Inclusion Criteria:

• Informed consent signed and dated
• Age > 45 years
• Class I-III OA of the knee and subject meets American College of Rheumatology (ACR) clinical classification criteria for osteoarthritis of the knee

Exclusion Criteria:

• Skin lesions or dermatological diseases in the treatment area
• Directly or indirectly involved in the conduct and administration of this study
• Received any investigational medicinal product within 30 days prior to Screening Visit or participation in any previous clinical study with Diractin®
• Pregnancy or lactation
• Residents of psychiatric wards, prisons or other state institutions
• Malignancy within the past 2 years
• Depressive disorders requiring treatment with tricyclics, treatment with other antidepressants must be stable for 3 months prior to screening and throughout the study
• Epilepsy
• Schizophrenia
• Neuropathic pain and any other pain condition requiring chronic use of pain medication
• Known hypersensitivity or allergy (including photoallergy) to NSAID´s including ketoprofen, celecoxib, sulfonamides and ingredients used in pharmaceutical products including galactose
• Peripheral arterial disease and/or cerebrovascular disease
• History of stroke or myocardial infarction
• Congestive Heart failure NYHA Class II-IV
• History of pancreatitis or peptic ulcers;
• Inflammatory GI disease (e.g. M. Crohn, colitis ulcerosa)
• Serum creatinine levels > 2.5 milligrams/deciliter (mg/dL)
• ALT or AST levels ≥ 5 times the ULN
• Unable to discontinue analgesic therapy including opioids, NSAID´s, tramadol, muscle relaxants, gabapentin, pregabalin, duloxetine, venlafaxine, capsaicine or other drugs approved or used for the treatment of pain for the duration of the study