1. AO Research Institute Davos, Clavadelerstrasse 8, Davos 7270, Switzerland
2. Guangdong Provincial Key Laboratory of Orthopedics and Traumatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, China
3. Institute for Biomechanics, ETH Zürich, Zürich 8093, Switzerland
4. CSEM, Swiss Center for Electronics and Microtechnology, Rue Jaquet-Droz 1, Neuchatel 2002, Switzerland