Publication
The interfacial micromotion is closely associated to the long-term success of cementless hip prostheses. Various techniques have been proposed to measure them, but only a limited number of points over the stem surface can be measured simultaneously. In this paper, we propose a new technique based on μCT to measure locally interfacial micromotions between the metallic stem and the surrounding bone. Tantalum beads were spread and stuck at the stem and endosteal surfaces. Relative micromotions were measured at different loading amplitudes. The error was 10 μm and the maximal micromotion was 60 at 1400 N. This pilot study provided a local measurement of the micromotion at 8 points simultaneously, but this technique could be easily extended to a couple of hundreds of points covering the entire stem surface. This new technique could be used to compare the primary stability of different cementless stem designs, and other implants.
Matthias Lütolf, Sonja Giger, Marlen Knobloch, Mergim Ramosaj