Polar Bear, I wish you and your dog the best.
I have a GSD and despite getting him from a reputable breeder, it seems as though he has a mild case of hip dysplasia. I haven't yet confirmed this with my vet because I'd rather not put him under any time soon (he's been under way too many times already for various health issues). Until then, I have been doing what mummumum suggested, and have been using glucosamine chondroitin supplements. Personally, I use Cosequin DS. It's not cheap, but it really seems like it's the best one available (save for Dasuquin, which is from the same company but is even more expensive and is available through prescription only). I don't really notice a HUGE difference, but my baby isn't complaining and it can only help.