COVID-19 strategy in organizing and planning orthopedic surgery in a major orthopedic referral center in an area of Italy severely affected by the pandemic: experience of the Department of Orthopedics, University of Padova - Ruggieri, P; Trovarelli, G; Angelini, A; Pala, E; Berizzi, A; Donato, D (J Orthop Surg Res, 2020)