1 Institute of Medical Biometry and Statistics, Medical Faculty & Medical Center, University of Freiburg, Freiburg, Germany.
2 Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland.
3 Division of Infectious Disease, Department of Internal Medicine I, Tübingen University Hospital, Tübingen, Germany. primrose.beryl@med.uni-tuebingen.de.