Sorry to hear this cm11. I do not have a full answer for you however I can make a suggestion about staying in decent shape. Back in high school, my coach had a "hand cycle" exercise machine. It’s a goofy looking machine that looks like a bike machine but you use your hands instead of your feet/legs. Like a bike machine you could increase the resistance for greater difficulty. The machine shot up heart rates and increased overall arm endurance. If you can find one in your local gym or in a campus training center you could probably keep a good level of cardio endurance. Also look into seated rowing machines (keeping your legs planted on the ground however). Take it with a grain of salt though, this won’t help anything in your legs. The loss of muscle mass and muscle endurance in your legs will take its toll. These forms of exercise will only keep your heart healthy and strong. Good luck in recovery.
P.S. If you can get a Physical Therapist to help, you won't regret it. Their
Workouts will have you thinking they are sadists but the benefit in recovery is phenomenal.