FR2871369A1 - Glenoidal component for shoulder prosthesis, has metallic unit defining convex articulation surface which has semi-sphere shape and centered on symmetry axis that is not perpendicular to rear side of component - Google Patents

Abstract

The component has a metallic unit (22) defining a convex articulation surface (S 2) which has a semi-sphere shape and centered on a symmetry axis (X 2 - X` 2). The symmetry axis is not perpendicular to rear side (26) of the component. The symmetry axis is directed towards base (21), when the rear side of the component is vertical. The component is configured such that the symmetry axis is horizontal when a patient stands. An independent claim is also included for an overall shoulder prosthesis including a glenoidal component.

Description

The present invention relates to a glenoid component of a prosthesis

  as well as a set of such components that can be used to form a prosthesis. The invention also relates to a prosthesis

  shoulder comprising such a component as well as a method of laying such a component.

  In the field of shoulder prostheses, it is known, for example from US Pat. No. 3,978,528, to constitute an inverted prosthesis in which a convex articular surface integral with the glenoid and a concave articular surface integral with the humerus cooperate to recreate a joint at the shoulder. In this kind of prosthesis, the glenoid component can be formed, as is clear from FR-A-2,835,425, a base intended to be immobilized on the glenoid and an element intended to be mounted on this base and defining the convex hinge surface.

  It is also known from FR-A-2 836 039 to provide a possibility of mounting a member forming a convex hinge surface on a corresponding base in different positions, which allows adjustment of the articular surface height by report to the glenoid.

  The base or the base of the known glenoid components is provided with a so-called rear face intended to bear against a resected surface of the glenoid which is normally substantially vertical when the patient is standing. However, it happens that the upper part of the scapula is worn or destroyed, to the point of modifying the kinematics of the implant by the displacement of the original center of rotation, which has the effect of limiting the movements of the arm of the patient.

  It is these drawbacks that the invention intends to remedy more particularly by proposing a glenoid component which makes it possible to ensure a good positioning of the convex hinge surface, even when the glenoid is damaged or worn in the upper part, or even in the lower part.

  In this spirit, the invention relates to a glenoid component of a shoulder prosthesis which forms a convex hinge surface centered on an axis of symmetry. This component is characterized in that the axis of symmetry of the convex hinge surface is non-perpendicular to a rear face of the component which is intended to bear against the glenoid.

  Thanks to the invention, the convex hinge surface can be inclined downwards or poured relative to the rear face of the component, which allows to correctly orient this articular surface, including when the bearing surface created in the glenoid by resection is not parallel to the direction of the patient's spine. The invention therefore makes it possible to compensate for or compensate for a lack of parallelism between the resected surface of the glenoid and the axis of the patient's spine.

  According to advantageous but not mandatory aspects, a glenoid component may incorporate one or more of the following features taken in any technically permissible combination: - In the assembled configuration of the component and when the rear face is vertical, the axis of symmetry of the surface of the component convex hinge is directed downward away from the back face.

  - The component comprises a base adapted to be immobilized on the glenoid of a shoulder and an element provided to be mounted on this base and defining the convex articular surface, while the base is provided with a substantially flat front face in which is drilled a housing for receiving a centering finger of the element forming the convex hinge surface, this housing being centered on an axis substantially perpendicular to the front face, this front face not being parallel to the rear face of the base. In this case, the front and rear faces of the base can form between them an angle of between 2 and 18. The base may be provided with an axisymmetric surface centered on an axis perpendicular to its front face, this surface being adapted to cooperate with an inner surface of the aforementioned element for its centering and its immobilization on the base.

  - The component may be provided with an anchor tail which extends in a direction which is not perpendicular to at least part of its rear face.

  - The component comprises a base adapted to be immobilized on the glenoid of a shoulder and a member adapted to be mounted on this base and defining the convex articular surface, while the element which forms the convex hinge surface is provided with a skirt not symmetrical with respect to the axis of the aforementioned surface, which extends this surface and in which is defined, at least in part, a receiving housing of at least a portion of the base. This skirt may be substantially in the form of a torus section. The element which defines the convex hinge surface is advantageously provided with a bore for the passage of an actuating member of a means for securing this element to the base, this passage extending substantially in a direction generally. perpendicular to this surface but not confused with its axis of symmetry.

