Sorry, i do not have any suggestion for the surgery but i do have something to say.
7 months is still a puppy, and everything you are describing is a puppy being puppy, i also have a high drive pup and ya i know they can be handful sometimes. Every dog has it's baggage of some sort, if you had adopted i am sure you would find some baggage in them too, the only difference is the puppy is small in size and less intimidating that the adult one. Guess which one is easier to teach some behavior?
Second thing, the pup will want to run, play regardless of the stage they are in, we are the ones who have to think about the time they can run around, we have to have the bigger picture. If week on couch can give him few years mobility then why not?
Your pup is still in a puppy stage, get him to a obedience class if not yet done, get him to a behaviorist if obedience is not working and see she will amaze you. I have been around Tibetian Mastiff since my childhood and believe me they are can be really gentle when they are adult, if a TM can then a GSD will be more than you expected.
Help her impress you, get her into training, get her something to do, try NILF, try 2 balls fetch, try mind games...try everything you can think of. It's never too late.
Robean Gyalchen Lamakhor.
Tyson GSD 09 JUNE 2013
Rusty BOXER 12 Jan 2009 to 25 Oct 2012