The last years showed an increasing demand especially of younger patients for bone protecting total hip arthroplasty. Apart from the well known cemented versions a cementless implant with a variable short stem has been developed. It also consists on a metal backed metal inlay.

The femoral component of the Eska Hip Resurfacing System is surfaced on the bone side with the well experienced metal-spongiosa II three dimensional structure. The femoral component can be combined with a short stem either of 30 or 50 mm of length. The diameter increases in two millimeter steps. The socket component is also covered with the metal-spongiosa II structure. The cup inlay is secured by conical fixation and can be changed.

We think the implant offers a very helpful new development in the cementless hip resurfacing arthroplasty. First technical problems have been solved.

Summary: The tribological development in the metal-metal partners brought out a new surface texture for the femoral cup. A reduction of the coefficient of friction and a reduction of the metallic abrasion on almost half are secured in lab tests. First clinical applications took place in our hospital.

Question: Total hip surface replacement in metal-metal partners have, although in small quantity, metallic abrasion, which leads to clear increases of the serum concentration of the serological level. The long-term effect on the organism is not so far clarified. A reduction of the abrasion quantity is however worthwhile. Is a structural change of the surface of the femoral cup suitable to cause such a reduction of the metallic abrasion?

Methodology: Derived from bionic systems in nature the surface of total hip surface replacement was changed by dimple like surface, so that in presence of liquid an accumulation of liquid between both sliding partners takes place and takes place thus on this liquid film the articulation. Laboratory tests on a simulator were accomplished, in order to examine whether the desired reduction of the abrasion is obtained. This surface is called Biosurf-surface.

Results: Simulator wear tests of the standard total hip surface replacement in the metal-metal partner have been compared with the Biosurf-surface. The simulator attempts showed that after 5 million motion cycles the Biosurf –system the abrasion quantity in milligram reduces to more than a half. By this clear reduction of particles the concentration of the metal ions which can be expected in the serum is clearly smaller, so that thereby a contribution is made to reduce the possibly damaging influence of metallic ions in the organism.