1. Orthopaedic Research Laboratory; Aarhus University Hospital; Denmark
2. Elective Surgery Center; Silkeborg Regional Hospital; Silkeborg Denmark
3. Department of Orthopaedic Surgery; Regional Hospital Viborg; Viborg Denmark
4. University of Minnesota Department of Orthopaedic Surgery; Minneapolis Medical Research Foundation; Minneapolis Minnesota
5. Department of Orthopaedic Surgery; Aarhus University Hospital; Aarhus Denmark