  The invention also relates to a set of glenoid components for shoulder prosthesis of the type defined above which allows a surgeon to select a component of geometry adapted according to the effective configuration of the glenoid once it resected. This set of components is characterized in that the orientation of the axis of symmetry of the convex hinge surface, with respect to a rear face of each component intended to bear against the glenoid, is variable of a component to the other.

  According to a first variant embodiment, the front and rear faces of the bases of the components may not be parallel to each other, in which case the angle between these front and rear faces is different from one component to the other.

  According to another variant, the elements of these components which form a convex articular surface may each be provided with a skirt, as mentioned above, the dimensions of the skirts being different from one component to another.

  The invention also relates to a total shoulder prosthesis which comprises a glenoid component as described above or selected from a set of components as described above.

  The invention finally relates to a method for fitting a glenoid component of a total shoulder prosthesis, such a component defining a convex articular surface centered on an axis of symmetry, whereas this method comprises the steps of: - milling the glenoid the patient to create a support surface of the component; selecting, from among several glenoid components whose axes of symmetry of the convex articular surfaces are oriented differently with respect to their bearing surface against the resected surface of the glenoid, a component which can be pressed against this surface in a position such that the The aforementioned axis of symmetry is generally perpendicular to the direction of the patient's spine and immobilize the selected glenoid component on the glenoid in the aforementioned position.

  The invention will be better understood and other advantages thereof will become more apparent in the light of the following description of five embodiments of a glenoid component and two embodiments of a set of glenoid components. in accordance with its principle, given solely by way of example and with reference to the accompanying drawings in which: - Figure 1 is a schematic representation of a shoulder prosthesis according to the invention implanted on a patient in a first configuration; - Figure 2 is a view similar to Figure 1 for a prosthesis also according to the invention implanted in a second configuration; FIG. 3 is an exploded side view of the glenoid component used in the prosthesis of FIG. 2; - Figure 4 is a perspective view of a base belonging to the component shown in Figure 3; FIG. 5 is a schematic representation of a set of glenoid components incorporating that represented in FIGS. 3 and 4; FIG. 6 is a view similar to FIG. 3 for a component according to a second embodiment of the invention; Figure 7 is a view similar to Figure 3 for a component according to a third embodiment of the invention; - Figure 8 shows a glenoid component according to a fourth embodiment of the invention, the base is shown in side view and whose element defining the convex articular surface is shown in cross section; FIG. 9 is an exploded perspective view of the component of FIG. 8; FIG. 10 is a view similar to FIG. 8 for a component according to a fifth embodiment of the invention; and FIG. 11 is a view similar to FIG. 9 for the component of FIG.

  The prosthesis P shown in Figure 1 comprises a humeral component 1 comprising a rod 11 to be anchored in the medullary canal of the humerus H and a metaphyseal portion 12 in which is immobilized a polyethylene cup 13 defining a joint surface concave S1 substantially in the shape of a sphere section.

  According to a variant not shown of the invention, the component 1 may be devoid of cup 13, the surface S1 being formed by the metaphyseal part which is metallic.

  The prosthesis P also comprises a glenoid component 2 which defines a convex articular surface S2 substantially in the shape of a half-sphere.

  For the sake of clarity, component 1 is shown in section, while component 2 is shown in an external view in FIG.

  The surface S2 is substantially in the shape of a half-sphere and X2X'2 denotes the axis of symmetry on which this surface is centered.

  Z-Z 'is also noted as a vertical axis passing through the center of the vertebral column of the patient who is standing.

  SG is noted the milled surface of the glenoid G against which bears the component 2 when mounted on the glenoid.

  Normally, the surface SG is substantially parallel to the axis Z-Z ', so that an axis XG-X'G normal to the surface SG and passing through its center is substantially perpendicular to the axis Z-Z' that is to say substantially horizontal when the patient is standing. In the configuration of FIG. 1, which corresponds to a nominal layout configuration, the XG-X'G and X2-X'2 axes coincide and both are horizontal.

  However, as shown in FIG. 2, it happens that the surface SG is not really parallel to the axis Z-Z ', in particular because of a wear of the glenoid G or a partial destruction thereof in the upper part, even in the lower part. In this case, the surface SG forms a non-zero angle with respect to a straight line Z1-Z'1 parallel to the axis ZZ 'and passing through the center MG of the surface SG. When the patient is standing, the axis XG-X'G forms, relative to the horizontal, the same angle a.

