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.

Prostheses, acetabular apparatuses, and methods of use are disclosed. In some embodiments, an acetabular apparatus includes an acetabular cup and an acetabular cage disposed within an interior of the acetabular cup. The acetabular cage may include a central portion including a first section and a second section rotatably coupled together, and a first flange extending from the first section and a second flange extending from the second section. The acetabular prosthesis may further include a fastener extending through each of the acetabular cup and the central portion of the acetabular cage.

A method of implanting a prosthetic stemless shoulder implant may include making an incision into a patient's shoulder area of a patient and passing a cutting instrument through a rotator cuff interval of the patient. A central portion of the native humeral head may be resected and removed so that a central void remains. The same or another cutting instrument may be inserted through the rotator cuff interval and into the central void. Medial and lateral portions of the native humeral head adjacent the central void may be resected and removed. A base of a prosthesis may be implanted into a proximal portion of the humerus after passing the base through the rotator cuff interval, and two humeral head portions may be inserted through the rotator cuff interval and coupled to the base and to one another.

A liner adapted for insertion into an acetabular shell for use in hip arthroplasty. The liner includes a concave inner surface adapted to engage a femoral head. The liner also includes an outer surface adapted to engage the acetabular shell and a rim that extends between the inner surface and the outer surface. The outer surface includes a locking section extending from the rim, a composite-curved section extending from the locking section at a first transition point, and a dome section extending from the composite-curved section, wherein at the first transition point, the composite-curved section is tangential to the locking section.

A method of implanting a prosthetic stemless shoulder implant may include making an incision into a patient's shoulder area of a patient and passing a cutting instrument through a rotator cuff interval of the patient. A central portion of the native humeral head may be resected and removed so that a central void remains. The same or another cutting instrument may be inserted through the rotator cuff interval and into the central void. Medial and lateral portions of the native humeral head adjacent the central void may be resected and removed. A base of a prosthesis may be implanted into a proximal portion of the humerus after passing the base through the rotator cuff interval, and two humeral head portions may be inserted through the rotator cuff interval and coupled to the base and to one another.

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.

A liner adapted for insertion into an acetabular shell for use in hip arthroplasty. The liner includes a concave inner surface adapted to engage a femoral head. The liner also includes an outer surface adapted to engage the acetabular shell and a rim that extends between the inner surface and the outer surface. The outer surface includes a locking section extending from the rim, a composite-curved section extending from the locking section at a first transition point, and a dome section extending from the composite-curved section, wherein at the first transition point, the composite-curved section is tangential to the locking section.

A kit for use in arthroplasty. The kit including a shell which has a shell locking section. The kit further including a liner adapted to be inserted into the shell. The liner includes an inner surface and an outer surface, wherein the inner surface is generally concave. The outer surface is adapted to engage the shell, and includes a liner locking section and a curved section. The curved section has a radius. The shell locking section and the liner locking section are adapted to engage one another. The shell locking section and the liner locking section are self-locking tapers. The curved section extends tangentially from the liner locking section at a first transition point.

A kit for use in arthroplasty. The kit including a shell which has a shell locking section. The kit further including a liner adapted to be inserted into the shell. The liner includes an inner surface and an outer surface, wherein the inner surface is generally concave. The outer surface is adapted to engage the shell, and includes a liner locking section and a curved section. The curved section has a radius. The shell locking section and the liner locking section are adapted to engage one another. The shell locking section and the liner locking section are self-locking tapers. The curved section extends tangentially from the liner locking section at a first transition point.

A liner adapted for insertion into an acetabular shell for use in hip arthroplasty. The liner includes a concave inner surface adapted to engage a femoral head. The liner also includes an outer surface adapted to engage the acetabular shell and a rim that extends between the inner surface and the outer surface. The outer surface includes a locking section extending from the rim, a composite-curved section extending from the locking section at a first transition point, and a dome section extending from the composite-curved section, wherein at the first transition point, the composite-curved section is tangential to the locking section.