Patients between 18-65 years and with American Society of Anesthesiologists' (ASA) Physical Status class I-II, who were scheduled for arthroscopic knee surgery, were enrolled in a randomised comparative clinical trial. Blinding or masking began in the preoperative holding unit. Exclusion criteria were psychiatric illness, younger than 18 yo, who has analgesic treatment before the surgery and known hypersensitivity to relevant drugs. All patients received a standard anaesthetic protocol; ECG, heart rate, non-invasive blood pressure, oxygen saturation and temperature were monitored. After preoxygenation, general anaesthesia was induced with sodium pentothal 4 to 7 mg/kg, 1 mcg/kg fentanyl and neuromuscular block was achieved with rocuronium 0.5 mg/kg and trachea was intubated. Anesthesia was maintained with desflurane 6% and 50% oxygen in the medical air.