If the puppy's joints are swollen, knobby, puffy, or crooked, he or she may have skeletal growth problems. Diets too high in protein, or diets without the proper calcium to phosphorus ratios commonly contribute to bone and joint growth abnormalities. Since the top brand, commercial puppy foods have been tested and proven, likely causes occur when one strays from the dog foods made for puppies. The breeder may be using adult food, a new or unusual brand, or too many supplements are being added to the diet. If the problems are identified early enough, diet correction is usually sufficient to normalize the joints within a few months.
More severe cases require corrective diet supplementation, leg splints and even corrective surgery.
It is best not to purchase puppies with joint problems. You can help your breeder by pointing out your observations. I have not heard of this in German shepherds. The vet put him on Phenobarbital, 30mg twice a day . He still has as many as 4 episodes in a 24 hr period.