re muzzle, Eva, don't rue its use. Many dogs are actually relieved when it goes on because it tells them, hey, you don't have to be in charge. When Hale Bopp was younger, his vet began using a muzzle with him for the vet's protection but after the first time, we began using it for Bopp's sense of well being. He liked not having to be in charge! We use another vet now and Hale Bopp has matured so we don't use it anymore.
Hale Bopp, when he was a pup, had so little leg muscle in back legs, and so big a chest, he actually would fall forward, would tip over when he tried to drink. Two ACL surgeries did the trick. I'm almost 100% sure the vet checked for knee movement (the drawer movement?) to determine if ACL was Homer's problem. But who knows, sometimes we jump over the obvious.
Re acupuncture, are you sure you got a good acupuncturist? Sounds as if s/he took no responsibility for Homer's pain -- but acupuncture shouldn't hurt. Try someone else? I would.
Good luck with your handsome boy, Carol