1. Department of Orthopaedic Surgery and Traumatology; Hospital General Universitario Gregorio Marañón; Madrid Spain
2. Department of Orthopaedic Surgery and Traumatology; Hospital Universitario Ramón y Cajal; Madrid Spain
3. Department of Physical Medicine and Rehabilitation; Hospital de Monforte de Lemos; Lugo Spain
4. Department of Medical; Grünenthal Pharma; S.A. Madrid Spain
5. Department of Design and Medical Writing; Medicxact; S.L. Alpedrete Spain