Wrong site surgery is a type of medical malpractice that may be more common than you might think. Wrong site surgery occurs when a doctor or surgeon performs an operation on the wrong part of your body – or on the wrong patient altogether. The most common form of wrong site surgery takes place when a surgeon operates on the wrong side of the body, such as a knee replacement on the right knee instead of the left knee. Wrong site surgery is almost always the fault of the doctor or hospital. Studies have shown that wrong site surgery medical mistakes can easily be prevented with medical checklists and careful, thoughtful hospital staff.