1. Orthopaedic Hospital, University Lausanne, Av. Pierre-Decker 4, CH-1005 Lausanne, Switzerland.
2. Department of Orthopaedic Surgery, University of Zurich, Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland.
3. Schulthess Clinic, Lengghalde 2, CH-8008 Zurich, Switzerland.