Stemless implant system for arthroplasty

Abstract

An arthroplasty implant system and method for restoring function to a joint is provided. The arthroplasty implant system may include a threaded cup having a cylindrical body and a flange. A screw thread may be provided on the cylindrical body. The screw thread is configured to engage bone and the flange is configured to engage a cortical rim of the bone.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 278,226, filed November 11, 2021, and is incorporated herein by reference in its entirety. [Background technology]

[0002] The present disclosure relates to the field of joint arthroplasty, and more particularly to an arthroplasty implant system including an implant capable of forming a stemless convertible platform for coupling with a joint implant.

[0003] Many bones in the human musculoskeletal system contain articular surfaces that work together to facilitate different types and degrees of joint movement. Over time, through repeated use or wear, articular surfaces can erode or experience bone loss, which can cause joint instability and pain.

[0004] Joint arthroplasty is an orthopedic surgical procedure performed to repair or replace joints that exhibit degenerative bone defects. Bone defects can occur along the articular surface of a bone. Some joint arthroplasty procedures utilize one or more implants to repair the articular surface. Summary of the Invention [Means for solving the problem]

[0005] The present disclosure relates to arthroplasty implant systems and methods designed to restore joint function. The arthroplasty implant system may include an implant assembly including a convertible stemless implant.

[0006] An exemplary humeral implant assembly for an arthroplasty implant system may include, among other things, an articular implant and a stemless implant adapted to form a convertible platform for receiving the articular implant. The stemless implant includes threads configured to engage the cortical and / or cancellous bone of the bone and a flange sized to engage the cortical rim of the bone.

[0007] In a further embodiment, the joint implant is an anatomical joint implant that includes a convex articular surface.

[0008] In a further embodiment, the joint implant is a reverse joint implant that includes a concave articular surface.

[0009] In a further embodiment, the joint implant includes a spacer coupled to the stemless implant and a liner coupled to the spacer, the liner including a concave articular surface.

[0010] In a further embodiment, the spacer is coupled to the stemless implant by a C-ring.

[0011] In a further embodiment, the stemless implant is constructed from a polyetheretherketone (PEEK) material.

[0012] In a further embodiment, the stemless implant includes a receiving cavity adapted to receive the joint implant, the receiving cavity extending inwardly from the flange to the floor of the rounded base of the stemless implant.

[0013] In a further embodiment, the floor forms the inner surface of the rounded base.

[0014] In a further embodiment, the threads are circumferentially disposed around the radially outer surface of the cylindrical body of the stemless implant.

[0015] In a further embodiment, the outer diameter of the flange is greater than the outer diameter of the cylindrical body at the tip of the threads.

[0016] In a further embodiment, the cylindrical body includes a plurality of pockets adapted to promote bone ingrowth.

[0017] In a further embodiment, the flange includes a plurality of suture eyelets each configured to receive a thread-like material.

[0018] An exemplary arthroplasty implant system may include, among other things, a threaded cup having a cylindrical body and a flange. Threads may be provided on the cylindrical body. The threads are configured to engage the cortical and / or cancellous bone of the bone, and the flange is sized to engage the cortical rim of the bone.

[0019] In a further embodiment, the flange is integrally formed with the cylindrical body, establishing a one-piece, single-piece design for the threaded cup.

[0020] In a further embodiment, the threaded cup incorporates an inlay design that establishes a convertible platform for receiving a joint implant.

[0021] In a further embodiment, the joint implant includes a spacer coupled to the threaded cup by a C-clip and a liner coupled to the spacer.

[0022] In a further embodiment, the flange is provided on a first side of the cylindrical body and the rounded base is provided on a second side of the cylindrical body.

[0023] In a further embodiment, the receiving cavity extends inwardly from the flange to a floor of the rounded base, which in turn forms the inner surface of the rounded base.

[0024] In a further embodiment, the at least one engagement opening is formed through a rounded base of the threaded cup.

[0025] In a further embodiment, the rounded base comprises a trap door.

[0026] In a further embodiment, the outer diameter of the flange is greater than the outer diameter of the cylindrical body at the tip of the threads.

