Could Swelling And Stiffness In Knee Be Due To Torn Meniscus?

I have had a torn meniscus in my right knee about a three years ago.I did not treat it...this past week my right knee feels a little swollen and stiff and hurts on the right side. Also there s a clicking that I can feel in the joint. Other relevant facts are I am on Coumadin because I had a blood clot was in my leg and one in my lungs about 10 years ago due to a Latin factor five. My blood levels remain consistent over these years as I have been check monthly for Coumadin. Which one of these does it sound like?