ThermoProfen is a transdermal ketoprofen patch that is integrated with a long-lasting CHADD (Controlled Heat-Assisted Drug Delivery) unit for the treatment of chronic pain associated with osteoarthritis. This study will evaluate ThermoProfen for the treatment of mild to moderate pain associated with osteoarthritis of the knee in adults.

The primary objective of the study is to compare the efficacy of ThermoProfen™ against two other experimental treatments.

The treatment may be ThermoProfen (Matrix Transdermal Ketoprofen Patch) or a patch that may or may not include ketoprofen and that may or may not provide heat.

Inclusion Criteria:

• Patient is 18 through 75 years of age
• Patient has radiographic evidence of osteoarthritis of the target knee obtained within the past year.

Exclusion Criteria:

• Patient has a known allergy to nonsteroidal anti-inflammatory drugs (NSAIDs, including aspirin).
• Patient has asthma that has been induced or made worse by the use of aspirin or NSAIDs.
• Patient has a relevant history of serious gastrointestinal disease.
• Patient, if female, is pregnant or breastfeeding or is of childbearing potential and not practicing adequate birth control.
• Patient is taking warfarin, heparin, or low molecular weight heparin.
• Patient has received oral, intramuscular, intravenous, intra-articular, or soft-tissue administration of steroids within 1 month of study enrollment (or within 2 months, if in the target joint).
• Patient has received intra-articular visco-supplementation (in target joint) within 6 months of study enrollment.