US20120016485A1

US20120016485A1 - Implant components and methods

Info

Publication number: US20120016485A1
Application number: US13/156,246
Authority: US
Inventors: Jeffrey A. Sharp
Original assignee: Smith and Nephew Inc
Current assignee: Smith and Nephew Inc
Priority date: 2010-06-08
Filing date: 2011-06-08
Publication date: 2012-01-19
Also published as: WO2011156508A2; CA2802101A1; RU2012157130A; WO2011156506A3; WO2011156504A2; WO2011156511A2; AU2018200989A1; AU2011264848A1; CA2801739A1; WO2011156511A3; WO2011156504A3; EP2579816A2; WO2011156509A3; EP2579817B1; BR112012031296A2; WO2011156512A2; EP2579816A4; EP2579817A2; US20150150686A1; US10568741B2

Abstract

Systems, devices, and methods are provided for orthopedic implants. The implants may include a base member, such as an acetabular shell or an augment, that is configured to couple with an augment, flange cup, mounting member, or any other suitable orthopedic attachment. An implant component may be expandable to allow for adjustment and custom fitting during implantation. An expandable implant may have a first portion and a second portion separated by a slit. An expansion member can be disposed between the first and second portions and can be actuated to displace the two portions relative to each other, increasing the size of the implant. Any number of slits and expandable sections can be included in the implant to provided more flexibility in the expansion of the implant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S Provisional Patent Application No. 61/352,705, filed Jun. 8, 2010, U.S. Provisional Application No. 61/352,722, filed Jun. 8, 2010, U.S. Provisional Application No. 61/422,903, filed Dec. 14, 2010, and U.S. Provisional Application No. 61/466,817, filed Mar. 23, 2011, which are hereby incorporated by reference herein in their entireties.

BACKGROUND

Joints often undergo degenerative changes due to a variety of reasons. When joint degeneration becomes advanced or irreversible, it may become necessary to replace the natural joint with a prosthetic joint. Artificial implants, including hip joints, shoulder joints, and knee joints are widely used in orthopedic surgery. Specifically, hip joint prostheses are common. The human hip joint acts mechanically as a ball and socket joint, wherein the ball-shaped head of the femur is positioned within the socket-shaped acetabulum of the pelvis. Various degenerative diseases and injuries may require replacement of all or a portion of a hip using synthetic materials, typically metals, ceramics, or plastics.
More particularly, natural hips often undergo degenerative changes, requiring replacement of the hip joint with a prosthetic joint. Often, the hip is replaced with two bearing surfaces between the femoral head and the acetabulum. The first bearing surface is typically a prosthesis shell or acetabular cup, which may be formed of metal, ceramic material, or as otherwise desired. A liner (conventionally formed of polyethylene material such as ultra high molecular weight polyethylene, a ceramic material, or in some cases, even a metal liner) is then fit tightly within the shell to provide an inner bearing surface that receives and cooperates with an artificial femoral head in an articulating relationship to track and accommodate the relative movement between the femur and the acetabulum.
The cup (or a cup and liner assembly) is typically fixed either by placing screws through apertures in the cup or by securing the cup with cement. In some cases, only a liner is cemented in a patient due to poor bone stock. In other cases, a cup having a porous surface may be press fit into the reamed acetabular surface.
It may become necessary to conduct a second or subsequent surgery in order to replace a prosthetic joint with a (often larger) replacement joint. Such surgeries often become necessary due to further degeneration of bone or advancement of a degenerative disease, requiring removal of further bone and replacement of the removed, diseased bone with a larger or enhanced prosthetic joint, often referred to as a revision prosthesis. For example, bone is often lost around the rim of the acetabulum, and this may provide less rim coverage to securely place a press-fit cup. Such surgeries may thus be referred to as revision surgeries.
In acetabular revision surgery, an acetabular prosthesis generally includes additional mounting elements, such as augments, flanges, hooks, plates, or any other attachment or mounting points or members that provide additional support and/or stability for the replacement prosthesis once positioned. These additional mounting or attachment members are often required due to bone degeneration, bone loss, or bone defects in the affected area (in this instance, the hip joint).
Various types of these mounting members (which term is intended to include but not be limited to flanges, blades, plates and/or hooks) may be provided in conjunction with a prosthesis system in order to help the surgeon achieve optimal fixation, non-limiting examples of which include iliac flanges (providing securement and fixation in and against the ilium region of the pelvis), ischial blades (providing securement and fixation in and against the ischium), and obturator hooks (providing securement and inferior fixation by engaging the obturator foramen). Although there have been attempts to provide such mounting attachments with modularity, the solutions to date have generally fallen short of providing true modularity. Instead, they typically provide a few discrete positions at which the mounting members may be positioned, without providing the surgeon a fuller range of decision options.
Additionally, in some primary surgeries and more often in revision surgeries, the acetabulum may have a bone defect or void that the surgeon must fill with bone grafts before inserting a new shell. This can be time consuming and expensive, and may subject the patient to additional health risks. Some techniques use an augment in connection with the acetabular shell, which can be coupled to or otherwise attached to the outer surface of the shell.
With current augments, the surgeon can attach the augment to the bone and then implant the cup. However, many acetabular shells rely on bone screws to achieve proper fixation and the augment often gets in the way of a screw. In short, surgeons need the freedom to place screws in the best location, but this compromises their ability to use augments. With current systems, it also takes an increased amount of time surgical time to trial the component orientation and then try to find good bone fixation for the cup. The surgeon will often have to free-hand the amount of bone removed while estimating the size of augment needed. In the cases where bone is often deficient, surgeons are hesitant to take away any more bone than necessary.
Various additional features and improved features intended for use and application with various types of joint implants are also described herein, such as improved bone screws, improved coatings, and various augment removal and insertion options.

