Hydrogel implant for the arch of the foot

Abstract

Disclosed is a novel implant for replacing a portion of an articular surface of a joint. The implant includes a bone-engaging surface, a hydrogel portion forming an articular surface opposite the first bone-engaging surface, and a bone plate portion configured to fix the implant to the bones forming the joint.

Description

Technical Field

[0001] The present disclosure generally relates to orthopedic implants, and more particularly, to a hydrogel implant for repairing the articular surface of a joint in the arch region of the foot. Background Art

[0002] Implants can be used to replace degenerated or otherwise damaged cartilage within a joint. Such devices can be used to treat osteoarthritis, rheumatoid arthritis, other inflammatory diseases, general joint pain, and joint injuries. Summary of the Invention

[0003] Disclosed herein is an implant for replacing a portion of the articular surface of a joint, the implant comprising: a main portion configured to be inserted into the joint, wherein the main portion comprises: a porous material portion having a first bone-engaging surface; and

[0004] a hydrogel portion bonded to the porous material portion and forming an articular surface opposite the first bone-engaging surface; and

[0005] a bone plate portion configured to fix the implant to the bones forming the joint;

[0006] wherein the main portion has a front end and a rear end, wherein the front end is configured to be inserted into the joint;

[0007] wherein the bone plate portion is integrally formed with the porous material portion and extends from the rear end, thereby forming a second bone-engaging surface, the second bone-engaging surface also being formed of porous material and extending from the first bone-engaging surface in a direction opposite to the articular surface at an angle with respect to the first bone-engaging surface;

[0008] wherein the bone plate portion includes a solid metal portion that forms all of the outer surfaces of the bone plate portion except for the second bone-engaging surface; and

[0009] wherein the bone plate portion has at least one screw hole for receiving a bone screw.

[0010] Disclosed is an implant for replacing a portion of the articular surface of a joint according to another embodiment. The implant comprises: a main portion configured to be inserted into the joint, wherein the main portion comprises:

[0011] a hydrogel portion that forms a bone contact surface and an articular surface opposite the bone contact surface;

[0012] wherein the main portion has a front end and a rear end, wherein the front end is configured to be inserted into the joint; and

[0013] The bone plate portion, which is configured to fix the implant to the bone forming the joint;

[0014] Wherein the bone plate portion comprises:

[0015] A first portion having a perforated structure, which is embedded in the hydrogel portion; and

[0016] A second portion, which is not embedded in the hydrogel portion and extends from the rear end in a direction opposite to the joint surface at an angle of ≤ 160° but ≥ 80° with respect to the bone contact surface;

[0017] Wherein the second portion has at least one screw hole for receiving a bone screw.

[0018] There is also disclosed an implant for replacing a part of the joint surface of a joint according to another embodiment. The implant comprises: a main portion configured to be inserted into the joint, wherein the main portion comprises:

[0019] A hydrogel portion forming a bone contact surface and a joint surface opposite to the bone contact surface;

[0020] Wherein the bone contact surface comprises a protruding portion;

[0021] Wherein the main portion has a front end and a rear end, wherein the front end is configured to be inserted into the joint; and

[0022] A bone plate portion configured to fix the implant to the bone forming the joint; wherein the bone plate portion comprises:

[0023] A first portion having a perforated structure, which is embedded in the protruding portion of the hydrogel portion; and

[0024] A second portion, which is not embedded in the protruding portion of the hydrogel portion and extends from the rear end in a direction opposite to the joint surface at an angle of ≤ 160° but ≥ 80° with respect to the bone contact surface;

[0025] Wherein the second portion has at least one screw hole for receiving a bone screw.

[0026] There is disclosed an implant for replacing a part of the joint surface of a joint according to yet another embodiment. The implant comprises: a main portion configured to be inserted into the joint and comprising a front end, a rear end, a joint surface, and a bone contact surface extending between the front end and the rear end, wherein the front end is configured to be inserted into the joint, and wherein the main portion further comprises:

[0027] A porous material portion; and

[0028] A hydrogel portion that forms the articular surface and the bone contact surface opposite the articular surface;

[0029] Wherein the porous material portion is bonded to the hydrogel portion, extends partially from the rear end toward the front end, and forms a part of the bone contact surface;

[0030] Wherein the porous material portion includes a tapered hole at the rear end; and

[0031] A bone plate configured to fix the implant to the bones forming the joint;

[0032] Wherein the bone plate is formed of solid metal;

[0033] Wherein the bone plate includes a tapered rod configured to be inserted into the tapered hole in the porous material portion, whereby the tapered rod and the tapered hole cooperate to push the bone contact surface of the implant toward the bone when the implant is inserted into the joint; and

[0034] Wherein the bone plate has at least one screw hole for receiving bone screws.

[0035] The novel implant disclosed herein provides a hydrogel implant with a hybrid structure that allows for the repair of articular cartilage surfaces in various joint spaces that are difficult to repair and provides a durable repair surface by taking advantage of the use of hydrogel materials for the articular surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various embodiments of the inventive hydrogel implant of the present disclosure will be described in more detail in conjunction with the following drawings. The structures in the drawings are schematically shown and are not intended to show actual dimensions.

