Are you able to sit? If so, and you really want to exercise, I encourage you to visit
www.chairdancing.com These folks have audiotapes, VHS, or DVDs that allow you to do yoga, muscle toning, and aerobics while seated in a chair. They are very reasonably priced (and no I don't have anything to do with them financially whatsoever!).
I have a hard time getting up and down from a yoga mat and my local TV station did a health spot on chair yoga- I was interested and found these folks through a google search. I was so happy with the yoga tape that I have purchased several aerobics and the toning DVDs.
They look easy, but you can get a good workout- while sitting down!
good luck
sandy