You don't know that. Maybe she was, maybe she wasn't. That's why they have trials, supposedly, to get at the truth.
I cannot imagine that she was not informed. I was informed in a consultation, and in a written pamphlet. I was asked by personnel at the hospital about it. Its a very very well known risk.
Having surgery is a choice. A choice between leaving things as they are, and that of taking the RISK to change them. Its a risk. Statistically speaking, for some it does not pay off. Thats harsh, but its also reality. Now if it was an emergency procedure, that is altogether different. At that point, its about life or death. This does not sound like that sort of situation. She made and informed choice. If she was NOT informed, then she has a case. I just strongly doubt that is the case.