SUMMARY

Disclosed herein are systems, devices, and methods for providing modular orthopedic implants. The implants may include a base member, such as an acetabular shell or an augment, that is configured to couple with an augment, flange cup, mounting member, any other suitable orthopedic attachment, or any combinations thereof. Mounting members include, for example, flanges, blades, hooks, and plates. In some embodiments, the orthopedic attachments may be adjustably positionable about the base member or other attachments thereby providing modularity for assembling and implanting the device. Various securing and/or locking mechanisms may be used between the components of the implant. In certain embodiments, the orthopedic attachments are removably coupled to the base member or other components. In certain embodiments, the orthopedic attachments are integrally provided on the base member or other components, yet may still be adjustably positionable thereabout. In some embodiments, expandable augments, base members, or other bone filling devices are provided. In some embodiments, surface features are provided that create friction and allow for surrounding bone ingrowth at the interface of the implants and a patient's bone.
Systems, devices, and methods described herein provide implants that can be expanded or adjusted to fill bone voids in a patient's anatomy surrounding the implant. In certain embodiments, an orthopedic implant includes an acetabular implant with first and second portions that are separated along a side of the implant by a slit and an expansion member disposed between the first and second portions and adjustable by a tightening tool to displace the two portions relative to each other. The implant may also include a hinge that joins the first and second portions along a side of the implant. The first and second portions of an implant may comprise a solid portion, and the volume of the implant not including the solid portion may be porous. Any number of portions may be provided in the implant, and the implant may have any number of intersecting perpendicular slits for dividing the portions. The implant may be a flange connected to an acetabular shell, or may be an acetabular shell or cage. The implant may include a screw that passes through the implant to connect the implant to a patient's acetabulum.
In certain embodiments, an expansion member used in an expandable or adjustable implant may be a shaped memory plug or a screw. The expansion member may be an augment with a curved side and a connection site that attaches to an acetabular shell.
In certain embodiments, an orthopedic device is implanted in a patient's joint by installing an acetabular shell or cage within the joint and placing an augment between the shell and the patient's bone. Two portions of the augment are expanded until a first portion abuts the patient's bone and a second bone abuts the acetabular shell or cage, and the augment is anchored to the bone. The portions of the augment may be expanded using a tightening tool coupled to an expansion member disposed between the portions of the augment to displace the portions relative to each other. The expansion member used may be a shaped memory plug, a screw, or a wedge, and the tightening tool may include a torque-limiting device. The two portions of the augment may be expanded along a hinge that joins the portions. The portions of the augment may be biased towards one another. A screw may be passed through the shell to connect the shell to the patient's acetabulum. A porous surface may be applied to a portion of the augment. The augment may be removed via slits or flexible hinge portions provided on the augment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects and advantages will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:

FIGS. 1-5 show illustrative expandable/adjustable augments;

FIG. 6 shows an illustrative expansion member;

FIGS. 7-11 show illustrative expandable/adjustable augments;

FIG. 12 shows an illustrative expandable/adjustable augment with multiple expansion screws;

FIG. 13 shows an illustrative expandable/adjustable implant shell; and

FIG. 14 shown an illustrative augment having recess portions alongside a split portion.

