Yoga!

Exercise is key in any human.  You need to move around and get that heart a pumpin!  It also naturally floods your body with feel good endorphins, which is a great after surgery.  Here's a link for some yoga poses you can do without much risk of torquing yourself into a pretzel:

http://www.health.com/health/gallery/0,,20359611,00.html

Yoga is not only an excellent, non-invasive way to exercise...it is an excellent way to learn controlled breathing which can benefit you in so many ways including managing stress and blood pressure.  You don't need to pay for a class or worry about making a fool of yourself.  Do it at home and let your dog laugh at you!