1. Department of Digestive Surgery, Turku University Hospital, Kiinamyllynkatu 4-8, Turku, 20520, Finland
2. Department of Digestive Surgery, Turku University Hospital, University of Turku, Turku, Finland
3. Department of Orthopaedics, Satakunta Central Hospital, Pori, Finland and University of Turku, Turku, Finland
4. Biostatistics, Department of Clinical Medicine, University of Turku, Turku, Finland