[0037] Figure 1 is a perspective view of a hydrogel implant according to a first embodiment of the present disclosure.

[0038] Figure 2 is Figure 1 an exploded view of the hydrogel implant.

[0039] Figure 3A is Figure 1 a side view of the hydrogel implant.

[0040] Figure 3B is a side view of the Figure 1 hydrogel implant in the implanted position in the joint.

[0041] Figure 4 is a cross-sectional view of the Figure 1 hydrogel implant taken along the section line H-H shown in FIG. 3.

[0042] Figure 5 The top view of a hydrogel implant that only shows the porous metal foam part, i.e., an implant without a hydrogel part and a solid metal part. Figure 1 The cross-sectional view of the structure shown in

[0043] Figure 6 taken along the section line T-T. Figure 5

[0044] Figure 7 The side view of a hydrogel implant that only shows the porous metal foam and the solid metal part, i.e., an implant without a hydrogel part. Figure 1

[0045] Figure 8 taken along the section line E-E. Figure 7 The cross-sectional view of the structure shown in

[0046] Figure 9 Is Figure 7 The top view of the structure shown in

[0047] Figure 10 Is Figure 1 The top view of a hydrogel implant.

[0048] Figure 11 Is Figure 10 The cross-sectional view of a hydrogel implant taken along the section line M-M shown in

[0049] Figure 12 Is Figure 11 The detailed view of the region N identified in the cross-sectional view.

[0050] Figure 13 The perspective view of a hydrogel implant according to the second embodiment.

[0051] Figure 14 Is Figure 13 The exploded view of a hydrogel implant.

[0052] Figure 15 Is Figure 13 The top view of the bone plate part of a hydrogel implant.

[0053] Figure 16 Is Figure 15 The side view of the bone plate part shown in

[0054] Figure 17 Is Figure 15 The cross-sectional view of the bone plate part taken along the section line F-F shown in

[0055] Figure 18 Is Figure 17 ​​Detailed view of region G identified in the cross-sectional view of

[0056] Figure 19 is Figure 17 Detailed view of region N identified in the cross-sectional view of

[0057] Figure 20 Perspective view of a hydrogel implant according to the third embodiment.

[0058] Figure 21 is Figure 20 Exploded view of the hydrogel implant.

[0059] Figure 22 is Figure 20 Top view of the bone plate portion of the hydrogel implant.

[0060] Figure 23 is taken through Figure 22 Cross-sectional view of the bone plate portion taken along the section line C-C shown in

[0061] Figure 24 is Figure 23 Detailed view of region E identified in the cross-sectional view of

[0062] Figure 25 Illustration of an example of a mold that can be used to form the hydrogel implant of the present disclosure by injection molding.

[0063] Figure 26 is Figure 25 Cross-sectional view of the injection molding device shown in

[0064] Figure 27 Perspective view of a hydrogel implant according to the fourth embodiment.

[0065] Figures 28 to 29 shows a Figure 27 hydrogel implant implanted in some arch joints.

[0066] Figure 30 is Figure 27 Perspective view of the main part of the hydrogel implant.

[0067] Figure 31 shows Figure 30 Illustration of a view of the bone contact surface of the main part shown in

[0068] Figure 32 is Figure 31 Top view of the main part shown in

[0069] Figure 33 is Figure 31 Side view of the main part shown in

[0070] Figure 34 is taken along section line A-A shown in Figure 32 and is a cross-sectional view of the main part shown in Figure 31

[0071] Figure 35 is a perspective view of a hydrogel implant that is fixed to bone in its fully implanted configuration Figure 27

[0072] Figure 36 is Figure 35 a cross-sectional view of the hydrogel implant shown in

[0073] Figure 37 is Figure 35 a cross-sectional view of the hydrogel implant shown in

[0074] Figure 38 is a perspective view of a hydrogel implant according to another embodiment of the present disclosure

[0075] Figure 39 is Figure 38 an exploded view of the hydrogel implant

[0076] Figure 40 is Figure 38 a side view of the hydrogel implant

[0077] Figure 41 is taken along section line V-V shown in Figure 40 and is a cross-sectional view of the hydrogel implant shown in Figure 38

[0078] Figure 42 is Figure 38 a top view of the hydrogel implant

[0079] Figure 43 is taken along section line AF-AF shown in Figure 42 and is a cross-sectional view of the hydrogel implant

[0080] Figure 44 is Figure 43 a detailed view of region AG identified in the cross-sectional view DETAILED DESCRIPTION

