1. Clinical Orthopaedic Researc Hvidovre (CORH), Department of Orthopaedics, Copenhagen University Hospital Hvidovre, Copenhagen;
2. Department of Orthopaedics, Holbaek Sygehus, Holbaek;
3. Department of Orthopaedics, Copenhagen University Hospital Bispebjerg, Copenhagen;
4. Clinical Research Centre, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark