During their 20 years of activity members of the Associa tion for the Study of Internal Fixation (AO - ASIF) have made authoritative contributions to the development of internal and external fixation. The close collaboration of surgeons, basic researchers, metallurgists, engineers and the establishment of clinical documentation has made it possible to achieve a solid scientific basis for internal fixa tion. Clear definitions for the standardization of different types of osteosynthesis were possible: interfragmentary compression, splintage and buttressing as well as combina tions of these...