1. Department of Anesthesiology, Sint Maartenskliniek, Nijmegen, the Netherlands
2. Department of Orthopedics, Hôpital Ste-Marguerite, Marseille, France
3. Department of Anesthesiology, Kreiskrankenhaus, Langenau, Germany
4. Department of Orthopedics, Norrlands Universitetssjukhus, Umeå, Sweden
5. Department of Anesthesiology, Ziekenhuis Koningin Beatrix, Winterswijk, the Netherlands
6. Department of Orthopedics, Maasland Ziekenhuis, Sittard, the Netherlands
7. Department of Orthopedics, Ikazia Ziekenhuis, Rotterdam, the Netherlands
8. Department of Clinical Research, Ortho Biotech, Tilburg, the Netherlands