1. Department of Orthopaedic Surgery, Helios ENDO-Klinik Hamburg, Hamburg, Germany
2. Department of Orthopaedics and Traumatology, University of Rome Tor Vergata, “Policlinico Tor Vergata” Foundation, Rome, Italy
3. Department of Orthopaedic Surgery, Helios Klinikum Berlin-Buch, Berlin, Germany