1. Mayo Clinic Alix School of Medicine, Mayo Clinic Rochester Minnesota USA
2. Department of Orthopaedics, Institute of Clinical Sciences, The Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
3. Division of Orthopaedics, Department of Surgery McMaster University Hamilton Ontario Canada
4. Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, The Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
5. IIa Clinica Ortopedica e Traumatologica, IRCCS Istituto Ortopedico Rizzoli Bologna Italy