Karl Knahr completed his medical studies at the University of Vienna in 1971 and subsequently trained as an orthopaedic surgeon at the Orthopaedic University Clinic of Vienna. In 1988 he became Head of the 2nd Orthopaedic Department at the Orthopaedic Hospital, Vienna-Speising and in the following year he was appointed Professor of Orthopaedic Surgery at the University of Vienna. For more than a decade, Professor Knahr has been the Austrian National Delegate to SICOT (Société Internationale de Chirurgie Orthopédique et de Traumatologie), President and current Treasurer of the Austrian Society for Orthopaedic Surgery, and Austrian National Delegate to EFORT. Since 2005 he has been a member of the EFORT Executive Committee. He is currently a member of the editorial boards of International Orthopaedics and the Archives of Orthopaedic and Trauma Surgery and previously served as an editorial board member for the Journal of Arthroplasty. Professor Knahr has published widely on the subjects of tribology and hip arthroplasty.