Acetabular cup assembly with selected bearing

• US 6,475,243 B1
• Filed: 09/19/2000
• Issued: 11/05/2002
• Est. Priority Date: 05/22/1998
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: Sheldon, Michael B., Dong, Nicholas N. G.
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): STEWART, ALVIN J
• Application Number:
  US09/665,025
• Time in Patent Office: 777 Days
• Field of Search: 623/22.21, 623/22.24, 623/22.25, 623/22.28, 623/22.26, 623/22.23, 623/22.17, 623/22.11, 623/22.12, 623/22.13, 623/22.14, 623/22.15, 623/22.19
• US Class Current: 623/22.28
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2002/30215 Stepped cones, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30349 the male and female complementary cones being of different conicities, i.e. for reducing the contact area
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30367 with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30378 Spherically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30403 Longitudinally-oriented cooperating ribs and grooves on mating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/30487 Circumferential cooperating grooves and beads on cooperating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3054 about a connection axis or implantation axis for selecting any one of a plurality of radial orientations between two modular parts, e.g. Morse taper connections, at discrete positions, angular positions or continuous positions
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30607 Kits of prosthetic parts to be assembled in various combinations for forming different prostheses
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30662 with rotation-limiting means
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30822 : Circumferential grooves
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• CPC Class Codes: A61F 2002/3401 : with radial apertures, e.g. radial bores for receiving fixation screws
• CPC Class Codes: A61F 2002/3403 : Polar aperture
• CPC Class Codes: A61F 2002/342 : the outer shell having circumferential protrusions parallel to the equatorial plane, e.g. circumferential fins or wings
• CPC Class Codes: A61F 2002/3435 : peripheral lip, e.g. elastic lip
• CPC Class Codes: A61F 2002/344 : the inner shell having an inner hip femoral head-receiving cavity offset from its centre line
• CPC Class Codes: A61F 2002/3441 : the outer shell having an outer surface and an inner insert receiving cavity being angularly inclined with respect to the longitudinal axis of the outer surface
• CPC Class Codes: A61F 2002/3448 : Multiple cups made of three or more concentric shells fitted or nested into one another
• CPC Class Codes: A61F 2002/3462 : having a frustoconical external shape, e.g. entirely frustoconical
• CPC Class Codes: A61F 2002/3482 : Two hemispherical halves having completely different structures
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 : Necks
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0062 : Kits of prosthetic parts to be assembled in various combinations for forming different prostheses
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures

Abstract

An acetabular cup assembly allows pre-operative or interoperative selection and securement of a bearing member within a shell member of the acetabular cup assembly, the bearing member being selected from a plurality of bearing members having different characteristics, including bearing characteristics, securement characteristics, position characteristics and orientation characteristics, so as to enable a surgeon to select those characteristics most appropriate to a particular patient, as determined by a pre-operative assessment or by an evaluation of conditions encountered at an implant site during the implant procedure, and to incorporate the desired characteristics into the acetabular cup assembly with ease and economy.

Claims

1. An acetabular cup assembly for receiving a proximal end of a femoral component of a prosthetic hip implant, the femoral component including a head member and a neck member depending from the head member in a distal direction, the acetabular cup assembly having an external shell member with an internal cavity, and an internal bearing member for securement within the cavity to receive the head member of the femoral component for rotational movement within the bearing member, the internal bearing member being selected from a plurality of bearing members having different characteristics, including different securement characteristics, such that the acetabular cup assembly selectively is provided with characteristics corresponding to the characteristics of the selected internal bearing member, the acetabular cup assembly comprising:

a metallic securing member for reception within the cavity of the shell member, the securing member extending between an upper end and a lower end and including an external securing element and an internal receptor element;

an external receptor element on the bearing member, the external receptor element and the internal receptor element having interengagable structures compatible with the securement characteristics of the selected bearing member such that upon engagement of the external receptor element with the internal receptor element the internal bearing member is secured to the securing member with the lower end of the bearing member spaced upwardly a prescribed distance from the lower end of the securing member; and

an internal securing element within the cavity of the shell member, the internal securing element being essentially complementary to the external securing element of the securing member such that upon selective engagement of the external securing element with the internal securing element the securing member is secured selectively within the shell member;

the prescribed distance between the lower end of the bearing member and the lower end of the securing member being such that contact between the neck member of the femoral component and the lower end of the securing member precludes deleterious impingement of any portion of the femoral component distal of the head member upon the bearing member.

