Happy has the right idea.
Perhaps trying to take her mind off it would be a good idea. For example:
I am sorry to hear about your surgery. But at least your vaginas still working.
This accomplishes several things- it acknowledges her surgery, let's her knoe you care, and also says even though her face will be alll swollen and bloody your willing to get freaky with her.
I think Hallmark has this as a card!