Welcome to the board, muztangblondy.
I think if it were us, we'd be trying to find a good orthopedic specialist. Treatment seems to differ depending on which bones are involved and it can be tricky to manage effectively. I did find a site with a fair amount of information:
http://cal.vet.upenn.edu/projects/sa...1/41mast.htm#b If you scroll up and down, there is a lot of technical talk there, but it seems to indicate that young dogs treated as they grow tend to have better outcomes than those allowed to finish growing before treatment. Is that what your vet indicated?
A specialist would be able to give you a list of options and probably outcomes. If there are nonsurgical options available, they'd know of them!
for your dog! Keep us posted on her progress!