# US 8,771,366 B2 · Mobile bearing hip assembly having decoupled motion along multiple axes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,366 B2 - Document ID: US8771366B2 - Status: Granted - Kind: B2 - Application number: 13/435,514 - Filed: 2012-03-30 - Published: 2013-10-03 - Granted: 2014-07-08 - Earliest claimed: 2012-03-30 - Assignees: DePuy Synthes Products, Inc. - Applicants: Dustin R. Whitaker; Todd D. Render; Matthew R. Dressler - Inventors: Dustin R. Whitaker; Todd D. Render; Matthew R. Dressler - Web page: https://patentgrep.com/patent/US8771366B2 ## CPC - A61F 2/34: Acetabular cups - A61F 2/32: for the hip - A61F 2/3601: {for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices (non-prosthetic internal fixation devices for the femoral head or neck A61B17/74)} - A61F 2/3609: {Femoral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic femoral shafts (A61F2/3601 takes precedence)} - A61F 2002/30354: {Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis} - A61F 2002/30364: {Rotation about the common longitudinal axis} - A61F 2002/30635: {Cardan or gimbal joints} - A61F 2002/30652: {Special cut-outs, e.g. flat or grooved cut-outs} - A61F 2002/30662: {with rotation-limiting means} - A61F 2002/3208: {Bipolar or multipolar joints, e.g. having a femoral head articulating within an intermediate acetabular shell whilst said shell articulates within the natural acetabular socket or within an artificial outer shell} - A61F 2002/3216: {tripolar} - A61F 2002/3403: {Polar aperture} - A61F 2002/3412: {with pins or protrusions, e.g. non-sharp pins or protrusions projecting from a shell surface} - A61F 2002/3448: {Multiple cups made of three or more concentric shells fitted or nested into one another} - A61F 2002/345: {the inner and outer (hemi)spherical surfaces of a shell, e.g. an intermediate shell, having distinct centres of rotation, both located on the centre line of the shell} - A61F 2310/00011: Metals or alloys - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) ## Abstract An acetabular hip implant includes an acetabular shell component, a first insert secured to the acetabular shell component, a second insert secured to the first insert, and a femoral head configured to be secured to the second insert. The first insert is permitted to rotate relative to the acetabular shell about a first axis, the second insert is permitted to rotate relative to the first insert about a second axis, and the femoral head is permitted to rotate relative to the second insert about a third axis. ## Claims ### Claim 1 An acetabular hip implant, comprising: an acetabular shell component configured to be implanted within an acetabulum of a patient, a first insert secured to the acetabular shell component such that the first insert is (i) permitted to rotate relative to the acetabular shell component about a first axis, and (ii) prevented from rotating relative to the acetabular shell component about a second axis and a third axis, the first insert having a first set of separate and discrete opposing flats defined in its inner surface on opposing sides of the first insert, a second insert secured to the first insert such that the outer surface of the second insert contacts the inner surface of the first insert, the second insert having a second set of separate and discrete opposing flats defined in its outer surface on opposing sides of the second insert, and wherein the second set of opposing flats contact the first set of opposing flats defined in the inner surface of the first insert such that the second insert is (i) permitted to rotate relative to the first insert about the second axis, and (ii) prevented from rotating relative to the first insert about the first axis and the third axis, the second insert having a third set of separate and discrete opposing flats defined in its inner surface on opposing sides of the second insert, and a femoral head configured to be secured to a femoral stem, the femoral head being secured to the second insert such that the outer surface of the femoral head contacts the inner surface of the second insert, the femoral head having a fourth set of separate and discrete opposing flats defined in its outer surface on opposing sides of the femoral head, and wherein the fourth set of opposing flats contact the third set of opposing flats defined in the inner surface of the second insert such that the femoral head is (i) permitted to rotate relative to the second insert about the third axis, and (ii) prevented from rotating relative to the second insert about the first axis and the second axis. ### Claim 2 (depends on 1) The acetabular hip implant of claim 1, wherein the first and second sets of opposing flats are parallel to one another, the third and fourth sets of opposing flats are parallel to one another, and the first and second sets of opposing flats are orthogonal to the third and fourth sets of opposing flats. ### Claim 3 (depends on 1) The acetabular hip implant of claim 1, wherein the acetabular shell component comprises a polymeric liner locked to a metal shell. ### Claim 4 (depends on 1) The acetabular hip implant of claim 1, wherein the acetabular shell component comprises a polymeric liner molded to a metal shell. ### Claim 5 (depends on 1) The acetabular hip implant of claim 1, wherein the acetabular shell component includes a metal shell having an inner surface lined with a polymeric material, the first insert and the femoral head are made of metal, and the