1. Department of Orthopedic and Traumatology, Technical University Munich, Klinikum Rechts der Isar, Germany
2. Department of Joint Arthroplasty and Clinical Science, Mare Clinic, Kiel, Germany
3. Institute of Sportsmedicine, Frankfurt am Main, Germany
4. IDV Data Analyses and Study Planning, Biometrics in Medicine, Gauting, Germany
5. Department of Orthopedics, Ludwig Maximilian University, Munich, Germany
6. Weil Foot and Ankle Institute, Des Plaines, Illinois
7. University Schleswig Holstein, Campus Lübeck, Lübeck, Germany
8. Department of Podiatry, The Permanente Medical Group Inc, Union City, California
9. Orthopaedic Foot and Ankle Center, Manhattan Beach, California
10. Department of Orthopedics, University Rostock, Rostock, Germany