U.S. patent application number 13/007355 was filed with the patent office on 2011-07-07 for apparatus for fitting a shoulder prosthesis.
This patent application is currently assigned to Tornier SAS. Invention is credited to Pascal Boileau, Pierric Deransart, Irene Gosset, Gilles Walch.
Application Number | 20110166661 13/007355 |
Document ID | / |
Family ID | 38474292 |
Filed Date | 2011-07-07 |
United States Patent
Application |
20110166661 |
Kind Code |
A1 |
Boileau; Pascal ; et
al. |
July 7, 2011 |
APPARATUS FOR FITTING A SHOULDER PROSTHESIS
Abstract
Method and set of surgical instruments for fitting a shoulder
prosthesis, and the shoulder prosthesis. The proposed method seeks
to interpose a bone graft between the previously prepared glenoid
surface of a scapula of a patient's shoulder and the face of a
glenoid prosthetic component opposite the articular surface. The
set of instruments permit the bone graft to be taken from the upper
epiphysis of the humerus, either in situ or ex vivo.
Inventors: |
Boileau; Pascal; (Nice,
FR) ; Walch; Gilles; (Lyon, FR) ; Gosset;
Irene; (Le Touvet, FR) ; Deransart; Pierric;
(Grenoble, FR) |
Assignee: |
Tornier SAS
Saint Ismier
FR
|
Family ID: |
38474292 |
Appl. No.: |
13/007355 |
Filed: |
January 14, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12020913 |
Jan 28, 2008 |
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13007355 |
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60888437 |
Feb 6, 2007 |
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60971762 |
Sep 12, 2007 |
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61015042 |
Dec 19, 2007 |
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Current U.S.
Class: |
623/19.13 ;
623/19.14 |
Current CPC
Class: |
A61B 17/1778 20161101;
A61B 17/86 20130101; A61F 2002/4022 20130101; A61F 2/28 20130101;
A61F 2/40 20130101; A61B 17/1615 20130101; A61F 2002/30878
20130101; A61F 2310/00359 20130101; A61F 2/4081 20130101; A61F
2002/30225 20130101; A61B 17/1684 20130101; A61F 2/4612 20130101;
A61F 2230/0065 20130101; A61F 2002/2835 20130101; A61F 2002/30677
20130101; A61F 2002/30433 20130101; A61F 2220/0041 20130101; A61F
2230/0069 20130101; A61F 2220/005 20130101; A61B 17/1637 20130101;
A61F 2/4003 20130101; A61F 2002/2817 20130101; A61F 2002/30448
20130101; A61F 2002/30884 20130101; A61F 2/30734 20130101; A61F
2/30767 20130101; A61F 2002/30911 20130101; A61F 2002/30736
20130101; A61F 2310/00796 20130101; A61F 2/4644 20130101; A61B
17/1635 20130101; A61F 2002/4085 20130101; A61F 2002/302
20130101 |
Class at
Publication: |
623/19.13 ;
623/19.14 |
International
Class: |
A61F 2/40 20060101
A61F002/40 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 30, 2007 |
FR |
0700622 |
Claims
1. A shoulder prosthesis adapted for implantation in a glenoid of a
patient, the prosthesis comprising: a head portion having an
articulation surface adapted for articulation with a humeral head
and an engagement surface opposite the articulation surface; a bone
graft having a medial surface and a distal surface and defining a
thickness between the medial and distal surfaces, the medial
surface having a shape complementary to the glenoid surface and the
distal surface having a shape complementary to the engagement face
of the head portion; and an anchor structure connected to the
engagement surface and adapted to extend through the bone graft and
into the glenoid surface, the anchor structure being adjustable in
overall length to accommodate the thickness of the bone graft such
that the anchor structure extends through and projects beyond the
bone graft upon engagement of the distal surface of the bone graft
with the engagement surface of the head portion.
2. The prosthesis of claim 1, wherein the bone graft is at least 7
mm thick.
3. The prosthesis of claim 1, wherein the anchor structure is
adjustable to at least 20 mm in length.
4. The prosthesis of claim 1, wherein the anchor structure includes
a first portion and a second portion telescopically received in the
first portion, the second portion being extendable from the first
portion to adjust the overall length of the anchor structure.
5. The prosthesis of claim 1, wherein the anchor structure includes
a first portion having a first length and a second portion
releasably connected to the first portion to extend the overall
length of the anchor structure.
6. The prosthesis of claim 1, wherein the bone graft includes metal
material having a trabecular structure.
7. The prosthesis of claim 1, wherein the bone graft includes
structured porous tantalum.
8. The prosthesis of claim 1, wherein the bone graft is taken from
a bone in the patient.
9. The prosthesis of claim 1, wherein the bone graft comprises an
upper epiphysis of a humerus.
10. The prosthesis of claim 1, wherein the bone graft comprises at
least one of an allograft, a xenograft, a natural material, and a
synthetic material.
11. The prosthesis of claim 1, wherein the bone graft defines an
outer lateral face and the prosthesis further comprises a
reinforcing structure that at least partially surrounds the outer
lateral face of the bone graft.
12. The prosthesis of claim 1, wherein the bone graft defines an
outer lateral face and the glenoid component at least partially
surrounds the outer lateral face of the bone graft.
13. The prosthesis of claim 1, wherein the bone graft defines an
outer lateral face and the prosthesis further comprises a
reinforcing structure located between the medial surface of the
bone graft and the glenoid surface, the first reinforcing structure
comprising first side walls supporting the outer lateral face of
the bone graft.
14. A shoulder prosthesis system adapted for replacement of a
glenohumeral joint of a patient, the prosthesis comprising: a
humeral head having a humeral articulation surface; and a glenoid
component including: a head portion having an articulation surface
in articulating engagement with the humeral articulation surface of
the humeral head; a bone graft having a medial surface and a distal
surface and defining a thickness between the medial and distal
surfaces; and an anchor structure connected to the engagement
surface and secured into a glenoid surface of the glenohumeral
joint, the anchor structure engaging the bone graft and restricting
lateral movement of the bone graft, the anchor structure being
adapted to be adjusted in overall length to accommodate the
thickness of the bone graft.
15. The system of claim 14, wherein the anchor structure includes a
first portion and a second portion, the second portion being
telescopically received in the first portion and extendable from
the first portion to adjust the overall length of the anchor
structure.
16. The system of claim 14, wherein the anchor structure includes a
first portion and a second portion releasably secured to the first
portion to extend the overall length of the anchor structure.
17. A method of repairing a glenohumeral joint, the method
comprising: receiving a bone graft with an anchor structure of a
glenoid component, the bone graft having a thickness between a
medial surface and a distal surface of the bone graft; engaging the
medial surface of the bone graft with an engagement surface of a
head structure of the glenoid component, the head structure having
an articulation surface that is adapted to articulate with a
humeral head, the articulation surface being positioned opposite
the engagement surface; restricting lateral movement of the bone
graft with the anchor structure of the glenoid component, the
anchor structure of the glenoid component projecting from the
engagement surface of the glenoid component; adjusting an overall
length of the anchor structure of the glenoid component to
compensate for the thickness of the bone graft; and securing the
anchor structure of the glenoid component into a boney structure of
the glenoid.
18. The method of claim 17, further comprising engaging the
articulation surface of the glenoid component with a natural
humeral head.
19. The method of claim 17, further comprising engaging the
articulation surface of the glenoid component with a prosthetic
humeral head.
20. The method of claim 17, further comprising shaping a natural
humeral head to define a humeral engagement surface and engaging
the articulation surface of the glenoid component with the humeral
engagement surface.
21. The method of claim 17, wherein the anchor structure includes a
first portion having a first length and a second portion releasably
connected to the first portion to extend the overall length of the
anchor structure, and further wherein the bone graft is received by
the first portion and then the second portion is releasably
connected to the first portion.
22. The method of claim 17, wherein the bone graft is received by
the engagement surface and then the first portion of the anchor
structure is connected to the head structure.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part
application of U.S. patent application Ser. No. 12/020,913 filed
Jan. 28, 2008, entitled "Method and Apparatus for Fitting a
Shoulder Prosthesis," which claims priority to French Application
No. 0700622, entitled "Methode et ensemble d'instrumentation
chirurgicale pour poser une prothese totale d'epaule inversee, et
prothese correspondante," filed Jan. 30, 2007 and also claims the
benefit of U.S. Provisional Application Ser. Nos. 60/888,437 filed
Feb. 6, 2007, 60/971,762 filed Sep. 12, 2007 (both entitled "Method
and Apparatus for Fitting an Inverted Shoulder Prosthesis") and
U.S. Provisional Application Ser. No. 61/015,042, entitled
"Intra-Articular Joint Replacement," filed Dec. 19, 2007, the
complete disclosures of each of which are hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an inverted or an
anatomical shoulder prosthesis including a graft to lateralize a
glenoid component of the shoulder prosthesis.
BACKGROUND OF THE INVENTION
[0003] Total shoulder prostheses, are commonly said to be inverted
when they comprise, on the one hand, a glenoid part integral with
the glenoid surface of a scapula of a patient's shoulder and
delimiting a convex articular surface and, on the other hand, a
humeral part integral with the humerus of the shoulder and
delimiting a concave articular surface, the cooperation of these
articular surfaces allowing an articulated connection to be
reproduced at the shoulder. With this type of prosthesis, it is
common, during adduction movement of the shoulder, for the lower
portion of the humeral prosthetic part to strike the pillar of the
scapula, i.e. the lower portion of the bone glenoid surface
located, when the patient stands upright, just below the glenoid
prosthetic part. This interference between the humeral prosthetic
part and the scapula limits the range of the adduction movement and
may cause pain to the patient or even lead to the prosthesis
becoming dislodged, in particular by osteolysis of the scapula.
