PENG Block vs PENG Plus Periarticular Injection vs Periarticular Injection in Older Adults

Comparison of Pericapsular Nerve Group (PENG) Block, PENG Block Plus Periarticular Injection, and Periarticular Injection Alone for Postoperative Pain Management in Older Adults Undergoing Hip Surgery: A Randomized Controlled Trial

Pain after hip surgery is common in older adults and may limit early mobilization, increase the need for opioid medications, and contribute to complications such as delirium, nausea, or prolonged hospital stay. Effective postoperative pain management that preserves muscle strength and supports early rehabilitation is especially important in this population.

Several analgesic strategies are currently used after hip surgery. Periarticular injection (PAI), administered by the surgeon during the procedure, is commonly used as part of standard care. The pericapsular nerve group (PENG) block is a newer ultrasound-guided regional anesthesia technique that targets the sensory nerves of the hip joint while sparing motor function. It may provide effective pain relief and facilitate early mobilization. However, it is unclear whether PENG block alone is superior to periarticular injection, and whether combining both techniques provides additional benefit.

The aim of this randomized controlled clinical study is to compare three postoperative analgesic strategies in older adults undergoing hip surgery: PENG block alone, PENG block combined with periarticular injection, and periarticular injection alone. Participants will be randomly assigned to one of three study groups.

The primary hypothesis is that regional anesthesia with a PENG block, either alone or combined with periarticular injection, will provide superior postoperative pain control compared with periarticular injection alone. A secondary hypothesis is that the combination of PENG block and periarticular injection will offer additional analgesic benefit compared with PENG block alone.

Outcomes assessed in this study will include postoperative pain intensity, need for additional pain medications, time to first mobilization, and the occurrence of adverse events relevant to older adults, such as hypotension, excessive sedation, or postoperative delirium.

The results of this study may help determine the most effective and practical analgesic strategy for hip surgery in older adults and support evidence-based optimization of postoperative pain management.

Postoperative pain following hip surgery is a major clinical challenge in older adults and is associated with delayed mobilization, increased opioid consumption, higher risk of delirium, and prolonged hospitalization. Analgesic strategies that provide effective pain relief while preserving motor function are particularly important to support early rehabilitation and reduce postoperative complications in this vulnerable population.

Periarticular injection (PAI), administered intraoperatively by the surgeon, is widely used as part of multimodal analgesia after hip surgery and is considered standard practice in many institutions. The pericapsular nerve group (PENG) block is a relatively new ultrasound-guided regional anesthesia technique designed to selectively block the sensory innervation of the anterior hip capsule while sparing motor nerves. Early clinical data suggest that the PENG block may improve postoperative analgesia and facilitate early mobilization; however, its comparative effectiveness relative to periarticular injection, as well as the potential benefit of combining both techniques, remains insufficiently studied.

This study is designed as a prospective, randomized, controlled, three-arm clinical trial comparing different postoperative analgesic strategies in older adults undergoing hip surgery. Eligible participants will be randomly assigned to one of three groups:

1. PENG block alone,
2. PENG block combined with periarticular injection, or
3. periarticular injection alone. The PENG block will be performed under ultrasound guidance by an experienced anesthesiologist prior to surgery using a standardized technique. Periarticular injection will be administered intraoperatively by the operating surgeon according to a standardized institutional protocol. Apart from the assigned analgesic strategy, all participants will receive standardized anesthesia and postoperative multimodal pain management to minimize confounding factors.

The primary objective of the study is to compare the effectiveness of these three analgesic strategies in controlling postoperative pain after hip surgery in older adults. Secondary objectives include assessment of opioid consumption, time to first mobilization, functional recovery, and patient comfort. Safety outcomes will also be evaluated, with particular attention to adverse events relevant to older adults, including hypotension, bradycardia, excessive sedation, nausea, vomiting, and postoperative delirium.

The results of this study are expected to provide clinically meaningful evidence on whether the PENG block offers advantages over standard periarticular injection and whether combining both techniques yields additional benefit. These findings may inform clinical decision-making and contribute to the optimization of postoperative pain management strategies for older adults undergoing hip surgery.

Inclusion Criteria:

• Age 65 years or older
• Scheduled for elective or emergency hip surgery (e.g., hip fracture fixation or hip arthroplasty)
• ASA physical status I-III
• Ability to communicate pain intensity using the NRS scale
• Written informed consent obtained from the patient or legal representative

Exclusion Criteria:

• Patient refusal or inability to provide informed consent
• Allergy, intolerance, or contraindication to any study medication: ropivacaine
• Pre-existing neurological deficit or neuropathy of the affected limb
• Coagulopathy (INR >1.5, platelets <100,000/µL) or current therapeutic anticoagulation that contraindicates regional anesthesia
• Infection at or near the injection site
• Severe hepatic or renal impairment
• History of chronic opioid use (daily opioids >30 days before surgery)
• Cognitive impairment or delirium precluding reliable pain assessment
• BMI > 40 kg/m² (if you want to exclude for technical difficulty)
• Patients receiving another regional nerve block for hip surgery
• Pregnancy or breastfeeding
• Participation in another interventional clinical trial within 30 days