<qa>  How many groups were allocated by computerized block randomization according to a computer generated randomizationThe patients were allocated into 2 groups by computerized block randomization according to a computer generated randomization. Treatment allocations were contained in sealed envelopes that were opened after patient enrollment. Patients received either 8 mg of intravenous IV ondansetron or 0.3 mg of IV ramosetron 10 minutes before spinal anesthesia and intrathecal morphine. All of the unilateral TKAs were done by one orthopedic surgeon using the same minimally invasive surgical technique and the same prosthesis. 