Christoph-E Heyde1
, Johannes K Fakler1
, Erik Hasenboehler2
, Philip F Stahel2
, Thilo John1
, Yohan Robinson3
, Sven K Tschoeke1
and Ralph Kayser1 
1
Department of Trauma, Orthopedics, and Reconstructive Surgery, Charité, University Medical Center, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany
2
Department of Orthopedic Surgery, Denver Health Medical Center, University of Colorado, School of Medicine, 777 Bannock St, Denver, CO 80204, USA
3
Department of Orthopaedics, Academic Hospital, Uppsala University, 751 52 Uppsala, Sweden