time to mobilization; and length of hospital stay.

Intraoperative data, spinal anesthesia medication dose, regional block and anesthesia methods, postoperative pain scores, additional analgesic requirements, mobilization time, patient satisfaction, and hospitalization duration will be recorded from the hospital information system and anesthesia records.

The study will be conducted at Sancaktepe Sehit Prof. Dr. Ilhan Varank Training and Research Hospital. The study has been reviewed and approved by the institutional scientific research ethics committee.

Inclusion Criteria:

• Age greater than 18 years
• ASA physical status I-III
• Scheduled to undergo hip fracture surgery under spinal anesthesia
• Written informed consent obtained from the patient or the patient's legal representative

Exclusion Criteria:

• Refusal to participate in the study
• ASA physical status IV-V
• Presence of central or autonomic nervous system disease
• Known allergy to the drugs used in the study

Adult patients scheduled to undergo hip fracture surgery under spinal anesthesia at Sancaktepe Sehit Prof. Dr. Ilhan Varank Training and Research Hospital will be included. Eligible patients will be ASA physical status I-III and will receive either ultrasound-guided meta-PENG block or ultrasound-guided suprainguinal fascia iliaca plane block as part of routine perioperative analgesia management.

Individual participant data will not be shared because the study includes patient clinical data and no data sharing plan was specified in the approved study protocol.