1. Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Rome, Italy
2. Research Unit of Orthopaedic and Trauma Surgery, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Rome, Italy
3. Facility of Epidemiology and Biostatistics, Fondazione Policlinico Univeristario A. Gemelli, IRCCS, 00168 Rome, Italy
4. Department of Medicine, University of Navarra, 31008 Pamplona, Spain