Tibial base plate of the tibial component of a knee prosthesis (the tibial component includes the tibial base plate) and method for manufacturing the tibial base plate.

Abstract

This disclosure relates to a tibial substrate (1) for the tibial component of a knee prosthesis, comprising: a bulk solid portion (2) including a proximal-facing surface (3) adapted to receive a support element (100) for the femoral component of the articulated knee prosthesis; and a plurality of porous portions (5) integrated with the bulk solid portion (2) having a porous portion contact surface (6) opposite to the proximal-facing surface (3) adapted to contact the proximal tibia. Advantageously, the plurality of porous portions (5) are seamlessly incorporated into and embedded in the bulk solid portion (2).

Description

Technical Field

[0001] This invention relates to a tibial substrate for the tibial component of a knee prosthesis. More particularly, this type of tibial substrate includes at least a porous portion to allow bone ingrowth.

[0002] The tibial substrate can be suitably used in the cementless tibial component of a knee prosthesis.

[0003] The present invention also relates to a tibial component including the tibial substrate and a method for manufacturing the tibial substrate.

[0004] The present invention also relates to a kit including a tibial plate and an implant removal tool. Background Technology

[0005] As is known in the art, a total knee prosthesis typically comprises two interlocking prosthetic components that replicate the kinematics of a natural joint: a femoral component attached to the distal femur and a tibial component attached to the proximal tibia.

[0006] The tibial component further includes a metal plate attached to the previously transversely cut tibial platform. A polymer liner, serving as a low-wear bearing for the articulation of the femoral component, is typically fixed to the top of the metal plate.

[0007] Depending on the type of bone fixation, the prostheses used in this field are referred to as cemented or uncemented.

[0008] In cemented knee prostheses, the components are fixed to the bone using bone cement. In contrast, uncemented knee prostheses are fixed directly to the bone.

[0009] To facilitate osseointegration of the implant, cementless substrates are typically equipped with a porous material that contacts the bone to allow for inward bone growth. A stabilizing element extending from the bone-contacting surface of the substrate into the bone is also usually provided.

[0010] More specifically, the monolithic tibial component includes a substrate made of porous material that is bonded or fused entirely beneath the polymer liner.

[0011] The uncemented tibial component can also be modular. In this case, the tibial component is equipped with a base plate that allows for the removable attachment of polymer liners. In this way, surgeons can select different heights to balance the knee joint and replace the liners in case of damage.

[0012] In this type of composition, the substrate includes a proximal solid portion having a proximal surface designed to accommodate a liner, and a distal porous portion having a distal surface that contacts the tibial plateau.

[0013] The porous portion is glued or fused to the solid portion below.

[0014] Despite its advantages in various aspects and its responsiveness to purpose, the non-cemented tibial component of the prior art has a number of disadvantages, and more particularly, due to the presence of interfaces (bonded or fused materials) between the liner and the substrate (modular tibial component) and between the solid and porous portions of the substrate (in the prior art, the porous portion is added to the solid portion in a second step).

[0015] Because the tibial component is subjected to cyclic loading throughout implantation, the presence of the interface between the solid and porous portions promotes degradation phenomena such as delamination and current effects. This degradation reduces the structural robustness and mechanical strength of the interface, leading to implantation failure.

[0016] More specifically, this phenomenon can lead to incorrect load transfer to the bone, which facilitates bone resorption that determines at least partial detachment of the implant.

[0017] The potential technical problem of the present invention is to provide a substrate with structural and functional features that allows overcoming the shortcomings of the prior art and, more particularly, high structural robustness and mechanical resistance, while ensuring proper fixation to the bone and implantation stability throughout the implantation process.

[0018] Another object of the present invention is to provide a tibial component comprising the above-described innovative tibial substrate, and a method for manufacturing such a tibial substrate. Invention Overview

[0020] The previously identified technical problems were resolved by the tibial base plate of the tibial component of the knee prosthesis, including:

[0021] - A large solid portion, which includes a proximal surface adapted to accommodate a load-bearing element for the femoral component of an articulated knee prosthesis;

[0022] - Multiple porous portions, which are integrated with the bulk solid portion having a porous portion contact surface opposite to the proximal surface suitable for contacting the proximal tibia;

[0023] The plurality of porous portions are seamlessly incorporated into and embedded within the bulk solid portion.

[0024] In other words, the tibial substrate is a single element comprising a bulk portion of solid material and multiple portions of porous material integrated within the bulk portion, seamlessly transitioning between porous and solid.

[0025] The absence of a junction provides the substrate with enhanced structural robustness and adhesive resistance compared to existing tibial substrates, reducing the risk of delamination, peeling, and current effects typical of macro-rough coatings.

[0026] Tibial lamina can be made of titanium or titanium alloy.

[0027] Tibial substrates can be manufactured entirely through additive manufacturing methods, such as electron beam melting, or even in a single step.

[0028] Additive manufacturing allows the entire tibial substrate to be built layer by layer. In this way, it becomes possible to create tibial substrates with complex structures, such as incorporating porous portions into a solid block. There is no need to separately produce the solid and porous portions and then assemble them together as a substrate using existing technology.

[0029] Porous portions with a thickness of 0.8 to 1.2 mm, such as 1.2 mm, can be created to allow for full interconnection of porous structures, which provides an optimal foundation for bone ingrowth.

