We are currently seeking volunteers who experience pain daily, caused by arthritis of the knee. This is a study of a new investigational medication that may help to relieve the pain of Osteoarthritis of the Knee. Eligible participants will be determined based upon results from lab tests, pain questionnaires, and diagnostic procedures. Two out every three of the participants will receive the study medication and one out of every three will be receive a placebo. The medication is given by an intravenous (IV) infusion every 2 weeks for a total of 4 infusions. Participants must be willing to stop taking any other pain-relieving medications, prior to starting the study medication. They can, however, take up to 3000mg per day of rescue medication (Acetaminophen).