The mistake was identified during a routine bandage change and the patient was told he would have to have his other leg amputated as well.
In court, the surgeon said there had been a flaw in the chain of command in the operating theatre.
When asked why she had marked the right leg and not the left, she said: “I just don’t know”.
Since the incident, she has moved to another clinic. Half of her fine has been suspended.
Cases like these are rare but there have been similar incidents in the past.