second insert is made of a polymeric material. ### Claim 6 (depends on 1) The acetabular hip implant of claim 1, wherein the acetabular shell component comprises a protrusion received into a recess in the first insert to allow rotation about the first axis and prevent rotation about the second axis or the third axis. ### Claim 7 (depends on 1) The acetabular hip implant of claim 1, wherein the first axis is orthogonal to the second axis and the third axis. ### Claim 8 (depends on 7) The acetabular hip implant of claim 7, wherein the second axis is orthogonal to the third axis. ### Claim 9 An acetabular hip implant, comprising: an acetabular shell component configured to be implanted within an acetabulum of a patient, the acetabular shell component comprising a polymeric liner, a metal insert secured to the acetabular shell component such that the metal insert is (i) permitted to rotate relative to the acetabular shell component about a first axis, and (ii) prevented from rotating relative to the acetabular shell component about a second axis and a third axis, the metal insert having a first set of isolated diametrically opposed flats defined in an inner surface on opposing sides of the metal insert, a polymeric insert secured to the metal insert such that the outer surface of the polymeric insert contacts the inner surface of the metal insert, the polymeric insert having a second set of isolated diametrically opposed flats defined in an outer surface on opposing sides of the polymeric insert, the polymeric insert being (i) permitted to rotate relative to the metal insert about the second axis, and (ii) prevented from rotating relative to the metal insert about the first axis and the third axis, the polymeric insert having a third set of isolated diametrically opposed flats defined in an inner surface on opposing sides of the polymeric insert, and a metallic femoral head configured to be secured to a femoral stem, the femoral head being secured to the polymeric insert such that the outer surface of the femoral head contacts the inner surface of the polymeric insert, the femoral head having a fourth set of isolated diametrically opposed flats defined in an outer surface on opposing sides of the femoral head, the femoral head being (i) permitted to rotate relative to the polymeric insert about the third axis, and (ii) prevented from rotating relative to the polymeric insert about the first axis and second axis. ### Claim 10 (depends on 9) The acetabular hip implant of claim 9, wherein the acetabular shell component comprises a protrusion received into a recess in the metal insert to allow rotation about the first axis and prevent rotation about the second axis and the third axis. ### Claim 11 (depends on 9) The acetabular hip implant of claim 9, wherein the metal insert has a first set of opposing flats defined in its inner surface and the polymeric insert has a second set of opposing flats defined it its outer surface which contact the first set of opposing flats defined in the inner surface of the metal insert to permit rotation of the polymeric insert relative to the metal insert about the second axis and prevent rotation of the polymeric insert relative to the metal insert about the first axis and the third axis. ### Claim 12 (depends on 11) The acetabular hip implant of claim 11, wherein the polymeric insert has a third set of opposing flats defined in its inner surface and the metallic femoral head has a fourth set of opposing flats defined in its outer surface which contact the third set of opposing flats defined in the inner surface of the second insert to permit rotation of the femoral head relative to the polymeric insert about the third axis and prevent rotation of the femoral head relative to the polymeric insert about the first axis and the second axis. ### Claim 13 (depends on 12) The acetabular hip implant of claim 12, wherein the first and second sets of opposing flats are parallel to one another, the third and fourth sets of opposing flats are parallel to one another, and the first and second sets of opposing flats are orthogonal to the third and fourth sets of opposing flats. ### Claim 14 (depends on 9) The acetabular hip implant of claim 9, wherein the acetabular shell component comprises a polymeric liner locked to a metal shell. ### Claim 15 (depends on 9) The acetabular hip implant of claim 9, wherein the acetabular shell component comprises a polymeric liner molded to a metal shell. ### Claim 16 (depends on 9) The acetabular hip implant of claim 9, wherein the first axis is orthogonal to the second axis and the third axis. ### Claim 17 (depends on 16) The acetabular hip implant of claim 16, wherein the second axis is orthogonal to the third axis. ### Claim 18 An acetabular hip implant, comprising: an acetabular shell component configured to be implanted within an acetabulum of a patient, a first insert secured to the acetabular shell component such that the first insert is (i) permitted to rotate relative to the acetabular shell component about a first axis, and (ii) prevented from rotating relative to the acetabular shell component about any other axis, including a second axis and a third axis, the first insert having a first set of opposing flats defined in its inner surface, a second insert secured to the first insert such that the outer surface of the second insert contacts the inner surface of the first insert, the second insert having a second set of opposing flats defined in its