Why does Mrs. Pumphrey think the dog's recovery is "a triumph of surgery?

When Tricki was admitted to Mr. Herriot, its condition was so critical that it could not even walk properly. Mr. Herriot had told her that he would need a surgery to be fine. When Mrs Pumphrey got Tricki back he was absolutely fit and fine. This made Mrs Pumphrey believe that the dog’s recovery was “a triumph of surgery”.