Hard substance multi-hooded enarthrodial joint implant

Abstract

Multi-hooded enarthrodial joint implant has a hard substance articulating cup including a hard substance head-receiving cup having an articular surface upon which a head of a joint can articulate, and which, in general, has a margin generally about a hemisphere more or less and at least two hoods that are marginally extended continuations of superior one-half or so of cup containment of a sufficient magnitude to reduce an overall dimension of socket outlet to less than a hemisphere, which can embrace and contain the head. The head is made of a hard substance and has a truncated generally circular cross section, a truncated surface with a feature for attachment of the stem, and an opposing articular surface for articulation against the articular surface of the ceramic head-receiving cup. As an ensemble, the cup is combined with the head, typically with a stem, for a total joint implant. The hard substance may be, for example, a composite substance, a metal or a metal alloy. Either the cup or the head, but not both, may be ceramic when employed in an ensemble.

Claims

1. A system comprising: a constrained acetabular insert with its perimeter extending beyond hemisphere; a dual mobility liner with its perimeter extending beyond hemisphere; and a femoral head configured to tilt and rotate within the dual mobility liner; wherein the constrained acetabular insert comprises a plurality of tabs; wherein each of the plurality of tabs further comprises a lip; wherein the dual mobility liner comprises screw threads for receiving the lip of each of the plurality of tabs; and wherein when the screw threads are received entirely past the lip of each of the plurality of tabs, the dual mobility liner is free to tilt within the constrained acetabular insert.

2. The system of claim 1, wherein an outer surface of the dual mobility liner is, except for the screw threads, continuously spherical.

3. The system of claim 2, wherein the screw threads extend across the hemisphere of the dual mobility liner.

4. The system of claim 1, wherein the plurality of tabs of the constrained acetabular insert extend from a rim of an opening of the constrained acetabular insert.

5. The system of claim 4, wherein the plurality of tabs are circumferentially spaced apart from each other.

6. The system of claim 1, further comprising a rotation instrument configured to facilitate rotation of the dual mobility liner relative to the constrained acetabular insert.

7. The system of claim 6, wherein the dual mobility liner comprises an engagement feature configured to couple with the rotation instrument.

8. The system of claim 7, wherein the engagement feature comprises a recess for receiving a portion of the rotation instrument.

9. A system comprising: a constrained acetabular insert defining a first cavity and comprising a plurality of tabs, wherein the plurality of tabs are disposed beyond hemisphere of the constrained acetabular insert; a dual mobility liner defining a second cavity and comprising an outer surface, wherein the outer surface extends beyond hemisphere of the dual mobility liner and comprises screw threads; and a femoral head configured to tilt and rotate within the second cavity; wherein the screw threads are configured to receive the plurality of tabs; and wherein when the dual mobility liner is fully contained within the constrained acetabular insert, the dual mobility liner is able to tilt and rotate within the first cavity.

10. The system of claim 9, wherein the dual mobility liner comprises an engagement feature configured to couple with a rotation instrument.

11. The system of claim 9, wherein the screw threads extend across the hemisphere of the dual mobility liner.

12. The system of claim 9, wherein the constrained acetabular insert comprises a first rim that defines a first opening to the first cavity.

13. The system of claim 12, wherein the plurality of tabs extend from the first rim.

14. The system of claim 13, wherein the plurality of tabs are circumferentially spaced apart from each other.

15. The system of claim 12, wherein the dual mobility liner comprises a second rim that defines a second opening to the second cavity.

16. The system of claim 15, wherein with the dual mobility liner within the first cavity and with the first opening being parallel to the second opening, a portion of the outer surface of the dual mobility liner disposed within the first cavity is continuously spherical, except for the screw threads, and thus nests within inner surface of the first cavity.

17. The system of claim 15, wherein the outer surface of the dual mobility liner is continuously spherical, except for the screw threads, and thus is free of planar surfaces.

18. A method comprising: engaging a plurality of tabs of a constrained acetabular insert with screw threads on an outer surface of a dual mobility liner; and rotating the dual mobility liner relative to the constrained acetabular insert to pass the plurality of tabs entirely through the screw threads to insert the dual mobility liner within a cavity of the constrained acetabular insert, wherein once the plurality of tabs have been passed fully beyond the screw threads the dual mobility liner is configured to tilt and rotate within the constrained acetabular insert.

