WO2024258699A1

WO2024258699A1 - Tapered protrusions on arthroplasty implant stem

Info

Publication number: WO2024258699A1
Application number: PCT/US2024/032512
Authority: WO
Inventors: Kenneth KONYA; Forrest A. JAMES; Jacob Stegman
Original assignee: Smith and Nephew Orthopaedics AG; Smith and Nephew Asia Pacific Pte Ltd; Smith and Nephew Inc
Current assignee: Smith and Nephew Orthopaedics AG; Smith and Nephew Asia Pacific Pte Ltd; Smith and Nephew Inc
Priority date: 2023-06-13
Filing date: 2024-06-05
Publication date: 2024-12-19
Anticipated expiration: 2025-12-13

Abstract

Systems and methods for shoulder arthroplasty including a stem (101) having a proximal portion (103), a distal portion (102), and a body (110) disposed between the proximal portion and the distal portion, where the proximal portion includes a cavity (104) extending toward the body. The system further includes a liner (120) configured for coupling within the cavity of the stem. The stem includes one or more protrusion (111) extending from a base (114) of the cavity, where each protrusion has a profile that tapers from a first width (t1) at the base to a second width (t2) that is narrower that the first width. The liner includes one or more recess (121), each recess being configured to receive therein one of protrusions, and each recesses having a width that is narrower than the first width and wider than the second width.

Description

TAPERED PROTRUSIONS ON ARTHROPLASTY IMPLANT STEM

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a non-provisional of, and claims the benefit of the filing date of, U.S. provisional patent application number 63/472,692, filed June 13, 2023, entitled “TAPERED PROTRUSIONS ON SHOULDER PROSTHESIS;’ U.S. provisional patent application number, 63/524,243, filed June 30, 2023, entitled “HUMERAL IMPLANT LINER REMOVAL,” and U.S. provisional patent application number 63/547,432, filed November 6, 2023, entitled “TAPERED PROTRUSIONS ON ARTHROPLASTY IMPLANT STEM,” the entireties of which applications are incorporated by reference herein.

FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to medical implant devices. More particularly, the subject matter disclosed herein relates to configurations of a stem of a shoulder arthroplasty implant system.

BACKGROUND OF THE DISCLOSURE

[0003] Shoulder replacement implants are used for restoration of functionalities of shoulders as well as to treat a variety⁷ of degenerative conditions and injuries. Shoulder replacement implants typically come in two designs: anatomic and reverse. Anatomic shoulder implants are used for restoration of natural kinematics of a shoulder by replacing its humeral head and glenoid with similarly shaped prosthetic designs that recreate normal anatomy. The anatomic shoulder implant often has a spherical humeral head and a shallow concave glenoid that articulates with the spherical head. As part of an implantation procedure, an anatomic shoulder implant's stem is securely placed down the shaft of the humerus and the spherical head is often fixed to the stem using a mechanical taper press fit. The glenoid prosthetic component (made from a polymer, e.g., ultra-high molecular weight polyethylene (UHMWPE)) is either cemented directly into the remaining intact glenoid or affixed to a metallic tray, which is secured to the native glenoid bone using bone screws, cement, or similar attachment methods.

[0004] In the reverse shoulder implant procedure, the implant’s spherical surface is placed on the remaining intact glenoid and its concave articular surface is placed on the humerus. The implant also includes a stem that is securely placed down the shaft of the humerus. A concave articular surface is fixed to the stem using a mechanical lock.

[0005] In existing implants, a liner (e.g., a polymer liner) serves as a concave articular surface that interfaces with the metal spherical head on the glenoid. In conventional implants, however, the coupling of the liner to the stem can allow for micromotion and rotation, which can raise concerns with stability of the joint and wear of the components.

[0006] It is with respect to these and other considerations that the present disclosure can be useful.

SUMMARY OF THE DISCLOSURE

[0007] This Summary' is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. [0008] A system for shoulder arthroplasty is disclosed. The system can include a stem including a proximal portion, a distal portion, and a body disposed between the proximal portion and the distal portion, where the proximal portion includes a cavity extending toward the body. The system can further include a liner. In some examples, the liner may be configured for coupling within the cavity of the stem. In one example, the liner may be secured with respect to the stem via one or more protrusions. The protrusions may extend from either the base of the cavity in which the liner will be seated and/or the one or more protrusions may extend from the liner surface that will be seated within the stem cavity. In a specific example, the stem may include one or more protrusion extending from a base of the cavity. It is possible for each of the one or more protrusion to have a profile that tapers from a first width at the base to a second width that is narrower that the first width. The liner may include one or more recess, each of the one or more recess being configured to receive therein one of the one or more protrusion, and each of the one or more recesses having a width that is narrower than the first width and wider than the second width. In an alternate configuration, it is possible for liner to include one or more protrusion corresponding to one or more recess in the stem, where each of the one or more protrusion has a profile that tapers from a first width that is wider than a width of the one or more recesses to a second width that is narrower than the width of the one or more recess.

