U.S. patent application number 15/453051 was filed with the patent office on 2017-06-22 for humeral component of a shoulder joint prosthesis.
The applicant listed for this patent is DIDIER CAPON, DAVID COLLINS, LIEVEN DE WILDE, ANDERS EKELUND, LAURENT LAFOSSE, CECILE NEROT, DIDIER PONCET, LUDWIG SEEBAUER, MICHAEL WIRTH. Invention is credited to DIDIER CAPON, DAVID COLLINS, LIEVEN DE WILDE, ANDERS EKELUND, LAURENT LAFOSSE, CECILE NEROT, DIDIER PONCET, LUDWIG SEEBAUER, MICHAEL WIRTH.
Application Number | 20170172751 15/453051 |
Document ID | / |
Family ID | 35395100 |
Filed Date | 2017-06-22 |
United States Patent
Application |
20170172751 |
Kind Code |
A1 |
PONCET; DIDIER ; et
al. |
June 22, 2017 |
HUMERAL COMPONENT OF A SHOULDER JOINT PROSTHESIS
Abstract
A humeral component of a reverse shoulder prosthesis includes a
stem part configured for location within the intramedullary cavity
of the humerus, the stem part having a stem axis, an epiphyseal
part connected to the elongate stem part and having a concave
bearing surface defining an epiphyseal axis, and wherein the
epiphyseal axis is offset posteriorly relative to the stem
axis.
Inventors: |
PONCET; DIDIER; (BRON,
FR) ; NEROT; CECILE; (REIMS, FR) ; CAPON;
DIDIER; (SAUTRON, FR) ; SEEBAUER; LUDWIG;
(FORSTINNING, DE) ; EKELUND; ANDERS; (BROMMA,
SE) ; DE WILDE; LIEVEN; (GENT, BE) ; WIRTH;
MICHAEL; (SAN ANTONIO, TX) ; COLLINS; DAVID;
(LITTLE ROCK, AR) ; LAFOSSE; LAURENT; (ANNECY LE
VIEUX, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PONCET; DIDIER
NEROT; CECILE
CAPON; DIDIER
SEEBAUER; LUDWIG
EKELUND; ANDERS
DE WILDE; LIEVEN
WIRTH; MICHAEL
COLLINS; DAVID
LAFOSSE; LAURENT |
BRON
REIMS
SAUTRON
FORSTINNING
BROMMA
GENT
SAN ANTONIO
LITTLE ROCK
ANNECY LE VIEUX |
TX
AR |
FR
FR
FR
DE
SE
BE
US
US
FR |
|
|
Family ID: |
35395100 |
Appl. No.: |
15/453051 |
Filed: |
March 8, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12088907 |
Feb 9, 2009 |
9610165 |
|
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PCT/IB2006/002952 |
Oct 2, 2006 |
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15453051 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/30507
20130101; A61F 2002/30487 20130101; A61F 2002/4022 20130101; A61F
2250/0006 20130101; A61F 2002/4051 20130101; A61F 2002/30538
20130101; A61F 2002/30253 20130101; A61F 2002/4037 20130101; A61F
2220/0025 20130101; A61F 2002/3054 20130101; A61F 2002/305
20130101; A61F 2002/30617 20130101; A61F 2002/30884 20130101; A61F
2002/30604 20130101; A61F 2250/0097 20130101; A61F 2220/0033
20130101; A61F 2310/00011 20130101; A61F 2002/4044 20130101; A61F
2002/30331 20130101; A61F 2230/0076 20130101; A61F 2/4059 20130101;
A61F 2002/30616 20130101; A61F 2/4014 20130101; A61F 2002/3082
20130101 |
International
Class: |
A61F 2/40 20060101
A61F002/40 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2005 |
GB |
0519994.8 |
Claims
1-13. (canceled)
14. A humeral component of a reverse shoulder prosthesis,
comprising: a. an elongate stem part for location within the
intramedullary cavity of the humerus, the stem part having a
proximal face; and b. an epiphyseal part having (i) a concave
bearing surface for articulation with the convex bearing surface of
a glenoid component, (ii) an opposite distal face which is directed
towards the proximal face of the stem part when the stem part and
the epiphyseal parts are assembled, and (iii) a surface extending
between the distal face and the concave bearing surface; wherein
the elongate stem part defines a stem axis and the concave bearing
surface of the epiphyseal part defines an epiphyseal axis, and in
which one of the distal face of the epiphyseal part and the
proximal face of the stem part carries a spigot connection feature
and the other of the distal face of the epiphyseal part and the
proximal face of the stem part carries a socket connection feature
in which the spigot connection feature can be received so that the
epiphyseal part and the stem part can be assembled with one
another, the connection feature on the epiphyseal part being offset
relative to the epiphyseal axis so that the epiphyseal axis in the
assembled humeral component is offset posteriorly relative to the
stem axis; wherein the surface of the epiphyseal part which extends
between the distal face and the concave bearing surface is adapted
to contact bone tissue and to be positioned within the cortical
tissue of the humerus.