[0030] This approach optimizes the ratio between the solid and porous phases to ensure good bone ingrowth conditions and reduce micromovement during substrate implantation.

[0031] The tibial substrate includes multiple porous portions incorporated within a bulk solid portion, wherein the porous portions are separated from each other by components of the bulk solid portion. In other words, the porous portions are embedded within the bulk solid portion. The solid portions between the porous portions serve as reinforcements for the overall structure, increasing the strength of the substrate.

[0032] The tibial platen may include at least one stabilizing element adapted to be inserted into the proximal tibia extending from the distal end of the bone contact surface of the tibial platen opposite to the proximal surface, and adapted to be placed in direct contact with bone tissue cutting the tibial plateau.

[0033] More specifically, the stabilizing element can extend from multiple porous sections.

[0034] At least one stabilizing element is made partly or entirely of a porous material, such as the same as the porous portion, to further reduce micromovement and improve load transfer.

[0035] Porous stabilizing elements are easier to cut than solid elements.

[0036] At least one stabilizing element may be located in front of the tibial base plate to reduce micromovement and prevent it from rising from the tibial base plate due to posterior or posterior loads during implantation.

[0037] More specifically, a pointed object may be provided at the front. This pointed object has a generally pyramidal shape with a generally triangular, concave base. At least one side of this triangular base is longer than the other sides. More specifically, the base of the pyramid may be essentially an equilateral triangle, with its base positioned in front of the pointed tip.

[0038] At least one stabilizing element may also include a matrix made of a porous material and a tip made of a solid material; the solid material facilitates insertion into the proximal tibia and restricts bone ingrowth at the tip, making correction easier.

[0039] The tibial plate may include at least two stabilizing elements located posteriorly relative to the frontal plane of the tibial plate. The tibial plate may have two posterior stabilizing elements aligned in the midlateral direction and spaced apart by a linear distance varying according to the size of the tibial plate.

[0040] For example, the straight-line distance can be 24.7-50.7 mm, or 40.95% to 61.6% of the size of the tibial base plate.

[0041] The posterior stabilizing element can be located at 55% of the anteroposterior width of the substrate. This positioning helps minimize micromovement while reducing the risk of penetrating the posterior cortex of the tibia. In an alternative embodiment, the posterior stabilizing element may be misaligned.

[0042] The subsequent stabilizing element can be made entirely of porous material.

[0043] The tibial plate can have a shape symmetrical with respect to the central sagittal plane. Alternative embodiments can be asymmetrical with respect to the central sagittal plane.

[0044] Multiple porous portions can be distributed in a pattern beneath the substrate with optimal osseointegration and load transfer to the bone. These porous portions can define a pattern symmetrical with respect to the central sagittal plane.

[0045] The technical problems can also be solved using the methods discussed above for manufacturing tibial substrates, including layer-by-layer manufacturing of tibial substrates through additive manufacturing, such as EBM.

[0046] Technical issues can also be addressed by the tibial component of the knee prosthesis, which includes the tibial base plate discussed above and a support element adapted to be housed on the proximal surface of the tibial base plate.

[0047] At least one stabilizing element can be advantageously cut by an implant removal tool comprising a cutting guide adapted to guide a saw blade into the at least one stabilizing element and an adapter adapted to lock the implant removal tool onto the tibial plate; the adapter comprising a first adapter component and a second adapter component adapted to abut against a wall surrounding a proximal surface of the tibial plate defining the seat when the adapter is inserted into the seat; wherein the first adapter component and the second adapter component are movable away from each other in a direction parallel to the proximal surface, the first adapter component and the second adapter component abutting against the wall locking the adapter onto the tibial plate.

[0048] The second adapter component includes a second adapter component modular extension shaped to adapt to the adapter and fit a seat portion of a tibial plate of a defined size; the second adapter component modular extension may be replaced by another second adapter component modular extension adapted to a seat portion of a tibial plate of a different size.

[0049] By providing multiple modular extensions of the second adapter components, the implant removal tool can be adapted to tibial base plates of different sizes, shapes, and / or dimensions.

[0050] The adapter may also include adapter teeth designed to insert under the respective teeth of the tibial plate to retain the adapter within the seat. Advantageously, the teeth of the tibial plate may be the same as those used to retain the carrier element within the seat.

[0051] In other words, the implant removal tool can be fixed to the tibial base plate using the same features used to accommodate the carrier element.

[0052] The cutting guide can have a generally arched shape that follows the circular outline of the tibial plate, and more specifically, the anterior outline of the tibial plate.

[0053] The implant removal tool may include a sliding mechanism to move the first adapter component and the second adapter component relative to each other.

[0054] The sliding mechanism may include a lever, with one end of the lever hinged to the second adapter component, and another point of the lever being forced to translate relative to the first adapter component in a sliding direction orthogonal to the movement directions of the first and second adapter components.

[0055] In this way, the rotation of the lever in the first rotation direction moves the first adapter component and the second adapter component away from each other, and the rotation of the lever in the second rotation direction relative to the first rotation direction approaches the first adapter component and the second adapter component.

[0056] The implant removal tool may also include a locking mechanism for locking levers when the first adapter component and the second adapter component are inserted into the seat of the tibial base plate and maximally spaced apart from each other against a wall surrounding the proximal surface of the tibial base plate. In this way, the implant removal tool is securely locked in the tibial base plate to withstand the forces during the removal process and the vibrations of the saw blade in the cutting stabilizing element.

[0057] The locking mechanism includes an elastic element integrated with the lever. The elastic element can be designed such that when the lever rotates in the first rotational direction, it is received in a second groove of the first adapter component, and when the lever rotates fully in the first rotational direction, it is maximally compressed against a first second end of the second groove, with the first adapter component and the second adapter component maximally spaced apart from each other.

[0058] Therefore, during the cutting process of the stabilizing pin, the elastic element allows the first adapter component and the second adapter component to remain close to the wall of the substrate.

[0059] The elastic element may have a general U-shape, with the first elastic element end fixed at the first lever end and the second elastic element end fixed at the lever point between the first lever end and the second lever end.

[0060] Other features and advantages will become clearer from the following detailed description of exemplary, rather than exclusive, embodiments of the invention, with reference to the accompanying drawings, which are provided by way of example and not limitation thereof.

[0061] Brief description of the attached figures

[0062] Figure 1 A distal perspective view of a first embodiment of the tibial plate according to the present invention is shown;

[0063] Figure 2 It shows Figure 1 Rear view of the tibial plate;

[0064] Figure 3 It shows Figure 1 Side view of the tibial plate;

[0065] Figure 4 It shows Figure 1 A proximal perspective view of the tibial plate;

[0066] Figure 5 It shows Figure 1 A proximal view of the tibial plateau;

[0067] Figure 6 It shows along Figure 5 A cross-sectional view of the central sagittal plane of the tibial plate;

[0068] Figure 7 It shows the center of the stabilizing bolt. Figure 5 A cross-sectional view (CC) of the sagittal plane parallel to the tibial plate.

[0069] Figure 8 It shows the parallel to Figure 6 BB, a transverse cross-sectional view of the sagittal plane of the tibial plate.

[0070] Figure 9 A distal perspective view of the tibial component according to the present invention is shown;

[0071] Figure 10 It shows from Figure 9 A frontal view of the anterior aspect of the tibial component;

[0072] Figure 11 It shows Figure 9 Side view of the tibial component;

[0073] Figure 12 It shows along Figure 9 A cross-sectional view of the central sagittal plane of the tibial component;

[0074] Figure 13 It shows the relationship with Figure 9 A sagittal parallel section view of the tibial component (CC).

[0075] Figure 14 It shows the relationship with Figure 9 A transverse cross-sectional view BB parallel to the sagittal plane of the tibial component;

[0076] Figure 15 A proximal perspective view of a second embodiment of the tibial plate according to the present invention is shown;

[0077] Figure 16 It shows Figure 15 A proximal view of the tibial plateau;

[0078] Figure 17 It shows along Figure 16 A cross-sectional view of the central sagittal plane of the tibial plate;

[0079] Figure 18 It shows the connection with the passage Figure 16 A cross-sectional view BB of the sagittal plane parallel to the center of the stabilizing element of the tibia.

[0080] Figure 19 Three exemplary different sizes are shown. Figure 15 The proximal view and associated posterior view of the tibial plate;

[0081] Figure 20 A proximal perspective view of a third embodiment of the tibial plate according to the present invention is shown;

[0082] Figure 21 It shows Figure 20 A proximal view of the tibial plateau;

[0083] Figure 22 It shows Figure 20 Side view of the tibial plate;

[0084] Figure 23 It shows along Figure 21 A cross-sectional view of the central sagittal plane of the tibial plate;

[0085] Figure 24 It shows the connection with the passage Figure 21 A sagittal-plane parallel cut sectional view of the tibial plate of the stabilizing element (BB).

[0086] Figure 25 A diagram showing the cutting process is provided. Figure 1 A distant view of the implant removal tool for the stabilizing element of the tibial plate;

[0087] Figure 26 It shows Figure 25 A front view of the implant removal tool;

[0088] Figure 27 It shows Figure 25 A top view of the implant removal tool;

[0089] Figure 28 It shows Figure 25 A cross-sectional view of an implant removal tool along the central sagittal plane;

[0090] Figure 29 It shows Figure 25 Side view of the implant removal tool;

[0091] Figure 30 The second adapter component has been disassembled. Figure 25 A distant view of the implant removal tool;

[0092] Figure 31 It shows Figure 30 A front view of the implant removal tool;

[0093] Figure 32 It shows Figure 30 A top view of the implant removal tool;

[0094] Figure 33 It shows Figure 30 A cross-sectional view of an implant removal tool;

[0095] Figure 34 It shows Figure 30 Side view of the implant removal tool;

[0096] Figure 35 It shows the installation Figure 1 Tibial basement Figure 35 A distant view of the assembly, including the implant removal tool;

[0097] Figure 36It shows Figure 35 Front view of the assembly;

[0098] Figure 37 It shows Figure 35 A top view of the assembly;

[0099] Figure 38 It shows Figure 35 A cross-sectional view of the assembly;

[0100] Figure 39 It shows Figure 35 Side view of the assembly;

[0101] Figure 40 The closed configuration is shown. Figure 25 A distant view of the implant removal tool;

[0102] Figure 41 It shows Figure 40 Side view of the implant removal tool;

[0103] Figure 42 Extended configuration is shown Figure 25 A distant view of the implant removal tool;

[0104] Figure 43 It shows Figure 42 Side view of the implant removal tool;

[0105] Figure 44 The locking configuration is shown. Figure 25 A distant view of the implant removal tool;

[0106] Figure 45 It shows Figure 44 A side view of the implant removal tool. Invention Details

[0108] Referring to the accompanying drawings, exemplary embodiments of the tibial plate according to the present invention are generally identified by 1, 1' and 1”.

