The main problem with regard to alloplastic joints is the loosening of the implant. Twenty years ago, Charnley first introduced bone cement to hip surgery, enabling total hip replacement to be practised on a larger scale. There is no question, however, that new approaches must be found to solving the problems of implant loosening, either by developing a new type of cement or by directly anchoring the implant without using ce- ment. Much research has been done in this direction in recent years. The methods which have already been tested or are currently being tested were presented and discussed at a symposium on Cementless Fixation of Endoprostheses organized by the Orthopaedic Clinic of the University of Basel and held on 24-26 June 1982. Various possible ap- proaches which might be realized in practice were discussed in a relaxed atmosphere. In addition to the biomechanical bases of cementless fixa- tion of endoprostheses, the various models were discussed, with special regard to their biocompatibility, physical characteristics, design, clinical applicability, and previous clinical experience. This book contains the papers delivered at this symposium.