BRIEF SUMMARY OF THE INVENTION
[0004] Various aspects of the invention relate to surgical methods
and corresponding surgical instruments for reducing risk of
interference between the scapula and the humeral part of an
inverted or an anatomical shoulder prosthesis. All references to a
"shoulder prosthesis" should be interpreted to include a total
shoulder prosthesis with a humeral component and a glenoid
component (including anatomical, inverted, or interpositional
configurations), or a partial shoulder prosthesis with a glenoid
component with an anatomical or resurface humeral head.
[0005] Some embodiments relate to a surgical method for fitting an
inverted shoulder prosthesis, the prosthesis including a glenoid
component having a convex articular surface and an opposing face,
this fitting method including successive preoperative steps in
which a graft is provided, the graft is placed on the previously
prepared glenoid surface of a scapula of a patient's shoulder, and
the glenoid component is implanted so as to cover the graft
positioned on the glenoid surface with the opposing face of the
glenoid component and to anchor the glenoid component in the
glenoid surface through the graft. In some embodiments, a geometric
center of articulation of the glenoid component is situated at the
bone face in the glenoid surface, where a radius of curvature of a
convex articular surface of the glenoid component is selected so a
center of rotation of the glenoid component is in or behind a plane
comprising a distal surface of the graft.
[0006] In some embodiments, the method includes "lateralizing" the
glenoid component relative to the patient's scapula, withdrawing
the glenoid component from the patient's scapula in a plane frontal
to the patient, by interposing the graft between this glenoid
component and the glenoid surface. In other words, the graft forms
an outer lateral extension of the glenoid surface, extending the
scapula, whereas the combination of the graft and the prosthetic
glenoid component forms a composite prosthetic unit. The glenoid
component is optionally implanted so as to cover a side of the
graft opposing the glenoid surface, where the component includes a
bone anchoring structure or anchor portion, such as a central tail,
sufficiently elongate to pass through the graft and in the bone of
the scapula delimiting the glenoid surface. According to some
embodiments, once the graft has fused with the glenoid surface, a
distal surface of the graft becomes the effective glenoid surface.
References to glenoid surface should be interpreted to include a
prepared or an unprepared exposed surface of a glenoid cavity.
[0007] In some embodiments, an articular face of the glenoid
component occupies, relative to the scapula, a position laterally
more remote than a position the articular face would occupy were
the graft omitted. Removing the glenoid component laterally helps
reduce risk of interference between the pillar of the scapula and
the lower portion of the humeral prosthetic part cooperating with
the glenoid articular face. The lateralization of the prosthetic
glenoid component also helps increase tension in the rotator
muscles of the shoulder and the co-adaptation vector of the deltoid
muscle, which helps stabilize the prosthetic glenoid and humeral
components and promote better mobility in relative rotation with a
lower risk of shoulder dislocation. Furthermore, compared to
typical inverted shoulder prostheses, which can be described as a
medialized prostheses, lateralized prostheses according to various
embodiments help restore some of the curved surface of the
patient's shoulder, giving the shoulder a more pleasing appearance
than the "coat hanger" appearance conferred by medialized
prostheses.
[0008] Some embodiments relate to glenoid components that include
adjustable length tails, or anchoring structures for use with
grafts having a variety of thicknesses, according to embodiments of
the present invention. For example, in some embodiments, a surgeon
or other user selects a desired bone graft thickness and adjusts
the overall length of an anchoring portion of the glenoid component
for use with that graft thickness. By adjusting the overall length
of the anchoring structures, the glenoid components are better able
to facilitate lateralization of the center of rotation of the
glenoid component with a secure affixation into the boney structure
forming the glenoid, for example, as well as additional or
alternative advantages.
[0009] According to various embodiments, complete exposure of the
glenoid surface is not required and is optionally limited to
positioning of the graft, promoting efficiency and reproducibility.
The graft is optionally taken from the patient, although
allografts, xenografts, metals, natural or synthetic materials are
employed as desired. In some embodiments, the graft is taken from
the upper epiphysis of the humerus of the patient's shoulder, such
that the graft originates from the patient, thereby helping to
limit risk of rejection, poor biological compatibility, and
transmission of disease or infection, for example. Moreover,
efficiencies are realized in that often times in order to implant a
corresponding humeral component, the epiphysis of the patient's
humerus is to be prepared by withdrawing a substantial amount of
cancellous bone matter from this epiphysis which can then be used
to provide the graft rather than, for example, simply discarding
such bone matter. Accordingly, in some embodiments, the method
includes a shaping step in which the bone matter forming the upper
humeral epiphysis is shaped into a one-piece volume extending in
length about an axis inclined relative to the longitudinal
direction of the humerus, and a cutting step in which the volume of
bone matter is removed from the humerus by cutting the humeral
epiphysis transversely to the axis of this volume, the volume of
bone matter thus removed forming the graft.
[0010] According to some methods, a surgical joint repair includes
adjusting a length of the graft along an axis of a volume of bone
matter and shaping respective longitudinal end faces of the graft
to be substantially complementary to an opposing face of the
glenoid component and the glenoid surface previously prepared.
During the shaping step, the shaped volume of bone matter is chosen
from a cylinder and a frustum of a cone, for example, centered on
the axis of the shaped volume of bone matter. Before or during the
shaping step, the end of the upper humeral epiphysis is resected as
desired, for example, over a first plane. During the cutting step,
the humeral epiphysis is optionally cut over a second plane, the
first and second planes being transverse to the axis of the shaped
volume of bone matter. A relative inclination of the first and
second planes is adjusted as desired. During or after the shaping
step, a recess is optionally formed that is centered on the axis of
the volume of bone matter in the humeral epiphysis. In some
embodiments, the glenoid component is anchored in the glenoid
surface through the recess and, before carrying out the shaping
step, a marker pin is inserted into the humeral epiphysis, thereby
allowing, during the shaping step, positioning of the axis of the
volume of bone matter relative to the humerus.
[0011] According to some other embodiments, rather than taking the
graft from the patient's humeral epiphysis, the graft is taken from
a bone region in the patient other than the upper humeral
epiphysis, such as the patient's ilium, or the graft is formed as
an allograft, a graft of synthetic origin, a graft of metallic
origin, combinations thereof, or other material. For example, in
some embodiments a protection layer is attached to at least a part
of the graft that is not in contact with the glenoid surface and at
least a part of the opposing face of the glenoid component is
supported on the protection layer. In some embodiments, some or all
of the surfaces on the glenoid component that engage with the graft
are covered with hydroxyapatite or materials having a functionally
similar surface state, such as a honeycomb surface state, allowing
bone adhesion and rehabilitation to be improved. Selected surfaces
of the glenoid component may be constructed of materials that
facilitate fusion with bone, such as those disclosed in U.S. Pat.
No. 7,250,550.
[0012] According to still other embodiments, the graft includes a
puree of bone substance (e.g, originating from the patient, in such
as from the upper epiphysis of the humerus, or from another,
source, such as a synthetic or metallic source). In some
embodiments, the puree of bone substance is advantageously used
with a protective structure, such as a lattice shaped into a cage
that is filled with the puree. The lattice cage optionally
facilitates good exchange of biological flows between the puree
forming the graft and the surrounding tissues of the shoulder.
[0013] The invention also relates to a set of surgical instruments
for fitting a shoulder prosthesis. The set includes a shaping
ancillary instrument that shapes the bone matter forming the upper
humeral epiphysis of a humerus into a one-piece volume extending in
length about an axis inclined relative to the longitudinal
direction of the humerus, and a cutting ancillary instrument that
cuts the humeral epiphysis shaped by the shaping ancillary
instrument, for cutting the volume of bone matter transversely to
the axis of this volume. The cutting ancillary instrument is
optionally used to remove the volume of bone matter from the
humerus that is formed into a graft.
[0014] The set of instruments according to the invention allows
implementation of the fitting method defined hereinbefore, the
shaping and cutting steps of which are respectively carried out by
the shaping and cutting ancillary instrument. The volume of bone
matter removed from the humerus using the cutting ancillary
instrument can thus be used as the bone graft for carrying out the
general fitting method defined hereinbefore in order laterally to
offset the convex articular surface of a glenoid component of the
prosthesis relative to the scapula of the patient's shoulder,
during implantation of this glenoid component.
[0015] According to advantageous features of this set of
instruments, taken in isolation or in any technically feasible
combination:
[0016] the set comprises a resecting instrument for resecting the
end of the humeral epiphysis, which resecting instrument is either
carried by a specific resection ancillary instrument, distinct from
the other ancillary instrument of the set or integrated in the
shaping ancillary instrument;
[0017] the resecting instrument comprises a planar reamer so as to
resect the humeral epiphysis over a first plane transverse to the
axis of the volume of bone matter;
[0018] the set comprises a humeral epiphysis drilling instrument
which is adapted to form a recess, centered on the axis of the
volume of bone matter, in the humeral epiphysis and which is either
integrated in the shaping ancillary instrument, or the resection
ancillary instrument, or is carried by a specific drilling
ancillary instrument distinct from the other ancillary instrument
of the set;
[0019] the set comprises a marker pin or a similar marker
instrument capable of being inserted into the humeral epiphysis and
suitable for guiding the shaping ancillary instrument and
optionally at least one of the other ancillary instrument of the
set;
[0020] the set comprises an inserting ancillary instrument for
inserting the marker pin into the humeral epiphysis, which
inserting instrument is suitable for adjusting the direction of
insertion of this pin relative to the humerus;
[0021] the inserting ancillary instrument comprises, on the one
hand, a rounded bell-shaped body configured internally to cover the
upper humeral epiphysis in the manner of a cap and, on the other
hand, a guide for applying the marker pin, which guide opens into
the body;
[0022] the shaping ancillary instrument comprises a bell-shaped saw
which is suitable for cutting the bone matter forming the humeral
epiphysis by shaping it into the volume of bone matter;
[0023] the saw has an optionally perforated cylindrical or
frustoconical inner face so as to provide the volume of bone matter
with the overall shape of a cylinder or frustum of a cone, centered
on the axis of this volume;
[0024] the cutting ancillary instrument comprises a tubular block
suitable for being slipped about the volume of bone mass shaped by
the shaping ancillary instrument, this block delimiting, at its
longitudinal end turned during operation toward the humerus, an
incision zone in the humeral epiphysis, in order to cut the volume
of bone matter transversely to the axis thereof;
[0025] the incision zone forms a transverse slot for the passage of
a saw blade or the like, in order to cut the volume of bone matter
over a second plane transverse to the axis of this volume; and
[0026] the cutting ancillary instrument comprises an annular body
adapted to be mounted around the humeral epiphysis while
surrounding at least the volume of bone matter shaped by the
shaping ancillary instrument, this body delimiting a guide surface
for a cutting instrument to cut at least the volume of bone matter
transversely to its axis.