DETAILED DESCRIPTION

To provide an overall understanding of the systems, devices, and methods described herein, certain illustrative embodiments will be described. Although the embodiments and features described herein are specifically described for use in connection with acetabular systems, it will be understood that all the components, connection mechanisms, adjustable systems, fixation methods, manufacturing methods, coatings, and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to medical devices and implants to be used in other surgical procedures, including, but not limited to: spine arthroplasty, cranio-maxillofacial surgical procedures, knee arthroplasty, shoulder arthroplasty, as well as foot, ankle, hand, and other extremity procedures.
Various implants and other devices described herein in their various embodiments may be used in conjunction with any appropriate reinforcement material, non-limiting examples of which include bone cement, appropriate polymers, resorbable polyurethane, and/or any materials provided by PolyNovo Biomaterials Limited, or any suitable combinations thereof Further non-limiting examples of potential materials that may be used are described in the following references: U.S. Patent Application Publication No. 2006/0051394, entitled “Biodegradable Polyurethane and Polyurethane Ureas,” U.S. Patent Application Publication No. 2005/0197422, entitled “Biocompatible Polymer Compositions for Dual or Multi Staged Curing,” U.S. Patent Application Publication No. 2005/0238683, entitled “Biodegradable Polyurethane/Urea Compositions,” U.S. Patent Application Publication No. 2007/0225387, entitled “Polymer Compositions for Dual or Multi Staged Curing,” U.S. Patent Application Publication No. 2009/0324675, entitled “Biocompatible Polymer Compositions,” U.S. Patent Application Publication No. 2009/0175921, entitled “Chain Extenders,” and U.S. Patent Application Publication No. 2009/0099600, entitled “High Modulus Polyurethane and Polyurethane/Urea Compositions.” Each of the prior references is incorporated by reference herein in its entirety.
Referring now to FIGS. 1-13, there are some instances during hip arthroplasty when an expandable augment or expandable shell implant may be desired. Initial fixation during hip arthroplasty is important, but the shapes of conventional augments may not be ideal and conventional bone preparation for receiving shaped augments and shells may not be precise. For example, hand-reaming is typically used to prepare an affected area of bone and create a shaped void for receiving an augment or shell. Although surgeons try not to remove more bone than necessary, in some instances, the surgeon may unintentionally create a slightly larger opening or an oblong void that does not precisely fit the shape of outer surfaces of an augment or shell to be implanted. Moreover, poor bone quality may affect the press fit and/or total interference between bone and an augment or shell even if the bone is well-shaped to fit external geometries of the augment or shell. Cement, allograft, and bone pastes have been used in the past to fill in the gaps between augments, bone, and implants. However, FIGS. 1-13 show several embodiments of augments, shells, and/or mounting members that may be expanded to compensate for poor bone quality or non-precise bone preparation (e.g., over-reaming). The augments, shells, and/or mounting members are preferably manufactured by a rapid manufacturing method (e.g., stereolithography, 3D-printing, selective laser sintering (SLS), electron beam welding (EBM), etc.). The augments, shells, and/or mounting members may also be machined or casted from a bulk material and then plasma-sprayed or otherwise coated with a surface texture or porous ingrowth structure. They may have a generally porous outside for contact with bone, and may have one or more non-porous external or internal surfaces and volumes for attaching to implants or improving strength and flexibility of the augments, shells, and/or mounting members.
The expandable augments, mounting members, or other implants, including shells and cages, have at least first and second portions that are connected, for example, by a soft or adjustable hinge portion or by a wire fixation or other suitable means, and the connections allow for separation of the portions. The separation is controlled by actuating an expansion member disposed between the at least two portions. As shown in FIGS. 1-5, an expansion member 1602, non-limiting examples of which may include a wedge, fastener, mandrel, screw, or other component, is inserted into an augment in order to expand the augment once it is placed inside or adjacent to a prepared bone cavity. The expansion member 1602 is actuatable, for example, by a surgical tightening rod or driver. A torque wrench can be utilized to ensure that the augment, shell, or mounting member has a proper interference or “press-fit” with surrounding bone, without fracturing the bone. Alternatively, as shown in the expansion member 1630 in FIG. 6, an expansion member itself may comprise torque-limiting means such as a frangible driver portion 1632 with a calibrated circumferential notch or groove 1634 that is designed to shear off after a specified torque is reached. By controlling the amount of torque applied to an expansion member, a proper press fit and interference with surrounding bone is achieved.
