Glenoid Implant

Abstract

Various embodiments of novel glenoid implants for replacing a portion of the articular surface of a joint are disclosed that provide various enhancements to the glenoid implant, some examples of which are improved quality of primary fixation of the glenoid implant and improved revisability of the glenoid implant.

Description

[Technical field]

[0001] The present disclosure relates generally to glenoid implants for shoulder prostheses. [Background technology]

[0002] A shoulder prosthesis includes a glenoid implant intended to replace the glenoid cavity of the scapula and / or a humeral implant intended to replace the humeral head. The glenoid implant generally includes a glenoid body intended to articulate with the humeral head and fixation means for stabilizing the glenoid body relative to the scapula.

[0003] Optimal glenoid constraint may not be achieved with a simple spherical surface. This principle is highlighted by the natural glenoid / labrum combination, which is not spherical and does not provide the same maximum constraint in all translational directions. Referring to FIG. 1, currently available prosthetic shoulder glenoid components 10 have an articular surface 12 that is essentially defined by a spherical or double radius fully concave geometry. Thus, prior art glenoid components do not account for the different levels of constraint required for different activities, nor the changing curvature of the natural glenoid.

[0004] Additionally, currently available glenoid components have a fully concave articular surface, so that as the humeral head translates, the point of contact between the head and the glenoid cavity approaches the edge of the glenoid cavity. At some point, as illustrated in FIG. 2, the load vector 20 applied to the glenoid component 10 by the humeral head 22 no longer passes through the glenoid cavity 24, but loads it over the glenoid component 10, significantly increasing the tendency of the glenoid component 10 to loosen.

[0005] Typically, the glenoid prosthetic component is provided with one or more pegs or one or more keels on the side opposite the articular surface 12. The pegs or keels are inserted into mating holes provided in the glenoid cavity of the scapular neck. The pegs or keels are attached to the scapular neck using bone cement.

[0006] Many prior art glenoid components are of onlay design. Recently, studies have shown that inlay designs can improve glenoid component stability and reduce glenoid component loosening, which is common in total shoulder arthroplasty. With increasing interest in inlay designs for glenoid components, new and improved inlay and / or onlay glenoid components are needed. Summary of the Invention [Means for solving the problem]

[0007] Provided herein are various embodiments of glenoid implants that provide a replacement articular surface for the glenoid in the shoulder. Many of the disclosed glenoid implant embodiments are inlay style implants with various fixation features. The embedded inlay implant is placed within a reamed / drilled cavity in the glenoid such that the surface facing the articular surface is placed below the glenoid surface. Some of the glenoid designs shown may be used as inlay or onlay implants.

[0008] Various embodiments of the inventive hydrogel implants of the present disclosure will now be described in more detail in conjunction with the following drawing figures, in which structures are illustrated diagrammatically and are not intended to be drawn to scale. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a prior art glenoid component with a spherical articular surface and standard pegs. [Diagram 2] FIG. 1 is a side cross-sectional view illustrating overhang loads on a prior art glenoid component. [Diagram 3] FIG. 1 illustrates a glenoid cavity prepared with a ring-shaped trough into which a ring-shaped glenoid implant according to the present disclosure is received. [Figure 4]FIG. 1 illustrates a fully seated ring shaped glenoid implant of the present disclosure. [Diagram 5] FIG. 1 is a cross-sectional view of a fully seated ring-shaped glenoid implant. [Figure 6] FIG. 1 is a cross-sectional view of a ring-shaped glenoid implant mated with a prosthetic humeral head. [Figure 7] 13A-13D show an embodiment of a ring-shaped glenoid implant that includes pegs along the bottom surface of the implant. [Figure 8] 13A-13C show another embodiment of a ring-shaped glenoid implant configured for cementless fixation within the glenoid cavity. [Figure 9] This is a drill guide for identifying the center of the glenoid cavity. [Figure 10] FIG. 10 is a perspective view of the drill guide of FIG. 9 positioned on the glenoid cavity. [Figure 11] 13A-13D illustrate a procedure for cutting a trough in the glenoid cavity with a reamer. [Figure 12] 13A-13D illustrate a procedure for cutting a trough in the glenoid cavity with a reamer. [Figure 13] 13A-13D illustrate a procedure for cutting a trough in the glenoid cavity with a reamer. [Figure 14] FIG. 13 is a diagram of an example of a reamer for cutting a trough in the glenoid cavity. [Figure 15] 1 is a diagram of a drill guide according to an embodiment of the present disclosure; [Figure 16] FIG. 8 is a diagram of a glenoid cavity prepared with a trough and blind hole for receiving the ring-shaped glenoid implant of FIG. [Figure 17] FIG. 13 illustrates a glenoid implant according to another embodiment in an implanted state. [Figure 18] FIG. 18 is a side view of the glenoid implant of FIG. 17. [Figure 19] FIG. 19 is an isometric view of the anchor surface of the glenoid implant of FIGS. 17-18. [Figure 20] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 21] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 22] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 23] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 24] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 25] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 26] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 27] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 28] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 29] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 30] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 31] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 32] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Diagram 33] 20A to 20C are diagrams showing a procedure for preparing a glenoid cavity for the glenoid cavity implant of FIGS. 17 to 19. [Figure 34A] FIG. 13 is an isometric view of a glenoid implant according to another embodiment showing the articular surface of the implant. [Figure 34B] FIG. 34B is an isometric view of the glenoid implant of FIG. 34A showing the anchor surfaces of the implant. [Figure 35A]A series of diagrams showing the procedure for preparing the glenoid for the glenoid implant of FIGS. 34A - 34B. [Figure 35B] A series of diagrams showing the procedure for preparing the glenoid for the glenoid implant of FIGS. 34A - 34B. [Figure 36A] A series of diagrams showing the procedure for preparing the glenoid for the glenoid implant of FIGS. 34A - 34B. [Figure 36B] A series of diagrams showing the procedure for preparing the glenoid for the glenoid implant of FIGS. 34A - 34B. [Figure 37A] A diagram showing a glenoid implant according to another embodiment. [Figure 37B] A diagram showing a glenoid implant according to another embodiment. [Figure 37C] Cross - sectional views of the glenoid implant of FIGS. 37A - 37B. [Figure 37D] A diagram showing an example of the procedure for preparing the glenoid for receiving the glenoid implant of FIGS. 37A - 37B. [Figure 37E] A diagram showing an example of the procedure for preparing the glenoid for receiving the glenoid implant of FIGS. 37A - 37B. [Figure 37F] A diagram showing an example of the procedure for preparing the glenoid for receiving the glenoid implant of FIGS. 37A - 37B. [Figure 37G] A diagram showing the procedure for implanting the implant of FIGS. 37A - 37B. [Fig. 37H] A diagram showing the procedure for implanting the implant of FIGS. 37A - 37B. [Fig. 37I] A diagram showing the procedure for implanting the implant of FIGS. 37A - 37B. [Figure 38A] A diagram showing a glenoid implant according to another embodiment. [Figure 38B] A diagram showing a glenoid implant according to another embodiment. [Figure 38C] A diagram showing the procedure for implanting the implant of FIGS. 38A - 38B into the prepared glenoid. [Figure 38D]38A-38B into a prepared glenoid cavity. FIG. [Figure 38E] 38A-38B into a prepared glenoid cavity. FIG. [Figure 39A] FIG. 1 illustrates a glenoid implant according to another embodiment in its pre-implantation configuration. [Figure 39B] FIG. 1 illustrates a glenoid implant according to another embodiment in its pre-implantation configuration. [Figure 39C] FIG. 39C is a cross-sectional view of the glenoid implant of FIGS. 39A-39B. [Figure 39D] FIG. 39C illustrates the glenoid implant of FIGS. 39A-39B in its implanted configuration. [Figure 39E] FIG. 39C illustrates the glenoid implant of FIGS. 39A-39B in its implanted configuration. [Figure 39F] 39D-39E are cross-sectional views of the glenoid implant. [Figure 39G] 39A-39E illustrate a procedure for preparing a glenoid cavity to receive the glenoid implant of FIGS. 39D-39E. [Fig. 39H] 39A-39E illustrate a procedure for preparing a glenoid cavity to receive the glenoid implant of FIGS. 39D-39E. [Figure 39I] FIG. 39C is a cross-sectional view of the 2-in-1 reamer used in the procedure shown in FIGS. 39G-39H. [Figure 39J] 39G-39I depict a recess in the glenoid cavity formed by the procedure shown in FIGS. [Figure 39K] 39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Figure 39L] 39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Figure 39M] 39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Figure 39N] 39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Fig. 39O]39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Figure 39P] 39A-39B depict a procedure for implanting the glenoid implant of FIGS. 39A-39B. [Figure 40A] FIG. 1 illustrates a glenoid implant according to another embodiment. [Figure 40B] FIG. 1 illustrates a glenoid implant according to another embodiment. [Figure 40C] FIG. 1 illustrates a glenoid implant according to another embodiment. [Figure 40D] FIG. 40B is a view of a glenoid cavity prepared with a recess for receiving the glenoid implant of FIG. 40A. [Figure 40E] FIG. 40B is a diagram of the glenoid implant of FIG. 40A seated within the glenoid cavity. [Diagram 40F] FIG. 13 is an illustration of an all-polymer glenoid implant according to another embodiment. [Figure 40G] FIG. 13 is an illustration of an all-polymer glenoid implant according to another embodiment. [Figure 40H] 1 is a further embodiment of an all-polymer glenoid implant. [Fig. 40I] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40J] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40K] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40L] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40M] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40N] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40P] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40Q] 1 is a further embodiment of an all-polymer glenoid implant. [Figure 40R]FIG. 40H is a diagram of a glenoid cavity prepared with a recess for receiving the glenoid implant of FIG. 40J. [Figure 40S] FIG. 40J is a view of the glenoid implant of FIG. 40J seated within the glenoid cavity. [Figure 40T] FIG. 40I shows the glenoid implant of FIG. 40I seated within the glenoid cavity. [Fig. 40U] FIG. 2 is a diagram of a portion of a recess provided in the glenoid for receiving one of the all-polymer glenoid implants, the portion being configured to form an interference fit with the all-polymer glenoid implant. [Figure 41A] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Figure 41B] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Figure 41C] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Figure 41D] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Figure 41E] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Fig.41F] 11A-11D are various embodiments of another glenoid implant according to the present disclosure; [Figure 41G] FIG. 41C is a detailed view showing the interference fit between the glenoid and the glenoid implant shown in FIGS. 41A-41F. [Figure 42A] FIG. 1 illustrates an embodiment of a metal-lined glenoid implant. [Figure 42B] FIG. 1 illustrates an embodiment of a metal-lined glenoid implant. [Figure 42C] FIG. 1 illustrates an embodiment of a metal-lined glenoid implant. [Fig.42D] FIG. 1 illustrates an embodiment of a metal-lined glenoid implant. [Figure 42E] FIG. 42C is a diagram of a metal anchor component of the metal-lined glenoid implant of FIGS. 42A-42D. [Fig.42F]FIG. 42C is a diagram of a metal anchor component of the metal-lined glenoid implant of FIGS. 42A-42D. [Fig.42G] FIG. 42C is a view of a glenoid cavity prepared with a recess for receiving the metal-lined glenoid implant of FIGS. 42A-42C. [Fig. 42H] FIG. 42C is a view of a glenoid cavity prepared with a recess for receiving the metal-lined glenoid implant of FIGS. 42A-42C. [Figure 43A] FIG. 13 illustrates a porous metal lined glenoid implant embodiment. [Figure 43B] FIG. 13 illustrates a porous metal lined glenoid implant embodiment. [Figure 43C] FIG. 43C is an exploded view of the porous metal-lined glenoid implant of FIGS. 43A-43B. [Fig. 43D] FIG. 43C is a cross-sectional view of the porous metal-lined glenoid implant of FIGS. 43A-43B. [Figure 43E] FIG. 43E is a detailed view of area A shown in FIG. 43D. [Figure 43F] 43A-3B, looking straight on at the articular surface 1130 of the implant. [Figure 43G] 43A-43B show how various modular non-circumferential fixation features can be used in combination with the metal-backed glenoid implant of FIGS. 43A-43B. [Fig. 43H] 14 is a cross-sectional view of an implant converted to an inverted configuration, where a tapered cylindrical feature is assembled with a glenosphere. Additionally, there can be screw holes through the cylindrical attachment. [Figure 44A] FIG. 13 is an isometric view of a glenoid implant using a circular bone-engaging rim in accordance with another embodiment. [Figure 44B] FIG. 44B is a side view of the glenoid implant of FIG. 44A. [Figure 44C] FIG. 44B is a cross-sectional view of the glenoid implant of FIG. 44A. [Fig.44D]FIG. 13 is an isometric view of a glenoid implant using a circular bone-engaging rim in accordance with another embodiment. [Figure 44E] 44B is a cross-sectional view of a variation of the glenoid implant of FIG. 44A. [Fig.44F] 44B is a cross-sectional view of a variation of the glenoid implant of FIG. 44A. [Figure 45A] FIG. 13 is an isometric view of a glenoid implant using a circular bone-engaging rim in accordance with another embodiment. [Figure 45B] FIG. 45B is a side view of the glenoid implant of FIG. 45A. [Figure 45C] FIG. 13 is an isometric view of a glenoid implant using a circular bone-engaging rim in accordance with another embodiment. [Figure 45D] FIG. 45D is a side view of the glenoid implant of FIG. 45C. [Figure 45E] FIG. 45B shows how the glenoid cavity can be prepared with a recess for receiving the glenoid implant shown in FIGS. 44A and 45A. [Fig.45F] FIG. 44A shows the glenoid implant of FIG. 45A implanted within the glenoid cavity. [Figure 45G] FIG. 45B illustrates an example of a cutting tool for preparing a glenoid cavity to receive the glenoid implant shown in FIGS. 44A and 45A. [Fig. 45H] FIG. 45B illustrates an example of a cutting tool for preparing a glenoid cavity to receive the glenoid implant shown in FIGS. 44A and 45A. [Figure 46A] FIG. 13 is an isometric view of a glenoid implant using a circular bone-engaging rim in accordance with another embodiment. [Figure 46B] FIG. 46B is a cross-sectional view of the glenoid implant of FIG. 46A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] This description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered part of the entire written description. The drawing figures are not necessarily to scale, and certain features may be exaggerated to a certain extent or in some schematic manner for clarity and conciseness. In the description, relative terms such as "horizontal", "vertical", "up", "down", "top" and "bottom" and their derivatives (e.g., "horizontally", "downward", "upwardly", etc.) should be interpreted as referring to the directions being described at the time and as shown in the drawing figures in the description. These relative terms are for convenience of description and are not usually intended to require a particular orientation. Terms including "inward" vs. "outward", "longitudinal" vs. "lateral", etc. should be interpreted relative to each other or relative to an axis of extension or center of rotation or axis of rotation, as appropriate. Terms relating to attachment, coupling, and the like, such as "connected" and "interconnected", refer to a relationship in which structures are fixed or attached to each other directly or indirectly through intervening structures, as well as both movable and fixed attachments or relationships, unless otherwise specified. Although only a single device is illustrated, the term "device" should also be construed to include any collection of devices that individually or jointly execute a set (or sets) of instructions to perform any one or more of the methods described herein. The term "operably connected" is an attachment, coupling, or connection that enables the associated structures to operate in the manner intended by that relationship. In the claims, when a means-plus-function clause is used, it is intended to cover the structures described, suggested, or revealed by the written description or drawings to perform the described function, including equivalent structures as well as structural equivalents.

