In recent years the 'Tribology Day' has become a recognized highlight of the EFORT Congress, and at the 2012 Congress in Berlin an entire day was once again devoted to tribology in total hip arthroplasty. EFORT decided that, given the wide interest in tribology, publication of the presentations would be warmly welcomed by fellow professionals who were unable to attend. The resulting book includes all presentations delivered on the day and covers a range of interesting topics. Up-to-date information is provided on the various articulating materials, and all the articulations recently used in total hip arthroplasty are discussed, with provision of clinical data. The book will be of interest not only to experienced surgeons but also to trainees and residents who wish to extend their knowledge of total hip arthroplasty.?

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.