Patent Description:
Skeletal joints have a variety of configurations providing for a wide range of smooth movement of two or more bones relative to each other. For example, in a shoulder joint, the head of the humerus interacts with the glenoid cavity of the scapula in a manner similar to a "ball and socket" joint.

Over time, it may become necessary to replace a joint, such as the shoulder joint, with a prosthetic joint. The prosthetic joint can include components mounted to one, two or more than two bones at the joint. For example, the prosthetic joint can include a humeral component, a glenoid component or both a humeral and a glenoid component.

Conventional humeral components include a humeral head jointed to a stem. The stem is configured to be inserted into a medullary canal of the humerus. In certain cases, insertion of the stem disadvantageously requires bone to be removed to fit the stem to the medullary canal due to patient-to-patient anatomical variation.

Another disadvantage of this approach is that integration of the stem into the bone through a natural process of bone ingrowth can make it difficult to remove the humeral component if it becomes necessary to replace the humeral component with another device.

A stemless humeral component may be used to address some of the disadvantages of conventional humeral components. Stemless humeral components can decrease the amount of bone loss in preparing the humerus to receive the component and decrease the complexity of the joint replacement procedure.

Stemless humeral component designs can be more challenging to secure to the humerus. Typically the humeral head is resected creating an exposed face. The exposed face may include cancellous bone that can degrade in certain circumstance.

<CIT> describes a humeral head prosthetic device which includes a chassis and a head attached or attachable to the chassis. The chassis includes a tapered and multifaceted anchor element attached to and projecting distally from a base element, the configuration of the tapered and multifaceted anchor element being adapted to counter rotation of the chassis once it is impacted into the humeral head. One or more blind holes are defined in part by a penetrable wall, each of the blind holes including a wall that may be readily penetrated in order permit insertion of a tool to aid in removal of the prosthesis where such removal is required.

<CIT> describes a support element for humeral implant which comprises a central body extending along an axis and at least three arms extending outwardly from the central body, the arms being transversal to said axis and bearing a ring element at their ends opposite to said central body, wherein at least a first and a second pair of arms form different angles.

Accordingly, there is a need for additional stemless components or prostheses designed to reduce bone erosion or degradation due to stress shielding and in some cases to preserve bone in initial implantation while enhancing initial pull-out and back-out resistance. The reduction of bone erosion and the enhanced pull-out and back-out resistance can be augmented in patient specific embodiments. Preferably enhanced initial dislodgement resistance will also provide excellent long term fixation.

In some embodiments, there are provided a stemless humeral anchor and a kit according to the appended set of claims.

Any feature, structure, or step disclosed herein can be replaced with or combined with any other feature, structure, or step disclosed herein, or omitted.

These and other features, aspects and advantages are described below with reference to the drawings, which are intended to illustrate but not to limit the inventions. The invention is illustrated in Figures <NUM>-<NUM>. The devices shown in <FIG> do not form part of the invention. In the drawings, like reference characters denote corresponding features consistently throughout similar embodiments.

The following is a brief description of each of the drawings.

While the present description sets forth specific details of various embodiments, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting.

Furthermore, various applications of such embodiments and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described herein.

Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.

Section I (<FIG>) of this application discusses the problem of stress shielding in the context of a humeral implant.

In Section II (<FIG>), a kit that includes both anatomic and reverse shoulder implant assemblies for treating shoulder conditions that can be, patient specific at least in part, are discussed.

Section III (Figures <NUM>-<NUM>) is directed to a variety of press-fit anchors according to the invention that can be included in the kits discussed in Section II. Section IV (<FIG>) discusses a variety of multipart anchors, not forming part of the invention, that can provide advantageous bone retention even immediately following implantation.

Section V (<FIG>) is directed to various methods, not forming part of the invention, of implanting anchors disclosed herein. Section VI (<FIG>) discusses additional apparatuses, not forming part of the invention, and methods, also not forming part of the invention, that can be used for the glenoid and other bones. Section VII (<FIG>) discusses the retention performance of embodiments disclosed herein. Section VIII (<FIG>) discuss multi-part implants, not forming part of the invention, configured to reduce, minimize or eliminate stress shielding.

<FIG> illustrate a problem that can arise from excessive stress shielding following implanting of a stemless humeral assembly. As will be discussed in greater detail below, a humeral anchor <NUM> and an articular component <NUM> can be implanted in a proximal humerus H following the resection of the humeral head. The humeral anchor <NUM> may be a stemmed or stemless anchor. Figures <NUM>-<NUM> illustrate various press-fit stemless configurations and <FIG> illustrate various two part stemless anchors.

<FIG> show that the resection typically creates an exposed face F. If the humeral anchor <NUM> has a lateral outer periphery that is much smaller than the periphery of the humeral head at the exposed face F, at least a peripheral portion of the face F can continue to be exposed after the anchor <NUM> is placed. For example, <FIG> shows that an annulus of the exposed face F that continues to be exposed following implantation of the anchor <NUM>. The annulus is seen between the outer periphery of the anchor <NUM> and the outer periphery of the face F. <FIG> shows that the annulus can have a dimension EA at any rotational position about the anchor <NUM>. The stemless humeral assembly may be designed to be implanted so that the lateral side of the articular component <NUM> does not come into direct contact with or has minimal direct contact with the face F when the component <NUM> is secured to the anchor <NUM>. If the outer periphery of the articular component <NUM> is larger than that of the anchor <NUM> there can be an overhang where neither the anchor <NUM> nor the articular component <NUM> contacts the exposed face F. The overhang prevents any loads from being applied to the exposed face F in the annulus, e.g., over the dimension EA. It has been seen that when the dimension EA is too large the medial calcar region MC of the humerus can be subject to bone resorption which can compromise the integrity of the humerus following implantation of the stemless shoulder assembly.

<FIG> also shows the form of one head of the humerus H. As with other traits of individuals, the form of the head of the humerus H can vary for specific patients. That is, the transverse perimeter or surface area of planes parallel to the exposed face F in the direction of the arrow A may range from increasing to gradually decreasing and in some cases to rapidly decreasing in perimeter of surface area. Accordingly, the closeness in one or more of shape and radial, axial, lateral, anterior, posterior, distal, and circumferential extent of the portion of the anchor <NUM> below (e.g., lateral of) the exposed face F to the outside wall of the humeral head can vary by patient and if too small can compromise the integrity of the bone and/or the integrity of the fixation of the anchor <NUM> to the bone. If the portion of the anchor <NUM> below the exposed face F is spaced too far from the outside wall of the humeral head the opportunity for improved fixation in a patient with a larger humeral head is lost.

This application discusses new orthopedic assemblies that employ patient specific features to reduce stress shielding and to otherwise provide for better fit and retention of the assemblies in bone. Of particular interest is such an orthopedic assembly for use in shoulder arthroplasty, e.g., to humeral and glenoid assemblies.

<FIG> shows a kit <NUM> that includes a press-fit anchor <NUM> or any of the press-fit anchors 10A-10E or a shoulder assembly <NUM> including a base <NUM> or any of the bases 104A-104E. The kit can include a trunnion 954A (see <FIG> and <FIG>) or other component that can be configured to couple with one or more of the bases 104A-104Eand can be patient specific, for example having an outer periphery that reduces, minimizes or eliminate the exposed portion of the exposed face F disposed radially outward of the base. The trunnion 954A can reduce, minimize or eliminate the dimension EA (see <FIG>) in the vicinity of the medial calcar MC or any other bone portion subject to erosion from stress shielding or entirely around the outer periphery of the base to which the trunnion is coupled. The kit <NUM> can include one or both of an anatomic articular component <NUM> and a reverse articular component <NUM>. The anatomic articular component <NUM> can comprise a one-piece structure including a convex articular surface <NUM> disposed on a proximal or lateral side and a tapered projection <NUM> disposed on a distal side thereof. The reverse articular component <NUM> can comprise a two-piece structure including a tray <NUM> and an insert <NUM>. In other embodiments, the articular component <NUM> has a one-piece configuration. In other embodiments, the articular component <NUM> has a monolithic configuration. Monolithic embodiments can comprise a one material configuration. Monolithic embodiments can comprise two or more material. The insert <NUM> can mate with the tray <NUM> in any suitable manner, such as by interference fit or snap fit. The tray <NUM> can include a tapered projection <NUM>. <FIG> shows that the kit <NUM> also can include a glenoid sphere <NUM> and corresponding components for anchoring the glenoid sphere in a glenoid. The insert <NUM> is shown in just one embodiment in which the tray is angled, such that a plane intersecting the medial side of the insert <NUM> is at an angle to the side that faces the shoulder assembly <NUM> providing a thicker superior portion. In other embodiments the insert <NUM> is angled, such that a plane intersecting the medial side of the insert <NUM> is at an angle to the side that faces the shoulder assembly <NUM> providing a thicker inferior portion. In other embodiments the insert <NUM> is not angled, such that the plane intersecting the medial side of the insert <NUM> is substantially parallel to the side that faces the shoulder assembly <NUM>.

<FIG> and <FIG> shows the shoulder assembly <NUM> implanted in an exposed face F of a humerus H. Various embodiments of components of the assembly <NUM> are shown in exploded form and separately in <FIG>. The assembly <NUM> has a recess <NUM> in which further components of a prosthetic shoulder joint can be secured. The assembly <NUM> and the recess <NUM> enable the humerus H to be fitted with either an anatomical shoulder by receiving the anatomic articular component <NUM>, more particularly, the projection <NUM> or a reverse shoulder component <NUM> by receiving the projection <NUM> either initially or as part of a revision procedure. Methods of using the kit <NUM> to implant the shoulder assembly <NUM> as part of a shoulder prosthesis are discussed below in connection with <FIG>. <FIG> show that embodiments of the kit can be used in orthopedic applications other than in humeral and shoulder joint procedures. <FIG> illustrate various embodiments embodying multi-component humeral anchors some components that can be combined in a similar kit. Some of the components of various embodiments and kits can be adapted for a specific patient based upon pre-operative or intra-operative analysis of that patient's bone, e.g., CT scan, MRI, or X-ray imaging, including in some cases providing a separate flange member configured for a specific patient to extend outward an in certain applications cover the annular region of the exposed face F that in the prior art was left uncovered and subject to stress shielding. While incremental differences in these embodiments and methods are discussed below, it is to be understood that features of each embodiment can be combined with features of the other embodiments, as appropriate.

Figures <NUM>-<NUM> illustrate examples of shoulder assemblies that can employ a press-fit humeral anchor <NUM> according to the invention, wherein at least a portion of the anchor <NUM> is adapted for a specific patient based upon pre-operative or intra-operative analysis of that patient's bone, e.g., CT scan, MRI, or X-ray imaging.

<FIG> shows a stemless humeral anchor <NUM> that can be press-fit into the humerus H. As discussed in greater detail below at least a portion of the stemless humeral anchor <NUM> is adapted for a specific patient following imaging, e.g., pre-operative or intra-operative imaging. The stemless humeral anchor <NUM> includes a first end <NUM> and a second end <NUM>. The first end <NUM> is adapted to be embedded in the humerus H. The second end <NUM> is opposite the first end <NUM>. The second end <NUM> is adapted to be placed at the resection plane covering at least a portion of the face F. The stemless humeral anchor <NUM> also includes a mating portion <NUM>. The mating portion <NUM> includes a recess <NUM> configured to receive a corresponding mating portion of an articular component of a humeral assembly as discussed further below. The mating portion <NUM> can include a generally cylindrical form. In some embodiments a portion of the mating portion <NUM> spaced away from the second end <NUM> includes a tapered form.

