1. Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
2. Department of Orthopaedic Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
3. Department of Radiology, Division of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, Yawkey 6E, 55 Fruit St, Boston, MA 02114.