1. The Arthritis Foundation, Atlanta, GA, USA
2. Department of Orthopaedic Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands
3. Department of Orthopedic Surgery, Boston Children’s Hospital, Boston, MA, USA
4. Department of Medicine and Rheumatology, University of California, Davis Medical Center, Sacramento, CA, USA
5. Division of Rheumatology, Allergy, and Immunology, Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
6. Department of General Practice, Erasmus University Medical Center Rotterdam, Rotterdam, the Netherlands
7. Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA
8. Hospital for Special Surgery, New York City, NY, USA