The stemless humeral anchor <NUM> includes a collar <NUM> disposed at the second end <NUM>. The collar <NUM> extends around the mating portion <NUM>. The collar <NUM> extends transversely to and in some cases laterally of a longitudinal axis LA of the mating portion <NUM>. The collar <NUM> is configured to rest on the exposed face F following resection of the humerus H.

The stemless humeral anchor <NUM> includes a plurality of arms <NUM>. The arms <NUM> are examples of rotation control features that are provided on the anchor <NUM>. Other arms herein are also examples of rotation control features that can be provided on the anchor with which such arms are described. The arms <NUM> are examples of rotation control features that are fixed relative to the mating portion <NUM> of the anchor <NUM>. The arms <NUM> are examples of rotation control features that are fixed relative to the recess <NUM>. The arms <NUM> are examples of rotation control features that can extend radially away from a periphery of the anchor <NUM> be disposed below the resection of the humerus when implanted. The arms <NUM> are examples of rotation control features that can extend axially away from a distal surface of the anchor <NUM> to be disposed below the resection of the humerus when implanted. The arms <NUM> are examples of rotation control features that are unitary with the collar <NUM>, the mating portion, and the recess <NUM> such that, in use, such rotation control features are inserted simultaneously into the prepared humerus as discussed further below. The arms <NUM> project from the mating portion <NUM> in some embodiments. The arms <NUM> extend toward the first end <NUM> from the collar <NUM> in some embodiments. The arms <NUM> extend toward the second end <NUM> from the first end <NUM> in some embodiments. As noted above, at least a portion of the stemless humeral anchor <NUM> can be made for a specific patient following pre-operative imaging. <FIG> shows that the stemless humeral anchor <NUM> can include one or more arms 22A that has a different form or shape from one or more other arms <NUM>. Specifically the arm 22A the can be seen to have a larger radial extent. In more detail the arms 22A can extend further away from the longitudinal axis LA than the other two arms <NUM> of the stemless humeral anchor <NUM>. Also, the arms 22A can be seen to have any shape specific to pre-operative intraoperative or other imaging, including without limitation a generally straight side that extends from adjacent to the second end <NUM> of the stemless humeral anchor <NUM> toward the first end <NUM>. The arms 22A can have a tapered edge at an end of the straight side closest to the first end <NUM>. In contrast the other two arms <NUM> can be generally continuously curved from the second end <NUM> to the first end <NUM>. The arms 22A can be configured to be received in a resected humerus H where additional bone mass or volume of bone is located at the position at which the arms 22A would be disposed when the stemless humeral anchor <NUM> is implanted. Also, the arms 22A would be accommodated in a humerus H where the outside wall thereof extends generally distally toward the shaft of the humerus H without curving rapidly inwardly. The arms 22A have a larger surface area from the mating portion <NUM> to the straight edge thereof than is provided in the arms <NUM>. The arms 22A are thus able to provide greater surface area for bone ingrowth which provides a more secure connection with the cancellous bone of the humerus H. The arm or arms 22A being augmented, e.g., larger, or a different form or shape, having modified edges, provides an example of a structure configured to be disposed beneath the face F in the cancellous bone therebelow that can be enhanced for patient specific performance.

<FIG> shows another embodiment of a stemless humeral anchor 10A that also can be configured in a sub-surface portion in a patient specific manner. The stemless humeral anchor 10A is similar to the stemless humeral anchor <NUM> except as described differently. The stemless humeral anchor 10A includes a void filling protrusion <NUM> that can be formed in a patient specific manner, utilizing, for example, <NUM>-D printing technology. The void filling protrusion <NUM> can be formed with reference to pre-operative imaging such as CT scan, MRI scan, X-ray or other imaging. The void filling protrusion <NUM> can be used to fill a cancellous portion of bone located within the outer cortical bone layer of the humerus H. For example, prior to surgery a scan of the humerus H can be made using any suitable technology. In the scan a hollowed out area can be identified that is at distal of the resection plane forming the face F. Solidifying the cancellous bone can be confirmed as an appropriate medical objective. The three dimensional shape of the area to be solidified can be determined. That shape can be used to form the void filling protrusion <NUM> using any suitable technique. One approach is to use additive manufacturing, such as 3D printing or the like, to form the void filling protrusion <NUM> in a manner that fills the area to be solidified.

<FIG> shows that the void filling protrusion <NUM> is contiguous with one of the arms <NUM>. The void filing protrusion <NUM> is contiguous with rotation control features, e.g., one of the arms <NUM> and extend circumferentially therefrom, e.g., toward another one of the arms <NUM>. In other embodiments the void filling protrusion <NUM> can be spaced apart from the arms <NUM>. For example, the void filling protrusion <NUM> can be configured as a radial protrusion from the mating portion <NUM>. The void filling protrusion <NUM> can have a first end 24A and a second end 24B. The first end 24A can be located between the first end <NUM> and the second end <NUM>. The second end 24B will normally be located at or adjacent to the second end <NUM>. Extending the second end 24B to the second end <NUM> of the stemless humeral anchor 10A allows for some preparation of the void to be filled from the face F in a direction that is distal on the humerus H. Although <FIG> shows that there can be one void filling protrusion <NUM> on the stemless humeral anchor 10A, in other embodiments there can be more than one void filling protrusion <NUM>. Where there are more than one void filling protrusion <NUM> the shape and configuration of the void filling protrusions <NUM> will generally be different. The void filling protrusion <NUM> need not extend straight from the second end <NUM> toward the first end <NUM>. Instead, the void filling protrusion <NUM> can be curved to some extent between the second end 24B and the first end 24A. For example, the second end 24B can be spaced farther from the nearest arms <NUM> than is the first end 24A. The outermost radial extent of the void filling protrusion <NUM> between the second end 24B and the first end 24A can follow a curved contour.

The void filling protrusion <NUM> can be configured to allow for bone ingrowth into the void filling protrusion <NUM>. In some embodiments the void filling protrusion <NUM> can also be filled with matter to enhance or cause solidification of the bone matter outward of the stemless humeral anchor 10A and within the void filling protrusion <NUM>. For example, the void filling protrusion <NUM> can include a porous shell <NUM>. Although the overall structure of the bone filling protrusion <NUM> can be a three dimensional projection from one or more of the arms <NUM> or another part of the anchor 10A, at least a portion thereof is mesh-like. <FIG> is a schematic representation of this mesh-like portion. The porous shell <NUM> can include a mesh of any suitable scale. The mesh-like structure enables the anchor 10A to retain the intended form of the protrusion <NUM> due to the construction there, but provides small gaps as illustrated in <FIG> that allow for a substance that will enhance integration with native bone by being disposed within the bone filling protrusion <NUM> but being able to be pressed out through the mesh-like portion into contact with the native bone or otherwise become in direct contact with the native bone. Generally the porous shell <NUM> is configured to retain a bone void filling component <NUM> but to allow the cancellous bone to extend across the porous shell <NUM>. The porous shell <NUM> can be configured with a thickness in a range of <NUM> to <NUM>. The porous shell <NUM> can be configured with a thickness in a range <NUM> to <NUM>. The porous shell <NUM> can be configured with a thickness in a range <NUM> to <NUM>. Also, the pores that can be found in the porous shell <NUM> can be small enough to retain the porous shell <NUM> but large enough to permit bone growth across the porous shell <NUM>.

<FIG> illustrates the bone void filling component <NUM> disposed within and contained by the porous shell <NUM>. A kit can be provided to form the combination shown in <FIG>. The kit can include the stemless humeral anchor 10A (or other humeral anchor including void filling protrusion <NUM>) and the bone void filling component <NUM>. The bone void filling component <NUM> can be any suitable matter that either forms a sufficiently solid volume within, through, and/or around the stemless humeral anchor 10A (or other humeral anchor including the void filling protrusion <NUM>). The bone void filling component <NUM> can include an autograft (prepared from the patient's own bone), an allograft, or any suitable synthetic biologic materials such as a sulfate-calcium phosphate composite or a combination of recombinant human platelet derived growth factor BB (rhPDGF-BB) and Beta tri-calcium phosphate (β-TCP) granules as non-limiting examples.

<FIG> shows that in some embodiments the stemless humeral anchor <NUM> can be patient specific through a variety of parameters. The stemless humeral anchor <NUM> is patient specific in providing at least one enlarged arm 22A. The stemless humeral anchor <NUM> also is patient specific in having a void filling protrusion <NUM> to make solid or otherwise enhance the bone mass beneath the face F. The stemless humeral anchor <NUM> can be further configured to be patient specific in other aspects, as are discussed herein.

<FIG> show additional embodiments in which a stemless humeral anchor can be made patient specific. For example, <FIG> shows a stemless humeral anchor 10B that is similar to the stemless humeral anchor 10A except as described differently below. The stemless humeral anchor 10B includes a plurality of arms 22B that are coupled with a first end <NUM> of a mating portion <NUM> of the stemless humeral anchor 10B. The arms 22B each extend out from the first end <NUM> and curve toward the second end <NUM> of the stemless humeral anchor 10B. The arms 22B are different from the arms <NUM> in that they have a span adjacent to the second end <NUM> of the stemless humeral anchor 10B that is spaced apart from the mating portion <NUM> by a gap region. The stemless humeral anchor 10B includes a collar 20B that is patient specific in at least one manner. For example, the collar 20B can have a transverse or lateral extent that is based on the size of a perimeter RP at the resection plane. If the collar 20B has a circular outer periphery the transverse extent can include a radius that is tangential to the point of the perimeter RP closest to the center of the face F where the stemless humeral anchor 10B is to be implanted. In this manner, the most extensive coverage of the round collar 20B can be provided to the face F. As discussed more below in connection with <FIG> any of the collars described herein can be a shape other than round, such as an organic shape that follows the perimeter RP, e.g., maintaining a preferred annular space between the outer periphery of the collar and the perimeter RP. <FIG> shows the collar 20B extending radially outward of the articular component <NUM> for illustrative purposes. In many cases, the collar 20B will have a radius (or transverse size) that is equal to or somewhat less than the radius of the lateral side of the articular component <NUM>.

<FIG> illustrates another embodiment of a stemless humeral anchor 10C that can include any of the features of other press-fit stemless implants discussed herein. The stemless humeral anchor 10C can include a plurality of arms 22C that can have a generally tapered frame profile. The arms 22C can be narrower toward the first end <NUM> and wider toward the second end <NUM> of the stemless humeral anchor 10C. The frame profile of the arms 22C can include a rigid outer periphery that surrounds an open central area. The stemless humeral anchor 10C can include one or more augmented arms 22A. The augmented arms 22A can be configured in a patient specific manner in which a dimension or portion of the arms 22A can be enlarged compared to the arms 22C. The arms 22A can extend a greater amount laterally, e.g., away from a mating portion <NUM> of the stemless humeral anchor 10C to engage a more voluminous portion of the humerus H distal of the face F (see <FIG>). The stemless humeral anchor 10C can have a collar <NUM> that can be generic to all patients in some embodiments. In other embodiments the collar <NUM> can also be patient specific, e.g., enlarged for patients with larger humeral heads to reduce, minimize or eliminate stress shielding.

