1. School of Medicine University of Tampere Tampere Finland
2. Department of Surgery Hospital Nova of Central Finland Jyväskylä Finland
3. Institute of Clinical Medicine and Department of Pediatrics University of Eastern Finland Kuopio Finland
4. Department of Pediatrics Kuopio University Hospital Kuopio Finland
5. Department of Orthopedics and Traumatology Tampere University Hospital Tampere Finland
6. Coxa Hospital for Joint Replacement Tampere Finland