[0109] The terms “proximal,” “distal,” “superior,” “inferior,” “middle,” and “lateral” used in this instruction manual refer to the location of the tibial basement when implanted onto the proximal tibia in a known manner. More specifically, the term “proximal” means closer to the heart, and the term “distal” means further away from the heart. The term “inferior” means towards the foot, and the term “superior” means towards the head. The term “anterior” means towards the front part or face, and the term “posterior” means towards the back of the body. The term “middle” means towards the midline of the body, and the term “lateral” means away from the midline of the body.

[0110] Furthermore, planes are defined in known materials as follows: the frontal plane, perpendicular to the anteroposterior direction; the sagittal plane, perpendicular to the midlateral direction; and the transverse plane, perpendicular to the proximal-distal direction. The central sagittal plane is defined as the sagittal plane parallel to the center of the line passing through it, connecting the outermost point and the middle point (middle center of the tibial plate).

[0111] Specifically, the tibial base plate 1,1',1” is used in the non-cemented modular tibial component 200 of the knee prosthesis.

[0112] The tibial base plate 1 is designed to replace the proximal component of the tibia and is directly implanted into the previously transversely cut tibial platform, and a bearing element 100, such as a polymer liner, is received proximally, on which the femoral component of the knee prosthesis is hinged.

[0113] The tibial base plate 1 includes a large solid portion 2 having a shape symmetrical with respect to the central sagittal plane. The outer contour of the transverse plane of the large solid portion 2 is generally kidney-shaped and close to the outer transverse circumference of the cutting tibial plateau, and has a recess 50 in the central posterolateral position between the first condyle 51 and the second condyle 52 to accommodate the posterior cruciate ligament.

[0114] Alternative embodiments of the tibial lamina can have a shape asymmetrical relative to the central sagittal plane. See, for example... Figures 20-24 The tibial base plate 1 shown is a large solid portion 2 made of solid material and defined at the proximal end by a proximal surface 3 on which a support element 100 can be placed.

[0115] Large solid parts are made of a single material, more specifically, titanium or titanium alloys.

[0116] like Figure 1 As shown, the proximal surface 3, except for the recess 50, is defined by a perimeter wall 20 extending in the proximal direction. This perimeter wall 20 defines a seat 21 for receiving the carrier element 100. Together, the walls 20 lock the carrier element 100 to the proximal surface 3. Alternative embodiments with other types of locking mechanisms may be provided.

[0117] Extending from the central region 53 of the surface 3 toward the proximal end are positioning islands 24 for guiding the insert of the carrier element 100 into the seat portion 21. In an alternative embodiment, the islands 24 may be absent.

[0118] The perimeter wall 20 is provided with a holding method for fixing the bearing element 100 in the seat 21.

[0119] More specifically, the retention mechanism includes a first rear tooth 22a extending forward from the top of the wall 20, wherein the wall 20 defines a first condylar region 51 rearward, and a second rear tooth 22b extending forward from the top of the wall 20, wherein the wall 20 defines a second condylar region 52 rearward. The retention mechanism also includes a front tooth 22c extending rearward from the top of the front central member of the wall 20.

[0120] Figures 6 to 8 Different cross sections of the tibial base plate 1 are shown, in which retention methods 22a, 22b, and 22c are visible.

[0121] Figures 12 to 14 It shows Figures 6 to 8 The cross-section shows that the support element 100 is snapped into the seat portion 21 of the tibial base plate 1 and held by means of holding methods 22a, 22b, and 22c. As can be seen from these figures, the support element 100 is designed with engaging support element teeth 122a, 122b, and 122c below the corresponding teeth 22a, 22b, and 22c to be inserted into the tibial base plate 1, so as to hold the support element 100 in the seat portion 21.

[0122] The support element 100 is shaped to have concave surfaces 151, 152 corresponding to the condylar regions 51, 52, so as to adapt to the convex surface of the artificial condyle of the femoral component in a known manner. Other shapes of support element surfaces can be provided. Figure 9 and Figure 10 As shown, the frontal surface of the support element 100 is also provided with two pieces 101, which are adapted to remove the support element 100 from the seat portion 21.

[0123] Figure 4 and Figure 5 The bone contact surface 4 of the tibial plate 1 is shown opposite to the proximal surface 3, which is adapted to be placed in direct contact with the bone tissue of the cutting tibial plate.

[0124] Multiple porous portions 5 are seamlessly incorporated into the bulk solid portion 2 of the tibial substrate 1, which extend from the porous portion contact surface 6 into the bulk solid portion 2 at the bone contact surface 4.

[0125] The porous portion is made of a single material, and more specifically, it is identical to the bulk solid portion.

[0126] The presence of porous portion 5 reduces the overall stiffness of the tibial substrate. The stiffness and elasticity of the substrate may depend on, but not necessarily on, the thickness SP of the porous portion relative to the thickness SB of the bulk solid portion, as well as the number, size, and distribution of the porous portion 5 in the joint portion.

