Total reverse shoulder system and method

Abstract

The reverse shoulder system can include, for example, a glenoid baseplate including a longitudinal axis, the glenoid baseplate further including a stem and a central channel in a sidewall of the stem. The stem can include a longitudinal axis. The longitudinal axis of the glenoid baseplate can be angled relative to the longitudinal axis of the stem, the longitudinal axis of the glenoid baseplate not being perpendicular to the longitudinal axis of the stem. Other components, including glenospheres, tools, and methods of use are also disclosed.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 816,708 as a patent application under 35 U.S.C. § 119(e), and this patent application is hereby incorporated by reference in its entirety.

Background Art

[0002] Shoulder arthroplasty is a medical procedure commonly performed for the treatment of osteoarthritis, rheumatoid arthritis, as well as for the treatment of several deformities associated with oncological indications and trauma. There are two main types of joints available to the surgeon for treatment: anatomical and reverse. In the anatomical type, the surgeon replaces the joint surface with an industrial material such that the joint surface has substantially the same shape as the natural anatomical structure. A stem can generally be fixed within the intramedullary canal of the humerus, and a metallic joint head can be firmly fixed to its proximal surface, the joint head having a convex joint surface adapted to articulate with a glenoid implant. The glenoid implant can include on its back (inner) side several pegs or struts or fins adapted to be firmly fixed within the glenoid fossa of the scapula, and on its front side a concave or flat joint surface adapted to articulate with the humeral head of the humeral implant.

[0003] When a reverse prosthesis is used, the joint surface is reversed in that a metal ball is firmly fixed to the glenoid fossa of the scapula and a concave joint surface is firmly fixed to the humerus, thereby reversing the joint pattern of the prosthesis.

[0004] The surgeon selects between the two types of prostheses by evaluating a number of patient conditions, including the level of pain, the patient's activity level, the deformation or severity of bone deterioration, the strength of the surrounding soft tissue, and the presence or absence of previous surgery, particularly the health and strength of the muscles and tendons of the rotator cuff. Rotator cuff disease is common among patients with shoulder arthritis. In this situation, it is generally observed that the absence of rotator cuff dysfunction leads to a situation where an anatomical shoulder replacement prosthesis is not sufficiently stabilized by the surrounding soft tissue. In this case, a reverse shoulder replacement prosthesis may be preferred in some cases because of the high inherent stability of the joint. In addition, the reverse prosthesis can advantageously utilize the remaining muscles in a way that can be more effective in the absence of other soft tissue structures by adjusting the position of the joint surface within the joint.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Means for Solving the Problems

[0006] In some embodiments, a reverse shoulder system is disclosed herein that includes any number of glenoid base plates including a longitudinal axis, the glenoid base plate further including a stem and a central channel within the sidewall of the stem, the stem including a longitudinal axis. The longitudinal axis of the glenoid base plate can be inclined with respect to the longitudinal axis of the stem, and the longitudinal axis of the glenoid base plate is not perpendicular to the longitudinal axis of the stem.

[0007] In some configurations, the glenoid baseplate includes a generally disc-shaped portion that extends radially outward from a central channel.

[0008] In some configurations, the stem includes a sidewall that extends upwardly relative to the disc portion.

[0009] In some configurations, the glenoid baseplate includes a periphery.

[0010] In some configurations, the periphery includes spaced anti-rotation features.

[0011] In some configurations, the anti-rotation features include slots.

[0012] In some configurations, the lower portion of the periphery includes a porous coating.

[0013] In some configurations, the lower surface of the generally disc-shaped portion includes a porous coating, while the upper surface does not include a porous coating.

[0014] In some configurations, the periphery and / or the lower surface of the baseplate includes a conical shape.

[0015] In some configurations, the lower surface of the baseplate is concave.

[0016] In some configurations, the stem includes a Morse taper lock above the uppermost portion of the generally disc-shaped portion of the glenoid baseplate.

[0017] In some configurations, the system further includes a glenosphere.

[0018] In some configurations, the glenosphere includes an upper domed surface that includes a rotation control feature configured such that an insertion tool can lock the glenosphere and the baseplate together to rotate the glenosphere and the baseplate together.

[0019] In some configurations, the rotation control feature includes a spline.

[0020] In some configurations, the system further includes a center screw and a locking nut.

[0021] In some configurations, the system further includes a central compression screw that is configured to be distal to and adjacent to the center screw and is non-integral with the base plate.

