1. Department of Orthopaedic Surgery, Academic Medical Centre, Amsterdam - The Netherlands
2. Department of Orthopaedic Surgery, Onze Lieve Vrouwe Gasthuis, Amsterdam - The Netherlands
3. Department of Orthopaedic Surgery, Isala Klinieken, Zwolle - The Netherlands
4. Division of Orthopaedic Surgery, McMaster University, Hamilton - Canada