Modular joint

Basic implantable joint is adapted such that addable component(s) thereto can be added to the basic joint without removal of the joint from the site to which it can be initially implanted to provide a modular joint. Other modular features to a basic implantable joint are provided as well. The modular joint can be, for example, that of the knee and include a basic, implantable femoral component, with the addable component(s) able to be added inter-condylarly, which, for example, can include an insertable rotation device with a swingable, depending male type part; intramedullary spike and/or posterior stabilizing stop.

FIELD

The present invention concerns a modular joint. In a particular embodiment thereof, it concerns a prosthetic knee joint or component(s) therefor.

BACKGROUND

Various artificial joints and parts thereof are known.

A particularly useful artificial joint is disclosed by Goodman et al., U.S. Pat. No. 5,766,257 (Jun. 16, 1998). The same has natural load transfer.

A certain level of modularity exists among some known joints. For example, with total conventional hip prostheses, variously sized ceramic heads may be available for fixation to a femoral stem component. In the particular field of knee prostheses, it is known to provide insertable or thread-in, long, intramedullary spikes and adaptations therefor, in both femoral (proximal-facing adaptation) and tibial (distal-facing adaptation) components; and short, condyle-backing femoral spikes. However, such, in general, are not exchangeable after implantation, unless, for instance, the prosthesis would be removed and altered following its removal, which could have a profound, serious, negative impact on the patient.

It is always desirable to minimize the extent of surgical invasion and its potential for complications arising therefrom. See, e.g., Goodman et al.

SUMMARY

In general, the present invention provides a modular joint comprising a basic implantable joint adapted such that addable component(s) thereto can be added to the basic joint without removal of the joint from the site to which it can be initially implanted. Other modular features to a basic implantable joint are provided as well. In a particular, preferred embodiment, the modular joint is for the knee, for instance, comprising a basic, implantable femoral component, with the addable component(s) able to be added inter-condylarly, which, for example, can include an insertable rotation device with a swingable, depending male type part; intramedullary spike and/or posterior stabilizing stop.

The invention is useful in arthroplasty.

Significantly, by the present invention, an adaptable, versatile modular joint is provided. Even after implantation of the basic joint, addable component(s) can be added without removal of the basic joint, as may be required by the condition of the patient. Thus, surgical invasion from a future revision may be kept to a minimum, while the physician is provided with a series of progressive options in arthroplastic treatment.

Numerous further advantages attend the invention.

ILLUSTRATIVE DETAIL

The invention can be further understood through the present detail, which may be read in view of the drawings. Such is to be taken in an illustrative, and not necessarily limiting, sense.

The complete specifications of the application No. 60/123,383 of Serafin, Jr., and the U.S. Pat. No. 5,766,257 to Goodman et al., are incorporated herein by reference.

In reference to the present drawings, the modular joint of the present invention is depicted for purposes of illustration as a left knee prosthesis for a human being, or as addable components for the prosthesis. A corresponding joint for the right human knee could be a mirror image of the left. Other prostheses, especially other ginglymous type joints, for example, the elbow or knuckles, may be provided by appropriate analogy to the knee in the practice of the invention. Modular joints of the invention also may be provided with suitable modification for implantation in animals. Each patient is different, and thus, each may be custom fitted. Joints of the invention may be provided for mechanical or robotics applications as well. Accordingly varied can be the joint designs, shapes, and sizes, and the materials employed in the practice of the invention.