[0027] The invention also relates to an inverted shoulder
prosthesis comprising a glenoid component having a convex articular
surface and an opposing face, wherein the prosthesis comprises a
protection layer for protecting a graft interposed, when the
prosthesis is fitted, between said opposing face and the glenoid
surface of a scapula of a patient's shoulder, this protection layer
being suitable for both covering at least a part of the graft that
is not in contact with the glenoid surface and forming a support
for at least a part of said opposing face.
[0028] The graft protected by the protection layer of the
prosthesis according to the invention can be taken from the upper
humeral epiphysis using the set of instruments defined
hereinbefore, or else be chosen from a graft taken from a bone
region in the patient other than the upper humeral epiphysis, in
particular from the patient's ilium, an allograft and a graft of
synthetic or metallic origin. In practice, this prosthesis is
fitted in accordance with the general method defined
hereinbefore.
[0029] According to advantageous features of this prosthesis, the
prosthesis optionally includes a protection layer, such as for
example, a layer of hydroxyapatite or other material that has a
functionally similar surface state, such as a honeycomb surface
state, allowing bone adhesion and rehabilitation to be improved. In
another embodiment, the protection layer includes a shape of a ring
suitable for surrounding, in a close-fitting manner, the portion of
the bone graft not in contact with the glenoid surface, it being
appreciated that, in practice, this ring is used for a one-piece
graft obtained, in particular, by the set of instruments as defined
hereinbefore. The protection layer may also be a lattice shaped as
a cage adapted to be filled with a puree of bone matter forming the
graft.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0030] A better understanding of the invention will be facilitated
on reading the following description given merely by way of example
and with reference to the drawings, in which:
[0031] FIG. 1 is a basic schematic illustration of an inverted
shoulder prosthesis, implanted at a patient's shoulder;
[0032] FIG. 2 is a schematic elevation of an ancillary instrument
of a set of instruments according to the invention, used in order
to fit the prosthesis of FIG. 1;
[0033] FIG. 3 is a view similar to FIG. 2, illustrating another
ancillary instrument pertaining to the set of instruments, to be
applied to the patient's humerus after use of the ancillary
instrument of FIG. 2;
[0034] FIG. 4 is a schematic perspective view of a further
ancillary instrument pertaining to the set of instruments;
[0035] FIG. 5 is a view similar to FIG. 2, illustrating the humerus
after use of the ancillary instrument of FIGS. 3 and 4;
[0036] FIG. 6 is a schematic perspective view of another ancillary
instrument pertaining to the set of instruments;
[0037] FIG. 7 is a view similar to FIG. 2, illustrating the
application of the ancillary instrument of FIG. 6 to the humerus
after use of the ancillary instrument of FIG. 4;
[0038] FIGS. 8-12 show a second embodiment of a set of instruments
according to the invention,
[0039] FIGS. 8, 9, 11 and 12 being similar respective schematic
elevations of four ancillary instruments pertaining to this set and
used in succession, to fit the prosthesis from FIG. 1, whereas
[0040] FIG. 10 is a partial perspective view of the ancillary
instruments from FIG. 9, shown alone;
[0041] FIG. 13 is a basic schematic illustration of the glenoid
part of an inverted shoulder prosthesis according to the
invention;
[0042] FIG. 14 is a view similar to FIG. 13 of a variation of the
prosthesis according to the invention;
[0043] FIGS. 15-21 illustrate various uses of a graft to lateralize
the glenoid component of an inverted shoulder prosthesis according
to an embodiment of the present invention;
[0044] FIGS. 22-26 illustrate various uses of a graft to lateralize
the glenoid component of an anatomical shoulder prosthesis
according to an embodiment of the present invention;
[0045] FIGS. 27-29 illustrate various uses of a graft to lateralize
the glenoid component of an inverted shoulder prosthesis according
to an embodiment of the present invention; and
[0046] FIGS. 30A-30F illustrate a method and tool set for preparing
a graft in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0047] FIG. 1 shows a shoulder prosthesis 1 comprising a glenoid
component 10 and a humeral component 20, respectively implanted in
the scapula S and the humerus H of a patient's shoulder. The
glenoid components shown herein are illustrated schematically. The
method and apparatus of the various embodiments disclosed herein
may be used with a variety of other glenoid components, such as for
example those disclosed in U.S. Pat. Nos. 7,033,396; 6,953,478;
6,761,740; 6,626,946; 5,702,447 and U.S. Publication Nos.
2004/0220673; 2005/0278030; 2005/0278031; 2005/0278032;
2006/0020344, which are hereby incorporated by reference.
[0048] The glenoid component 10 comprises a head 11, also described
as a head structure, which has, on the side opposing the glenoid
surface G of the scapula S, a convex articular surface 11A, also
described as a face, of generally hemispherical shape and, on the
side turned toward the glenoid surface, an opposing face 11B. In
the example considered in the figures, this face 11B is generally
planar but, in non-illustrated variations, this face 11B can have a
more elaborate geometry, being, for example, substantially concave
or convex.
[0049] The glenoid component 10 also comprises an anchoring tail
12, also described as an anchor portion, which extends transversely
so as to protrude from the face 11B, in the direction opposing the
face 11A, and the free end part of which is securely anchored in
the glenoid surface G, thus joining the glenoid component to the
scapula S. In practice, in a manner not shown, the anchoring tail
12 can be provided, at its end turned toward the head 11, with a
base accommodated inside the head 11, being securely joined
thereto. In other words, more generally, the connection between the
tail 12 and the head 11 can assume a broad range of forms, such as
material continuity, respective wedging surfaces, attached
mechanical assembly structures, etc. Also by way of non-illustrated
variation, the tail 12 can be externally threaded or, generally,
have a surface state promoting the anchoring thereof.
[0050] Between the face 11B of the glenoid head 11 and the glenoid
surface G of the scapula S there is interposed a graft 2 having a
substantially cylindrical outer shape with a circular base, the
external diameter of which is substantially equal to that of the
head 11. The outer lateral face 2A of the graft 2 thus extends
substantially in the extension of the hemispherical face 11A. The
graft 2 has, on its side opposing the glenoid surface G, a
longitudinal end face or distal surface 2B covered by the face 11B
of the head 11 and, on its side directed toward the glenoid
surface, a longitudinal end face or medial surface 2C resting
against the glenoid surface G. Once the graft 2 fuses with the
glenoid surface G, the effective glenoid surface G is displaced
laterally outward to the distal surface 2B of the graft 2.
[0051] In the example considered in the figures, the longitudinal
end faces 2B and 2C are planar; this has proven to be an embodiment
that is simple to handle and easy to obtain, as will be referred to
hereinafter. However, in practice, these faces 2B and 2C can have
more elaborate geometries: on one side, the face 2B is provided to
be covered in a substantially complementary manner with the face
11B of the head 11, including in this face 11B the zones or the
structure for connecting to the tail 12, it being understood that,
as indicated hereinbefore, this face 11B can be generally concave,
convex or planar; on the opposing side, the face 2C is provided to
embrace the surface of the glenoid surface G, which has been
previously prepared for this purpose, so that the face 2C and the
glenoid surface G are substantially complementary and can equally
well be planar or curved.
[0052] The graft 2 can be a one-piece bone graft, a plurality of
random or pre-formed bone pieces, one or more layers of bone
material, a puree of bone substance, or combinations thereof. In
addition to the patient's bone, the graft 2 can also be formed from
an allograft, a xenograft, a synthetic material, a porous metal or
a combination thereof. The graft 2 can optionally be resorbable.
The graft 2 may be used alone or in combination with bone
replacements, bone fillers, bone cements and/or bone adhesives.
Various bone replacements, bone fillers, bone cements and bone
adhesives are disclosed in U.S. Pat. No. 6,692,563 (Zimmerman),
which is hereby incorporated by reference. Various additives can be
included in the graft 2, such as for example, bone growth agents or
pain inhibitors. In one embodiment, reinforcing fibers are added to
the puree of bone substance.
[0053] In some embodiments, the graft is formed of materials into
which native bone will grow to create a structure with properties
comparable to native bone, such as for example, a three-dimensional
porous matrix or scaffold. Examples of a porous matrix or scaffold
include a reticulated bioceramic framework, structured porous
tantalum, synthetic fiber mesh, and the like. Various porous
matrices and scaffoldings are disclosed in U.S. Pat. Nos.
4,479,271; 6,511,511; 6,605,117; 6,797,006; 6,902,584; and
7,250,550, which are hereby incorporated by reference.