outer surface which contact the first set of opposing flats defined in the inner surface of the first insert such that the second insert is (i) permitted to rotate relative to the first insert about the second axis, and (ii) prevented from rotating relative to the first insert about any other axis, including the first axis or the third axis, the second insert having a third set of opposing flats defined in its inner surface, wherein each flat of the first and second sets of opposing flats is semi-circular and midpoints of a non-circular edge of each of the flats of the first and second sets of opposing flats define the second axis, and a femoral head configured to be secured to a femoral stem, the femoral head being secured to the second insert such that the outer surface of the femoral head contacts the inner surface of the second insert, the femoral head having a fourth set of opposing flats defined in its outer surface which contact the third set of opposing flats defined in the inner surface of the second insert such that the femoral head is (i) permitted to rotate relative to the second insert about the third axis, and (ii) prevented from rotating relative to the second insert about any other axis, including the first axis or the second axis, wherein each flat of the third set of opposing flats is semi-circular, each flat of the fourth set of opposing flats is semi-circular, midpoints of a non-circular edge of each of the flats of the third set of opposing flats and centerpoints of each of the flats of the fourth set of opposing flats define the third axis. ### Claim 19 (depends on 18) The acetabular hip implant of claim 18, wherein the first and second sets of opposing flats are orthogonal to the third and fourth sets of opposing flats. ### Claim 20 (depends on 18) The acetabular hip implant of claim 18, wherein the first axis is orthogonal to the second axis and the third axis; and the second axis is orthogonal to the third axis. ### Claim 21 An acetabular hip implant, comprising: an acetabular shell component configured to be implanted within an acetabulum of a patient, a first insert secured to the acetabular shell component such that the first insert is (i) permitted to rotate relative to the acetabular shell component about a first axis, and (ii) prevented from rotating relative to the acetabular shell component about a second axis and a third axis, the first insert having a first flat defined in its inner surface, a second insert secured to the first insert such that the outer surface of the second insert contacts the inner surface of the first insert, the second insert having a second flat defined in outer surface which contacts the first flat defined in the inner surface of the first insert such that the second insert is (i) permitted to rotate relative to the first insert about the second axis, and (ii) prevented from rotating relative to the first insert about the first axis and the third axis, the second insert having a third flat defined in its inner surface, wherein each of the first and second flats forms at least a partial circle and centerpoints of each partial circle define the second axis, and a femoral head configured to be secured to a femoral stem, the femoral head being secured to the second insert such that the outer surface of the femoral head contacts the inner surface of the second insert, the femoral head having a fourth flat defined in its outer surface which contacts the third flat defined in the inner surface of the second insert such that the femoral head is (i) permitted to rotate relative to the second insert about the third axis, and (ii) prevented from rotating relative to the second insert about the first axis and the second axis, wherein each of the third and fourth flats forms at least a partial circle and centerpoints of each partial circle define the third axis. ### Claim 22 (depends on 21) The acetabular hip implant of claim 21, wherein the first and second flats are parallel to one another, the third and fourth flats are parallel to one another, and the first and second flats are orthogonal to the third and fourth flats. ### Claim 23 (depends on 21) The acetabular hip implant of claim 21, wherein the acetabular shell component comprises a polymeric liner locked to a metal shell. ### Claim 24 (depends on 21) The acetabular hip implant of claim 21, wherein the acetabular shell component comprises a polymeric liner molded to a metal shell. ### Claim 25 (depends on 21) The acetabular hip implant of claim 21, wherein the acetabular shell component includes a metal shell having an inner surface lined with a polymeric material, the first insert and the femoral head are made of metal, and the second insert is made of a polymeric material. ### Claim 26 (depends on 21) The acetabular hip implant of claim 21, wherein the acetabular shell component comprises a protrusion received into a recess in the first insert to allow rotation about the first axis and prevent rotation about the second axis and the third axis. ### Claim 27 (depends on 21) The acetabular hip implant of claim 21, wherein the first axis is orthogonal to the second axis and the third axis. ### Claim 28 (depends on 27) The acetabular hip implant of claim 27, wherein the second axis is orthogonal to the third axis. ### Claim 29 (depends on 21) The acetabular hip implant of claim 21, wherein the acetabular shell component and second insert are metallic and the first insert and femoral component are polymeric.