With more particular respect to the present drawings, a modular joint component can be, say, in the form of a box and include receiving housing 1 which can have opposing (side) walls 2 , top 3 , and another insert restraining (front) wall 4 , which may be opposed or not by another wall. Hole(s) may be provided in the walls, for example, top hole 3 H and/or posterior stabilizing member accommodating hole 3 P, which may be supported with proximal top flange 3 F and side wall flange 2 F, respectively ( FIG. 13 ) or not be supported beyond that which the top wall 3 simply provides (FIG. 14 ); and addable module securing screw hole 4 H ( FIGS. 4 , 5 & 15 ) which may otherwise be not threaded, say, for insertion of a pin rather than a set screw 36 . As another possible option, channels or slots such as channel 2 c may be provided in opposing walls 2 , and an axle or rod, for instance, posterior stabilizing rod 35 , may be guided into place near the top 3 of the housing 1 and secured there by insertion of screws or pegs, for instance, set screw 36 , into hole 2 H (FIG. 4 ). As is known in the art, a hole or channel may be capped with a suitable closure (not illustrated) such as a polyethylene cap when not taken advantage of. Preferably, the walls 2 are tapered, for instance, for a Browne & Sharpe taper, say, with a 1.5- to 2-degree angle 2 X. Addable modules 30 ( 35 , 37 , 50 ) beneficially correspond to the housing 1 shape. Although a boxlike housing 1 and boxlike addable modules 30 are depicted, other shapes may be employed. For instance, the addable, modular box may be round, say with one flat side to keep the box from shifting. Such an addable box is advantageously inserted into a correspondingly shaped receptacle, say, in a femoral component implant for the knee. Returning to the present drawings, the housing 1 may have substantially planar walls ( FIGS. 1-3 ) or have one or more walls in planar parts joined at an angle such as with the wall 4 ( FIGS. 4 & 5 ) which has lower portion 4 L and upper portion 4 U. Corresponding addable modules 30 may be selected to conform to these housings 1 . Compare, FIGS. 1 , 3 , 6 , 7 , 13 & 15 versus FIGS. 4 , 5 & 10 - 12 . Preferably, the addable component(s) can be added after the basic joint has been implanted in the patient without the removal of the joint. Among such, desirably, the addable component(s) are able to be added inter-condylarly, which, for example, can include the inferiorly insertable rotation device with a swingable, depending male type part 50 ( FIGS. 1-3 , 6 , 7 & 10 - 12 ); intramedullary femoral spike 37 ( FIG. 14 ) and/or posterior stabilizing stop 35 (FIG. 15 ). In the case of the latter, as is known in the art, the tibial component is provided with a spine, peg, post, or other hindering structure, for example, as part of a tibial tray liner, to be thrust up between the condyles so that, when the stop 35 contacts the upstanding tibial member, anterior sublaxation or dislocation during flexion of the knee is precluded. An addable component, which may be added after the initial surgery, also may include the simple expedient of inserting a rod (not illustrated) through an available opening such as hole 3 H ( FIGS. 13 & 14 ) or open hole 27 H ( FIG. 16 ) in an implanted basic joint to help set a postoperative fracture, or employment of a superiorly insertable, threadable tibial intramedullary spike 27 (FIG. 16 ).

In general, the basic femoral component in addition to the addable component adaptation(s) can include posterior flange 5 ; anterior flange 6 ; articular/condylar surface 10 which generally includes inferior, medial condyle 11 ; inferior, lateral condyle 12 ; posterior, medial condyle 13 ; posterior, lateral condyle (not illustrated in present drawings); anterior, medial condyle 15 ; anterior, lateral condyle (not illustrated in present drawings); and so forth. On the superficial side of the anterior flange 6 can be provided trochlear surface 17 , i.e., the trochlea, on which the actual or an artificial patella, i.e., the knee cap (not depicted), may generally ride. The femoral component for the knee generally is useful for surgical attachment to femoral bone stock 19 . A set of condyle-backing femoral spikes 7 and/or porous coating 9 such as of pore-coated metal may be provided.

The basic tibial component in addition to the addable component adaptation(s) can include articulating surface providing substance (tibial tray liner) 20 such as of ultra high molecular weight polyethylene (UHMWPE); articulating/condylar mating surfaces 21 (medial) and 22 (lateral); tibial tray 23 ; tibial tray liner stop/clip 24 ; rotation device/axial pin receiving receptacle or hole 25 . Metal-on-metal articulation may be provided by making the tibial component and its articulating surface 21 entirely of metal. Optionally, the basic tibial component may also contain the tibial spike receiving hole 27 C ( FIGS. 8 & 9 ) or 27 H (FIG. 16 ); supporting flanges 28 and/or pore coating 29 (FIG. 16 ). As well, the basic tibial component may contain a set of hole(s) through the tibial tray 23 through which bone screw(s) may be passed (not illustrated).

