1. Arimatias Raitio Department of Pediatric SurgeryUniversity of Turku and Turku University Hospital Turku Finland
2. Turku University Hospital, Savitehtaankatu 5, 20520 Turku, Finland
3. Department of Orthopedics and Traumatology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
4. Department of Pediatric Surgery and Orthopedics, Clinical Medicine Research Unit, Oulu University Hospital, University of Oulu, Oulu, Finland
5. Department of Pediatric Surgery, Orthopaedics and Traumatology, University of Turku and Turku University Hospital, Turku, Finland