Thank you Dr., My left knee has been swollen and unable to bend to the flexability that I am used to. granted this past year my knees have started to hurt quite a bit, I figure due to arthritus, but this one locked up one day, it swelled up and was very very painful if I moved it at all. That lasted a few days and now it isn t near as tender, but it s swollen on the outside and on the back of the knee. I currently don t have health insurance and can t seek treatment. Do you have any ideas as to what is causing this?