Patent Description:
A mount for an implant extractor assembly according to the invention is defined in claim <NUM> and an implant extractor assembly according to the invention is defined in claim <NUM>. In accordance with an exemplary embodiment, the subject disclosure provides a mount for an implant extractor assembly comprising a main body, a quick connect about a proximal end of the main body, and an L-shaped connector about a distal end of the main body. The L-shaped connector includes a through hole having a longitudinal axis transverse to a longitudinal axis of the main body.

According to the invention, the mount further comprises a mounting head configured for receiving a strike plate adjacent the quick connect. According to another aspect, the mounting head is between the quick connect and the L-shaped connector. According to another aspect, the mounting head is polygonal shaped. According to another aspect, longitudinal axis of the through hole is at an angle of about <NUM>° to <NUM>° from the longitudinal axis of the main body.

In accordance with another exemplary embodiment, the subject disclosure provides an implant extractor assembly comprising a handle, and the aforemeritioned mount connectable to the handle. According to an aspect, the through hole is positioned along the longitudinal axis of the main body. According to another aspect, the longitudinal axis of the through hole is at an angle of about <NUM>° to <NUM>° from the longitudinal axis of the main body.

According to the invention, the mount further comprises a strike plate configured to extend from the mounting head of the mount. According to another aspect, the strike plate extends substantially perpendicular to the longitudinal axis of the main body when assembled thereto.

According to an aspect, the main body includes a pair of opposing flats adjacent the quick connect for engaging the strike plate. According to another aspect, the main body includes a plateau for engaging the strike plate. According to another aspect, the mounting head is polygonal shaped.

According to an aspect, a longitudinal axis of the handle is parallel to a longitudinal axis of the main body when connected thereto. According to another aspect, a longitudinal axis of the handle is coaxial to a longitudinal axis of the main body when connected thereto.

According to an aspect, the handle includes a cooperating quick connect for operatively engaging the quick connect of the main body. According to another aspect, the implant extractor assembly further comprises a fastener for extending through the though hole. According to another aspect, the fastener comprises a stud and a nut. According to another aspect, the nut defines a distal shoulder preventing the nut from extending though the through hole.

The invention may be used in a method for removing an implant from a patient. The method comprises positioning the aforementioned mount over an implant having a shaft implanted within a patient. The method additionally comprises aligning the longitudinal axis of the mount to be substantially colinear with a longitudinal axis of the implant. The method further comprises inserting a fastener through the through hole of the mount and into the implant. The method also comprises applying a proximally directed force to the mount.

The following detailed description of exemplary embodiments of the subject disclosure will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, there is shown in the drawings exemplary embodiments. It should be understood, however, that the subject application is not limited to the precise arrangements and instrumentalities shown.

Reference will now be made in detail to the exemplary embodiments of the subject disclosure illustrated in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like features. It should be noted that the drawings are in simplified form and are not drawn to precise scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directiorial terms such as upper, lower, top, bottom, above, below and diagonal, are used with respect to the accompanying drawings. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the subject disclosure in any manner not explicitly set forth. Additionally, the term "a," as used in the specification, means "at least one. " The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.

"About" as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±<NUM>%, ±<NUM>%, ±<NUM>%, ±<NUM>%, or ±<NUM>% from the specified value, as such variations are appropriate.

"Substantially" as used herein shall mean considerable in extent, largely but not wholly that which is specified, or an appropriate variation therefrom as is acceptable within the field of art. "Exemplary" as used herein shall mean serving as an example.

Throughout the subject application, various aspects thereof can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the subject disclosure. For example, description of a range such as from <NUM> to <NUM> should be considered to have specifically disclosed subranges such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM> etc., as well as individual numbers within that range, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

Furthermore, the described features, advantages and characteristics of the exemplary embodiments of the subject disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the subject disclosure can be practiced without one or more of the specific features or advantages of a particular exemplary embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all exemplary embodiments of the present disclosure.

Referring now to the drawings, <FIG>, <FIG>and <FIG> depict an implant extractor assembly <NUM> according to an exemplary embodiment of present disclosure. The implant extractor assembly <NUM> includes a handle <NUM> and a mount <NUM> connectable to the handle. According to the invention, the implant extractor assembly further includes a strike plate <NUM> extendable from the mount <NUM> and may comprise a fastener <NUM> that can extend through a through hole <NUM> of a L-shaped connector <NUM> of the mount <NUM>. As will be explained below, the implant extractor assembly is adapted to engage an orthopedic implant.

