I am assuming they are planning on doing a FHO (femoral head ostomy). I had a pup that had this surgery. He had lived in pain for many years when he came to me and limped....his muscle had also atrophied as you describe. He had the surgery and it took a while, but he did regain full use of the leg and also developed the muscle.
I also had another with a bit different surgery, but with extreme muscle atrophy...and the improvement took a few months, but it is amazing how they do recover.
Their muscles, like ours, atrophy if not being used; but with exercise they do come back.
Good luck and keep us posted on this!