[0009] A method of for shoulder arthroplasty is also disclosed. The method can include inserting a stem into a patient’s humerus during a surgical procedure, the stem including a proximal portion, a distal portion, and a body disposed between the proximal portion and the distal portion, wherein the proximal portion includes a cavity extending toward the body. The method can further include coupling a liner to the proximal portion of the stem by causing a portion of the liner to cooperate with a recess.

In a specific example, the method may include inserting a projection of the liner within the cavity’ of the stem. For this method, the stem can include one or more protrusion extending from a base of the cavity, where each of the one or more protrusion has a profile that tapers from a first width at the base to a second width that is narrower that the first width, and the liner can include one or more recess, with each of the one or more recess being configured to receive therein one of the one or more protrusion and each of the one or more recesses having a width that is narrower than the first width and wider than the second width. In this way, coupling the liner to the proximal portion of the stem can involve coupling each of the one or more recess with one of the one or more protrusion. In an alternate configuration, it is possible for liner to include one or more protrusion corresponding to one or more recess in the stem, where each of the one or more protrusion has a profile that tapers from a first width that is wider than a width of the one or more recesses to a second width that is narrow er than the width of the one or more recess.

[0010] In any preceding or subsequent example, the liner can include a concave articular surface configured for use in a reverse shoulder implant. Alternatively, in some examples, the liner can include a base of a substantially spherical head configured for use in an anatomic shoulder implant.

[0011] In any preceding or subsequent example, the cavity can include one or more edge defining an outer wall of the cavity, and the projection can be configured to engage the one or more edge. In particular, in some examples, a diameter of the projection is greater than a diameter of the cavity such that the projection is configured to engage the one or more edge in a friction-fit arrangement. Alternatively, or in addition, in some examples, the cavity includes an undercut extending radially outward beneath the one or more edge, and the projection includes a flange that extends radially outward from the projection, wherein, when the projection is coupled within the cavity, the flange is configured to pass beneath the one or more edge and into the undercut.

[0012] In any preceding or subsequent example, the one or more protrusion may be a ring. In a specific example, the ring may be a substantially continuous ring. The one or more recess may include a corresponding ring-shaped recess. As discussed herein, in some examples, the ring is provided on the stem, and the corresponding ring-shaped recess is formed on the liner. Alternatively, in some examples, the ring is provided on the liner, and the corresponding ring-shaped recess is formed on the stem.

[0013] In some examples, the present disclosure relates to a method for removing a liner from a stem of a shoulder implant system. The method may include selecting an osteotomy sizer that approximately matches the circumference (and/or the diameter) of the liner and centrally positioning the osteotomy sizer on the top surface of the liner, while centrally holding the osteotomy sizer on the liner, drilling an opening in the liner through the center of the osteotomy sizer, positioning a screw into the drilled opening and threading the screw through the opening until the screw contacts a bottom of the stem’s well, continue threading the screw until the liner disengages from the stem, and removing the liner and the screw.

[0014] In any preceding or subsequent examples, the osteotomy sizer may be selected from a plurality of osteotomy sizers.

[0015] In any preceding or subsequent examples, the opening may be made using a glenoid guide pin and/or a drill bit using a drill. [0016] In any preceding or subsequent examples, the opening may be a pilot opening made using the glenoid guide pin. The opening may be an opening made through the liner using at least one of the: the glenoid guide pin, the drill, and any combination thereof.

[0017] In any preceding or subsequent examples, the diameter of the glenoid guide pin and/or the drill may be less than an interior diameter of the stem’s well.

[0018] In any preceding or subsequent examples, the diameter of the screw may be less than the interior diameter of the stem’s well.

[0019] In any preceding or subsequent examples, the length of the screw may be greater than a depth of an interior cavity of the stem, including the depth of the stem’s well.

[0020] In any preceding or subsequent examples, continuous threading of the screw causes interaction between a tip of the screw and a bottom surface of the stem’s well and pushing of the screw away from the bottom surface of the stem’s well, causing disengaging of the liner from the stem.

