G Dirkx1, P Caekebeke1, J Duerinckx2. 1. Department of Orthopedic Surgery and Traumatology, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600 Genk, Belgium. 2. Department of Orthopedic Surgery and Traumatology, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600 Genk, Belgium. Electronic address: joris.duerinckx@zol.be.