[A new standard method for experimental for measuring cement coat strength in endoprosthesis implantation]

The distribution of bone cement around an endoprosthesis influences its stability over the long term. We have developed a new method for the experimental measurement of the cement mantle thickness of an endoprosthesis. The use of this computer-aided procedure is described in a hip prosthesis. Transverse sections of a human femur containing a cemented stem were prepared, recorded with a CCD camera and the images fed into a computer. The image-processing software differentiated the metal and bone cement on the basis of the different colours. Radial lines were drawn from the calculated centre of gravity of the stem, and the cement thickness was measured automatically along these lines. In our experiment, the accuracy of the method was 0.2 mm. This method of measuring the thickness of the cement mantle is accurate, rapid and practical.