I would go to my vet and ask for a referral to an orthopaedic specialist in order to get a correct diagnosis at this early stage. Is the puppy insured, as it can be costly.
ditto above. I have a bitch who is now nearly five years old, who suffered a rupture of the anterior cruciate at 18 months of age, I self referred to get her appropriate treatment, after the vet I was with, seemed willing to allow such an injury to heal by itself. Good luck, hope all is ok.
Thank you so much for your advice very helpful. I actually meant to say chiropractor and not osteopath as it is not diagnosed yet I am only guessing and I didnt know who would do the best diagnosis.