1. AO Research Institute Davos; Clavadelerstrasse 8; CH-7270 Davos Platz Switzerland
2. Department of Trauma, Hand and Reconstructive Surgery; University Hospital Jena; Germany
3. Cantonal Hospital Baselland; Liestal; Switzerland
4. University of Basel; Basel; Switzerland
5. Department of Foot and Ankle Surgery; Catholic Hospital Mainz; Germany
6. Department of Anatomy and Cell Biology; Martin-Luther-University Halle-Wittenberg; Faculty of Medicine Halle (Saale) Germany