As previously alluded to, the preferable type of addable component 30 can be a spike 33 / 37 ( FIG. 14 ) or a posterior restraining member containing module such as the box ( FIG. 15 ) having rear posterior restraining bar 35 included therewith. A combination spiked and posterior restraining containing module may be made and employed, or a combination spiked and rotating member containing module may be made employed. Generally, the presence of a posterior restraint obviates the effective use of the rotating member.

Further, the addable component 30 of an inferiorly insertable rotation device with a swingable, depending male type part 50 , in general, can include housing 31 having side walls 32 ; top wall 33 ( FIGS. 1-3 , 6 & 7 ), which may be eliminated in certain embodiments (FIGS. 10 - 12 ); and front wall 34 . Thus, the top 33 of a modular box is optional. In fact, a preferred embodiment ( FIGS. 10-12 ) is topless. However, a top may impart structural stability, if required, and/or provide for another location to secure another component (e.g., FIG. 14 , femoral intramedullary spike) or provide a site for fastening of the box to its corresponding receptacle. Holes 52 in the side walls 32 accommodates hinge pin (axle) 55 . Pivot block (rotation member) 51 has hole 52 A, which continues along the direction of the holes 52 ; taper pin cup 53 ; and punch pin hole 54 . The axle 55 passes through the holes 52 & 52 A, providing a pivot for the rotation member 51 . The taper pin cup 53 may be smooth walled, tapered, say, with a Morse taper (FIGS. 3 & 7 ), or be provided with threads 56 ( FIGS. 1 , 2 & 6 ). Taper pin 61 is inserted into the cup 53 , and may be secured in place with punch pin 65 ( FIGS. 3 & 7 ) or with threads 66 ( FIGS. 1 , 2 & 6 ). Preferably, however, the part 50 is of one-piece construction 70 with block like upper rotation member portion 71 being made from the same piece as middle leg portion 73 and lower restraining post portion 70 , the latter two being in general cylindrical, with the restraining post closely conforming in shape to the receptacle 25 of the tibial component. Axle hole 72 may be provided in the upper portion 71 to accommodate passage of the axle 55 . Alternatively, the rotation member portion may be made integrally of one-piece construction with a built-in axle member appearing as opposing posts on either side of the member 71 , and the same fit into a housing 31 by bending the housing around to fit. Also, the housing 31 may include shaped front panels 34 L (lower) and 34 U (upper). The hole 34 H may be employed to secure the unit 50 into the femoral component through a screw or pin (passed into the hole 4 H). To provide for the restraining taper, for example, the aforementioned Browne & Sharpe taper, the sides 32 are tapered appropriately, say, at about a 1.6- to 2.1-degree angle 32 X (FIG. 11 ). The basic operational principles of an installed rotating member module parallel those of the artificial joint of the said patent to Goodman et al.

Module-in-module capability may be provided. For instance, the present invention can accommodate box-in-box capability. For example, the spike module 30 / 37 ( FIG. 14 ) may be made to be able to receive a further module such as a posterior stabilizing member module such as the module 35 / 50 or receive an inferiorly insertable rotation device with a swingable, depending male type part such as the module 30 / 50 or 30 / 70 .

Alternatively, a previously installed module may be removed before installing another module. In this connection, a pry slot (not illustrated) may be provided to the addable component module to assist in its removal.

Other adaptations for other insertable modular components can be provided for such as, for example, a separate posterior stabilizing rod 35 , which may be inserted into the hole 3 P (FIG. 13 ); a superiorly positionable femoral intramedullary spike 37 into the hole 3 H, which spike has internal threads 38 so that it may be secured with screw 39 ; or an inferiorly positionable tibial spike 27 Q, which spike has external threads for screwing into capped hole 27 C (FIGS. 8 & 9 ). However, these other adaptations and insertable modular components may not be so readily insertable after the basic joint has been implanted.

