If you join, you might get hand and knee X-rays and a knee MRI and ultrasound. You might wear activity monitors, take part in tests on movement, exercise and pain and fill out questionnaires about your health.

You might be a great fit if you're 45+ years of age, have not had knee replacement surgery, and do not have rheumatoid arthritis or other inflammatory arthritis conditions. If you qualify, you could receive up to $250 in compensation for your time.

To learn more about participating, call (205) 975-0988.