15. The humeral component as claimed in claim 14, wherein the
distance between the stem axis and the epiphyseal axis is at least
about 1.5 mm.
16. The humeral component as claimed in claim 14, wherein the
distance between the stem axis and the epiphyseal axis is not more
than about 7 mm.
17. The humeral component as claimed in claim 14, wherein the
epiphyseal part comprises a shell part which defines a recess, and
a bearing part which can be received in the shell part and which
provides the bearing surface for articulation with a glenoid
component.
18. The humeral component as claimed in claim 17, wherein the rim
of the shell part is approximately circular.
19. The humeral component as claimed in claim 17, wherein the rim
of the shell part is approximately planar.
20. The humeral component as claimed in claim 19, wherein the plane
defined by the rim of the shell part is approximately perpendicular
to the epiphyseal axis.
21. The humeral component as claimed in claim 14, wherein the angle
between the stem axis and the epiphyseal axis, when viewed along
the anterior-posterior axis, is at least about 20.degree..
22. The humeral component as claimed in claim 14, wherein the angle
between the stem axis and the epiphyseal axis, when viewed along
the anterior-posterior axis, is not more than about 35.degree..
Description
[0001] A shoulder joint prosthesis comprises a humeral component
having a stem part which can be fitted into the intramedullary
cavity of the humerus, and a glenoid part. In the natural joint,
the humeral component provides a convex head, which articulates
against a concave bearing surface on the glenoid. This structure is
reproduced in so-called "anatomic" shoulder joint prostheses, in
which the humeral component includes a stem part, and a head part
with a convex bearing surface and the glenoid component provides a
concave bearing surface. The stem part is implanted within the
humerus. The head part is fitted to the stem part (generally using
a spigot and socket arrangement) so that it sits above the
resection plane of the humerus. Anatomic prostheses are suitable
for implantation in patients in which joint tissue has degraded
(for example due to arthritis).
[0002] The use of modular components to form the humeral component
of a shoulder joint prosthesis is known, particular in relation to
anatomic shoulder joint prostheses. For example, such modular
components are disclosed in U.S. Pat Nos.-5,314,479 and 5,358,526.
The connection between stem and head parts of anatomic shoulder
joint prostheses can provide for a variable offset between the two
parts, to suit the anatomy of a particular patient.
[0003] The structure of the anatomic joint is reverse in so-called
"reverse" shoulder joint prostheses, in which the glenoid component
includes a convex head, and the humeral component has a concave
recess in the epiphysis, in which the head on the glenoid component
can be received and articulate. In contrast with anatomic shoulder
joint prostheses, the humeral component of the reverse joint
prosthesis, including the epiphyseal part which provides the
bearing surface, is implanted almost entirely within the
humerus.
[0004] The biomechanical properties of the patient's joint are
altered when a reverse shoulder joint prosthesis is implanted
because the prosthesis results in the centre of rotation of the
joint being shifted medially. A reverse shoulder joint prosthesis
is suitable for implantation in a patient with damaged cuff muscle
tissue. The shift of the centre of rotation then allows
manipulation of the arm using the deltoid muscle because of the
increased mechanical advantage that results.
[0005] There are significant differences between anatomic and
reverse shoulder joint prostheses in terms of design features and
techniques for implantation. In an anatomic shoulder joint
prosthesis, the angle between the axis of the humeral head (which
is the axis of symmetry of the head, usually passing through the
pole of the sphere of which the bearing surface of the head forms a
part) and the stem axis is about 135.degree.. In a reverse shoulder
joint prosthesis, the corresponding angle is generally larger, for
example about 155.degree.. Further-more, in a reverse shoulder
joint prosthesis, it is known to introduce an anteversion angular
offset between the epiphysis and the stem part of up to about
40.degree., for example of about 20.degree.. This angular offset
can improve the range of movement of the joint after implantation,
in particular increase the range of internal rotation. This can be
achieved in a humeral component which comprises modular stem and
epiphyseal parts by rotating the epiphyseal part relative to the
stem part about the stem axis.
