1. Department of Orthopaedic and Trauma Surgery, Campus Biomedico, University of Rome, Via Alvaro del Portillo, 200 00100 Rome, Italy.
2. Department of Neurosurgery, Catholic University School of Medicine, Largo Agostino Gemelli, 8. 00168, Rome, Italy.
3. Centre for Sports and Exercise Medicine, Barts and The London School of Medicine and Dentistry, Mile End Hospital, 275 Bancroft Road, London E1 4DG, UK.