It depends on the age of the dog if that will help. I think that was probably a puppy comment as this is commonly seen in pups as a nutritional or growth issue.
You may be seeing the results of the early diet on your dog, a hereditary issue with the joint, or just an injury to soft tissue or the joint area.
I would suspect an x-ray and an exam by an ortho vet might help.
You can check here on the surgeons list to see if there is an ortho person near you
http://www.acvs.org/AnimalOwners/DiplomateDirectory/
With his age it may take surgery to repair what is going on with him.
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