1Clinical Epidemiology Unit, I.R.C.C.S. Orthopedic Institute Galeazzi, Milan, Italy
2Department of rehabilitation, Asl Biella, Italy
3Laboratory of Kinematics and Robotics. I.R.C.C.S. Fondazione Ospedale San Camillo, Venezia, Italy
4COF Lanzo Hospital, Lanzo d’Intelvi, Como, Italy
5Unit of Functional Recovery, Fondazione Centro San Raffaele del Monte Tabor, Milan, Italy
6APSS Tn, Villa Igea, Trento, Italy
7Department of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada; Arthritis Research Centre of Canada, Vancouver, British Columbia, Canada
8Rehabilitation Unit, University Hospital St. Orsola-Malpighi Polyclinic, Bologna, Italy
9Department of Epidemiology & Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
10Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
11Department of Biomedical Sciences for Health, University of Milan, Italy; Clinical Epidemiology Unit, I.R.C.C.S. Orthopedic Institute Galeazzi, Milan, Italy