Could Sitting Cross Legged Cause Swelling, Pain And Pulling Sensation In Knee?

I sat cross legged while meditating. I am an overweight woman, but overweight by only 20 pounds, and I'm in fairly good shape. After standing up, my I felt a pulling sensation in the back of my right knee, that progressed into a great deal of swelling and pain. Why would sitting cross legged have this effect?