[0054] The graft 2 can be made from a variety of synthetic
compounds, such as for example, polyglycolide, polylactides,
polycaprolactones, polytrimethylenecarbonates,
polyhydroxybutyrates, polyhydroxyvalerates, polydioxanones,
polyorthoesters, polycarbonates, polytyrosinecarbonates,
polyorthocarbonates, polyalkylene oxalates, polyalkylene
succinates, poly(malic acid), poly(maleic anhydride), polypeptides,
polydepsipeptides, polyvinylalcohol, polyesteramides, polyamides,
polyanhydrides, polyurethanes, polyphosphazenes,
polycyanoacrylates, polyfumarates, poly(amino acids), modified
polysaccharides (e.g., cellulose, starch, dextran, chitin,
chitosan, etc.), modified proteins (e.g., collagen, casein, fibrin,
etc.) and their copolymers, or combinations thereof. Other polymers
include polyglycolide, poly(L-lactide-co-glycolide),
poly(D,L-lactide-co-glycolide), poly(L-lactide), poly(D,L-lactide),
poly(L-lactide-co-D,L-lactide), polycaprolactone,
poly(L-lactide-co-caprolactone), poly(D,L-lactide-co-caprolactone)
polytrimethylenecarbonate,
poly(L-lactide-co-trimethylenecarbonate),
poly(D,L-lactide-co-trimethylen-ecarbonate), polydioxanone and
copolymers, and polymer blends thereof. Various methods of
manufacturing the bone graft from a synthetic compound can be found
in U.S. Pat. Nos. 6,767,928; 6,730,252; 6,541,022; 6,454,811, which
are hereby incorporated by reference. Optionally, before or during
the surgical procedure the graft 2 can be secured to the glenoid
component 10 using additional methods known in the art, such as for
example biocompatible adhesives, mechanical fasteners, or
combinations thereof.
[0055] The graft 2 can be made from a variety of metallic
solutions, such as for example, a highly porous metal having
interconnecting pores. In one embodiment, the porous metal is about
80% porous. The metal has a porosity giving it a mechanical and
physical structure similar to that of bone such that bone ingrowth
is promoted. The highly porous metal used to form the graft 2 has a
high strength-to-weight ratio and low stiffness and is capable of
withstanding physiologic loading and minimizing stress. The porous
metal may have, for example, a trabecular configuration. In one
embodiment, the porous metal may include growth factors to further
stimulate bone ingrowth. An example of a suitable graft is one
formed from tantalum and vapour deposition techniquies. An example
of a suitable commercially available porous metal includes but is
not limited to, "TRABECULAR METAL," available from Zimmer
Technology, Warsaw, Ind.
[0056] In some embodiments, the tail 12 passes straight through the
graft 2, in the longitudinal direction thereof. In other words, the
length of the tail 12 is much greater than that of the graft 2, so
that at least a substantial part of the tail 12 is anchored
securely in the native layer of the glenoid surface G. As described
in greater detail, in some embodiments the overall length of the
tail 12 is adjustable to accommodate a variety of thicknesses of
the graft 2 and/or geometry of the glenoid surface G.
[0057] In optional embodiments (not shown), the securing of the
graft 2 to the glenoid surface G can be reinforced by fasteners
additional to the tail 12, such as screws distributed around the
tail 12 and passing through the graft 2 over at least part of the
length thereof.
[0058] The humeral component 20 comprises a tail 21 for anchoring
in the medullary cavity M of the humerus H. At its upper end, the
tail 21 is provided with a head 22, also described as a humeral
head, having, on its side opposing the tail 21, a concave articular
face 22A in the form of a portion of a sphere, the radius of which
is substantially equal to that of the face 11A. References to a
humeral head should be interpreted to include a prepared or an
unprepared natural humeral head as well as synthetic, or prosthetic
humeral heads. When the prosthesis 1 is implanted, as shown in FIG.
1, the faces 11A and 22A are in mutual surface contact, thus
allowing the various desired shoulder articular movements.
[0059] Given the presence of the graft 2, the face 11A is remote
from the resected surface of the glenoid surface G in the sense
that, if the graft 2 were omitted, the face 11A would be directly
juxtaposed with the resected surface of the glenoid surface. Thus,
on account of the graft 2, the glenoid articular face 11A and,
accordingly, the humeral articular face 22A are laterally remote
from the glenoid surface G, limiting the risk of the lower portion
of the head 22 interfering with the bottom of the glenoid surface
G, (e.g., with the pillar P of the scapula S). Thus, lateralization
of the prosthesis 1 can be adjusted and modified based on the
thickness of the graft 2. As the thickness of the graft 2
increases, the amount of lateralization also increases. In
addition, it will be understood that, as a consequence resulting
from this lateralization desired within the scope of the invention,
the graft 2 acts as bone matter to make good any bone deficit in
the glenoid surface.
[0060] In practice, the glenoid component 10 can be of a broad
range of sizes, to which the graft 2 is adapted. Typically, the
head 11 is available in at least two different sizes, namely with
an external diameter of about 36 mm or about 42 mm, it being
understood that other sizes are conceivable. Similarly, the length
l of the graft 2 can have a broad range of values, distributed in
practice in a uniform sequence, in a manner adapted to the
morphology and/or to the pathology of the patient. The graft 2 can
thus have lengths of about 3, 6, 8 or 10 mm, whereas the tail 12
has a length of between about 15 and about 25 mm, possibly
greater.
[0061] A surgical method seeking to implant the shoulder prosthesis
1 of FIG. 1 will be described hereinafter, it being understood that
the prosthesis in question is merely a non-limiting illustrative
example of the method and the surgical instruments used to implant
this prosthesis. In other words, the method and the instruments
specified hereinafter can be used to implant shoulder prostheses of
a broad range of structures, of which, for example, the glenoid
and/or humeral components consist of a plurality of metallic,
plastic and/or ceramic-type parts joined together. Thus it is
possible, for example, to use a humeral component without an
anchoring tail.
[0062] FIGS. 2-12 illustrate various methods and instruments for
forming the graft 2 in situ. In a first stage of the operation,
once the soft parts of the shoulder have been removed using a
deltopectoral or supero-external approach, the shaft 31 of an
ancillary instrument 30 is introduced into the medullary cavity M
of the humerus H, passing straight through the upper epiphysis E of
the humerus H, as illustrated in FIG. 2. In order to do this, the
point of entry in the humeral epiphysis is determined beforehand by
radiograph analysis of the face and profile of the humerus H.
[0063] In its common part, the shaft 31 is secured, in particular
detachably, to a body 32 in the shape of an upwardly rounded bell.
The body 32 is generally arranged transversely to the shaft 31,
extending in length about a central geometrical axis 33. Projected
in a plane mediolateral to the patient and containing the
longitudinal axis of the shaft 31, as shown in FIG. 2, the central
geometrical axis 33 is inclined relative to the longitudinal axis
of the shaft at an angle .alpha. of between about 10 and about
70.degree., it being noted that, spatially, the two aforementioned
axes do not necessarily intersect but cross in a somewhat mutually
remote manner in an anteroposterior direction.
[0064] The body 32 has on its inside a concave surface 34, of which
the main center of curvature and the peak pertain substantially to
the central geometrical axis 33. The concave surface 34 is provided
to reproduce approximately the surface features of the upper
epiphysis of a normal anatomical humerus, it being understood that,
in practice, the surgeon has a range of a plurality of homothetic
ancillary instruments 30, the bodies 32 of which have respective
dimensions associated with the size and the state of the patient's
bones. On its outer face, the body 32 is provided with a protruding
tube 35 centered on the central geometrical axis 33 and opening
into the interior of the body 32, on its inner surface 34.
[0065] The shaft 31 is inserted into the medullary cavity M of the
humerus H until contact is established between the inner surface 34
and the humeral epiphysis E, the body 32 then covering the
epiphysis E in the manner of a cap. Then, advantageously, the shaft
31 is driven in rotation about itself, over a short course, in
order to allow for the retroversion of the humerus H. In a manner
known to those of skill in the art, the shaft 31 is provided, in
its proximal end part, with diametral through-orifices 36 angularly
offset from one another about the longitudinal axis of the shaft 31
and, as a function of the retroversion of the patient determined by
the surgeon, an elongate rod (not shown) is introduced into one of
these orifices in order effectively to display the retained
direction of retroversion, so that the shaft 31 is rotated on
itself until this retroversion rod is aligned with the patient's
forearm.
[0066] A guide pin 40, at the pointed distal end 41, is then
introduced into the tube 35, from the free end thereof, and is
inserted into the humeral epiphysis E over a substantial depth, as
indicated by arrow 42 in FIG. 2, until its point pierces and passes
at least partially through the outer cortex of the humerus H. It
will be understood that the ancillary instrument 30 allows the
guide pin 40 to be inserted in a suitable direction relative to the
humerus H, the tube 35 acting as a guide for introducing and
feeding through the pin. In order to prevent interference between
the guide pin 40 and the shaft 31, when the guide pin 40 passes
through the central zone of the humerus H, the corresponding common
part 37 of the shaft 31 advantageously tapers: the part 37 of the
shaft 31 thus has a smaller cross-section than the proximal and
distal end parts forming the remainder of the shaft 31.
[0067] Once the guide pin 40 has reached an insertion depth in, or
even through, the humerus H sufficient securely to anchor it, the
ancillary instrument 30 is withdrawn, without removing the guide
pin 40. The humerus H is then in the state illustrated by solid
lines in FIG. 3.
[0068] In a variation, when carrying out the first stage of the
operation, the guide pin 40 is inserted in the humerus H without
being guided, i.e. without using the ancillary instrument 30.
[0069] In a second stage, the surgeon will resect the end of the
humeral epiphysis E using an ancillary instrument 50 illustrated in
FIG. 3. This ancillary instrument 50 comprises a tubular body 51,
the internal central bore in which has a diameter equal to the
external diameter of the guide pin 40. At the distal end of the
body 51, the ancillary instrument 50 comprises a planar cutter 52,
extending in a plane substantially perpendicular to the
longitudinal axis of the body 51. In the distal projection of the
cutter 52 and in a manner centered on the longitudinal axis of the
body 51, the ancillary instrument 50 further comprises a terminal
drill 53 internally delimiting a central bore communicating with
the bore in the body 51. The external diameter of the drill 53 is
provided so as to be equal to the external diameter of the
anchoring tail 12 of the glenoid component 10 to be implanted, for
reasons which will become apparent hereinafter.
