The primary objective of the study is to assess analgesic efficacy of Impracor (Ketoprofen 10% Cream) compared to placebo for acute pain associated with OA flare of the knee.

Inclusion Criteria:

• Clinical diagnosis of OA of the knee according to the ACR criteria.
• Kellgren-Lawrence grade 2-3 disease
• Be willing to stop taking all analgesics including NSAIDs and opioids for the duration of the study, with exception of study-specified rescue medication.

Exclusion Criteria:

• Total knee replacement surgery tentatively scheduled within next 6 months.
• Palpable knee effusion.
• Significant pain outside the target knee, including significant hip, back, or contralateral knee pain.
• Any type of orthopedic and/or prosthetic device or any skin abnormalities on the target knee that would prevent evaluations of local tolerability.
• History of asthma, rheumatoid arthritis, chronic inflammatory disease (e.g., colitis), or fibromyalgia.
• History of gastrointestinal bleeding or peptic ulcer disease within the past 3 years.
• Have a positive urine drug test for illegal drug substances, non-prescribed controlled substances, or alcohol at screening.
• Acute or chronic illness that in the opinion of the investigator could compromise the integrity of study data or place the subject at risk by participating in the study.