Joint endoprosthesis with Al.sub.2 O.sub.3 ceramic head and a composite socket and process for making it

US5338771A · kind A · utility

Assignee

• Eska Medical Luebeck Medizin Technik GmbH · DE

Inventors

• Gerd Neumann · Greding, DE
• Peter Hutschenreuther · Stadtroda, DE
• Willfried Glien · Hermsdorf, DE
• Dagmar Raab · Ilmenau, DE
• Barbara Leuner · Ilmenau, DE
• Gabriele Steinborn · Berlin, DE
• Georg Berger · Panketal, DE

Key dates

• Filing date: Jul 28, 1992
• Grant date: Aug 16, 1994
• Expiry date: Jul 28, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S623/901
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

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% P.sub.2 O.sub.5, 43-46% SiO.sub.2, 3-5% Na.sub.2 O, 2-3% CaF.sub.2 and, beyond the 100% of the above components, also 0.5-11% Al.sub.2 O.sub.3 and/or Zr.sub.2 and Al.sub.2 O.sub.3 or TiO.sub.2 and ZrO.sub.2 or TiO.sub.2 and ZrO.sub.2 and Al.sub.2 O.sub.3, whereby the proportion of TiO.sub.2 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.