ACB and iPACK Blocks With Intravenous Dexamethasone and Perineural Dexmedetomidine in Total Knee Arthroplasty

This prospective randomized controlled trial aims to compare the analgesic efficacy and safety of three adjuvant strategies for ultrasound-guided Adductor Canal Block (ACB) and iPACK block in patients undergoing elective total knee arthroplasty under spinal anesthesia. All participants will receive standardized spinal anesthesia with 0.5% ropivacaine combined with ACB and iPACK blocks using 0.2% ropivacaine. Patients will be randomized into one of three groups: standard ACB + iPACK without adjuvants, ACB + iPACK with intravenous dexamethasone 8 mg, or ACB + iPACK with intravenous dexamethasone 8 mg combined with perineural dexmedetomidine added to both regional blocks. The primary outcome will be total postoperative opioid consumption during the first 48 hours after surgery expressed as intravenous morphine equivalents. Secondary outcomes will include pain intensity at rest and during movement, duration of analgesia, time to first rescue analgesia, quadriceps muscle strength, early mobilization, adverse events, inflammatory markers, and length of hospital stay.

Inclusion Criteria: * Age between 60 and 100 years * Scheduled for elective primary unilateral total knee arthroplasty * American Society of Anesthesiologists (ASA) physical status I-III * Ability to understand study procedures and provide written informed consent * Eligibility for spinal anesthesia and ultrasound-guided regional anesthesia according to institutional standards Exclusion Criteria: * Known allergy or hypersensitivity to ropivacaine, dexamethasone, dexmedetomidine, or any study-related medication * Contraindications to spinal anesthesia or peripheral nerve blocks * Coagulation disorders or anticoagulant therapy preventing safe regional anesthesia * Infection at the planned puncture site or systemic infection * Severe neurological disorders affecting lower limb sensory or motor function * Severe hepatic, renal, or uncontrolled cardiovascular disease * Clinically significant bradycardia or advanced atrioventricular conduction abnormalities * Chronic opioid use for more than 3 months before surgery * Uncontrolled diabetes mellitus or contraindications to dexamethasone administration * Inability or refusal to provide written informed consent