I showed GSD for several years, a few AKC Champions and obedience title holders. Got into the German imports and Schutzhund the last few years. Had the Southeastern Siegerin in 2011. She passed away last year and never had any health issues until the end.
HD is a problem. a good breeder should be able to show you several generations of HD and elbow certification. Elbow dysplasia is pretty much as common as HD and just as devastating.
over 40 years, I only had a couple with HD, but I absolutely would not touch anything that wasn't several generations HD/ED free, and it can still crop up.
personally, I will never own another American/Can. show line. there are other issues. I prefer the German/Czech working line, but the old saying is "puppies are a crap shoot" is very true.
a good breeder will also offer a replacement health guarantee , but that doesn't help a lot after the dog has your heart.