[0022] These drawings are exemplary embodiments and do not represent all possible embodiments of the present invention.

Brief Description of the Drawings

[0023]

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DETAILED DESCRIPTION OF THE INVENTION

[0024] In some embodiments, various embodiments of a total reverse shoulder system are disclosed herein, including various humeral trays, humeral bearings, an insert glenoid baseplate, a screw - locking insert, and a glenosphere. Glenoid surgical techniques are also described that utilize various tools including, but not limited to, a sizer / angle guide, a stem drill guide, a glenoid baseplate inserter, a calibrated central drill, a fixed or variable - angle peripheral drill guide, a central screw, a fixed - angle peripheral compression screw, a variable - angle peripheral screw, and a glenosphere inserter. The dimensions listed in the accompanying figures are merely non - limiting examples.

[0025] FIG. 1 shows an embodiment of the components of a total reverse shoulder system including a glenosphere 200 and a glenoid baseplate 102 that can be partially or fully inserted in some embodiments. The glenoid baseplate 102 is a generally disk - shaped structure and can include or be configured to mate with a central opening that defines a surface (e.g., integral with an elongate stem) or an elongate stem or post passing therethrough. The glenoid baseplate 102 can include a longitudinal axis that is inclined with respect to the longitudinal axis of the elongate stem 100. The longitudinal axis of the glenoid baseplate 102 can be at an angle such that it is generally oblique with respect to the longitudinal axis of the elongate stem 100. In some embodiments, this angle is an acute angle and not a right angle. The angle between the two intersecting longitudinal axes of each baseplate 102 and stem 100 can be, for example, about, at least about, or about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 degrees or less, or more or less than that, or a range including any two of the foregoing values.

[0026] Figure 2 shows various embodiments of a humeral tray that can be used in a total reverse shoulder system according to some embodiments. The humeral tray can include various inner diameters ID and outer diameters OD, including 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, or more or less ID and / or OD, and ranges including any two of the foregoing values. The tray can include one or more pegs, such as a central peg extending from the inner surface. The tray can be neutral or can include an extension (e.g., of thickness) that can be, for example, +2, 4, 6, 8, 10, 12mm, or a range including any two of the foregoing values. The tray can include various cross-sections, including an elliptical or circular cross-section. The tray can be compatible with the same polybearing surface in some cases. In some embodiments, one kit can include at least four different sized trays (34mm elliptical neutral, 34mm elliptical +6mm extension, 38mm circular neutral, 38mm circular +6mm extension).

[0027] FIG. 3 shows various humeral bearing components that can be utilized in a total reverse shoulder system according to several embodiments, including the humeral tray as illustrated and described in relation to FIG. 2. These bearing components can include, for example, a peripheral ring 302, a central recessed portion that can be contoured radially outwardly by the inner edge of the peripheral ring, and an inner cup-shaped portion 304. The peripheral ring can include a mark such as a slot or other marking 399 that indicates the highest point of the bearing component. Also shown are a recessed poly-dome 395 and a partial or complete annular barb 397 around the outer periphery of the bearing component. The bearing components can include various shapes including neutral, at an angle of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 degrees relative to horizontal, or a range including any two of the foregoing values. In some embodiments, the bearing component does not change the center of the joint. In some embodiments, the bearing component can include a sphere diameter of 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 mm, or more or less, or a range including any two of the foregoing values. In some embodiments, the system and method can include a misalignment in the range of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, or a range including any two of the foregoing values.

[0028] Figure 4 schematically shows one embodiment of a glenoid base plate configured to be inserted into the glenoid G as shown. The longitudinal axis of the base plate can be inclined, for example, with respect to the longitudinal axis of the stem / post as described with respect to FIG. 1, and can include a version change 499 that compensates for posterior bone defects. In some embodiments, the glenoid base plate includes a central channel configured to define a surface therethrough (e.g., integral with an elongate stem) or to receive the stem / post as shown. The glenoid base plate can include a generally conical shape with a concave lower surface configured to fit within the reamer surface of the glenoid bone, which advantageously enables the use of a single-pass reamer as opposed to a conventional glenoid base plate with a flat lower surface that requires a two-step reaming process. The post 493 can have a length of about, at least about, or about 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15 mm or more or less, or a range including any two of the foregoing values. In some embodiments, the central channel and / or the stem can include a female Morse taper 497 that includes a range incorporating any two of the foregoing values at an angle of about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more or less. As shown in the right figure of FIG. 4, the base plate can be configured to pivot around the stem / taper with arrow 495 for version correction and to enable a direct bone-to-implant interface without the need for augmentation. In some embodiments, the system can be configured to provide a version angle correction in a range of, for example, about 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20 degrees or more or less, or including any two of the foregoing values.In some embodiments, the base plate can have a diameter of about, at least about, or about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 mm or less, or more or less, or a range including any two of the foregoing values. The base plate can advantageously pivot around the central stem with a Morse taper for version correction, enabling a direct bone and implant interface.

