Sami A Saku1, Rami Madanat2, Tatu J Mäkinen2. 1. Department of Orthopedics and Traumatology, University of Helsinki and Helsinki University Hospital, PL 900, Sairaalakatu 1, 00029 HUS, Vantaa, Finland. sami.saku@helsinki.fi. 2. Department of Orthopedics and Traumatology, University of Helsinki and Helsinki University Hospital, PL 900, Sairaalakatu 1, 00029 HUS, Vantaa, Finland.