The mount <NUM> is structured as shown in <FIG> and as set forth in greater detail below. The mount includes a quick connect <NUM> about a proximal end <NUM> of a main body <NUM> of the mount. In this illustrative embodiment, the quick connect <NUM> includes a relatively small circular cross-section about the top <NUM> of the quick connect. A flare <NUM> extends distally from the top <NUM> to a first post <NUM> of the quick connect. The first post <NUM> has an oval or racetrack cross-sectional shape similar in size and cross-sectional shape to a second post <NUM> that is co-axial to the first post <NUM>. An annular recess <NUM> is provided between the first post <NUM> and the second post <NUM> and has a significantly smaller diameter than the first and second posts. In this particular embodiment, the annular recess <NUM> has an oval or racetrack cross-sectional shape, though other configurations can be provided.

Proceeding in the distal direction from the proximal end, the second post <NUM> of the quick connect <NUM> is mounted or extends from a polygonal shaped block which serves as a mounting head <NUM> (also referred to as the block) for receiving or mounting the strike plate <NUM>. Although other configurations can be provided in accordance with the presently disclosed subject matter, such as the mounting head <NUM> being provided as regular hexagon or regular octagon, the polygonal shaped block in this particular embodiment has an irregular polygonal shape with <NUM>-sides and two flats <NUM>,<NUM> about opposite ends of the block. Given the length of the flats <NUM>,<NUM> the irregular polygon shape of block <NUM> in this embodiment can be described as generally having a rectangular shape, with four diagonal edges <NUM> cutting the four corners of the rectangle (<FIG>). Flat <NUM> defines a plane for face <NUM> of the main body, and flat <NUM> defines a plane for a second face <NUM> of the main body, which is opposite face <NUM>.

A plateau <NUM> extends from a mid-section <NUM> of the main body <NUM>. In this particular embodiment, the mid-section <NUM> defines a maximum width, W, of the mount <NUM> and has a rectangular cross-sectional shape. The polygonal shaped block <NUM> extends from the top surface of the mid-section defining the shape of the plateau <NUM>. The polygonal shaped block <NUM> has a maximum width less than a maximum width, W, defined by the mid-section <NUM>. The reduced maximum width of the block <NUM>, as compared to the width W of the mid-section <NUM> provides the plateau <NUM> upon which the strike plate <NUM> seats on or engages.

The shape and configuration of the block <NUM> and the plateau <NUM> are provided for purposes of illustration and not limitation. The strike plate <NUM> is adapted to provide a proper fitting (e.g., aperture) based on block <NUM> and plateau <NUM> of the main body <NUM>. The shape and configuration of the block and plateau can vary in other embodiments which include a strike plate.

A thickness, t, of the midsection <NUM> and the thickness of the mount <NUM> in general is provided by the distance between flats <NUM> and <NUM>. As noted, the mount <NUM> has a maximum width W at the mid-section <NUM>, and then tapers at taper <NUM> to provide a reduced distal width as one proceeds toward the L-shaped connector <NUM>, discussed in greater detail below.

In this particular illustrative embodiment, the main body <NUM> of the mount <NUM> continues to taper inward from taper <NUM> along a side <NUM> of the mount, at a constant thickness, t, until it reaches at or about the center of the width W defined by the mid-section <NUM>, as best shown in <FIG>. At this point, the main body <NUM> flares outward along the side <NUM> of the mount <NUM> to form a substantially upwardly or proximally facing face <NUM> of the L-shaped connector <NUM> that is angled relative to the longitudinal axis <NUM> of the mount. In accordance with exemplary aspects of the embodiment the angle α of the face <NUM> can be about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> degrees. An engorging face <NUM> to the L-shaped connector is oriented perpendicularly or substantially perpendicularly from the face <NUM>. In other words, the engorging face <NUM> faces downwardly about an angle β relative to the longitudinal axis <NUM> of the mount, e.g., about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> degrees. The side <NUM> of the mount opposite side <NUM> does not taper initially, but then tapers at taper <NUM> to run generally parallel to the face <NUM>, and is then angled perpendicularly or substantially perpendicular at a vertex <NUM> of the L-shaped connector to run parallel to the engorging face <NUM> thereby providing an L-shaped connector <NUM> having a through hole <NUM>.

As best shown in <FIG>, the longitudinal axis <NUM> of the main body <NUM> extends from the center of top <NUM> through the center of the quick connect <NUM>, and through the center of the mid-section <NUM>. A central axis <NUM> of the through hole <NUM> extends through the center of the through hole <NUM>, and traverses the longitudinal axis <NUM> of the main body <NUM>. In certain exemplary embodiments, the central axis <NUM> of the through hole is at an angle, y, of about <NUM>° to <NUM>° from the longitudinal axis <NUM> of the main body. In certain embodiments, angle γ can range from about <NUM>° to <NUM>°, from about <NUM>° to about <NUM>°, or can be about <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, or <NUM>° ± <NUM>° or ± <NUM>° or ± <NUM>°.

<FIG> depict a handle <NUM> that connects with the quick connect <NUM> about the proximal end <NUM> of the main body <NUM> via a cooperating quick connect <NUM> located about a distal end of the handle. Rendered transparent for purposes of clarity in <FIG>, a housing <NUM> surrounds the cooperating quick connect <NUM> of the handle <NUM>. The cooperating quick connect <NUM> includes an actuator <NUM> that is biased by a spring <NUM> or other biasing mechanism. The actuator contains a racetrack or oval actuator aperture <NUM>. A circular plane <NUM> is provided about the distal end of the handle, through which an oval or racetrack shaped aperture <NUM> in communication with a channel <NUM> having an oval or racetrack cross-sectional shape is provided. The aperture <NUM>, channel <NUM> and actuator aperture <NUM> each have a similar cross-sectional shape and are each sized and shaped to receive quick connect <NUM> of the main body <NUM>.

As best shown in <FIG>, in the normally biased position, the actuator aperture <NUM> is not aligned with the channel <NUM> such that the channel <NUM> of the cooperating quick connect <NUM> is partially obstructed by the spring-biased actuator <NUM>. As the quick connect <NUM> of the main body <NUM> is inserted into the cooperating quick connect <NUM> of the handle <NUM>, the flare <NUM> will advance the actuator aperture against the bias of spring <NUM> to force the actuator aperture in co-alignment with the channel <NUM> to accommodate the distally increasing diameter of the quick connect <NUM>. Once the actuator reaches the annular recess <NUM> of quick connect <NUM>, the actuator is allowed to return to its normally biased position, in which the channel <NUM> is again partially obstructed. The partially obstructed channel <NUM> does not allow movement of the mount <NUM> owing to the relatively larger diameters of the first post <NUM> and the second post <NUM> of the quick connect <NUM>, and the handle <NUM> is locked into place. To remove the handle, the actuator <NUM> is depressed to co-align the actuator aperture <NUM> with the channel <NUM> and allow the first post <NUM> to clear the actuator <NUM>.

A T-handle <NUM> is connected to the housing <NUM> defining the proximal end of the handle <NUM>. In this particular embodiment, the T-handle includes a shaft <NUM> centered about a gripper <NUM> ergonomically structured for gripping by a user's hand.

<FIG> depicts a handle <NUM> according to an alternative exemplary embodiment for connection with the mount <NUM>. The handle provides a gripper <NUM> that is sized and shaped to be ergonomically gripped by at least one hand. The handle <NUM> contains a cooperating quick connect <NUM> similar or identical in design to the cooperating quick connect <NUM> discussed above in <FIG>.

As shown in <FIG>, the handle <NUM> can in certain embodiments further include a second cooperating quick connect <NUM> about an end opposite the cooperating quick connect <NUM>, which has a second actuator and a similar design to cooperating quick connect <NUM>. Second cooperating quick connect <NUM> is distinguished from cooperating quick connect <NUM> in that it has a circular shaped aperture <NUM> about a proximal face, that forms an aperture to a channel with a circular cross-sectional shape (not shown).