[0029] FIG. 5 schematically shows an embodiment of a glenoid base plate 500 configured to be inserted into a glenoid (not shown in FIG. 5). The longitudinal axis of the base plate 500 can be inclined with respect to the longitudinal axis of the stem / post 510, for example, as described with respect to FIGS. 1 and 4 above. The base plate 500 can have a generally arcuate periphery. The periphery can include spaced anti-rotation slots 521 oriented generally transverse to the longitudinal plane of the base plate 500. In some embodiments, the periphery of the base plate 500 can taper (e.g., decrease) in diameter from an upper to a lower dimension. A central channel can extend through the base plate 500 and can include a sidewall or lip 511 that extends upwardly somewhat similar to the slope of the side of a volcano. The central channel can be configured to define a surface (e.g., integral with an elongate stem) or to receive the stem / post 510 therethrough. The base plate 500 can also include a plurality of regularly or irregularly spaced secondary (peripheral) channels 555 spaced radially outward from the central channel of the base plate and configured to receive fixed and variable angle screws therethrough. The secondary channels 555 can be asymmetric and can include an upwardly extending portion 556 that can extend into and block a sidewall or lip 511 that extends above the central channel of the base plate 500. The base plate 500 can include, for example, a porous coating 585 that promotes in-growth of bone, either entirely or only on a portion of the periphery and / or lower surface (e.g., bottom surface) of the base plate 500.

[0030] Referring further to FIG. 5, the stem / post 510 can have an internal taper, such as a Morse taper, of about, at least about, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 degrees or less, or more or less, or a range including any two of the foregoing values. The stem / post 510 can also include a rotation control feature 545 that is along the outer diameter of the stem / post 510 and is above the uppermost surface of the sidewall 511 of the central channel of the Glenoid base plate 500 as shown in some embodiments. The rotation control feature 545 can be non-circular or non-arc-shaped, such as hexagonal as shown. The stem / post 510 can also include a central channel and can include a Morse taper lock 535 configured to mate with a Glenosphere (not shown). The Morse taper lock can extend upwardly relative to the uppermost surface of the sidewall 511 of the central channel of the Glenoid base plate 500. The central channel of the stem / post 510 can be configured to accommodate a primary screw (not shown) therethrough, which is a variable angle primary screw and can optionally be locked.

[0031] FIG. 6 shows a threaded locking insert 600 for the central channel of a stem / post according to some embodiments. The insert 600 includes an outer male thread 602 and can be configured to enter into the central channel of the base plate. The outer diameter of the insert can also include a hexagonal portion 604 at the upper end of about, at least about, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm or less or more or less, or a range including any two of the foregoing values. The hexagonal portion 604 can be configured to function as a rotation control feature in some embodiments. The insert 600 can also include an internal thread 608 configured to receive an auxiliary Glenosphere locking screw (not shown) and, for example, a spherical surface 612 at its lower end for locking a variable angle screw.

[0032] Figure 7 shows various views of a glenosphere according to some embodiments. The left image shows a glenosphere with a rotation control feature 702, which includes splines such as asymmetric splines, advantageously enabling rotation control around the splines and allowing an insertion tool to lock and rotate the glenosphere together with other components such as a base plate. The glenosphere can also include one or more markings such as an eccentric rotation mark 704. The glenosphere can include a hollow strut with a substantially domed surface 714, a cavity 706 with a downward opening 708, and a Morse taper lock 711 into the base plate. The glenosphere can be a complete hemisphere or can be shorter than a complete hemisphere by a distance 720 of about, at least about, or about 0.5 mm, 0.75 mm, 1 mm, 1.25 mm, 1.5 mm, 1.75 mm, 2 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm or less, or more or less, or in a range including any two of the foregoing values.