[0127] In one embodiment of the invention, the thickness SP of the porous portion is substantially half the thickness SB of the bulk solid portion (the calculation excludes walls 20 and jap 24, see example). Figure 8 (Example). For example, the thickness SB of the bulk solid portion is 2 mm and the thickness SP of the porous portion is 1.2 mm.

[0128] like Figure 4 and Figure 5 As shown, the porous portions 5 are distributed in a pattern symmetrical with respect to the central sagittal plane, and one is separated from the other by solid material of the bulk solid portion 2.

[0129] Specifically, the multiple porous portions 5 are separated from each other by the solid portions 401 of the bulk solid portions 2.

[0130] In other words, each porous portion is surrounded by a large solid portion of solid material, except for the porous portion contact surface 6 which is suitable for contacting bone tissue.

[0131] Each porous portion 5 is composed of a regular three-dimensional hexagonal cellular structure with a highly open interconnected porosity, mimicking the morphology of trabecular bone.

[0132] High porosity and sufficient pore size promote cell migration and vascularization, facilitate the transport of oxygen, nutrients, ions, and osteoinductive factors, and are beneficial for new bone formation. In other words, porosity promotes bone ingrowth or osteointegration, indicating a successful combination of osteoconduction and osteoinduction.

[0133] The porous portion 5 has a higher coefficient of friction on its contact surface 6 due to the roughness of the porous structure. The contact between the porous contact surfaces 6 enhances the primary stability of the implant and reduces micromovement. Together with the reduced stress shielding effect due to the substrate's stiffness adapting to physiological loads, this promotes bio-fixation (secondary stability), and the bone implants mechanically lock together.

[0134] Other embodiments of the tibial substrate may have porous portions 5 with different symmetry patterns. More specifically, this embodiment avoids placing the porous portion in the central region of the plate to improve its strength. For example, see... Figures 15 to 18 The tibial base plate 1' shown.

[0135] The tibial base plate 1 also includes stabilizing elements 30, 31 extending distally from the bone contact surface 4 and adapted to be inserted into the bone.

[0136] The tibial plate 1, 1', 1" according to the embodiment disclosed herein is provided with two types of stabilizing elements 30, 40 with different shapes:

[0137] - A pin 30 having a rounded tip 31 and a cross-sectional profile that is approximately six-pointed star-shaped; in other words, the pin 30 is an elongated pin with a concave hexagonal cross-section.

[0138] - A pointed object 40 with a sharp tip 41.

[0139] The pointed object 40 has a generally pyramidal shape with a concave, generally triangular base. At least one side of the triangular base is longer than the other sides. More specifically, as in... Figure 5 As can be seen, the base of the pyramid is basically an equilateral triangle, with its base positioned in front of the apex 41.

[0140] More specifically, the tibial base plate 1 is provided with two pins 30 located in positions symmetrical to the central sagittal plane relative to the tibial base plate 1, one corresponding to the first ankle region 51 and the other corresponding to the second ankle region 52.

[0141] In addition, pin 30 is closer to the rear side of the substrate.

[0142] Each pin 30 is made of, for example, the same porous material as the porous portion 5 and extends from the porous portion 5. Thus, the pin 30 is a protrusion of the porous portion 5 extending from the distal end of the porous portion contact surface 6.

[0143] The pins 30 are aligned in the mid-lateral direction. The straight-line distance between the pins 30 can vary depending on the size of the tibial plate.

[0144] Figure 19 Examples of three sizes of tibial base plates 1” with different distances between the pins 30 are shown. This can also be applied to other embodiments of tibial base plates.

[0145] The pin 40 is located in the central and anterior position, and its shape is symmetrical about the central sagittal plane relative to the tibial base plate 1.

[0146] Even though the pin 40 extends from the porous portion 5, where the base 42 is made of a porous material, the porous portion and the tip 41 are made of the same solid material as the bulk solid portion. The tip 41 is seamlessly integrated with the body base 42.

[0147] The tibial plate 1 according to the embodiments disclosed herein is made of a material, more particularly titanium or a titanium alloy.

[0148] The following describes an advantageous embodiment of an implant removal tool suitable for, for example, removing the tibial base plate 1 during a corrective surgery, cutting stabilizing elements 30, 40 extending distally from the bone contact surface 4 of the tibial base plate 1.

[0149] exist Figures 25-45In China, implant removal tools are typically identified by a 300 identifier.

[0150] The implant removal tool 300 includes an adapter 400, which is designed to hold the seat 21 of the tibial base plate 1 against the wall 20 surrounding the proximal surface 3.

[0151] More specifically, the adapter 400 includes mating adapter teeth 422a, 422b, 422c designed to be inserted below the teeth 22a, 22b, 22c of the tibial base plate 1, respectively, to retain the adapter 400 in the seat portion 21, as discussed below.

[0152] The adapter 400 includes a first adapter component 410 and a second adapter component 430.

[0153] The first adapter component 410 supports the cutting guide 301 of the implant removal tool 300 and is integrated with the first adapter component 410.

[0154] The second adapter component 430 is slidably connected to the first adapter component 410, allowing the first adapter component and the second adapter component to translate relative to each other in a sliding direction X parallel to the proximal surface 3 of the tibial base plate 3 when the adapter 400 is inserted into the seat 21.

