1. Erasmus MC , University Medical Center Rotterdam, Department of Public Health, Rotterdam, PO Box 2040, 3000 CA Rotterdam , The Netherlands
2. Department of Surgery , Northwest Clinics Alkmaar, P.O Box 501, 1800 AM Alkmaar , The Netherlands
3. Trauma Research Unit Department of Surgery , Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam , The Netherlands
4. Geriatrics Section , Department of Internal Medicine, Amsterdam UMC location AMC, PO Box 22660, 1100 DD Amsterdam , The Netherlands
5. Department of Public Health and Primary Care , Leiden University Medical Center, Hippocratespad 21, PO Box 9600, 2300 RC Leiden , The Netherlands
6. Department of Orthopaedic Surgery , Elisabeth-TweeSteden Ziekenhuis, PO Box 90151, 5000 LC Tilburg , The Netherlands
7. Department of Surgery , Rode Kruis Ziekenhuis, PO Box 1074, 1940 EB Beverwijk, The Netherlands
8. Department of Orthopaedic Surgery , Dijklander Ziekenhuis, PO Box 600, 1620 AR Hoorn , The Netherlands
9. Department Trauma TopCare , Elisabeth-TweeSteden Ziekenhuis, PO Box 90151, 5000 LC Tilburg , The Netherlands
10. Department of Orthopaedic Surgery , Isala, PO Box 10400, 8000 GK Zwolle , The Netherlands