1. Department of Orthopaedics, Sint Maartenskliniek, Nijmegen - The Netherlands
2. Department of Orthopaedics, Rijnstate Ziekenhuis, Arnhem - The Netherlands
3. Department of Orthopaedics, Maxima Medisch Centrum, Veldhoven - The Netherlands
4. Department of Orthopaedics, Tergooi Ziekenhuizen, Blaricum - The Netherlands