About a year ago, I had a similar problem. The operation was already on the decline. Thanks to a suitable physiotherapist, rehabilitation and home exercise, everything started to improve after a while. I was in such a state that it was almost impossible to put on a shirt without help. Since I sought medical help late, it was not only the muscles in my shoulder, but also the pectoral and adjacent muscles. Today, my momentum is perhaps even better than that of a healthy hand.