[0027] In a further embodiment, the cylindrical body includes a plurality of pockets adapted to promote bone ingrowth.

[0028] In a further embodiment, the flange includes a plurality of suture eyelets each configured to receive a thread-like material. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 shows a humeral implant assembly of an arthroplasty implant system. [Figure 2] FIG. 2 illustrates another exemplary humeral implant assembly of an arthroplasty implant system. [Figure 3] FIG. 3 shows an exemplary threaded cup of a humeral implant assembly. [Figure 4] 4 is a top perspective view of the threaded cup of FIG. 3. FIG. [Figure 5] FIG. 5 is a side perspective view of the threaded cup of FIG. 3. [Figure 6] FIG. 6 illustrates the flange of the threaded cup of FIG. 3 engaging the cortical rim of bone. [Figure 7] FIG. 7 illustrates various details associated with the circumferential threads of the threaded cup of FIGS. [Figure 8] FIG. 8 illustrates another exemplary threaded cup of a humeral implant assembly. [Figure 9] FIG. 9 illustrates a modular stem that can be used with the threaded cup of FIG. [Figure 10] FIG. 10 illustrates a humeral implant assembly including a threaded cup. [Figure 11] FIG. 11 shows an exploded view of the humeral implant assembly of FIG. [Figure 12] 12 is a cross-sectional view of the humeral implant assembly of FIG. [Figure 13] 13A and 13B show a spacer of another exemplary humeral implant assembly. [Figure 14] FIG. 14 shows a liner of the humeral implant assembly of FIG. [Figure 15] FIG. 15 illustrates another exemplary liner for the humeral implant assembly of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present disclosure describes an arthroplasty implant system and method for restoring joint function. The arthroplasty implant system may include an implant capable of establishing a stemless convertible platform for coupling with a joint implant.

[0031] In some embodiments, the arthroplasty implant system of the present disclosure may include a threaded cup having a cylindrical body and a flange. Threads may be disposed on the cylindrical body. The threads are configured to engage the cortical and / or cancellous bone of the bone, and the flange is configured to engage the cortical rim of the bone. These and other features of the present disclosure are described in further detail below.

[0032] 1 illustrates an arthroplasty implant system 10 including a humeral implant assembly 12. The humeral implant assembly 12 can be implanted within the humerus 14 of a shoulder joint to help reconstruct the natural articular surface of the humerus 14 and / or restore function (e.g., range of motion, stability, etc.) of the shoulder joint. Although not shown, the arthroplasty implant system 10 may further include a glenoid implant assembly configured to couple with the humeral implant assembly 12 to restore function to the shoulder joint. Additionally, although the teachings of the present disclosure are described with particular reference to the shoulder joint, the present disclosure is not intended to be limited to any particular joint of the human musculoskeletal system and may be applicable to other joints, such as, for example, the hip joint.

[0033] The humeral implant assembly 12 may include a threaded cup 16 and an anatomical glenoid implant 18A (see FIG. 1 ) or a reverse glenoid implant 18B (see FIG. 2 ). The anatomical glenoid implant 18A may be utilized in combination with the threaded cup 16 to perform an anatomical total shoulder arthroplasty procedure, and the reverse glenoid implant 18B may be utilized in combination with the threaded cup 16 to perform a reverse shoulder arthroplasty procedure. In a reverse shoulder arthroplasty procedure, the reconstructed humerus 14 provides the socket portion, and the glenoid cavity (not shown) provides the ball portion of a ball-and-socket joint, which is the reverse of the natural anatomy. The anatomical glenoid implant 18A may include a convex glenoid surface 20A, and the reverse glenoid implant 18B may include a concave glenoid surface 20B. The articular surfaces 20A, 20B are configured to interface with the natural glenoid cavity or the glenoid implant assembly of the arthroplasty implant system 10.

[0034] In some implementations, the threaded cup 16, the anatomical joint implant 18A, and the reverse joint implant 18B may be provided together as part of a surgical kit, which may further include multiple sizes of each of the threaded cup 16, the anatomical joint implant 18A, and the reverse joint implant 18B.