[0021] Examples of the present disclosure provide numerous advantages. For example, the tapered shape of the one or more protrusion can help secure the liner into place, acting as fmgers/anchors to reduce micromotion in each localized area and limit rotation of the liner with respect to the stem. In addition, the tapered shape can facilitate alignment of the liner with the stem and provide tactile feedback to a user when coupling the liner to the stem.

[0022] Further features and advantages of at least some of the examples of the present disclosure, as well as the structure and operation of various examples of the present disclosure, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By way of example, specific examples of the disclosed device will now be described, with reference to the accompanying drawings, in which:

[0024] FIG. 1 illustrates a side perspective view of a component of a shoulder implant system in accordance with one or more features of the present disclosure;

[0025] FIG. 2 illustrates a top perspective view of a proximal portion of a stem of a shoulder implant system in accordance with one or more features of the present disclosure;

[0026] FIG. 3 illustrates perspective views of a stem and an insert of a shoulder implant system in accordance with one or more features of the present disclosure;

[0027] FIGS. 4 and 5 illustrate side cutaway views of a stem of a shoulder implant system in accordance with one or more features of the present disclosure;

[0028] FIG. 6 illustrates a top perspective view of a proximal portion of a stem of a shoulder implant system in accordance with one or more features of the present disclosure;

[0029] FIG. 7 illustrates a side cutaway view of a stem of a shoulder implant system in accordance with one or more features of the present disclosure;

[0030] FIGS. 8A and 8B illustrate side perspective views of a stem being used in both a reverse and anatomic shoulder implant system in accordance with one or more features of the present disclosure;

[0031] FIGS. 9A and 9B illustrate perspective views of the liner and the stem during liner removal, in accordance with one or more features of the present disclosure; [0032] FIGS. 10A and 10B illustrate cross-sectional views of the liner and the stem during liner removal, in accordance with one or more features of the present disclosure; and

[0033] FIG. 11 illustrates an example process for removal of a liner from a stem of an implant, in accordance with one or more features of the present disclosure.

[0034] The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict various examples of the disclosure, and therefore are not considered as limiting in scope. In the drawings, like numbering represents like elements.

DETAILED DESCRIPTION

[0035] Various features of a shoulder implant system will now be described more fully herein with reference to the accompanying drawings, in which one or more features of the shoulder implant system will be shown and described. It should be appreciated that the various features can be used independently of, or in combination, with each other. It will be appreciated that the shoulder implant system as disclosed herein can be embodied in many different forms and can selectively include one or more concepts, features, or functions described herein. As such, the shoulder implant system should not be construed as being limited to the specific examples set forth herein. Rather, these examples are provided so that this disclosure will convey certain features of the shoulder implant system to those skilled in the art.

[0036] As stated above, shoulder implants are intended to restore the natural kinematics of a patient's shoulder by replacing the patient’s humeral head and/or glenoid with similarly shaped orthopedic implants that recreate normal anatomy. In accordance with one or more features of the present disclosure, a shoulder implant system that provides improved resistance to micromotion and rotation is disclosed.

[0037] FIG. 1 illustrates an example of a shoulder implant system, generally designated 100. Moreover, the illustrated system 100 is shown as a reverse shoulder implant configuration. The shoulder implant system 100 includes a stem 101 coupled to a cup or liner 120. In some examples, the liner 120 is a polymer liner. Specific material options include, but are not limited to, ultra-high-molecular- eight polyethylene (UHMWPE) (e.g.. cross-linked, non-cross-linked, stabilized with Vitamin E). The stem 101 can be arranged and configured for insertion into the patient’s humerus during a surgical procedure (e.g., arthroplasty). In particular, the stem 101 can be appropriately sized and/or shaped for such insertion. The stem 101 can be arranged and configured to be a unitary⁷ structure, which can be helpful during its manufacturing process.

[0038] As illustrated in FIG. 1, the stem 101 includes a distal portion 102, a proximal portion 103, and a body 110 disposed between the distal portion 102 and the proximal portion 103. In some examples, the distal portion 102 can be narrower than the proximal portion 103. The body 110 can be arranged and configured to be inserted into a cavity (not shown) formed in the humeral bone during the surgical procedure, with the distal portion 102 being inserted first. In some cases, the body 110 can be angled and have a partially flattened profile that can aid during positioning of the implant system 100 in the humeral bone.

