[Carthego delenda est]

“German shepherds are prone to hip dysplasia, too.”

I wonder if the shortened spine might actually help with dysplasia? My thinking is that with a shorter spine, perhaps the little guys hips don’t have to support as much weight, less body.

[Aliska]

I did some skimming. It is hereditary but nutrition and other factors come into play. Your theory is borne out "Most vets argue that extra weight on your dog’s frame can lead to stress and pressure on his joints, especially his hip joints."

They are prone to arthritis, too.

http://www.wikihow.com/Prevent-Hip-Dysplasia-in-Dogs

At least they know some preventive measures and good diagnosis, didn't read far enough to find out much about treatment, assume the longer it's let go or not diagnosed, the harder to treat.