<FIG> shows another stemless humeral anchor 10D that is similar to those discussed above except as described differently. The stemless humeral anchor 10D has at least one portion that is adapted for a specific patient upon pre-operative imaging. The stemless humeral anchor 10D includes a void filling protrusion <NUM> that is coupled with a collar <NUM>. The collar <NUM> is disposed at the second end <NUM> of the stemless humeral anchor 10D. The void filling protrusion <NUM> projects from the second end <NUM> toward the first end <NUM>. The void filling protrusion <NUM> can be formed contiguously with a mating portion <NUM>. The mating portion <NUM> can be formed in a central zone of the stemless humeral anchor 10D, e.g., projecting into the central zone of the portion of the stemless humeral anchor 10D to be disposed beneath the face F. The stemless humeral anchor 10D can include a plurality of arms 22D. The arms 22D can be of similar configuration to each other, e.g., can be generic to all or a class of patients. One or more of the arms 22D can be patient specific, e.g., having a greater extent in one or more directions than the other arms 22D to extend into more voluminous bone matter in a specific area. In some embodiments the arms 22D can have a fixed end coupled with the collar <NUM> and a free end spaced away from the fixed end. The free end can be sharp enough to be urged into cancellous bone. The length of the arms 22D can include one or more ribs, ridges, barbs, or other engagement features for coupling securely to the cancellous bone. The void filling protrusion <NUM> can be contiguous with one or more of the arms 22D or can be spaced apart from all of the arms 22D. The void filling protrusion <NUM> will be coupled directly or indirectly with the collar <NUM>. The collar <NUM> can be enlarged to be the larger than, the same as, or nearly as large as the lateral sides of the articular component <NUM> to reduce, minimize or eliminate stress shielding at the face F.

<FIG> shows a stemless humeral anchor 10E that can include any of the features of any of the other anchors disclosed herein. The stemless humeral anchor 10E includes a second end <NUM> configured to be disposed at the face F. The stemless humeral anchor 10E includes a first end (not shown) but in <FIG> the stemless humeral anchor 10E is illustrated in the resected head of the humerus H so the first end is embedded in the bone and not shown. The first end can be similar to that of any of the foregoing anchors. The stemless humeral anchor 10E has a mating portion <NUM> that is accessible from the second end <NUM>. A recess <NUM> is formed in the mating portion <NUM>. The recess <NUM> is configured to receive a projection of an articular component to mate therewith. The recess <NUM> and the mating portion <NUM> extend along a longitudinal axis LA as shown. The stemless humeral anchor 10E includes a collar 20E that is adapted for a specific patient based upon pre-operative characterization, e.g., imaging as discussed above.

The collar 20E extends transverse to the longitudinal axis LA toward an outer periphery of the stemless humeral anchor 10E. The outer periphery of the collar 20E is configured to reduce stress shielding. For example the collar 20E can have a shape that closely matches the shape of the perimeter RP of the face F at the resection plane of the humerus H. In addition to matching the shape of the perimeter RP the collar 20E can match the size of the perimeter RP, e.g., can be large enough to extend to or nearly to the perimeter RP of the face F when the stemless humeral anchor 10E is coupled with the specific patient's humerus H. In one embodiment, the collar 20E is configured such that when properly applied to the patient a maximum gap threshold is not exceeded. In other words, the collar 20E can be configured to achieve a maximum gap below a specific amount. The maximum gap can be applied to a zone of the humerus H that is subject to erosion due to stress shielding as discussed in connection with <FIG>. In some cases, the maximum gap can be applied to the entire circumference of the stemless humeral anchor 10E. In other embodiments, the collar 20E can allow for lager gaps between the outer periphery thereof and the perimeter RP of the face F in zones not subject to stress shielding erosion but can be configured to assure a gap of less than <NUM> therebetween at the medial calcar MC or other zone that is subject to stress shielding erosion. In certain embodiments, the collar 20E is configured to assure a gap of less than <NUM> between the outer periphery thereof and the perimeter RP of the face F at the medial calcar MC or other zone that is subject to stress shielding erosion. In certain embodiments, the collar 20E is configured to assure a gap of less than <NUM> between the outer periphery thereof and the perimeter RP of the face F at the medial calcar MC or other zone that is subject to stress shielding erosion.

<FIG> shows that the perimeter RP can be rotationally asymmetric. That is, anterior and posterior halves of the perimeter RP need not match each other. Thus, the placement of the stemless humeral anchor 10E should be rotationally aligned for the specific patient. If proper rotational alignment is not provided, the eccentric shape of the collar 20E will not properly match that of the perimeter RP of the face F. Accordingly, in methods of applying the stemless humeral anchor 10E care should be taken so that the rotational position of the collar 20E to the perimeter RP is properly provided.

<FIG> and <FIG> show the shoulder assembly <NUM> applied to a shoulder joint. As discussed below in connection with <FIG>, at least a portion of the assembly 100B and various modified embodiment thereof can be adapted for a specific patient based upon pre-operative analysis of that patient's bone, e.g., CT scan, MRI, or X-ray. The assembly 100B can provide secure stemless connection to the humerus H. The shoulder assembly 100B provides for simple implantation because a base member thereof can be directly threaded into cancellous bone without being mated to another pre-placed base member. The shoulder assembly 100B can be fully retained within a head h of the humerus H. <FIG> shows that the distal-most portion of the assembly <NUM> preferably can be disposed in the humeral head h. The assembly <NUM> does not have a stem or other member that protrudes beyond the head h into a medullary canal of the humerus. This approach is less invasive and simpler than procedures involving placement of a stem in a medullary canal. In other embodiments illustrated in part in <FIG> by the creation of a recessed surface S having a depth accommodating a thickness of a proximal portion of the assembly <NUM>, the assembly <NUM> may be recessed within the humeral head of the humerus H such that a proximal face <NUM> the assembly <NUM> is flush with respect to a cut surface of the bone. In other embodiments discussed herein a proximal portion of a humeral assembly can be configured to be assembled onto the resection surface following a patient specific resection as discussed in connection with <FIG>.

<FIG> shows that the assembly <NUM> includes a base member <NUM> and a locking device <NUM>. The base member <NUM> is advanced into a bony structure such as cancellous bone in use. As discussed further below a bone surface may be exposed by resection or reaming, followed by threading of the base member <NUM> into a newly exposed bone surface. The assembly <NUM> also includes the locking device <NUM>. The locking device <NUM> includes a plurality of arms <NUM>. In particular, the arms <NUM> extend outward or distal from proximal support <NUM>. The arms <NUM> can include a first arm, a second arm, and a third arm. The arms <NUM> can be circumferentially spaced equal distances from each other, e.g., about <NUM> degrees apart in one embodiment. In another variation, the arms <NUM> include three arms, with two of the three arms spaced <NUM> degrees from each other and a third arm spaced <NUM> degrees from one of the other two arms. The locking device <NUM> may include four or more arms <NUM>. If the arms <NUM> include four arms, the arms can be circumferentially spaced <NUM> degrees apart. If the arms <NUM> include two arms, the arms can be circumferentially spaced <NUM> degrees apart. The arms <NUM> are advanced through apertures <NUM> in the base member <NUM>. In one embodiment, it should be noted that the number of arms <NUM> corresponds to an equal number of apertures <NUM>. When so advanced, the arms <NUM> are disposed within the base member <NUM> in a manner that the arms <NUM> cross a space between portions, e.g., successive portions, of the base member <NUM>. When so positioned, the arms <NUM> are also disposed within bone. Thus, two zones of the arms <NUM> can cross successive or adjacent portions of the base <NUM> and an intervening portion of the arms <NUM> can cross bone in a space between the successive or adjacent portion of the base. In this position, the arms <NUM> control, e.g., resist, rotation of the base member <NUM> relative to the bone such that the shoulder assembly <NUM> is secured against backing out of the bone upon implantation.

<FIG> also shows that the locking device <NUM> also includes a proximal support <NUM>. The proximal support <NUM> is coupled with the arms <NUM> in a manner discussed further below. The proximal support <NUM> has a central aperture <NUM> disposed within an inner periphery thereof and extends outward from the central aperture <NUM> to an outer periphery <NUM>. The inner and outer periphery of the proximal support <NUM> are received in a recess <NUM> formed in the base member <NUM>. In one configuration the recess <NUM> and the proximal support <NUM> are configured such that a flush connection is provided between the proximal support <NUM> and the proximal face of the base member <NUM>. The proximal support <NUM> can be connected to the base member <NUM> in an at least partially recessed position in the proximal face of the base member as discussed further below in connection with <FIG>.

<FIG> and <FIG> show that the proximal face of the base member <NUM> can include a raised inner portion <NUM> and a raised outer portion <NUM>. The outer raised portion <NUM> extends around an outer periphery <NUM> of the base member <NUM>. The raised portion <NUM>, <NUM> are proximally oriented projections relative to a recessed surface <NUM>. The recessed surface <NUM> can be disposed distally of one or both of the inner portion <NUM> and the outer portion <NUM>. The raised inner portion <NUM> can define an aperture for access into the recess <NUM>, which is configured for mating with articular components as discussed below. Each of the raised inner portion and the raised outer portion <NUM>, <NUM> can comprises annular structures. The recessed surface <NUM> can comprise an annular portion. The apertures <NUM> can be formed in the recessed surface <NUM>. In one embodiment the apertures <NUM> extend radially between the inner raised portion <NUM> and the outer raised portion <NUM>. The apertures <NUM> can extend from the inner raised potion <NUM> to the outer raised portion <NUM>.

The proximal face of the base member <NUM> also can include a tool interface <NUM> that enables the base member to be advanced by an inserter into bone, as discussed below in <FIG>. The tool interface <NUM> includes three notches in an inward side of the outer raised portion <NUM>. In other embodiments, the tool interface <NUM> can include apertures in the recessed surface <NUM>, notches in the inner raised portion <NUM>, projections from any surface of the proximal face of the base member <NUM> or any combination of these features. Also, the tool interface <NUM> can provide access for a removal tool to engage the locking device <NUM>. As discussed below, the locking device <NUM> includes a spring arm <NUM> and a removal tool can be applied at the tool interface <NUM> to compress the arm <NUM> to disengage the locking device from the base member <NUM>. In some cases, an inserter tool can engage one or more apertures <NUM> in the base member <NUM> upon insertion.

One or more structures for securing the locking device <NUM> to the base member <NUM> can be provided as discussed further below. For example the locking device can have an engagement feature <NUM> disposed on the proximal support <NUM> that is adapted to engage a corresponding feature on the proximal face of the base member <NUM>. The engagement feature <NUM> can include an actuatable member that can move into a secure position relative to the recess <NUM> of the base member <NUM>. As discussed below in connection with <FIG> and <FIG>, the engagement features <NUM> can include a spring arm <NUM> to engage an overhang of the recess <NUM>. As shown in <FIG>, one embodiment comprises a plurality of actuatable members, e.g., a plurality of spring arms <NUM>. The spring arms <NUM> can be spaced apart, e.g., providing equal angle separation between adjacent spring arms <NUM>. In one embodiment, the number of spring arms <NUM> matches the number of arms <NUM>. Each spring arm <NUM> can be spaced apart from each arm <NUM> as discussed further below.

In another embodiment, a serration <NUM> is provided between the arms <NUM> of the locking device <NUM> and the base member <NUM> as discussed in greater detail below in connection with <FIG>. The serration <NUM> is an example of a one-way connection that can be provided between the arms <NUM> and the base member <NUM>. Other one-way connections can be provided in addition or in place of the serration <NUM>, such as a ratchet, a barb, or one or more spring arms.

