Heart problems are big in this breed.
I would never buy a puppy from dogs that have not had their hearts certified.
The standard for Rottweilers is the same... from Germany, Italy, Canada or USA....the only difference will be the tails.
What you probably had was a poorly bred Rottweiler...I would not be blaming the joint problems on being American bred.
Take a look at the "stickies" on the Breeding forum..learn what a good breeder is.
You really would not be able to tell a well bred Rottweiler that was from Germany or born in North America.
If you are just wanting a house pet (I'm surprised the breeder in Germany would sell you a puppy
)....then look into adopting a rescue dog. There are so many beautiful dogs sitting in shelters or in a rescue that need homes.
Gina