[0033] Referring further to Figure 7, in some embodiments, the glenosphere can include an articulation diameter of about, at least about, or about 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 mm or less, or more or less, or in a range including any two of the foregoing values. In some embodiments, the system and method can include a misalignment and / or eccentricity dimension of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, or in a range including any two of the foregoing values. In some embodiments, the glenosphere has a neutral shape. In some embodiments, the glenosphere 724 is offset, for example, by about +3 mm or about 6 mm. In some embodiments, the glenosphere 722 has an eccentricity dimension between about 2 mm and about 4 mm. In some embodiments, a secondary locking screw can be utilized with the glenosphere.

[0034] FIG. 8 shows a schematic cross-section of a fully assembled grenosphere with locking bolts, according to some embodiments, along with a base plate. The grenosphere can include a central channel therethrough, including, for example, a rotational control feature 702 at the top that can be described elsewhere in this specification. The central channel can also include a threaded surface 808 for an inserter / head extractor, such as below the rotational control feature 702, and optionally can accommodate a secondary locking screw at 810 to push and / or rotate with a strut of the base plate. The strut of the grenosphere can be at least partially disposed within the central channel of the base plate as shown. A central retaining screw / locking nut 814 can be connected to, and in some cases removably attachable to, the central channel of the solenoid base plate and can have an end adjacent to or in direct contact with an end of a central compression screw 816, which can have a diameter of, for example, about, at least about, or about 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 mm or less, or more or less, or a range including any two of the foregoing values. The central compression screw is configured to be inclined with respect to the base plate and can advantageously enable the use of locking screws.

[0035] Figures 8A - 8U illustrate glenoid surgical techniques according to several embodiments, which can include any number of the following operations. Figure 8A shows a glenoid surface with an A3 - E3 defect. A sizer / angle guide can be positioned as in Figure 8B. A wire guide / wire can be positioned in Figure 8C. The wire guide and sizer / angle guide can be removed as in Figure 8D. The glenoid surface can then be reamed for the baseplate as in Figures 8E and 8F. A stem drill guide can then be positioned and adjusted in Figure 8G. A hole for the stem can then be drilled in Figures 8H and 8I. The baseplate can then be inserted as shown in Figure 8J, and the screw - type rod can be removed as shown in Figure 8K. In Figure 8L, a central cavity can be drilled to determine the length of the central screw to be placed. The drill can be removed in Figure 8M, a screw and screwdriver can be placed through the shaft, and the screw can be tightened in Figure 8N. The baseplate inserter handle can be removed in Figure 8O, and holes can be drilled for the peripheral locking screws in Figure 8P. Holes can be drilled for the variable - angle screws as shown in Figure 8Q. Peripheral screws can be inserted and tightened in Figure 8R. A central locking screw and a secondary locking nut can be inserted and tightened in Figure 8S. A glenosphere can be inserted in Figure 8T, and a locking bolt can be inserted and tightened in Figure 8U.

[0036] Figure 9 shows an embodiment of a sizer / angle guide that includes a downward - tilt mechanism 902. This mechanism can be fixed at a set angle (e.g., about 0, 5, 10, 15, 20, 25 degrees, or a range including any two of the aforementioned values), or in some embodiments it is adjustable. This mechanism is circular or elliptical in shape in some embodiments and can include slots (e.g., rear or lower - rear) that allow for removal. The downward - tilt mechanism 902 can include set screws with calibrated windows, or in some cases individual depth screws.

[0037] FIG. 10 shows an embodiment of a stem drill guide that can include a diameter of about, at least about, or about 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 mm or less or more or less, or a range including any two of the foregoing values. The drill guide can include, for example, a version angle of about 0, 5, 10, 15, 20, 25 degrees or more or less, or a range including any two of the foregoing values. In some embodiments, the greater the version angle, the more stem inclination is generated when rotation occurs.

[0038] FIG. 11 schematically shows a stem angle change with rotation adjustment (e.g., about 30 degrees) and an inclination version plate (e.g., about 15 degrees) as a non-limiting example. Front-to-back and bottom-to-top views are shown.

[0039] FIG. 12 schematically shows a glenoid base plate inserter (alone on the left, with the base plate on the right) according to some embodiments. The base plate inserter can be configured in any number of positive rotation controls, a slim design that allows visualization through the screw hole to know when it is fixed, and / or a multi-functional handle that allows a central screw hole to be drilled and a central screw to be inserted.