[0006] According to the present invention, it has been found that
the range of joint articulation can be increased further in a
reverse shoulder joint prosthesis by offsetting the epiphyseal axis
of the humeral component posteriorly relative to the stem axis.
[0007] Accordingly, in one aspect, the invention provides a humeral
component of a reverse shoulder prosthesis, which comprises an
elongate stem part for location within the intramedullary cavity of
the humerus, and an epiphyseal part having a concave bearing
surface for articulation with the convex bearing surface of a
glenoid component, in which the elongate stem part defines a stem
axis and the concave bearing surface of the epiphyseal part defines
an epiphyseal axis, and in which the epiphyseal axis is offset
posteriorly relative to the stem axis.
[0008] The humeral component of the invention has the advantage of
allowing increased range of joint articulation (in particular,
internal rotation). This is achieved by creating a lever arm for
the subscapularis (which contributes to defining the range of
internal rotation).
[0009] A further significant advantage of the humeral component of
the invention is that the risk of impingement between the rim of
the epiphyseal part and cortical tissue of the humerus is reduced,
in particular when there is an anteversion angular offset between
the stem and epiphyseal parts. Such impingement can be a
significant disadvantage because it can require removal of cortical
bone tissue to enable the humeral component to be implanted. This
can give rise to undesirable weakening of the patient's tissue.
This is a problem that is particular to reverse shoulder joint
prostheses because of the location of the epiphyseal part of the
humeral component within the humerus.
[0010] Reducing or avoiding impingement between the epiphyseal part
of the humeral component and cortical tissue can allow a larger
epiphyseal part to be implanted which can provide advantages in
terms of load transfer. It can provide a better fit of the humeral
component in the patient's humerus and can allow the component to
be fixed more securely.
[0011] Preferably, the distance between the stem axis and the
epiphyseal axis is at least about 1.0 mm, more preferably at least
about 1.5 mm, for example at least about 2.0 mm. Preferably, the
distance between the stem axis and the epiphyseal axis is not more
than about 7 mm, more preferably not more than about 5 mm, for
example not more than about 3.0 mm.
[0012] Generally, the stem part and the epiphyseal part will be
provided as separate parts, each having a connection feature which
allows the parts to be assembled for use. For example, the
connection feature on one of the stem part and the epiphyseal part
can be a socket and the connection feature on the other of the stem
part will then be a spigot which can be received in the socket.
Preferably, the spigot and socket are circular in cross-section and
are have matching tapers so that they can lock together when
pressed together. As is known, a suitable taper angle can be
between 6 and 8.degree..
[0013] It can be preferred for the posterior offset of the
epiphyseal axis relative to the stem axis can arise as a result of
the connection feature (for example a socket which is tapered
inwardly towards its closed end) on the epiphyseal part being
offset relative to the epiphyseal axis.
[0014] Preferably, the epiphyseal part of the humeral component
comprises a shell part which defines a recess, and a bearing part
which can be received in the shell part and which provides the
bearing surface for articulation with a glenoid component. The
shell part and the bearing part can be made from different
materials. In particular, the bearing part can be made from a
material which provides for low friction articulation with the
convex bearing surface of the glenoid component. Suitable polymeric
materials include ultrahigh molecular weight polyethylene. Ceramic
and metallic materials can also provide the bearing surface of the
humeral component.
[0015] The stem part and at least part of the epiphyseal part of
the humeral component will generally be made from metallic
materials. Suitable metallic materials for use in orthopaedic joint
prostheses are known, and include cobalt-chromium-molybdenum
alloys, certain stainless steels, titanium and certain of its
alloys.
[0016] Preferably, the rim of the shell part is approximately
circular. Preferably, the rim of the shell part is approximately
planar. When implanted, the plane defined by the rim of the shell
part will be arranged approximately parallel to the humeral
resection plane, with the distance between the two planes being
preferably at least about 1.0 mm, and preferably not more than
about 4.0 mm, more preferably not more than about 2.5 mm.
[0017] Preferably, when the rim of the shell part is planar, the
plane defined by the rim of the shell part is approximately
perpendicular to the epiphyseal axis. However, in embodiments in
which the rim is non-planar (for example because of a localised lip
which is provided to reduce the risk of dislocation), the axis is
considered to pass through the pole of the sphere of which the
bearing surface forms a part, arranged symmetrically around the
pole (apart from the localised lip or similar feature).
[0018] Preferably, the angle between the stem axis and the
epiphyseal axis, when viewed along the anterior-posterior axis, is
at least about 20.degree.. Preferably, the said angle is not more
than about 35.degree., for example about 25.degree..
[0019] The humeral component of the invention can be used with a
glenoid component of a reverse shoulder joint prosthesis having
features which are known from existing joint prostheses, for
example from that sold by DePuy Products Inc under the trade mark
DELTA. Such glenoid components include a metaglene component which
is fastened to the glenoid by means of fixation screws. A
glenosphere component is then mounted on the metaglene component,
and fastened to it by means of an inter-engaging spigot and socket
arrangement.
[0020] In another aspect, the invention provides a shoulder joint
prosthesis which comprises a humeral component as discussed above,
and a glenoid component which includes a convex head part which can
be received in the epiphyseal part of the humeral component and
articulate with its concave bearing surface.
[0021] Embodiments of the invention will now be described by way of
example with reference to the accompanying drawings, in which:
[0022] FIG. 1 is a side elevation view of a humeral component of a
shoulder joint prosthesis according to the invention.
[0023] FIG. 2 is an exploded isometric view of the stem and
epiphyseal parts of a humeral component according to the
invention.
[0024] FIG. 3 is another isometric view of the stem and epiphyseal
parts of a humeral component shown in FIG. 2.
[0025] FIG. 4 is a side elevation of a humeral component according
to the invention.
[0026] FIG. 5 is a sectional elevation of the humeral component
shown in FIG. 4.
[0027] FIG. 6 is a side elevation view, partially cut away, of a
humeral component according to the invention implanted in a
patient's humerus.
[0028] FIG. 7 is a view generally along the medial lateral axis of
a shoulder joint, showing the scapula and the humerus, after
implantation of a shoulder joint prosthesis according to the
invention.
[0029] Referring to the drawings, FIGS. 1 to 6 show a humeral
component 2 of a reverse shoulder prosthesis. It comprises an
elongate stem part 4 for location within the intramedullary cavity
of the humerus 6. An epiphyseal part 8 defines a recess for a
bearing part 10. The bearing part has a concave bearing surface 12
for articulation with the convex bearing surface of a glenoid
component (not shown).
[0030] The stem part 4, the epiphyseal part 8 and the bearing part
10 are provided as separate modular parts which are assembled to
form the humeral component prior to implantation. Features which
are incorporated into modular orthopaedic joint prostheses,
especially shoulder joint prostheses, which are suitable for use in
the prosthesis of the present invention are known, for example from
the DELTA and GLOBAL prostheses which are manufactured and sold by
DePuy Products Inc, and from the AEQUALIS prosthesis which is
manufactured and sold by Tornier S A. Details of one embodiment of
humeral component are shown in FIGS. 2 to 5.
[0031] In the embodiment of the humeral component shown in FIGS. 2
to 5, the stem part 4 has a planar proximal face 102, with an axial
bore 104 formed in it, extending normal to the proximal face and
generally along the axis of the part. An upstanding lug 106 is
provided on the proximal face. The stem part has two shoulders 108
at its proximal end which are to provide rotational stability of
the stem part in the humerus after implantation.
[0032] The axial bore 104 is formed in two parts, with a proximal
large diameter plain bore portion 110 and a distal smaller diameter
threaded bore portion 112 which is configured for threaded
engagement with a fixation screw 113 for the epiphyseal part 8.
[0033] The epiphyseal part 8 has a planar distal face 114 with a
short spigot 116 extending from it, normal to the plane of the
distal face 114. The spigot has a bore 117 extending through it
which is configured so that the shank of the fixation screw 113 can
extend through it. The distal face 114 of the epiphyseal part 8 has
seven blind recesses 116 formed in it, in which the lug 106 on the
proximal face of the humeral part can be received.
[0034] The lug and the series of blind recesses allow the angular
orientation of the epiphyseal part relative to the stem part to be
adjusted. This is accomplished by locating the spigot on the
epiphyseal part loosely in the bore on the stem part. The
epiphyseal part can be turned relative to the stem part around the
axis of the stem part. The lug is located in an appropriately
positioned one of the recesses 116 to lock the epiphyseal part
against rotation. The epiphyseal part is then locked to the stem
part by means of the fixation screw 113 engaging the threads in the
small diameter portion 112 of the bore in the stem part.
[0035] FIGS. 4 and 5 show in addition the bearing part 10 of the
humeral component. This and the epiphyseal part have
circumferential grooves 118, 120 formed in them which are aligned
with one another when the parts are properly assembled. A resilient
spring in the form of a zigzag wire formed into an approximately
circular loop can be can be used to fasten the polymeric bearing
part into the stem part of the glenoid component. The spring can be
located in one of the grooves prior to assembly, which is deformed
during assembly, and allowed to relax into the other of the grooves
when the parts are assembled.
