1. Department of Orthopedics (Friedrichsheim), University Hospital, Goethe University Frankfurt, Frankfurt, Germany
2. Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
3. Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Department of Orthopedics (Friedrichsheim), University Hospital, Goethe University Frankfurt, Frankfurt, Germany
4. Center for Musculoskeletal Surgery, Charité - University Hospital Berlin, Berlin, Germany