[0081] ​​​This description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered to be a part of the entire written description. The drawings are not necessarily to scale, and in order to be clear and concise, some features may be enlarged in scale or shown in a schematic form. In the specification, relative terms such as "horizontal", "vertical", "upward", "downward", "top", and "bottom", and their derivatives (e.g., "horizontally", "downwardly", "upwardly", etc.) are to be construed as referring to the orientation shown in the drawings that is being described or discussed at that time. These relative terms are for ease of description and generally do not require a particular orientation. Terms including "inwardly" and "outwardly", "longitudinally" and "transversely", etc. will be construed relative to each other or relative to an elongation axis, or a rotation axis, or a center of rotation, as the case may be. Terms regarding attachment, coupling, etc., such as "connected" and "interconnected", refer to a relationship in which structures are directly or indirectly fixed or attached to each other through an intermediate structure, and a movable or rigid attachment or relationship, unless otherwise expressly stated. When only a single machine is shown, the term "machine" should also be considered to include any collection of machines that individually or jointly execute a set (or sets) of instructions to perform any one or more of the methods discussed herein. The term "operatively connected" is such an attachment, coupling, or connection that allows the related structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses (if used) are intended to cover structures described, suggested, or obvious from the written description or the drawings for performing the recited function, including not only structural equivalents but also equivalent structures.

[0082] According to Figures 1 to 12 the embodiment illustrated in Figure 1 an implant 100 for replacing a portion of an articular surface of a joint is disclosed. As Figure 2 shown in the exploded view of

[0083] Referring to Figure 2 and Figure 3A, the hydrogel portion 112 forms an articular surface 114 that is oppositely positioned to the first bone engaging surface 130. In other words, the articular surface 114 and the first bone engaging surface 130 face away from each other. The bone plate portion 120 includes a solid metal portion 122 that forms all of the outer surfaces of the bone plate portion 120 except for the second bone engaging surface 140. The second bone engaging surface 140 of the bone plate portion 120 is formed of the same porous material as the porous material portion 115 and is preferably integrally formed with the porous material portion 115 as a monolithic structure to facilitate manufacturing and produce a more compact structure.

[0084] The bone plate portion 120 includes at least one screw hole 150 for receiving a bone screw for fixing the implant 100 to the bone. More than one screw hole may be provided in the bone plate portion 120 for joint repair sites where more than one bone screw may be required to fix the implant.

[0085] The main portion 110 of the implant 100 has a front end 111 and a rear end 113, where the front end is configured to be inserted into the joint. Here, the terms "front" and "rear" generally refer to the orientation of the implant in its implanted position in the joint space and also refer to the orientation when the implant is inserted into the joint space.

[0086] The bone plate portion 120 is integrally formed with the porous material portion 115 and extends from the rear end to form the second bone engaging surface 140. Since the extension 117 is formed of the same porous material as the porous material portion 115, the second bone engaging surface 140 also promotes cancellous bone growth into the second bone engaging surface 140 and enhances the stability of the implant at the repair site.

[0087] As shown by the dashed line in the side view of the implant 100 in Figure 3A , the porous material portion 115 has an extension 117 that extends from the first bone engaging surface 130 at an angle θ in a direction opposite to the articular surface 114 with respect to the first bone engaging surface 130. The angle θ between the first bone engaging surface 130 and the second bone engaging surface 140 is selected to enable the implant to be firmly attached to the bone. In some embodiments, the angle may be substantially 90°. This means that the angle may be 90° ± 2°. In some embodiments, the angle is an obtuse angle. In some embodiments, the obtuse angle ≥ 110° and ≤ 160°. In some embodiments, the obtuse angle ≥ 130° and ≤ 140°.

[0088] The extension 117 is provided to form the second bone engaging surface 140. The porous material portion 115 and the extension 117 together provide a framework infrastructure to which the hydrogel portion 112 is applied and bonded. This framework structure is in Figure 5 andFigure 6 is shown. The solid metal portion 122 fills the space 118 between the extension 117 and the porous material portion 115. In some embodiments, the solid metal portion 122 may be integrally formed with the porous material portion 115 and the extension 117. Figures 7 to 9 The porous material structures 115, 117 and the solid metal portion 122 are shown together.

[0089] In Figure 5 and Figure 6 , since only the porous material structures 115 and 117 are shown without the solid metal portion 122, the holes 150A in the extension 117 are larger than the bone screw holes 150, which are the final sized screw holes formed by the solid metal portion 122 covering the extension 117.

[0090] In a preferred embodiment, the porous material structures 115, 117 and the solid metal portion 122 are formed as an integral structure. For example, the porous material structure and the solid metal portion 122 can be 3D printed and sintered to form an integral structure.

[0091] In some embodiments, the bone plate portion 120 and the porous material portion 115 are formed of surgical grade metal. In a preferred embodiment, the surgical grade metal used is titanium. In a more preferred embodiment, the solid metal portion 122 is formed of titanium metal, and the porous material portion 115 and the extension 117 are made of porous titanium metal foam.

[0092] The hydrogel portion 112 is bonded to the porous material portion by infiltrating some hydrogel material into the holes of the porous material portion. In a preferred embodiment where the porous material is porous titanium metal foam, the hydrogel material infiltrates into the holes of the porous titanium metal foam.