[0155] Two pins 411 protrude from the first adapter component 410 and slide into the respective holes 413 of the second adapter component 430, guiding the relative translation of the first and second adapter components.

[0156] The second adapter component 430 further includes a second adapter component main element 431 and a removably coupled second adapter component modular extension 432. More specifically, the second adapter component main element 431 is provided with a hole 413 and is relatively movable relative to the first adapter component 410; the second adapter component modular extension 432 is coupled to the second adapter component main element 431 and is specifically shaped to abut against the wall 20 relative to the tibial base plate 1.

[0157] Advantageously, the modular extension 432 of the second adapter component can be provided in different sizes, each with a tibial plate 1 of various sizes. In this embodiment, the modular extension 432 of the second adapter component is coupled to the main component 431 of the second adapter component by means of a pin 414.

[0158] The aforementioned cutting guide 301 is adapted to guide the saw blade just below the bone contact surface of the tibial plate 1 to cut the attachment elements 30, 40 when the adapter 400 is inserted into the seat 21. The cutting guide opening is actually located on a plane just below the adapter 400.

[0159] The cutting guide 301 has a basic arched shape that follows the circular outline of the tibial base plate 1, and more specifically, the anterior outline of the tibial base plate 1.

[0160] The relative movement of the first adapter component 410 and the second adapter component 430 is actuated by the sliding mechanism 500.

[0161] The sliding mechanism 500 includes a lever 501 having a first lever end 502 hinged to the main element 431 of the second adapter component and a second lever end 503 opposite to the first lever end 502 that is freely actuated to rotate the lever 501.

[0162] A point 504 of lever 501 located between the first and second lever ends 502, 503 is coupled to the first adapter member 410 in a manner that restricts the translation of point 504 relative to the first adapter member 410 in the Y direction, which is orthogonal to the sliding direction X and parallel to the sliding plane of adapter members 410, 430. More specifically, at point 504 there is a slider 505 integrated with a lever that slides into a first groove 411 of the first adapter member 410 extending between the first groove end 411a and the second first groove end 411b.

[0163] Rotation of lever 501 in the first rotation direction D moves the first and second adapter components 410, 430 away from each other, and rotation of lever 501 in the second rotation direction S, opposite to the first rotation direction D, moves the first and second adapter components 410, 430 closer together (see...). Figure 42 When slider 505 is close to the second first groove end 411b, the rotation of lever 501 in the first rotation direction D stops, and when slider 505 is close to the first groove end 411a, the rotation of lever 501 in the second rotation direction S stops.

[0164] During its rotation, lever 501 is also inserted into a second groove 412 extending from the first second groove end 412a and the second second groove end 412b on a plane orthogonal to the sliding plane of adapter components 410 and 430 in the sliding direction X.

[0165] The implant removal tool 300 also includes a locking mechanism 600 for locking lever 501 when the first and second adapter components 410, 430 are spaced apart from each other to the maximum extent.

[0166] The locking method 600 includes an elastic element 601 fixed to the lever 501. For example... Figure 27As shown, the elastic element 601 has a substantially U-shaped shape, with a first elastic element end 601a fixed to a first lever end 502 and a second elastic element end 601b fixed to a second lever end 503. The elastic element 601 is sized to be received in a second groove 412 during lever rotation in the first rotation direction D, and to be maximally compressed in the second groove 412 when the lever 501 is fully rotated in the first rotation direction D. The slider 505 is close to the second first groove end 411b, and the first and second adapter parts 410, 430 are maximally spaced apart from each other.

[0167] The following is for reference. Figures 40 to 45 Description of the operation of tool 300 during a complete rotation in the first rotation direction D.

[0168] exist Figure 40 and Figure 41 The image shows a tool 300 in a closed configuration, with first and second adapter parts 410 and 430 in contact with each other, lever 501 fully rotating in the second rotation direction S, slider 505 abutting the first groove end 411a, and elastic element 601 mostly located outside the second groove 412.

[0169] Rotating lever 501 in the first rotation direction D causes the first and second adapter components 410 and 430 to gradually move away from each other, while slider 505 slides into first groove 411 and elastic element 601 enters second groove 412.

[0170] Figure 42 and Figure 43 The tool 300 is shown in an extended configuration, wherein the first and second adapter parts 410, 430 are spaced apart from each other to the greatest extent, and the elastic element 601 is uncompressed and partially within the second groove 412.

[0171] Starting with the tool 300 in a closed configuration, it is inserted into the wall 20 of the tibial base plate 1 below the corresponding teeth 22a, 22b of the insertion into the tibial base plate 1, in the seat 21 of the second adapter member 430 of the adapter 400, immediately abutting the wall 20 of the tibial base plate 1. Figures 37-41 As shown in the diagram. If the removal guide 300 is inserted into the tibial plate, the extension of the first adapter component 410 and the second adapter component 430 will be restricted due to contact with the wall 22 of the tibial plate. This restriction compresses the elastic element 601. This situation corresponds to the maximum compression of the elastic element 601.

[0172] If lever 501 continues to rotate in the first rotation direction D, the extension from adapter parts 410 and 430 will decrease without being inserted into the tibial plate.

[0173] When the removal guide is inserted into the tibial plate, the elastic element 601 is slightly depressurized, forcing the horizontal element 501 to continue rotating. This continuous rotation is limited by the end position 411b of the slot 505. Due to the compression of the elastic element 601, this end position securely locks the removal guide to the tibial plate, which exerts a compressive force on the wall of the tibial plate on one side and a force on the lever 501 in the first rotational direction on the other side.