<FIG> show further details of embodiments of the base member <NUM>. In some embodiments, the base member <NUM> can include various features described in <CIT>. The base member <NUM> has a first end <NUM>, a second end <NUM> and a body <NUM> that extends between the first end <NUM> and the second end <NUM>. The base member <NUM> can comprise a length L between the first end <NUM> and the second end <NUM> that is less than a dimension of an articular surface of typical epiphysis to a medullary canal of a typical humerus. As such, the first end <NUM> can be disposed within the epiphysis when the second end <NUM> is at a surface of the bone, as shown in <FIG>. The second end <NUM> can be disposed at or on a superior medial resection plane of a humerus while the first end <NUM> is well within the epiphysis. This enables the first end <NUM> to stop short of a medullary canal of the humerus when the base <NUM> is fully implanted, which allows the bone between the first end <NUM> and the medullary canal to remain unaltered and also simplifies the procedure to the extent that any normal access to and preparation of the medullary canal is not needed. In various embodiments, the length L can be between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>. The length L can be about <NUM>, about <NUM> about <NUM>, about <NUM>, mm about <NUM> and about <NUM>. In one approach, at least a portion of the assembly <NUM> is patient specific. For example, the length L can be defined for a specific patient based on pre-operative planning, such as using two dimensional or three dimensional imaging. The base member <NUM> can thereafter be manufactured for that patient based on the determined dimension L.

The base member <NUM> can include a collar <NUM> and a helical structure <NUM>. The helical structure <NUM> is disposed about a cylindrical portion <NUM> of the body <NUM> of the base member <NUM>. In some embodiments, the helical structure <NUM> extends directly from the body <NUM> and may be considered threads of the body <NUM>. The helical structure <NUM> can include one or a plurality of threads, e.g., two, three, four, or more threads, disposed between the first end <NUM> and the second end <NUM>. The threads can start adjacent to the first end <NUM> and extend toward, e.g., entirely to the second end <NUM>. <FIG> shows that the threads or other helical structure <NUM> can end at or adjacent to the collar <NUM>. The threads or other helical structure <NUM> can have inner portions <NUM> disposed at or on the body <NUM> about the recess <NUM> and outer portions <NUM> disposed along the periphery of the base <NUM>. <FIG> shows that the helical structure <NUM> has a width defined as the distance between the inner and outer portions <NUM>, <NUM> that is large, e.g., comprising more than one-quarter of, e.g., about one-third of, the width of the base <NUM> at a given location. These large threads or other helical structure <NUM> ensure large purchase in the bone. Large purchase provides strong resistance to pullout even prior to any bone ingrowth into the surfaces of the shoulder assembly <NUM>. Generally one or more surfaces of the shoulder assembly <NUM> that are in direct contact with bone may be textured e.g., coated or layered with a porous material in order to accelerate tissue ingrowth such as bony ingrowth Therefor good initial resistance to pull-out is advantageous for the patient. At least one turn of a thread or other helical structure <NUM> completely surrounds the recess <NUM>, e.g., by completely surrounding the body <NUM>, in some embodiments.

<FIG> show that additional features of the base <NUM> can be made patient specific. <FIG> shows a base 104A with a first end <NUM>, a second end <NUM> and a body <NUM> that extends between the first end <NUM> and the second end <NUM>, similar to the base <NUM> discussed above. The base 104A has a helical structure 224A that is made patient specific. That is, pre-operative information such as CT scan, MRI scan, X-ray or other assessment of the proximal humerus is conducted. That assessment can reveal patient specific characteristics of the portion of the proximal humerus to which the base 104A will be coupled. For example, that assessment can identify the location of a resection along the humerus H (see <FIG>) or volume, density, or location of bone between the exposed face F and the medullary canal or the lateral side of the proximal humerus. Based on this information, the configuration of the body <NUM> can be altered. For instance the helical structure 224A can comprise threads that have a smaller thread pitch than is provided in the threads of the helical structure <NUM>. Smaller thread pitch is suitable for a patient having denser than average bone matter disposed beneath the exposed face F. The thread pitch can be in the range of <NUM>-<NUM> depending on the bone quality. A thread pitch of <NUM> could be suitable for average bone density. A thread pitch of <NUM> could be suitable for high bone density. A thread pitch of around <NUM> could be suitable for lower bone density. The helical structure 224A can have a transverse extent (e.g., from the inner portions <NUM> to the outer portions <NUM> thereof that is larger than in the helical structure <NUM>. In one form the maximum transverse extent in the helical structure 224A is greater than the maximum transverse extent in the helical structure <NUM>. Larger transverse extent is suitable for a patient having poor bone quality, larger humeral heads, e.g., with larger surface area at the exposed face F and/or with greater volume of bone beneath the exposed face F. For example, the transverse extent could be in a range of between <NUM> and <NUM> depending on the patient. A patient with a smaller humeral head might have a transverse extent of about <NUM>. A patient with a larger humeral head might have a transverse extent of about <NUM>. <FIG> shows a base 104C that also can be made for a specific patient based on pre-operative analysis of the patient's bone. A helical structure 224C can be formed or shaped in a patient specific manner. The helical structure 224C can extend from a first end <NUM> and to a second end <NUM> of the base 104C. The form of the helical structure 224C can change between the first end <NUM> and the second end <NUM>. For example, the transverse extend of each successive turn can be selected based upon the patient's bone disposed laterally and inferiorly of the exposed face F to be formed by resection. If the perimeter of the humeral head in planes adjacent and parallel to the exposed face F in the direction of the arrow A in <FIG> rapidly reduces a profile <NUM> can be formed to match that rapid change. If the perimeter of the humeral head in planes parallel to the exposed face F in the direction of the arrow A in <FIG> more gradually reduces a profile <NUM> can be formed to match that more gradual change. Thus, the profile <NUM> of the helical structure 224C can be made patient specific to enhanced fixation to the bone and/or to avoid over-filling the humeral head with the helical structure.

The body <NUM> surrounds the recess <NUM>, which is configured to mate with an articular component, such as humeral head or a glenoid sphere. In one embodiment, the body <NUM> includes a cylindrical portion <NUM> within which the recess <NUM> is disposed. The cylindrical portion <NUM> can have any suitable outside configuration, such as including a textured surface that is well suited to encourage bony ingrowth. The cylindrical portion <NUM> can include a generally tapered profile in which a portion at or adjacent to the first end <NUM> of the base member <NUM> has a first width and a portion at or adjacent to the second end <NUM> of the base member <NUM> can have a second width, the second width being greater than the first width. In some embodiments, the cylindrical portion <NUM> is generally rounded and formed a blunt but tapered profile. The cylindrical portion <NUM> can have a flat distal surface in some embodiments.

<FIG> shows that the cylindrical portion <NUM> can include a plurality of layers. For example, an inner layer <NUM> can be disposed adjacent to the recess <NUM>. The inner layer <NUM> can include the surface surrounding the recess <NUM> and can extend away from that surface toward an outer surface of the cylindrical portion <NUM>. In one embodiment an outer layer <NUM> can be disposed adjacent to the outer surface of cylindrical portion <NUM>. The outer layer <NUM> can extend from the external surface of the cylindrical portion <NUM> toward the recess <NUM>. In one embodiment, the outer layer <NUM> is formed directly on the inner layer <NUM> although other arrangements are possible as well. The outer layer <NUM> can be a porous structure that is suitable for bony ingrowth.

<FIG> also shows that a tool interface <NUM> can be disposed at or adjacent to the first end <NUM> of the base member <NUM>. The tool interface <NUM> can include a threaded portion that can mate with a delivery tool, as discussed further below. A lumen <NUM> can be provided at the first end <NUM> such that access can be provided from the first end <NUM> through the wall of the cylindrical portion <NUM> into the recess <NUM>. The lumen <NUM> and recess <NUM> together provide access for a K-wire or other guiding device such that implanting the base member <NUM> can be controlled in an appropriate manner.

The collar <NUM> can be disposed at or can comprise the second end <NUM> of the base member <NUM>. The collar <NUM> can have a transverse width, e.g., a diameter that is suitable for a given condition. For example, the diameter of the collar <NUM> can be selected such that the entire outer periphery of the base <NUM> is within the bone exposed by resection and/or recessed into such an exposed bone portion, e.g., as illustrated in <FIG>. In some embodiments the collar <NUM> has a diameter of more than about <NUM> and less than about <NUM>. The collar <NUM> can have a diameter of between about <NUM> and about <NUM>. The collar <NUM> can have a diameter of about <NUM> in one embodiment. The collar <NUM> can have a diameter of about <NUM> in one embodiment. Making the collar <NUM> as large as possible within such bounds provides for better load transfer between the collar <NUM> and the humerus H. In one approach, the diameter of the collar <NUM> can be defined for a specific patient based on pre-operative planning, such as using two dimensional or three dimensional imaging. The base member <NUM> can thereafter be manufactured for that patient based on the determined diameter of the collar. For example, the diameter of the collar <NUM> can be selected such that the collar covers the cortical rim exposed by resection. The collar <NUM> can attach to or can be integrally formed with the cylindrical portion <NUM> of the body <NUM>. In one embodiment the collar <NUM> comprises a transverse flange <NUM> that extends outward of the recess <NUM> that is also disposed at the second end <NUM>. An inner portion of the flange <NUM> can be disposed adjacent to the recess <NUM> and can include the inner raised portion <NUM>. An outer portion of the flange <NUM> can be disposed outward of the inner portion. The flange <NUM> can define the proximal face of the base member <NUM>. The flange <NUM> can accommodate the proximal support <NUM> of the locking device <NUM>. <FIG> shows that in some embodiments, the flange <NUM> can at least partially surround a space <NUM> disposed therein to receive a portion of the locking device <NUM>. The space <NUM> can be an annular recess located proximal of the recessed surface <NUM> and between the inner portion <NUM> and the outer portion. The space <NUM> can be bounded by an inner edge of the outer portion <NUM> and an outer edge of the inner portion <NUM>. The flange <NUM> can engage the spring arm <NUM> of the locking device <NUM> in the space <NUM> such that the locking device <NUM> will not be inadvertently disengaged from the base <NUM> and protrude from or be removed from the space <NUM>.

<FIG> and <FIG> show that in some embodiment, the shoulder assembly <NUM> includes a pathway <NUM> that projects distally of the collar <NUM>. The pathway <NUM> can comprise a first pathway. The shoulder assembly <NUM> can include a plurality of pathways, <NUM> with each pathway corresponding to an arm <NUM> of the locking device <NUM>. <FIG> shows that the base <NUM> can define a plurality of such pathways, e.g., two or three pathways configured to receive corresponding arms <NUM>. There can be four or more than four pathways <NUM>. The pathway <NUM> can have a first end located at the opening or apertures <NUM> in the collar <NUM>. The pathway <NUM> can continue down through the base member <NUM>. <FIG> shows that the pathway <NUM> can have one or more segments disposed through the helical structure <NUM>. A first segment 300A of the pathway <NUM> extends from the aperture <NUM> to a first portion, e.g., a proximal-most turn or portion of the helical structure <NUM> immediately distal of the collar <NUM>, e.g., immediately distal of one of the apertures <NUM>. A second segment 300B of the pathway <NUM> extends from the first segment 300A to a second turn or portion of helical structure <NUM> immediately distal of the first portion of the helical structure. A third segment 300C of the pathway <NUM> can extend from the second segment to a third turn or portion of helical structure <NUM> immediately distal of the second portion of the helical structure <NUM>.

