1. Department of Orthopedic Surgery, Medical University of Vienna, Vienna, Austria
2. Department of Internal Medicine III, Division of Rheumatology, Medical University of Vienna, Vienna, Austria
3. Department of Radiology and Nuclear medicine, Medical University of Vienna, Vienna, Austria
4. Department of Internal Medicine III, Division of Rheumatology, Medical University of Vienna, Waehringer Guertel 18–20, Vienna, 1090, Austria