[0070] The surgeon threads the ancillary instrument 50 around the
guide pin 40 by introducing it by the terminal drill 53 thereof, as
indicated by arrow 54 in FIG. 3. When this drill reaches the end of
the epiphysis E, it drills the bone matter so as to form a
cylindrical recess E.sub.1 centered about the guide pin 40 and
indicated by broken lines in FIG. 3. Similarly, as the ancillary
instrument 50 moves downward along the guide pin 40, the cutter 52
gradually resects the end of the humeral epiphysis E, over a depth
of a few millimeters, until there is obtained a cutting plane
E.sub.2 perpendicular to the guide pin 40, also indicated by broken
lines in FIG. 3.
[0071] In a third stage, once the ancillary instrument 50 has been
removed from the guide pin 40, the surgeon will cut the humeral
epiphysis E in a manner centered on the guide pin 40, i.e. he will
shape the bone matter forming this epiphysis E into a cylinder
E.sub.3 having a center axis E.sub.X-X corresponding to the axis
33, as illustrated in FIG. 5. For this purpose, the surgeon uses an
ancillary instrument 60 illustrated in FIG. 4. The ancillary
instrument 60 comprises a central rod 61, bored internally in a
manner complementary to the guide pin 40 and having an external
diameter equal to that of the drill 53. The rod 61 carries, in its
common part, a crown saw 62 which is of annular shape centered on
the rod 61 and the distal end edge of which has teeth 63.
[0072] The rod 61 of the ancillary instrument 60 is slipped around
the guide pin 40, which is left in place in the humeral epiphysis
E, until its distal end is received in a complementary manner in
the recess E.sub.1. In doing this, the saw 62 gradually cuts out
the bone matter from the epiphysis E so as to obtain the bone
cylinder E.sub.3, it being noted that a corresponding part of the
recess E.sub.1 passes through the entire length of said bone
cylinder. The length of the cylinder E.sub.3 thus obtained, i.e.
its dimension along its axis E.sub.X-X, is determined by the depth
of action of the saw 62, wherein this depth can easily be marked
along the rod 61, in particular by markings.
[0073] Once the ancillary instrument 60 has been removed, the
humerus H is in the state illustrated in FIG. 5.
[0074] In a fourth stage, the surgeon will remove the cylinder of
bone matter E.sub.3 from the humerus H using a cutting ancillary
instrument 70 illustrated in FIGS. 6 and 7. This ancillary
instrument 70 comprises a tubular block 71, the internal diameter
of which is equal to that of the saw 62. At its distal end, the
block 71 forms a protruding outer edge 72 in which there is
delimited a transverse slot 73 opening into the internal volume of
the block. At its proximal end, the block 71 is closed by a base
wall 74, from the central zone of which there protrudes, inside the
block, a centering stud 75, the external diameter of which is equal
to that of the drill 53.
[0075] After having removed the guide pin 40, the ancillary
instrument 70 is slipped around the humeral cylinder E.sub.3, as
indicated by arrow 76 in FIG. 7. The cylinder E.sub.3 is received
in a complementary manner in the block 71 until the edge 72 rests
against the bone surface surrounding the base of the cylinder
E.sub.3. A planar saw blade (not shown) is then introduced from
outside into the slot 73 in order to cut the base of the cylinder
E.sub.3 over a cutting plane E.sub.4 substantially perpendicular to
the axis E.sub.X-X and indicated by broken lines in FIG. 7. During
sawing, most of the cylinder E.sub.3 is protected by the block 71
and the base wall 74, it being noted that the stud 75 is
accommodated in a complementary manner in the upper end part of the
central recess E.sub.1.
[0076] Once the ancillary instrument 70 has been removed, the
surgeon recovers the cylinder of bone matter E.sub.3 thus separated
from the humerus H.
[0077] In a non-illustrated variation, the slot 73 can be provided
so as to be inclined relative to the longitudinal direction of the
block 71 so that, in contrast to the cylinder E.sub.3 described
hereinbefore, the bone cylinder thus obtained has longitudinal end
faces inclined relative to one another. The graft 2 is thus able to
make good the wear to a peripheral portion of the glenoid surface
G, it being noted that the inclination of the slot 73 is
advantageously adjustable as a function of the wear noted by the
surgeon during the operation.
[0078] Before describing the following stage of the operation,
namely the fifth stage, FIGS. 8 to 12, which illustrate a set of
instruments forming a variation of the unit comprising the
ancillary instrument 30, 50, 60 and 70 described hitherto, will now
be considered.
[0079] Thus, FIG. 8 shows an ancillary instrument 130 as a
variation of the ancillary instrument 30 from FIG. 2. The ancillary
instrument 130 comprises a distal body 132 which is functionally
similar to the body 32 of the ancillary instrument 30. In
particular, the body 132 is designed to cover the upper humeral
epiphysis E in the manner of a cap. Unlike the body 32 of the
ancillary instrument 30, the body 132 is perforated, in particular
to give the surgeon a better view of the humeral epiphysis when
positioning the body 132. Like the body 32 of the ancillary
instrument 30, the body 132 is provided with a proximal tube 135
projecting from its external face and centered on the axis 133
around which the body 132 extends.
[0080] The ancillary instrument 130 allows the guide pin 40 to be
inserted in the humeral epiphysis E so as to be close-fitted
relative to the humerus H, as indicated by the arrow 142 in FIG.
8.
[0081] As a variation of both the ancillary instrument 50 and the
ancillary instrument 60 shown in FIGS. 3 and 4, an ancillary
instrument 160 is shown in FIGS. 9 and 10. The ancillary instrument
160 comprises an elongate shaft 161 provided, at its distal end,
with a crown saw 162 of annular shape centered on the shaft 161 and
of which the distal end edge has teeth 163. The shaft 161 has an
internal bore throughout its length so that it can be slipped, in a
close-fitting and coaxial manner, around the guide pin 40 which is
left in position in the humeral epiphysis E, as indicated by the
arrow 164 in FIG. 9. Unlike the saw 62 of the ancillary instrument
60, the saw 162 has perforations in its lateral wall and comprises
a base wall 165 which extends perpendicularly to the longitudinal
direction of the shaft 161 and of which the distal face forms a
planar reamer 166.
[0082] Hence, when the ancillary instrument 160 is slipped round
the guide pin 40, the teeth 163 of the saw 162 gradually cut out
the bone matter of the humeral epiphysis E so as to obtain the bone
cylinder E.sub.3. Once the entire height of the saw 162 has thus
been introduced into the epiphysis, the reamer 166 begins to cut
the upper end of this epiphysis and thus progressively resects this
end until the cutting plane E.sub.2 is obtained.
[0083] Once the ancillary instrument 160 has been released, the
humerus H is in the state shown in FIG. 11.
[0084] The surgeon then uses a drilling ancillary instrument 167
comprising a bored shaft 168 of which the distal end is provided
with a drill 153. By slipping the shaft 168 around the guide pin
40, as indicated by the arrow 169 in FIG. 11, the surgeon, by the
action of the drill 153, digs the central part of the cylinder of
bone matter E.sub.3 round the guide pin 40 so as to form the recess
E.sub.1, centered on the axis E.sub.x-x of the cylinder E.sub.3, as
indicated in broken lines in FIG. 12, in which the ancillary
instrument 168 has been released.
[0085] In practice, the drilling ancillary instrument 167 can also
be used after a variation of the ancillary instrument 50, depleted
of the drill 53, has been used and/or after a variation of the
ancillary instrument 60, of which the rod 61 does not project on
the distal side of the base wall of the saw 62 has been used.
[0086] As a variation of the ancillary instrument 70 shown in FIGS.
6 and 7, FIG. 12 shows an ancillary instrument 170. The ancillary
instrument 170 comprises an annular body 171 equipped at a point of
its periphery with a proximal handling shaft 176. The annular body
171 is designed to be mounted on the humeral epiphysis E while
surrounding the entire portion of the epiphysis in which the
cylinder of bone matter E.sub.3, previously cut out by the
ancillary instrument 160, is delimited. On its distal side, the
body 171 delimits a surface 173 for application and guidance of a
bone cutting instrument, not shown, such as a saw blade or the
like.
[0087] Hence, by manipulating the shaft 176, the surgeon positions
the annular body 171 around the humeral epiphysis E so as to
position the guide surface 173 in a suitable manner relative to the
cylinder of bone matter E.sub.3. The surgeon then applies the
cutting instrument against this surface 173 in a guided manner in
order to cut the base of the cylinder E.sub.3 over the cutting
plane E.sub.4 and release this cylinder from the humerus H.
[0088] Advantageously, the guide surface 173 forms an angle of
approximately 155 degrees with the longitudinal direction of the
shaft 176, and this allows the ancillary instrument 170 also to be
used to prepare the implantation of the humeral component 20 at a
later stage, by positioning the shaft 176 in such a way that its
longitudinal direction is substantially aligned with the
longitudinal direction of the humerus H, as illustrated in FIG.
12.
[0089] In a fifth stage, the cylinder of bone matter E.sub.3 is
used to form the graft 2 described hereinbefore. In order to do
this, this cylinder is fitted on the glenoid surface G. The glenoid
surface G is previously prepared for this purpose, being opened up
and, if necessary, resected. The glenoid component 10 is then
implanted in the configuration described hereinbefore with
reference to FIG. 1. It will be understood that the anchoring tail
12 is introduced coaxially, in a substantially close-fitting
manner, into the central recess E.sub.1 in the cylinder
E.sub.3.
[0090] If the longitudinal end faces of the bone cylinder have been
formed so as to be inclined relative to each other, it will be
understood that the interposing of this cylinder, as the graft,
between the glenoid component 10 and the glenoid surface G allows
inclination, in particular downward inclination, of the glenoid
articular face 11A.
