1. Department of Orthopaedic Surgery, Herlev Hospital, University of Copenhagen, Herlev, Denmark;
2. Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus, Denmark;
3. Department of Orthopaedic Surgery, Aalborg University Hospital, Aalborg, Denmark;
4. Department of Orthopaedic Surgery, Zealand University Hospital, University of Copenhagen, Køge, Denmark