1. Department of Orthopaedic Surgery, Koenig-Ludwig-Haus, University of Wuerzburg, Brettreichstrasse 11, D-97074 Wuerzburg, Germany.
2. Department of Orthopaedic Surgery, University of Duesseldorf, Moorenstrasse 5, D-40225 Duesseldorf, Germany.
3. Department of Surgery, University of Wuerzburg, Josef Schneider Strasse 2, D-97080 Wuerzburg, Germany.
4. Klinik Vincentinum, Franziskanergasse 12, D-85152 Augsburg, Germany.