  According to the invention, the component 2 is configured so that the axis X2-X '2 of the surface S2 is substantially horizontal when the patient is standing, despite the non-optimal orientation of the surface SG.

  The component 2 is shown in an exploded side view in FIG. 3 and comprises a base or plate 21 intended to be fixed on the glenoid G, as well as a metal element 22, sometimes referred to as a head, which defines the surface S2 and which is provided with a centering finger 23 intended to penetrate into a housing 24 formed in the base 21 and centered on an axis X24-X'24 perpendicular to the front face 25 of the base 21 which is substantially flat and oriented at the opposite of the glenoid when the base is mounted on the glenoid.

  Note 26 the rear face of the base 21 which bears against the surface SG in mounted configuration of the base.

  An anchor tail 27 extends from the surface 26 in a direction parallel to an axis X27-X'27 perpendicular to the surface 26.

  The base 21 is also pierced with four orifices 28 for the passage of four screws 29 represented solely by their centerlines in FIG. 4.

  The front face 25 is disk-shaped centered on the X24-X'24 axis and bordered by a frustoconical surface 30, centered on the X24-X'24 axis and converging opposite the tail 27.

  The surface 30 extends all around the front face 25 but rejoins the rear face 26 on only a part of the periphery of the base 21.

  The face 26 is substantially flat and the faces 25 and 26 are not parallel to each other. We note 0 the non-zero angle formed between the faces 25 and 26.

  The inclined nature of the front face 25 relative to the rear face 26 of the base 21 makes it possible to make up completely or partially the inclined character with respect to the straight line Z1-Z'1 of the surface SG, provided that the part Less thick of the base 21, which is shown on the right of Figure 3, is disposed in the vicinity of the lower part of the surface SG, that is to say, the part located on the side of the patient's ribs.

  When the base or plate 21 has been anchored to the glenoid G as indicated above thanks to the shank 27 and to the introduction of the four screws 29, the element 22 can be put in place by introducing the finger 23 into the housing 24 and carrying an inner surface 31 of the element 22 shown in phantom only in Figure 3 against the surface 30. The geometries of the surfaces 30 and 31 are adapted to obtain a lock in the manner of a Morse taper .

  Thus, the relative orientation of the faces 25 and 26 makes it possible to orient the axis X 2 -X '2 of the surface S 2 downwards in FIG. 2 with respect to the axis XGX' G in its portion which exceeds the glene, that is to say to bring this axis in substantially horizontal configuration, while the SG surface is not parallel to the Z-Z 'axis.

  Given the relative orientation of the faces 25 and 26, the surface 30 borders the face 25 only a fraction of the height of the portion of the base located between the faces 25 and 26. Note 32 the surface portion peripheral of the base 21 which is not formed by the portion 30. This surface is left.

  As is more particularly apparent from FIG. 5, a set of glenoid components according to the invention can incorporate several glenoid components 2a, 2b, 2c and 2d whose bases 21a, 21b, 21c and 21d have front faces 25a, 25b, 25c and 25d which make angles, 6a, Pb, $ c,, 3d different from their respective rear faces 26a, 26b, 26c and 26d. Note that the front and rear faces of the base 21d are substantially parallel, the angle, 6d between them is then zero.

  The element 22 associated with each base 21a, 21b, 21c and 21d may be the same or different from one component to another.

  Thus, when a surgeon places a shoulder prosthesis P, he can, depending on the relative orientation of the SG surface and the Z-Z 'axis, choose a glenoid component whose base comprises front faces and rear oriented in a way to make up most of the defect orientation SG surface.

  Of course, the number of glenoid components of a game such as that shown in Figure 5 is not necessarily four. It can be chosen according to the desired accuracy. In addition, it is not mandatory that, in such a game, a plate has surfaces parallel to each other, such as that shown on the right of Figure 5. Note however that the glenoid component shown on the right of the figure 5 can be used when the prosthesis P is to be implanted in the configuration of FIG.

  The installation of a total shoulder prosthesis is facilitated by the use of such a set of components insofar as the surgeon can select a glenoid component effectively adapted to the patient's morphology and then immobilize this component in a position such that the axis of symmetry of the convex articular surface is substantially perpendicular to the longitudinal axis of the patient's spine.