[0040] FIG. 13 schematically shows a calibrated central drill according to some embodiments. Calibrated marks 902 at desired increments (e.g., 5 mm increments in some embodiments) spaced near the proximal end of the device can help determine the required length of the central screw. The calibrated length can start, for example, at about, at least about, or about 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm or less, or more or less, including any two of the foregoing values, and advantageously, one surgical step can be omitted.

[0041] Figure 14 schematically shows a diagram of a fixed-angle peripheral drill guide according to some embodiments. The drill guide can be configured to fit the shape of a polygonal portion (e.g., octagon) at the top of the base plate, and the operator can then determine which fixed-angle screw to drill.

[0042] Figure 15 schematically shows a diagram of a variable-angle peripheral drill guide according to some embodiments.

[0043] Figure 16 schematically shows side and top views of a central screw according to some embodiments, including a head 1601, a threaded shaft 1602, and a distal taper portion. In one embodiment, the screw can have a 6.5 mm head and a 6 mm threaded shaft, but various size ranges and increments are possible, including diameters of about, at least about, or about 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10 mm or less, or more or less, or ranges including any two of the foregoing values. In some embodiments, the central screw can include all or the working length of a range of about, at least about, or about 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 mm or more or less, or ranges including any two of the foregoing values. In some embodiments, anodization of the screw can be optionally present to help distinguish the screw. The screw head can have various internal feature shapes 1603, including a T20 hex lobe configuration in some embodiments.

[0044] Figure 17 schematically shows side and top views of a fixed-angle circumferential compression screw, according to some embodiments, including a head 1701, a double-thread 1703 proximal to the threaded shaft 1702, and a distal tapered portion. The screw can be of various size ranges and increments and can include a T20 hex lobe or other internal head feature shape 1704 as described elsewhere in this specification. In one embodiment, the head can have a diameter of about 5.7 mm and a threaded shaft diameter of 4.5 mm, or the dimensions listed elsewhere in this specification, such as, for example, in relation to Figure 16.

[0045] Figure 18 schematically shows side and top views of a variable-angle circumferential screw, according to some embodiments, including a head 1801, a threaded shaft 1802, and a distal tapered portion. The screw can be of various size ranges and increments and can include a T20 hex lobe or other internal head feature shape 1803 as described elsewhere in this specification. In one embodiment, the head can have a diameter of about 5.7 mm and a threaded shaft diameter of 4.5 mm, or the dimensions listed elsewhere in this specification, such as, for example, in relation to Figure 16 or Figure 17.

[0046] Figure 19 schematically shows a diagram of a glenosphere inserter, according to some embodiments, which can include a distal end with features complementary to the splines on the glenosphere, as described, for example, in relation to Figure 7. The glenosphere inserter can be configured to advantageously provide secure attachment to the glenosphere, enable secure rotational control during insertion, and / or may involve a secondary insertion step after removal.

[0047] In some embodiments, embodiments of the present invention can be used or modified by taking advantage of certain advantages, such as using an insertion glenoid fixation technique in an anatomical shoulder arthroplasty, as described in, for example, Gunther U.S. Patent Nos. 8,007,538 and / or 8,778,028, which are hereby incorporated by reference in their entirety. Further, embodiments of the present invention can be used or modified by taking advantage of systems and methods, such as those disclosed in, for example, Ball U.S. Patent Application Publication No. 2018 / 0368982, which is hereby incorporated by reference in its entirety.

