1. Department for Shoulder and Elbow Surgery, Center for Musculoskeletal Surgery, Charité Universitaetsmedizin Berlin, 10117 Berlin, Germany
2. Institute of Biometry and Clinical Epidemiology, Charité Universitaetsmedizin Berlin, 10117 Berlin, Germany
3. Department of Shoulder and Elbow Surgery, Schulthess Clinic Zurich, 8008 Zurich, Switzerland