[0093] The porous material may include oxide materials. The porous material may include at least one of the surgical grade materials approved for human implantation, such as aluminum, alumina, zirconia, titanium, titanium dioxide, stainless steel, PEEK, and talc. The porous material may have a porosity between 45 ppi and 80 ppi. The holes of the porous material may have a size between 100 μm and 500 μm. The porous material may be ceramic, metal, or plastic. In some embodiments, the porous material includes porous ceramic materials (such as oxide ceramics), metals (such as titanium (such as titanium mesh, printed titanium), stainless steel (such as stainless steel wool), plastics (such as polyaryletherketone (PAEK) (such as polyetheretherketone (PEEK)), other biocompatible materials, combinations thereof, etc.). In some preferred embodiments, the porous material is a porous metal foam material having an open pore three-dimensional scaffold structure for bone and tissue growth.

[0094] In a more preferred embodiment, the porous metal foam material is a porous titanium foam. An example of such a porous titanium foam material is the Cancellous Titanium TM technology of Wright Medical Technology, Inc. Cancellous Titanium TM The titanium matrix of the technology has a fully interconnected porosity of up to 70%, thus providing an ideal environment for optimal bone growth and fusion. Cancellous Titanium TM The titanium matrix of the technology has: a compressive strength between that of cortical bone and cancellous bone, thus minimizing deformation under dynamic loading conditions; a compressive modulus close to that of cancellous bone, thus allowing dynamic loads to naturally transfer away from the implant to the surrounding bone; and a high surface friction coefficient, which provides initial stability at the interface between the implant and the bone, thus minimizing micromotion and creating a stable environment for rapid ingrowth and fixation. Examples of alternative materials for the porous metal foam are titanium dioxide foam and porous tantalum foam.

[0095] Reference Figure 3B , when the implant 100 is implanted into a patient's body to repair or replace a portion of the articular surface in a joint (e.g., articular cartilage), the damaged articular surface and the adjacent bone region will be ready to receive the implant 100. The prepared site will have resected bone surfaces B1 and B2 corresponding to the first bone engagement surface 130 and the second bone engagement surface 140 of the implant 100. All or most of the resected bone surfaces B1 and B2 will typically consist of cancellous bone, and since the first bone engagement surface 130 and the second bone engagement surface 140 are formed of a porous metal foam material having a reticulated structure with many pores mimicking the cancellous bone structure, cancellous bone grows into the porous metal foam structure and further enhances the fixation of the implant 100 at the repair site.

[0096] The hydrogel portion 112 can be formed by applying a hydrogel material in liquid form onto the porous material structure 115 in a mold and then crosslinking the hydrogel material by performing an appropriate process suitable for the particular type of hydrogel material selected for a given application of the implant.

[0097] In some embodiments of the implant 100, the bond between the hydrogel portion and the porous material portion is enhanced by allowing some of the hydrogel material to infiltrate into the pores of a portion of the porous material along the surface in contact with the hydrogel material. Thus, in the region of the porous material structure 115 along the hydrogel portion 112, the hydrogel material and the porous material coexist, while in the remaining portion of the porous material structure 115 towards the bone-engaging surface 130, only the porous material is present without any hydrogel material. This allows the bone-engaging surface 130 to present pores capable of allowing cancellous bone to grow inwards.

[0098] The hydrogel material referred to herein means a three-dimensional solid produced by cross-linked hydrophilic polymer chains formed from polyvinyl alcohol (PVA). In addition to PVA, the hydrogel material may include one or more other materials, such as other hydrogels, other polymeric materials, additives, and the like. In some embodiments, the PVA content of the hydrogel in the implant disclosed herein may be about 40 wt%. Depending on the specific application, the PVA content of the hydrogel may range from about 10 wt% to about 80 wt%.

[0099] The hydrogel may include water, saline, other liquids, combinations thereof, and the like. In some embodiments, saline may be preferred over water because in certain cases, saline can help maintain an osmotic balance with the surrounding anatomical tissues after implantation. The exact composition of the hydrogel component in the implant can be selected to obtain optimal performance in a particular application to achieve the desired or required strength, load-bearing capacity, compressibility, flexibility, lifespan, durability, resilience, coefficient of friction, and / or other properties and characteristics.

[0100] In some embodiments, such a hydrogel portion of the implant may be formulated for drug delivery and / or seeding of growth factors and / or cells. In such embodiments, the hydrogel component may include one or more of the following: chondrocytes, growth factors, bone morphogenetic proteins, collagen, hyaluronic acid, nucleic acids, and stem cells. Such factors and / or any other materials included in the implant can help promote and / or facilitate long-term fixation of the implant at the joint site.

[0101] Figure 10 is a top view of the hydrogel implant 100. Figure 11 is through Figure 10 The cross-sectional view of the hydrogel implant 100 taken along the section line M-M shown in. Figure 12 is Figure 11 The detailed view of the region N identified in the cross-sectional view of.

[0102] Refer to Figures 38 to 41 , disclose an implant 100A for replacing a portion of the articular surface of a joint according to another embodiment. As Figure 38As shown, the implant includes a main portion 110A configured to be inserted into a joint; and a bone plate portion 120A that extends from the main portion 110A at an angle and is configured to secure the implant 100A to the bones forming the joint. As Figure 39 shown in the exploded view of, the implant 100A includes four different components joined together in the following order: a first porous material portion 117A, a solid metal portion 116A, a second porous material portion 115A, and a hydrogel portion 112A.

