The morphological investigation of endoprostheses and the evaluation of the reaction with the surrounding bone tissue require the use of new preparation techniques. A standardized procedure of preparation is suggested to enable a comparison among various study groups. After removing the specimens (at autopsy), x-rays are taken, followed by separation into horizontal and longitudinal sections. These sections are undecalcified embedded retaining the implant/bone interface and grounded to thickness of 5-10 mu. First results of a quantitative analysis of bone loss are presented.