1. R.F.M.R. Kersten, MD, Department of Orthopedics, Martini Hospital Groningen, Groningen, the Netherlands, and Department of Orthopedics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
2. M. Stevens, PhD, Department of Orthopedics, University Medical Center Groningen, University of Groningen.
3. J.J.A.M. van Raay, MD, PhD, Department of Orthopedics, Martini Hospital Groningen.
4. S.K. Bulstra, MD, PhD, Department of Orthopedics, University Medical Center Groningen, University of Groningen.
5. I. van den Akker-Scheek, PhD, Department of Orthopedics, Martini Hospital Groningen, and Department of Orthopedics, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, the Netherlands.