1. Center of Experimental Rheumatology, Department of Rheumatology University Hospital Zurich, University of Zurich Zurich Switzerland
2. Department of Physical Medicine and Rheumatology Balgrist University Hospital, Balgrist Campus, University of Zurich Zurich Switzerland
3. Research Unit of Health Sciences and Technology University of Oulu Oulu Finland
4. AO Research Institute Davos Davos Switzerland
5. Department of Orthopedics Balgrist University Hospital Zurich Switzerland
6. Rehabilitation Services of South Karelia Social and Health Care District Lappeenranta Finland
7. Department of Orthopaedic Surgery University of California San Francisco San Francsisco California USA