[0091] More generally, it will be understood that the dimensions
desired by the surgeon for the graft 2, in particular as a function
of the size of the glenoid component 10, determine the dimensions
of the ancillary instruments 50, 60 and 70 or the ancillary
instruments 160, 168 and 170 used to take the bone cylinder E.sub.3
from the humeral epiphysis E. In particular, the internal diameter
of the saw 62 or 162 determines the external diameter of the graft
2. Similarly, the depth of action of this saw determines the
length/of the graft while at the same time allowing for any
adjustment in length resulting from the positioning of the sawing
slot 73 or the guide surface 173.
[0092] Furthermore, the geometry desired for the longitudinal end
faces 2B and 2C of the graft 2 directly conditions the embodiment
of the resection ancillary instrument 50 and cutting ancillary
instrument 70 or the ancillary instrument 160 and 170, in the sense
that the parts of these ancillary instruments that determine the
incision profile of the bone are shaped to form an appropriate
incision in the humeral epiphysis. Optionally, these ancillary
instruments 50 and 70 can be associated with one or more ancillary
instrument for resurfacing the longitudinal end faces of the
removed cylinder E.sub.3.
[0093] In practice, the surgeon also takes account of the state of
the cancellous bone matter forming the epiphysis E in order, if
necessary, to remove the graft with as healthy a constitution as
possible. For this purpose ancillary instrument for gripping and
storing the graft 2 after it has been released from the humerus H
can optionally be provided, in order to limit the risks of damaging
the graft.
[0094] Furthermore, in non-illustrated variations, the graft 2 can
have volume forms other than a cylinder as in the figures, provided
that the volume of bone matter forming the graft 2 has a shape
generally centered about a longitudinal axis of the type of the
axis E.sub.X-X, while at the same time defining a lateral face and
longitudinal end faces of the type of the faces 2A, 2B and 2C. For
example, the graft 2 can thus be truncated in shape, having a
longitudinal axis E.sub.X-X; in this case, the inner surface of the
crown saw 62 or 162 is, for example, provided so as to be
truncated.
[0095] Optionally, the graft 2 can be protected laterally by a
reinforcing structure, such as for example ring 80 shown in FIG.
13. In practice, the ring 80 is configured to surround in an
appropriate manner the lateral face 2A of the graft 2, over the
entire length of this graft. The ring 80 is thus, in conjunction
with the graft 2, interposed between the glenoid component 10 and
the glenoid surface G. It will be understood that the ring 80 can,
for example, be used if the graft 2 has, at least over a part of
its length, an external diameter less than that of the glenoid head
11, the ring thus compensating for the difference in diameter.
[0096] If the ring 80 is implanted in conjunction with the graft 2,
it protects the lateral face 2A of the graft 2 and forms a support
for at least a part of the face 11B of the glenoid component 10,
thus limiting the stresses applied to the graft 2. Advantageously,
the ring 80 is covered with hydroxyapatite or, more generally, has
a porous or honeycomb surface state allowing improved bone adhesion
and rehabilitation of the ring 80 to the graft 2 and to the
resected surface part of the glenoid surface G that is not covered
by the graft 2. In one embodiment, the ring 80 is attached to the
glenoid component 10.
[0097] In practice, it will be understood that the inner surface of
the ring 80 is advantageously complementary with the face 2A of the
graft 2, whereas its outer face can have advantageous optional
configurations. The outer surface can thus be provided so as to be
truncated and diverged toward the glenoid surface G, so holes
passing through the ring 80 in respective directions substantially
perpendicular to the outer surface thereof are able to receive
screws or the like in order to reinforce the securing of the graft
2 to the glenoid surface G. Similarly, the bottom portion of the
ring 80 can be provided so as to be less thick than the remainder
of the ring so as not subsequently to disturb the humeral component
20 during adduction movements on the part of the patient.
[0098] In a variation of the fitting method, rather than delivering
a one-piece bone volume such as the cylinder E.sub.3, in the upper
humeral epiphysis E, the graft 2 can consist of a puree of bone
substance. This substance is taken from the spongy bone zones of
the humeral epiphysis, in particular when preparing the humerus H
for the fitting of the humeral implant. In practice, in order to
contain this puree of bone substance during implantation of the
glenoid component 10, a reinforcing structure, such as for example
a lattice 90 shaped as a cage 92 for receiving this puree will
advantageously be used, as shown in FIG. 14. The cage 92 is
designed to be interposed between the glenoid component 10 and the
previously prepared glenoid surface G, according to an arrangement
similar to the one-piece graft illustrated in FIG. 1. In
particular, the cage 92 has, for example, a generally cylindrical
shape of which the external diameter corresponds to that of the
glenoid head 11 and of which the length corresponds to the
aforementioned length l.
[0099] The lattice 90 forming the cage 92 allows exchanges of
biological fluids between the puree of bone substance with which
the cage is filled and the surrounding tissues of the patient. The
cage 92 thus prevents necrosis of the puree of bone substance while
mechanically protecting it. In particular the cage 92 absorbs a
proportion, or even the majority, of the stresses applied to the
graft 2 consisting of the puree of bone substances by forming, in
the region of its lateral end walls 92A and 92B, supports for the
face 11B of the glenoid component 10 and the previously prepared
surface of the glenoid surface G respectively. The bone substance
preferably chemically bonds with the glenoid surface G through the
lattice 90. In effect, the glenoid surface G is extended laterally
outward to engage with the face 11B of the glenoid component
10.
[0100] In another embodiment, the cage 92 is constructed from a
porous matrix or scaffold, without the puree of bone substance. The
cage 92 can be, for example, reticulated bioceramic framework,
structured porous tantalum, synthetic fiber mesh, and the like. The
native bone of the glenoid surface G grows into the porous matrix
or scaffold to create a graft with structure properties comparable
to native bone. The cage 92 is alternately made of a
slow-absorbing, biologically benign material, such as
Poly-4-hydroxybutyrate (a.k.a. Tephaflex.TM.), poly(urethane urea)
(Artelon.TM.), surgical silk, or other materials, known to the art,
having similar characteristics, such as disclosed in U.S. Patent
Publication No. 2007/0198087, entitled Method and Device for
Rotator Cuff Repair, filed Feb. 5, 2007 and U.S. Patent Publication
No. 2007/0276509, entitled Tissue Scaffold, filed Aug. 9, 2007, the
entire disclosures of which are incorporated by reference. Other
less preferred embodiments employ non-absorbable materials such as
PTFE, Polypropylene, Nylon, or other biocompatible, inert materials
known to the art.
[0101] Before or after implanting of the glenoid component 10, the
humeral component 20 is implanted in the humerus H, advantageously
using ancillary instrument (not shown), the handling of which is
marked by the end part of the recess E.sub.1 remaining in the
humeral epiphysis E after removal of the bone volume such as the
cylinder E.sub.3. If the surgical actions applied to the humerus H
for implanting the component 20 by way of the recess E.sub.1 are
dispensed with and these actions are therefore generally
independent of those applied to the humerus for taking the graft 2,
the ancillary instrument 30 can be simplified, as it is in this
case no longer necessary to take account of the retroversion of the
patient's forearm in order to insert the guide pin 40. The shaft 31
may in this case assume the form of an intramedullary humeral
rod.
[0102] According to a variation of the fitting method, the graft 2,
whether in the form of a one-piece bone volume or of a puree of
bone substance, is not taken from the humeral epiphysis E but
rather is taken from another of the patient's bones, in particular
from his ilium, or consists of an allograft, a graft of synthetic
origin or a graft of metallic origin, it being understood that the
dimensions of this synthetic graft are provided so as to be
appropriate for the glenoid component 10 to be implanted, as stated
hereinbefore for the removed cylinder E.sub.3 or cone frustum.
Obviously, the protection ring 80 and the cage 92 described
hereinbefore can be used in conjunction with a graft of this type
of alternative origin.
[0103] FIG. 15 is a schematic illustration of a glenoid component
200 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. The
glenoid component 200 includes a recess 202 that substantially
receives the graft 204. The recess 202 acts as a reinforcing
structure that protects the graft 204 laterally, similar to the
ring 80 in the embodiment of FIG. 13. Consequently, the graft 204
can be a one-piece bone volume, a puree of bone substance or formed
from a synthetic or metallic material. In an embodiment where the
graft 204 is a puree of bone substance, reinforcing fibers 279 are
optionally added to the mixture. In the illustrated embodiment,
lower portion 206 of the convex articular surface 208 extends
beyond the pillar of the scapula S to minimize interference with
the humeral prosthetic portion. The radius of curvature of convex
articular surface 208 is preferably selected so the center of
rotation 214 around the glenoid component 200 is preferably in
plane 210 comprising a distal surface 212 of the graft 204 or
between the plane 210 and the glenoid surface G. Once the graft 204
has fused with the glenoid surface G, the distal surface 212 of the
graft 204 becomes the effective glenoid surface.
[0104] FIG. 16 is a schematic illustration of a glenoid component
220 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. A
reinforcing structure 222 extends over at least a portion of the
graft 224. The reinforcing structure 222 can be rigid or flexible.
In one embodiment, the reinforcing structure 222 is constructed
from a mesh material made from metal, synthetics, ceramics, or a
combination thereof. Consequently, the graft 224 can be a one-piece
bone volume, a puree of bone substance or formed from a synthetic
or metallic material. Screws 226 optionally secure the reinforcing
structure 222 and/or graft 224 to the glenoid surface G.
[0105] The glenoid component 220 includes a recess 230 that engages
with distal surface 232 of the reinforcing structure 222. An anchor
234 optionally extends through the reinforcing structure 222 and
graft 224 to further secure the glenoid component 220 to the
scapula S. In the illustrated embodiment, the anchor 234 includes a
pointed tip 236 to facilitate insertion into the glenoid surface G.
The radius of curvature 228 of convex articular surface 235 is
preferably selected such that the center of rotation 233 of the
glenoid component 220 is preferably either in or behind plane 237
comprising a distal surface 239 of the graft 224. Once the graft
224 has fused with the glenoid surface G, the distal surface 239 of
the graft 224 becomes the effective glenoid surface.