[0035] In the illustrated embodiment, the humeral head of the humerus 14 has been resected, thus removing the natural glenoid components of the humerus 14 to prepare the humerus 14 for receiving the humeral implant assembly 12. After the humerus 14 has been properly prepared, the threaded cup 16 can be threaded into the metaphysis 22 of the humerus 14. In one embodiment, the threaded cup 16 is a stemless implant for the humeral implant assembly 12, and therefore, there is no stem extending into the diaphysis 24 of the humerus 14. The threaded cup 16 may be configured to establish a convertible platform for receiving either an anatomical glenoid implant 18A or a reverse glenoid implant 18B. The anatomical glenoid implant 18A or the reverse glenoid implant 18B may be attached to the threaded cup 16 to assemble the humeral implant assembly 12.

[0036] The threaded cup 16 of the humeral implant assembly 12 is further illustrated in Figures 3, 4, and 5 (with continued reference to Figures 1 and 2). In one embodiment, the threaded cup 16 is constructed of a titanium material. In another embodiment, the threaded cup 16 may be made of a material having a modulus of elasticity relatively close to that of cortical bone, such as, for example, polyetheretherketone (PEEK). Alternatively, other materials for constructing the threaded cup 16 may be utilized within the scope of the present disclosure.

[0037] The threaded cup 16 may include a cylindrical body 26 extending between a flange 28 located at the top or proximal side of the threaded cup 16 and a rounded base 30 located at the bottom or distal side of the threaded cup 16. In this embodiment, the threaded cup 16 embodies a one-piece, single-piece design in which the flange 28 is integrally formed with the cylindrical body 26.

[0038] The receiving cavity 32 of the threaded cup 16 may be configured to receive and secure either an anatomical joint implant 18A or a reverse joint implant 18B to the threaded cup 16. The receiving cavity 32 may be surrounded by a flange 28 and a cylindrical body 26. The receiving cavity 32 may extend inward from the flange 28 to a floor 34 of a rounded base 30. The floor 34 may form the inner surface of the rounded base 30.

[0039] The receiving cavity 32 can provide an inlay design in which the majority of the threaded cup 16 (except for the flange 28) is positioned medially on the humerus 14. In this manner, the connection between the threaded cup 16 and the joint implants 18A, 18B is also inlayed rather than exhibiting an onlay design.

[0040] The threads 36 may be circumferentially disposed about a radially outer surface 38 of the cylindrical body 26. The threads 36 may be self-tapping threads configured to allow the threaded cup 16 to be screwed into the humerus 14. The threads 36 may be configured such that either a clockwise or counterclockwise rotation functions to advance the threaded cup 16 into the humerus 14.

[0041] In one embodiment, the outer diameter D1 of the flange 28 is larger than the outer diameter D2 of the cylindrical body 26 (here defined at the tip of the threads 36) (see, e.g., FIG. 5). The outer diameter D1 of the flange 28 may be sized to allow the flange 28 to engage with the cortical rim 40 of the humerus 14 (see, e.g., FIG. 6). Such engagement of the cortical rim 40 may provide additional fixation support and better load the proximal portion of the humerus 14.

[0042] Additionally, the outer diameter D2 may be sized such that, when the threaded cup 16 is inserted therein, the threads 36 are positioned relatively close to the cortical bone 42 of the humerus 14 (see, e.g., FIG. 6 ). Securing the threaded cup 16 with the threads 36 as close as possible to the cortical bone 42 may provide improved initial and long-term fixation compared to “press-fit” implant designs. Thus, the threads 36 may engage the cortical bone 42, the cancellous bone 43, or both.

[0043] Cylindrical body 26 may further include an inner diameter D3. Inner diameter D3 may establish the cup size of threaded cup 16. Inner diameter D3 may be smaller than both outer diameter D1 and outer diameter D2.

[0044] The actual dimensions of the outer diameter D1 of the flange 28, the outer diameter D2 of the cylindrical body 26, and the inner diameter D3 of the cylindrical body 26 may vary depending on, among other factors, the size of the patient. The above-referenced surgical kit may include threaded cups having multiple combinations of flange 28 outer diameter sizes and cylindrical body 26 inner diameter sizes. Table 1 below shows exemplary sizes of threaded cups 16 that may be provided as part of the surgical kit. The listed sizes are intended to be exemplary only and therefore non-limiting. [Table 1]

[0045] The flange 28 of the threaded cup 16 may be either circular or oval, however, the actual shape of the flange 28 is not intended to limit the present disclosure.

