 - the analgesic efficacy of a flexible ascending regimen of Q8003 compared to a low dose regimen of Q8003 3 mg2 mg and potentially up to 6 mg 4mg and to 1-2 Percocet 5 mg325 mg tablets. Study drug will be administered every 4-6 hours over a 48-hour Treatment Period to inpatients with moderate to severe postoperative pain who have undergone primary unilateral total knee arthroplasty or total hip arthroplasty. 