- self reported knee pain (defined as medial compartment knee pain at least 1 day per week during each of the 6 weeks prior to participation) and at least 3 of the following 6 clinical indicators: Age>50 years; morning stiffness<30 minutes duration; crepitus on active motion; tenderness of the bony margins of the knee joint; bony enlargement at the knee; and lack of palpable warmth of the synovium