<FIG> depicts a handle component <NUM> according to another exemplary embodiment that can be used, for example, in conjunction with the handle <NUM>. The handle component <NUM> includes a T-handle <NUM> similar to T-handle <NUM>, having a shaft <NUM>. The handle component <NUM> further includes a handle quick connect <NUM> similar to quick connect <NUM> of the main body <NUM>. Handle quick connect <NUM>, however, includes a first post <NUM>, a second post <NUM>, and an annular recess <NUM> each having a circular cross-sectional shape. Handle quick connect <NUM> can be engaged with the second cooperating quick connect <NUM> to join handle <NUM> with handle component <NUM>. A hub <NUM> with a relatively large diameter is provided centrally about, and between, the shaft <NUM> and the handle quick connect <NUM>. Other alternative configurations can be provided in accordance with the subject disclosure.

In accordance with an exemplary embodiment the strike plate <NUM> is structured as shown in <FIG>, which can be included in the implant extractor assembly <NUM> in certain embodiments. The strike plate includes an aperture <NUM> that has a regular octagonal shape that is sized such that it can be securely connected about the mounting head <NUM>, which in this embodiment is generally a rectangular shape, with four diagonal edges cutting the four corners of the rectangle. The shape of the polygonal shaped block <NUM> and the aperture can be modified, so long as the strike plate <NUM> is secured about the mounting head <NUM>. The strike plate <NUM> has a pair of opposite planar faces <NUM>, <NUM> having an increasing width about an end opposite the aperture <NUM> as shown in <FIG> to provide a surface for striking the strike plate with e.g., a surgical hammer (not shown).

<FIG> depicts the fastener <NUM> according to an exemplary embodiment. The fastener <NUM> includes a socket head <NUM> that has a diameter larger than the diameter of the through hole <NUM> of the L-shaped connector. A proximal end <NUM> to the socket head <NUM> can include a standard sized socket fitting. A shaft <NUM> proceeds from the socket head and has a diameter sized to fit or slide through the through hole <NUM>. The shaft <NUM> can be provided with threading <NUM> about its distal end <NUM>, and have an overall longitudinal length that can vary depending on the orthopedic implant which is being extracted. The diameter of the shaft, or, in embodiments that do not include a circular shaft, the size of the shaft in general, is based on the diameter or size of an existing anchor hole (e.g., hole <NUM>, <FIG>) in the orthopedic implant being extracted. For example, if the existing anchor hole does not contain threading, or if the existing anchor hole has a specific contour, the shaft can be provided without threading, or with a complementary contour, depending on the orthopedic implant being removed. In any event, the shaft <NUM> is sized to fit securely within the existing anchor hole <NUM> of the implant, and in this exemplary embodiment, the threading <NUM> is complementary to threading provided in the anchor hole.

<FIG> depict another exemplary embodiment of a fastener <NUM> suitable for use in the implant extractor assembly <NUM>. As shown in <FIG>, the fastener <NUM> is received in the through hole <NUM> of the L-shaped connector <NUM> of the mount <NUM>. Unlike the unitary fastener <NUM> described above, <FIG> show that the fastener <NUM> is preferably of two-part construction. More particularly, the fastener <NUM> is comprised of a stud <NUM> and a nut <NUM>, wherein the stud is threadedly connectable to the nut and to an implant to be extracted, as described below.

The stud <NUM> is best shown in <FIG> and <FIG>. As shown in those figures, the stud comprises proximal threading <NUM> and distal threading <NUM> separated by a smooth-walled central section <NUM>. It is understood that the stud <NUM> may alternatively be threaded throughout its entire length. As shown in <FIG>, the stud <NUM> extends through the through hole <NUM> whereby the distal threading <NUM> is configured to be threaded into the anchor hole <NUM> of implant <NUM> as described below in connection with <FIG>. The proximal threading <NUM> is configured to be threaded into a threaded hole <NUM> provided in a distal end <NUM> of the nut <NUM> as described below. A proximal end <NUM> of the stud <NUM> can be provided with a multisided socket <NUM>, e.g., a Torx head.

The nut <NUM> is best shown in <FIG> and <FIG>. As shown in those figures, the nut includes a tool engageable head <NUM> at proximal end <NUM> thereof. According to an aspect, the tool engageable head comprises a plurality of external faces <NUM> arranged in a polygon. According to a further aspect, <FIG> shows that the tool engageable head comprises a socket <NUM> having a plurality of internal faces <NUM> arranged in a polygon, e.g., a Torx head.