19. The method of claim 18, wherein the cavity of the constrained acetabular insert is a first cavity, the method further comprising coupling a femoral head within a second cavity of the dual mobility liner, wherein the femoral head is configured to tilt and rotate within the dual mobility liner.

20. The method of claim 19, wherein coupling the femoral head within the second cavity of the dual mobility liner occurs before rotating the dual mobility liner relative to the constrained acetabular insert.

Description

[0009] The drawings form part of the specification hereof. With respect to the drawings, which are not necessarily drawn to scale and in which the lining of materials in sectional views, in general, is intended to be set forth generically for the materials that are employed hereinsuch as, for example, a composite, metal or metal alloy substance, but may include a ceramic head or cup, but not both, in an ensemblethe following is briefly noted:

[0010] FIG. 1 is a perspective view of a hard substance multi-hooded enarthrodial joint implant cup of the invention for an ensemble therewith, the same being embodied as a double-hooded hard substance acetabular cup for a total conventional hip replacement implant.

[0011] FIG. 2 is a front view of the cup of FIG. 1.

[0012] FIG. 3 is a sectional view of the cup of FIG. 1, taken along 3-3 of FIG. 2.

[0013] FIG. 4 is a sectional view of the cup of FIG. 1, taken along 4-4 of FIG. 2, which is normal to 3-3 of FIG. 2.

[0014] FIG. 5 is a sectional view of another hard substance multi-hooded enarthrodial joint implant cup of the invention for an ensemble therewith, the same being embodied as a double-hooded hard substance acetabular cup for a total conventional hip replacement implant, and having angular displacement of the margin and hoods. Compare, FIG. 4.

[0015] FIG. 6 is a sectional view of another hard substance multi-hooded enarthrodial joint implant cup of the invention for an ensemble therewith, embodied as a double-hooded hard substance acetabular cup for a total conventional hip replacement implant, and having angular displacement of the margin and hoods. Compare, FIG. 5.

[0016] FIG. 7 is a front view of a securing member of the invention for an ensemble therewith, the same able to be embodied as a 6-4 ELI titanium alloy ring.

[0017] FIG. 8 is a rear view of the securing member of FIG. 7.

[0018] FIG. 9 is a side view of the securing member of FIG. 7, taken along arrow 9 in FIG. 7.

[0019] FIG. 10 is a side view of the securing member of FIG. 7, taken along arrow 10, which is normal to arrow 9 in FIG. 7.

[0020] FIG. 11 is a top view of an ensemble of the invention, which includes the cup of FIG. 1 and the securing ring of FIG. 7, without security enhancing fasteners such as screws depicted for the sake of clarity.

[0021] FIG. 12 is a sectional view of the ensemble of FIG. 11, taken along 12-12 in FIG. 11.

[0022] FIG. 13 is an exploded, perspective view of a modular head and stem arrangement for a total joint implant of the invention.

[0023] FIG. 14 is a schematic view of another hard substance multi-hooded enarthrodial joint implant cup with a modular head and stem arrangement for a total hip joint implant ensemble of the invention, and its assembly.

[0024] FIG. 15 is a sectional plan view of an ensemble such as that of FIG. 11 and as would be taken along 12-12 in FIG. 11, by which is embraced a ball head of a corresponding implant, here, the ball head of a femoral component for the total hip implant, with a modular head and stem arrangement such as illustratively depicted within FIGS. 13 and 14, two security enhancing fasteners, and a backing shell.

[0025] FIG. 16 is front view of a another hard substance multi-hooded enarthrodial joint implant cup with a modular head and stem arrangement for a shoulder joint implant of the invention.

[0026] The invention can be further understood by the following additional detail, which, as with the foregoing, may be read in view of the drawings. Such is to be taken in an illustrative and not necessarily limiting sense.

[0027] The principles of the invention can be applied to provide a hard substance multi-hooded enarthrodial joint implant cup ensemble, or parts thereof, for any suitable enarthrodial joint, or other generally corresponding pivoting joint, to include the hip, shoulder, thumb or finger. The hip and shoulder are illustratively depicted.