[0048] Of course, in light of the above teachings, various other modifications, adaptations, and alternative designs are possible. Thus, it should be understood at this point that the invention can be practiced in ways other than those specifically described herein within the scope of the appended claims. It is contemplated that various combinations or sub - combinations of the specific features and aspects of the embodiments disclosed above can be created and still fall within one or more of the inventions. Further, the disclosure herein of any particular feature, aspect, method, characteristic, feature, quality, attribute, element, etc. related to one embodiment can be used in all other embodiments defined herein. Thus, it should be understood that the various features and aspects of the disclosed embodiments can be combined with or replaced by each other to form various modes of the disclosed invention. Thus, it is intended that the scope of the invention disclosed herein should not be limited by the specific disclosed embodiments described above. Also, while the invention is susceptible to various modifications and alternative forms, specific examples thereof are shown in the drawings and described in detail herein. However, the invention should not be limited to the specific forms or methods disclosed, but rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Any method disclosed herein need not be performed in the order described. The methods disclosed herein include certain actions taken by an implementer, but can also include, explicitly or implicitly, any third - party instructions for these actions. For example, an action such as "inserting an implant into the glenoid fossa" includes "instructing the insertion of an implant into the glenoid fossa". The scope disclosed herein also encompasses any and all overlaps, sub - ranges, and combinations thereof. Words such as "up to", "at least", "greater than", "less than", "between", etc. include the recited numbers.Numbers preceded by terms such as "about", "approximately", and "substantially" as used herein include the recited number (e.g., about 10% = 10%) and also represent amounts that are close to the recited amount that still perform the desired function or achieve the desired result. For example, the terms "about", "approximately", and "substantially" may refer to amounts within less than 10%, less than 5%, less than 1%, less than 0.1%, and less than 0.01% of the recited amount.

Explanation of Signs

[0049] 100 Stem 102 Base Plate 200 Glenosphere 302 Peripheral Ring 304 Inner Bowl-shaped Portion 306 Ring Shield 397 Annular Barb 399 Marking 493 Strut 497 Morse Taper 499 Version Change 500 Base Plate 510 Stem / Strut 511 Side Wall 521 Anti-rotation Slot 535 Morse Taper Lock 545 Rotation Control Feature 555 Secondary Channel 556 Upper Extending Portion 585 Porous Coating 600 Insert 602 Male Thread 604 Hexagonal-shaped Portion 608 Female Thread 612 Spherical Surface 702 Rotation Control Feature 704 Eccentric Rotation Mark 706 Cavity 711 Morse Taper Lock 714 Substantially Dome-shaped Surface 722 Glenosphere 724 Grenosphere 808 Threaded surface 814 Central stop screw / Locking nut 816 Central compression screw 902 Lower inclination mechanism 1601 Head 1602 Threaded shaft 1603 Internal feature shape 1701 Head 1702 Threaded shaft 1703 Double-threaded screw 1704 Internal head feature shape 1801 Head 1802 Threaded shaft 1803 Internal head feature shape

Claims

1. A glenoid base plate including a longitudinal axis and including the glenoid base plate further including a stem and a central channel within the side wall of the stem, the stem including a longitudinal axis, the longitudinal axis of the glenoid base plate being inclined with respect to the longitudinal axis of the stem, the longitudinal axis of the glenoid base plate not being perpendicular to the longitudinal axis of the stem, the glenoid base plate including a generally disc-shaped portion extending radially outward from the outer surface of the stem in a radially outer direction of the central channel, the upper surface of the generally disc-shaped portion not being perpendicular to the longitudinal axis of the stem, the stem including a side wall extending along an upper portion of the stem forming the central channel and an upwardly extending portion, the upwardly extending portion being continuous from the side wall to the upper surface of the generally disc-shaped portion, the upper surface of the generally disc-shaped portion being parallel to the lower surface of the generally disc-shaped portion, a reverse shoulder system.

2. The system according to claim 1, wherein the glenoid base plate includes a periphery.

3. The system according to claim 2, wherein the periphery includes spaced anti-rotation features.

4. The system according to claim 3, wherein the anti-rotation features include slots.

5. The system according to claim 2, wherein a lower portion of the periphery includes a porous coating.

6. The system according to claim 1, wherein the lower surface of the generally disc-shaped portion includes a porous coating, but the upper surface does not include a porous coating.

7. The system according to claim 2, wherein the periphery and / or lower surface of the glenoid base plate includes a conical shape.

8. The system according to claim 1, wherein the lower surface of the glenoid base plate is concave.

9. The system according to claim 1, wherein the stem includes a Morse taper lock above the uppermost portion of the generally disc-shaped portion of the glenoid base plate.

10. The system according to claim 1, further including a glenosphere.

11. The system according to claim 10, wherein the glenosphere includes an upper domed surface including a rotation control feature configured such that an insertion tool can lock the glenosphere and the glenoid base plate together to rotate the glenosphere and the glenoid base plate together.

12. The system of claim 11, wherein the rotation control feature includes a spline. **Claim 13** The system of claim 10, further comprising a center screw and a locking nut. **Claim 14** The system of claim 13, further comprising a central compression screw configured to be non-integral with the glenoid base plate and distally disposed adjacent to the center screw.

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