[0046] A plurality of suture eyelets 44 may extend through the flange 28. The suture eyelets 44 may be configured to receive a thread-like material, such as a suture 46 (see FIG. 3). The suture 46 may then be utilized to assist in fastening tissue (e.g., subscapularis, supraspinatus, etc.) to the humerus 14 in the area around the flange 28.

[0047] One or more notches or interruptions 48 may be formed in the flange 28 / cylindrical body 26 of the threaded cup 16. The interruptions 48 are sized to receive the mating features of a wedge / spacer (not shown) that may be utilized in combination with the threaded cup 16 to reduce loosening between the threaded cup 16 and the joint implants 18A, 18B. The mating features of the wedge / spacer may engage the walls of the flange 28 that define the interruptions 48 to prevent rotation of the wedge / spacer relative to the threaded cup 16.

[0048] One or more engagement openings 50 may be formed through the rounded base 30 of the threaded cup 16. The engagement openings 50 may be configured to receive additional mating features of the wedge / spacer. The engagement openings 50 may be, for example, threaded circular openings.

[0049] The rounded base 30 may include one or more additional engagement openings 52 formed therethrough. The engagement openings 52 may be configured to receive mating features of an inserter device that may be utilized to implant the threaded cup 16 within the humerus 14. The engagement openings 52 may be oval or circular, for example.

[0050] The threaded cup 16 may further include a plurality of pockets 54. The pockets 54 may be formed in the radially outer surface 38 of the cylindrical body 26 just inward of the flange 28. The pockets 54 may promote bone ingrowth after insertion. Alternatively, or additionally, a porous coating may be applied to selected portions of the cylindrical body 26 to promote bone ingrowth. In yet another embodiment, the surface finish of the threads 36 may be grit blasted to promote bone ingrowth. In one embodiment, the pockets 54 may be oval.

[0051] 7 illustrates additional details related to the threads 36 of the threaded cup 16. The threads 36 may include design characteristics such as a thread pitch 60, a thread angle 62, a thread tip width 64, a thread root width 66, a thread depth 68, and a thread root radius 70. Table 2 below shows exemplary design characteristics of the threads 36. The disclosed characteristics are for illustrative purposes only; thus, other specific thread configurations are intended to be within the scope of this disclosure. In this disclosure, the term "about" means that the expressed quantity or range need not be exact and may be approximate and / or larger or smaller, reflecting acceptable tolerances, conversion factors, measurement errors, etc. [Table 2]

[0052] The pitch 60 of the threads may be variable. In one embodiment, the variable pitch increases in a direction extending from the proximal side of the threaded cup 16 toward the distal side of the threaded cup 16. In another embodiment, the variable pitch increases in a direction extending from the distal side of the threaded cup toward the proximal side of the threaded cup 16.

[0053] The threads 36 may be single, double, or triple start threads. The thread lead may be modified to control the amount of turns it takes to seat the threaded cup 16 in the bone.

[0054] The threaded cup 16 may be implanted into the humerus 14 during a shoulder arthroplasty procedure. The shoulder arthroplasty procedure may include at least the following steps: (1) preparing the humerus 14 to receive the threaded cup 16 (e.g., resecting the humeral head, preparing a cavity in the resected humerus, etc.), (2) threading the threaded cup 16 into the prepared humerus, and (3) connecting the joint implants 18A, 18B to the implanted threaded cup 16. More or fewer steps may be performed as part of the shoulder arthroplasty procedure within the scope of the present disclosure. Once implanted, the threads 36 of the threaded cup 16 may engage the humerus 14 near the cortical bone 42, and the flange 28 may load against the cortical rim 40. Thus, the threads 36 may engage the cortical bone 42, the cancellous bone 43, or both.