  In the second embodiment of the invention shown in FIG. 6, elements similar to those of the first embodiment carry identical references increased by 100. The glenoid component 102 of this embodiment comprises an element 122 which carries a substantially hemispherical convex articular surface, this element being identical to that of the first embodiment. The base 121 of the component 102 also comprises an anchoring stem 127. This anchoring tail is centered on an axis X 27 -X '27 perpendicular to the front face 125 of the base 121 which is flat and bordered by a surface frustoconical 130. The base 121 is provided with a housing 124 for receiving a finger 123 belonging to the element 122, the finger being centered on the axis X2-X'2 of symmetry of the surface S2. The central axis X124-X'124 of the housing 124 coincides with the central axis X127-X '127 of the shank 127.

  This embodiment differs from the previous one in that the rear face 126 of the base 121 is not perpendicular to the axis X127-X'127, so that a non-zero angle θ exists between the faces 125 and 126.

  In this embodiment, it can be considered that the rear face 126 is provided with a heel or wedge 134 which serves to compensate for the non-optimal orientation of the surface SG.

  In the third embodiment of the invention shown in FIG. 7, elements similar to those of the first embodiment carry identical references increased by 200. The glenoid component 202 of this embodiment comprises a base 221 as well as an element 222 which forms a substantially hemispherical articular surface S2 centered on an axis X2-X '2 on which is also centered a centering pin 223.

  The front 225 and rear 226 of the base 221 are not parallel to each other and define a non-zero angle. This embodiment incorporates certain elements of the first and second embodiments, namely that the surfaces 225 and 226 are both inclined, in different directions, relative to a longitudinal axis X227-X'227 of an anchor tail. 227 of the base 221 in the glenoid.

  In the fourth embodiment of the invention shown in FIGS. 8 and 9, elements similar to those of the first embodiment carry identical references increased by 300. The glenoid component 302 of this embodiment comprises a base 321 similar to that of the component shown on the right of Figure 5, that is to say whose front 325 and rear 326 are substantially parallel to each other and perpendicular to a central axis X327-X'327 of an anchor tail 327.

  An element 322 intended to be mounted on the base 321 defines a surface S2 substantially in the shape of a half-sphere and centered on an axis X2-X'2 which is not parallel to the axis X327-X '327 in mounted configuration of element 322 on the base 321. To do this, the portion 322a of the element 322 which defines the surface S2 is extended by a skirt 322b in the form of a torus portion centered on an axis Xc perpendicular to the axis X2-X'2 and tangent to the convex articular surface S2 in the vicinity of an intersection zone between this surface S2 and a plane H perpendicular to the axis X2-X'2 and passing through the center C2 of the surface S2 . There is noted the angular amplitude of the skirt 322, that is to say the angle between the plane 7r and the rear face 322c of the element 322 intended to be turned towards the resected surface of the glenoid in mounted configuration component 302.

  A housing 332 is formed inside the element 322, both in the skirt 322b and in the portion 322a. This housing is intended to receive the part of the base 321 defined between the surfaces 325 and 326. The housing 332 is bordered by a frustoconical surface 331 and convergent towards the surface S21 while a surface 330 of the same geometry is provided on the element 321 between the faces 325 and 326.

  Note 333 the circular inlet opening of the housing 332.

  The surface S2 is pierced with a passage 334 allowing the insertion of a tool in the direction of the arrow F3 to the inside of the element 322, which makes it possible to maneuver a screw the element 322 on the base 321. Such a screw may, in particular, control the movement of a finger such as the finger 23 of the first embodiment, which is then threaded, to bring it into engagement with a threaded portion of the base 321, this in accordance with the technical teaching of FR-A-2,835,425.

  X334-X'334 is the longitudinal axis of the passage 334. This axis is perpendicular to the surface S2 and offset from the angle y with respect to the axis X2-X'2.

  In the fifth embodiment of the invention shown in FIG. 10, elements similar to those of the first embodiment bear identical references increased by 400. The glenoid component 402 of this embodiment is produced according to the same principle as that of the fourth embodiment with a base 421 identical to the base 321 and an element 422 which defines a surface S2 centered on an axis X2-X '2 inclined downwards in Figure 10. This embodiment differs from the previous in that the angular amplitude y of the skirt 422b, which extends the portion 422a of the element 422 defining the surface S2, is greater than in the embodiment of FIGS. 8 and 9, which makes it possible to increase the spill effect of the surface S2 with respect to the rear face 426 of the base 421.

  The components shown in FIGS. 8 to 11 can be considered as belonging to the same set of glenoid components allowing the surgeon to select the most adapted component as a function of the value of the angle γ and the orientation of the resected surface SG of the glenoid with respect to the longitudinal axis Z-25 Z 'of the patient's spine.

  Of course, the number of components of such a game is not limited to two.

  The characteristics of the different embodiments shown can be combined with each other in that a base or plate with non-parallel front and rear faces could be used with an element provided with a skirt extending the portion of this element defining a joint surface. convex axisymmetric.

  The invention also allows for proper implantation of a glenoid component when the lower portion of the scapula is damaged. It is then sufficient to return the component with respect to the configuration shown in FIG.

  The invention has been shown with bi-partite glenoid components. It also applies, however, to monoblock glenoid components.

Claims (13)

  A glenoid component of a shoulder prosthesis forming a convex hinge surface centered on an axis of symmetry, characterized in that said axis of symmetry (X2-X '2) is non-perpendicular (0, r) to a rear face (26,126; 226; 326; 426) of said component (2; 102; 202,302; 402) intended to bear against the glenoid (G).   2. Component according to claim 1, characterized in that in mounted configuration of said component (2; 102; 202; 302; 402) and when said rear face (26; 126,226; 326; 426) is vertical, said axis ( X2X'2) is directed downward away from said rear face.   3. Component according to one of the preceding claims, characterized in that it comprises a base (21; 121; 221), adapted to be immobilized on the glenoid of a shoulder, and a member (22; 122; 222). , adapted to be mounted on said base and defining said surface (S2), and in that said base is provided with a substantially planar front face (25; 125; 225) in which a housing (24; receiving a finger (23 123; 223) for centering said element (22; 122; 222), said housing being centered on an axis (X24-X'24; X124-X'124) substantially perpendicular to said front face, said front face not being parallel (0) to the rear face (26; 126; 226) of said base.   4. Component according to claim 3, characterized in that said front (25; 125; 225) and rear (26; 126; 226) faces together form an angle (0) between 2 and 18.   5. Component according to one of claims 3 or 4, characterized in that said base (21; 121; 221) is provided with an axisymmetrical surface (30; 130) centered on an axis (X24-X'24; X124 -X '124) perpendicular to said front face (25; 125; 225), said surface being adapted to cooperate with an inner surface (31) of said member (22; 122; 222) for centering and immobilizing said element on said base.   6. Component according to one of the preceding claims, characterized in that it is provided with an anchor (127; 227) which extends in a direction which is not perpendicular to at least a part of said rear face (126; 226).   7. Component according to one of the preceding claims, characterized in that it comprises a base (321; 421), adapted to be immobilized on the glenoid of a shoulder, and a member (322; 422) intended to be mounted. on said base defining said surface (S2) and in that said element is provided with a non-symmetrical skirt (322b; 422b) (y) with respect to said axis, which extends said convex articular surface (S2) and in which is defined at least in part, a housing (332) for receiving at least a portion of said base (321; 421).   8. Component according to claim 7, characterized in that said skirt (322b; 422b) is substantially in the form of a torus section.   9. Component according to one of claims 7 or 8, characterized in that said element (322; 422) is provided with a piercing (334) passage (F3) of a body of maneuver means of securing said element to said base (321; 421), said piercing extending substantially in a direction (X334-X'334) generally perpendicular to said surface (S2) and not coincidental (y) with said axis (X2-X ' 2) 10. Set of glenoid components for shoulder prosthesis in which each component forms a convex hinge surface centered on an axis of symmetry, characterized in that the orientation (0, y) of said axis of symmetry (X2-X ' 2), with respect to a rear face (26; 126; 226; 326; 426) of each component intended to bear against the glenoid (G), is variable from one component to another (2a-2d; 302, 402).   11. Set of components according to claim 10, characterized in that the components are according to claim 3 and in that the angle (a) between the front (25; 125; 225) and rear (26; 126; 226) faces. ) bases (21; 121; 221) is different from one component to another (2a-2d).   12. Set of components according to claim 10, characterized in that the components are according to claim 7 and in that the dimensions (y) of the skirts (322b, 422b) are different from one component to another (302, 402).   13. Total shoulder prosthesis, characterized in that it comprises a glenoid component (2; 102; 202; 302; 402) according to one of claims 1 to 9 or selected from a set of components (2a-2d; 302, 402) according to one of claims 10 to 12.