[0011] Provided herein are various improved glenoid implants having an articular surface configured to mate with an anatomical humeral head or humeral component of a shoulder replacement implant system, and thus, references to "humeral head" as used herein should be construed to include both the anatomical humeral head as well as the implant humeral head.

[0012] According to the embodiment illustrated in Figures 3-7, an inlay glenoid implant 100 is provided having a ring-like structure. The ring-shaped glenoid implant 100 has a ring-shaped body 101 including a hole 102. The ring-shaped body 101 includes an articular surface 110 on one side and a base surface 101a on the opposite side. The hole 102 extends completely through the implant 100 from the articular surface 110 to the base surface 101a. When implanted within the glenoid cavity 24, the articular surface 110 faces outward from the glenoid cavity 24 to replace the natural articular surface of the glenoid cavity. The articular surface 110 is configured to mate with the humeral head.

[0013] The ring shape of this glenoid implant allows for shoulder stabilization while minimizing bone reaming / removal, which may be beneficial for surgical site healing. The ring shape with a hole in the center allows the glenoid to support the curvature of various mating components while maintaining a continuous ring of contact. This differs from traditional articular surfaces that have a theoretical single point contact (which does not account for material deformation). Additionally, this nature of the ring contact provides a self-centering force on the mating spherical head of the humerus. Self-centering is desirable to help keep the humeral head from moving away from the glenoid.

[0014] The hole 102 can be of any desired shape and any size. For example, in some embodiments, the hole 102 can have a circular outline as shown. In some other embodiments, the hole can be configured to have a polygonal outline. The polygon can be a regular polygon or an irregular polygon. In some embodiments, the hole 102 can be configured as a patient-specific irregular shaped hole customized to match the shape of the area of ​​the patient's glenoid that is desired to remain intact such that the ring-shaped implant 100 surrounds the preserved area.

[0015] The curvature of the articular surface 110 can be configured to have any desired contour, in some embodiments, the curvature of the articular surface 110 can be spherical.

[0016] With reference to Figure 3, the glenoid cavity 24 is prepared with a ring-shaped recess 24a in which the ring-shaped glenoid implant 100 is placed. Figure 4 shows the ring-shaped glenoid implant 100 seated in the ring-shaped recess 24a. Figure 5 shows a cross-sectional view of the seated ring-shaped glenoid implant 100. The bottom surface 101a of the ring-shaped body 101 is in contact with the bottom surface of the ring-shaped recess 24a. The cross-sectional view of Figure 6 shows the humeral head 22 mating with the articular surface 110 of the ring-shaped glenoid implant 100.

[0017] The corresponding surfaces of the ring-shaped body 101 and the ring-shaped recess 24a are configured to provide a tight fit so that the glenoid implant 100 can be securely seated in the recess 24a. The base surface 101a of the ring-shaped body 101 and the bottom surface of the ring-shaped trough 24a are contoured to match each other's contours to ensure that the two surfaces are in intimate contact when the glenoid implant 100 is inserted into the ring-shaped recess 24a. In the illustrated example, the base surface 101a and the bottom of the ring-shaped recess 24a are flat. However, in some embodiments, the base surface 101a can be concave, convex, or flat, and the bottom surface of the ring-shaped trough 24a has a complementary contour. Similarly, the inner surface 105 and the outer surface 103 of the ring-shaped glenoid implant 100 are substantially orthogonal to the base surface 101a. The ring-shaped recess 24a includes an inner surface 24a2 and an outer surface 24a1 that are substantially orthogonal to the bottom surface of the recess 24a. (See FIG. 5). When the glenoid implant 100 is inserted into the ring-shaped recess 24a for implantation, corresponding surfaces of the glenoid implant 100 and the ring-shaped recess 24a contact each other to hold the glenoid implant 100 securely in place.

[0018] In some embodiments, the ring-shaped glenoid implant 100 may be made entirely or partially, particularly the portion that forms the articular surface 110, from a synthetic material, such as, for example, polyethylene (e.g., ultra-high molecular weight polyethylene (UHMWPE)), polyetheretherketone (PEEK), etc. All references herein to UHMWPE include all variants of UHMWPE in orthopedic applications, such as vitamin E-diffused UHMWPE. In a preferred embodiment, the ring-shaped glenoid implant 100 may be made entirely or partially, particularly the portion that forms the articular surface 110, from a hydrogel material.

[0019] Hydrogel materials, as referred to herein, refer to three-dimensional solids resulting from cross-linked hydrophilic polymer chains formed with polyvinyl alcohol (PVA). In addition to PVA, hydrogel materials can include one or more other materials, such as, for example, other hydrogels, other polymeric materials, additives, etc. In some embodiments, the PVA content of the hydrogel in the implants disclosed herein can be about 40% by weight. The PVA content of the hydrogel can range from about 10% by weight to about 80% by weight, depending on the particular application.

[0020] Hydrogels can include water, saline, other liquids, combinations thereof, and the like. In some embodiments, under certain circumstances, saline may be preferred over water, as saline may help maintain osmotic balance with the surrounding anatomical tissues after implantation. The exact composition of the hydrogel components in the implant can be selected for optimal performance in a particular application to achieve the desired or required strength, load-bearing capacity, compressibility, flexibility, longevity, durability, resiliency, coefficient of friction, and / or other properties and characteristics.

[0021] In some embodiments, such hydrogel portion(s) of the ring-shaped glenoid implant 100 and all other embodiments of the glenoid implants disclosed herein can be formulated for drug delivery and / or seeded with growth factors and / or cells. In such embodiments, the hydrogel components can include one or more of the following: chondrocytes, growth factors, bone morphogenetic proteins, collagen, hyaluronic acid, nucleic acids, and stem cells. Such factors and / or any other materials included in the implant can help to promote and / or facilitate long-term fixation of the implant in the joint site.

[0022] The ring-shaped glenoid implant can be installed in the prepared glenoid cavity 24 using a variety of methods. Figure 7 shows an embodiment of a ring-shaped glenoid implant 100 that can include one or more pegs 120 along a base surface 101a for securing the implant in the glenoid cavity 24. Each of the pegs 120 can include one or more slots 122 for receiving bone cement for securing the implant 100 in the bone 24. To use this embodiment of the ring-shaped glenoid implant, the glenoid cavity 24 must be prepared with corresponding holes for the pegs 120. The bone preparation procedure is described below.

[0023] 8 shows another embodiment of a ring-shaped glenoid implant 100 configured for cementless fixation within the glenoid cavity 24. In this embodiment, the glenoid implant 100 includes at least a portion of an outer surface 103 coated with a porous trabecular metal material 104, such as ADVANCE® BIOFOAM™ from Wright Medial Technology, Inc., for bone ingrowth into the glenoid implant. The structure of the coated trabecular metal material resembles that of trabecular bone. In some embodiments, at least a portion(s) of the inner surface 105 of the ring-shaped glenoid implant 100 may also be coated with trabecular metal material.