[0028] Any suitable material may be employed. Generally, materials are biocompatible. Apart from confines of an ensemble, the hard substance is not ceramic. Thus, material for the cup and any corresponding modular head for receipt in the cup may be selected from any suitable rigid, hard substance, to include any suitably rigid, strong materials that may include such plastics as nylons, polycarbonates or epoxies; composites; such metals as titanium or cobalt; and such metal alloys as stainless steel, titanium-vanadium-aluminum, cobalt-chrome, and so forth. Additional component parts, if present, are made of suitable materials. For example, a backing shell or other part may be made of a suitable composite, metal, or metal alloy such as aforesaid, for example, a 6-4 ELI titanium alloy; a stem for the modular head and stem assembly may be made of a suitable composite, metal, or metal alloy, for example, a cobalt-chrome alloy, stainless steel, and so forth. If not metal, the hard substance can have hardness properties of or akin to metal or ceramic. If ceramic is employed, say, as a cup or its corresponding head, but not both, in a joint implant ensemble, it may be any suitable ceramic, for instance, a ceramic such as an alumina or a zirconia, for example, MgOTTZ such as in Serafin, Jr. et al., U.S. Pat. No. 9,259,508 B2.

[0029] The hoods of the cup embrace the head of a joint greater than the circular cross section, for example, as a truncated spherical ball head greater than a hemisphere, in general, at least about their areas of contact with the head. Thus, in general, the hoods are marginally extended continuations of the superior one-half or so of the cup containment of a sufficient magnitude to reduce the overall dimension of the socket outlet to less than a half a circle in cross section, say again, a hemisphere in the case of a truncated spherical ball head. The truncated head is slid sideways into the cup into the embrace of the hoods. After insertion of the head into the hooded cup, the head is rotated in relation to the cup so as to bring its truncated surface into position to have the corresponding stem attached. Then any securing member may be brought into position.

[0030] More than one hood is required in the practice of the present invention. Thus, for instance, two, three, four or more hoods may be employed, say, with two opposing hoods; with three hoods equidistant about the margin of the cup and margin segments and hoods having about the same arc lengths, or with hoods having less of an arc length than the margins such as from about to of the are length of the margins; with three hoods not equidistant about the margin and themselves having the same arc lengths, or with one having a larger arc length opposed by two with lesser arc lengths; with four hoods equidistant about the margin and margin segments and hoods having about the same arc lengths, or with hoods having less of an arc length than the margins; with four hoods about the margin, two of the hoods in a set opposing two of the hoods in another set with greater margins between the two sets of hoods than between each hood in a set, or in an asymmetric arrangement, and so forth. Advantageously, the hard substance multi-hooded enarthrodial joint implant is embodied as a double-hooded cup, which may be present without the securing member.

[0031] Any suitable configuration for the modular head and stem may be employed. In general, however, there is a head component separate from but attachable with a stem component. The attachment may be carried out by any suitable method or means such as one or more of gluing, screwing, friction fitting, pressure fitting, and so forth. A tapered receptacle into which a corresponding trunnion is inserted may be employed. For example, the head may contain the tapered receptacle, for example, a conically or frustoconically tapered receptacle, with the corresponding trunnion being provided on a stem extremity. A self-locking taper such as, for example, a Morse taper, may be employed.

[0032] As optional further securement, the securing member provides for resistance against any likelihood, if any, of cracking, fracture, or other failure of the ceramic such as by an application of unusually great outwardly displacing force. Preferably, the securing member secures at least two hoods, and may secure each of the hoods present with the cup. The securing member may take any suitable form, including that of a ring or a U-shaped or a horseshoe-shaped member.

[0033] Additional parts or components may be present. For instance, a backing shell may be present, into which the cup is inserted, or an implant bone insert such as in Serafin, Jr. et al., U.S. Pat. No. 7,892,289 B2, may be provided to the head.

[0034] With respect to the drawings, hard substance joint head 20 articulates within multi-hooded enarthrodial joint implant cup 50 in ensemble 100. Securing member 70 may be present.

