- Trial participants must meet American College of Rheumatology (ACR) criteria for osteoarthritis with knee pain, aching or stiffness on most of the past 30 days and evidence on radiograph of a definite osteophyte. In addition, because the researchers are interested in recruiting persons with medial knee osteoarthritis, participants will need to have evidence of disease in this compartment on their radiographs, and not have lateral compartment or patellofemoral compartment disease. Medial disease is based on definitions used in the researcher's previous publications as definite radiographic OA + at least grade 1 medial narrowing (0-3 scale) using an atlas from the Osteoarthritis Research Society International.