[0024] In some embodiments of the ring-shaped glenoid implant 100 configured for cementless fixation, a majority of the ring-shaped glenoid implant 100, including the bone-engaging base surface 101a, may be formed of a porous trabecular metal material, and the articular surface portion may be formed of a hydrogel bonded to the porous trabecular material.

[0025] With reference to Figures 9-17, a corresponding procedure for preparing the glenoid 24 for receiving the ring-shaped glenoid implant 100 is disclosed. Shown in Figure 9 is a drill guide 200 positioned on the glenoid 24 for identifying the center of the glenoid 24. The drill guide 200 includes a guide hole 201 and a plurality of arms 202a, 202b, 202c, and 202d extending radially from the guide hole 201 perpendicular to the central axis of the guide hole 201. Each of the arms 202a-202d is provided with an edge guide 205 at the end of the arm. As can be seen from the perspective view of Figure 10, each of the edge guides 205 extends perpendicular to the respective arm and is configured for use across the periphery of the glenoid 24 as shown. As shown in Figure 9, in a preferred embodiment of the drill guide 200, two of the arms 202a and 202c extend from the guide hole 201 180° apart from each other. The remaining two arms 202b and 202d are disposed astride arm 202c. All of the arms extend from guide hole 201 perpendicular to the central axis of guide hole 201, so that the arms are in the same plane.

[0026] The positioning of the arms and their edge guides 205 allows the edge guides 205 to fit around the periphery of the glenoid 24 as shown so that the guide holes 201 automatically locate the geometric center. To accommodate different sized glenoids among patients, the drill guide 200 can be provided in a variety of graduated sizes.

[0027] After an appropriately sized drill guide 200 is placed over the glenoid fossa 24 as shown in Figure 9, a hole is drilled into the glenoid fossa 24 via the guide hole 201. A pin P is then inserted into the drilled hole as shown in Figure 10. With reference to Figures 11 and 13, once the pin P is in place, the drill guide 200 is removed and a reamer 220 is used to carve a ring-shaped trough 24a into the glenoid fossa 24.

[0028] Placement of the drill guide 200 on the glenoid fossa 24 can be accomplished visually or with the use of Wright Medical Technology's Blueprint™ 3D surgical planning system. Additionally, the drill guide 200 can be a patient-specific instrument manufactured with the Blueprint™ system.

[0029] As shown in Figures 13 and 14, the reamer 220 is generally shaped like a bell saw and includes a mandrel portion 223 and a cylindrical blade portion 222. The cylindrical blade portion 222 has a cutting end 222c with a width 222w that forms a trough 24a. The cylindrical blade portion 222 has an outer wall 222a and an inner wall 222b. Two circumferential edges defined by the cutting end 222c and the outer and inner walls 222a, 222b form a cutting edge. The outer and inner walls 222a, 222b may further include a groove 222g that aids in the cutting action and the release of bone chips during the reaming procedure. The shape and dimensions of the groove 222g may be altered to optimize the reaming efficiency of the reamer 220. A hole 221 is provided in the center of the mandrel portion 223 so that the reamer 220 can be positioned over the pin P. Mandrel portion 223 includes a drive tool mating portion 225. Drive tool mating portion 225 is configured to mate with a drive tool, such as a hand surgical drill, capable of rotating reamer 220 for the reaming operation.

[0030] If the glenoid implant 100 is the embodiment shown in Figure 7 having a plurality of pegs 120 for securing the implant within the glenoid cavity 24, a drill guide 240 shown in Figure 15 can be used to prepare blind holes in the bottom of the trough 24a to receive the pegs 120. The drill guide 240 is configured to slide over the pins P such that the drill guide 240 aligns with the trough 24a. Figure 16 is an illustration of the glenoid cavity 24 prepared with the trough 24a and blind holes 24h to receive the glenoid implant 100 embodiment shown in Figure 7.

[0031] 17-21, an embodiment of a glenoid implant 300 configured to be implanted in a glenoid cavity in an inlay configuration is disclosed. FIG. 17 shows the glenoid implant 300 implanted in the glenoid cavity 24. FIG. 18 is a side view of an embodiment of the glenoid implant 300. FIG. 19 is an isometric view of the glenoid implant 300. The glenoid implant 300 includes a body 310 including an articular surface 330 and an opposing anchor surface 322. The glenoid implant 300 can be configured to have a shape that maximizes the articular surface of the glenoid cavity 24 replaced by the glenoid implant 300. The articular surface 330 is contoured to replicate the anatomical articular surface of the glenoid cavity 24. In some embodiments, the anchor surface 322 includes one or more fixation features, such as struts, finned anchors, or keels extending therefrom. In the illustrated example, three anchors 325 extend from the anchor surface 322.

[0032] 17, the size and shape of the glenoid implant 300 is set to be implanted into a prepared glenoid 24 with a recess for receiving the glenoid implant 300. Inlay glenoid implants, such as the glenoid implant 300 and the ring glenoid implant 100, are smaller than the entire surface of the glenoid 24. Thus, the inlay configuration allows only the defective or damaged portion of the glenoid articular surface to be replaced, minimizing disturbance of the natural glenoid bone material.

[0033] In some embodiments, each of the one or more anchors 325 may include one or more bone cement pockets 327. Bone cement may be used to enhance fixation of the glenoid implant 300 when the implant is secured within a corresponding recess provided within the glenoid cavity 24. Each of the pockets 327 in the anchors 325 may retain a quantity of bone cement to aid in fixation of the glenoid implant 300.

[0034] In some embodiments, the glenoid implant 300 may be formed in whole or in part, particularly the portion that forms the articular surface 110, from a synthetic material, such as, for example, polyethylene (e.g., ultra-high molecular weight polyethylene (UHMWPE)), polyetheretherketone (PEEK), etc. In a preferred embodiment, the articular surface 330 may be formed from a hydrogel material as previously described.

[0035] In some embodiments, the glenoid implant 300 can be formed of a suitable surgical grade metal or metal alloy. Some examples are cobalt chromium alloys and titanium alloys. If the glenoid implant 300 is formed of a metal or metal alloy, the body 310 of the implant can be thinner due to the additional stiffness and strength provided by the metal. In metal embodiments of the glenoid implant 300, the anchor surface 322 can be coated with a porous trabecular metal coating as described above to promote bone tissue ingrowth after the implant 300 is implanted. In some embodiments, a portion of the sidewall 310s (see FIG. 18) of the implant 300 can also be coated with a porous trabecular metal coating.

[0036] 20-31, a corresponding procedure for preparing the glenoid 24 to receive the glenoid implant 300 is disclosed. First, the drill guide 30 is placed on the glenoid 24 to identify locations for drilling two blind holes for the guide pins. Placement of the drill guide 30 on the glenoid 24 can be accomplished visually or with Wright Medical Technology's Blueprint™ 3D surgical planning system. In some embodiments, the drill guide 30 can be a patient-specific instrument manufactured with the Blueprint™ 3D surgical planning system.

[0037] The drill guide 30 includes a main body 31 with two drill guide holes 37a, 37b. The main body 31 includes a number of arms 32 extending outwardly from the main body 31. The arms 32 terminate in edge guides 35 at the ends of the arms 32. Each of the edge guides 35 extends perpendicular to the respective arms and is configured to be used to span the periphery of the glenoid 24, as illustrated in Figures 20 and 21. The drill guide 30 can be provided in a variety of sizes to accommodate different sized glenoids in different patients. When the appropriately sized drill guide 30 is placed on the glenoid 24, the two drill guide holes 37 are positioned at the desired location. Once the drill guide 30 is positioned at the desired location, two blind holes are drilled into the glenoid 24 using the guide holes 37. Two guide pins P1, P2 are then placed into the drilled blind holes in the glenoid 24 and the drill guide 30 is removed. See Figures 22-23.

[0038] A series of bone reaming steps are then performed to form an appropriately shaped recess in the glenoid 24 to receive the glenoid implant 300. Referring to FIG. 24, a spade drill S guided by pins P1, P2 is used to form two wide, shallow blind holes (e.g., recesses). FIG. 25 shows the first shallow blind hole 24b thus formed. In the illustrated example, guide pin P1 was used first to form the first blind hole 24b, but the other guide pin P2 could have been used first. This procedure is repeated on guide pin P2 to form a second shallow blind hole 24c as shown in FIG. 26. The two shallow blind holes 24b and 24c overlap as shown to form a single shallow recess 24d. The depth of the shallow blind hole is determined to correspond to the thickness of the glenoid implant 300.

[0039] 27-29, a cookie cutter type bone cutting device 39 is applied to create the final contour for the shallow recess 24d to receive the glenoid implant 300. The cutting edge 39c of the bone cutting device 39 is shaped to cut the bone between the two shallow blind holes 24b, 24c along the dotted line C shown in FIG. 28. As a result, excess bone material between the two shallow blind holes 24b, 24c is removed to form a recess 24d in the glenoid fossa 24 having the contour of the glenoid implant 300, as shown in FIG. 30. To help guide and align the cookie cutter type bone cutting device 39, the bone cutting device can be provided with two guide holes 39a and 39b appropriately sized and positioned on the bone cutting device 39 to slide over the pins P1, P2. Once the bone cutting device 39 is in place and the cutting edge 39c is in contact with the intended cut line C, the bone cutting device 39 can be tapped to cut into the bone.

[0040] Referring to Fig. 30, the bone cutting device 39 may further include an additional drill guide hole 39e that may be used to drill a blind hole for receiving an anchor 325 that may be provided on the glenoid implant 300. Fig. 32 is a cross-sectional view of an implanted glenoid implant 300. Fig. 33 shows an example of a humeral head implant H1 interacting with the articular surface of the glenoid implant 300.

[0041] 34A-34B, an embodiment of a glenoid implant 400 configured to be implanted in the glenoid cavity in another inlay configuration is disclosed. Similar to the glenoid implant 300, the implant 400 can be configured with a shape that maximizes the articular surface area of ​​the glenoid cavity 24 replaced by the implant 400. FIG. 34A shows an isometric view of the top (i.e., articular surface 430 side) of the glenoid implant 400. FIG. 34B shows an isometric view of the glenoid implant 400 from the bottom. The glenoid implant 400 includes a body 410 having an articular surface 430 and an opposing anchor surface 422. The articular surface 430 is contoured to mimic the natural articular surface of the glenoid cavity 24. The articular surface 430 includes a concave profile that is intended to anatomically cooperate with the humeral head, whether natural or artificial. The anchoring surface 422 may be coated with a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which may promote bone tissue ingrowth to enhance attachment of the glenoid implant 400 to the glenoid cavity after the implant is implanted into the prepared glenoid cavity.

[0042] An anchoring keel 425 extends from the anchor surface 422. The anchoring keel 425 is configured to securely fix the implant 400 in an inlay configuration within the glenoid 24 to minimize or prevent rocking of the implant 400 after it is implanted. The keel 425 extends along a longitudinal axis XX. The keel 425 preferably includes a longitudinal dimension or length that is greater than its transverse dimension or width. The keel 425 may have the structure of an elongated ridge or upstanding structure attached to the body 410 of the glenoid implant 400 with a length oriented along the longitudinal axis of the glenoid implant 400. The length of the keel 425 along the longitudinal axis XX may be greater, lesser, or the same as the body 410 of the glenoid implant 400. The keel 425 may have a generally planar side that may include various projections, recesses, anchoring members, and holes.