As shown in augments 1600, 1610, and 1620 in FIGS. 1-5, the outer geometries, shape, or size of an augment may be initially biased inwardly or undersized, and then expanded with an expansion member, which may alternatively comprise or be provided by a shape memory polymer or wedging action from a setscrew. For example, two portions 1604 and 1606 of augment 1600 in FIG. 1 are initially biased toward each other but are displaced away from each other upon actuation of the expansion member 1602. An augment, shell, or mounting member may have one or more flexible hinge portions, such as hinge area 1608 of augment 1600 to create a fulcrum for two or more other augment, shell, or mounting member portions to move in relation with each other. The geometries or portions of the augment, shell, or mounting member may also or alternatively be connected by a wire, screw, staple, threaded expansion rod or other structure, which holds the portions together but still allows them to expand under actuation of the expansion member. Additionally or alternatively, the augment or mounting member may have one or more slit portions, such as slit 1609 of augment 1600, to allow for even radial expansion. In certain embodiments, there may be a slit portion, a cruciform, or any other appropriately shaped cut or division in the augment, shell, or mounting member positioned a set desired distance or a set angle from one another so that the augment, shell, or mounting member portions expand evenly when one or more expansion members are positioned.
In FIGS. 2 and 3, an augment is provided that has two augment portions 1612 and 1614 separated by a slit 1616 and hinged together by a flexible hinge portion 1618. It will be understood that additional or fewer augment portions may be provided, and that the portions may also be provided on one or more mounting members and that the following description would be related thereto. The flexible hinge portion 1618 allows the augment portions 1612 and 1614 to move away from each other upon insertion of an expansion member 1602, which is shown as an expansion screw, but may be any other type of expansion member, such as a wedge, a plug, a bone screw, a set screw, a member having a smooth bore with a taper, a shape memory plug, or any other component, which, in turn, expands the entire augment. While not shown, one or more additional slits and/or flexible hinge portions may be added to allow a more uniform radial expansion.
The augment 1610 shown in FIGS. 2 and 3 may include one or more porous portions to facilitate bone ingrowth into the augment. For example, each of augment portions 1612 and 1614 may be porous. All of augment 1610 may be porous for bone ingrowth, or some portions of augment 1610 may be porous and some may be solid to provide strength to augment 1610. It may be desirable to provide a solid core in augment 1610 surrounded by porous outer portions to provide needed strength at the interface between augment 1610 and expansion member 1602 while still providing porous portions 1612 and 1614 for bone in growth. For example, the inner core of augment 1610 outlined by the dotted line in FIGS. 2 and 3 may be solid to provide needed strength around expansion member 1602 while augment portions 1612 and 1614 may be porous for ingrowth.
FIGS. 4 and 5 show an expandable augment 1620 that may be implanted and expanded similar to augments 1600 and 1610 discussed above in FIGS. 1-3. In particular, Augment 1620 includes two portions 1622 and 1624 that move radially outward when expansion member 1602 is inserted into augment 1620. Augment 1620 may be made of a solid material with surface treatment, a porous material, or may be a combination of solid and porous sections to provide both strength and bone ingrowth for the augment. The dotted line in FIGS. 4 and 5 may separate a solid core of augment 1620 that surrounds the threaded hole for expansion member 1602 from a porous peripheral portion of the augment, as discussed above with respect to FIGS. 2 and 3. The solid and porous portions may be located and separated within the augment in any suitable geometry, as shown in the different solid and porous geometries in augment 1610 of FIGS. 2 and 3 and augment 1620 of FIGS. 4 and 5.
During replacement or revision surgery, a surgeon may use any of the augments shown in FIGS. 1-5 to fill bone voids surrounding an implant. Depending on the anatomy of a certain patient and the surgical procedure, the augment may be placed into a bone void either before or after an implant shell is inserted. The augment may also be attached to the shell before implantation, before expansion begins, or after the augment is expanded to its final size. The surgeon positions the augment within the bone void in a contracted state such that there is space in the bone void that is not initially filled by the augment. The surgeon then activates an expanding component of the augment, for example, by turning a set screw with a surgical tool, to cause two or more portions of the augment to expand. The surgeon expands the augment until the augment fills substantially the entire bone void and abuts both the implanted shell and the patient's bone. The augment is then fixed in place, either by mechanical fasteners such as screws or by allowing surrounding bone to grow into ingrowth surfaces on the augment.
Because the augments, shells or mounting members shown and disclosed in FIGS. 1-13 are slowly expanded in-situ within the prepared bone void, impaction forces are avoided, but bone interference and press-fit is still achieved. Moreover, the risks of bone fracture, sitting too proud from a bone surface, and too much bone interference/press-fit (all generally being associated with impaction techniques) are mitigated or eliminated. It should be noted that one advantage of the devices shown in FIGS. 1-13 is that augments, shells, or mounting members may be more easily removed during revision surgeries due to the slits and flexible hinge portions provided thereon.
