1 Department of Orthopaedics, Sahlgrenska Academy, University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Gothenburg, 431 80, Sweden. jon.karlsson@vgregion.se.
2 Department of Orthopedics and Traumatology, Centre of Joint Replacement, Hospital Brandenburg, Medical School "Theodor Fontane", Hochstrasse 2, 14770, Brandenburg, Germany.
3 Department of Orthopaedic Surgery, Center for Sports Medicine, UPMC Rooney, Pittsburgh Medical Center, 3200 S Water Street, Pittsburgh, PA, 15203, USA.
4 Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland (Bruderholz Liestal, Laufen), 4101, Bruderholz, Switzerland.