The addable component(s) may be added as may be indicated for a particular patient.

Further exemplary dimensions can include those which follow:

Feature Identity Dimension A9a (FIG. 9) 90-degree angle. A9b (FIG. 9) 118-degree angle. D10a (FIG. 10) 0.9602-inch distance. D10b (FIG. 10) 1.7073-inch distance. D10c (FIG. 10) 1.4375-inch distance. R10 (FIG. 10) 0.1500-inch radius. D12a (FIG. 12) 1.0703-inch distance. D12b (FIG. 12) 0.8509-inch distance. R12 (FIG. 12) 0.1875-inch radius. Suitable materials and methods can be employed to make the modular joint of the present invention, and the basic joint can be fashioned according to an anatomical foundation. See, e.g., the specification of the patent to Goodman et al. Thus, metals, ceramics, and plastics, to include engineering plastics, may be employed in the practice of the present invention. Preferably, however, metal is substantially used throughout, except, for example, for a tibial tray liner, again say, which may be of the UHMWPE, or for closures, and again say, which may be made of a suitable polyethylene material. More preferably, in total joint arthroplasties, the same metal is used for both joint components, for example, femoral and tibial components of the knee. Cobalt is a preferred metal or alloy base, especially when provided according to the well known ASTM F-799 or ASTM F-1537 standards.

Beneficially, the modular joint of the present invention is constructed along a basic joint foundation which can provide for natural load transfer. See, e.g., present FIGS. 1-16 . See also, the specification of the patent to Goodman et al.

Accordingly, among other embodiments in the practice of the present invention, the following is noted: in an artificial joint, which generally has natural load transfer capability, which includes a first component including a first articular surface and a rotation device, wherein the rotation device includes a swingable, depending male-type part; and a second component including a second articular surface for mating with the first articular surface, and a rotation device receptacle, wherein the rotation device receptacle includes a female-type part with the first component matable to the second component through male-female cooperation of the rotation device and the rotation device receptacle, and wherein the first component can cooperate with the second component in contact of the first and second articular surfaces and in articulation of the joint when the first component is mated to the second component, wherein the first and second articular surfaces are such that they can have anatomical gliding contact against one another during anatomical rotation in addition to anatomical flexion and extension the improvement can include an adaptation such that at least one addable component can be added to the basic joint without removal of the joint from a site to which it can be initially implanted. Also noted along the foregoing lines is the following embodiment of the present invention: in an artificial femoral component for a knee, which includes the following:

a femoral component frame, which includes two side walls connected to a front wall, the same being connectable in proximal and deep directions to distal condylar, posterior and anterior flanges, with the distal flange connected to the posterior and anterior flanges;

a smooth condylar surface of generally convex geometry connected to the femoral component frame in distal and superficial directions, which includes an inferior, medial condyle; an inferior, lateral condyle; a posterior, medial condyle; a posterior, lateral condyle; an anterior, medial condyle; and an anterior, lateral condyle; plus a trochlear surface on a superficial side of the anterior flange, on which a trochlea may generally ride; the condylar surface being such that an inter-condylar notch is present between medial and lateral condyles; and

a rotation device connected to the femoral component frame,

which includes the following:

an angular rotation member having a rotation member hole in a proximal extremity thereto, which hole spans the rotation member in a medial to lateral direction, which rotation member about a distal extremity thereof can be inserted into a corresponding receptacle in a tibial tray; and

an axle passing through the hole which spans the rotation member and is connected to a frame through holes in side walls thereof;

the improvement can include as the rotation device a modular, inferiorly insertable rotation device, which can be inserted into and removed from a corresponding receptacle in the femoral component frame, wherein the angular rotation member is connected to the axle which is connected to walls of the modular, inferiorly insertable rotation device by holes in the walls through which the axle passes.

CONCLUSION

The present invention is thus provided. Various features, parts, subcombinations and combinations may be employed with or without reference to other features, parts, subcombinations or combinations in the practice of the invention, and numerous adaptations and modifications can be effected within its spirit, the literal claim scope of which is particularly pointed out as follows.