[0039] Referring to FIG. 2, a perspective view of the proximal portion 103 of the stem is shown without the liner 120. The proximal portion 103 includes a cavity 104 that extends partially into the body 110 of the stem 101. In some examples, the cavity

104 has a stepped internal configuration, with its internal diameter varying from a relatively larger diameter at the rim 105, positioned at the proximal portion 103, to a relatively smaller diameter at abase 114 of the cavity 104 that is recessed inward toward the body 110. In addition, in some examples, the cavity 104 includes a well 108 (e.g., a morse taper) that is further recessed into the body 110. The well 108 can have a diameter that is smaller than that of the base 114. The well 108 can be used during the surgical procedure for aligning various components of the system 100. such as, for example, a glenoid guide pin (not shown).

[0040] Referring again to FIG. 1, the liner 120 can include an inwardly projecting curved articulating surface 122 (See also, e.g., FIG. 8A). The curvature of the surface 122 can be arranged and configured to project toward the cavity 104 with the lowest point on the curvature being positioned substantially proximate to the well 108. The surface 122 can be arranged and configured to interact with other components of shoulder prosthesis to enable a more natural range of motion.

[0041] In some examples, the cavity' 104 also includes one or more edge 106 disposed around an internal circumference of the cavity' 104 and defining a wall of the cavity' 104. The edge 106 can be arranged and configured to interact with a corresponding projection 126 that extends from an interfacing bottom surface of the liner 120 to ensure proper seating and/or positioning of the liner 120 with respect to the proximal portion 103 of the stem 101. In some examples, the external dimensions of the projection 126 are slightly larger than the internal dimensions of the edge 106 such that, when the liner 120 is positioned onto the stem 101, the projection 126 and the edge 106 are arranged and configured to create a friction-fit coupling to secure at least a portion of the liner 120 within the stem 101. In some examples, the projection 126 further includes an extension 128 that, when positioned on the stem 101, is configured to be inserted (at least partially) into the well 108 of the cavity 104.

[0042] In some examples, the liner 120 can be removable and interchangeable to achieve a desired configuration of the implant 100. In some examples, one or more liners 120 can be used for a single, corresponding stem 101. Each liner 120 can have a particular size, articulating surface diameter, offset, and/or any other characteristics that can be selected to best correspond to the anatomy of the patient. This configurability permits a surgeon to select an appropriate liner 120 for placement during shoulder reconstruction surgery. Alternatively, or in addition, if an additional liner height can be desired, a spacer can be positioned between the liner 120 and the stem 101.

[0043] Referring to FIGS. 3 and 4, to help retain and/or orient the liner 120 within the cavity 104, one or more protrusion 111 can be provided on the base 114 of the cavity- 104. Correspondingly, the projection 126 of the liner 120 can include one or more recess 121 that is configured to matingly receive the one or more respective protrusion 111 upon positioning of the spacer 120 on the stem 101. As shown by the arrows and circles in FIG. 3, two protrusions 111 and two recesses 121 can be provided. In other examples, there may be a single protrusion-recess pair. In other examples, three or more protrusion-recess pairs may be provided. Increasing the number of protrusions can increase the amount of contact based on surface area and tolerances, although increasing the number can also make assembly of the components more challenging due to the increased number of elements to align simultaneously. In some examples, the one or more protrusion 111 is arranged in available space on the base 114 of the cavity 104 that is spaced apart from one or more slot 109 that is formed through the stem 101 to provide access beyond the proximal portion during a surgical procedure. such as to allow insertion of an osteotome.

[0044] As shown in FIG. 3, in some examples, the one or more recess 121 is provided as an arrangement of slots that are recessed into the projection. In other examples, the one or more recess 121 can have a shape that substantially corresponds to a shape of the associated protrusions. In some examples, providing the one or more recess 121 as an arrangement of slots can exhibit improved surface contact with the sides of the one or more protrusion 111. In any configuration, mating of the one or more recess 121 and the one or more protrusion 111 can be configured to prevent rotation of the spacer 120 once it is positioned on the stem 101. Although the examples shown and described herein include the one or more protrusion 111 being provided on the stem 101 and the corresponding one or more recess 121 being provided on the liner 120, those having ordinary skill in the art will recognize that the reverse configuration is possible in which protrusions are formed on the liner 120 and are configured to be received in recesses formed in the stem 101. Those having ordinary skill in the art will recognize, however, that arranging protrusions on the liner 120 may not provide the same resistance to rotation that is possible where the protrusions are formed on the stem 101 due to the difference in material composition of the different components.

