Even the best bred litters run the chance of carpal deformities.
Carpal Varus is simply the scientific term for the angle of the deformity.
Did your pup show signs of bow leggedness when you picked it up? And if so, why did you buy it?
If it didn't, what do you expect the breeder to do about it?
Considering most cases of bow legged, knuckling over, what ever you want to call it, correct themselves through easily managed structure, I still don't understand why you had the pup pts, but I imagine not an easy choice to make.