BEWARE of letting him exercise when he's medicated!!! The pain is there for a reason, to keep him from using this leg. Keep him crated as much as possible.

I would indeed seek a second opinion, and from an orthopedic specialist. If you are going to spend the money, you might as well do it at the top of the ladder.

Do some research in your area, find the BEST orthopedic vet, and go see them.

There are options that can give your puppy a very good quality of life. Some are more affordable than others, and some need to be done young, so time is of the essence.

Best of luck, keep us posted.