For example, in a revision hip surgery, a surgeon may first remove the expansion member and then simply impact the augment, shell, or mounting member radially-inwardly from a side portion to fold the augment or mounting member, urging the augment or mounting member portions towards each other and away from outer areas of bone ingrowth. In another example, the one or more slits generally “compartmentalize” the augment, shell, or mounting member into several smaller outer ingrowth surface areas. Therefore, each augment, shell, or mounting member portion may be removed individually from well-fixed bone with greater ease than for a well-fixed non-adjustable/expandable implant that may have an entire outer solid surface that is well-fixed with bone ingrowth. Lastly, slits may facilitate the entry of a saw blade, osteotome, or other cutting tool (e.g., a Midas Rex® pneumatic tool by Medtronic) for removing the augment, shell, or mounting member from well-fixed bone. The threaded openings provided in the augment, shell, or mounting member may be engaged by a threaded distal end of a slap hammer tool for removal from well-fixed bone in a manner similar to that used for hip stem removal during revision total hip arthroplasty (THA).
FIG. 7 shows an expandable/adjustable augment 1640 related to the embodiments described above and shown in FIGS. 1-6. The augment 1640 may have any outer peripheral shape to accommodate various bone voids and defects. While the entire augment 1640 may be solid and simply surface textured to improve bone ingrowth properties, volume portions of the expandable/adjustable augment 1640 may be fully porous. In FIG. 7, the augment 1640 comprises at least two fully- porous volume portions 1642 and 1644 separated by a solid portion 1646. The fully- porous volume portions 1642 and 1644 are movable with respect to each other. The solid portion 1646 may extend all the way to an outer periphery of the augment 1640 proximate a hinge region 1648 as shown in order to better distribute stresses and maintain the integrity of the struts and nodes of the ingrowth structures contained within the fully- porous volume portions 1642 and 1644. This design may help reduce cracks and fatigue failure. As shown in dotted lines in FIG. 7, the expandable/adjustable augments disclosed herein may comprise additional intersecting slits to separate portions of the augment into multiple portions, such as thirds, quarters, or any other appropriate division.
An expansion member 1650, which may be any of the above-described expansion members such as a screw, wedge, or plug, may be inserted into the augment 1640 to expand the augment 1640 in at least one direction, such as in a radial direction or a width. A receiving portion 1652 may be provided on the expandable/adjustable augment 1640 which receives the expansion member 1650, and is generally complementary to the shape of the expansion member 1650. For example while it may not be shown, either the expansion member 1650 or the receiving portion 1652 may be tapered, undersized, oversized, threaded, shim or wedge-shaped, threaded, smooth, symmetrical, non-symmetrical, conical, cylindrical, concentric, eccentric, and may be provided with various cross-sectional geometries, non-limiting examples of which are shown in FIGS. 8 and 9. In some non-limiting examples, the expansion member 1650 may comprise a screw, a quarter-turn fastener, a shape-memory plug, a wedge, or a settable or injectable material such as an injectable polyurethane, or packed graft material.
FIGS. 8 and 9 show non-limiting examples of a wedge expansion member for use with expandable/adjustable augments and mounting members disclosed herein. FIG. 8 shows a locking wedge 1690, and FIG. 9 shows a locking pin 1692 with a removal head 1694, which, when inserted into a recess of an expandable/adjustable augment or mounting member, may keep the augment or mounting member in a desired expanded state. The wedge expansion member shown in either FIG. 8 or 9 may be inserted at different depths within the expandable/adjustable augment to expand or contract the expandable/adjustable augment or flange to different diameters or peripheral shapes.
FIG. 10 shows an expandable/adjustable augment 1660 that is similar to the ones shown in FIGS. 1-7, incorporating a tapered plug expansion member 1662. The tapered plug expansion member 1662 may have an inclined or otherwise tapered outer surface that wedges against a complementary inclined or otherwise tapered inner surface provided within the body of the expandable/adjustable augment 1660.
FIG. 11 shows an expandable augment 1670 similar to the one shown in FIG. 10, wherein expansion of the augment 1670 is controlled by the turning of one or more positioning screws 1672. An upper plate member 1674 having an expansion member 1676 provided thereon is placed on top of an expandable augment portion. As the positioning screws 1672 are introduced and tightened, the upper plate member 1674 moves closer to the augment 1670, and the expansion member 1676 moves into a receiving portion 1678 located adjacent an expandable region in the augment 1670 to bulge the augment 1670 radially-outwardly.