[0045] Referring to FIG. 5, in some examples, the one or more protrusion 111 has a tapered shape along its height. In particular, each of the one or more protrusion 111 can be designed to have a first width tl at or near its interface with the base 114 of the stem 101 and a second width t2 at its free end that extends away from the base 114, where the first width tl is greater than the second width t2. In this configuration, the one or more recess 121 formed in the liner 120 can have a width that is greater than the second width t2 but less than or equal to the first width tl. Alternatively, each of the one or more protrusion 111 can have a substantially constant width, but the width of each of the one or more recess 121 can be tapered such that the opening of each recess 121 is relatively wider than the protrusion 111 and tapers toward a relatively narrow width at the base of the recess 121. In some examples, protrusions having a desired tapered shape can be more readily verified (e.g., using a coordinate-measuring machine (CMM)) than tapered recesses.

[0046] In either configuration, the added tolerance provided by the relatively narrow free end of each of the one or more protrusion 111 can facilitate insertion of the one or more protrusion 111 into the one or more recess 121. In addition, the insertion of the one or more protrusion 111 into the corresponding one or more recess 121 can provide tactile feedback of progressive tightening, which can allow the user to recognize that proper alignment has been achieved prior to complete insertion/fixation. Full insertion can then result in a press-fit/interference-fit arrangement of the relatively wide base of the one or more protrusion 111 being secured within the one or more recess 121. In this way, the tapered shape of the one or more protrusion 111 can help secure the liner 120 into place, acting as fingers/anchors to reduce micromotion in each localized area and limit rotation of the liner 120 with respect to the stem 101.

[0047] In addition, in some examples, the projection 126 of the liner 120 can be configured to include a flange 127 that extends radially outward relative to adjacent portions of the projection 126 and is configured to fit within an undercut 107 formed beneath the edge 106, such as is shown in FIG. 4. In this configuration, insertion of the projection 126 of the liner 120 into the cavity 104 can proceed until the flange 127 of the projection 126 passes beyond the edge 106 and is received within the undercut 107. Removal of the liner 120 from this position can thus be resisted by the engagement of the flange 127 with an underside of the edge 106 within the undercut 107. To enable this engagement, in some examples, the material composition of the liner 120 and/or the shape and configuration of the flange 127 can be designed to be resiliently deformable. In this way the flange 127 can be compressed radially inwardly when the protrusion is inserted to allow the flange 127 to pass beyond the edge 106, but the flange 127 can return to its original shape once aligned with the undercut 107.

[0048] In addition, in some examples, the tapered shape of the one or more protrusion 111 relative to the one or more recess 121 and the mismatch between the width of the one or more recess 121 and the first width of the one or more protrusion 111 can cause an upward force to be exerted on the liner 120 as the one or more protrusion 111 resists being fully inserted into an interference fit with the one or more recess 121. This lifting action can urge the flange 127 of the projection 126 towards the edge 106 of the stem 101 such that the flange 127 engages the lower surface of the edge 106 within the undercut 107. In some examples, the position of the projection 126 relative to the depth of the cavity⁷ 104 at which the width of the one or more recess 121 is substantially equal to the width of the one or more protrusion 111 can substantially correspond to the depth at which the flange 127 is aligned with the undercut 107.

[0049] In another feature of the present disclosure, in place of the one or more protrusion 111, the system 100 can include a continuous or substantially continuous extruded ring 113 positioned around the center of the base 114 (e.g., surrounding the well 108) as shown in FIGS. 6 and 7. In such a configuration, the ring 113 can be configured to be coupled with a corresponding ring-shaped recess 123 formed within the projection 126 of the liner 120. [0050] Similarly, to the one or more protrusion 111, in some examples, the ring 113 has a tapered shape along its height. In particular, the ring 113 can be designed to have a first width tl’ at or near its interface with the base 114 of the stem 101 and a second width t2’ at its free end that extends away from the base 114. where the first width tl’ is greater than the second width t2’. In this configuration, the ring-shaped recess 123 formed in the liner 120 can have a width that is greater than the second width t2’ but less than or equal to the first width tl’. Alternatively, those having ordinary skill in the art will recognize that the ring 113 can have a substantially constant width, but the width of the ring-shaped recess 123 can be tapered such that the opening of the ringshaped recess 123 is relatively wider than the proximal portion of the ring 113 and tapers toward a relatively narrow' width at the base of the ring-shaped recess 123.

