Safety and Efficacy of Celecoxib Versus Naproxen in the 6-month Treatment of Knee Osteoarthritis

Inclusion Criteria: * Osteoarthritis of the knee as defined by the American College of Rheumatology criteria in a flare state at baseline visit * Functional Capacity Classification of I-III Exclusion Criteria: * Inflammatory arthritis or gout/pseudo-gout with an acute flare within the past 2 years (subjects with fibrositis or fibromyalgia will not be excluded) * Received acetaminophen within 24 hours of the baseline visit * Acute joint trauma at index joint within the past 3 months with active symptoms * History of gastrointestinal (GI) perforation, obstruction, or bleeding * Diagnosed or treated for GI ulcer within 60 days prior to first dose of study medication * Received corticosteroids or hyaluronic acid within certain timeframe before study