1 *Department of Medical Psychology and Sociology, Ruhr-University of Bochum, Germany †Department of Orthopaedics, University Hospital of Gothenburg, Sweden ‡Division of Physiotherapy, Department of Health & Rehabilitation Sciences, University of Cape Town, South Africa §School of Health, Care and Social Welfare Mälardalen University, Västerås, Sweden ∥Mill Park, Port Elizabeth, South Africa ¶Department of Rehabilitation Medicine, Maastricht University, Maastricht NL #Centre for Pain Medicine, Swiss Paraplegic-Centre, Nottwil, Switzerland **Department of Physical Therapy, School of Health Professions, University of Texas Health Science Center at San Antonio, TX.