A ceramic acetabular cup devoid of a separate liner comprises a part-spherical inner articulating surface and an outer surface. An inner radius at or adjacent to a rim of the cup extends to or adjacent to a surface edge of the inner articulating surface. An inner radius of the inner articulating surface defines an active arc, and an uppermost portion of the rim defines an offset datum plane. An offset is provided between an equatorial centre of the inner articulating surface and the offset datum plane. The active arc extends in a range from around 150 degrees to less than 180 degrees, and a distance between the inner articulating surface and outer surface on a straight line from the said equatorial centre and passing through the surface edge is equal to or less than 4 mm.

Off-center liners can be used with an acetabular cup in hip replacement or revision surgical procedures. The liners (of metal or plastic) can be laterally spaced from the acetabular cup, angled relative to the acetabular cup and/or have an opening that is offset relative to the axis of the acetabular cup. The liners have an orientation indicator that identifies where the liner should be impacted (e.g., impaction location or point) by the impactor to ensure the liner is impacted in a square manner relative to the acetabular cup.

The invention describes an implant for wear couples in endoprosthetics, the implant having an outer side, with an outer face, and an inner side, and a hemispherical wear region for accommodating a spherical wear partner being formed on the inner side. The aim of the invention is to reduce the height of the implant as much as possible and to ensure that, e.g., the pelvic bone does not have to be milled down as much. According to the invention, the implant is therefore designed in the form of a ring or annular structure and the outer face permits direct implantation in the body. In order to reduce friction between the spherical wear partner and the implant to a minimum, the implant has a specially designed inner geometry.

In embodiments of the invention, an implant that anchors into bone may have a bone-facing region that comprises a plurality of interconnected struts. The interconnected struts may define local features such as engagement ridges, fins, crests, a macroscopic surface-interrupting feature, a divertor structure, and sawteeth in any combination. Such features may help resist translation or rotation of the implant, and may be conducive to bone ingrowth. Parameters such as local empty volume fraction and local average strut length can be varied, even within the features, by the design of the network of struts. Struts may be tapered. Cantilever struts may also be provided, which may point in a desired direction. The pattern of struts may be specified to the level of dimensions and location of individual struts. The implant may be manufactured by additive manufacturing methods. The mesh of struts may be generated by an algorithm using Voronoi tessellation.

In embodiments of the invention, an implant that anchors into bone may have a bone-facing region that comprises a plurality of interconnected struts. The interconnected struts may define local features such as engagement ridges, fins, crests, a macroscopic surface-interrupting feature, a divertor structure, and sawteeth in any combination. Such features may help resist translation or rotation of the implant, and may be conducive to bone ingrowth. Parameters such as local empty volume fraction and local average strut length can be varied, even within the features, by the design of the network of struts. Struts may be tapered. Cantilever struts may also be provided, which may point in a desired direction. The pattern of struts may be specified to the level of dimensions and location of individual struts. The implant may be manufactured by additive manufacturing methods. The mesh of struts may be generated by an algorithm using Voronoi tessellation.

Off-center liners can be used with an acetabular cup in hip replacement or revision surgical procedures. The liners (of metal or plastic) can be laterally spaced from the acetabular cup, angled relative to the acetabular cup and/or have an opening that is offset relative to the axis of the acetabular cup. The liners have an orientation indicator that identifies where the liner should be impacted (e.g., impaction location or point) by the impactor to ensure the liner is impacted in a square manner relative to the acetabular cup.

A ceramic acetabular cup (10) devoid of a separate liner comprises a part-spherical inner articulating surface (12) for non-captively receiving a femoral head, and an outer surface (14) for enabling direct to bone fixation. An inner radius at or adjacent to a rim (22) of the cup (10) extends to or adjacent to a surface edge of the inner articulating surface (12) to prevent or reduce undesirable effects of impingement of an associated femoral head and/or neck. An inner radius of the inner articulating surface (12) defines an active arc (A) over which an in use femoral head can articulate, and an uppermost portion of the rim (22) defines an offset datum plane (D). An offset (O) between an equatorial centre (E) of the inner articulating surface (12) and the offset datum plane (D) is in a range of around 1 mm towards a pole (24) of the inner articulating surface (12) and around 3.5 mm away from the said pole (24). The active arc (A) extends in a range from around (150) degrees to less than 180 degrees, and a distance between the inner articulating surface, (12) and outer surface (14) on a straight line from the said equatorial centre (E) and passing through the surface edge is equal to or less than 4 mm.

Off-center liners can be used with an acetabular cup in hip replacement or revision surgical procedures. The liners (of metal or plastic) can be laterally spaced from the acetabular cup, angled relative to the acetabular cup and/or have an opening that is offset relative to the axis of the acetabular cup. The liners have an orientation indicator that identifies where the liner should be impacted (e.g., impaction location or point) by the impactor to ensure the liner is impacted in a square manner relative to the acetabular cup.

A ball and socket assembly including a ball component with a notch formed therein. The socket is a one-piece structure including an opening sized to receive the ball component. The ball is a capable of being inserted into the socket when the notch, cavity, or undercut is properly oriented relative to the opening of the one-piece socket.

In embodiments of the invention, an implant that anchors into bone may have a bone-facing region that comprises a plurality of interconnected struts. The interconnected struts may define local features such as engagement ridges, fins, crests, a macroscopic surface-interrupting feature, a divertor structure, and sawteeth in any combination. Such features may help resist translation or rotation of the implant, and may be conducive to bone ingrowth. Parameters such as local empty volume fraction and local average strut length can be varied, even within the features, by the design of the network of struts. Struts may be tapered. Cantilever struts may also be provided, which may point in a desired direction. The pattern of struts may be specified to the level of dimensions and location of individual struts. The implant may be manufactured by additive manufacturing methods. The mesh of struts may be generated by an algorithm using Voronoi tessellation.