1. Department of Orthopaedic Surgery, Centre for Orthopaedic Research Alkmaar (CORAL), Alkmaar - The Netherlands
2. University Hospitals Leuven, Pellenberg site, Department of Orthopaedic Surgery, Pellenberg - Belgium
3. Research Institute MOVE, Department of Human Movement Sciences, VU University Amsterdam, Amsterdam - The Netherlands
4. Helios Klinikum Duisburg, Department of Orthopaedic Surgery and Traumatology, Duisburg - Germany