<FIG> and <FIG> illustrate that at specific locations along the length of the base <NUM> from the first end <NUM> to the second end <NUM>, the pathway <NUM> can have a first boundary <NUM> corresponding to an outer surface or layer of the cylindrical portion <NUM>, for example corresponding to a surface of the outer layer <NUM>. The pathway <NUM> can have a second boundary <NUM> at a same location along the length of the base <NUM> from the first end <NUM> to the second end <NUM> formed by an adjacent portion of helical structure <NUM>. The second boundary <NUM> can include a U-shaped opening in the inner portion <NUM> of the helical structure <NUM>. The U-shaped opening in the inner portion <NUM> can extend across the width of the helical structure toward the outer portion <NUM> of the helical structure <NUM>. The U-shaped opening can extend <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>% or up to <NUM>% of the distance across the width of the helical structure <NUM> from the inner portion <NUM> toward the outer portion <NUM>. In one embodiment, the helical structure <NUM> has a tapered configuration in which transverse distance between opposite sides of the helical structure <NUM> is decreased in the direction of the first end <NUM> compared to the same dimension toward the second end <NUM>. The length of the U-shaped opening in successive portions of the helical structure <NUM> in the direction toward the first end <NUM> is progressively less in some embodiments. As a result the width bounded by a turn of the helical structure <NUM> and the cylindrical portion <NUM> in the first segment 300A of the pathway <NUM> can be greater than the width bounded by a turn of the helical structure <NUM> and the cylindrical portion <NUM> in the second segment 300B. The width in the second segment 300B can be greater than the width in the third segment 300C bounded by a turn of the helical structure <NUM> and the cylindrical portion <NUM>. This configuration is advantageous in accommodating embodiments of the locking device <NUM> having arms <NUM> that are tapered as discussed further below.

The pathway <NUM> can extend through one or more spaces between adjacent threads of the helical structure <NUM>. The pathway <NUM> can comprise two or more segments surrounded by portions of the base member <NUM> and at least one exposed segment ES. The exposed segments comprise portions of the first and second segments 300A, 300B and between the second and third segments 300B, 300C in some embodiment. The exposed segments ES are exposed in that, unlike the segments 300A, 300B, 300C, the exposed segments of the pathway <NUM> are not enclosed circumferentially and thus bone disposed within the helical portion <NUM> can directly contact the arms <NUM> in the exposed segment. As such the pathway <NUM> is bounded by bone matter in the exposed segments.

<FIG>, <FIG> and <FIG> show the locking device <NUM> in detail. As discussed above, the locking device <NUM> has a proximal support <NUM> and a first arm <NUM> that projects distally of the proximal support <NUM>. The proximal support <NUM> includes an inner periphery <NUM>, an outer periphery <NUM> and an annular member <NUM> disposed therebetween. The inner periphery <NUM> surrounds the central opening <NUM>, which is sized to receive the inner raised portion <NUM> of the base member <NUM> if present. The annular member <NUM> is configured to be received in the recess <NUM>, as discussed above.

The first arm <NUM> is configured to be disposed in the first pathway <NUM>. The pathway <NUM> projects distally of the collar <NUM>. The first arm <NUM> is disposed distal of the collar <NUM> when the proximal support <NUM> is disposed adjacent to a proximal side of the collar <NUM> and the first arm <NUM> is in the first pathway <NUM>.

The first arm <NUM> includes an outer edge <NUM>, an inner edge <NUM> and a span <NUM> disposed therebetween. The first arm <NUM> includes a first end <NUM> disposed away from the support <NUM> and a second end <NUM> disposed adjacent to and in some cases directly coupled to the support <NUM>. The first arm <NUM> can be tapered, for example with the outer edge <NUM> approaching the inner edge <NUM> in the direction toward the first end <NUM> and/or with the outer edge <NUM> diverging away from the inner edge <NUM> in the direction toward the second end <NUM>. In one embodiment, opposite faces <NUM> of the span <NUM> are also tapered with at least one of, e.g., both of, the opposite faces <NUM> approaching a longitudinal mid-plane M of an arm <NUM>. The tapering of the arms between the edges <NUM>, <NUM> facilitates providing a tapered profile in the base member <NUM>. The tapering of the arms between the edges <NUM>, <NUM>, sometimes referred to herein as a radial taper, facilitates insertion of the first end <NUM> into the aperture <NUM> because the first end <NUM> is much narrower in the dimension between the edges <NUM>, <NUM> than the aperture <NUM> is in the radial direction. The tapering of the arms <NUM> between the faces <NUM>, sometimes referred to herein as a circumferential taper, facilitates insertion of the first end <NUM> into the aperture <NUM> because the first end <NUM> is much narrower in the dimension between the faces <NUM> than the aperture <NUM> is in the circumferential direction.

At least one of the circumferential and radial tapers of the arms <NUM> enables the locking device <NUM> to easily be advanced through bone matter that is disposed along the pathway <NUM>.

As discussed above, the first arm <NUM> is disposed through bone in the space between successive portions of the helical structure <NUM>, e.g., in the first segment of the path <NUM> and in the second segment of the path <NUM>, when the humeral shoulder assembly is implanted. The span <NUM> and/or other parts of the arms <NUM> can be porous to enhance bony ingrown when the assembly <NUM> is implanted. The porous properties can be provided by a porous metal surface or structure or by other porous layers disposed on an underlying layer of metal or another material. At least the widening of the arms <NUM> toward the second end <NUM> increases the purchase of bone in the widened area, e.g., in the first segment of the path <NUM> and also in the second segment of the path <NUM> compared to an arm that is not tapered.

In some embodiments, the arms <NUM> are not tapered in the radial direction. For example the arms <NUM> can have a constant radial dimension between the edges <NUM> and <NUM> at a length between, e.g., along the entire length between, the first end <NUM> and the second end <NUM>. In some embodiments, the arms <NUM> are not tapered in the circumferential direction. For example the arms <NUM> can have a constant circumferential dimension between the first end <NUM> and the second end <NUM>.

As discussed above, the locking device <NUM> facilitates retaining the base member <NUM> in the bone at least by opposing, and in some cases completely preventing, rotation of the base member that would cause the base member to back out of the bone into which it has been advanced. Additionally, in some embodiments, it is beneficial to oppose, and in some cases completely prevent, axial movement of the locking device <NUM> away from the base member <NUM>. At the extreme, such movement could result in the arms <NUM> of the locking device <NUM> completely coming out of the pathways <NUM> and, indeed, out of the base member <NUM> completely. It also may be desirable to prevent even lesser movements of the locking device <NUM> relative to the base member <NUM>. As shown in <FIG>, a distal face <NUM> of the annular member <NUM> may be positioned in direct contact with a proximal face <NUM> of the transverse flange <NUM>. Such contact can correspond to a proximal face <NUM> of the annular member <NUM> being distal of a proximal face <NUM> of the raised outer portion <NUM>. By recessing the annular member <NUM>, the interaction of the assembly <NUM> with the articular member of the kit <NUM> of <FIG> is controlled. For example, the annular member <NUM> will not impede advancement of the articular members into secure engagement with the recess <NUM>.

<FIG> and <FIG> illustrate various embodiments of axial locking configuration that can be provided in the shoulder assembly <NUM>. An axial locking configuration can include the engagement feature <NUM> disposed on the proximal support <NUM>. The spring arm <NUM> of the engagement feature can include a first end <NUM> disposed away from the annular member <NUM> and a second end <NUM> coupled with the annular member <NUM>. The spring arm <NUM> also has an elongate portion <NUM> that extends between the first end <NUM> and the second end <NUM>. The elongate portion <NUM> preferably has an arcuate form and can, in some embodiments, have the same curvature as a portion of the annular member <NUM> adjacent to the second end <NUM>. The elongate portion <NUM> can be separated from the annular member <NUM> along a radially inner edge <NUM> of the elongate portion <NUM> by a gap G. The gap G and the length of the elongate portion <NUM> can be such that the first end <NUM> can be moved sufficiently to allow for a snap-fit connection as discussed further below. In one embodiment, the first end <NUM> of the spring arm <NUM> has a deflector <NUM> that facilitates movement of the elongate portion <NUM> and specifically movement of the first end <NUM>. <FIG> shows that the deflector <NUM> can include an angled surface <NUM> that initially engages a corresponding angled surface <NUM> on the base member <NUM>, e.g., on the raised outer portion <NUM> at the proximal face of the base member. As the arms <NUM> of the locking device <NUM> are advanced into the paths <NUM>, the annular member <NUM> eventually is received in the space <NUM>. At that time, the angled surfaces <NUM>, <NUM> engage each other, which engagement causes the deflection of the first end <NUM> of the spring arm <NUM>. The first end <NUM> is deflected radially inwardly such that the gap G is reduced at least at the first end <NUM>. This allows a proximal facing surface <NUM> to move to a position distal of a distal facing surface <NUM>. After the proximal facing surface <NUM> is at a position distal of the distal facing surface <NUM>, the spring arm <NUM> resiliently moves the deflector <NUM> back to the configuration shown in <FIG>. At this point, the proximal facing surface <NUM> is distal of and aligned with, e.g., positioned under, the distal facing surface <NUM>, as shown in <FIG>. In this configuration, the proximal facing surface <NUM> blocks the distal facing surface <NUM> from moving proximally. Thus the surfaces <NUM>, <NUM> prevent the locking device <NUM> from disengaging from the base member <NUM>.

Another advantageous aspect of the assembly <NUM> is that the locking device <NUM> can be quickly and easily disengaged from the base <NUM>. The tooling interface <NUM> allows an extraction tool to be disposed between the raised outer portion <NUM> and the spring arm <NUM>. The extraction tool can apply a radially inward force on an outer periphery of the elongate portion <NUM> of the spring arm <NUM>. Compression of the spring arm <NUM> decreases the gap G as the proximal facing surface <NUM> is moved radially inward of the distal facing surface <NUM>. Once the first end <NUM> is entirely radially inward of the distal facing surface <NUM>, the engagement feature <NUM> is disengaged from the base <NUM>. If more than one spring arm <NUM> is provided some or all of the spring arms can be compressed to allow the locking device <NUM> to be withdrawn from the base <NUM>.

<FIG> shows additional axial locking configurations that can be provided in the shoulder assembly <NUM>. In these embodiments, axial locking can occur at an interface <NUM> between one or more of the arms <NUM> and one or more of the pathways <NUM>. For example, the serrations <NUM> discussed above can be provided at the interface. In one variation, serrations <NUM> are disposed along the pathway, e.g., on a surface of the cylindrical member <NUM> and/or on a surface of the helical structure <NUM>. The serrations <NUM> can be placed at both the surface of the cylindrical member <NUM> and at the helical structure <NUM>. In another embodiment, the serrations <NUM> could be provided on a surface of the arm <NUM>, e.g., on one of the outer edge <NUM>, the inner edge <NUM>, and/or on one of the faces <NUM>. The serrations <NUM> allow for relatively easy insertion of the arms <NUM> but bite into and oppose withdrawal of the locking device <NUM> to oppose axial disengagement of the locking device <NUM> from the base member <NUM>.

The serrations <NUM> can be disposed along the entire length of the interface between the arms <NUM> and the base member <NUM> or just at a position where the base member <NUM> and the locking device <NUM> are fully engaged.

<FIG> illustrate various techniques for implanting the shoulder assembly <NUM> in a humerus H. The method illustrates placement in a proximal end of the humerus H, e.g., in the humeral head h.

