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EP-3741329-B1 - BEARING FIXATION

EP3741329B1EP 3741329 B1EP3741329 B1EP 3741329B1EP-3741329-B1

Inventors

  • SMITH, AARON P.

Dates

Publication Date
20260506
Application Date
20140206

Claims (13)

  1. A system for an acetabular prosthesis to fix a bearing liner (30) within a shell, comprising: a shell member (20) having an exterior configured to engage an anatomy and a concave interior surface (50) extending from a shell rim to a shell apex, an engagement groove (60) is defined through the concave interior surface; and a bearing liner (30) having an exterior wall surface (70) configured to be received within the concave interior of the shell member (20), the exterior wall surface (70) extending from a rim (74) of the bearing liner towards an apex (76) of the bearing liner along a substantially continuous curve, an asymmetrical axial fixation projection (90) extending from the substantially continuous curve of the exterior wall surface (70); wherein the asymmetrical axial fixation projection (90) has a first configuration where a volume of material of the asymmetrical axial fixation projection (90) is biased towards the apex of the bearing liner (30), wherein the asymmetrical axial fixation projection (90) is configured to be engaged in the engagement groove (60) of the shell to engage the bearing liner (30) within the concave interior of the shell in a locking configuration that is deformed from the first configuration due to insertion into the shell (20) and engaging the engagement groove (60) in a second configuration, characterised in that the asymmetrical axial fixation projection (90) includes a first projection surface (102) extending from the exterior surface (70) substantially perpendicular to a central axis (100) of the liner (30) and having a surface end a first distance from the exterior surface and positioned a first distance from the rim of the liner, wherein the asymmetrical axial fixation projection (90) further includes at least one second surface (110) extending towards the central axis (100) at an acute angle relative to the first projection surface (102) and positioned a second distance from the rim, wherein the second distance is less than the first distance.
  2. The system of Claim 1, wherein the groove (60) is substantially continuous around the concave interior surface.
  3. The system of Claim 1, wherein the axial fixation projection is discontinuous around the exterior of the bearing liner.
  4. The system of any of Claims 1-3 wherein the axial fixation projection is deformable to permanently move a material forming the axial fixation projection to bias the volume of material between the mid-line and a rim of the bearing liner.
  5. The system of any of Claims 1-4 wherein the material of the axial fixation projection does not compress or collapse but is mobile under the force of insertion of the liner into the shell.
  6. The system of Claim 1 wherein at least 51 percent of the material that forms the axial projection is between a midline of the axial projection and the apex of the bearing;
  7. The system of Claim 6, wherein the first projection surface is substantially perpendicular to a bearing liner axis extending from the apex past the rim.
  8. The system of Claim 6 or Claim 7, wherein the rim defines a bearing plane and the bearing liner axis is substantially perpendicular to the bearing plane and intersects the apex.
  9. The system of any of Claims 6-8, wherein the concave interior is substantially hemispherical.
  10. The system of any of claims 1-9, further comprising a proximal femoral member configured to be implanted into a femur to articulate within the positioned bearing liner.
  11. The system of any of claims 1-10, wherein the at least one second surface includes a plurality of second surfaces that together extend from an exterior end of the first projection surface to the substantially continuous curve of the exterior surface of the bearing liner.
  12. The system of any of claims 1-11, wherein the bearing liner and the axial projection are formed as one unitary piece.
  13. The system of any of claims 1-12, wherein in the first configuration the axial fixation projection has a cross-section shape of a triangle.

Description

FIELD The subject disclosure is related to fixing a deformable member to a second member, and particularly to fixing a liner to a shell. The closest prior art is document US 6334875 B1, which defines the preamble of claim 1. BACKGROUND This section provides background information related to the present disclosure, which is not necessarily prior art. A subject can have a portion replaced with a replacement member. For example, a human patient subject can have a portion of the anatomy replaced with a prosthetic member. The reason for the replacement can be due to injury, disease, or other failing of the natural anatomy. A prosthetic member can be used to replace a portion of the anatomy to substantially recreate or mimic the natural anatomy and physiology. For example, an acetabular prosthesis can be positioned in a prepared acetabulum of a patient to achieve a substantially natural or selected interaction of a femur and an acetabulum. It is understood in a complete or total hip arthroplasty that a proximal femoral portion may also be replaced. An acetabular prosthesis can include a shell component that contacts a pelvis within an acetabulum. The shell can either interact with the natural femur or with a proximal femoral prosthesis directly, or a bearing can be placed in the shell. A bearing can be fixed in the shell using a separate element that is positioned between the bearing and the shell, such as with the RINGLOC® sold by Biomet, Inc. US 2009/0088865 A1 discloses a modular hip implant that includes a base member that is to be attached to a pelvic bone, and a cup for accommodating a hip joint prosthesis. The base member and/or the cup include adjustment means for adjusting the position of the cup relative to the base member. The invention allows the inclination and anteversion to be adjusted by arranging the cup in the base. SUMMARY This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. The present invention provides a system for an acetabular prosthesis to fix a bearing liner within a shell, as defined in claim 1. Further optional features of the invention are defined in the dependent claims. An acetabular prosthesis can be positioned in a patient to replace an acetabulum that is damaged or defective. The acetabular prosthesis can be placed in the patient after properly preparing the acetabulum to receive the acetabular prosthesis. The acetabular prosthesis can generally be formed of at least two pieces, including an external shell that is positioned in contact or cemented to the acetabulum of the pelvis and a bearing liner (also referred to herein alone as a liner or bearing) that is positioned and selectively fixed within the shell. Both the shell and the liner can include convex exterior surfaces and concave interior surfaces. The convex exterior surface of the shell can engage the bone of the pelvis and the convex exterior of the liner can engage the concave interior of the shell. The concave interior of the liner can then articulate relative to a proximal femur portion. The proximal femur can be a prosthetic member or natural proximal femur. The liner can be engaged to the shell with an engagement portion defined by the liner. The engagement portion defined by the liner may engage and/or interact with the internal surface of the shell to selectively deform the liner during insertion of the liner into the shell. The engagement portion of the liner may then engage or be received by a depression formed within the shell. Once engaged with the depression the liner is substantially fixed to the shell for the purpose of the implantation. Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. Fig. 1 is an exploded view of a shell and bearing liner, according to various embodiments;Fig. 2 is a cross-section view of the shell of Fig. 1;Fig. 3 is a cross-section view of the bearing liner of Fig. 1;Fig. 4 is a detail cross-section view of an engagement portion taken from Fig. 3;Fig. 5 is a detail cross-section view of an engagement portion, according to an alternative example;Fig. 6 is a detail cross-section view of an engagement portion, according to various embodiments;Fig. 7A is a detail cross-section view of the bearing liner being inserted into the shell;Fig. 7B is a detail cross-section view of the bearing liner seated in the shell;Fig. 7C is a detail cross-section view from Fig. 7B; andFig. 8 is an environmental view of the shell and bearing liner relative to a subject. Corresponding reference numerals indicate correspondi