Mare with questionable breeding history

Question
I recently acquired a very well bred mare to cross with my appendix stallion who is extremely correct and throws very correct foals (almost all his babies have had his conformation - though I have picked the mares very carefully to cross with him).  She is well put together herself, however she has a somewhat club foot (her right leg seems to turn in and she paddles slightly).  I have bred many horses and dealt with all types of breeding, however I have not specifically dealt with this conformation defect.  The people I got her from stated the poor conformation was due to neglect as a young horse and not receiving proper farrier care.  I understand that this can cause defects.  It does not seem to bother her, and she is sound on the leg, however I am concerned about the possibility of passing this defect on.  I was unable to evaluate other horses with similar breeding as she was the only foal out of her dam and sire, both of which are now deceased.  Also, she is a maiden, so she has no reproductive history to base things on.  I have had x-rays taken of the leg and my vet stated it is impossible to tell whether it was a genetic defect or due to improper shoeing.  All he knows is that is definitely is not due to injury.  He stated he was unsure whether the defect would be passed on and told me I really wouldn't know until I bred her.  However, can you tell me the likelihood of passing this on.  Obviously this is a concern for me as I want to only produce correct foals if possible, though I purchased the mare as a breeding prospect she currently functions as a babysitter to the weanlings.

Answer
Hi Amanda,

               As I am sure you are aware, Clubfoot is a deformity of the foot which occurs at birth or during childhood. About 50% of mares that have a club foot, throw off a foal with one. I would not breed this mare, as the chance of her throwing off a foal with a club foot is 60% or more. Since, you do not if the condition is congenital or from neglect then you should keep the mare as a baby sitter.

Lisa