<FIG> illustrates an early step of one embodiment of a method including resecting the head h of the humerus H. Prior to resecting the head h of the humerus H a guide <NUM> is applied to the humerus H. The guide <NUM> includes structure for mating with the humerus H and the head h, for example, a plate <NUM> to mate with the humerus H and pins <NUM> to mate with the head h. The guide <NUM> also has a slot <NUM> to guide a saw to cut the humerus H to expose cancellous bone of the head h. <FIG> shows that after resecting the head h of the humerus H the size of the head is evaluated with a template <NUM>. To obtain a quick and accurate sizing, a guide pin <NUM> is first placed in the resected head h. The template <NUM> is advanced over the guide pin <NUM> into contact with the resected head. The size of the resected head h is determined from the template <NUM>. The guide <NUM> can be a reusable guide that is not specific to any particular patients. In other embodiments, the guide <NUM> is formed with reference to a specific patient. That is, the guide <NUM> can be formed to mate with the patient, such as by conforming in whole in part on a bone facing side to the shape of the bone as observed or measured using imaging or other devices prior to surgery.

<FIG> show that in some cases, a resection surface RX can be formed in a patient specific manner using a patient specific humeral cutting guide 600A. The humeral cutting guide 600A includes a first portion 602A, a second portion 604A, and a third portion 606A. One or more, e.g., all, of the first portion 602A, the second portion 604A, and the third portion 606A can be configured to contact specific parts of the humerus H. For example, each of these portions can have a substantial negative surface 608A. The surfaces 608A can be formed with reference to a pre-operative imaging of the patient's humerus, e.g., using CT scans, MRI, or X-ray information. The surfaces 608A can be configured such that the cutting guide 608A fits only in a specific location and orientation on the humerus H. The guide 600A also includes a cutting plane 610A. The cutting plane 610A is disposed at a specific location and orientation such that the resection Rx of the humerus H is at a pre-planned location and orientation. The resection Rx when formed using the cutting plane 610A will have a pre-planned peripheral shape. The pre-planned shape of the periphery of the resection Rx can be accounted for in forming portions of humeral assemblies and implants that engage the resection Rx. The guide 600A can have one or a plurality of apertures 612A to secure the guide 600A to the humerus H. The guide can have one or a plurality of apertures 614A that can be used to place guide pins or other members to facilitate one or more subsequent steps of preparing the humerus H or implanting components.

<FIG> shows that the resected surface of the head h can be prepared, such as by using a planar or a reamer <NUM>. The reamer <NUM> also can be guided by the guide pin <NUM>. The reamer <NUM> can be used to form a recessed surface S to which the assembly <NUM> will be applied after further preparation.

<FIG> shows a step of measuring depth of the recessed surface S. The purpose of this step is to provide a secondary confirmation that the assembly <NUM> will fit into the metaphysis without striking the lateral cortex. While the analysis of <FIG> indicates a diameter of base member <NUM> that could be used, the depth gauge <NUM> of <FIG> provides a depth sizing that confirms a maximum length, e.g., depth, that would fit in the recessed surface S surgeon is instructed to take the smaller of the two sizes determined.

<FIG> illustrates that following depth measurement, a bore B is formed in the surface S in initial preparation of the surface S to receive the shoulder assembly <NUM>. The bore B is formed using a drill <NUM>. The drill <NUM> can be a convention cannulated design configured to be advanced over the guide pin <NUM>. The drill <NUM> can be configured as a universal drill with a modular stop to obtain variable lengths. The drill <NUM> can be one of a plurality of drills, each drill of the plurality having a different size as appropriate. In certain methods, the process of forming the bore B and reaming the surface S as discussed above in connection with <FIG> can be combined. For example, a drill <NUM> can have a reaming feature disposed proximally of the bore forming features such that a continuous motion toward the surface formed using the guide <NUM> can initially form the bore B and subsequently form the surface S. Once the bore B is formed the humerus H may be prepared to receive the press-fit embodiments disclosed herein, e.g., in Figures <NUM>-<NUM>. <FIG> shows that once the bore B has been formed, the bore B can optionally be tapped to be prepared to receive the base member <NUM> of the shoulder assembly <NUM>. The tapping process can be achieved by using a helical tap component <NUM> that is advanced over the guide pin <NUM>. The helical tap <NUM> can follow the form of the helical structure <NUM> of the base member <NUM> such that the base member <NUM> can be easily advanced into the bore. The helical tap <NUM> can be secured to a shaft <NUM> that can be mounted to a motor driven drill or to a hand tool.

<FIG> shows that in some embodiments discussed herein a trunnion or other transverse extender can be coupled with the face F of the humerus H at the resection plane. The trunnion is illustrated by a dashed line labeled Tr. The trunnion can be applied after the bore B and/or the recessed surface S is or are formed and, optionally, after the tapping process. The trunnion can be applied by gentle pressure laterally against the face F or against the face F and the recessed surface S by hand or using a dedicated tool. The trunnion can be placed prior to inserting the base member <NUM> (or any of the other base members disclosed herein that can be mated to the trunnion).

<FIG> shows a step of inserting the base member <NUM>. The base member <NUM> is secured to a distal end of an inerter <NUM>. The inserter <NUM> has a stem <NUM> that is threaded at a distal end thereof. The threads of the stem <NUM> can be mated with the tool interface <NUM> (see <FIG>), e.g., with threads of the tool interface. Preferably the stem <NUM> is enlarged at a mid-section thereof providing at least a shoulder that can mate with the inner raised portion <NUM> of the base member <NUM>. A separate member <NUM> of the inserter <NUM> is advanced over the stem <NUM> to the tool interface <NUM>, and the force of advancing the base member <NUM> thus can be applied through the tool interface <NUM>, through the inner raised portion <NUM>, through the apertures <NUM> or through more than one of these (or other) features of the base member <NUM>. Splines <NUM> provide for good grip by the surgeon so that the surgeon can easily engage the stem <NUM> to the tool interface <NUM>. In another variation, a driver with a torqueing device at a proximal end couples at its distal end directly with the tool interface <NUM>, through the inner raised portion <NUM>, through the apertures <NUM> or through more than one of these (or other) features of the base member <NUM> to enable more direct transfer of torque to the base member. Preferably inserting the base member <NUM> into the bone includes placing the outer periphery <NUM> in the recessed surface S, e.g., at least partially recessed into the resected bone of the humerus H. The dashed line Tr shows the outer periphery of a trunnion that can optionally be placed between the face F and the base member <NUM> (or other base members described herein). The line Tr shows that the trunnion where provided cover all or substantially all of the face F between the base <NUM> and the perimeter RP of the humerus H.

<FIG> shows that after the base member <NUM> has been inserted, the locking device <NUM> can be inserted. The base member <NUM> is inserted by a rotation of the member by rotation of the inserter which is directly connected to the base member as discussed above in connection with <FIG>. The locking device <NUM> is inserted along the pathway by linear translation, e.g., by a movement along a generally straight axis without rotation. An inserter <NUM> is provided that has an enlarged head <NUM> that can be secured to or can just rest upon the proximal face of the annular member <NUM> of the proximal support <NUM>. The head <NUM> is then advanced over the splines <NUM> of the stem <NUM>, with the stem <NUM> acting as an axial guide. In order to implant the locking device <NUM> the first end <NUM> of the arm <NUM> or arms is aligned with the aperture <NUM> or apertures if more than one. The arms <NUM> are radially and circumferentially tapered and the apertures <NUM> are sized for the wider proximal end of the arms. This configuration helps guide the locking device <NUM> into the base member <NUM>. The proximal end <NUM> of the inserter <NUM> in configured for impacting the locking device <NUM> into the base member <NUM>. Once the locking device <NUM> is in place the base member <NUM> is fixed and will not back-out by subsequent rotation. The locking device <NUM> assures that the level of compression by the trunnion or by an enlarged flange, transverse plate or collar configured to reduce stress shielding initially provided by full advancement of the base <NUM> against the trunnion, flange, transverse plate or collar will be maintained such that stress shielding will be reduced, minimized, or eliminated.

<FIG> shows later steps of a method of implanting an anatomic shoulder prosthesis. After the base member <NUM> and the locking device <NUM> are placed, an anatomic articular component <NUM> can be coupled with the recess <NUM>. The anatomic articular component <NUM> comprises a convex surface <NUM>, analogous to the natural anatomy. The anatomic articular component <NUM> is placed with an impactor 684A. Although shown as a separate, dedicated device the insertion and impaction functions illustrated in <FIG> could be carried out by the same device. For example a contoured face to contact the surface <NUM> could have a portion configured for inserting the locking device <NUM> and/or the tray <NUM>. <FIG> shows an alternative step of a method of implanting a reverse shoulder prosthesis. After the base member <NUM> and the locking device <NUM> are placed, a reverse articular component <NUM> can be coupled with the recess <NUM>. In one form, the reverse articular component <NUM> includes a tray <NUM>. The tray <NUM> can be coupled with an articular component <NUM> comprising a concave surface for articulating with a glenoid sphere disposed on a glenoid of a scapula (discussed further below). The tray <NUM> is placed with an impactor 684A. The reverse shoulder prosthesis including the shoulder assembly <NUM>, the tray <NUM> and the articular component <NUM> is shown in <FIG>. A glenoid sphere <NUM> mated with a glenoid is shown in <FIG>. The shoulder joint provides movement of the patient's arm by articulating the component <NUM> over the glenoid sphere <NUM>.

As discussed above, a trunnion illustrated by the line Tr can be provided between the appropriate articular component placed in the steps illustrated in <FIG> to cover a portion of the resection Rx that is outlying relative to an outer periphery of the base <NUM> of the assembly <NUM>. The trunnion shown in dashed line Tr to indicate that the trunnion Tr is optional. The trunnion can be made patient specific in various ways discussed further herein. The trunnion can be placed in compression against the resection Rx and can cover some or all of the portion of the resection Rx subject to erosion arising from stress shielding. For example, the trunnion can be configured for the specific patient to extend medially and inferiorly to cover a reduce, minimize or eliminate stress shielding, e.g., of the medial calcar MC, as discussed above.

In one variation of these methods, assemblies, and kits the locking device <NUM> is inserted at the same time as some or all of the reverse articular component <NUM> or at the same time as the anatomic articular component <NUM>. The locking device <NUM> can be a separate component that is loaded onto an inserter or impacting tool that can be previously loaded with the reverse articular component <NUM> or the anatomic articular component <NUM>. The locking device <NUM> can be a separate component that is loaded onto an inserter or impactor with, but relatively moveable to, the reverse articular component <NUM> or the anatomic articular component <NUM>. The locking device <NUM> and the reverse articular component <NUM> can be formed as a monolithic structure that can be loaded together onto an inerter. The locking device <NUM> and the anatomic articular component <NUM> can be formed as a monolithic structure that can be loaded together onto an inerter.

The foregoing embodiments, whether generic or patient specific, can be applied to bones other than the humerus. For example, the concepts can be applied to a glenoid implant and to other joint applications.

<FIG> illustrate a shoulder assembly <NUM> that is adapted for securement to a glenoid. The shoulder assembly <NUM> is similar to the shoulder assembly <NUM> described above, except as described differently below. Any feature discussed above can be substituted in and supplement the features of the shoulder assembly <NUM>. The features of the shoulder assembly <NUM> can be substituted in and supplement the features of the shoulder assembly <NUM>.