[0055] 8 and 9 illustrate another exemplary threaded cup 116 for a humeral implant assembly of an arthroplasty implant system. The threaded cup 116 is similar to the threaded cup 16 described above. However, in this embodiment, the threaded cup 116 may include a trap door 72 that may be movably or removably connected to the rounded base 30 of the threaded cup 116. The trap door 72 may be moved relative to the rounded base 30 or removed from the rounded base 30 to expose an opening 74 therethrough. Another implant, such as a stem 76 (see, for example, FIG. 9 ), may be inserted through the opening 74 and connected to the threaded cup 116 when the trap door 72 is moved or removed to improve the torsional stability of the threaded cup 116.

[0056] 10, 11, and 12, the threaded cup 16 (or threaded cup 116) may be utilized as part of a humeral implant assembly 99 of an arthroplasty implant system. In addition to the threaded cup 16, the humeral implant assembly 99 may include a spacer 78 and a liner 80. The spacer 78 and liner 80 may collectively form the glenoid implant 82 of the humeral implant assembly 99.

[0057] In this embodiment, the joint implant 82 is a reverse-type joint implant. Thus, the liner 80 may include a concave articular surface 84. However, anatomical joint implants are also contemplated within the scope of the present disclosure (see, e.g., FIG. 1).

[0058] The threaded cup 16 may include one or more engagement openings 91 formed in the rounded base 30. The engagement openings 91 may receive anti-rotation pegs 93 on the spacer 78 (or the liner 80 if no spacer 78 is used) to stabilize the rotation of the spacer 78 relative to the threaded cup 16.

[0059] C-clips 86 may be used to couple spacer 78 to threaded cup 16, and liner 80 may be coupled to spacer 78 by a tapered connection or any other connection. C-clips 86 may be received within circumferential grooves 88 formed within receiving cavity 32 of threaded cup 16, and C-clips 86 may further be received within circumferential grooves 90 formed within spacer 78.

[0060] In one embodiment, liner 80 includes a locking block 92. Locking block 92 may be received within a notch 94 formed in spacer 78. Locking block 92 may be configured to prevent C-clip 86 from deforming inwardly and allow spacer 78 to disengage from threaded cup 16.

[0061] In another embodiment, the locking block 92 is provided by the spacer 78 (see, e.g., FIGS. 13A and 13B). In this embodiment, the locking block 92 is translatable between an open position (FIG. 13A), in which the C-clip 86 is free to deform, and a locked position (FIG. 13B), in which the C-clip 86 is prevented from deforming. The locking block 92 is movable from the open position to the locked position in response to the force applied by the liner 80 as the liner moves into interlocking engagement with the spacer 78.

[0062] In other implementations, the spacer 78 may be secured to the threaded cup 16 via a tapered connection. In still other embodiments, the spacer 78 may be removed from the humeral implant assembly 99, and the liner 80 may be secured directly to the threaded cup 16, for example, via either a tapered connection or a C-clip. Accordingly, the present disclosure is not intended to be limited to the exact embodiments shown in FIGS. 10-13B.

[0063] In one embodiment, the liner 80 is a metal component (see FIG. 14). In another embodiment, the liner 80 may include both a metal portion 96 and a polymer portion 98 (see FIG. 15). The polymer portion 98 may form the concave articular surface 84 of the joint implant 82 and may be insert molded into the shell provided by the metal portion 96.

[0064] An exemplary arthroplasty implant system of the present disclosure employs a stemless implant capable of establishing a convertible platform for coupling with a joint implant. The stemless implant may be configured as a threaded cup incorporating a flange (e.g., a circumferential ring / trunnion) adapted to rest on the cortical rim of the resected bone to provide additional fixation support and more advantageously load the bone during implantation. The stemless implant may further provide an inlay design that allows for the construction of an inlay-type reverse prosthesis.

[0065] Although different non-limiting embodiments are illustrated as having particular components or steps, embodiments of the present disclosure are not limited to those particular combinations. Some of the components or features from any of the non-limiting embodiments can be used in combination with features or components from any of the other non-limiting embodiments.

[0066] It will be understood that like reference numerals identify corresponding or similar elements throughout the several views. It will further be understood that, while particular component arrangements are disclosed and illustrated in these exemplary embodiments, other arrangements can also benefit from the teachings of the present disclosure.

