Background: Service members are at an increased risk for development of arthritic conditions, such as OA of the knee, and therefore continued research into optimal intervention strategies is needed. Design: Comparative effectiveness parallel-group randomized controlled clinical trial. Methods: Subjects with a diagnosis of knee OA will be recruited through the primary care clinics across 3 military hospitals (MAMC, WHASC, and BAMC). Patients that consent and enroll will be randomized to receive usual care defined as the core management strategies defined by the DoD/VA Guidelines for the Management of Knee Osteoarthritis or this same usual care in addition to physical therapy. Patients will follow up at 6 weeks, 6 months, 1year and 2 years after enrollment. Summary: The results of this study will help inform and develop best practices for those with a diagnosis of Knee OA.