I've had lots of practice with getting out of bed without using my upper body muscles much. Here's my recommendation (which may not work for everyone):
When in the hospital, gradually work towards laying on a flat(ish) bed. Each night I would lower the back a little more until I was sleeping on it in its flat position (but still had pillows to prop me up). I hate sleeping on my back, which is why I worked towards this as quickly as I could. While in the hospital I used the bed to lower and raise my head to get in/out of it. However, at some point I began practicing leaving it flat and getting myself up and down without the help (sometimes DH would help lower me down gently). To get out I did what others have mentioned: put one leg over the edge then roll out. I recommend holding a pillow to your chest while you do that. It will help you not use those muscles for getting up.
By the time I got home (I was in the hospital 9 days, getting my coumadin regulated) it was not a problem transitioning to my own bed. Of course, I'd also had practice before (I've had a total of 16 surgeries at this point), and have never slept in a recliner. Mostly because (like I said before) I hate sleeping on my back. Even to this day I sleep on my side, hugging a pillow to protect my chest!
Good luck! You might try practicing getting in/out of bed now and see if you think you can do it.