Exercise with injury

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I am 40 years old and having an extremly difficult time losing weight. Even after the lap band surgery i've been at a complete stand still for about 7 months. It is so frustrating!

I know I NEED to exercise for many reasons, but I recently tore the meniscus in my knee. It is a large tear with fluid around it. The Dr. said I Will need surgery in order for healing to begin and the pain to go away. I've been putting it off.

Does anyone have ANY exercise suggestions for me? I can do upper body and MAYBE some very mild leg work.

Any suggestions would be greatly appreciated!