[0051] In either configuration, the tapered w idth of one of the ring 113 or the ringshaped recess 123 can help secure the liner 120 into place, reducing micromotion of the liner 120 with respect to the stem 101. Compared to the configuration disclosed above with respect to FIGS. 3-5, the ring 113 can provide increased surface area of contact relative to one or more protrusions 111. In some examples, the extrusion of the ring 113 can also be easier to manufacture than one or more protrusions 111. That being said, the ring 113 cannot limit rotation of the liner 120 with respect to the stem 101 in the same way as the one or more protrusions 111 since the liner 120 need not clocked to a specific rotational position to align with the stem 101, although the circumferential engagement of the ring 113 with the ring-shaped cavity 123 can provide some resistance to rotation due to the frictional engagement/interference-fit of the elements.

[0052] In any configuration, as discussed above, the disclosed system 100 can be used to improve a reverse shoulder implant configuration in which the liner 120 includes a concave articular surface such as is shown in FIG. 8A. which can be configured to engage the metal spherical head coupled to the glenoid. Alternatively, as shown in FIG. 8B. the configuration of stem 101 disclosed herein can be adapted for use in an anatomic shoulder implant in which the stem 101 is coupled to a spherical humeral head 130.

[0053] In accordance with one or more further features of the present disclosure, in some instances, liner removal can be anecessary step to either replace the liner (e g., to change the lateral offset with a different liner height) ), to add a spacer, to add a humeral head (if switching from an anatomic to reverse), and/or to replace the stem (which can require liner removal to attach the stem removal tool to the stem implant). It is important that during liner removal procedure, the stem (including its internal features, such as the morse taper, that interact with the humeral head 130 (as shown in FIG. 8B), as well as with the liner when the liner is positioned on the stem and/or features that mate with the spacer, humeral head, and/or stem removal tool) does not become damaged as such damage may cause instability and/or improper setting of the new liner/spacer/humeral head/stem, and/or cause improper positioning and/or movement of the humeral head once it is positioned into the stem. The current subject matter process for removal of the liner is advantageous in that it effectively removes the liner from the stem while protecting its internal features.

[0054] FIGS. 9A-10B illustrate an example process for removal of a liner from the stem, according to some examples of the current subject matter. FIGS. 9A and 9B illustrate perspective views of the liner and the stem. FIGS. 10A and 10B illustrate cross-sectional views of the liner and the stem during liner removal. [0055] As shown in FIG. 9A, a stem 301 is coupled to the liner 320. where the liner

320 is to be removed from the stem 301. To remove the liner 320, an osteotomy sizer 306 may be positioned onto the liner 320. The osteotomy sizer 306 may be selected in a way to best approximate the outer diameter of the liner 320. Alternatively, or in addition, the osteotomy sizer 306 may be selected to approximately match the outer circumference of the liner 320. This way, the center 308 of the sizer 306 may be arranged and configured with the center of the liner 320 and thus, be aligned with the well (e.g., corresponding to the well 108 of the stem 101 as shown in FIGS. 2 and 3) of the stem 301. As can be understood, any size of the osteotomy sizer 306 may be selected as long as the above alignment of the sizer, the liner and the stem’s well is preserved. [0056] Once osteotomy sizer 306 is positioned on the liner 320, a glenoid guide pin 310 (as shown in FIG. 9A) and/or a driver 312 (as shown in FIG. 9B) may be used to drill through the center 308 of the sizer 306 and, thus, the center of the liner 320. This creates a through opening in the liner 320. Alternatively, a drill with a drill bit (not shown in FIGS. 9A-B) may be used to create such opening in the liner 320. The glenoid guide pin 310, driver 312, and/or the drill bit may have a diameter that is smaller than the internal diameter of the well of the liner 320. Such a relatively smaller diameter of the glenoid guide pin 310, driver 312 and/or the drill bit prevents the pin 310, driver 312 and/or the drill bit from contacting the well w alls of the stem and, thus, damaging the interior of the stem’s cavity during drilling. While damage to the bottom of the well of the liner’s cavity may occur, such damage does not affect other interior surfaces of the cavity of the stem 301, thereby allowing secure positioning of a new liner/spacer/humeral head/stem removal tool. In some examples, a 2.5 mm diameter glenoid guide pin 310 (and/or driver 312) and/or a 3 mm diameter drill bit may be used. As can be understood, any other diameters of the guide pin 310 and/or the drill bit may be used.

[0057] In some examples, the glenoid guide pin 310, the driver 312 (that may mate with a screw as shown in FIGS. 10A-B) may be used first to create a pilot opening in the liner 320. Once the pilot opening is made, a larger drill bit (e.g., 3mm) may be used to create a through opening in the liner 320. As can be understood, any other way of creating the opening in the liner 320 may be used.

