One hundred and six patients with knee osteoarthritis were randomly assigned to receive either oxycodone-acetaminophen (OA; n=54) or celecoxib (n=52) therapy after total knee arthroplasty surgery. The primary outcome measured was pain at rest via the visual analog scale (VAS). Secondary outcomes of interest included pain at flexion (VAS score), patient-controlled analgesia (PCA) consumption, patients' satisfaction score, and Hospital for Special Surgery (HSS) knee score. Pain outcomes were assessed up to 7 days post-total knee arthroplasty and, while patient satisfaction and HSS functional scores were assessed up to 3 months post-intervention. Overall, the results reveal that OA is superior to celecoxib in terms of pain relief at rest and during knee flexion.