It's probably osteoarthritis, but you should have your doctor take a look. You may need some X-rays to be sure.

Does the knee swell, or get red and inflamed? I hope not. If it does, it could be rheumatoid, but from what you say it doesn't sound like it. It sounds more like the osteo kind. You really shouldn't be crossing your legs either. That's a bad habit that we've all got. Crossing the legs can effect the blood flow to the lower legs. We really shouldn't be doing it at all! It's a BAD habit especially as we get older.

Talk to your doctor about your knee. Let us know what happens, ok? I wish you the very best. God bless & please take care. Hugs, Lee