Participants will be randomly assigned to one of two groups. The first group will participate in a standard rehabilitation program of traditional exercise therapy for knee OA. The second group will participate in a standard rehabilitation program supplemented with a knee stability program. Study visits will occur at study entry, 2 months, 6 months, and 1 year. At each study visit, changes in pain, physical function, and biomechanical factors will be assessed. This study will last for one year.