German Shepard weak hind legs

I have a German Shepard who is more than 10 years old. Apart from being less active in the years, He has always been in good health until recently he has developed a weakness in both hindlegs and is very reluctant to walk at all. When he does walk his hind legs practically drag behind him. I love my friend very much and it is extremely heartbreaking for me to see him in this condition. Does anyone know what this may be or have a pet with similar condition who can suggest some treatments. I have visited many Vets and they believe that there is not much that can be done due to his old age.
Thankyou
Jane

I am not a vet but i do have loads of pet experience.

Your pet could be suffering from a form of arthritis. ...and I have heard that glucosamine can often help in these situations.

Good luck

ophelia