[0174] Figure 44 and Figure 45 The tool 300 is shown in a blocking configuration, wherein the first and second adapter parts 410, 430 are spaced apart from each other, the lever 501 is fully rotated in the first rotation direction D, the slider 505 is abutted at the second first groove end 411b, and the elastic element 601 is maximally pressurized in the second groove 412.

[0175] In order to remove the obstruction of the guide from the tibial plate, a force of reverse rotation needs to be applied to lever 501, which requires compensating for the compressive force of the elastic element and moving lever 501 in the second rotation direction S.

[0176] Tibial base plates offer many advantages.

[0177] Advantageously, the disclosed tibial plate includes at least one porous portion that is seamlessly incorporated into a bulk solid portion without being joined between porous and solid materials.

[0178] The continuous transition between the bulk solid portion and the porous portion allows for greater structural strength and tensile strength of the tibial substrate compared to existing technologies that have an interface between porous and solid materials, which are structural weaknesses.

[0179] This integrated structure of the tibial substrate reduces the risk of delamination, peeling, and current effects typical of macro-rough coatings.

[0180] Advantageously, the tibial substrate of the present invention can be manufactured entirely by additive manufacturing methods, such as EBM.

[0181] The design of the tibial substrate has been optimized by accurately studying the thickness and distribution of the porous portion in the bulk solid part; as well as the effects of the location, material and number of stabilizing elements on micro-movement (i.e., the main stability of the implant) and load transfer to adjacent bones (i.e., stress shielding of the bones).

[0182] More specifically, in one particular study, a fluorescence study was conducted on patients with knee prostheses comprising a femoral component, tibial liner, and tibial plate to assess the biomechanics and kinematics of the prosthesis.

[0183] In parallel, a tibial model database was created based on patients who underwent total knee arthroplasty (TKA). This step was appropriate because bone databases typically only report the structure of healthy bone. However, the load transfer in healthy bone differs from that in patients who have undergone TKA. Using both inputs, a series of finite element simulations were performed on patients with prostheses of the same design and bone models with mechanical properties corresponding to the defects that lead to TKA, taking into account modular and monolithic tibial substrates in titanium with or without porous portions; different thicknesses, coefficients of friction, and distribution, shape, material, location, and stable attachment types of porous portions.

[0184] The final design of the aforementioned tibial plate is optimal for reducing micromovement and stress shielding, thereby achieving uniform stress distribution and low micromovement, and avoiding interference with the cortical bone of the stabilizing element to maintain the structural integrity of the bone without compromising stability.

[0185] More specifically, the tibial plate of the present invention has a modular type. This type is stiffer than the integral type, and therefore results in less micromovement.

[0186] Furthermore, advantageously, the tibial portion includes at least one porous portion with high friction and a thickness of at least 1.2 mm, which ensures the overall elasticity and stiffness of the tibial substrate, optimizes bone ingrowth conditions, and reduces micromovement.

[0187] The distribution of porous sections also contributes to the board's elasticity and stiffness, and can be optimized according to physical loads. The presence of solid material between the porous sections increases the overall structural strength of the board. More specifically, the location of the solid regions is chosen to maximize the static and fatigue strength of the substrate.

[0188] Simulation results indicate that the anteroposterior position of the stabilizing element has a greater impact than the mid-posterior position. Therefore, the tibial plate of this disclosure is provided with two pins located in the posterior region, almost at the center of the corresponding condyle. The posterior position also results in greater physiological load transfer.

[0189] In addition, the applicant defined the optimal straight-line distance between the two rear pins in the middle-rear direction for different substrate sizes. See the table below.

[0190] size #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 ML, in mm 24.7 27.9 31.3 34.7 38.4 42.2 46.1 49.6 50.1 50.7 ML, in % 40,95％ 44,3％ 47,7％ 50,8％ 53,9％ 56,8％ 59,6％ 61,6％ 59,8％ 58％

[0191] In addition, the applicant defined the optimal location of the posterior pin in the anteroposterior direction. More specifically, the posterior pin is located at 55% of the anteroposterior width of the base plate. This positioning helps to minimize micromovement while reducing the risk of penetrating the posterior cortex of the tibia.

[0192] The pins are made of porous material, which is believed to help reduce micro-movement and have better load transfer than solid pins.

[0193] It also advantageously provides at least one anterior stabilizing element to help reduce micromovements, and more particularly, anterior bulges caused by posterior loading. This is a pointed element, centrally located anteriorly, having at least one tip made of solid material to ensure full seating and thus allow bone ingrowth beneath the tibial plate.

[0194] Pins and points made of porous materials can also be easily cut using implant removal tools as described above.

[0195] The implant removal tool advantageously comprises a simple and compact structure that allows for rapid and efficient coupling to the tibial base plate and enables the stabilizing element to be cut in within seconds (less than 1 minute), creating small debris.

[0196] More specifically, the implant removal tool includes an adapter to be fixed to a seat of a tibial base plate having two components that can move relatively away from each other to abut against the peripheral wall of the seat.

