1 Department of Orthopaedics, Sahlgrenska University Hospital, Molndal, Sweden. jon.karlsson@telia.com.
2 Department of Orthopaedic and Traumatology, City Hospital Brandenburg, Hochstrasse 29, 14770, Havel, Brandenburg, Germany. roland.becker@kssta.org.
3 Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland, Bruderholz, Switzerland. Michael.Hirschmann@unibas.ch.
4 Orthopaedic Surgery and Bioengineering, UPMC Center for Sports Medicine, University of Pittsburgh, 3200 South Water Street, Pittsburgh, PA, 15203, USA. musahlv@upmc.edu.