[0035] The joint head 20made, for example, of a composite such as a fiber reinforced polymer composite, which may be a carbon fiber-polycarbonate, a carbon fiber-polysulfone, a carbon fiber-polyetherketone, a polyaramid fiber-polycarbonate, a polyaramid fiber-polysulfone, or a polyaramid fiber-polyetherketone, and so forth and the like, or of a cobalt-chrome alloy, desirably a cobalt-chrome-molybdenum alloy, which may be a forged alloy of cobalt-chromium to ASTM F-799 specifications, or of a non-magnetic cobalt-chromium-molybdenum alloy as a wrought powder metallurgy product such as BioDur CCM Plus alloy (Carpenter Technology Corp.), U.S. Pat. No. 5,462,575, or which may be made to another specification such as ASTM F1537 or ASTM F75, or a stainless steel, and so forth and the like, or perhaps a ceramic when configured in an ensemble with a cup 50 that is not a ceramicis in a shape of a truncated sphere; has articulation surface 20A, blind frustoconical hole 20H with Morse taper in truncated surface 20S and central truncation distance 20T greater than the head radius, say, about from 60%, 65% or 70% to 75%, 80% or 85% of the head diameter; and is connectable to stem 21. For instance, the stem 21, which may be made of a material that the joint head 20 is made or of a different material selected from the above or of another substance, includes trunnion 21T having corresponding Morse taper, which is inserted into the hole 20H of the head 20 for insertion into the medullary canal of the resected upper femur of a human patient.

[0036] The cup 50 made of a hard substance such as may be employed for the head 20for example, a suitable composite, metal or metal alloy to include as exemplified as aforesaid, or perhaps a ceramic when configured in an ensemble with a head 20 that is not a ceramicincludes articular surface 51; body 52; back 53, which may be for facing a backing shell interior when inserted into backing shell 60, or back 53, which is for interfacing resected bone when implanted into the patient; margins 54; and hoods 55, which may have arcs, for example, arc 55A of about sixty-five degrees and arc 55A of about seventy degrees, one or more of which may be provided in advance or at the surgical site with ring tab registering side hole 55H and/or pilot hole 55P. The cup 50 also may include circumferential lip 56, which is essentially or to a great extent flat, being essentially or to a great extent parallel with a central axis, and which, with the margins 54 and/or hoods 55, may be level (FIGS. 1-4, 11, 12, 15); be angled at angle A, say, about from five to twenty degrees, for example, about ten degrees (FIGS. 5, 6); or be absent, wholly or essentially (FIG. 14). The cup 50 may also include fastening aid 57 such as porous coating 57C; circumferential groove 57G into which circumferential ring 57R may be positioned such as by heating to expand the ring 57R, positioning it over and then cooling it to shrink into the groove 57G such as found in Serafin, Jr. et al., U.S. Pat. No. 9,308,674 B1, with the ring 57R able to carry a supply of porous coating 57C; and circumferential slot 57S for engagement through auspices of a locking ring with the backing shell 60 made, for example, of 6-4 ELI titanium alloy per ASTM F-136 specifications, which has complimentary fastening aid 67, here, a circumferential protrusion. The backing shell 60 also may have, among other things, optional cox-comb 68 for insertion into bone stock, notably in the case of a total hip joint replacement implant, and/or have a roughened or the porous coated surface 57C for interfacing with resected bone surface and promoting bone ingrowth to stabilize the implant. A backing shell 60 for the shoulder may also have arm(s) 235 such as first arm 235A for fastening to the acromion, which may be assisted by providing hole 235HA for a bone screw, and/or second arm 235C for fastening to the coracoid process. Surgical cement such as polymethylmethacrylate may be used.

[0037] The optional securing member 70 made, for example, of cobalt-chrome alloy to ASTM F-799 specifications or to more or less demanding standards, and generally in the shape of a ring, includes ring body 72 with marginal arcs 74 and hood braces 75 that include bevel 75B, cover 75C, and perforations 75P, which may take the form of holes. Engagement tabs 76 are biased inwardly, and have edges 76E that may engage the material of the cup 50 about the hood 55 and side hole 55H, which may occur slightly above any lip 56, so as to help secure the ring 70 to the cup 50. In conjunction with or in lieu of the tabs 76 can be side holes 76H. Added fasteners 77 such as screws may be provided for further security, for example, which may be passed through the perforations and/or holes 75P, 76H.

[0038] The present invention is thus provided. Various feature(s), part(s), subcombination(s) and combination(s) may be employed with or without reference to other feature(s), part(s), subcombination(s) or combination(s) whereof, and numerous adaptations and modifications can be effected within its spirit, the literal claim scope of which is particularly pointed out as follows: