REPLACEMENT MEMBER FOR A JOINT REPLACEMENT

Abstract

The disclosure relates to a replacement member for a shoulder joint replacement comprising an attachment face on one side of the member, a concave joint surface on a side of the replacement member opposite to the side of the attachment face, and a circumferential face connecting the attachment face and the joint surface. A portion of the concave joint surface is connected to at least a portion of the circumferential face via a chamfered or rounded edge.

Claims

1. A replacement member for a shoulder joint replacement comprising an attachment face on one side of the member, a concave joint surface on a side of the replacement member opposite to the side of the attachment face, and a circumferential face connecting the attachment face and the joint surface, wherein a portion of the concave joint surface is connected to the circumferential face via a chamfered or rounded edge.

2. The member of claim 1, wherein the chamfered or rounded edge is configured to be located at an adductive portion of the joint replacement when the implant joint replacement is implanted in a body.

3. The member of claim 1, wherein the concave joint surface face has a curved profile, the curved profile being spherical, ellipsoidal, or ovoid shaped.

4. The member of claim 1, wherein the attachment face is configured to fixedly attach the member to bone tissue or to another replacement member.

5. The member of claim 1, wherein the member is a glenoid replacement or a humeral replacement.

6. The member of claim 1, wherein a section forming the joint surface comprises a composition of Vitamin E and UHMWPE.

7. The member of claim 1, wherein the concave joint surface is configured to engage with a mating joint replacement member.

8. A shoulder joint replacement, comprising: a member, and a mating joint replacement member, wherein the member and the mating joint replacement member engage via a portion of the convex joint surface of the member.

9. A shoulder joint replacement comprising a first replacement member, and a second replacement member, wherein: the first replacement member comprises an attachment face on one side of the member, a concave joint surface on a side of the replacement member opposite to the side of the attachment face, and a circumferential face connecting the circumferential attachment face and the joint surface; the second replacement member comprises a convex joint surface, the convex joint surface forming a ball joint with the concave joint surface of the first replacement member, and an outer surface distal and adjacent to the convex joint surface; and the concave joint surface is partly connected to the circumferential face via a chamfered or rounded edge, the chamfered or rounded edge being arranged such that a clearance is provided between the first replacement member and the second replacement member when the two replacement members are arranged relatively to each other to form a predetermined adducted arrangement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The following figures illustrate preferred embodiments of the present invention. These embodiments are not to be construed as limiting but merely for enhancing the understanding of the invention in context with the following description. In these figures, same reference signs refer to features throughout the drawings that have the same or an equivalent function and/or structure. A repetitive description of these components is generally omitted for reasons of conciseness.

[0047] FIG. 1 is a perspective view of a joint replacement member according to an embodiment.

[0048] FIG. 2A is a perspective view of a joint replacement member according to an embodiment.

[0049] FIG. 2B is a perspective view of an embodiment of an intermediate member for the joint replacement of FIG. 2A.

[0050] FIG. 2C shows the joint replacement member of FIG. 2A and the intermediate member of FIG. 2B in an assembled state.

[0051] FIG. 2D shows a side-view of the replacement member illustrated in FIG. 2A.

[0052] FIG. 2E shows an assembly of a replacement member and an intermediate member according to another embodiment.

[0053] FIGS. 3A, 3B and 3C show a replacement member according to yet another embodiment which is to be mounted directly to surrounding tissue.

DETAILED DESCRIPTION

[0054] FIG. 1 is a perspective view of an exemplary embodiment of a joint replacement member 1. The joint replacement member 1 comprises an attachment face 3 on one side (hidden in the view in FIG. 1). The attachment face 3 can either be a face that is configured to be directly anchored to the surrounding tissue or can be a face that is to be attached to an intermediate member, which is then anchored to the surrounding tissue.

[0055] The joint replacement member 1 shown in FIG. 1 further comprises a concave joint surface 5 on a side of the replacement member 1 opposite to the side of the attachment face 3, said concave joint surface 5 being configured to engage with a mating convex joint replacement member.

[0056] The replacement member 1 further comprises a circumferential face 7 which circumferentially connects the attachment face 3 and the joint surface 5. A portion of the concave joint surface 5 is connected to a portion of the circumferential face 7 via a chamfered or rounded edge 9. In the exemplary embodiment of the figures, the edge 9 is a chamfered edge (see FIG. 2D). As described above, this edge prevents impingement from occurring and an enhanced support.

[0057] A plurality of edges is formed in the embodiment of the replacement member 1: a first edge 2, which surrounds the joint surface 5 along its entire circumference, and a second edge 4. The first edge 2 can be divided into a first portion 2a, which connects the joint surface 5 and the circumferential face 7, and a second portion 2b, which connects the joint surface 5 with the surface of the chamfered or rounded edge 9. The second edge 4 connects the surface of the chamfered or rounded edge 9 with the circumferential face 7.

[0058] Above noted maximum width is defined between the second edge portion 2b and the second edge 4. In the exemplary embodiment of the figures, the maximum width is substantially arranged in the middle between the ends of the chamfered or rounded edge 9. Nonetheless, it may also be situated at a different position but is preferably situated at a position, where impingement may most likely occur.

[0059] The chamfered or rounded edge 9 extends along the second edge portion 2b. In case of a rounded edge 9, the edge portion 2b is preferably parallel or corresponds to the axis defining the center of the rounded edge 9. In case of a chamfered edge 9, the surface of the chamfered edge is preferably curved, wherein the curved surface particularly corresponds to or is formed as a surface section of a truncated cone. In particular, the curved surface of the chamfered edge 9 in cross-sections perpendicular to the curved edge portion 2b is basically uniformly inclined, i. e. it is inclined at a constant angle.

[0060] As a result, impingement is not only prevented in adduction of the shoulder alone but also in adduction during anteversion or retroversion of the shoulder. Further, such a chamfered or rounded edge 9 can easily be manufactured, such as by rotating the replacement member 1 about an axis perpendicular to the joint surface while cutting along the second edge portion 2b.

[0061] It should be noted that the first portion 2a of edge 2 may be slightly chamfered or rounded such as for reasons of production. However, such a first edge portion 2a generally has a constant width that is generally below 3 mm.

[0062] FIG. 2A shows a perspective view of a joint replacement member 1 according to an embodiment which is configured to be used with an intermediate member 500 for a joint replacement according to an embodiment shown in FIG. 2B.

[0063] The intermediate member 500 shown in FIG. 2B comprises a tissue attachment face 513 which is configured to be attached to native tissue such as bone tissue and/or surrounding soft tissue. The tissue attachment face 513 of the embodiment shown in FIGS. 2A, 2B, 2C, 2D comprises a first protrusion 515 and a plurality of second protrusions 517 which are configured to enhance the fixation of the intermediate member 500 in the surrounding tissue. The combination of a first protrusion 515 and at least one second protrusion 517 particularly prevent the intermediate member from rotating about the first protrusion 515.

[0064] The intermediate member 500 further comprises a device attachment face 521 which is configured to mate with a corresponding part of the replacement member 1. The device attachment face 521 of the embodiment has a first through hole 525 which extends through the first protrusion 515 to the other side of the intermediate member 500, i. e. it penetrates the first protrusion 515 along the longitudinal direction of the first protrusion 515.

[0065] Further, second through holes 527 are extending from the device attachment face 521 into the second protrusions 517, such that the through holes 527 penetrate the device attachment face 521 and the second protrusions 517.

[0066] Fasteners, in particular screws, can be inserted through the first 525 and second 527 through holes, and, respectively, through the first 515 and second protrusions 517 in order to anchor the intermediate member 500 to bone tissue adjacent to the intermediate member 500.

[0067] The replacement member 1 has an attachment structure 11 that is configured to mate with a corresponding structure of the first hole 525. While it is noted that only the attachment structure 11 is illustrated in FIGS. 2A and 2B, similar attachment structures may be provided for the interaction between the second through holes 527 of the intermediate member 500 with corresponding protrusions 13 on the replacement member 1.

[0068] In the embodiment shown in FIGS. 2A and 2B, the attachment structure 11 is a snap-fit connection which is configured to snap into a corresponding connection part of the first through hole 525 (not shown). However, it is to be noted that other connections such as taper locks or other alternatives known to the person skilled in the art may be provided in order to secure the replacement member 1 to the intermediate member 500.

[0069] When implanted into a patient, the replacement member 1 and the intermediate member 500 are arranged such that the chamfered or rounded part of the edge is oriented caudally, that is, downwardly.

[0070] FIG. 2E shows an exploded view of an assembly of a replacement member 1 and an intermediate member 500 for implantation into a patient.

[0071] At first, the intermediate member 500 is attached to bone tissue, for example via a fixation member 510, 510′, such as a screw, that is inserted into the first through hole (not visible) within the first protrusion 515. Then, the replacement member 1 is attached to the intermediate member 500, for example by means of a snap-fit connection between the attachment structure 11 and the first through hole (not visible).

[0072] FIGS. 3A, 3B and 3C show another embodiment of a replacement member 100 which is configured to be mounted directly into surrounding tissue without the interposition of an intermediate member.

[0073] Similar to the above, the replacement member 100 comprises a concave joint surface 5, a circumferential face 7, an attachment face 3 and a chamfered edge 9. As described above, the chamfered edge may also be a rounded edge. Like the edge of the previous embodiment, the chamfered or rounded edge 9 is arranged between first and second edges 2, 4 of the joint surface 5 and the circumferential face 7, respectively.

[0074] While the configuration of the embodiment shown in FIGS. 3A, 3B, and 3C is particularly similar to the configuration of the embodiment described with reference to FIG. 2A-E in respect to the side of the replacement member 1 comprising the joint surface 5, the replacement member 100 shown in FIGS. 3A-C differs in the configuration of the attachment face 3.

[0075] The attachment face 3 of the embodiment shown in FIG. 3A-C is configured to be directly attached to surrounding tissue, either via bone cement or via bone ingrowth into the attachment face 3.

[0076] The attachment face 3 of the replacement member 100 is provided with a plurality of anchoring protrusions, in particular a first 101, a second 102, and a third 103 anchoring protrusion. In this exemplary embodiment, the substantially cylindrical first anchoring protrusion 101 is configured to extend substantially orthogonally from the attachment face 3.

[0077] As shown in FIGS. 3, the first anchoring protrusion 101 may also be provided with annular recesses 111. It is to be noted that in this exemplary embodiment, the anchoring protrusion 101 comprises two annular recesses 111. However, any number of recesses 111 may be provided for anchoring of the replacement member 100. As shown in FIGS. 3A-C, the recesses 111 may extend along the entire circumference of the anchoring protrusion 101. Naturally, they may also be configured to partially surround the anchoring protrusion 101.

[0078] Preferably, there is also at least a second anchoring protrusion 102 that extends from the attachment face 3 substantially parallel to the first anchoring protrusion 101. The plurality of anchoring protrusions generally extend parallel to each other into the same direction (direction of insertion).

[0079] As already discussed above, more than one anchoring protrusion prevents the replacement member 100 from rotating about a longitudinal axis of one of these protrusions.

[0080] Alternatively, only one protrusion may be provided that is at least partly not formed with a circular cross-section so that once anchored in bone tissue, the geometry of the protrusion prevents the replacement member from rotating about the longitudinal axis of the protrusion. Naturally such a configuration of a protrusion may also be provided in case of multiple protrusions. This will be described in more detail below in relation to the partial recesses 112 and 113 of the second anchoring protrusion 102 and the third anchoring protrusion 103, respectively. It should be noted that the connection between the replacement member 1 and the intermediate member 500 may also be configured in this manner.

[0081] Further, the protrusions increase the surface provided for attaching the replacement member 100 to bone tissue. This is particularly advantageous for anchoring the replacement member by ingrowth of bone tissue.

[0082] The second anchoring protrusion 102 may be provided with, for example, two partial recesses 112. These partial recesses 112 are preferably configured to face outwardly in respect to the replacement member 100 as a whole. In other words, the recesses 112 partially extending along the circumference of the anchoring protrusion 102 are directed in a radial direction away from the first anchoring protrusion 101. Similar to the above, the recesses 112 are not particularly limited to the shape depicted in FIG. 3A-C, and may, for example, be configured annularly, similarly to the recess or recesses 111 of the first anchoring protrusion 101. Also, the number of the recesses 102 is not particularly limited to the number shown in the embodiment.

[0083] Besides increasing the surface for anchoring further, any number of these recesses formed in the protrusions result in a form fit that is particularly effective when using bone cement for anchoring the replacement member 100.

[0084] Further, there may also be at least one third anchoring protrusion 103 extending from the attachment face 3 and substantially parallel to the first anchoring protrusion 101. In FIGS. 3A to 3C, two third anchoring protrusion 103 are provided with two partial recesses 113 each, which are also configured to face outwardly as previously described in relation to the second anchoring protrusion 102.

[0085] Similar to the above, the recess or recesses 103 is/are not particularly limited to the shape depicted in FIGS. 3A-C, and may, for example, be configured annularly, similarly to the recess or recesses 111 of the first anchoring protrusion 101. Likewise, the number of recesses 103 is not particularly limited to the number shown in the exemplary embodiment of FIGS. 3A-3C.

[0086] When the replacement member 100 is implanted, the second anchoring portion 102 is preferably arranged to be cranially, that is, on the side of an abduction movement of a shoulder joint. The third anchoring protrusions 103 are preferably located caudally, that is, on the side of an adduction movement and on the side opposite to the side, where the chamfered or rounded edge 9 is located.

[0087] Since the anatomy of the shoulder provides caudally more space than cranially, the embodiment shown in FIGS. 3A-C comprises one second anchoring protrusion 102 cranially and two anchoring protrusions 103 caudally. The skilled person will appreciate that the present disclosure is not limited to the depicted configuration and the numbers of anchoring protrusions 101, 102, and 103 may be varied. Nevertheless, it is to be noted that the provision of two anchoring protrusions 103 allows to position said anchoring protrusions 103 offset from the straight line defined by the anchoring protrusions 101 and 102. This offset provides additional stability for the replacement member 100, for example, against an anteversion-/retroversion movement.

[0088] As mentioned above, the direction of extension of the anchoring protrusions 101, 102, 103 is essentially parallel so that the replacement member 100 can be smoothly inserted into a plurality of correspondingly shaped parallel cavities that have been prepared within the bone tissue of a patient.

[0089] The recesses 111, 112, 113 provide space for the ingrowth of tissue and, in case of cemented replacement members, for the cement. It is therefore apparent that, while the precise shape of the recesses 111, 112, 113 is not limited, it is still advantageous to provide the recesses 112, 113, that is, the recesses of the second 102 and third 103 anchoring protrusion, at least facing radially outwards in relation to the replacement member 100. This configuration improves the mechanical resistance of the replacement member against torque, which may, for example, result from the movement of the arm, such as an adduction or abduction.

[0090] The attachment face 3 of the embodiment shown in FIGS. 3A-C is formed in a convex shape, which resembles the native shape of a joint cup, and, thus, reduces the amount of native tissue that needs to be removed before implantation of the replacement member. More specifically, only the cartilage tissue has to be removed completely, wherein the bone tissue may only be adapted to the shape of the attachment face 3.

LIST OF REFERENCE SIGNS

[0091] 1 replacement member [0092] 2 first edge [0093] 2a first portion [0094] 2b second portion [0095] 3 attachment face [0096] 4 second edge [0097] 5 joint surface [0098] 7 circumferential or peripheral face [0099] 9 chamfered or rounded edge [0100] 11 attachment structure [0101] 13 protrusion [0102] 100 replacement member [0103] 101 first anchoring protrusion [0104] 102 second anchoring protrusion [0105] 103 third anchoring protrusion [0106] 111 annular recess [0107] 112, 113 partial recess [0108] 500 intermediate member [0109] 510, 510′ fastener [0110] 513 tissue attachment face [0111] 515 first protrusion [0112] 517 second protrusion [0113] 521 device attachment face [0114] 525 first through hole [0115] 527 second through hole