[0058] As shown in FIGS. 10A-B, after the through opening is created in the liner 320, one or more screws 402 may be threaded through the opening. As shown in FIG. 10A, the screw 402 may be positioned on a top surface of the created opening 412 in the liner 320. Once positioned, the screw 402 may be threaded through the opening 412 until it reaches a bottom surface of the well 408 (e.g., a morse taper) of the stem 301. The screw⁷402 may continue to be threaded through the opening 412 until the liner 320 is forced from the stem 301. In particular, the bottom of the well 408 creates a stop surface for the screw 402 and applies a counterforce to the screw 412, thereby causing the threads of the screw⁷ 402 positioned in the liner 320 to apply a force (in a direction away from the interior cavity 406 and the well 408 of the stem 301) to the liner 320 to push and release it from the stem 301, as shown in FIG. 10B. Once the liner 320 is released from the stem 301, it, along with a screw⁷402, may be discarded.

[0059] The screw 402 may have a diameter that is smaller than the interior diameter of the well 408 of the stem 301. This will avoid damage to the interior surfaces of the cavity 406 and the w ell 408 (except the bottom surface of the w ell). Further, the screws 402 may have a length that may be longer than the depth of the entire cavity 406 (including the depth of the well 408). In some examples, the screw- may be 30 mm long. The diameter of the screw may be slightly larger than the opening 412. For example. the screw 402 may have a 4.5 mm diameter. As can be understood, any other dimensions for the screw 402 may be used.

[0060] FIG. 11 illustrates an example process 500 for removal of a liner from a stem of an implant, according to some examples of the current subject matter. The process 500 may be performed to remove the liner 320 from the stem 320 (as shown in FIGS. 9A-10B). In a sizing step 502, an osteotomy sizer that approximates the diameter of the liner 320 may be selected. For example, sizer 306, as shown in FIG. 9A, can be selected. During a surgical implantation procedure, the surgeon (and/or any other medical professional) may have a variety of sizers 306 available to them. If one sizer does not best approximate the liner 320, another sizer 306 may be selected and positioned on the liner to determine whether or not it is a proper fit. Once the sizer 306 is selected, the sizer may be centrally positioned on the top surface of the liner 320, e.g., as shown in FIG. 9A.

[0061] In an opening step 504, while centrally holding the osteotomy sizer 306 on the liner 320, an opening in the liner 320 may be drilled through the center of the osteotomy sizer 306. For example, the glenoid guide pin 310 and/or a drill bit (using a drill) may be used to create an opening through the liner 320. As stated above, the pin 310 and/or the drill bit may be selected to be smaller than an interior diameter of the well 408 of the stem 301 (as shown in FIGS. 9A-10B). Alternatively, or in addition, the opening may be created in two stages: first, a pilot opening may be created using the glenoid guide pin, and second, a through opening may be created using a drill bit that may have a larger diameter than the guide pin. As can be understood, any other way of creating an opening in the liner 320 may be used. [0062] Once the opening is created, a screw may be positioned into the drilled opening. For example, as shown in FIG. 10A, screw 402 may be positioned into the opening 412 of the liner 320, in a positioning step 506. Then, the screw may be threaded through the opening until it contacts a bottom of the stem' s well. Threading of the screw 402 through the liner 320 may continue until the tip of the screw 402 reaches the bottom of the well 408 of the stem 301.

[0063] In a threading step 508, threading of the screw through the opening may continue until the liner disengages from the stem. As discussed above, threading of the screw 402 may cause the screw 402 to push up against the bottom of the well 408. Continuous threading of the screw may generate a pushing force that translates along the screw’s length to cause the screw’s threads engaged in the liner 320 to push on the liner 320 and release it from the stem’s cavity 406, as shown in FIG. 10B. Once the liner 320 is released from the stem, the liner and the screw may be removed in a removal step 510.

[0064] While the present disclosure refers to certain examples, numerous modifications, alterations, and changes to the described examples are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described examples, but that it has the full scope defined by the language of the following claims, and equivalents thereof. The discussion of any example is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples. In other words, while illustrative examples of the disclosure have been described in detail herein, it is to be understood that the inventive concepts can be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.

[0065] The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more examples or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain examples or configurations of the disclosure can be combined in alternate examples, or configurations. Any example or feature of any section, portion, or any other component shown or particularly described in relation to various examples of similar sections, portions, or components herein can be interchangeably applied to any other similar example or feature shown or described herein. Additionally, components with the same name can be the same or different, and one of ordinary skill in the art would understand each component could be modified in a similar fashion or substituted to perform the same function.

[0066] Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate example of the present disclosure.

