Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Reexamination Certificate
2001-12-31
2004-03-02
Shaver, Kevin (Department: 3732)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
C623S019110
Reexamination Certificate
active
06699289
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to a glenoid component, and more particularly to an augmented glenoid component and associated method for securing the augmented glenoid component to a glenoid surface of a scapula.
BACKGROUND OF THE INVENTION
During the lifetime of a patient, it may be necessary to perform a total shoulder replacement procedure on the patient as a result of, for example, disease or trauma. In a total shoulder replacement procedure, a humeral component having a head portion is utilized to replace the natural head portion of the arm bone or humerus. The humeral component typically has an elongated intramedullary stem which is utilized to secure the humeral component to the patient's humerus. In such a total shoulder replacement procedure, the natural glenoid surface of the scapula is resurfaced or otherwise replaced with a glenoid component that provides a bearing surface for the head portion of the humeral component.
As alluded to above, the need for a shoulder replacement procedure may be created by the presence of any one of a number of conditions. One such condition is the deterioration of the patient's scapula in the area proximate to the glenoid surface as a result of, for example, glenohumeral arthritis. In such a condition, the erosion of the patient's scapula is generally observed posteriorly on the glenoid surface. Such erosion of the scapula renders treatment difficult, if not impossible, with a conventional glenoid prosthesis.
In order to treat a condition in which a portion of the scapula has been eroded, a number of glenoid prostheses have heretofore been designed. Such glenoid prostheses, known generally as augmented glenoid prostheses, have a posterior edge that is thicker than the corresponding anterior edge. In
FIG. 1A
, a heretofore-designed augmented glenoid component
100
is shown. The glenoid component
100
has a metallic backing component
102
and plastic insert
104
. The thickness of the metallic backing component
102
gradually increases from an anterior edge
106
to a posterior edge
108
thereof thereby creating a relatively smooth, arcuate-shaped medial surface
110
from which a number of posts or pegs
112
extend.
The design of the augmented glenoid component
100
, however, has a number of associated drawbacks. For example, the relatively smooth, arcuate-shaped medial surface
110
may over time lead to loosening of the augmented glenoid component
100
, thereby potentially necessitating additional surgical procedures to replace or reseat the component
100
. Further, due to the configuration of the medial surface
110
, a relatively high shear load is created along the implant-to-bone interface when the component
100
is implanted. The presence of a high shear load along the implant-to-bone interface tends to also cause loosening of the component
100
over a period of time. Post-operative loosening is the largest cause of failures of implanted glenoid components.
In
FIG. 1B
another heretofore-designed augmented glenoid component
100
a
is shown. The glenoid component
100
a
has a single component plastic body
102
a
. The thickness of the plastic body
102
a
gradually increases from an anterior edge
106
a
to a posterior edge
108
a
thereof thereby creating a relatively smooth, arcuate-shaped medial surface
110
a
from which a number of posts or pegs
112
a
extend. The design of this augmented glenoid component
100
a
, however, suffers from at least the same drawbacks as the glenoid component
100
.
In
FIG. 1C
another heretofore-designed augmented glenoid component
100
b
is shown. The glenoid component
100
b
also has a single component plastic body
102
b
. The thickness of the plastic body
102
b
gradually increases from an anterior edge
106
b
to a posterior edge
108
b
thereof thereby creating a relatively smooth medial surface
110
b
from which a keel
114
extends. The design of this augmented glenoid component
100
b
, however, suffers from at least the same drawbacks as the glenoid components
100
and
100
a.
What is needed therefore is an augmented glenoid component that overcomes one or more of the above-mentioned drawbacks. What is further needed is an augmented glenoid component that is less susceptible to postoperative loosening relative to heretofore designed glenoid components.
SUMMARY OF THE INVENTION
The subject invention is a glenoid component and associated method for securement thereof to a glenoid surface of a scapula. Particularly, the subject invention is an augmented glenoid component and associated method for securement thereof to a glenoid surface of a scapula. More particularly, the subject invention is an augmented glenoid component having an interruption or the like and an associated method for securement of the augmented glenoid component to a glenoid surface of a scapula.
In one form, the interruption is defined by a buttress, step, shoulder, ledge, interface or the like that extends from a surface of a component body that defines at least a portion of the present augmented glenoid component. The body may also include anchoring. In one form, the anchoring of the body may comprise one or more anchors. An anchor may extend entirely from the surface of the body, entirely from the interruption, or from both the interruption and the surface (i.e. straddling).
In accordance with an embodiment of the subject invention, there is provided an augmented glenoid component for securement to a glenoid surface of a scapula so as to provide a bearing surface for a head portion of a humerus. The augmented glenoid component includes a body and a buttress. The body has a first body surface configured to contact the glenoid surface of the scapula, and a second body surface configured to be contacted by the head portion of the humerus. The buttress is formed in the first body surface of the body.
In accordance with another embodiment of the subject invention, there is provided an augmented glenoid component for securement to a glenoid surface of a scapula so as to provide a bearing surface for a head portion of a humerus. The augmented glenoid component includes a body, medial surface on the body, a humerus surface on the body, an interruption, and anchoring. The medial surface is configured to contact the glenoid surface of the scapula. The humerus surface is configured to be contacted by the head portion of the humerus. The interruption extends from the medial surface and defines a first interruption surface positioned relative to the medial surface at an angle &thgr; in which 45°≦&thgr;≦135°, and a second interruption surface positioned relative to a line parallel to the first body surface an angle &phgr; in which 0°≦&phgr;≦90°.
In accordance with a further embodiment of the subject invention, there is provided a method of securing an augmented glenoid component to a glenoid surface of a scapula so as to provide a bearing surface for a head portion of a humerus. The augmented glenoid component has: (i) a body having: (a) a first body surface configured to contact the glenoid surface of the scapula, and (b) a second body surface configured to be contacted by the head portion of the humerus; and (ii) a buttress extending from the first body surface. The method includes the steps of (a) forming a buttress-shaped recess in the glenoid surface of the scapula; and (b) securing the augmented glenoid component to the glenoid surface of the scapula such that: (i) the first body surface is positioned in contact with the glenoid surface of the scapula, and (ii) the buttress is positioned in the step-shaped recess.
In all embodiments, the present augmented glenoid component provides good stabilization after implant. Further, the present augmented glenoid component converts normal high shear loads into compressive loading thereby reducing stress on the glenoid component. The present augmented glenoid component may be used to correct bone defects or wear.
It is therefore an object of the subject invention to provide a new and useful a
Iannotti Joseph P.
Williams, Jr. Gerald R.
DePuy Orthopaedics, Inc.
Maginot Moore & Beck
Melson Candice C.
Shaver Kevin
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