2. The invention of claim 1 wherein the internal securing element of the shell member and the external securing element of the securing member include complementary tapered securing surfaces for interlocking in response to seating engagement of the complementary securing surfaces.

3. The invention of claim 2 wherein the internal receptor element of the securing member and the external receptor element of the bearing member include complementary securing surfaces for interlocking upon seating engagement of the complementary securing surfaces.

4. The invention of claim 3 wherein the complementary securing surfaces of the external receptor element include complementary tapered surfaces for interlocking in response to seating engagement of the complementary tapered surfaces.

5. The invention of claim 4 wherein the shell member includes a lower end and an upper end, the cavity extends from the lower end toward the upper end of the shell member, and the internal securing element is located adjacent the lower end of the shell member.

6. The invention of claim 5 wherein the external securing element is located adjacent the lower end of the metallic securing. member.

7. The invention of claim 6 wherein the metallic securing member includes a ring portion adjacent the lower end and a domed portion extending between the ring portion and the upper end of the metallic securing member.

8. The invention of claim 7 wherein the shell member includes at least one depending finger extending downwardly from the lower end of the shell member, and the metallic securing member includes a flange extending laterally outwardly from the lower end of the securing member for engaging the depending finger to preclude the seating engagement of the complementary tapered securing surfaces of the shell member and the securing member, and at least one notch in the flange, the notch being configured for accepting entrance of the finger into the notch upon alignment of the notch with the finger, such alignment of the notch with the finger being accomplished upon a desired orientation and alignment of the securing member, and the bearing member therein, relative to the shell member, for enabling seating engagement of the complementary tapered surfaces with the bearing member in the desired orientation and alignment.

9. The invention of claim 1 wherein the shell member includes a lower end and an upper end, the cavity extends from the lower end toward the upper end of the shell member, the internal receptor element includes a central axis extending longitudinally between the lower end and the upper end of the shell member, the external securing element includes a central axis extending longitudinally between the lower end and the upper end of the shell member, and the central axis of the internal receptor element is offset laterally from the central axis of the external securing element.

10. The invention of claim 9 wherein the internal securing element of the shell member and the external securing element of the securing member include complementary tapered securing surfaces for interlocking in response to seating engagement of the complementary securing surfaces.

11. The invention of claim 10 wherein the internal receptor element of the securing member and the external receptor element of the bearing member include complementary securing surfaces for interlocking upon seating engagement of the complementary securing surfaces.

12. The invention of claim 11 wherein the complementary securing surfaces of the external receptor element include complementary tapered surfaces for interlocking in response to seating engagement of the complementary tapered surfaces.

13. The invention of claim 12 wherein the shell member includes at least one depending finger extending downwardly from the lower end of the shell member, and the metallic securing member includes a flange extending laterally outwardly from the lower end of the securing member for engaging the depending finger to preclude the seating engagement of the complementary tapered securing surfaces of the shell member and the securing member, and at least one notch in the flange, the notch being configured for accepting entrance of the finger into the notch upon alignment of the notch with the finger, such alignment of the notch with the finger being accomplished upon a desired orientation and alignment of the securing member, and the bearing member therein, relative to the shell member, for enabling seating engagement of the complementary tapered surfaces with the bearing member in the desired orientation and alignment.

