| abstract |
The invention concerns the fashioning of a composite socket of a joint endoprosthesis. The inorganic components of the socket have apatite and/or wollastonite crystalline phases and additionally secondary crystalline phases providing improved hydrolysis stability. The inorganic mixture consists (in mass % proportions) of 31-34 % CaO, 10-12 % P2O5, 43-46 % SiO2, 3-5 % Na2O, 2-3 % CaF2 and, to make up the 100 %, also 0.5-11 % Al2O3 and/or Zr2 and Al2O3 or TiO2 and ZrO2 or TiO2 and ZrO2 and Al2O3, whereby the proportion of TiO2 lies between 0.5 and 5 %. Essential to the invention, too, is a certain grain size distribution and radius of aperture between the ball and the socket. The result is non-wearing operation of the endoprosthesis. |