FIG. 12 illustrates an expandable/adjustable augment 1680 similar to the ones shown in FIGS. 1-11, wherein expansion of the augment 1680 is controlled by the turning of multiple expansion screws 1682. The augment 1680 may be configured to expand by different amounts in different regions of the augment 1680. A plurality of slots 1684 may split the augment 1680 into several portions that are moveable relative to each other. The expandable/adjustable augment 1680 may be used to secure a press fit around its entire perimeter even if a surgeon wobbles a reamer, or if the bone void is prepared with a slightly different shape and/or size than the undeformed expandable/adjustable augment 1680.
FIG. 13 shows an expandable/adjustable implant shell 1700 that provides an implant having an adjustable size to allow for precise fit to a reamed bone void, similar to the expandable and adjustable augments discussed with respect to FIGS. 1-12. The shell 1700 has a threaded hole 1704 that receives an expansion member 1702. Expansion member 1702 may be a mandrel, screw, wedge, plug, or any other suitable expanding component. Depending on the expansion member used, threaded hole 1704 may be replaced by a non-threaded hole and may have any shape or contour needed to receive expansion member 1702 and cause the shell 1700 to expand. The shell 1700 has slits 1706 cut into shell 1700 to allow for flexibility needed to expand the shell. The slits 1706 create multiple segments 1708 around the shell that can be forced outward for expansion. Any number of slits 1706 and segments 1708 may be used to provide the desired amount of flexibility and expansion. As expansion member 1702 is placed into the shell 1700, for example, by a surgeon manually screwing expansion member 1702 into threaded hole 1704, the shell 1700 expands as segments 1708 are forced radially outwards, increasing the profile of the shell 1700 and allowing the shell 1700 to fill surrounding bone voids.
Expandable and adjustable augments may also be used to facilitate removal of the augments in revision surgeries. Implant shells occasionally require revision surgery due to wear of the implant or changes in a patient's anatomy, and revision surgeries to improve the implants may involve removing augments as well as implanted shells. An expanding augment that is used to fill a patient's bone void can make the removal process easier by allowing a surgeon to reverse the expansion and return the augment to its contracted state for quick removal. A modified expandable augment that provides for convenient removal is shown in FIG. 14.
FIG. 14 shows an augment 1240 that may be provided with recess portions 1242, which, in this embodiment, are shown alongside a split portion 1244, but which can be provided anywhere on the augment 1240, or even on augments not having a split portion. Recess portions 1242 are configured to receive a clamp or other instrument 1246. Recess portions 1242 may be curved or otherwise shaped to correspond to the instrument to be used. For removal of the augment 1240, arms 1248 of the instrument 1246 may be inserted into recess portions 1242 in order to securely grasp the augment 1240, squeeze the augment 1240, and pull the augment 1240 from bone. The mechanical advantage of the clamp 1246 causes the augment 1240 to squeeze or shut slightly or otherwise flex inwardly, particularly in split augment embodiments, so that the augment 1240 may be removed, even if well fixed in bone.
The split augment 1240 shown may move from a first position, shown as the outer boundary 1250 in solid lines, to a second compressed position, shown in dotted lines 1252 in a direction shown by inward arrows 1254. This compression allows removal of the augment 1240 in a relatively easier and more efficient manner than chipping away at the augment 1240 or cutting the augment 1240 out in separate portions with a blade.
Recess portions 1242 and instrument 1246 may also be used to initially position or introduce the augment 1240 into a bone void. Once positioned, an expansion member, such as any of the expansion members shown and described herein, may be used to expand and lock the augment 1240 into place. Although not shown, it may be desirable to insert plugs or any other appropriate recess portion cover to prevent bone ingrowth therein. Alternatively, bone graft material or injectable polymers or any other filler material may be inserted into recess portions, particularly if recess portions are to be used solely for insertion and are not envisioned for use in subsequent removal.
The foregoing is merely illustrative of the principles of the disclosure, and the systems, devices, and methods can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation. It is to be understood that the systems, devices, and methods disclosed herein, while shown for use in acetabular systems, may be applied to medical devices to be used in other surgical procedures including, but not limited to, spine arthroplasty, cranio-maxillofacial surgical procedures, knee arthroplasty, shoulder arthroplasty, as well as foot, ankle, hand, and extremities procedures.
Variations and modifications will occur to those of skill in the art after reviewing this disclosure. The disclosed features may be implemented, in any combination and subcombinations (including multiple dependent combinations and subcombinations), with one or more other features described herein. The various features described or illustrated above, including any components thereof, may be combined or integrated in other systems. Moreover, certain features may be omitted or not implemented.
Examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made part of this application.

