Hey Wrinkles, I had adhesions after rotator cuff surgery and got a general and was fully ranged and had intensive PT and my shoulder is back almost 100%. If you can somehow manage it that may be the best way to go.
Also you might find the shorter scale of an octave mandolin a little easier on you than the bouzouki.
What kind of bouzouki do you play? I'm thinking about having one made. Best of luck, vl