[0043] 34B, the keel 425 includes a transverse hole 427 to allow for the formation of a cement bridge to secure the implant 400 if it is to be cemented. If the glenoid implant 400 is not to be cemented, the hole 427 may allow for the formation of a bone bridge. In some embodiments, the hole 427 may be used to receive one or more fasteners, such as bone screws.

[0044] The process of preparing the glenoid 24 to receive the glenoid implant 400 will now be described in connection with Figures 35A-36B. The process involves removing a portion of the glenoid 24 from the articular surface of the glenoid 24 using a milling guide 40 to form a shallow recess capable of receiving the implant 400. The milling guide 40 has a ring-like structure with an opening 42 in the center. With reference to Figure 36A, after the milling guide 40 is placed in a desired location on the glenoid 24, the opening 42 allows access to an area of ​​the glenoid 24 for removal using a reamer bit 55. As shown in the legend to Figure 36A, an optional example path for the milling operation using the reamer bit can be as indicated by the arrows shown within the opening 42. The direction of movement for the reamer bit can be in any direction as long as the reamer is maintained within the opening 42. If any bone material remains at the site after the reamer bit is used, particularly in the center of the opening 42, the bone material can be removed using a rongeur drill bit to complete the bone preparation.

[0045] 36B, the milling operation results in a shallow recess 24f formed in the glenoid 24 that is shaped to receive the glenoid implant 400. A slot 24g for the keel can be formed using a punch tool.

[0046] The shape of the opening 42 can be any desired shape. It can be circular, oval, pear-shaped, etc. The back side of the milling guide 40 that contacts the glenoid can be flat for universal use for all patients, or the surface can be preformed with a customized surface with a patient-specific contour. The milling guide 40 also includes a number of holes 43 on the ring-like structure for receiving fixation pins / tacks 50 for temporarily attaching the milling guide 40 in place during the subsequent reaming procedure. In the illustrated example, the milling guide 40 has three such holes 43. The pin 50 includes a shoulder 52 in the center of its length with a larger diameter than the hole 43, so that the milling guide 40 cannot slide up the pin 50 after the pin 50 is placed in place as shown in FIG. 35B.

[0047] 37A-37C, another embodiment of a glenoid implant 500 is disclosed. The glenoid implant 500 is configured to be securely press-fit into a recess provided in the glenoid cavity to replace a damaged natural articular surface. The glenoid implant 500 includes a circular body 510 having an articular surface 530 on one side and an anchoring surface 520 on the opposite side, and an annular sidewall 511 extending along the periphery of the circular body 510. The articular surface 530 is contoured with a generally concave surface that mimics the natural articular surface of the glenoid cavity. The articular surface 530 is configured to anatomically cooperate with the humeral head.

[0048] The articular surface 530 has a surface finish suitable for an articular surface intended to mate with the humeral head. The anchoring surface 520 is generally flat and is intended to contact the cortical bone of a prepared glenoid. The anchoring surface 520 may be coated with a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which may promote bone tissue ingrowth to enhance attachment of the glenoid implant 500 to the glenoid after the implant is press-fit into a prepared recess in the glenoid.

[0049] To allow for the press-fit function of the glenoid implant 500, the annular side wall 511 includes a plurality of retention legs 512 disposed along the annular side wall 511. The glenoid implant 500. In some embodiments, the retention legs 512 are extensions of the annular side wall 511 that are folded back toward the articular surface 530 such that each of the retention legs 512 is formed as a U-shaped leaf spring as shown in the cross-sectional view of FIG. 37C. Each of the U-shaped leaf spring shapes of the retention legs 512 is in an open configuration and is elastically compressible in a radially inward direction. The U-shape is open toward the articular surface 530 side of the implant 500. To press-fit the implant 500 into the shallow recess 24h (see FIG. 37G) formed in the glenoid, the recess must have a diameter slightly smaller than the outer diameter of the glenoid implant 500 defined by the outer surface of the retention legs 512. Thus, when the glenoid implant 500 is inserted into the shallow annular recess formed in the glenoid cavity, the retention legs 512 are elastically compressed by the side walls of the circular recess as the implant 500 is forced in. The outward spring force exerted by the retention legs 512 against the side walls of the annular recess 24h securely holds the implant 500 in the recess. The retention legs 512 are compressed into the bone improving anchoring quality. Due to the U-shaped configuration of the retention legs 512 opening towards the surface of the glenoid cavity 24, the more the implant 500 is pulled outward from the recess, the more the retention legs 512 spread radially outward into the surrounding bone to securely hold the implant 500 in its implanted position.

[0050] The glenoid implant 500 may be formed of a metal, such as titanium, CoCr alloy, or a high modulus polymer, such as UHMW polyethylene. Preferably, the glenoid implant 500 is integrally formed as a single piece construction. Preferably, but not required, the retention legs 512 and circular body 510 are formed from a single material. The thickness and diameter of the glenoid implant 500 may be selected to be any desired value for the conditions at the surgical site.

[0051] In the examples shown in Figures 37A-37C, the glenoid implant 500 has a generally circular or disc-like profile. However, the glenoid implant 500 is not limited to such a circular shape and can be provided with any desired non-circular profile. For example, the glenoid implant 500 can have a glenoid-like profile similar to the implant 300 shown in Figure 18 and the implant 400 shown in Figure 34A.

[0052] 37D-37F are diagrams illustrating an example of a procedure for preparing a glenoid cavity to receive the glenoid implant of FIGS. 37A-37B. Referring to FIG. 37D, a pin P4 is placed in a desired location within the glenoid cavity 24. A suitable pin guide instrument or Wright Medical Technology's Blueprint™ 3D surgical planning system may be used to place the pin P4 in the desired location. Referring to FIG. 37E, a cannulated 2-in-1 reamer 60 is then slid over the pin P4 to form a circular recess in the glenoid cavity 24 including a circular substantially flat surface 24k surrounded by a circumferential annular recess 24h, as shown in detail in FIG. 37F. The circular flat surface 24k is formed to accommodate an anchoring surface 520 of the implant 500 when the implant is press-fitted into the recess. The annular recess 24h receives the retaining legs 512 of the implant 500. The reamer 60 includes an annular cutting ring 64 having a disk-shaped body 63 with a circular flat surface on the bone-facing side. Also, the circular flat surface on the bone-facing side of the cutting ring 64 is an abrasive surface for cutting the glenoid cavity. Referring to Fig. 37G, after the circular recess is formed, the pin P4 is removed and the glenoid implant 500 is press-fit into the recess. Fig. 37H shows the implant 500 fully seated. Fig. 37I is a cross-sectional view of the glenoid implant 500 fully seated.

[0053] 38A-38B, a press-fit glenoid implant 600 according to another embodiment is provided. The glenoid implant 600 is configured to be tightly press-fitted into a recess prepared in the glenoid cavity to replace a damaged natural articular surface. The glenoid implant 600 includes a circular body 610 including an articular surface 630 on one side and a base surface 620 on the opposite side, and an annular sidewall 611 extending along the circumference of the circular body 610. The annular sidewall 611 is a grooved surface including a plurality of grooves with a blade 612 formed between two adjacent grooves. The glenoid implant 600 is intended to be press-fitted into a circular recess prepared in the glenoid cavity 24. Similar to the circular recess shown in FIGS. 37F-37G for the glenoid implant 500, the circular recess prepared for the glenoid implant 600 also includes a circular flat surface 24k surrounded by an annular recess 24h that accommodates the contour of the base surface 620 of the press-fit glenoid implant 600. This can be seen in the cross-sectional view of Figure 38E of the press-fit glenoid implant 600 fully seated within the circular recess. The blades 612 interfere with the surrounding bone to achieve a secure press-fit.

[0054] The articular surface 630 is contoured with a generally concave surface that mimics the natural articular surface of the glenoid cavity. The articular surface 630 is configured to anatomically cooperate with the humeral head, whether natural or artificial.

[0055] The articular surface 630 has a surface finish suitable for an articular surface intended to mate with a natural or prosthetic humeral head. The anchoring surface 620 is generally flat and is intended to contact the cortical bone of a prepared glenoid. The anchoring surface 620 may be coated with a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which may promote bone tissue ingrowth to enhance attachment of the glenoid implant 600 to the glenoid after the implant is press-fit into a prepared recess in the glenoid.

[0056] The procedure for preparing the glenoid cavity 24 for implantation of the press-fit implant 600 therein is similar to the procedure illustrated in Figures 37D-F above. This procedure is used to form a circular recess including a circular flat surface 24k surrounded by an annular recess 24h. The implant 600 is then press-fit into the circular recess. A view of the fully seated glenoid implant 600 is shown in cross section in Figures 38D and 38E.

[0057] The glenoid implant 600 may be formed of a metal such as titanium, a CoCr alloy, or PEEK. Preferably, the glenoid implant 600 is integrally formed as a single piece construction. The thickness and diameter of the glenoid implant 600 may be selected to any desired value for the conditions at the surgical site.

[0058] 39A-39F illustrate a glenoid implant 700 according to another embodiment of the present disclosure. The glenoid implant 700 includes a circular body 710 including an articular surface 730 on one side and an anchoring surface 720 on the opposite side, and a plurality of flexible legs 712 extending from the periphery of the circular body 710 in a direction away from the articular surface 730. Thus, the overall shape of the glenoid implant 700 generally resembles a bottle cap.

[0059] The glenoid implant 700 can be transformed from its pre-implantation configuration to its implanted configuration by plastic deformation. Figures 39A-39C show the glenoid implant 700 in its pre-implantation configuration, and Figures 39D-39F show the glenoid implant 700 in its implanted configuration.

[0060] In the pre-implantation configuration, the circular body 710 has a shallow dome-like configuration such that the articular surface 730 is convex and the opposing anchoring surface 720 is concave, as shown in FIGS. 39A-39C. Preferably, the flexible legs 712 extend from the periphery of the circular body 710 substantially parallel to or toward the longitudinal axis L of the implant 700. The longitudinal axis L is defined through the center of the circular body 710. Substantially parallel here means parallel or nearly parallel. This configuration can be seen in the cross-sectional view of FIG. 39C. The flexible legs 712 can be maintained substantially parallel to the longitudinal axis L to allow the implant 700 to be inserted into the recessed glenoid fossa 24.

[0061] In the implanted configuration, the implant's circular body 710 has been plastically deformed so that it is now curved in the opposite direction to its pre-implanted configuration. Here, the articular surface 730 is concave and the opposing anchoring surface 720 is convex, as shown in FIGS. 39D-39F. In this implanted configuration, due to the direction of curvature of the circular body 710, the circumferential flexible legs 712 now extend radially outward (i.e., away from the longitudinal axis L). This configuration helps to secure the glenoid implant 700 within a recess provided in the glenoid cavity 24, as will be further described below.