[0103] Referring to Figure 39 and Figure 40 which are side views of the implant 100A, the first porous material portion 117A has a first bone-engaging surface 130A and a second bone-engaging surface 140A. The top portion 121A of the first porous material portion 117A forms the second bone-engaging surface 140A, and the remaining portion of the first porous material portion 117A forms the first bone-engaging surface 130A. On opposite sides of the two bone-engaging surfaces 130A, 140A, the solid metal portion 116A is joined to the first porous material portion 117A.

[0104] The solid metal portion 116A includes a top portion 122A that, together with the top portion 121A of the first porous material portion 117A, forms the bone plate portion 120A of the implant 100A. Similar to the implant 100 described above, the bone plate portion 120A of the implant 100A also includes at least one screw hole for receiving a bone screw for securing the implant 100A to the bone. In the illustrated example, two screw holes 150A and 151A are provided in the bone plate portion 120A for a joint repair site where more than one bone screw may be needed to secure the implant. The top portion 121A of the first porous material portion 117A includes holes 150A' and 151A' corresponding to the two screw holes 150A and 151A.

[0105] The top portion 122A of the solid metal portion 116A forms the outer surface of the bone plate portion 120A, while the second bone-engaging surface 140A is formed by the first porous material portion 117A.

[0106] The second porous material portion 115A is located between and joined to the solid metal portion 116A and the hydrogel portion 112A. The hydrogel portion 112A forms an articular surface 114A that is positioned opposite the first bone-engaging surface 130A. In other words, the articular surface 114A and the first bone-engaging surface 130A face away from each other.

[0107] The main portion 110A of the implant 100A has a front end 111A and a rear end 113A, where the front end 111A is configured to be inserted into a joint. Here, the terms "front" and "rear" generally refer to the orientation of the implant in its implanted position in the joint space and also refer to the orientation when the implant is inserted into the joint space.

[0108] Both the first porous material portion 117A and the second porous material portion 115A are preferably made of the same porous material. The first porous material portion 117A that forms the first bone-engaging surface 130A and the second bone-engaging surface 140A respectively promotes cancellous bone growth into the bone-engaging surfaces 130A, 140A and enhances the stability of the implant at the repair site.

[0109] As Figure 40 shown, the first bone-engaging surface 130A is substantially parallel to the articular surface 114A of the hydrogel portion 112A. The second bone-engaging surface 140A of the bone planar portion 120A and the first bone-engaging surface 130A form an angle θ with respect to the first bone-engaging surface 130. The angle θ between the first bone-engaging surface 130A and the second bone-engaging surface 140A is selected to enable the implant to be firmly attached to the bone. In some embodiments, the angle can be substantially 90°. This means the angle can be 90° ± 2°. In some embodiments, the angle is an obtuse angle. In some embodiments, the obtuse angle ≥ 110° and ≤ 160°. In some embodiments, the obtuse angle ≥ 130° and ≤ 140°.

[0110] The first porous material portion 117A, the solid metal portion 116A, and the second porous material portion 115A together provide a framework infrastructure to which the hydrogel portion 112A is applied and bonded. In some embodiments, the solid metal portion 116A can be integrally formed with the first porous material portion 117A and the second porous material portion 115A as a monolithic structure. For example, the porous material structure and the solid metal portion 116A can be 3D printed and sintered to form a monolithic structure.

[0111] As in implant embodiment 100, the solid metal portion 116A and the porous material portions 117A, 115A can be formed of a surgical-grade metal such as titanium and / or a titanium alloy.

[0112] The hydrogel portion 112A is bonded to the second porous material portion 115A by allowing some hydrogel material to penetrate into the pores of the porous material portion. In a preferred embodiment where the porous material is porous titanium metal foam, the hydrogel material penetrates into the pores of the porous titanium metal foam. The porous material can include the materials described above in connection with implant 100.

[0113] When implanted in a patient, the arrangement of the implant 100A will be similar toFigure 3B An example of the implant 100 shown in

[0114] The hydrogel portion 112A can be formed by applying a hydrogel material in liquid form onto a porous material structure 115A in a mold and then crosslinking the hydrogel material by performing an appropriate process suitable for the specific type of hydrogel material selected for a given application of the implant.

[0115] In some embodiments of the implant, the bond between the hydrogel portion and the porous material portion is enhanced by allowing some of the hydrogel material to infiltrate into the pores in a portion of the porous material along the surface in contact with the hydrogel material. Thus, in the region of the porous material structure 115A along the hydrogel portion 112A, the hydrogel material and the porous material coexist, while in the remaining portion of the porous material structure 115A towards the bone-engaging surface 130A, only the porous material is present without any hydrogel material. This allows the bone-engaging surface 130A to present pores capable of allowing cancellous bone to grow inwards.