[0067] The foregoing description should be construed as illustrative and not in any limiting sense. Those skilled in the art will understand that certain modifications may fall within the scope of the present disclosure. For these reasons, the following claims should be studied to determine the true scope and content of the present disclosure. [Explanation of symbols]

[0068] 10 Arthroplasty Implant Systems 12 Humeral Implant Assembly 14 Humerus 16 Threaded Cup 18A Anatomical Joint Implants 18B Reverse joint implant 20A Articular Surface 20B Articular surface 22 Metaphysis 24 Bones 26 Main Unit 28 flange 30 base 32 Receptive Cavity 34 Floor 36 threads 38 Radial outer surface 40 Cortical Rim 42 Cortical bone 43 Cancellous bone 44 Suture Eyelet 46 Sutures 48 Interruption 50 engagement opening 52 engagement opening 54 pockets 60 thread pitch 62 Thread angle 64 thread tip width 66 Width of the screw base 68 thread depth 70 Thread root radius 72 Trapdoor 74 Opening 76 Stem 78 Spacer 80 Liner 82 Joint Implants 84 Articular Surface 86 C-clip 88 Circumferential groove 90 Circumferential groove 91 Engagement opening 92 Rock Block 93 Anti-rotation peg 94 notches 96 Metal parts 98 Polymer part 99 Humeral Implant Assembly 116 Threaded Cup D1 Outer diameter D2 outer diameter D3 inner diameter

Claims

1. 1. A humeral implant assembly for an arthroplasty implant system, comprising: joint implants and a stemless implant adapted to form a convertible platform for receiving said joint implant; the stemless implant including threads configured to engage bone and a flange sized to engage a cortical rim of the bone; An assembly wherein the stemless implant includes a receiving cavity adapted to receive the joint implant, and further wherein the receiving cavity extends inward from the flange to a floor of a rounded base of the stemless implant, the floor forming an inner surface of the rounded base.

2. 2. The assembly of claim 1, wherein the joint implant comprises a spacer coupled to the stemless implant and a liner coupled to the spacer, the liner including a concave articular surface, and the spacer coupled to the stemless implant by a C-clip.

3. 3. The assembly of claim 1 or 2, wherein the stemless implant is constructed from a polyetheretherketone (PEEK) material.

4. The assembly of claim 1 , wherein the threads are disposed circumferentially around a radially outer surface of the cylindrical body of the stemless implant.

5. 5. The assembly of claim 4, wherein the flange has an outer diameter greater than the outer diameter of the cylindrical body at the tip of the threads, and the cylindrical body includes a plurality of pockets adapted to promote bone ingrowth.

6. The assembly of claim 1 , wherein the flange includes a plurality of suture eyelets each configured to receive a thread-like material.

7. 1. An arthroplasty implant system comprising: a threaded cup including a cylindrical body, a thread on the cylindrical body, and a flange; the threads are configured to engage bone and the flange is sized to engage a cortical rim of the bone; the flange is provided on a first side of the cylindrical body and a rounded base is provided on a second side of the cylindrical body; A receiving cavity extends inward from the flange to a floor of the rounded base, the floor forming an inner surface of the rounded base.

8. The arthroplasty implant system of claim 7 , wherein the flange is integrally formed with the cylindrical body to establish a one-piece, single-piece design of the threaded cup.

9. 9. The arthroplasty implant system of claim 7 or 8, wherein the threaded cup embodies an inlay design that establishes a convertible platform for receiving a joint implant, the joint implant including a spacer coupled to the threaded cup by a C-clip and a liner coupled to the spacer.

10. The arthroplasty implant system of claim 7 , comprising at least one engagement opening formed through said rounded base, said rounded base including a trap door.

11. The arthroplasty implant system of claim 7 , wherein the flange has an outer diameter greater than the cylindrical body outer diameter at the tip of the threads.

12. 8. The joint arthroplasty implant system of claim 7, wherein the cylindrical body includes a plurality of pockets adapted to promote bone ingrowth, and the flange includes a plurality of suture eyelets each configured to receive a thread-like material.

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