1. University Hospital Motol, V, Uvalu 84, Prague, Czech, Republic.
2. University Hospital Ceske, Budejovice, B Nericove 585/54, 370 87, Ceske Budejovice, Czech Republic.
3. Dumfries and Galloway Royal Infirmary, Bankend Road, Dumfries DG1 4AP, UK.
4. Department of Orthopaedics, Hamad General Hospital, P. O. Box 3050, Doha, Qatar.