I'm thinking that if you had some sort of harness to support her hind quarters and lift her rear end up you might be able to assist her to and from the out doors in order to use the potty.
I found this:
Harnesses and Slings Help Dogs Walk
As far as the can food thing if it were I would not feed her can food reason being it has a tendency to loosen their stool. If you are giving her access to potty inside during her recovery. . . it will get messy.
Also be sure she has a really really soft bed or blankets to lay on. So that she is as comfortable as possible.