Matteo Formica1, Luca Cavagnaro1, Carlo Formica2. 1. Clinica Ortopedica, University of Genoa, IRCCS A.O.U. San Martino Ist, Largo R. Benzi 10, 16132, Genova, Italy. 2. Clinica Ortopedica, University of Genoa, IRCCS A.O.U. San Martino Ist, Largo R. Benzi 10, 16132, Genova, Italy; CVCO, IRCCS Istituto Ortopedico Galeazzi, Via Riccardo Galeazzi 4, 20161, Milano, Italy.