[warfangle]

Pilates could be very useful. Most of it is very low impact strength training - instead of holding up your body weight, you're straining against springs, for example. There are a lot of exercises that don't focus on the arms because Pilates focuses on very discrete muscle groups for each exercise.

I wouldn't start with group classes, though: talk with your physical therapist (are you doing PT to help the recovery?) about appropriate exercises, and maybe sign up for a few introductory private pilates classes. Be sure to inform the instructor about the limitations you have.