1. Department of Paediatric Orthopaedics and Adult Foot and Ankle Surgery, Orthopedic Hospital Speising, Vienna, Austria
2. Paediatric Orthopaedic and Traumatology Unit, Cesare Arrigo Children´s Hospital, Alessandria, Italy
3. Servicio de Cirugía Ortopédica y Traumatología Infantil, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
4. Orthopaedics and Traumatology Department,Hospital Sant Joan de Deu, Barcelona, Spain