To be fair what the vet said was that being as Phoebe only has one back leg it is important to keep her good back leg as healthy as possible. I did have a pomeranian who had the luxating patella in both his hind legs. He was able to stretch the legs out by balancing on the other leg and pop them back in place on his own but as Phoebe doesn't have the use on her left hind leg she can't balance on it in order to stretch the other out. So far she is healthy and doesn't let being a three legged dog stop her or slow her down. She not only keeps up with my sisters 4 pugs but runs circles around them. She is the quintessential pesty lil sister (or cousin in this case).
