75 patients with knee osteoarthritis were randomized to 4 different groups, including: exercise therapy without booster sessions, exercise therapy with booster sessions, exercise and manual therapy without booster sessions, and exercise and manual therapy with booster sessions. The purpose of this study was to determine whether the addition of manual therapy to exercise therapy would benefit patient-reported outcome measures of function and pain, and performance-based functional measure as compared to exercise therapy alone. Additionally, the study sought to evaluate whether booster sessions may improve outcomes at 1 year follow-up. Pariwise comparisons relative to the exercise therapy alone group as a reference demonstrated significantly greater reduction in scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) in the exercise therapy plus booster sessions group, and the exercise therapy plus manual therapy group, but not the group which received both booster sessions and manual therapy in addition to exercise therapy.