Would you be comfortable later finding out that the surgeon who amputated your leg had an amputation fetish?

What if that surgeon's advice had been part of the decision process that lead to you deciding to go ahead with amputation?

Because it's a sign that he may have been amputating other people's limbs when not medically necessary.

Because there's at least a possibility that the surgeon recommended and performed amputations in order to satisfy his own fetishes rather than to do what's best for his patients. As a doctor, he is supposed to do what is best for the patient, not himself.

If it is verified that he has performed medically unwarranted amputations, that'd probably result in some kind of criminal charge due to the grave and permanent bodily harm involved. The loss of his medical license would be the least of his problems.

Joan's reported experience sounds like a pretty major issue to me.