[0062] With reference to the diagrams of Figures 39G-39L, the procedure for preparing the glenoid cavity 24 and implanting the glenoid implant 700 will now be described. First, a recess is formed in the glenoid cavity 24 to receive the glenoid implant 700 using the procedure illustrated in Figures 39G, 37D-37F. With reference to Figure 39G, the pin P4 is placed in the desired location in the glenoid cavity 24. Using an appropriate pin guide instrument or Wright Medical Technology's Blueprint™ 3D surgical planning system, the pin P4 can be placed in the desired location based on where the glenoid implant 700 needs to be centered. Next, with reference to Figure 39H, a cannulated 2-in-1 reamer 70 is slid over the pin P4 to create a circular recess for receiving the glenoid implant 700. The reamer 70 includes an annular cutting ring 74 with a disk-shaped body having a circular abrasive surface 73 on the bone-facing side. The circular abrasive surface 73 is not flat, but has a curvature as shown in the detailed cross-sectional view of Figure 39I. This curved surface 73 is convex toward the bone surface being abraded. The 2-in-1 reamer 70 thus forms a recess in the glenoid 24 that includes a circular concave surface 24k surrounded by a circumferential annular recess 24h, as shown in detail in FIG. 39J. The circular concave surface 24k is configured to receive the anchoring surface 720 of the implant 700 when it is in the implanted configuration.

[0063] 39K and 39L, after forming an appropriately sized recess in the glenoid cavity 24, the glenoid implant 700 in a pre-implantation configuration is inserted into the recess 24h. The flexible legs 712 of the implant 700 are received within the annular recess 24h. As shown, the articular surface 730 is convex. The flexible legs 712 extend substantially parallel to or toward the longitudinal axis L of the implant 700 so as to not interfere when inserted into the recess 24h. FIG. 39M shows a cross-sectional view of the glenoid implant 700 after it has been inserted into the recess.

[0064] Next, referring to FIG. 39N, an impactor 80 is used to press down on the articular surface 730 to plastically deform the implant 700 into its embedded configuration. The impactor 80 includes a convex tip 82 having a curvature that substantially matches the convex curvature of the articular surface 730 after the implant 700 has been deformed into its embedded configuration. FIGS. 39O and 39P show the implant 700 after it has been deformed into its embedded configuration. Here, the implant body 710 is deformed into the embedded configuration such that the articular surface 730 is concave. Here, the opposing anchoring surface 720 of the implant 700 is convex and in contact with the concave circular concave surface 24k of the recess in the glenoid cavity 24.

[0065] In the implanted configuration of the glenoid implant 700, the articular surface 730 is contoured with a generally concave surface that mimics the natural articular surface of the glenoid cavity. The articular surface 730 is configured to anatomically cooperate with the humeral head, whether natural or artificial.

[0066] The articular surface 730 has a surface finish suitable for an articular surface intended to mate with a natural or prosthetic humeral head. The anchoring surface 720 is generally flat and is intended to contact the cortical bone of a prepared glenoid. The anchoring surface 720 and / or the flexible legs 712 may be coated with a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which may promote bone tissue ingrowth to enhance attachment of the glenoid implant 700 to the glenoid after the implant is press-fit and implanted.

[0067] The implant 700 may be formed of a metal such as CoCr, Nitinol, or Titanium. Preferably, the glenoid implant 700 is integrally formed as a single piece construction. Preferably, but not required, the retention legs 712 and the circular body 710 are formed from a single material. The thickness and diameter of the glenoid implant 700 may be selected to any desired value for the conditions at the surgical site. Due to the high modulus of elasticity of the material forming the implant 700, when the implant is being transformed from the pre-implanted configuration to the implanted configuration, the transition occurs immediately when the force 730 exerted by the impactor 80 on the convex anchoring surface reaches a threshold level and the body 710 of the implant pops from the pre-implanted configuration to the implanted configuration.

[0068] As previously mentioned, when the implant 700 is in its embedded configuration shown in Figures 39D-39F, the flexible legs 712 splay outwardly. Thus, as shown in cross-section in Figure 39P, when the implant 700 is converted to its embedded configuration while seated within a recess in the glenoid fossa 24, the legs 712 splay outwardly and abut against the outer wall of the annular recess 24h, thereby securing the implant within the recess. Long-term fixation of the implant 700 within the glenoid fossa 24 is further enhanced by a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which may be coated on the legs 712 and / or the anchoring surface 720.

[0069] 40A-41F, embodiments of inlay glenoid implants configured for improved fixation in the glenoid are disclosed that are integrally formed of a high modulus polymeric material such as UHMWPE or PEEK. These implants are referred to herein as "all-polymer" implants. All-polymer glenoid implants can include one or more peripheral fixation features located around the periphery (or circumference) of the implant body or even extending beyond the periphery of the implant body. Such placement of fixation features improves the stability of the implant, particularly the lateral stability, and the quality of fixation.

[0070] In some embodiments, the one or more peripheral fixation features can be a tapered outer wall profile that allows for an interference fit along the perimeter of the implant body. In other embodiments, the one or more peripheral fixation features can be one or more anchoring elements extending from the bottom or base surface of the implant body, such as posts, pegs, finned anchors, etc., that are positioned beyond the perimeter of the implant body. These fixation features can mate with the glenoid cavity by a mechanical interference fit, a partial interference fit, no interference fit, or any combination thereof. These fixation features can also be reinforced with bone cement. Bone cement reinforced fixation features can be provided with or without a cement pocket.

[0071] Additionally, all-polymer glenoid implants may further include conventional anchoring elements extending from the base surface of the implant body, such as, for example, posts, pegs, finned anchors, keels, etc., in addition to the peripheral fixation features.

[0072] The outer contour of the all-polymer glenoid implant can be tapered (i.e., frustoconical), straight (i.e., perpendicular to the base surface (the surface opposite the articular surface) and the base surface is flat), or can have an edge that causes interference with the bone. The bone cavity prepared to receive the glenoid implant can have an undercut created by an instrument that mates with the interference edge.

[0073] According to some embodiments, the all-polymer glenoid implant may also include one or more through holes to allow for the use of a bone screw(s) for further fixation where appropriate.

[0074] According to some embodiments, the base surface of the all-polymer glenoid implant can be flat, concave, or convex. 40A-40C show an embodiment of an all-polymer glenoid implant 800 configured to be implanted within the glenoid in an inlay configuration. The glenoid implant 800 includes a substantially circular, disc-shaped body 805 having an articular surface 830, an opposing anchoring base surface 820, and a sidewall 810 extending between the two. The glenoid implant 800 may be configured to have a shape that maximizes the articular surface of the glenoid fossa 24 that is replaced by the glenoid implant 800. The articular surface 830 is contoured to replicate the natural articular surface of the glenoid fossa 24.

[0075] Because of its peripheral fixation feature, the sidewall 810 preferably has a tapered profile that allows for an interference fit along the periphery of the implant body when the implant 800 is embedded in a recess provided in the glenoid cavity 24. The taper of the sidewall 810 is such that the articular surface 830 is larger in diameter than the anchoring base surface 820. Thus, the body 805 has a shallow frusto-conical shape. The interference fit provided by the tapered sidewall 810 is a fixation feature that extends radially outward beyond the periphery of the substantially circular body 805.

[0076] The glenoid implant 800 includes additional features that help secure the implant 800 within the glenoid cavity 24. For example, at least one finned anchor 825 and a number of stabilizing posts 825' extend from the anchor surface 820. The articular surface 830 is generally concave and configured to mate with the humeral head.

[0077] The fin anchors 825 and stabilizing posts 825' of the glenoid implant 800 extend from the base surface 820 to secure the glenoid component 800 to the glenoid 24. The stabilizing posts 825' are disposed radially outward from the fin anchors 825 such that the stabilizing posts 825' are disposed along the peripheral region of the glenoid implant 800 to provide stability to the glenoid implant 800 after implantation. In the illustrated embodiment, the fin anchors 825 and stabilizing posts 825' extend substantially perpendicularly from the base surface 820. In some embodiments, the fin anchors 825 can extend at various other angles relative to the base surface 820. The fin anchors 825 are preferably disposed substantially centrally on the base surface 820 and are in the form of a cylindrical shaft having a proximal end 825p and a distal end 825d. (See FIG. 40C). Finned anchor 825 is attached to base surface 820 at proximal end 825p and is tapered at distal end 825d to facilitate insertion of finned anchor 825 into an anchor receiving hole prepared in glenoid fossa 24. In one embodiment, distal end 825d of finned anchor 825 includes a conical tip or other shape to facilitate insertion into glenoid fossa 24, with or without a pre-drilled hole. In the example shown in FIGS. 40A-40C, distal end 825d has a conical tip.

[0078] In the illustrated example, finned anchor 825 includes a substantially constant diameter and further includes a plurality of radially outwardly extending fins 827. Each of fins 827 is spaced apart from one another along the length of finned anchor 825. Fins 827 may be evenly spaced apart or the spacing may vary as desired.

[0079] The fins 827 are flexible and configured to curve or deform when a force is applied to them. The deformation of the fins 827 can be plastic or elastic. In some embodiments, the fins 827 are formulated to deform plastically upon insertion into the glenoid fossa 24 and assume a generally curved configuration once implanted. In some embodiments, the fins 827 are formulated to deform elastically upon insertion into the glenoid fossa 24 and once implanted, constantly exert an amount of force against the surrounding bone as the fins attempt to return to their undeformed configuration.

[0080] In some embodiments, the finned anchor 825 and its fins 827 can be integrally formed with the body 805. For example, the glenoid implant 800 can be molded as a single unitary structure or machined from a monolithic piece of polymeric material. In other embodiments, the finned anchor 825 and the body 805 are separate components. In an alternative embodiment, the body 805 can be molded from a first material, while the finned anchor 825 and its fins 827 are molded from a second material. In this embodiment, the second material is preferably stiffer than the first material.

[0081] The stabilization posts 825' prevent the glenoid implant 800 from moving relative to the glenoid fossa 24 once the implant 800 is implanted within the glenoid fossa 24. The stabilization posts 825' preferably extend substantially perpendicular to the base surface 820 of the implant 800. Each of the stabilization posts 825' includes a body having a proximal end 825p' and a distal end 825d'. Each of the stabilization posts 825' is attached at its proximal end 825p' to the base surface 820 of the implant body 805. The stabilization posts 825' may also include a recess or a series of recesses that receive and secure bone cement to maintain the stabilization posts 825' in place.

[0082] The stabilization post 825' is preferably shorter than the finned anchor 825. Similar to the distal end 825d of the finned anchor 825, the distal end 825'd of the stabilization post 825' may also be tapered to facilitate insertion of the stabilization post 825' into a prepared hole in the glenoid fossa 24. In some embodiments, the distal end 825'd of the stabilization post 825' has a conical tip or other shape that facilitates insertion into the glenoid fossa 24, with or without a pre-drilled hole.

[0083] The stabilization struts 825' may be arranged in any configuration on the base surface 820. In one embodiment, the stabilization struts 825' are arranged such that one of the stabilization struts 825' is located further from the finned anchor 825 than the other stabilization struts 825'. In another embodiment, the stabilization struts 825' are arranged around the finned anchor 825 along a periphery substantially equidistant from the finned anchor 825 and each adjacent stabilization strut 825'.

[0084] The structure and function of finned anchor 825 is similar to that of a similar anchor described in U.S. Patent No. 10,524,922, the disclosure of which is incorporated herein by reference.

