RecruitingPhase 3Drug trialMethadone in TKA for Post-op Pain and Opioid ReductionThis randomized, double-blind controlled trial investigates whether intraoperative IV methadone (0.15 mg/kg based on ideal body weight) reduces acute postoperative pain and opioid consumption in patients undergoing elective total knee arthroplasty under spinal anesthesia with mepivacaine.