What happens to the pups prior to growth plate closure has a big impact on the development of hip dysplasia. All puppies are BORN with perfect hips but how they develop as the cartilage changes to bone and as they grow can have a big impact. Most of the factors can be controlled by breeders and owners to help increase the proper formation of the joints.
http://www.louisdonald.com/blog/the-10-most-important-things-to-know-about-canine-hip-dysplasia
Raising a Genius Puppy 