[0085] 40D-40E, a recess 24A of a size and shape suitable for receiving the glenoid implant 800 is reamed into the glenoid cavity 24. The recess includes a bottom surface 24B in which a hole 24C is drilled to receive an anchor 825 and a further hole 24D is drilled to receive a stabilizing post 825'. The holes 24C and 24D have a diameter and depth suitable for receiving a corresponding finned anchor 825 or stabilizing post 825'. The recess 24A has a sidewall 24E that is tapered to match the taper of the sidewall 810 of the glenoid implant 800. FIG. 40E shows the glenoid implant 800 seated within the recess 24A.

[0086] In some embodiments, each of the stabilization posts 825' may include one or more bone cement pockets 828. Bone cement may be used to enhance fixation of the glenoid implant 800 when the implant is secured within a corresponding recess 24A provided in the glenoid fossa 24. Each of the pockets 828 may hold a quantity of bone cement.

[0087] 40F-40G show an all-polymer glenoid implant 900 configured for inlay implantation within the glenoid cavity according to another embodiment. The glenoid implant 900 includes a body 905 including an articular surface 930, an opposing base surface 920, and a sidewall 910 extending between the two. The glenoid implant 900 can be configured to have a shape that maximizes the articular surface of the glenoid cavity 24 that is replaced by the glenoid implant 900. The articular surface 930 is contoured to replicate the natural articular surface of the glenoid cavity 24.

[0088] The sidewall 910 can have a tapered profile that allows for an interference fit along the periphery of the implant body when the implant 900 is implanted into a recess prepared in the glenoid fossa 24. The taper of the sidewall 910 is such that the articular surface 930 is larger in diameter than the base surface 920.

[0089] In this embodiment, the body 905 has a plurality of protrusions 905' that extend radially outward beyond the substantially circular periphery (or circumference) of the body 905, and a fixation feature, such as a stabilization post 925', is provided on each of the protrusions 905' that extend from the base surface. Because the protrusions 905' allow fixation features to be positioned outwardly around the body 905, this configuration helps to increase the lateral stability of the glenoid implant 900 within the bone and reduce implant rocking.

[0090] The glenoid implant 900 may further include one or more additional non-peripheral fixation features that aid in securing the implant 900 within the glenoid 24. The non-peripheral fixation features may include any one of a post, a finned anchor, or a keel, etc. For example, in the illustrated glenoid implant 900, an anchor surface 920 has a finned anchor 925 extending therefrom. An articular surface 930 is generally concave and configured to mate with the humeral head.

[0091] The finned anchors 925 and stabilizing posts 925' of the glenoid implant 900 extend from the base surface 920 to secure the glenoid component 900 to the glenoid 24. The stabilizing posts 925' are positioned radially outward from the finned anchors 925 such that the stabilizing posts 925' are positioned along the peripheral region of the glenoid implant 900 to provide stability to the glenoid implant 900 after implantation.

[0092] In the illustrated embodiment, the finned anchor 925 and the stabilizing struts 925' extend substantially perpendicularly from the base surface 920. In some embodiments, the finned anchor 925 can extend at various other angles relative to the base surface 920. The finned anchor 925 is preferably substantially centered on the base surface 920 and is in the form of a cylindrical shaft having a proximal end 925p and a distal end 925d. (See FIG. 40G). The finned anchor 925 is attached to the base surface 920 at the proximal end 925p and is tapered at the distal end 925d to facilitate insertion of the finned anchor 925 into an anchor receiving hole prepared in the glenoid fossa 24. In one embodiment, the distal end 925d of the finned anchor 925 includes a conical tip or other shape that facilitates insertion into the glenoid fossa 24, with or without a pre-drilled hole. In the example shown in FIGS. 40F-40G, the distal end 925d has a conical tip.

[0093] In the illustrated example, the finned anchor 925 includes a substantially constant diameter and further includes a number of radially outwardly extending fins 927. Each of the fins 927 are spaced apart from one another along the length of the finned anchor 925. The fins 927 can be evenly spaced apart or the spacing can vary as desired.

[0094] The fins 927 are flexible and configured to curve or deform when a force is applied to them. The deformation of the fins 927 can be plastic or elastic. In some embodiments, the fins 927 are formulated to deform plastically upon insertion into the glenoid 24 and assume a generally curved configuration once implanted. In some embodiments, the fins 927 are formulated to deform elastically upon insertion into the glenoid 24 and once implanted, constantly exerting an amount of force against the surrounding bone as the fins attempt to return to their undeformed configuration.

[0095] In some embodiments, the finned anchor 925 and its fins 927 can be integrally formed with the body 905. For example, the glenoid implant 900 can be molded as a single unitary structure or machined from a monolithic piece of polymeric material. In other embodiments, the finned anchor 925 and the body 905 are separate components. In an alternative embodiment, the body 905 can be molded from a first material, while the finned anchor 925 and its fins 927 are molded from a second material. In this embodiment, the second material is preferably stiffer than the first material.

[0096] The function of the finned anchors 925 and stabilizing posts 925' are similar to that of the finned anchors 825 and stabilizing posts 825' of the glenoid implant 800, except that the stabilizing posts 925' are positioned beyond the periphery of the substantially circular body 905 to further enhance the lateral stability of the implant 900 when implanted within the glenoid fossa 24.

[0097] In some embodiments, each of the stabilization posts 925' may include one or more bone cement pockets 928. Bone cement may be used to enhance fixation of the glenoid implant 900 when the implant is secured within a corresponding recess provided in the glenoid 24. Each of the pockets 928 may hold a quantity of bone cement.

[0098] In some embodiments, the glenoid implant 900 can be provided in various configurations to have different types and numbers of fixation elements. For example, the implant 900 can have only one type of fixation element extending from the anchoring surface 920 (i.e., finned anchors 925, stabilization posts 925', keel 929, etc.) as one or more fixation elements provided. In other embodiments, the implant 900 can have different bone cement pockets or even different types of anchoring elements such as keels. For example, FIG. 40H illustrates an all-polymer glenoid implant embodiment 900a in which the stabilization posts 925' have one or more bone cement pockets 928' that are slots cut into the stabilization posts 925'. FIG. 40I illustrates an all-polymer glenoid implant embodiment 900b that includes two stabilization posts 925' that are positioned 180 degrees apart from one another. Also, the cement pockets 928 on the stabilization posts 925' are grooves. FIG. 40J shows an all-polymer glenoid implant embodiment 900c with the same three stabilizing posts 925' as in the embodiment of FIG. 40H, but without any finned anchors 925. In the all-polymer glenoid implant embodiment 900c, the base surface 920 can be substantially flat, or can have a slight convex or concave contour. The advantage of a convex contoured base surface 920 may be that less subchondral (good) bone reaming is required, as such a surface is more compatible with the articulation of the natural glenoid. The convex surface also provides a larger contact area than a flat base surface. The advantage of a concave contoured base surface 920 is that it may improve the stability of the implant by reversing the "soap dish" effect that can cause lateral slippage of the implant under circumferential loading conditions. Additionally, the concave back surface allows the periphery of the implant to be placed deeper into the bone, while retaining the cortical bone thickness in the center, where the forces are greatest and where the primary non-peripheral fixation features are located.

[0099] FIG. 40K illustrates an all-polymer glenoid implant embodiment 900d having a keel 929 rather than finned anchors 925 or stabilizing struts 925'. The keel 929 and variations thereof are similar to the keel for the glenoid component described in U.S. Patent No. 8,080,063, the contents of which are incorporated herein by reference. In some embodiments, the glenoid implant 900 may be configured with any combination of fixation features described herein as desired.

[0100] 40L illustrates an all-polymer glenoid implant embodiment 900e in which the base surface 920 of the implant can be contoured in any of a variety of ways to accommodate the conditions of the glenoid 24. In the illustrated example, the base surface 920 is sloped on one side of the implant to form a wedge-shaped profile for the body 905 of the implant 900.

[0101] 40M and 40N show an all-polymer glenoid implant embodiment 900f including a plurality of protrusions 905' with mini fin anchors 925" extending from a base surface 920 as one or more peripheral fixation features. The glenoid implant 900f further includes a protruding lip 960 along the periphery of the base surface 920 side of the body 905 as an additional peripheral fixation feature. The protruding lip 960 mates with a side wall 24K of a recess provided in the glenoid cavity 24 (see recess 24G in FIG. 40M) to create an interference fit that helps secure the implant 900f within the glenoid cavity 24.

[0102] This shape is intended to control the translational motion of the mating humeral head, only allowing it to translate across the surface in one linear vector. For example, a "sweep" geometry orientation allows the glenoid to easily traverse the glenoid surface along an up-down trajectory, but resists traversing the glenoid in an anterior-posterior motion.

[0103] FIG. 40P is a side view of an all-polymer glenoid implant embodiment 900g including a tapered side wall 910 and multiple protrusions 905′ with mini fin anchors 925″ extending from a base surface 920 as one or more peripheral fixation features. This glenoid implant 900g does not have any non-peripheral fixation features.

[0104] 40Q illustrates an all-polymer glenoid implant embodiment 900h in which multiple screw holes 970 are peripheral fixation features and do not have any additional non-peripheral fixation features such as posts, finned anchors, or keels. The glenoid implant 900h is fixed to the glenoid using bone screws. In some other embodiments, the glenoid implant can have other fixation features in addition to the screw holes.

[0105] Figure 40R is an illustration of a glenoid 24 that has been reamed to form a recess 24G of an appropriate size and shape to receive the example glenoid implant 900 shown in Figure 40J. The recess 24G includes a bottom surface 24H, a sidewall 24K, and a bore 24J that is drilled along the periphery of the recess 24G to receive a stabilization post 925' and to accommodate and mate with a protrusion 905' that extends radially outward beyond the substantially circular periphery of the implant body 905.

[0106] Figure 40S is a view of the implant 900 of Figure 40J embedded within recess 24G. Figure 40T is a view of the implant 900 of Figure 40I embedded within a recess that is similar to recess 24G in shape and size to the implant 900 of Figure 40I.

[0107] As can be seen in Figures 40F-40K, in some embodiments of the glenoid implant 900, the transition region 911 between the projection 905' and the remainder of the sidewall 910 portion is a curved surface. The contours of the recess 24G and hole 24J formed in the glenoid 24 are shaped to form an interference fit with the curved transition region 911 of the glenoid implant 900. This is illustrated in Figure 40U. Figure 40U shows a portion of the glenoid 24 around one of the holes 24J provided in the glenoid 24. Where the sidewall 24K of the recess 24G meets the hole 24J is the cusp 24X. This cusp 24X overlaps with the curved transition region 911 of the glenoid implant 900 to form an interference fit. In Figure 40U, the contour of the transition region 911 of the glenoid implant 900 is shown overlapping the cusp 24X to allow for an interference fit.

