1. Orthopedics and Traumatology, St Marien-Hospital Mülheim an der
Ruhr, Mülheim, Germany
2. Orthopedics and Traumatology, University of Duisburg-Essen Faculty of
Medicine, Essen, Germany
3. Orthopedics and Traumatology, katholische Kliniken Philippusstift
Essen, Essen, Germany