<FIG> shows that the nut <NUM> defines a distal shoulder <NUM> preventing the nut from extending through the through hole <NUM>. <FIG> shows that the tool engageable head <NUM> is offset a distance "O" from the shoulder <NUM>, whereby the tool engageable head can be readily engaged by a suitable tool such as a wrench, a nut driver, or a polygonal key, e.g. a hex key or a Torx tool.

The goal of the stud and nut fastener <NUM> is to rigidly connect to the implant and not have any inadvertent dampening when impact loading is applied during implant extraction. To achieve this end, the extraction instrument needs to be securely tightened to the implant. With the simple fastener <NUM> (<FIG>), the fastener would need to have a specific length to ensure proper thread engagement with the implant. However, implants can potentially vary between make and model. Therefore, to account for all possible variations there would need to be different lengths of fasteners <NUM> or spacer shims manually assembled to the fastener to work effectively. In contrast, the stud and nut fastener <NUM> is advantageous in that it automatically takes account of a range of implant socket depths, e.g., from about <NUM> to <NUM> (<NUM> inches).

When securing the fastener <NUM> to an implant such as implant <NUM> (<FIG>), the stud <NUM> is passed through the through hole <NUM> and the distal threading <NUM> is threaded into the anchor hole <NUM> of the implant. The stud is then is firmly tightened in the anchor hole by an appropriate tool received in the socket <NUM> at the proximal end <NUM> of the stud. Once the stud <NUM> is sufficiently tightened within the implant, the threaded hole <NUM> provided in a distal end <NUM> of the nut <NUM> is threaded onto the proximal threading <NUM> of the stud until the nut is fully threaded onto the stud of until the shoulder <NUM> of the nut contacts the L-shaped connector <NUM>. The nut is then tightened onto the stud by an appropriate tool engaging the tool engageable head <NUM>. With the stud tightened to the implant and the nut tightened to the stud, the mount <NUM> of the implant extractor assembly <NUM> is securely tightened to the implant. With the mount tightened to the implant, there is no play between the fastener <NUM> and the implant which could dampen the impact effect of a striking tool striking the underside of the strike plate <NUM> during implant extraction.

<FIG> depict an orthopedic implant <NUM> to which implant extractor assemblies of the present disclosure can be applied, such as in a revision surgery. The implant <NUM> can include a humeral stem <NUM> and a humeral head <NUM>. The humeral head <NUM> can be provided with one or more apertures, including the anchor hole <NUM>, to receive, for example, a humeral concavity insert for contact with the glenosphere. The center of the anchor hole <NUM> defines a longitudinal axis <NUM> of the implant. As depicted in <FIG>, the humeral stem <NUM> has been previously inserted into a humerus <NUM>, and the shoulder area <NUM> has been isolated for revision surgery, with the humeral concavity insert having been removed.

In operation, the mount <NUM> is positioned over the humeral head <NUM>. The central axis <NUM> of the through hole is aligned with a central axis <NUM> of the implant. So aligned also aligns the longitudinal axis <NUM> of the mount to be substantially parallel with the longitudinal axis <NUM> of the implant. The fastener <NUM> (or fastener <NUM>) is then inserted through the through hole <NUM> of the mount <NUM> and into the implant (e.g., into anchor hole <NUM>). In this position, the longitudinal axis of the mount <NUM> is offset but substantially parallel to a longitudinal axis <NUM> of the implant. A proximal force is then applied to the handle <NUM> to remove the implant <NUM>, possibly augmented by striking the underside of the strike plate <NUM> with a striking tool. As the longitudinal axis <NUM> is aligned with e.g. parallel with the longitudinal axis of the implant, the proximally directed force advantageously provides a line of force in a single direction that facilitates removal of the implant from bone.

Claim 1:
A mount (<NUM>) for an implant extractor assembly, the mount (<NUM>) comprising: a main body (<NUM>);
a first connector (<NUM>) about a proximal end (<NUM>) of the main body;
a second L-shaped connector (<NUM>) about a distal end of the main body, the second L-shaped connector including a through hole (<NUM>) having a longitudinal axis (<NUM>) transverse to a longitudinal axis (<NUM>) of the main body; and
a strike plate (<NUM>), characterised by a mounting head (<NUM>) configured for receiving the strike plate (<NUM>) adjacent the first connector (<NUM>), wherein the strike plate (<NUM>) is configured to extend from the mounting head (<NUM>) of the mount (<NUM>).