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 Orthopaedics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
4 Faculty of Health Care, Therapeutic Sciences, Niederrhein University of Applied Sciences, Krefeld, Germany.
5 Ergonomics and Biomedical Monitoring Laboratory, Wroclaw Medical University, Wroclaw, Poland.