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.