1. Department of Orthopaedic Surgery, Harvard Medical School, Massachusetts General Hospital, WACC-517, 15 Parkman Street, Boston, Massachusetts 02114, USA.
2. 1996 Maurice E. Müller Fellow, Boston Medical Centre, Department of Orthopaedics, 818 Harrison Avenue, Dowling, 2 North, Boston, Massachusetts 02118, USA.
3. Maurice E. Müller Foundation, CH 3010 Berne, Switzerland.