shoulder joint replacement
I had total shoulder joint replacement (twice, thanks to an idiot surgeon who messed up the first try, but that's not my point) and after five years do not have (and will never have) full motion or strength. Nevertheless, water exercise has helped me recover further than the second surgeon believed possible. My physical therapist gave me a short (10 minutes or so) set of resistance exercises using hand paddles in the water to develop and maintain strength. I do these three times a week in addition to five to seven days per week of doing ti drills and "swimming" as best I can (think bird with broken wing). As you recover from your surgery you might ask your physical therapist to recommend something similar, or maybe consult with a physical therapist who specializes in water exercise (I worked with such a person who was extremely helpful). And hang in there! It's awful but will get better.