[0116] Figure 42 is a top view of the hydrogel implant 100A. Figure 43 is through Figure 42 a cross-sectional view of the hydrogel implant 100A taken along the section line AF-AF shown in Figure 44 is Figure 43 a detailed view of the region AG identified in the cross-sectional view of

[0117] Refer to Figures 13 to 19 , which discloses an implant 200 for replacing a part of the articular surface of a joint according to another embodiment. The implant 200 includes a main portion 210 configured to be inserted into the joint. The main portion 210 may include a hydrogel portion 212 forming a bone contact surface 230 and an articular surface 214 opposite to the bone contact surface 230. The main portion 210 has a front end 211 and a rear end 213, wherein the front end is configured to be inserted into the joint. The bone plate portion 220 is configured to fix the implant 200 to the bones forming the joint. The bone plate portion 220 includes a first portion 223 having a perforated structure, which is embedded in the hydrogel portion 212; and a second portion 225, which is not embedded in the hydrogel portion and extends from the rear end 213 in a direction opposite to the articular surface 214 at an angle of ≤ 160° but ≥ 80° with respect to the bone contact surface 230. The second portion 225 has at least one screw hole 250 for receiving a bone screw (not shown). The second portion 225 may have a generally circular configuration around the screw hole 250, as shown in Figure 15 but the shape of the second portion 225 can be designed to have any suitable shape to adapt to the bone structure (e.g., profile) around the specific joint space into which the implant 200 is to be implanted.

[0118] In some embodiments of the implant 200, the second portion 225 extends from the rear end 213 at an angle of ≤ 110° and ≥ 80°. In some embodiments of the implant 200, the second portion 225 extends from the rear end 213 at an angle that is substantially 90° (i.e., 90 ± 2°). In some embodiments of the implant 200, the first portion 223 of the bone plate portion 220 is embedded in the hydrogel portion 212 and is positioned closer to the bone contact surface 230 than the articular surface 214. In some embodiments of the implant 200, the bone contact surface 230 is a flat surface. When the bone contact surface 230 is a flat surface, the first portion 223 of the bone plate portion 220 has a substantially flat configuration as shown in Figure 13 and Figure 14 to correspond to the flat profile of the bone contact surface 230.

[0119] The implant 200 can be formed by molding a hydrogel material around the first portion 223 of the bone plate portion 220 using injection molding or cavity molding processes known to those skilled in the art. As shown in Figure 14 and Figure 19 , the first portion 223 of the bone plate portion 220, i.e., the portion embedded in the hydrogel portion 212, can be perforated with holes 227 to better enable the hydrogel material to closely surround and coat the first portion 223 during the molding process, such that the resulting implant 200 has optimal structural integrity.

[0120] The bone plate portion 220 is made of a surgical grade metal such as stainless steel, cobalt-based superalloy, titanium, titanium alloy, etc. In some embodiments, the surgical grade metal is titanium.

[0121] Reference Figures 20 to 24 discloses an implant 300 according to another embodiment. The implant 300 is similar to the implant 200 just described, with one difference being that a protrusion portion 316 is provided on the bone contact surface 330.

[0122] An implant 300 for replacing a portion of the articular surface of a joint includes a main portion 310 configured to be inserted into the joint. The main portion 310 includes a hydrogel portion 312 that forms a bone contact surface 330 and an articular surface 314 opposite the bone contact surface 330. The bone contact surface 330 includes a protrusion portion 316 that provides additional structural stability at the interface between the bone and the bone contact surface 330 when the implant 300 is implanted in place in the joint space. Preferably, the bone surface that receives the implant 300 will be prepared to have a profile complementary to the profile of the bone contact surface 330 that includes the protrusion portion 316.

[0123] Similar to implant 200, the main portion 310 of implant 300 includes a front end 311 and a rear end 313, wherein the front end 311 is configured to be inserted into a joint. Implant 300 also includes a bone plate portion 320, which is configured to fix implant 300 to the bones forming the joint. The bone plate portion 320 includes a first portion 323 having a perforated structure embedded in a protrusion portion 316 of the hydrogel portion 312 and a second portion 325 not embedded in the protrusion portion of the hydrogel portion. The second portion 325 extends from the rear end 313 at an angle of ≤ 160° but ≥ 80° with respect to the base flat portion of the bone contact surface 330 (i.e., the portion of the bone contact surface 330 that does not include the protrusion portion 316) in a direction opposite to the joint surface 314. The second portion has at least one screw hole 350 for receiving a bone screw (not shown). Similar to implant 200, the second portion 325 may have a generally circular configuration around the screw hole 350, as Figure 21 shown, however, the shape of the second portion 325 can be designed to have any suitable shape to fit the bone structure (e.g., profile) around the specific joint space into which implant 300 will be implanted.

[0124] In some embodiments of implant 300, the second portion 325 extends from the rear end 313 at an angle of ≤ 110° and ≥ 80°. In some embodiments of implant 300, the second portion 325 extends from the rear end 313 at an angle of substantially 90° (i.e., 90 ± 2°). In some embodiments, the first portion 323 of the bone plate portion is embedded in the hydrogel portion and is positioned closer to the bone contact surface 330 than the joint surface 314. Preferably, the first portion 323 of the bone plate portion 320 has a profile that substantially matches the profile of the protrusion portion 316 of the hydrogel portion 312.

