1. Ludwig Boltzmann Institute of Osteology, The Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, First Medical Department, Hanusch Hospital, Heinrich Collin Street 30, 1140 Vienna, Austria
2. Orthopaedic Hospital of Speising, Paediatric Department, Speisinger Street 109, 1130 Vienna, Austria