[0197] The implant removal tool also advantageously includes a sliding mechanism and a locking mechanism to move the adapter components separately and lock them securely in the seat, while locking the implant removal tool in the tibial plate, allowing it to withstand the forces during the removal process and the vibrations of the saw blade in the cutting stabilizing element.

[0198] Obviously, those skilled in the art can apply various changes and modifications to the above invention to meet continuous and specific needs; however, all of these are within the scope of protection of the invention as defined by the appended claims.

Claims

1. A tibial base plate (1, 1', 1'') for the tibial component (200) of a knee prosthesis, comprising: - A large solid portion (2) comprising a proximal surface (3) adapted to accommodate a load-bearing element (100) for hinged to the femoral component of the knee prosthesis; - Multiple porous portions (5) to allow bone to grow inward, which are integrated with the bulk solid portion (2) and have porous portion contact surfaces (6) that are adapted to contact the proximal tibia opposite to the proximal surface (3); The plurality of porous portions (5) are seamlessly integrated into the bulk solid portion (2), wherein the plurality of porous portions (5) are embedded in the bulk solid portion (2). Furthermore, the tibial platelet (1, 1', 1'') is manufactured entirely by additive manufacturing. The plurality of porous portions (5) are separated from each other by solid portions (401) of the bulk solid portion (2), and each porous portion is surrounded by solid material of the bulk solid portion (2) except for the contact surface (6) of the porous portion suitable for contacting bone tissue.

2. The tibial substrate (1, 1', 1'') as claimed in claim 1, wherein the plurality of porous portions (5) have a thickness of 0.8 to 1.2 mm.

3. The tibial base plate (1, 1', 1'') as claimed in any one of claims 1 to 2, comprising at least one stabilizing element (30, 40) extending distally from the plurality of porous portions (5); the at least one stabilizing element (30, 40) being adapted to be inserted into the proximal tibia.

4. The tibial base plate (1, 1', 1'') as claimed in claim 3, wherein the at least one stabilizing element (40) is located in front of the tibial base plate (1) to reduce micromovement and prevent it from rising from the tibial base plate (1) due to posterior load during its implantation.

5. The tibial substrate (1) of claim 4, wherein the at least one stabilizing element (40) comprises a matrix (42) made of a porous material and a tip (41) made of a solid material; the solid material facilitates insertion into the proximal tibia and restricts bone ingrowth at the tip (41).

6. The tibial base plate (1') as claimed in claim 3, wherein for the frontal surface of the tibial base plate, two stabilizing elements (30) are located posteriorly and aligned in the mid-lateral direction; the two stabilizing elements (30) are spaced apart by a linear distance that varies according to the size of the tibial base plate.

7. The tibial substrate (1') as claimed in claim 6, wherein the two stabilizing elements (30) are located at at least 55% of the front-to-back width of the substrate.

8. The tibial substrate (1, 1', 1'') as claimed in claim 3, wherein the stabilizing element (30) is made entirely of a porous material.

9. The tibial base plate (1, 1') as claimed in claim 1, having a shape symmetrical with respect to the central sagittal plane.

10. The tibial base plate (1'') as claimed in claim 1, having a shape asymmetrical with respect to the central sagittal plane.

11. The tibial substrate (1, 1') as claimed in claim 1, wherein the plurality of porous portions (5) define a pattern symmetrical with respect to the central sagittal plane.

12. A method of manufacturing the tibial substrate (1, 1', 1'') according to any one of claims 1 to 11, comprising manufacturing the tibial substrate (1, 1', 1'') layer by layer by additive manufacturing.

13. The method of claim 12, comprising manufacturing the tibial substrate (1, 1', 1'') layer by layer by EBM.

14. The method of claim 12 or 13, wherein the tibial plate (1, 1', 1'') is made of titanium or a titanium alloy.

15. A tibial component (200) for a knee prosthesis, comprising a tibial base plate (1) according to any one of claims 1 to 11, and further comprising a support element (100) adapted to be received in a proximal surface (3) of the tibial base plate (1).

16. A component kit comprising a tibial base plate (1, 1', 1'') according to any one of claims 3 to 8 and an implant removal tool (300), the tibial base plate having a peripheral wall (20) defining a seat (21) surrounding the proximal surface (3), the implant removal tool being adapted to cut the at least one stabilizing element upon implantation of the proximal tibia for removal of the tibial base plate (1, 1', 1''), wherein the implant removal tool (300) includes a cutting guide (301) and an adapter (400), the cutting guide being adapted to guide a saw blade into the at least one stabilizing element, and the adapter (400) being retained to lock the implant removal tool (300) to the tibial base plate (1, 1', 1''). The cutting guide (301) on 1''); the adapter (400) includes a first adapter part (410) and a second adapter part (430) adapted to abut against the peripheral wall (20) when the adapter (400) is inserted into the seat (21); wherein the first adapter part (410) and the second adapter part (430) are capable of moving away from each other in a sliding direction (X) parallel to the proximal surface (3) so that the first adapter part (410) and the second adapter part (430) abut against the peripheral wall (20) so as to lock the adapter (400) to the tibial base plate (1, 1', 1'').

17. The component kit of claim 16, wherein the second adapter component (430) includes a second adapter component modular extension (432) shaped to fit the adapter (400) into a seat (21) of a defined size tibial plate (1, 1', 1''); the second adapter component modular extension (432) can be replaced by another second adapter component modular extension adapted to a seat of a different size tibial plate.

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