14. The invention of claim 1 wherein the shell member includes a lower end and an upper end, the cavity extends from the lower end toward the upper end of the shell member, the internal receptor element includes a central axis extending longitudinally between the lower end and the upper end of the shell member, the external securing element includes a central axis extending longitudinally between the lower end and the upper end of the shell member, and the central axis of the internal receptor element makes an acute angle with the central axis of the external securing element.

15. The invention of claim 14 wherein the internal securing element of the shell member and the external securing element of the securing member include complementary tapered securing surfaces for interlocking in response to seating engagement of the complementary securing surfaces.

16. The invention of claim 15 wherein the internal receptor element of the securing member and the external receptor element of the bearing member include complementary securing surfaces for interlocking upon seating engagement of the complementary securing surfaces.

17. The invention of claim 16 wherein the complementary securing surfaces of the external receptor element include complementary tapered surfaces for interlocking in response to seating engagement of the complementary tapered surfaces.

18. The invention of claim 17 wherein the shell member includes at least one depending finger extending downwardly from the lower end of the shell member, and the metallic securing member includes a flange extending laterally outwardly from the lower end of the securing member for engaging the depending finger to preclude the seating engagement of the complementary tapered securing surfaces of the shell member and the securing member, and at least one notch in the flange, the notch being configured for accepting entrance of the finger into the notch upon alignment of the notch with the finger, such alignment of the notch with the finger being accomplished upon a desired orientation and alignment of the securing member, and the bearing member therein, relative to the shell member, for enabling seating engagement of the complementary tapered surfaces with the bearing member in the desired orientation and alignment.

19. The invention of claim 1 including a cushion at the lower end of the securing member for interposition between the securing member and the femoral component.

20. A shell member for use in an acetabular cup assembly having an internal bearing member for selective securement within the shell member interoperatively, the internal bearing member being selected from a plurality of bearing members having different characteristics, including different securement characteristics, such that the acetabular cup assembly selectively is provided with characteristics corresponding to the characteristics of the selected internal bearing member, the shell member comprising:

an internal cavity;

a first securing element within the cavity of the shell member, the first securing element having a first securing structure compatible with the securement characteristics of at least one of the plurality of internal bearing members; and

a second securing element within the cavity of the shell member, the second securing element having a second securing structure compatible with the securement characteristics of at least another of the plurality of internal bearing members;

the first and second securing structures being juxtaposed with one another and placed at relative locations such that the effectiveness of each of the first and second securing elements is maintained while in the presence of the other of the first and second securing elements, whereby the one and the another of the internal bearing members each is selectable for effective selective securement within the shell member to complete the acetabular cup assembly interoperatively.

21. The invention of claim 20 wherein the shell member includes a lower end and an upper end, the cavity extends from the lower end toward the upper end of the shell member, and the first and second securing elements are located adjacent the lower end of the shell member.

22. The invention of claim 21 wherein the bearing member includes a rib projecting from the bearing member, and the first securing element includes a recess in the shell member for receiving the rib of the bearing member.

23. The invention of claim 21 wherein the bearing member includes an external securing surface, and the second securing element includes an internal securing surface, the external securing surface and the internal securing surface having complementary tapered configurations for interlocking in response to seating engagement of the complementary tapered configurations.

24. The invention of claim 23 wherein the bearing member includes a rib projecting from the bearing member, and the first securing element includes a recess in the shell member for receiving the rib of the bearing member, the tapered configuration of the internal securing surface extends between an upper end and a lower end, and the recess is located intermediate the upper end and the lower end of the tapered configuration of the internal securing surface to establish an upper internal securing surface segment and a lower internal securing surface segment, with each of the upper and lower internal securing surface segments having a length between the upper and lower ends of the internal securing surface sufficient to maintain securing effectiveness throughout the internal securing surface.

25. The invention of claim 24 wherein the recess is located essentially midway between the upper and lower ends of the internal securing surface.

