To determine the therapeutic dose range of valdecoxib by comparing the efficacy of three dosing regimens (5 mg, 10 mg and 20 mg once daily) with placebo for relief of the signs and symptoms of osteoarthritis of the knee. To assess safety and tolerability of multiple doses of valdecoxib in patients with osteoarthritis of the knee.

Inclusion Criteria:

• Patients diagnosed with symptomatic OA of the knee by the American College of Rheumatology (ACR) criteria and a Functional Capacity Classification (FCC) of I - III at Screening Visit and were walking
• At the Baseline visit, eligible patients were to have Patient's Assessment of Arthritis Pain VAS ≥ 40 mm and Patient's & Physician's Global Assessment of Arthritis of "Poor" or "Very Poor"

Exclusion Criteria:

• Patients unable to walk generally