[0106] FIG. 17 is a schematic illustration of a glenoid component
240 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. A
graft 242 is formed with a distal recess 244. An anchor 246 extends
through the graft 242 into the glenoid surface G so that base plate
248 is positioned in the distal recess 244. A tension member 250 is
optionally positioned in a center bore 252 of the anchor 246 to
retain the base plate 248 against the glenoid surface G. A variety
of glenoid components 240 can then be attached to the base plate
248 using a variety of attachment mechanisms. In one embodiment,
the graft 242 is surrounded by reinforcing structure 257, such as
for example a metal or synthetic mesh material. The radius of
curvature of convex articular surface 258 is preferably selected so
the center of rotation 259 around the glenoid component 240 is
preferably in or behind a plane 254 comprising a distal surface 256
of the graft 242. Once the graft 242 has fused with the glenoid
surface G, the distal surface 256 of the graft 242 becomes the
effective glenoid surface.
[0107] FIG. 18 is a schematic illustration of a glenoid component
260 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. A
graft 262 is secured to the glenoid surface G using base plate 264
and anchor 266. The glenoid component 260 includes a first recess
268 sized to engage with the base plate 264 and a second recess 270
so that extensions 272 of the convex articular surface 271 extend
onto a portion of the scapula S. The extensions 272 can optionally
be flexible or semi-flexible to facilitate implantation. In one
embodiment, the extensions 272 are attached to the scapula S using
adhesives, fasteners, and the like. The graft 262 can be a
one-piece bone volume, a puree of bone substance or formed from a
synthetic or metallic material. The radius of curvature of convex
articular surface 271 is preferably selected such that the center
of rotation 278 around the glenoid component 260 is preferably in
or behind a plane 274 comprising a distal surface 276 of the bone
graft 262.
[0108] FIG. 19 is a schematic illustration of a glenoid component
280 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. A
bone graft 282 is located between the glenoid surface G and the
opposing surface 284 of the glenoid component 280. In the
illustrated embodiment, the bone graft 282 is two or more layers
282a, 282b of bone graft material. A tension member 286 is
positioned in center bore 288 to retain the glenoid component 280
against the glenoid surface G. The radius of curvature of convex
articular surface 290 is preferably selected so the center of
rotation 296 is in or behind plane 292 comprising distal surface
294 of the bone graft 282.
[0109] FIG. 20 is a schematic illustration of a glenoid component
300 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. An
adjustable anchor portion, also described as an anchor structure or
tail portion, of the glenoid component 300 includes reinforcing
structure 302, which is attached to the boney structure forming the
glenoid surface G using fasteners 304. Side walls 303 of the
reinforcing structure 302 support a bone graft 310 by engaging an
outer lateral face 311 of the bone graft 310. The reinforcing
structure 302 preferably has a plurality of holes or perforations
306 to facility bone in-growth.
[0110] The adjustable anchor portion also includes an opposite
reinforcing structure 308 that extends over the reinforcing
structure 302 and bone graft 310 and restricts lateral movement of
the bone graft 310. Thus, the adjustable anchor portion is formed
of two, opposing portions--the first and second reinforcing
structures 304, 308. In the illustrated embodiment, the opposite
reinforcing structure 308 telescopically engages with the
reinforcing structure 302 to adjust an overall length of the
reinforcing structure 308. The bone graft 310 has a distal face 312
and a medial face 313 and defines a thickness between the distal
and medial faces 312, 313. The bone graft 310 can be a one-piece
bone volume, a puree of bone substance, or any of the other
materials previously described. The opposite reinforcing structure
308 optionally includes a plurality of holes 307 to facilitate bone
in-growth.
[0111] In some embodiments, the glenoid component 300 includes an
articulation surface 315A and an engagement surface 315B that is
attached to distal surface 312 of the opposing reinforcing
structure 308. In the illustrated embodiment, the glenoid component
300 is mounted to the opposing reinforcing structure 308
off-center. The opposing reinforcing structure 308 preferably has a
plurality of mounting features that permit the surgeon to locate
the glenoid component 300 in a variety of locations. The radius of
curvature of convex articular surface 314 is preferably selected so
the center of rotation 319 is in or behind plane 316 comprising
distal surface 318 of the bone graft 310. In another embodiment,
the center of rotation is close to the plane 316.
[0112] FIGS. 20A and 20B show additional glenoid components that
include adjustable length tails, or anchoring structures for use
with grafts having a variety of thicknesses, according to
embodiments of the present invention. For example, in some
embodiments, a surgeon or other user selects a desired bone graft
thickness and adjusts the overall length of an anchoring portion of
the glenoid component for use with that graft thickness. By
adjusting the overall length of the anchoring structures, the
glenoid components are better able to facilitate lateralization of
the center of rotation of the glenoid component with a secure
affixation into the boney structure forming the glenoid, for
example, as well as additional or alternative advantages. In some
embodiments, the bone graft is at least 7 mm thick, at least 10 mm
thick, or from about 7 mm thick to about 10 mm thick, and the
anchor portion is adjustable to at least 20 mm in length, at least
25 mm in length, or from about 20 mm in length to about 25 mm in
length, although other dimensions are contemplated.
[0113] FIG. 20A shows a glenoid component 300A of an inverted
shoulder prosthesis, according to an embodiment of the present
invention. The glenoid component 300A includes a head 301A, also
described as a head structure, which has a convex articular surface
302A of generally hemispherical shape and an opposing, engagement
face 303A. The convex articular surface is adapted for engagement
with a humeral head (e.g., a prosthetic humeral head or a natural
humeral head that has been formed to define a complementary,
concave humeral articular surface). In some embodiments, the
opposing face 303A is generally planar although different
configurations (e.g., concave or convex configurations) are
contemplated. Although an inverted shoulder prosthesis
configuration is shown, in other embodiments the glenoid component
300A is configured as a standard shoulder prosthesis with the
articular surface 301A being substantially concave, for
example.
[0114] As shown, the glenoid component 300A also includes an
anchoring tail 304A, also described as an anchoring portion or
anchoring structure, that extends transversely from the engagement
face 303A and is adapted to be anchored in the glenoid surface G
(FIG. 1) to secure the glenoid component to the scapula S (FIG. 1).
In some embodiments, the anchoring tail 304A is provided with a
base (not shown) adapted to be received inside the head 301A and
secured thereto (e.g., via a press fit, complementary threads,
adhesives, or other fastening means). In different terms, the
connection between the tail 304A and the head 301A optionally
includes material continuity (i.e., formation of a single piece of
material, also described as a monolithic structure), respective
wedging surfaces (e.g., a press fit), mechanical assembly
structures (e.g., threading), and others.
[0115] As shown, the anchoring tail 304A defines an overall length
and includes a first portion 305A having an inner lumen 306A, a
second portion 307A, and a lock member 308A. The first portion 305A
optionally has a substantially circular cross-section, although
non-circular cross-sections (e.g., hexagonal or square), are
contemplated. As described, the tail 304A is configured such that a
user is able to telescope the second portion 307A in and out of the
first portion 305A in order to adjust the overall length of the
anchoring tail 304A. In some embodiments, the second portion 307A
includes a conical threadform or a buttress threadform.
[0116] The inner lumen 306A of the first portion 305A optionally
includes female threading (not shown). The second portion 307A is
adapted to telescopically fit within the inner lumen 306A of the
first portion 305A, the second portion 306A having male threading
309A according to some embodiments. The second portion 307A is
optionally substantially cylindrical with a circular transverse
cross-section, although other cross sections (e.g., hexagonal or
square) are contemplated. The lock member 308A is optionally formed
similar to a nut, with flats or other surface features. The overall
length of the tail 304A is adjusted by rotating the second member
within the first member to the desired overall length. The overall
length is optionally locked by tightening the lock member 308 to
help ensure the anchoring tail 304A remains at the desired length
and does not back or forward rotate to a different overall
length.
[0117] In some embodiments, a bone graft (not shown) such as those
previously described, is received by the tail 304A, the bone graft
optionally including a central aperture or other feature that fits
over the tail that restricts lateral movement of the bone graft and
secures the bone graft to the tail 304A, where the tail 304A
receives the bone graft with a medial surface of the bone graft
engaged with the engagement face 303A. In some embodiments, the
bone graft is first received against the engagement face 303A and
then the tail 304A is secured to the head 301A thereby securing the
bone graft to the head 301A. In some embodiments, the bone graft is
received over the first portion 305A of the tail 304A and then the
second portion 306A is secured to the first portion 305A of the
tail 304A.
[0118] FIG. 20B shows a glenoid component 300B of an inverted
shoulder prosthesis, according to some other embodiments. The
glenoid component 300B includes a head 301B which has a convex
articular surface 302B of generally hemispherical shape and an
opposing face 303B. In some embodiments, the opposing face 303B is
generally planar although different configurations (e.g., concave
or convex configurations) are contemplated. Although an inverted
shoulder prosthesis configuration is shown, in other embodiments
the glenoid component 300B is configured as a standard shoulder
prosthesis with the articular surface 302B being substantially
concave, for example.
[0119] As shown, the glenoid component 300B also includes an
anchoring tail 304B that extends transversely from the face 302B
and is adapted to be anchored in the glenoid surface G (FIG. 1) to
secure the glenoid component to the scapula S (FIG. 1). In some
embodiments, the anchoring tail 304B is provided with a base (not
shown) adapted to be received inside the head 301B and secured
thereto (e.g., via a press fit, complementary threads, adhesives,
or other fastening means). In different terms, the connection
between the tail 304B and the head 301B optionally includes
material continuity (i.e., formation of a single piece of material,
also described as a monolithic structure), respective wedging
surfaces (e.g., a press fit), mechanical assembly structures (e.g.,
threading), and others.
[0120] As shown, the anchoring tail 304B defines an overall length
and includes a first portion 305B having an inner lumen 306B and a
second portion 307B. The second portion 307B is optionally
interchanged with a similar component having a substantially
different configuration, such as a different length. For example, a
third portion 308B is shown which may be substituted for the second
portion 307B. Additional components, of different lengths, widths,
cross-sections, or other alternate configurations that are adapted
to be secured to the first portion 305B are also available
according to some embodiments.
