[Comparative static biomechanical studies of tripod surface structures of cementless endoprostheses]

While the importance of stability of endoprosthetic surface structures has been recognized for some time there is a lack of comparative surveys and assessment indices that would permit comparison and improvement of surfaces on cementless endoprostheses.

Using separately produced, systematically mounted specimen pieces of endoprosthetic surfaces with isolated non-linked elements of varying shapes and sizes, stability parameters and stability behaviour are described. Results of tripode-structures are compared to spherical surfaces.

These investigations show clearly that geometrical attributes, the orientation and the contact of surface elements to the endoprosthetic stem influence the stability considerably more than the size of these surface elements.

Using tripode-elements with different orientation, size and density, a differentiated formation of cementless endoprosthetic surfaces is possible.