1. Department of Orthopedics, Balgrist; University of Zurich; Lengghalde 5 Zurich 8008 Switzerland
2. Institute for Biomechanics; ETH Zurich; Zurich Switzerland
3. Swiss Federal Laboratories for Materials Science and Technology; Zurich Switzerland
4. Oxford University Hospitals, NHS Trust; Nuffield Orthopaedic Centre; Oxford United Kingdom