1. Orthopaedic and Traumatological Department, S. Luigi Gonzaga Hospital of Orbassano, University of Turin, 72 Corso Lanza, Torino, 10131 Turin, Italy
2. Orthopaedic Department, Mauriziano Umberto I Hospital of Turin, University of Turin, 1 Via Magellano, 10128 Turin, Italy
3. Pelvic Surgery Department, Orthopaedic and Traumatological Hospital of Turin, University of Turin, 10 Regione Gonzole, Orbassano, 10043 Turin, Italy
4. Department of Radiology, Orthopaedic and Traumatological Hospital of Turin, University of Turin, 33 via Zuretti, 10100 Turin, Italy
5. Boston Medical Center, 850 Harrison Avenue, Boston, MA 02118, USA