<FIG> shows that the shoulder assembly <NUM> can be implanted into a glenoid region g of a scapula SC. The shoulder assembly <NUM> includes a base member <NUM> and a plate member <NUM>. The base member <NUM> has a medial end <NUM> and a lateral end <NUM>. <FIG>show that the base member <NUM> includes a body <NUM> that extends between the medial end <NUM> and the lateral end <NUM>. A lumen <NUM> extends in the body <NUM> from the lateral end <NUM> toward and in some cases entirely to the medial end <NUM>. A distal portion of the lumen <NUM> includes a threaded zone <NUM>, discussed below. The base member <NUM> includes a helical structure <NUM>, which is disposed along the body <NUM> between the medial and lateral ends <NUM>, <NUM>, respectively. The helical structure <NUM> extends from the medial end <NUM> to the lateral end <NUM> in some embodiments. In some embodiments a tool interface <NUM> is disposed lateral of a lateral end of the helical structure <NUM>.

The base member <NUM> includes a first pathway <NUM> accessible from the lateral end <NUM> of the base member <NUM>. The first pathway <NUM> is directed toward the medial end <NUM> through the helical structure <NUM>. The first pathway <NUM> can be located adjacent to an inner periphery of the helical structure <NUM>, as discussed above. The first pathway <NUM> can be partly defined by an outer surface of the body <NUM>. The first pathway <NUM> can be disposed generally transverse to the helical structure <NUM>. The first pathway <NUM> extends in a space <NUM> between successive portions of the helical structure <NUM>. In one embodiment, a first segment 830A of the first pathway <NUM> is disposed through a proximal portion of the helical structure <NUM>, a second segment 830B of the first path <NUM> is located medial of the first segment 830A, and a third segment 830C of the first path <NUM> is disposed medial of the second segment 830B. <FIG> shows the segments 830A, 830B, 830C of the path <NUM> in more detail.

<FIG> also shows that the base member <NUM> can include one or more barbs <NUM>. The barbs <NUM> are configured to facilitate softer material attachment. In some embodiment the internal portion of the base member <NUM> couples with a structure made of a soft material, such as polyethylene. One example of such an assembly is an anatomic configuration where a convex articular surface may be coupled with the scapula using the base member <NUM>. Another example is a reverse configuration with an inverse bearing surface (e.g. polyethylene glenoid sphere). The mode of connection between the base <NUM> and an articular or other component can include an interference fit between the barbs <NUM> and a projection of such component received in a space around which the barbs <NUM> are located, as described in connection with <FIG> and <FIG> of <CIT>. In other embodiments the barbs <NUM> can be replaced with mating threads, mating threads and fins and/or mating fins, as described in connection with <FIG> of <CIT>. In other embodiments, the barbs <NUM> can be replaced by a groove and a C-ring or other deflectable member that spans between the base member <NUM> and an articular or other component as described in connection with <FIG> and <FIG> of <CIT>.

The plate member <NUM> has a flange <NUM> and a first arm <NUM> that projects distally, medially away from or generally in a direction of implantation of the plate member <NUM> from the flange <NUM>. The plate member <NUM> can have a second arm <NUM> that projects away from the flange <NUM>. The first arm <NUM> is configured to be disposed in the first pathway <NUM> when the plate member <NUM> is disposed adjacent to the lateral end <NUM> of the base member <NUM>. The first arm <NUM> is disposed through bone in the space <NUM> between successive portions of the helical structure <NUM> when the shoulder assembly <NUM> is implanted.

The plate member <NUM> also includes a boss <NUM> that extends laterally of the flange <NUM>. The boss <NUM> comprises an arcuate outer periphery <NUM> and an aperture <NUM> that provides access to a lumen <NUM> through the aperture <NUM>. The lumen <NUM> is defined by a tapered surface <NUM> that mates with a glenoid sphere <NUM>, as discussed below. In another embodiment, the glenoid sphere <NUM> and the boss <NUM> are configured such that the glenoid sphere <NUM> coupled with the outer surface of the boss <NUM>.

The glenoid sphere <NUM> comprises a recess <NUM> disposed on a medial side and a convex side <NUM> disposed opposite the recess <NUM>. The glenoid sphere <NUM> has a tapered surface <NUM> disposed within the recess <NUM>. The tapered surface <NUM> is partly disposed in the recess <NUM> and partly extends medially of the recess <NUM>. The tapered surface <NUM> is disposed on a projection <NUM>. The boss <NUM> receives the projection of the glenoid sphere <NUM> therein. The tapered surface <NUM> on the boss <NUM> mates with the tapered surface <NUM> on the medial side of the glenoid sphere <NUM> to form a connection between the glenoid sphere <NUM> and the plate member <NUM>. The mating tapered surfaces <NUM>, <NUM> can form a Morse taper connection between the glenoid sphere <NUM> and the plate member <NUM>.

<FIG> illustrates further features of the shoulder assembly <NUM> that relate to connecting the components thereof together. The glenoid sphere <NUM> has a lateral opening <NUM> at the convex surface <NUM>. The opening <NUM> extends to a lumen <NUM> that extends from the opening <NUM> to a medial opening <NUM>. The lumen <NUM> includes a threaded zone <NUM> adjacent to the medial opening <NUM>. The threaded zone <NUM> can be used to couple the glenoid sphere <NUM> with an inserter. That is the threaded zone <NUM> can be threaded onto a corresponding threaded tip of the inserter. While threads are shown, other couplers can be used, such as a bayonet coupling in place of or along with the threaded zone <NUM>.

A fastener <NUM> is used to secure the glenoid sphere <NUM>, the plate member <NUM>, and the base member <NUM> together. The fastener <NUM> includes a medial end <NUM> with a threaded zone <NUM> and a lateral end <NUM>. The lateral end <NUM> includes a tool interface <NUM>.

The connection between the components of the shoulder assembly <NUM> is shown in <FIG>. The base member <NUM> can be advanced into the glenoid g following preparations similar to that discussed in connection with of <FIG>. Once so placed, the plate member <NUM> can be advanced into the base member <NUM>. The plate member <NUM> is advanced in a manner similar to the locking device <NUM>. The arms <NUM> are advanced into the helical structure <NUM>. Following placement of the plate member <NUM> into the base member <NUM>, the glenoid sphere <NUM> can be mated to the plate member. The projection <NUM> can be advanced into the lumen <NUM> (see <FIG>). Once the projection <NUM> is placed in the lumen <NUM> the fastener <NUM> can be advanced relative to the projection <NUM> and mated with the threaded zone <NUM>. Further advancing of the fastener <NUM> into the threaded zone <NUM> induces a friction fit, e.g., a Morse taper, at the tapered surfaces <NUM>, <NUM>. In one embodiment, the threaded zone <NUM> of the fastener <NUM> engages first the threaded zone <NUM> of the glenoid sphere <NUM> and then mates with the threaded zone <NUM>. In that embodiment, if the threaded zone <NUM> inadvertently disengage from the threaded zone <NUM> the back-out of the fastener <NUM> is limited such that the lateral end <NUM> of the fastener <NUM> does not protrude outside of the convex side <NUM> of the glenoid sphere <NUM>. For example, even if the threaded zone <NUM> is disengaged form the threaded zone <NUM>, lateral motion of the fastener <NUM> will be limited when a lateral end of the threaded zone <NUM> is disposed against a medial end of the threaded zone <NUM>. When in this position, in one embodiment the distance between the lateral end of the threaded zone <NUM> and the lateral end <NUM> of the fastener <NUM> will be less than the distance within the lumen <NUM> from the lateral end of the threaded zone <NUM> to the convex side <NUM> of the glenoid sphere <NUM>. Thus, the disengaged state of the fastener <NUM> will not result in the lateral end <NUM> protruding from the convex side <NUM>.

The plate member <NUM> includes additional features for enhancing securement to the bone. The plate member <NUM> can includes one or more apertures <NUM>. The apertures <NUM> can receive bone screws to enhance securement of the plate member <NUM> to the bone, e.g., to the scapula SC. Advantageously, the bone screw will lock into the apertures <NUM> by a thread engagement. In some embodiments, the locking mechanism will be multidirectional providing the possibility to lock the bone screws at a variable angle from the axis of the flange <NUM>. Additionally, the medial side of the plate member <NUM> can includes a textured surface <NUM> e.g., coated or layered with a porous material in order to accelerate tissue ingrowth such as bony ingrowth. Advantageously, the plate member <NUM> could be manufactured by additive manufacturing to incorporate the porous surface <NUM>.

Though shown in use to secure a hard material (e.g. ceramic, pyrocarbon, or metal) glenoid sphere <NUM> to a glenoid, the assembly <NUM> could be used to secure a soft-material (e.g. polyethylene, polyurethane, PEEK) glenoid sphere. Though shown in use to secure a glenoid sphere <NUM> to a glenoid, the assembly <NUM> could be used to secure an atomic glenoid. Though shown in use to secure a glenoid sphere <NUM> to a glenoid, the assembly <NUM> could be used in other anatomy to achieve very secure connection to relatively shallow layers of bone, which can include cancellous bone that is exposed during a procedure.

<FIG> show a number of other applications for the prosthesis assemblies described herein. In particular, the shoulder assemblies <NUM>, <NUM> can be applied to other bones and joints.

<FIG> shows that a proximal femur f can be fitted with a prosthesis assembly 100f similar to the prosthesis assembly <NUM>. The prosthesis assembly 100f is different from the shoulder assembly <NUM> in that it would be configured more particularly for the proximal femur.

<FIG> shows that a distal humerus h or to a distal radius r can be fitted with a prosthesis assembly <NUM>, r similar to the prosthesis assembly <NUM>. The prosthesis assembly <NUM>, r is different from the shoulder assembly <NUM> in that it would be configured more particularly for the distal humerus or radius.

<FIG> shows that a distal femur df and/or to a proximal tibia t can be fitted with a prosthesis assembly 100df, 100t similar to the prosthesis assembly <NUM>. The prosthesis assemblies 100df, t, are different from the shoulder assembly <NUM> in that they would be configured more particularly for the distal femur or proximal tibia. Also, on both side of the knee joint, implant sizing such as threads external diameter, core diameter, overall length could be sized according to patient anatomy per pre-operative planning based on CT-scan, MRI or any other medical images modality.

<FIG> shows that a distal tibia dt and/or to a proximal talus tal can be fitted with a prosthesis assembly 100dt, 100tal similar to the prosthesis assembly <NUM>. The prosthesis assemblies 100dt, tal, are different from the shoulder assembly <NUM> in that they would be configured more particularly for the distal tibia or proximal talus. Also, on both side of the ankle joint, implant sizing such as threads external diameter, core diameter, overall length could be sized according to patient anatomy per pre-operative planning based on CT-scan, MRI or any other medical images modality.

Each of the applications illustrated in <FIG> can employ the prosthesis assembly <NUM> with modifications similar to those discussed above in connection with the prosthesis assemblies <NUM>, 100r, 100f, and 100t.

<FIG> shows comparative performance of embodiments disclosed herein with respect to a stemless apparatus that does not have the helical structures disclosed herein nor the locking devices. The graph shows maximum tip out force which is measured by applying an off axis load at a known or prescribed fixed distance from a surface at or to which a shoulder assembly similar to the assembly <NUM> was implanted. The tip out force represents the resistance of the device to tipping out or becoming dislodge from the surface when subject to off axis loading. The forces were observed using a load cell or force transducer. As can be seen, the force of one embodiment is more than four times the force that would dislodge the conventional stemless component. This represents a significant improvement in the retention of the apparatuses disclosed herein compared to conventional stemless design which rely to a large extent on ingrowth for securement which can be sufficient some time after implantation but which can be subject to dislodgement prior to full integration by ingrowth.

