Comparison of Spinal Anesthesia With Intrathecal Morphine Versus PENG Block With or Without Dexamethasone in Hip Arthroplasty

Comparison of the Efficacy and Safety of Three Regional Anesthesia Strategies in Patients Undergoing Elective Total Hip Arthroplasty: A Prospective, Randomized, Multicenter Clinical Trial

The goal of this clinical trial is to learn which of three regional anesthesia approaches provides better pain relief and safety for older adults having planned hip replacement surgery. Researchers will study people aged 60 years and older who are scheduled for elective total hip arthroplasty.

The main questions this study aims to answer are:

Which anesthesia method provides better pain control after surgery? Which method reduces the need for opioid pain medicines? Are there differences in side effects and recovery between the approaches? Participants will be randomly assigned to one of three groups. All participants will receive spinal anesthesia. One group will receive spinal anesthesia with intrathecal morphine. The other two groups will receive spinal anesthesia combined with a nerve block called the pericapsular nerve group (PENG) block, with or without the addition of dexamethasone.

Participants will have their pain levels measured at regular times during the first two days after surgery. Researchers will also record opioid use, time to first pain medication, ability to move after surgery, length of hospital stay, and any side effects such as nausea or itching. Blood tests will be used to measure markers of inflammation.

The results of this study may help doctors choose safer and more effective pain control strategies for people undergoing hip replacement surgery.

Postoperative pain after total hip arthroplasty is associated with increased opioid use, delayed mobilization, and a higher risk of adverse events, particularly in older adults. Spinal anesthesia with intrathecal morphine is widely used to improve postoperative analgesia; however, it may be associated with opioid-related side effects such as nausea, pruritus, urinary retention, and respiratory depression. Ultrasound-guided regional nerve blocks, including the pericapsular nerve group (PENG) block, have emerged as opioid-sparing alternatives that may provide effective analgesia while preserving motor function.

This prospective, randomized, multicenter clinical trial is designed to compare the efficacy and safety of three regional anesthesia strategies in patients undergoing elective total hip arthroplasty. Participants aged 60 years and older will be randomly assigned in a 1:1:1 ratio to one of three study groups: spinal anesthesia with intrathecal morphine; spinal anesthesia combined with a PENG block; or spinal anesthesia combined with a PENG block using perineural dexamethasone as an adjuvant.

All participants will receive standardized spinal anesthesia with ropivacaine. In the control group, intrathecal morphine will be administered as part of routine spinal anesthesia. In the intervention groups, the PENG block will be performed under ultrasound guidance using ropivacaine, with or without the addition of dexamethasone. Perioperative care, postoperative analgesic protocols, and rehabilitation pathways will be standardized across all study centers to minimize variability.

Pain intensity at rest and during movement will be assessed using a visual analog scale at predefined time points within the first 48 hours after surgery. Secondary outcomes include total opioid consumption, time to first rescue analgesia, early mobilization, length of hospital stay, incidence of opioid-related and block-related adverse events, and changes in inflammatory markers measured in peripheral blood.

The results of this study will provide comparative evidence on opioid-based versus opioid-sparing regional anesthesia strategies for hip arthroplasty and may help inform clinical decision-making aimed at improving postoperative pain control, functional recovery, and safety in older surgical patients.

Inclusion Criteria:

• Adults aged 60 to 100 years
• Scheduled for elective total hip arthroplasty
• American Society of Anesthesiologists (ASA) physical status I-III
• Ability to understand the study procedures and provide written informed consent

Exclusion Criteria:

• Known allergy or hypersensitivity to ropivacaine, morphine, or dexamethasone
• Coagulation disorders or ongoing anticoagulant therapy contraindicating spinal anesthesia or regional nerve blocks
• Infection at the site of spinal or peripheral nerve block injection
• Pre-existing neurological disorders affecting sensory or motor function
• Severe hepatic or renal insufficiency
• Chronic opioid use for more than 3 months prior to surgery
• Refusal or inability to provide informed consent