Claims

1. An orthopedic implant comprising:

an acetabular implant having a first portion and a second portion, the first and second portions being separated along a first side of the implant by a slit; and

an expansion member disposed between the first and second portions, the expansion member being adjustable by a tightening tool to displace the two portions relative to each other.

2. The orthopedic implant of claim 1, further comprising a hinge that joins the first and second portions along a second side of the implant.

3. The orthopedic implant of claim 2, wherein the implant is a flange that is connected to an acetabular shell.

4. The orthopedic implant of claim 1, wherein the expansion member is a shaped memory plug or a screw.

5. The orthopedic implant of claim 4, wherein the implant is an augment with a curved side and a connection site that attaches to an acetabular shell.

6. The orthopedic implant of claim 1, wherein the implant is an acetabular shell or cage.

7. The orthopedic implant of claim 1, further comprising a screw that passes through the implant to connect the implant to the patient's acetabulum.

8. The orthopedic implant of claim 1, wherein the first and second portions, proximate the slit, comprise a solid portion.

9. The orthopedic implant of claim 8, wherein the volume of the acetabular implant not including the solid portion comprises a porous portion.

10. The orthopedic implant of claim 1, further comprising intersecting slits perpendicular to the slit for dividing the augment into a plurality of portions.

11. A method of implanting an orthopedic device in a patient's joint, comprising:

installing an acetabular shell or cage within the joint;

placing an augment between the shell and the patient's bone;

expanding two portions of the augment until a first portion abuts the patient's bone and a second portion abuts the acetabular shell or cage; and

anchoring the augment to the bone.

12. The method of claim 11, wherein the expanding comprises using a tightening tool coupled to an expansion member disposed between the two portions of the augment to displace the two portions relative to each other.

13. The method of claim 12, wherein the expansion member is a shaped memory plug or a screw.

14. The method of claim 12, wherein the expansion member is a wedge.

15. The method of claim 12, wherein the tightening tool includes a torque-limiting device.

16. The method of claim 11, further comprising expanding the two portions of the augment along a hinge that joins the first and second portions.

17. The method of claim 11, further comprising passing a screw through the shell to connect the shell to the patient's acetabulum.

18. The method of claim 11, further comprising applying a porous surface to a portion of the augment.

19. The method of claim 11, wherein the two portions of the augment are biased toward one another.

20. The method of claim 11, further comprising removing the augment via slits or flexible hinge portions provided thereon.