[0108] 41A-41C show another embodiment of an all-polymer glenoid implant 900j. The glenoid implant 900j includes as its peripheral fixation feature a locking rim structure 940 that secures the implant 900j in a recess 24 prepared in the glenoid cavity by forcing the implant body 905 into the recess. The glenoid implant 900j further includes a finned anchor 925 as one or more additional fixation features. As better seen in the side view of FIG. 41C, the locking rim 940 is defined by an annular groove 942 formed in the outer wall 910 of the substantially circular body 905 and an undercut groove 944 formed in the base surface 920 of the body 905. The locking rim 940 is of a larger diameter than the substantially circular body 905 and includes an edge 941 that projects radially outward from the body 905. The fit between the locking rim 940 and the recess 24 prepared in the glenoid cavity can be seen in detail in FIG. 41G. FIG. 41G is a partial cross-sectional view of an all-polymer glenoid implant 900j embedded in a prepared recess 24 in the glenoid cavity. The cross-section shows the structure of the locking rim 940. An annular groove 942 and an undercut groove 944 define the locking rim 940. An edge 941 of the locking rim 940 projects radially outward beyond the sidewall 910. The recess reamed in the glenoid cavity is similar to the recess 24A shown in FIG. 40D and has a sidewall 24E and a bottom surface 24B. To receive the glenoid implant 900j, the bottom of the recess's sidewall 24E is further reamed radially outward with an undercut, thus forming an overhang 24E'. Because the edge 941 of the locking rim 940 projects radially outward, the diameter of the rim 940 is larger than the diameter of the recess defined by the sidewall 24E. Thus, as the glenoid implant 900j is pressed into a recess in the glenoid cavity 24 in the direction indicated by arrow A, the locking rim 940 resiliently bends radially inward until edge 941 clears overhang 24E'. Once edge 941 clears overhang 24E', the locking rim 940 springs outward to the configuration shown in FIGURE 41G, where edge 941 and overhang 24E' create a mechanical lock that secures the glenoid implant 900j in place.Because the glenoid implant 900j is an all-polymer implant, the polymer material allows the locking rim 940 to elastically flex as described. The elastic modulus of the locking rim 940 can be tailored by selecting an appropriate polymer formulation.

[0109] Alternatively, in some embodiments, the side wall 24E of the recess in the glenoid 24 can be simply straight without any undercuts, and the edge 941 of the locking rim 940 simply creates an interference fit with the reamed recess.

[0110] According to some embodiments, the locking rim 940 may be further configured with a plurality of compression relief notches 943 as shown. The compression relief notches 943 divide the locking rim 940 into a plurality of segments as shown. Preferably, the compression relief notches 943 are located at radially symmetric locations such that the locking rim 940 is divided into equal sized segments, thereby providing radially symmetric compression relief when the glenoid implant 900f is pressed into the recess in the glenoid cavity 24.

[0111] 41D-41F show examples of further embodiments of all-polymer glenoid implants including a locking rim 940 feature as a peripheral fixation feature, but configured with one of a variety of other possible fixation features extending from the base surface 920. FIG. 41D shows an all-polymer glenoid implant embodiment 900k including a locking rim 940 similar to glenoid implant 900j, but having three stabilizing posts 925' extending from the base surface 920 as one or more additional fixation features. FIG. 41E shows an all-polymer glenoid implant embodiment 900m also including a locking rim 940 similar to glenoid implant 900j, but having a keel 929 extending from the base surface 920 as one or more additional fixation features. FIG. 41F shows an all-polymer glenoid implant embodiment 900n also including a locking rim 940 similar to glenoid implant 900j, but the locking rim 940 does not have a compression relief notch.

[0112] 42A-42D show an embodiment 1000 of a metal-backed glenoid implant. The metal-backed glenoid implant includes a two-piece structure, a metal anchor 1000A, and a polymer insert 1000B, which are configured to lock together during the implantation process. The polymer insert 1000B can be formed of a high modulus polymer material, such as UHMWPE or PEEK. The metal anchor 1000A includes a disc portion 1011 that includes two faces, and a threaded screw portion 1012 that extends from the center of one of the two faces, which is a bone-facing base surface 1020. The surface opposite the base surface 1020 is the surface that receives the polymer insert 1000B. The plate portion 1011 is configured with a number of notches or notches 1013 along the periphery of the plate portion 1011. The polymer insert 1000B includes an articular surface 1030 and further includes a number of tabs 1002 extending from the polymer insert 1000B opposite the articular surface 1030. The tabs 1002 are configured to fit within corresponding notches 1013. The number and location of the tabs 1002 correspond to the number and location of the number of notches 1013 on the plate portion 1011. The polymer insert 1000B and the metal anchor 1000A lock together by aligning and inserting the tabs 1002 through the notches 1013. FIGS. 42E-42F are views of the metal anchor 1000A without the polymer insert 1000B.

[0113] During the implantation process, the metal anchor 1000A is first screwed into the bone 24, which has been prepared with a recess 24m (see FIG. 42H) having a tapped screw hole 24n. Once the metal anchor 1000A is screwed into place in the recess 24m, the polymer insert 1000B fits onto the plate portion 1011 of the metal anchor 1000A by first aligning the tabs with the notches 1013 and forcing the polymer insert 1000B towards the plate portion 1011 until the tabs 1002 are fully inserted through the notches 1013 and locked. Each of the tabs 1002 includes one or more compression relief slots 1002a, 1002b, with the tips 1002c of the tabs 1002 being larger than the notches 1013. This allows the tabs 1002 to compress when pressed into the notches 1013 and then spring back to their resting configuration once the polymer insert 1000B is fully engaged with the metal anchor 1000A. FIG. 42D is a side view of the polymer insert 1000B. Each of the tabs 1002 has a tip 1002c that is somewhat larger than the opening provided by the notch 1013 and a neck portion 1002d that is sized to match the size of the opening provided by the notch 1013. Thus, when the tabs 1002 are inserted into the notches 1013, the compression relief slots 1002a, 1002b compress the tip 1002c on each of the tabs 1002, allowing the tabs 1002 to fit through the notches 1013. As notch 1013 passes tip 1002c and engages neck portion 1002d, tip 1002c is decompressed and returns to its resting state, forming an interference fit between tip 1002c and plate portion 1011, holding polymer insert 1000B and metal anchor 1000A together. As can be seen in Figures 42A-42C, when metal anchor 1000A and polymer insert 1000B are assembled together, tip 1002c of tab 1002 protrudes from base surface 1020 of metal anchor 1000A.

[0114] 42G-42H show an example of a circular recess 24m that may be prepared in the glenoid bone to receive the metal-backed glenoid implant 1000. FIGS. 42G-42H show a graphic rendering of the three-dimensional shape of only the bone surface after the recess 24m is formed and the bulk bone material is removed. Referring again to FIG. 42G, the circular recess 24m has a bottom surface 24n. After the circular recess 24m is reamed into the bone, a screw hole 24o is tapped into the bottom surface 24n to receive the threaded portion 1012 of the metal anchor 1000A. Referring to FIG. 42H, a number of deeper recesses 24p are then reamed or drilled in an arrangement that matches the arrangement of the tabs 1002. These deeper recesses 24p provide clearance space for the tabs 1002 that protrude from the base surface 1020 of the metal anchor 1000A when the metal-backed glenoid implant 1000 is embedded in the bone. Once the recess 24m is fully prepared as shown in FIG. 42H, the embedding procedure involves two steps for the screwing action required to embed the glenoid implant 1000. First, the metal anchor 1000A is screwed into the recess 24m until the metal anchor 1000A is fully seated and the base surface 1020 of the metal anchor 1000A contacts the bottom surface 24n of the recess 24m. At this point, the metal anchor 1000A is seated at the bottom of the recess 24m. Next, the tab 1002 of the polymer insert 1000B is aligned with the notch 1013 in the metal anchor 1000A and the polymer insert 1000B is pushed into the recess 24m until the tip 1002c of the tab 1002 is pushed through the notch 1013 and snaps into place. The deeper recess 24p provides clearance for the tip 1002c of the tab 1002. Additionally, the tip 1002c of the tab 1002 is located within the deeper recess 24p, preventing the implant 1000 from rotating, so that the implant 1000 cannot be backed out by unscrewing.

[0115] 43A-43B show a porous metal-backed glenoid implant embodiment 1100. The glenoid implant embodiment 1100 includes a polymer insert 1100B that provides an articular surface 1130, overmolded directly onto a metal base plate 1100A. The polymer insert 1100B can be formed of a high modulus polymer material, such as UHMWPE or PEEK. The articular surface 1130 is for mating with the humeral head (anatomical or prosthetic). In the overmolded configuration for the implant 1100 shown in FIGS. 43A-43B, the metal base plate 1100A provides a bone-contacting base surface 1120. In some embodiments, the bone-contacting base surface 1120 is coated with a porous trabecular metal material, such as ADAPTIS™ from Wright Medical Technology, which can promote bone tissue ingrowth to enhance the attachment of the glenoid implant 1100 to the glenoid cavity after implantation. FIG. 43C identifies the bone-contacting base surface 1120. A cross-sectional view of the implant 1100 in FIG. 43D shows a porous trabecular metal coating P on the base surface 1120.

[0116] In some embodiments, the sidewalls 1110 of the polymer insert 1100B may be tapered to enhance circumferential fixation.

[0117] The polymer insert 1100B is overmolded onto the metal base plate 1100A, but the implant 1100 is an assembly configured to allow the polymer insert 1100B to be removed from the metal base plate 1100A if necessary. An exploded view of the implant 1100 in FIG. 43C shows that the implant 1100 includes three components: a base plate 1100A, a removal wedge screw 1140, and an overmolded polymer insert 1100B. The removal wedge screw 1140 is assembled into the metal base plate 1100A before the polymer insert 1100B is overmolded onto the metal base plate 1100A. The removal wedge screw 1140 is threaded into a threaded hole 1155 that extends through the metal base plate 1100A along the longitudinal axis LL of the metal base plate 1100A. The removal wedge screw 1140 includes a head portion 1141 and a threaded stem portion 1142. Next, the polymer insert 1100B is overmolded onto the base plate 1100A and the head portion 1141 of the removal wedge screw 1140. The head portion 1141 has a diameter that covers a substantial portion of the metal base plate 1100A, and the substantial portion of the surface area of ​​the metal base plate that is covered by the overmolded polymer insert 1100B is the head portion 1141. As will be described below, this configuration allows the overmolded polymer insert 1100B to be removed using the removal wedge screw 1140. As shown in cross-section in FIG. 43D, the removal wedge screw 1140 includes a tool-fitting socket 1145 in the center of its head portion 1141, which can be used to screw the removal wedge screw 1140 into or out of the threaded hole 1155. The tool-fitting socket 1145 can be configured to mate with one of various known types of screwdrivers. The overmolded polymer insert 1100B is provided with an access hole 1135 in the center of the insert 1100B that provides access to the tool engagement socket 1145. Figure 43F shows a straight-on view of the articular surface 1130 of the polymer insert 1100B.In this view, the tool fitting socket 1145 can be seen through the access hole 1135. In this example, the tool fitting socket 1145 is of the type that accepts the tip of a hexagonal screwdriver. By loosening the removal wedge screw 1140 from the threaded hole 1155 in the metal base plate 1100A, the head portion 1141 of the removal wedge screw 1140 lifts and removes the overmolded polymer insert 1100B from the base plate 1100A. To further enable this removal procedure, both the base plate 1100A and the polymer insert 1100B are configured with a pair of aligned slots 1132A and 1132B, respectively. These slots 1132A, 1132B are used to provide a counter torque when removing the removal wedge screw 1140. When the removal wedge screw 1140 is loosened, a suitable tool is inserted into the pair of slots 1132A, 1132B to hold the base plate 1100A and polymer insert 1100B in place and prevent them from rotating with the removal wedge screw 1140.