[0125] In some embodiments, the protrusion portion 316 of the bone contact surface 330 has a semi-cylindrical profile and the first portion 323 of the bone plate portion has a complementary curved profile. In some embodiments of implant 300, the bone plate portion 320 is made of a surgical grade metal such as stainless steel, cobalt-based superalloy, titanium, titanium alloy, etc. In some embodiments, the surgical grade metal is titanium.

[0126] Reference Figure 25 and Figure 26 disclose examples of the molding process for forming implants 200 and 300. A mold 500 having a plurality of mold cavities 510 is provided. Each mold cavity 510 is configured with the profile shape of implant 200 or implant 300. First, the bone plate portion 220 or 320 is placed in each mold cavity 510. Then, a nozzle 550 for dispensing the hydrogel material is positioned into the mold cavity 510, as Figure 26As shown. Next, the hydrogel material represented by arrow 600 is dispensed into each cavity 510. Next, with each cavity 510 holding the bone plate portion 220 and filled with the hydrogel material, appropriate post-treatment is performed to crosslink the hydrogel material to form the finished implant product 200. This process is also applicable to implant 300. The details of this post-treatment will be determined by the specific hydrogel material used, but are well-known to those skilled in the art for a particular formulation of the hydrogel.

[0127] Reference Figures 27 to 37 , discloses another embodiment of an implant 400 for replacing a portion of the articular surface of a joint. Implant 400 includes a main portion 410 configured to be inserted into a joint; and a bone plate portion 420 configured to secure implant 400 to the bone forming the joint.

[0128] Reference Figure 30 , the main portion 410 includes a front end 411, a rear end 413, an articular surface 414, and a bone contact surface 430 extending between the front end and the rear end. The front end 411 is configured to be inserted into the joint. The main portion 410 also includes a porous material portion 415 and a hydrogel portion 412, and the hydrogel portion forms the articular surface 414 and the bone contact surface 430 opposite the articular surface 414. The porous material portion 415 is bonded to the hydrogel portion 415 and the porous material portion 415 partially extends from the rear end 413 towards the front end 411 and forms a part of the bone contact surface 430.

[0129] Reference Figure 30 and Figure 34 In the cross-sectional view of, the porous material portion 415 includes a tapered hole 460 at the tail end 413.

[0130] Reference Figure 36 and Figure 37 In the cross-sectional view of, in some embodiments, the bone plate 420 is formed of solid metal and includes a tapered rod 427 configured to be inserted into the tapered hole 460 in the porous material portion 415. When implant 400 is inserted into the joint, the tapered rod 427 and the tapered hole 460 cooperate to push the bone contact surface 430 of implant 400 against the bone. Reference Figure 27 , Figures 35 to 36 , the bone plate 420 includes at least one screw hole 450 for receiving a bone screw S.

[0131] The porous material for the porous material portion 415 can be the same material as the porous material portion 115 of the above implant 100.

[0132] In some embodiments, the hydrogel portion 412 is bonded to the porous material portion 415 by infiltrating some of the pores of a portion of the porous material portion with some hydrogel material. The main portion 410, which includes the hydrogel portion 412 and the porous material portion 415, can be formed by suitable processes, such as the injection molding or open cavity molding processes described above in connection with implant embodiment 100.

[0133] Figures 35 to 37 The bone of the joint in which the implant 400 is fixed is shown. For illustrative purposes, a portion of the bone directly surrounding the implant 400 is conceptually shown as a box-shaped volume of bone. Figure 36 and Figure 37 Shows how the tapered rod 427 of the bone plate 420 and the tapered holes 460 of the porous material portion 415 engage and cooperate with each other to push the bone contact surface 430 of the implant 400 against the bone when the implant 400 is inserted into the joint. Figure 36 Shows the implant 400 positioned in the appropriate location in the bone. The bone contact surface 430 contacts the prepared bone surface B3. The tapered rod 427 of the bone plate 420 is partially inserted into the mating tapered holes 460 in the porous material portion 415, and the bone screw S passes through the screw holes 450 in the bone plate 420 and begins to engage the pre-drilled holes in the bone. Figure 37 Shows the implant 400 in which the bone screw S has been fully screwed into the bone and the bone plate 420 has been fixed to the bone. With the bone plate 420 in its fully seated position, the tapered rod 427 is fully inserted into the tapered hole 460. When the tapered rod 427 reaches its fully seated position and holds the main portion 410 of the implant 400 firmly in place, the tapered surface of the tapered rod 427 bears against the sidewall of the tapered hole 460.

[0134] In Figure 28 and Figure 29 two examples of the implant 400 are shown implanted in the joint space between the metatarsal bone and the cuneiform bone. In Figure 29 a third implant 400 is shown implanted in the subtalar joint space between the talus bone and the calcaneus bone.

[0135] Although the devices, kits, systems, and methods have been described in accordance with exemplary embodiments, they are not limited thereto. Instead, the appended claims should be construed broadly to include other variations and embodiments of the devices, kits, systems, and methods that those skilled in the art can make without departing from the scope and range of equivalents of the devices, kits, systems, and methods.

