To Compare the Efficacy and Safety of LAYLA in Osteoarthritis Patients of the Knee

Inclusion Criteria: * Patients ≥40 and ≤80 years of age * Radiographic evidence of grade 1,2 or 3 osteoarthritis based on the Kellgren \& Lawrence radiographic entry criteria * Stable osteoarthritis during 3 months * Score of 100mm Pain VAS ≤ 80mm at screening * Score of 100mm Pain VAS ≥ 40mm at baseline * Written consent form voluntarily Exclusion Criteria: * Disease of spine or other Lower limb joints that could affect fo evaluate the efficacy * History of surgery or arthroscopy of the study joint within 6 months * Trauma of study joint within 12 months * Medication of constantly(more than 1 week) corticosteroid by oral within 3 months * Diagnosed with psychical disorder, and taking medication * Medication of intra-articular injection within 3 months * Uncontrollable Hypertension patients at screening test * History of upper gastrointestinal ulceration within 6 months, History of upper gastrointestinal bleeding within 12 months * History of lower gastrointestinal bleeding within 12 months * History of coronary artery bypass, systemic lupus erythematosus or mixed connective tissue disease * Serum creatinine, ALT, AST, total bilirubin over ULN X 2.0 at screening test * History of hypersensitivity of LAYLA, CENATONE or NSAIDs * Participation in another clinical trials within 4 weeks * Medication of constantly (more than 1 week) narcotic analgesics within 3 months * Not consent about using effectual contraception method during trial * Pregnant or lactating woman * History of malignant tumor within 5 years * Investigator's judgment