The standardized questionnaires for the long-term follow-up had initially been mailed annually to the patients starting from 2 years after surgery. In 2010, the routine was changed to sending out questionnaires after 2, 5 and 10 years. A cover letter explained the purpose and asked that the questionnaire be completed at home, by the patient, a next-of-kin or caretaker. A reminder was sent to patients who did not reply to the first letter.