Our 4 month old pup has pulled up lame after exercise. Our vet took Xrays, which indicated no problems, however orthopaedic tests have indicated the onset of Elbow Dysplasia

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This has opened up a can of worms - our vet wants to let Helius behave normally (monitoring exercise with caution) and without pain killers that will mask his condition; we will then re-test in a month to look for any bony changes and operate in a month if required - he suggests surgery is the best and most modern way to go in order to give Helius the best quality of life.
Our breeder thinks confining him to a crate for 2 weeks and using anti inflams is the way to go. Helius' parents have elbow ratings of 0 for the mother and 1 for the father, which the breeder thinks provided evidence that surgery will not be required.
Our puppy is 20kg at 17 weeks, but is not fat by any means. You can clearly see his rear ribs and palpate the others. He has large (6cm / 2+ inch) paws, a large head and bulky shoulders. The breeder's feeling is that he is simply growing too fast and needs to be put on a modified diet to slow down growth and give his joints a chance to harden.
What should we do (of course all posts will be taken as advice only)?
New school - operate if the xrays show some bony change and go with the current vetinary trends, or go with the breeder (
Old School)and hope that it goes away with careful nurturing and monitoring. Our risk is that at after 1 year, surgery is pointless, but pre one year, is thought to be beneficial

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Any and all thoughts on this issue are appreciated.