[0121] The first portion 305B optionally has a substantially
circular cross-section, although non-circular cross-sections (e.g.,
hexagonal or square), are contemplated. As alluded to in the
foregoing description, the tail 304B is configured such that a user
is able to select between a plurality of extensions (e.g., between
second and third portions 307B, 308B) in order to adjust the
overall length of the anchoring tail 304B. The inner lumen 306B of
the first portion 305B optionally includes female threading (not
shown). In some other embodiments, the first portion 305B includes
male threading for mating with female threading on the second
portion 307B and/or third portion 307C.
[0122] In some embodiments, the second portion 307B has a narrowed
region 309B with male threading adapted to form a complementary fit
with the female threading of the first portion 305B. The second
portion 307B is optionally substantially cylindrical with a
circular transverse cross-section, although other cross sections
(e.g., hexagonal or square) are contemplated. As shown, the second
portion 307B has a length that is substantially longer than that of
the third portion 308B. Thus, a user desiring to adjust the overall
length of the anchoring tail 304B is able to not attach any
additional component to the first portion 305B (i.e., utilize the
non-extended length of the anchoring tail 304B), or select between
securing one of a plurality of additional components of different
lengths (e.g., the second and third portions 307B, 308B) to the
first portion 305B to extend the overall length of the anchoring
tail 304B.
[0123] In some embodiments, a bone graft 309B such as those
previously described, is received by the tail 304B, the bone graft
optionally including a central aperture or other feature that fits
over the tail that restricts lateral movement of the bone graft and
secures the bone graft to the tail 304B. As shown in FIG. 20B, the
bone graft 309B has a central aperture 310B and defines a medial
face 311B, a distal face 312B, and a thickness between the medial
and distal faces 311B, 312B. As shown, the tail 304B receives the
bone graft 309B with the medial surface 311B engaged with the
engagement face 303B. As shown, the aperture 310B and the tail 304B
have substantially complementary transverse cross-sections,
although other configurations are contemplated.
[0124] In some embodiments, the bone graft 309B is first received
against the engagement face 303B and then the tail 304B is secured
to the head 301B thereby securing the bone graft to the head 301B.
In some embodiments, the bone graft 309B is received over the first
portion 305B of the tail 304B and then the second portion 306B is
secured to the first portion 305B of the tail 304B.
[0125] FIG. 21 is a schematic illustration of a glenoid component
320 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. The
glenoid surface G is resected at an angle 322 with respect to the
medial line M of the patient. In order to compensate, the bone
graft 324 is formed with non-parallel faces 326, 328. In the
illustrated embodiment, the bone graft 324 is secured to the
glenoid surface G using fasteners 330, although any of the
structures disclosed herein could be used. The radius of curvature
of convex articular surface 332 is preferably selected so the
center of rotation 338 is in or behind plane 334 comprising distal
surface 336 of the bone graft 324.
[0126] FIG. 22 is a schematic illustration of a glenoid component
340 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. The
exposed surface 342 of the glenoid surface G is non-planar. In
order to compensate, the bone graft 344 is preferably formed with a
complementary shaped surface 346. In the illustrated embodiment,
opposing face 348 of the glenoid component 340 also is non-planar.
Consequently, distal surface 350 of the bone graft 344 is also
preferably formed with a complementary shape. The non-planar
surfaces 346, 348 provide structural advantages for some
applications.
[0127] In the illustrated embodiment, the glenoid component 340 is
secured to glenoid surface G using a plurality of fasteners 352.
Although distal surface 354 of the glenoid component 340 is
illustrated as planar it can be configured for with either a convex
or concave articular surface, depending on the application.
[0128] FIG. 23 is a schematic illustration of a glenoid component
360 of an anatomical shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. An
opposing face 362 of the glenoid component 360 is non-planar. In
order to compensate, distal surface 364 of the bone graft 366 is
preferably formed with a complementary shape. In the illustrated
embodiment, the glenoid component 360 is secured to glenoid surface
G using anchor 368, although any of the securing structures
disclosed herein may be used. A distal surface 370 of the glenoid
component 360 is illustrated as concave, but could be convex
depending on the application.
[0129] FIG. 24 is a schematic illustration of a glenoid component
380 of an anatomical shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. An
opposing face 382 of the glenoid component 380 is non-planar and
keel 384. The keel 384 optionally includes holes 390 to facilitate
bone in-growth. A distal surface 386 of the bone graft 388 is
preferably formed with a shape complementary to opposing surface
382. The bone graft 388 can be a one-piece bone volume or a puree
of bone substance. In one embodiment, a cut-out is formed in the
bone graft 388 to receive the keel 384. In another embodiment, the
bone graft 388 is an annular ring and the keel is located in the
center opening and secured using a puree of bone substance, bone
cement, or a variety of adhesives.
[0130] FIG. 25 is a schematic illustration of a glenoid component
400 of an anatomical shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. An
exposed surface 402 of the glenoid surface G is non-planar. In the
illustrated embodiment, the exposed surface 402 has a shape
complementary to keel 404 on opposing face 406 of the glenoid
component 400.
[0131] FIG. 26 is a schematic illustration of a glenoid component
420 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. An
exposed surface 422 of the glenoid surface G is non-planar. In one
embodiment, the various shapes 424a, 424b, 424c, 424d (collectively
"424") illustrated in FIG. 26 are formed in the glenoid surface G,
such as for example to remove defects in the surface of the glenoid
surface G and to increase the stability of the glenoid component
420.
[0132] The bone graft 426 can be a one-piece volume, a plurality of
pieces, puree of bone substance, or a combination thereof. In one
embodiment, a plurality of pre-formed bone grafts of known shape
are available to the surgeon during the procedure. The surgeon
removes material from the exposed surface 422 of the glenoid
surface G corresponding to the shape of one of the pre-formed bone
grafts. The surgeon then places the pre-formed bone graft into the
corresponding recess formed in the glenoid surface G.
[0133] FIG. 27 is a schematic illustration of a glenoid component
440 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. The
glenoid component 440 includes a recess 442 that engaged with base
plate 444. The bone graft 458 can be a one-piece bone volume or a
puree of bone substance.
[0134] In the illustrated embodiment, anchor 446 of the base plate
444 and/or the glenoid component 440 are located off-set from the
center axis 448 of the glenoid surface G. Lower portion 450 of the
convex articular surface 452 extends beyond the pillar of the
scapula S to minimize interference with the humeral prosthetic
portion. The radius of curvature of convex articular surface 452 is
preferably selected so the center of rotation around the glenoid
component 440 is preferably in a plane 454 comprising a distal
surface 456 of the bone graft 458 or between the plane 454 and the
glenoid surface G.
[0135] In the illustrated embodiment, the exposed surface 460 of
the glenoid surface G includes one or more defects 462. These
defects 462 are preferably repaired with a one-piece bone graft, a
plurality of pieces, puree of bone substance, or a combination
thereof 464. After the repair, the exposed surface 460 of the
glenoid surface G is preferably generally planar and well suited to
receive the bone graft 458.
[0136] FIG. 28 is a schematic illustration of a glenoid component
480 of an inverted shoulder prosthesis attached to the glenoid
surface G according to an embodiment of the present invention. End
faces 482, 484 of the bone graft 486 are not parallel. In the
illustrated embodiment, an anchor 488 of the glenoid component 480
is at an angle with respect to horizontal axis 490 of the glenoid
surface G. As a result, a surface 492 of the bone graft 486 acts as
an extension of a lower portion of the convex articular surface
494.
[0137] FIG. 29 is a schematic illustration of the glenoid component
480 of FIG. 28 with the anchor 488 at a different angle with
respect to the horizontal axis 490 of the glenoid surface G.
Surface 496 of the bone graft 486 acts as an extension of an upper
portion of the convex articular surface 494.
[0138] FIGS. 30A-30F illustrate an alternate method and apparatus
for forming a bone graft 500 ex vivo in accordance with an
embodiment of the present invention. The humeral epiphysis E is
resected from the humerus H (see e.g., FIG. 7). In the illustrated
embodiment, the resected humeral epiphysis E includes a planar
surface P created during the resection and a curvilinear surface
C.
[0139] The curvilinear surface C of the humeral epiphysis E is
located on base 502, as illustrated in FIG. 30A. A cover 504
illustrated in FIG. 30B secures the humeral epiphysis E to the base
502. As illustrated in FIG. 30C, boring instrument 506 is inserted
through opening 508 in the cover 504. The boring instrument 506 may
be operated by hand or a motorized driver. In an alternate
embodiment, the instrument 506 is an impaction instrument that does
not include teeth 510.
[0140] In one embodiment, the resulting bone graft 500 is an
annular ring with a planar surface 512 and a curvilinear surface
514 as illustrated in FIG. 30D. In an alternate embodiment, cutting
instrument 516 is inserted through slot 518 in cover 504 so that
the bone graft 500 is an annular ring with opposing planar
surfaces, as illustrated in FIG. 30F.
[0141] Various modifications and additions can be made to the
exemplary embodiments discussed without departing from the scope of
the present invention. For example, the distal surfaces of the
glenoid components disclosed herein can be used with an
interpositional implant, such as disclosed in U.S. Pat. Nos.
6,436,146; 5,723,018; 4,846,840; 4,206,517; and U.S. Provisional
Application Ser. No. 61/015,042, entitled INTRA-ARTICULAR JOINT
REPLACEMENT, the complete disclosures of which are hereby
incorporated by reference. While the embodiments described above
refer to particular features, the scope of this invention also
includes embodiments having different combinations of features and
embodiments that do not include all of the described features.
Accordingly, the scope of the present invention is intended to
embrace all such alternatives, modifications, and variations as
fall within the scope of the claims, together with all equivalents
thereof.
* * * * *