1 Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
2 Trauma Department, Hannover Medical School (MHH), Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
3 Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA. ffu@upmc.edu.