1. Department of Orthopaedics and Trauma Surgery, University Hospital Essen, Hufelandstraße 55, 45147 Essen, Germany
2. Institute of Pharmacology and Toxicology, Witten/Herdecke University, Alfred-Herrhausen-Straße 50, 58455 Witten, Germany
3. Department of Joint Surgery, Helios ENDO-Klinik Hamburg, Holstenstraße 2, 22767 Hamburg, Germany
4. Department of Orthopaedics and Trauma Surgery, St. Barbara Hospital Gladbeck, Barbarastraße 1, 45964 Gladbeck, Germany