1. Department of Orthopedics and Traumatology, University Medical Center of the Johannes Gutenberg, University Mainz, 55131 Mainz, Germany
2. Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University, 60528 Frankfurt am Main, Germany
3. Department of Orthopedics (Friedrichsheim), Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, University Hospital Frankfurt, Goethe University, 60528 Frankfurt am Main, Germany
4. Department of Orthopedics, Tabea Hospital Hamburg, 22587 Hamburg, Germany
5. Medical Park St. Hubertus Klinik, 83707 Bad Wiessee, Germany