As discussed above, a problem that can arise in orthopedic implant is stress shielding. This is a condition where stresses are prevented from being applied anywhere around a prosthetic implant, including at a resection surface. <FIG> illustrates a shoulder assembly 100B in which one or more components is made patient specific to reduce minimize or eliminate erosion due to stress shielding.

The shoulder assembly 100B includes an articular body <NUM> and a shoulder assembly <NUM>. The shoulder assembly <NUM> includes a base member 104D and the locking device <NUM>. The base member 104D is similar to any of the base members <NUM>, 104A, 104B, 104C except as described differently below. Because of the similarities, the description of the features that are consistent will not be repeated. As discussed above in connection with <FIG>, and <FIG>, the base member 104D can have at least a portion thereof adapted for a specific patient based upon pre-operative imaging. The locking device <NUM> also or alternatively can have at least a portion thereof adapted for a specific patient based upon pre-operative imaging. The shoulder assembly <NUM> includes a trunnion <NUM> that is configured to reduce, minimize or eliminate stress shielding.

<FIG> shows that the trunnion <NUM> can extend from a part of the base member 104D. <FIG> shows that the trunnion <NUM> can be coupled with the collar <NUM> of the base member 104D. The trunnion <NUM> can extend between the collar <NUM> and the perimeter RP of the humerus H at the face F. In one embodiment, the trunnion <NUM> includes an inner periphery <NUM> and an outer periphery <NUM>. The inner periphery <NUM> can be configured to mate with the collar <NUM> as discussed further below. The outer periphery <NUM> can be sized to match or nearly match the perimeter RP of the face F at the resection plane. The outer periphery <NUM> can be circular with a diameter that is tangential or nearly tangential to the portion of the perimeter RP that is closest to the center of the bore B to which the shoulder assembly <NUM> is mated.

<FIG> shows a shoulder assembly 950A that is similar to the shoulder assembly <NUM> except as described differently. <FIG> shows that the shoulder assembly 950A comprises a three component assembly. The one embodiment comprises a trunnion 954A that is the outermost component in the radial direction (e.g., transverse to the longitudinal axis LA). The base member 104D is located inward of the trunnion 954A. The locking device <NUM> is advanced into the base member 104D in the manner discussed above. The trunnion 954A has an outer periphery 956A that is adapted for a specific patient based upon pre-operative imaging. For example, as shown in <FIG> the outer periphery 956A can have a shape that matches the shape of the perimeter RP of the face F. The outer periphery 956A can be non-round. The outer periphery 956A can have can have one or more concavities or flat edges that face radially outwardly or away from the inner periphery <NUM>. The outer periphery 956A can have can have multiple convexities of different curvature to enable the outer periphery to extend further radially outward in certain regions than in other regions.

The size and or shape of the trunnion <NUM>, trunnion 954A can be such as to cover any or all portions of the face F that could be subject to erosion if exposed to stress shielding. The trunnion <NUM>, trunnion 954A can be configured to extend, for example toward or completely cover the medial calcar MC or other zone that could undergo erosion. The trunnion <NUM>, trunnion 954A can be moved into engagement with the face F and can even be caused to put initial or continuing pressure on the cancellous bone that is exposed following resection of the head of the humerus H. By making the trunnion <NUM> and the trunnion 954A patient specific, as discussed above, sufficient coverage of such regions without overhanging the perimeter RP of the face F can be achieved.

<FIG> show further structure of the trunnion <NUM> or the trunnion 954A. The trunnion <NUM> or trunnion 954A includes a wall <NUM> that projects in the direction of the longitudinal axis LA of the shoulder assembly <NUM> or shoulder assembly 950A. The wall <NUM> can surround a cylindrical space that can contain the collar <NUM> of the base member 104D. A first edge <NUM> can be aligned with an edge of the collar <NUM> that faces the first end <NUM>. In some embodiments, the radial projection <NUM> can be aligned to the first edge <NUM>. The radial projection <NUM> then act both as anti-rotation elements between the trunnion <NUM> and the base member 104E but also as an axial stop causing the position along the longitudinal axis LA of the base member 104E to the trunnion <NUM> to be controlled. A second edge <NUM> can be disposed opposite the first edge. The second edge <NUM> can be located along the longitudinal axis LA aligned with the inner raised portion <NUM> when the base member 104E is assembled to the trunnion <NUM> (see <FIG>). This configuration prevents the trunnion <NUM> from interfering with securing the articular component <NUM> to the humerus H. The trunnion <NUM> also includes a lateral flange portion <NUM> that extend radially away from the wall <NUM>. The flange potion <NUM> can extend radially by an amount that varies around the circumference, as discussed above such that the shape of the outer periphery <NUM> can be non-circular as needed to provide sufficient or full coverage of the face F of the humerus H at the resection. The flange portion <NUM> can define a third surface <NUM> that extends between the wall <NUM> and the outer periphery <NUM>. The third surface <NUM> can face the first surface <NUM> and can be configured to be placed in contact with the face F of the humerus H at the resection. The third surface <NUM> can be porous or otherwise configured to enhance ingrowth of the bone. The third surface <NUM> can be a porous surface.

<FIG> and <FIG> illustrate one way in which the trunnion <NUM> or the trunnion 954A and the base member 104D can be coupled together. The inner periphery <NUM> of the trunnion <NUM> can have a radial projection <NUM>. The radial projection <NUM> can extend radially inwardly of the inner periphery <NUM> toward the center of the trunnion <NUM>. The radial projection <NUM> can extend about one-half the radial extent of the collar <NUM>. The collar <NUM> can have a radial recess <NUM> that is configured to receive the radial projection <NUM>. The circumferential extent of the radial projection <NUM> preferably is a bit less than that of the radial recess <NUM>. The radial projection <NUM> can extend along a circumferential arc subtending about <NUM> degrees, about <NUM> degrees, about <NUM> degrees or up to about <NUM> degrees.

<FIG> supplements the method discussion above in <FIG>. <FIG> shows a portion of a method following resection of the humerus H. Thereafter the bore B and the recessed surface S can be formed. Thereafter the trunnion <NUM> can be advanced into the recessed surface S to contact the bone. This can be done by hand or by instrument. The trunnion <NUM> does not need to be impacted into the bone but can be in some techniques. Thereafter, the base member 104D can be advanced to the face F and into contact with the boundary between the recessed surface S and the bore B. The base member 104D can be further advanced until the helical structure(s) <NUM> engage the face F. Further rotation of the base member 104D pulls the base member 104D into the bone and eventually into contact with the trunnion <NUM>. Further rotation of the base member 104D relative to the trunnion <NUM> causes the base member 104D to rotate to a position where the radial projections <NUM> are nearly rotationally aligned with the radial recesses <NUM>. As the base member 104D further rotates the radial projection <NUM> become nested in the radial recess <NUM> as shown in <FIG>. At this point, the base member 104D applies a compression of the trunnion <NUM> against the bone surface between the recessed surface S and the perimeter RP. This compression not only reduces, minimizes or eliminates stress shielding but also creates positive compression of the bone in this area. As shown in <FIG> this can cause the medial calcar MC to be covered and even compressed by the trunnion <NUM>. In variations, the trunnion <NUM> and the trunnion 954A can have a roughened or porous surface or other configuration that encourages bone ingrowth to the surface from the face F.

In further variations, the connection between the trunnion and the base can be modified. For example, a trunnion 954B can be provided that comprises an annular projection 960A. The annular projection 960A can comprise a circular lip that extends a greater distance around the inner periphery <NUM> of the trunnion 954B. The annular projection 960A can extend entirely around the inner periphery <NUM> of the trunnion 954B. The trunnion 954B can be mated with a base member 104E that is similar to the base member 104D except as described differently. The base member 104D can, include an annular recess 964A. The annular recess 964A can extend around a peripheral portion of the base member 104E at a location between the first end <NUM> and the second end <NUM> thereof. The annular recess 964A can face the direction of the first end <NUM>. In one embodiment the annular recess 964A extends entirely around the periphery of the base member 104E. The base member 104E and the trunnion 954B are advantageous in that the base member 104E can be rotated into engagement with the trunnion 954B and such rotation can stop at any point providing sufficiently secure connection therebetween and/or sufficient loading of the face F at the resection plane. In the case of mating the radial projection <NUM> to the radial recess <NUM>, in some cases the surgeon will choose between whether to advance the base member 104D another one-third turn to move the radial projection <NUM> to the next radial recess <NUM>. This could cause more bone loading than desired. In further variations of the base member 104D and the trunnion <NUM> more or less than three radial projections <NUM> are mated with more or less than three radial recesses <NUM>. For example, there can be one, two, four, five, six, seven or eight radial projection <NUM> that mate with one, two, four, five, six, seven or eight radial recesses <NUM>.

As used herein, the relative terms "proximal" and "distal" shall be defined from the perspective of the humeral shoulder assembly. Thus, distal refers the direction of the end of the humeral shoulder assembly embedded in the humerus, while proximal refers to the direction of the end of the humeral shoulder assembly facing the glenoid cavity when the assembly is applied to the humerus. Distal refers the direction of the end of the humeral shoulder assembly embedded in the scapula, while proximal refers to the direction of the end of the humeral shoulder assembly facing the humerus when the assembly is applied to the glenoid. In the context of a glenoid component, the distal end is also sometimes referred to as a medial end and the proximal end is sometimes referred to as a lateral end.

The terms "approximately," "about," and "substantially" as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms "approximately", "about", and "substantially" may refer to an amount that is within less than <NUM>% of, within less than <NUM>% of, within less than <NUM>% of, within less than <NUM>% of, and within less than <NUM>% of the stated amount. As another example, in certain embodiments, the terms "generally parallel" and "substantially parallel" refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degree, <NUM> degree, or otherwise.

Some embodiments have been described in connection with the accompanying drawings. However, it should be understood that the figures are not drawn to scale. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, it will be recognized that any methods described herein may be practiced using any device suitable for performing the recited steps.

Claim 1:
A stemless humeral anchor (<NUM>), comprising:
a first end (<NUM>) configured to be embedded in a proximal portion of a humerus and a second end (<NUM>) opposite the first end;
a mating portion (<NUM>) comprising a central recess (<NUM>) extending from the second end toward the first end, wherein the central recess is configured to receive a corresponding mating portion of an articular component (<NUM>) of a humeral assembly;
a collar (<NUM>) disposed at the second end around the mating portion and extending generally transverse to a longitudinal axis of the recess; and
a plurality of rotation control features (<NUM>, 22A) disposed between the collar and the first end, wherein the rotation control features are configured to resist rotation of the stemless humeral anchor when the stemless humeral anchor is implanted; the stemless humeral anchor characterized in comprising
a void filling protrusion (<NUM>) disposed between the collar and the first end of the anchor,
wherein the void filling protrusion:
(<NUM>) is configured as a structure protruding and extending from one of the plurality of rotation control features toward a neighboring second one of the plurality of rotation control features, wherein the void filling protrusion is contiguous with said one of the plurality of rotation control features; or
(<NUM>) is configured as a radial protrusion from the mating portion and spaced apart from the rotation control features;
wherein at least a portion of the stemless humeral anchor is adapted for a specific patient based upon pre-operative imaging.