Endo-prosthesis, a femoral head prosthesis and an acetabulum prosthesis
AssigneeOrthopaedic Technology B.V.
InventorsHendrik W. J. Huiskes, Franciscus A. M. Ypma, Pierre J. T. M. Jaspers
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Abstract
A prosthesis for insertion into a long bone includes a stem which has been shaped so as to evenly distribute low stress to the bone. A synthetic resinous sheath surrounds the stem which effects a contact surface between the stem and the bone. The prosthesis includes an extension which extends outwardly of the bone and has a ball and socket thereon.
Claims11
A femoral head prosthesis for insertion into a long bone having a canal therein disposed along an intramedullary axis of the long bone which has been resected along a resection plane to expose the interior canal thereof, and wherein said prosthesis is modeled relative to the long bone, said prosthesis comprising a neck extending above the resection plane wherein the prosthesis is inserted into the long bone;
- and an elongated stem having a continuous protrusion formed with a proximal taper and a distal taper said proximal taper extending continuously only along the medial side to an area below the resection plane terminating in a apex region of said protrusion and the digital taper extending continuously from the apex region of said protrusion distally and continuously only along the medial side, such that, after having been inserted into the canal, the resulting stresses between said stem and contact surfaces between the stem and the long bone defining the canal are minimized and evenly distributed in accordance with said model.
A femoral head prosthesis for insertion into a long bone having a canal therein disposed along an intramedullary axis of the long bone which has been resected along a resection plane to expose the canal interior thereof, said prosthesis comprising a stem and a having a narrow distal portion and terminal stem tip and a widened proximal portion below the resection plane and a neck portion extending between the widened proximal portion to the femoral head above the resection plane, a first spacer having an opening for receiving the neck therein and for abutting the long bone along the resection plane, said first spacer for radially positioning the neck with respect to the canal, and a second spacer having an opening disposed off center thereof for receiving the terminal stem tip therein medially of said intramedullary axis and for closely engaging a distal inner wall portion of the canal for positioning the narrow stem portion within said canal, said second spacer being formed with a through opening having an inlet and an outlet in communication with the interior of the long bone, and said distal and proximal portions having a shape, such that, after having been inserted into the canal, stresses between said stem and the bone defining the canal have values which are minimized and evenly distributed therealong.
Dependencies are inferred from the claim text.