1. Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University, 60590 Frankfurt am Main, Germany
2. Stavros Niarchos Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, NY 10021, USA
3. Charité—Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Center for Musculoskeletal Surgery, 10117 Berlin, Germany
4. Spine Care Institute, Hospital for Special Surgery, New York, NY 10021, USA
5. Department of Orthopaedic Surgery, University of Ulm, 89075 Ulm, Germany