1. Department of Rheumatology, Sint Maartenskliniek, Nijmegen, The Netherlands
2. Division of Rheumatology, Geffen School of Medicine UCLA, Los Angeles, CA, USA
3. Department of Orthopedics, Sint Maartenskliniek, Nijmegen, The Netherlands
4. Department of Rheumatology, Radboud University Medical Centre, Nijmegen, The Netherlands
5. Department of Rheumatology and Clinical Immunology, University Medical Centre Utrecht, Utrecht, The Netherlands