My GSD, Sparky, is 9 years old. About a year ago, sparky began having a slight limp, and trouble bearing weight on his right front paw. I am a college student and sparky lives at home with my parents so I don’t get to see him all the time. My parents took sparky into several vets, all of whom can’t determine what the problem is. One vet recently told us there was a fracture on his toe in the lame leg, but after having a cast on for a month he still isn’t walking any better. His gait is off and sometimes he knuckles his right paw. Anyone have any advice???