26. The invention of claim 25 wherein the bearing member includes an upper end and a lower end spaced in an axial direction from the upper end, and the rib includes a cross-sectional profile contour configuration having an upper section confronting the upper end of the bearing member, a lower section confronting the lower end of the bearing member, and an intermediate section between the upper and lower sections, the upper section making a first acute angle with the axial direction, the lower section making an obtuse angle with the axial direction, and the intermediate section making a second acute angle with the axial direction, the second acute angle being smaller than the first acute angle so as to establish tapered surfaces along the upper and intermediate sections for facilitating engagement of the rib within the recess, and a locking surface along the lower section for retaining the rib within the recess, while providing the rib with resistance to shearing from the bearing member.

27. A kit of component parts for assembling an acetabular cup assembly having an internal bearing member for selective securement within a shell member interoperatively, the kit comprising:

a plurality of bearing members having different characteristics, including different securement characteristics, such that the acetabular cup assembly selectively is provided with characteristics corresponding to the characteristics of a selected one of the internal bearing members;

the shell member comprising;

an internal cavity;

a first securing element within the cavity of the shell member, the first securing element having a first securing structure compatible with the securement characteristics of at least one of the plurality of internal bearing members; and

a second securing element within the cavity of the shell member, the second securing element having a second securing structure compatible with the securement characteristics of at least another of the plurality of internal bearing members;

the first and second securing elements being juxtaposed with one another and placed at relative locations such that the effectiveness of each of the first and second securing elements is maintained while in the presence of the other of the first and second securing elements, whereby the one and the another of the internal bearing members each is selectable for effective selective securement within the shell member as the selected one bearing member to complete the acetabular cup assembly interoperatively.

28. The invention of claim 27 wherein the shell member includes a lower end and an upper end, the cavity extends from the lower end toward the upper end of the shell member, and the first and second securing elements are located adjacent the lower end of the shell member.

29. The invention of claim 28 wherein the bearing member includes a rib projecting from the bearing member, and the first securing element includes a recess in the shell member for receiving the rib of the bearing member.

30. The invention of claim 28 wherein the bearing member includes an external securing surface, and the second securing element includes an internal securing surface, the external securing surface and the internal securing surface having complementary tapered configurations for interlocking in response to seating engagement of the complementary tapered configurations.

31. The invention of claim 30 wherein the bearing member includes a rib projecting from the bearing member, and the first securing element includes a recess in the shell member for receiving the rib of the bearing member, the tapered configuration of the internal securing surface extends between an upper end and a lower end, and the recess is located intermediate the upper end and the lower end of the tapered configuration of the internal securing surface to establish an upper internal securing surface segment and a lower internal securing surface segment, with each of the upper and lower internal securing surface segments having a length between the upper and lower ends of the internal securing surface sufficient to maintain securing effectiveness throughout the internal securing surface.

32. The invention of claim 31 wherein the recess is located essentially midway between the upper and lower ends of the internal securing surface.

33. An improvement in a method for implanting an acetabular cup assembly having an external shell member with an internal cavity, and an internal bearing member for securement within the cavity interoperatively, the internal bearing member being selected from a plurality of bearing members having different characteristics, including different securement characteristics, such that the acetabular cup assembly selectively is provided with characteristics corresponding to the characteristics of the selected internal bearing member, the improvement comprising the steps of:

providing a first securing element within the cavity of the shell member, the first securing element having a first securing structure compatible with the securement characteristics of at least one of the plurality of internal bearing members;

providing a second securing element within the cavity of the shell member, the second securing element having a second securing structure compatible with the securement characteristics of at least another of the plurality of internal bearing members; and

selecting the one or the another of the internal bearing members and securing the selected internal bearing member within the shell member by engaging the selected internal bearing member with the corresponding first securing element or second securing element for completion of the acetabular cup assembly interoperatively.

34. The method of claim 33 including implanting the shell member at an implant site prior to securing the selected internal bearing member within the cavity of the shell member.