Claims

1. An implant for replacing a part of the articular surface of a joint, the implant comprising: A main part configured to be inserted into the joint, wherein the main part comprises: A porous material part having a first bone-engaging surface; and A hydrogel part bonded to the porous material part and forming an articular surface opposite to the first bone-engaging surface; and A bone plate part configured to fix the implant to the bones forming the joint; Wherein the main part has a front end and a rear end, wherein the front end is configured to be inserted into the joint; Wherein the bone plate part extends from the rear end, the porous material part has an extension that extends from the first bone-engaging surface and forms a second bone-engaging surface, the second bone-engaging surface is also formed by the porous material and extends from the first bone-engaging surface in a direction opposite to the articular surface at an angle with respect to the first bone-engaging surface; Wherein the bone plate part includes a solid metal part that forms all the outer surfaces of the bone plate part except the second bone-engaging surface, and the solid metal part fills the space between the extension and the porous material part; Wherein the hydrogel part is bonded to the porous material part by infiltrating some hydrogel material into the pores of the porous material part having the first bone-engaging surface and the second bone-engaging surface, and Wherein the bone plate part has at least one screw hole for receiving a bone screw.

2. The implant according to claim 1, wherein the porous material is a porous metal foam.

3. The implant according to claim 1, wherein the porous material is a porous titanium foam.

4. The implant according to claim 1, wherein the angle between the first and second bone-engaging surfaces is 90°.

5. The implant according to claim 1, wherein the angle between the first and second bone-engaging surfaces is an obtuse angle.

6. The implant according to claim 5, wherein the obtuse angle ≥ 110° and ≤ 160°.

7. The implant according to claim 5, wherein the obtuse angle ≥ 130° and ≤ 140°.

8. The implant according to claim 1, wherein the porous material is formed of a porous titanium metal foam.

9. The implant according to claim 1, wherein the bone plate part and the porous material part are formed of a porous titanium metal foam.

10. An implant for replacing a part of the articular surface of a joint, the implant comprising: A main part configured to be inserted into the joint, wherein the main part comprises: A hydrogel part forming a bone contact surface and an articular surface opposite to the bone contact surface; Wherein the bone contact surface includes a protruding part; Wherein the main part has a front end and a rear end, wherein the front end is configured to be inserted into the joint; and A bone plate part configured to fix the implant to the bones forming the joint; wherein the bone plate part comprises: A first part having a perforated structure embedded in the protruding part of the hydrogel part; A second portion that is not embedded in the protruding portion of the hydrogel portion and extends from the rear end in a direction opposite to the joint surface at an angle of ≤ 160° but ≥ 80° relative to the bone contact surface; wherein the first portion of the bone plate portion has a contour that substantially matches the contour of the protruding portion of the bone contact surface; and wherein the second portion has at least one screw hole for receiving a bone screw.

11. The implant according to claim 10, wherein the second portion extends from the rear end at an angle of ≤ 110° and ≥ 80°.

12. The implant according to claim 10, wherein the second portion extends from the rear end at an angle of 90°.

13. The implant according to claim 10, wherein the first portion of the bone plate portion is embedded in the hydrogel portion and is positioned closer to the bone contact surface than the joint surface.

14. The implant according to claim 10, wherein the protruding portion of the bone contact surface has a semi-cylindrical contour.

15. The implant according to claim 10, wherein the bone plate portion is made of surgical-grade metal.

16. The implant according to claim 10, wherein the bone plate portion is made of titanium.

17. An implant for replacing a portion of the joint surface of a joint, the implant comprising: A main portion configured to be inserted into the joint and including a front end, a rear end, a joint surface, and a bone contact surface extending between the front end and the rear end, wherein the front end is configured to be inserted into the joint, and wherein the main portion further includes: A porous material portion; and A hydrogel portion that forms the joint surface and the bone contact surface opposite to the joint surface; wherein the porous material portion is bonded to the hydrogel portion, extends partially from the rear end toward the front end, and forms a portion of the bone contact surface; wherein the porous material portion includes a tapered hole at the rear end; and A bone plate configured to fix the implant to the bone forming the joint; wherein the bone plate is formed of solid metal; wherein the bone plate includes a tapered rod configured to be inserted into the tapered hole in the porous material portion, whereby the tapered rod and the tapered hole cooperate to push the bone contact surface of the implant against the bone when the implant is inserted into the joint; and wherein the bone plate has at least one screw hole for receiving a bone screw.

18. The implant according to claim 17, wherein the porous material is a porous metal foam.

19. The implant according to claim 17, wherein the porous material is a porous titanium foam.

20. The implant according to claim 17, wherein the metal is surgical-grade metal.

21. The implant according to claim 20, wherein the metal is titanium.

22. The implant according to claim 18, wherein the hydrogel portion is bonded to the porous metal foam by allowing some hydrogel material to penetrate into the holes in a portion of the porous metal foam.

23. The implant according to claim 18, wherein the bone plate portion and the porous metal foam are formed of titanium.

24. The implant according to claim 18, wherein the porous metal foam is a porous titanium metal foam.

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