Femoral hip prosthesis
AssigneeBenoist Girard SAS
InventorsJohn Andrew Storer, Richard Eddy Field, Neil Rushton
Life of this patent
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Abstract
A prosthetic femoral component is located in a prepared socket in a femur which has been resected at a position on the proximal side of its neck. The component includes an insert portion and an enlarged proximal head portion the distal end of the head portion being adapted for location in the prepared socket. The component takes advantage of the bone at the periphery of the socket which enables the insert and the part of the head concerned to be accurately and firmly located in the bone. The presence of the bone at the outer edges of the socket helps to stabilize the component. The insert portion can be dimensioned to pass through the neck of the femur with which it is to be used or to be shorter depending upon the requirements.
Claims31
A prosthetic femoral component for location in a prepared socket in a femur which has been resected at a position on the proximal side of its neck, comprising an insert having and an enlarged proximal head portion, a distal portion of said insert being adapted to pass through said neck for location in said prepared bone socket and a part-spherical bearing element for engaging the proximal head portion of said insert, said bearing element is provided with an elongate spigot which can engage in a bore provided in said head portion, said spigot extends through said head portion and into the distal insert portion, said spigot is dimensioned and adapted to enlarge the outer dimensions of the distal insert portion to expand it into tight engagement in the bone in which it is to be fitted.
A femoral implant for implantation on a resected head of a femur, comprising:
- a first member having a part-spherical outer bearing surface with a shaft extending from an inner surface of said first member;
- and
- a second member having a head portion and an insert portion with an internal bore extending along a longitudinal axis for receiving said shaft extending from said inner surface of said first member and a distally facing stepped bone contacting surface having a plurality of steps for engaging the head of the femur, said steps of said bone contacting surface extending at greater radially outwardly distances from said axis on moving in the distal to proximal direction, said internal bore of said second member is tapered inwardly on moving from the proximal to distal direction and wherein said shaft has a diameter greater than a diameter of a distal portion of said tapered internal bore such that a wall of said insert portion surrounding said internal bore extending distally of said stepped portion expands radially outwardly.
A method of resurfacing a head of a femur comprising:
- resecting the femur head immediately above the neck;
- cutting a central bore in the remainder of the femur head;
- forming a series of radially extending steps in the remaining resected head of the femur;
- placing an insert portion having radially extending steps thereon in said bore in said head such that said implant steps are aligned and co-operate with the steps on the resected head of the femur;
- and
- placing a part-spherical bearing element on said insert portion.
Dependencies are inferred from the claim text.