[0067] As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one example” of the present disclosure are not intended to be interpreted as excluding the existence of additional examples that also incorporate the recited features. [0068] The phrases “at least one,” “one or more,” and “and/or” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. The terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. All directional references (e.g.. proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of this disclosure. Connection references (e.g., engaged, attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative to movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. All rotational references describe relative movement between the various elements. Identification references (e.g., primary', secondary', first, second, third, fourth, etc.) are not intended to connote importance or priority' but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative to sizes reflected in the drawings attached hereto can vary.

Claims

CLAIMS We claim:

1. A system for shoulder arthroplasty, the system comprising: a stem including a proximal portion, a distal portion, and a body disposed between the proximal portion and the distal portion, wherein the proximal portion comprises a cavity extending toward the body; and a liner configured for coupling within the cavity of the stem; wherein one of the stem or the liner comprises one or more protrusion extending from a surface thereof, wherein each of the one or more protrusion has a profile that tapers from a first width at the base to a second width that is narrower that the first width; wherein an other of the stem or the liner comprises one or more recess, each of the one or more recess being configured to receive therein one of the one or more protrusion, each of the one or more recesses having a width that is narrower than the first width and wider than the second width.

2. The system of claim 1, wherein the liner comprises a concave articular surface configured for use in a reverse shoulder implant.

3. The system of claim 1, wherein the liner comprises a base of a substantially spherical head configured for use in an anatomic shoulder implant.

4. The system of claim 1, wherein the cavity comprises one or more edge defining an outer wall of the cavity; wherein the liner comprises a projection; and wherein the projection is configured to engage the one or more edge.

5. The system of claim 4, wherein a diameter of the projection is greater than a diameter of the cavity such that the projection is configured to engage the one or more edge in a friction-fit arrangement.

6. The system of claim 4, wherein the cavity comprises an undercut extending radially outward beneath the one or more edge; wherein the projection comprises a flange that extends radially outward from the projection; and wherein, when the projection is coupled within the cavity, the flange is configured to pass beneath the one or more edge and into the undercut.

7. The system of claim 1, wherein the stem comprises one or more slot formed through the base of the recess; and wherein the one or more protrusion is spaced apart from the one or more slot on the base of the recess.

8. The system of claim 1, wherein the one or more protrusion comprises a ring; and wherein the one or more recess comprises a ring-shaped recess.

9. The system of claim 8, wherein the ring comprises a substantially continuous ring.

10. A method for shoulder arthroplasty’, the method comprising: inserting a stem into a patient’s humerus during a surgical procedure, the stem including a proximal portion, a distal portion, and a body disposed between the proximal portion and the distal portion, wherein the proximal portion comprises a cavity extending toward the body; and coupling a liner to the proximal portion of the stem by inserting a portion of the liner within the cavity of the stem; wherein one of the stem or the liner comprises one or more protrusion extending from a surface thereof, wherein each of the one or more protrusion has a profile that tapers from a first width at the base to a second width that is narrower that the first width; wherein an other of the stem or the liner comprises one or more recess, each of the one or more recess being configured to receive therein one of the one or more protrusion, each of the one or more recesses having a width that is narrower than the first width and wider than the second width; and wherein coupling the liner to the proximal portion of the stem comprises coupling each of the one or more recess with one of the one or more protrusion.

11. The method of claim 10, wherein the liner comprises a concave articular surface configured for use in a reverse shoulder implant.

12. The method of claim 10. wherein the liner comprises a base of a substantially spherical head configured for use in an anatomic shoulder implant.

13. The method of claim 10, wherein the cavity comprises one or more edge defining an outer wall of the canty; wherein the liner comprises a projection; and wherein coupling the liner to the proximal portion of the stem comprises engaging the projection with the one or more edge.

14. The method of claim 13, wherein a diameter of the projection is greater than a diameter of the cavity such that the projection engages the one or more edge in a friction-fit arrangement.

15. The method of claim 13, wherein the cavity comprises an undercut extending radially outward beneath the one or more edge; wherein the projection comprises a flange that extends radially outward from the projection; and wherein coupling the liner to the proximal portion of the stem comprises passing the flange beneath the one or more edge and into the undercut.

1 . The method of claim 10, wherein the stem comprises one or more slot formed through the base of the recess; and wherein the one or more protrusion is spaced apart from the one or more slot on the base of the recess.

17. The method of claim 10. wherein the one or more protrusion comprises a ring; and wherein the one or more recess comprises a ring-shaped recess.

18. The method of claim 17, wherein the ring comprises a substantially continuous ring.