Joint endoprosthesis with Al2O3 ceramic head and a composite socket and process for making it

摘要

PCT No. PCT/DE90/00913 Sec. 371 Date Jul. 28, 1992 Sec. 102(e) Date Jul. 28, 1992 PCT Filed Nov. 28, 1990 PCT Pub. No. WO91/08000 PCT Pub. Date Jun. 13, 1991.A composite socket of a joint endoprosthesis may be fashioned in which the inorganic component of the socket has 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, beyond the 100% of the above components, 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.