1. Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA;
2. Department of Orthopaedics, University of Edinburgh, New Royal Infirmary, Little France, Edinburgh EH16 4SU, UK;
3. Arthro Nova Clinic, Rottach-Egern, Germany;
4. Orthopaedic University Hospital Heidelberg, Schlierbacher Landstr. 200a, 69118 Heidelberg, Germany