[0118] Figure 43E shows a detailed view of region B in Figure 43D. Figure 43E shows an overmolded polymer insert 1100B bonding to a metal base plate 1100A. In some embodiments, to increase the mechanical integrity of the bond between the two components, the base plate 1100A can include a groove 1150 that runs along the periphery of the base plate 1100A, resulting in a more intricate mating interface between the two components, for example resulting in a mechanically stronger bond interface than a straight interface.

[0119] In some embodiments, different fixation options such as modular posts, modular screws, keels, etc. may be used with this porous metal lined glenoid implant 1100. For example, a modular post 1162 or modular screws 1164, 1166 may be threaded into a screw hole 1155 as illustrated in FIG.

[0120] FIG. 43H illustrates an embodiment in which the implant 1100 can be converted to a reverse configuration shoulder implant. For this conversion, instead of the polymer insert 1100B, a tapered boss 1100C configured to mate with a glenosphere 1100G is attached to the metal base plate 1100A. In FIG. 43H, the metal base plate 1100A and the tapered boss 1100C are shown in cross section. In some embodiments, the tapered boss 1100C can be configured to attach to the metal base plate 1100A by a screw 1140a. The screw 1140a is threaded into a threaded hole 1155 in the metal base plate 1100A as shown. The tapered boss 1100C includes a hole in the center for receiving the screw 1140a, and the hole in the tapered boss 1100C includes a lip 1100C' that extends inward to capture the head of the screw 1140a. Thus, the head of the screw 1140a captures the tapered boss 1100C between the head of the screw and the metal base plate 1100A to secure the tapered boss 1100C. The head of the screw is provided with a tool engagement socket 1140a' configured to mate with one of various known types of screwdrivers. The tapered boss 1100C has a side wall 1110 that is tapered to mate with the glenosphere 1100G via a Morse taper type locking connection. The glenosphere 1100G includes a corresponding female tapered surface 1100G' that mates with the male tapered surface 1110. The tapered boss 1100C can also be configured with a threaded hole (not shown) that aligns with a slot 1132A in the metal base plate 1100A and can receive a screw for enhanced fixation.

[0121] 44A-45D show embodiments of glenoid implants using a peripheral ring fixation feature. With reference to FIG. 44A, glenoid implant 1200 includes a substantially circular body 1205 including an articular surface 1230 on one side and a bone-facing base surface 1220 on the opposite side. Along the periphery of circular body 1205 is a sidewall 1210 extending between two surfaces 1220 and 1230. Extending from bone-facing base surface 1220 is a peripheral fixation feature including a ring 1212 for mating with the glenoid cavity. As shown in cross-section in FIG. 44C, in some embodiments, articular surface 1230 is contoured to replicate the anatomical articular surface of the glenoid cavity. In some embodiments, articular surface 1230 can have a spherical contour, if desired. Bone-facing base surface 1220 has a spherical contour to mate with the glenoid cavity, provided with a complementary surface for receiving implant 1200.

[0122] The glenoid implant 1200 further includes a peripheral ring 1212 extending from the periphery of the bone-facing surface 1220 and mating with a prepared glenoid cavity with an annular recess 24q (see FIG. 45E) for receiving the peripheral ring 1212. In this embodiment 1200 of the glenoid implant, in which the implant body 1205 has a substantially circular shape, the peripheral ring 1212 is an extension of the side wall 1210. The peripheral ring 1212 is configured to enhance the quality of fixation to the glenoid cavity. The peripheral ring 1212 includes a groove 1213 on an outer surface of the ring 1212 and extending along the circumference of the ring 1212. The groove 1213 serves the purpose of retaining a quantity of bone cement along the circumference of the ring 1212 for coupling with the glenoid cavity. The peripheral ring 1212 may also include an optional further plurality of cement grooves 1214 along the outer surface of the ring 1212 adjacent to the groove 1213. The cement grooves 1214 are axially oriented. In a preferred embodiment, the cement grooves 1214 are disposed at radially symmetric locations along the ring 1212. The application of additional bone cement through the cement grooves 1214 is intended to prevent rotation of the glenoid implant 1200 after implantation.

[0123] In some embodiments, the glenoid implant 1200 may further include one or more additional fixation features extending from the base surface 1220. These additional fixation features may be any one of the following fixation features: posts, finned anchors, keels, etc. An example of a glenoid implant 1200 including a finned anchor 925 extending from the center of the base surface 1220 is shown in FIG.

[0124] In some other embodiments, the base surface 1220 of the glenoid implant 1200 can be a flat surface, as shown in the example cross section shown in Figure 44E. In some other embodiments, the outer surface of the peripheral ring 1212 is provided with flexible fins 1217 for cementless applications, as shown in the example cross section shown in Figure 44F. The fins 1217 serve the same function as the fins 927 on the finned anchor 925.

[0125] 45A-45B show another embodiment of glenoid implant 1200A including an implant body 1205A and a peripheral ring 1212 provided on the bone-facing base surface 1220 as a peripheral fixation element similar to glenoid implant 1200 shown in FIG. 44A. The peripheral ring 1212 for glenoid implant 1200A has the same structural features and includes all the optional features as the peripheral ring 1212 for glenoid implant 1200. However, in embodiment 1200A, implant body 1205A is not circular, but has a shape that reflects the contour of the anatomical glenoid. Similar to glenoid implant 1200, glenoid implant 1200A can also be configured with one or more additional fixation features extending from base surface 1220. These additional fixation features can be any one of the fixation features such as struts, finned anchors, keels, etc. FIGS. 45C-45D show an embodiment of glenoid implant 1200B including such additional fixation features. The glenoid implant 1200B also has a peripheral ring 1212 structure as a peripheral fixation element, similar to the glenoid implants 1200 and 1200A. The peripheral ring 1212 for the glenoid implant 1200B has the same structural features and includes all of the optional features as the peripheral ring 1212 for the glenoid implants 1200 and 1200A. The implant body 1205B is also shaped to reflect the contours of the anatomical glenoid. However, in the embodiment 1200B, the implant body 1205B includes two or more stabilizing struts 925' extending from a portion of the peripheral ring 1212 as one or more additional fixation features as previously described. The glenoid implant embodiments 1200, 1200A, and 1200B can be formed of a high modulus polymeric material, such as UHMWPE or PEEK.

[0126] FIG 45E illustrates how the glenoid 24 may be prepared with an annular recess 24q for receiving the glenoid implant shown in FIGS. 44A and 45A. The annular recess 24q is dimensioned to receive the peripheral ring 1212 of the glenoid implant 1200, 1200A. To receive the implant 1200 or 1200A having a curved base surface 1220, the glenoid 24 is first reamed with a curved reamer to prepare the glenoid 24 surface with a curved surface 24s that matches the curvature of the curved base surface 1220. The annular recess 24q is then reamed using a Bell-Saw type reamer 225.

[0127] FIG. 45F shows the glenoid implant of FIG. 44A or 45A implanted within the glenoid cavity 24 after the annular recess 24q has been formed.

[0128] 45G-45H are diagrams showing examples of Bellew-type reamers 225 and 226 that can be used to form the annular recess 24q in the glenoid fossa 24. FIG.

[0129] In addition to the peripheral ring fixation feature, the glenoid implant may have one or more additional non-peripheral fixation features, such as posts, finned anchors, or keels.

[0130] 46A-46B show an example glenoid implant 1300 according to another embodiment. The glenoid implant 1300 includes an implant body 1305 having an articular surface 1330 on one side and a bone-facing base surface 1320 on the opposite side. The glenoid implant 1300 further includes a peripheral ring 1312 disposed on the bone-facing base surface 1320 as a peripheral fixation element, similar to glenoid implants 1200 and 1200A. The glenoid implant 1300 also includes one or more struts 925'' extending from the base surface 1320 and located anywhere along the peripheral ring 1312 to further enhance fixation of the implant with the bone.

[0131] In some preferred embodiments, the one or more struts 925'' are positioned at radially symmetric locations along the peripheral ring 1312. It is believed that the radially spaced struts 925'' along with the peripheral ring 1312 minimize or substantially eliminate micromotion of the glenoid implant 1300 within the patient.

[0132] The peripheral ring 1312 and posts 925'' are porous trabecular metal structures that promote bone tissue ingrowth to enhance fixation of the glenoid implant 1300 in the glenoid cavity in cementless applications.

[0133] Referring to the cross-sectional view of FIG. 46B, in some embodiments, the strut 925'' is a composite structure having a solid metal core that provides suitable structural stability (i.e., rigidity) to the strut 925''. The solid metal core may be formed of a suitable alloy to which a porous trabecular metal coating may bond to provide lifetime structural reliability within a patient. The combination of the peripheral ring fixation feature 1312 and one or more additional fixation features 925'' having a solid metal core is referred to herein as being substantially formed of a porous trabecular metal material for promoting bone ingrowth when implanted within a patient.

[0134] The glenoid implant 1300 may be formed of a high modulus polymeric material such as UHMWPE or PEEK. In some embodiments, the implant body 1305 has a shape that reflects the contours of the anatomical glenoid. The high modulus polymeric material implant body 1305 may be overmolded onto a metal circumferential ring 1312 and a portion of the strut 925'' structure. The combination of the trabecular metal circumferential ring 1312 and one or more struts 925'' should enhance the primary fixation of the glenoid implant 1300 to the glenoid bone.

[0135] Although the devices, kits, systems, and methods have been described with respect to exemplary embodiments, they are not limited thereto. Rather, the appended claims should be construed broadly to include other variations and embodiments of the devices, kits, systems, and methods, which may be made by those skilled in the art without departing from the realm and scope of equivalents of the devices, kits, systems, and methods.

Claims

1. 1. A glenoid implant comprising: a circular body including an articular surface and an opposing anchoring surface, the anchoring surface being flat to contact and accommodate a corresponding flat surface in a prepared glenoid cavity; an annular sidewall extending around a circumference of the circular body, the annular sidewall having a plurality of retaining legs extending from the annular sidewall and folding back towards the articular surface to form a U-shaped leaf spring; The glenoid implant, wherein the annular side wall is configured to be press-fit into a recess provided in the glenoid cavity.

2. The glenoid implant of claim 1 , wherein the implant is formed of metal.

3. The glenoid implant of claim 2 , wherein the metal is CoCr or titanium.

4. The glenoid implant of claim 1 , wherein the implant is formed from a high modulus polymer.

5. The glenoid implant of claim 4 wherein the polymer is UHMW polyethylene.

6. The glenoid implant of claim 1 , wherein said circular body and said retention legs are integrally formed from the same material.

7. The glenoid implant of claim 1 , wherein the anchoring surface is coated with a porous metallic material.

8. 2. The glenoid implant of claim 1, wherein the annular sidewall is a grooved surface including a plurality of grooves with a blade formed between two adjacent grooves to enable the glenoid implant to be press-fit into the recess prepared in the glenoid.

9. The glenoid implant of claim 8 , wherein the implant is formed of metal.

10. The glenoid implant of claim 9, wherein the metal is CoCr or titanium.

11. The glenoid implant of claim 8 , wherein the anchoring surface is coated with a porous metallic material.

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