EB, please excuse me but I can't control myself from another comment. Since you said "replaced" about your shoulder I guess it may have benn luxated or operated upon or will be operated. In such cases it is reasonable that canoeing and kayaking ( causing particular stress on the shoulder joint) is troublesome and rowing a little less so, but theoretically hazardous as well. Sailing with all the usual demands of fitness would scare myself off in greater degreee...but well, there are one-armed sailors who get along...
But again...not playing concertina?? My arm was paretic except some of the fingers and playing worked more or less. The possible *stress* on the shoulder joint may be completely eliminated.BUT playing the concertina in the normal way and maybe using energetic push-pull (Anglo-wise firstly) there are obvious risks for overuse troubles from the shoulder...BUT they ought to be avoidable.Why not speak to your doctor( with my respectful regards..) again. Maybe something can be worked out.