[0036] The use of such a spring to fasten a polymeric bearing part
into the stem part of an orthopaedic joint prosthesis is well
known.
[0037] The stem part 4 is formed from an alloy which is suitable
for an orthopaedic joint prosthesis component such as a titanium
alloy or a stainless steel. Suitable materials are known. The
configuration of the stem part is as in known shoulder joint
prostheses. Features of the stem part can include (a) a taper
towards the distal tip, (b) axial flutes in the side walls in the
portion towards the distal tip, (c) a coating over at least part of
the bone engaging surface (particularly in the proximal region) of
a material which promotes fixation of the implant in the
intramedullary cavity, and so on. The configuration of the stem
component should be optimised to ensure that it can be fixed
securely in a patient's humeral cavity, as is known.
[0038] The epiphyseal part 8 of the component will generally be
formed from the same material as the stem part, or at least a
similar material (for example the stem part and the epiphyseal part
might both be formed from metals, especially the same metal).
[0039] The bearing part of the component will frequently be formed
from a polymeric material such as an ultrahigh molecular weight
polyethylene (UHMWPE). Such materials are known for use in
orthopaedic joint prostheses for articulation with bearing surfaces
of other components provided by hard materials including metallic
and ceramic materials. The bearing surface of the humeral component
can be provided by materials other than polymeric materials, for
example by metallic materials or ceramic materials. A bearing part
need not be included in the humeral component, for example when the
epiphyseal part provides the bearing surface. This can be
particularly appropriate when the bearing surface of the humeral
component is provided by a hard material such as a metallic
material or a ceramic material.
[0040] The stem part 4 of the component defines a stem axis 13,
which is intended to be aligned with the patient's humeral axis
when the component is implanted.
[0041] The bearing surface of the humeral component should be
shaped according to the shape of the convex bearing surface of the
glenoid component with which it articulates. The bearing surface of
the humeral component will generally be approximately rotationally
symmetrical, for example in the form of a part of a sphere or part
of an ovoid. (However, when viewed along the axis of symmetry, the
bearing surface need not be circular.) The axis of symmetry of the
bearing surface defines the epiphyseal axis of the humeral
component.
[0042] In the humeral component of the present invention, the stem
axis and the epiphyseal axis are not coincident. Preferably, they
are approximately parallel. However, as shown in FIG. 1, the
epiphyseal axis is offset posteriorly relative to the stem axis by
about 2.5 mm.
[0043] FIG. 6 shows the humeral component described above with
reference to FIG. 1 after implantation in a patient's humerus 6. As
shown in FIG. 6, the humerus is prepared for implantation of the
joint prosthesis by resection, as generally known. The bone is
resected along a resection plane 14 which is inclined to the axis
of the humerus.
[0044] It is an advantage of the present invention that the
epiphyseal part 8 of the humeral component, when implanted in the
humerus, can be arranged to lie wholly within the cortical tissue
of the humerus on the resection plane 14. This is possible without
having to compromise the size of the humeral component (which is an
advantage in order to maintain optimum load transfer area on the
articulating surfaces of the prosthesis). The ability to implant
the humeral component without disrupting the cortical tissue of the
humerus has the advantage of minimising weaknesses introduced to
the bone tissue as a result of implantation of the humeral
component.
[0045] FIG. 7 shows a shoulder joint, with a shoulder joint
prosthesis according to the invention implanted therein. A glenoid
component 20 is implanted in the scapula 22, the glenoid component
having a convex articulating surface 24. The glenoid component can
have the features of the corresponding component of the DELTA
shoulder joint prosthesis which is manufactured and sold by DePuy
Products Inc. A humeral component 26, having the features of the
humeral component described above with reference to FIG. 1, is
implanted in the humerus 28.
[0046] Control over international rotation of the shoulder joint is
provided in part by the subscapularis tendon (shown schematically
by a dotted line 30). The tendon is attached to the greater
tuberosity 32 on the humerus, located anteriorly relative to the
humeral axis.
[0047] The mechanical advantage associated with the action of the
subscapularis muscle on the shoulder joint depends on the distance
between the point of attachment of the subscapularis tendon to the
humerus and the centre of rotation of the joint. It is an advantage
of the humeral component of the present invention that the
mechanical advantage is increased as a result of the posterior
offset of the centre of rotation of the joint relative to the axis
of the humerus.
* * * * *