1. Department of Orthopaedics; Leiden University Medical Centre; Leiden the Netherlands
2. Department of Radiology; Leiden University Medical Centre; Leiden the Netherlands
3. VU University Medical Centre; Department of Rehabilitation Medicine; Amsterdam the Netherlands
4. VU University Medical Centre; Department of Psychiatry; Amsterdam the Netherlands
5. Albert Schweitzer Hospital; Department of Orthopaedics; Dordrecht the Netherlands
6. Waterland Hospital; Department of Orthopaedics; Purmerend the Netherlands
7. Amsterdam Rehabilitation Research Centre/Reade; Amsterdam the Netherlands