1. Center of Orthopaedics and Traumatology, University Hospital Brandenburg/Havel Brandenburg Medical School Theodor Fontane Brandenburg a.d.H. Germany
2. Faculty of Health Sciences Brandenburg Brandenburg Medical School Theodor Fontane Brandenburg a.d.H. Germany
3. Department of Physical Therapy Faculty of Medicine University of Iceland Reykjavík Iceland
4. Department of Orthopaedics, Sahlgrenska University Hospital Sahlgrenska Academy Gothenburg University Gothenburg Sweden
5. Basel University Switzerland
6. Department of Orthopaedic Surgery and Traumatology Kantonsspital Baselland Bruderholz Switzerland
7. Norton Orthopedic Institute Louisville Kentucky USA
8. Department of Orthopaedic Surgery University of Louisville Kentucky USA