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.
Type:
Grant
Filed:
March 31, 1993
Date of Patent:
May 24, 1994
Assignee:
Orthopaedic Technology B.V.
Inventors:
Hendrik W. J. Huiskes, Franciscus A. M. Ypma, Pierre J. T. M. Jaspers
Abstract: According to the present invention, the stress patterns at the interface between bone and cement of an existing prosthesis are calculated by a finite element model. For this model the external load, material properties and boundary conditions are provided. By means of advanced digital computers, stresses and strains in the model are calculated. Desired stress patterns are achieved through an optimization procedure to determine that geometry which generates those stress patterns which approximate the desired ones best.
Type:
Grant
Filed:
November 3, 1988
Date of Patent:
August 20, 1991
Assignee:
Orthopaedic Technology B.V.
Inventors:
Johannes F. A. M. Ypma, Hendrik W. J. Huiskes, Pierre J. T. M. Jaspers