Prosthesis shaft

US4978359A · kind A · utility

Assignee

• Thera Patent GmbH & Co KG Gesellschaft fur Industrielle Schutzrechte · DE

Inventors

• Klaus Wilhelm · Rosenheim, DE
• Johann Bauer
• Werner Schmitt · Starnberg, DE
• Wolf-Dietrich Herold · Hechendorf, DE
• Peter Koran · Weilheim, DE
• Erich Wanek · Kaufering, DE
• Oswald Gasser · Hanerau-Hademarschen, DE

Key dates

• Filing date: Apr 27, 1989
• Grant date: Dec 18, 1990
• Expiry date: Apr 27, 2009

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61F2002/3631
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

For anchoring a prosthesis within a bone by means of a bone cement (32), prothesis shaft has a surface which is formed by the surfaces of a plurality of spheres (23 . . . 25) partially penetrating each other and having radii which decrease from the proximal towards the distal shaft end. The transitional zones between adjacent spheres (23 . . . 25) are concavely rounded. This shape is especially suited for use with a glass ionomer-type bone cement, because the shaft exerts substantially only compressive forces on the cement, whereas tensile and notch stresses, with respect to which this kind of cement exhibits little resistance, are largely avoided.