1. Department of Orthopaedics, Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
2. Department of Orthopaedics and Sports Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
3. Institute of Musculoskeletal Medicine, Medical Faculty, Westphalian Wilhelm University, Münster, Germany
4. MVZ-Zentrum für Histologie, Zytologie und Molekulare Diagnostik GmbH, Trier, Germany
5. Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany