Knee prosthesis and knee prosthesis assembly

Abstract

The application provides a knee joint prosthesis and a knee joint prosthesis assembly. The knee joint prosthesis comprises a tibial component, a liner and a femoral component. The tibial component comprises a platform and one or more convex ribs extending upwardly from an upper surface of the platform and forwardly from a posterior portion of the platform, a front edge of the upper surface of the platform is provided with at least one front boss, and a rear edge of the upper surface of the platform is provided with at least one rear boss. A lower surface of the liner has a groove matched with the convex ribs, a front cut groove matched with the front boss and a rear cut groove matched with the rear boss. The femoral component is articulately connected with an upper surface of the liner. At least one convex rib has an inner side wall and an outer side wall, one side wall of the inner side wall and the outer side wall has a bending portion and forms a first inclined surface in the forward extending direction, and the first inclined surface extends away from the other side wall.

Description

TECHNICAL FIELD

[0001] The present application relates generally to an implantable orthopedic prosthesis, and more particularly to a knee prosthesis and a knee prosthesis assembly. BACKGROUND

[0002] The concept of knee prosthesis design is generally based on the same principle, that is, to provide a similar biomechanical movement pattern to the normal knee joint by implanting knee joint components, and to obtain static and dynamic stability by balancing the implant itself and the knee ligaments and soft tissues. These knee joint component designs all try to restore the natural movement of the human knee joint, as well as adjust and control the forces generated during knee flexion and extension. However, none of the current knee prosthesis designs meets this standard.

[0003] Traditional knee prostheses mainly include a femoral component for coupling with the femur, a tibial component for coupling with the tibia, and a liner arranged on the upper surface of the tibial component. In a fixed liner type knee prosthesis, the liner cannot slide relative to the tibial component after being arranged on the tibial component.

[0004] In the prior art, a fixed groove is usually formed along the edge profile or central protrusion of the tibial component platform to guide or position, and a spring buckle is arranged in front of and behind the liner component to achieve the purpose of locking with the fixed groove.

[0005] However, in the use of the knee prosthesis, the force direction is mainly the front and back direction relative to the patient, so the forward shear force on the liner is greater than the left and right sides. As a result, the liner will have forward micro-motion, and frequent relative sliding will cause wear and tear. The locking structure in the above prior art is prone to cause stress concentration in the contact area between the liner and the tibial edge profile, resulting in insufficient locking force to offset the shear force of the forward movement of the liner, thereby increasing the amount of micro-motion of the liner and causing severe wear on the lower surface of the liner.

[0006] The above information disclosed in the background section is only intended to enhance the understanding of the background of the present application, and therefore it can include information that does not constitute the prior art known to those of ordinary skill in the art. SUMMARY

[0007] One main object of the present application is to overcome at least one of the above-mentioned defects of the prior art, and to provide a knee prosthesis that reduces the micro-motion of the liner.

[0008] Another main object of the present application is to overcome at least one of the above-mentioned defects of the prior art, and to provide a knee prosthesis assembly.

[0009] To achieve the above-mentioned objects, the present application adopts the following technical solutions:

[0010] According to an aspect of the present application, there is provided a knee prosthesis comprising a tibial component, a spacer and a femoral component. The tibial component comprises a platform and one or more ribs extending upwardly from an upper surface of the platform and forwardly from a posterior portion of the platform, a front edge of the upper surface of the platform is provided with at least one front boss, a posterior edge of the upper surface of the platform is provided with at least one posterior boss; a lower surface of the spacer has a groove matching the ribs, the spacer has a front cutout matching the front boss, the spacer has a posterior cutout matching the posterior boss; the femoral component articulates with an upper surface of the spacer; wherein at least one of the ribs has an inner sidewall and an outer sidewall, one of the inner sidewall and the outer sidewall has a bend and forms a first slope in a forward extending direction, the first slope extends away from the other of the inner sidewall and the outer sidewall.

[0011] According to an embodiment of the present application, the first slope forms an intersection line with the upper surface of the platform, an included angle between the intersection line and a central axis of the platform in a front-rear direction is greater than 0 degree.

[0012] According to an embodiment of the present application, the included angle is 2-70 degrees.

[0013] According to an embodiment of the present application, the ribs are a pair of ribs, the pair of ribs are arranged at a middle portion of the platform, at least one of the pair of ribs is parallel or at an angle to the central axis of the platform in the front-rear direction.

[0014] According to an embodiment of the present application, the bend has a notch extending upwardly from the upper surface of the platform and ending at an upper surface of the rib.

[0015] According to an embodiment of the present application, the other of the inner sidewall and the outer sidewall of the rib does not have the bend; or

[0016] the other of the inner sidewall and the outer sidewall of the rib has the bend and forms a second slope in the forward extending direction, the second slope is parallel or at an angle to the first slope.

[0017] According to an embodiment of the present application, the rib and the groove are in interference fit in a width direction.

[0018] According to an embodiment of the present application, the front boss has at least one front undercut, the posterior boss has at least one posterior undercut, the lower surface of the spacer has at least one front protrusion fitting into the front undercut and at least one posterior protrusion fitting into the posterior undercut.

[0019] According to an embodiment of the present application, the at least one posterior undercut is located at a middle portion of the posterior edge of the platform.

[0020] According to another aspect of the present application, there is provided a knee prosthesis assembly comprising one or more tibial components as described above, a plurality of liners as described above, and a plurality of femoral components. Each of the liners has a different width in the medial-lateral direction; and the femoral components articulate with the upper surfaces of the liners.

[0021] From the above technical solution, the knee prosthesis of the present application has the following advantages and positive effects:

[0022] The knee prosthesis provided by the present application has the following advantages and positive effects: the inner side wall and / or the outer side wall of the convex rib has a slope, and the groove also has a slope at the corresponding position; when the liner is subjected to a shear force in the forward direction, the convex rib and the groove are gapless at the slope matching position due to the slope matching of the convex rib and the groove, the convex rib effectively hinders the forward movement of the liner, and the occurrence of micromotion between the liner and the tibial component is significantly reduced; at the same time, according to the principle of trigonometric function, the slope of the convex rib will decompose the forward force of the liner into a part of force in a direction other than the forward direction, effectively reducing the size of the shear force of the liner in the forward direction and reducing the tendency of the liner to slide forward; accordingly, the slope matching of the convex rib and the groove effectively hinders the forward movement of the liner, reduces the micromotion of the liner, and effectively reduces the wear of the lower surface of the liner. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and other features and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[0024] Figure 1 is an exploded view of a knee prosthesis according to an exemplary embodiment.

[0025] Figure 2 is a top view of a tibial component according to an exemplary embodiment.

[0026] Figure 3 is a bottom view of a liner according to an exemplary embodiment.

[0027] Figure 4 is a rear view of the assembly of the tibial component and the liner according to an exemplary embodiment.

[0028] Figure 5 is Figure 4 is a sectional view along line A-A in FIG. 4.

[0029] Figure 6 is Figure 4 is a sectional view along line B-B in FIG. 4.

[0030] Figure 7is a perspective view of another embodiment of a tibial component according to an exemplary embodiment.

[0031] Figure 8 is a perspective view of yet another embodiment of a tibial component according to an exemplary embodiment.

[0032] Wherein the reference numerals are explained as follows:

[0033] 10 tibial component

[0034] 101 anterior edge

[0035] 102 posterior edge

[0036] 110 platform

[0037] 111 superior surface of the platform

[0038] 120 convex rib

[0039] 121 medial wall

[0040] 1211 first bevel

[0041] 122 lateral wall

[0042] 123 notch

[0043] 130 anterior boss

[0044] 1301 anterior undercut

[0045] 140 posterior boss

[0046] 1401 posterior undercut

[0047] 20 spacer

[0048] 201 superior surface of the spacer

[0049] 210 recess

[0050] 220 anterior slot

[0051] 2201 anterior protrusion

[0052] 230 posterior slot

[0053] 30 femoral component DETAILED DESCRIPTION

[0054] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations can be implemented in any number of manners, and are not limited to the example implementations described herein; rather, examples implementations should be understood as illustrative in nature. Like reference numerals refer to like elements throughout the various figures, and thus a detailed description thereof will not be repeated.

[0055] In the present application, the directions such as "front", "back", "upper", "lower", "inner", "outer" are consistent with the directions of the knee joint prosthesis after it is implanted into the human body when the person stands, and the present application is described by taking the knee joint prosthesis of the left knee as an example, for example, as shown in the figure, the right side of the tibial component is the inner side, and the left side of the tibial component is the outer side. Figure 2

[0056] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings, and the features described in the following embodiments can be combined with each other without conflict.

[0057] Figure 1 is an exploded view of a knee joint prosthesis according to an example embodiment. Figure 2 is a top view of a tibial component according to an example embodiment. Figure 3 is a bottom view of a spacer according to an example embodiment. Figure 4 is a back view of a tibial component and a spacer assembled according to an example embodiment. Figure 5 is a cross-sectional view along line A-A in Figure 4 Figure 6 is a cross-sectional view along line B-B in Figure 4 Figure 7 is a perspective view of another embodiment of a tibial component according to an example embodiment. Figure 8 is a perspective view of yet another embodiment of a tibial component according to an example embodiment.

[0058] As shown in the figure, the right side of the tibial component is the inner side, and the left side of the tibial component is the outer side. Figure 1 ​​​As shown, the present invention provides a knee joint prosthesis comprising a tibial component 10, a pad 20, and a femoral component 30. The tibial component 10 includes a platform 110 and a fixation member, such as an elongated rod, extending from the lower surface of the platform 110 in a direction away from the lower surface of the platform 110. The elongated rod can be implanted into the tibial end of a surgically prepared patient (not shown). The pad 20 can be fixed to the upper surface of the tibial component 10, for example, through the engagement of a rib 120 and a groove 210 as described below. The femoral component 30 can be implanted into the femoral end of a surgically prepared patient (not shown) and is constructed to mimic the natural femoral condyle configuration of the patient. The upper surface 201 of the pad 20 includes a lateral support surface and a medial support surface, which articulate with the lateral and medial condylar articular surfaces of the femoral component 30, respectively. Of course, as is well known to those skilled in the art, a patellar component may also be included, which will not be described in detail here.

[0059] The tibial component 10 and the femoral component 30 can be made of metals such as cobalt-chromium alloys, or other materials commonly used in the art. The bone-jointing surfaces of the tibial component 10 and the femoral component 30 can be textured to facilitate integration with the bone. Additionally, these bone-jointing surfaces can also have a porous coating to promote bone endophyseal growth, thereby achieving permanent fixation to the bone.

[0060] The gasket 20 may be made of polymeric materials, such as ultra-high molecular weight polyethylene, but is not limited to this.

[0061] The structure of the tibial component 10 and the pad 20 will be described in detail below with reference to the accompanying drawings.

[0062] like Figure 1 , Figure 2 and Figure 3 As shown, the tibial member 10 includes a platform 110 and one or more ribs 120 extending upward from the upper surface 111 of the platform 110 and forward from the rear edge 102 of the platform 110. The ribs 120 may be integrally formed with the platform 110, for example, by milling. The size of the platform 110 may conform to the outer contour shape of the patient's tibia after surgical removal of the apex portion, so that the lower surface of the platform 110 better engages with the cross-section of the patient's tibia.

[0063] In other embodiments of the invention, such as Figure 7 and Figure 8 As shown, one or more ribs 120 originate from the rear of the platform 110 and extend forward, without being connected to the rear edge 102 of the platform 110, as long as they can serve a guiding and positioning function.

[0064] The number of ribs 120 can be one, two, or more. At least one rib 120 has an inner wall 121 and an outer wall 122. In the direction in which the rib 120 extends forward, one of the inner wall 121 and the outer wall 122 has a bend and forms a first inclined surface 1211, which extends away from the other sidewall. The lower surface of the pad 20 has a groove 210 that matches the rib 120.

[0065] Specifically, for the sake of clarity in the following explanation, we will take an example where the inner wall 121 has a bend. For instance... Figure 2 As shown, the inner sidewall 121 extends forward and inward to form a first inclined surface 1211. The first inclined surface 1211 forms an angle with the rest of the inner sidewall 121. The inclined surface 1211 slopes inward in the forward extending direction, i.e., away from the outer sidewall 122. It should be noted that "away from the other sidewall" in this invention refers to the non-bent portion of the other sidewall. If the other sidewall also has a bent portion in the forward extending direction, then the inclined surface away from the other sidewall can be parallel to or even close to the bent portion of the other sidewall, forming approximately as shown in the diagram. or The shape. In other words, if the other sidewall has a bend in the forward extension direction, the present invention does not particularly limit the bending direction of the bend; the bending direction can extend outward or inward, or even as described above. The shape extends in the direction described above. It should be understood that all of the above-mentioned variations are within the protection scope of this invention.

[0066] Additionally, the upper surface 111 of platform 110 has at least one anterior boss 130 at its leading edge 101 and at least one posterior boss 140 at its trailing edge 102. Correspondingly, the liner 20 has an anterior groove 220 that matches the anterior boss 130 and a posterior groove 230 that matches the posterior boss 140. When the liner 20 is fixedly mounted on the upper surface 111 of platform 110 of tibial member 10, the anterior boss 130 may be accommodated in the anterior groove 220, and the posterior boss 140 may be accommodated in the posterior groove 230.

[0067] In this invention, it is not limited whether the inner wall 121 and the outer wall 122 of the protruding rib 120 are inclined in the vertical direction.

[0068] During use of the knee joint prosthesis, the force direction of the knee joint of the patient is mainly the front-back direction relative to the patient when the knee joint is flexed and extended, so the forward shear force on the liner 20 is greater than the medial and lateral sides, and thus the liner 20 will have forward micro-motion and wear caused by frequent relative sliding. The knee joint prosthesis provided by the present application has a structure design that one of the inner side wall 121 and the outer side wall 122 of the convex rib 120 has a bending portion and forms a first inclined surface 1211, and the first inclined surface 1211 extends away from the other side wall, so that the inner side wall 121 and / or the outer side wall 122 of the convex rib 120 has an inclined surface, and the groove 210 also has an inclined surface at the corresponding position. When the liner 20 is subjected to a forward shear force, the convex rib 120 and the groove 210 form an inclined surface matching, so that the convex rib 120 and the groove 210 are gapless at the inclined surface matching position, and the convex rib 120 effectively prevents the forward movement of the liner 20, significantly reducing the occurrence of micro-motion between the liner 20 and the tibial component 10. At the same time, according to the principle of trigonometric function, the inclined surface of the convex rib 120 will decompose the forward force on the liner 20 into a part of the force in a direction other than the forward direction, effectively reducing the size of the forward shear force on the liner 20, and reducing the tendency of the liner 20 to slide forward. Accordingly, the inclined surface matching of the convex rib 120 and the groove 210 effectively prevents the forward movement of the liner 20, reduces the micro-motion of the liner 20, and effectively reduces the wear of the lower surface of the liner 20.

[0069] Please continue to refer to Figures 1-3 In a preferred embodiment of the present application, the first inclined surface 1211 and the upper surface 111 of the platform 110 form an intersection line, and the intersection line and the central axis of the front-back direction of the platform 110 form an included angle greater than 0 degrees. For example, as shown in Figures 1 to 8 , the included angle can be 0-90 degrees, and as a preferred, the included angle can be 2-70 degrees. In addition, as described above , the shape of the included angle can also be 90-180 degrees.

[0070] Please continue to refer to Figures 1-3 In a preferred embodiment of the present application, the number of convex ribs 120 can be a pair, and the pair of convex ribs 120 is arranged at the middle of the upper surface 111 of the platform 110. The arrangement of the two convex ribs 120 makes the reaction force of the convex rib 120 to the liner 20 more uniform, stable and powerful.

[0071] In other embodiments, the pair of convex ribs 120 can be arranged symmetrically about the central axis of the platform 110 in the front-back direction.

[0072] It should be understood that the two convex ribs 120 described above can have substantially the same height or different heights. The term "substantially" is used to modify any relationship that can have minor variations, and there will be errors in measurement and assembly, but such errors will not change the nature.

[0073] In the present application, the convex rib 120 can be parallel to the middle axis of the platform 110 in the front-rear direction, or the convex rib 120 can be at an angle, for example, an acute angle, with the middle axis of the platform 110 in the front-rear direction. Of course, both of the convex ribs 120 can be parallel to the middle axis or at an angle with the middle axis, as long as the convex ribs can play a guiding role in the process of installing the prosthesis.

[0074] Referring to Figures 4-6 In a preferred embodiment of the present application, the bending portion of the convex rib 120 has a notch 123 extending upward from the upper surface 111 of the platform 110 and ending at the upper surface of the convex rib 120. The notch 123 prevents the sharp corner of the corresponding position of the groove 210 from interfering with the bending portion of the convex rib 120 when the convex rib 120 is assembled with the groove 210.

[0075] In the present application, the specific shape of the notch 123 is not particularly limited, for example, the cross-sectional shape of the notch 123 can be semicircular, rectangular, or other shapes that can accommodate the sharp corner of the groove 210 in the notch 123 without interference.

[0076] As Figure 2 shown, in a preferred embodiment of the present application, the other one of the inner side wall 121 and the outer side wall 122 of the convex rib 120 can not have the above-mentioned bending portion, in other words, the other one of the inner side wall 121 and the outer side wall 122 of the convex rib 120 can linearly extend from the rear edge 102 to the front edge 101 of the platform 110.

[0077] In another embodiment of the present application, the other one of the inner side wall 121 and the outer side wall 122 of the convex rib 120 has a bending portion in the forward extension direction and forms a second inclined surface, which can be parallel to the first inclined surface 1211 or at an angle. Specifically, taking the extension direction of the first inclined surface 1211 shown in Figure 2 as an example, the extension direction of the second inclined surface is described. In Figure 2 the first inclined surface 1211 extends forward and inward, the second inclined surface can be parallel to the first inclined surface 1211, i.e., extends forward and inward. Of course, the second inclined surface can also extend forward and outward.

[0078] As a preference, the second inclined surface can be symmetrically arranged with the first inclined surface 1211 with respect to the middle axis of the convex rib 120 in the front-rear direction, whereby each convex rib 120 and each groove 210 has two symmetrically arranged inclined surface mating surfaces when the spacer 20 is fixed to the tibial component 10, which more effectively hinders the forward sliding of the spacer 20 and reduces the wear of the lower surface of the spacer 20.

[0079] In one embodiment of the present invention, the rib 120 and the groove 210 may be interference-fitted in the inner and outer extension directions to prevent gaps in the inner and outer directions, thereby causing shaking.

[0080] like Figures 5 to 8 As shown, in one embodiment of the present invention, the front boss 130 has at least one front undercut 1301, the rear boss 140 has at least one rear undercut 1401, and the lower surface of the pad 20 has at least one front protrusion 2201 that engages with the front undercut 1301 and at least one rear protrusion that engages with the rear undercut 1401.

[0081] Accordingly, the cooperation between the rib 120 and the groove 210 can effectively prevent the pad 20 from moving relative to the tibial member 10 in the anterior / posterior direction and the medial / lateral direction, and the cooperation between the anterior undercut 1301 and the anterior protrusion 2201 and the posterior undercut 1401 and the posterior protrusion can effectively prevent the pad 20 from moving relative to the tibial member 10 in the upward direction.

[0082] The rib 120 extends from the rear to the front. During the installation of the pad 20, the rib 120 serves as an alignment and guide, allowing the groove 210 of the pad 20 to slide accurately along the rib 120 towards the rear edge 102. Specifically, the user can first align the groove 210 with the rib 120, then slide it rearward along the rib 120 until the rear protrusion engages with the posterior undercut 1401, and finally press down on the front of the pad 20 so that the rib 120 is completely accommodated within the groove 210, while the anterior protrusion 2201 engages with the anterior undercut 1301. Accordingly, the pad 20 is completely fixed to the tibial member 10, achieving locking in the anterior / posterior, medial / lateral, and vertical directions.

[0083] In one embodiment of the invention, at least one rear undercut 1401 is disposed at the middle of the rear edge 102 of the platform 110. For example, as Figure 7 As shown, the platform 110 has three rear bosses 140 on its rear edge 102. The rear boss 140 located in the middle of the rear edge 102 has a rear undercut 1401, while the other two rear bosses 140 may not have a rear undercut 1401. Correspondingly, the rear edge of the lower surface of the liner 20 has three rear grooves 230 that match the three rear bosses 140 respectively. The rear groove 230 located in the middle has a rear protrusion that matches the rear undercut 1401, while the other two rear grooves 230 may not have a rear protrusion.

[0084] The present invention also provides a knee joint prosthesis assembly, comprising one or more tibial members 10 of any of the above, a plurality of pads 20 of any of the above, and a plurality of femoral members 30, wherein the connection relationship between the three is the same as described above and will not be repeated here, wherein the plurality of pads 20 have different widths in the medial and lateral directions.

[0085] Knee prostheses are generally marketed in various sizes, and in particular in various widths, in order to adapt to the different sizes and bone configurations of patients in different populations. The knee prosthesis assembly provided by the present application takes into account the flexibility in size of the tibial component 10 and the spacer 20.

[0086] In particular, while the width of each of the plurality of spacers 20 in the medial-lateral direction can be different, the position and shape of the convex rib 120 and the anterior and posterior bosses and undercuts of each tibial component 10, as well as the position and shape of the groove 21 and the anterior and posterior slots and protrusions of each spacer 20, are constant, so that the mating relationship between the groove 210 of the spacer 20 and the convex rib 120 is constant. Accordingly, a plurality of spacers 20 of different widths can be secured to the same size tibial component 10, providing the surgeon with greater freedom in selecting different sizes of prosthetic components preoperatively and intraoperatively.

[0087] As described above, the various designs of the knee prosthesis and knee prosthesis assembly provided by the present application allow for improved interchangeability of different sizes of prosthetic components. In particular, any of a plurality of spacers 20 of different widths can be secured to the same size tibial component 10, which allows for reduced stocking of tibial components 10 in a knee prosthesis assembly stock, as well as the ability to select an appropriate size spacer 20 after implantation of a tibial component 10 intraoperatively.

[0088] It should be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the above description. The application is capable of other embodiments and of being practiced or being carried out in various ways. Variations and modifications of the foregoing are within the scope of the present application. It should be understood that the application fully encompasses all such variations and modifications that could result in a comparable result. It is the intention that the application be limited only by the scope of the appended claims.

Claims

1. A knee prosthesis, characterized in that Comprising: a tibial component comprising a platform and one or more ribs extending upwardly from an upper surface of the platform and forwardly from a posterior portion of the platform, a leading edge of the upper surface of the platform being provided with at least one leading boss, a trailing edge of the upper surface of the platform being provided with at least one trailing boss; a liner having a lower surface with grooves matching the ribs, the ribs and the grooves being interference fit in a width direction, the liner having a leading cutout matching the leading boss, the liner having a trailing cutout matching the trailing boss; and a femoral component articulating with an upper surface of the liner; wherein at least one of the ribs has an inner sidewall and an outer sidewall, one of the inner sidewall and the outer sidewall of the rib having a bend and forming a first slope extending away from the other of the inner sidewall and the outer sidewall of the rib, the bend having a notch extending upwardly from the upper surface of the platform and terminating at an upper surface of the rib. The first slope forms an intersection line with the upper surface of the platform, an included angle between the intersection line and a central axis of the platform in an anterior-posterior direction being greater than 0 degrees.

2. The knee prosthesis of claim 1, wherein, The included angle is 2-70 degrees.

3. The knee prosthesis of claim 2, wherein, The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being parallel to the central axis of the platform in the anterior-posterior direction.

4. The knee prosthesis of any of claims 1-3, wherein, The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being angled to the central axis of the platform in the anterior-posterior direction by an angle greater than 0 degrees.

5. The knee prosthesis according to any one of claims 1-3, wherein, The other of the inner sidewall and the outer sidewall of the rib does not have the bend.

6. The knee prosthesis of any of claims 1-3, wherein, The other of the inner sidewall and the outer sidewall of the rib has the bend and forms a second slope in a forward extending direction, the second slope being parallel to or angled to the first slope.

7. The knee prosthesis of any of claims 1-3, wherein, The leading boss has at least one leading undercut, the trailing boss has at least one trailing undercut, the lower surface of the liner has at least one leading protrusion engaging the leading undercut and at least one trailing protrusion engaging the trailing undercut.

8. The knee prosthesis of any of claims 1-3, wherein, The at least one trailing undercut is located at a middle portion of the trailing edge of the platform.

9. The knee prosthesis of claim 8, wherein, Comprising:

10. A knee prosthesis assembly, characterized by one or more tibial components as claimed in any of claims 1-9; a plurality of liners as claimed in any of claims 1-9, each of the liners having a different width in a medial-lateral direction; and a plurality of femoral components articulating with upper surfaces of the liners. wherein at least one of the ribs has an inner sidewall and an outer sidewall, one of the inner sidewall and the outer sidewall of the rib having a bend and forming a first slope extending away from the other of the inner sidewall and the outer sidewall of the rib, the bend having a notch extending upwardly from the upper surface of the platform and terminating at an upper surface of the rib. The first slope forms an intersection line with the upper surface of the platform, an included angle between the intersection line and a central axis of the platform in an anterior-posterior direction being greater than 0 degrees. The included angle is 2-70 degrees. The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being parallel to the central axis of the platform in the anterior-posterior direction. The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being angled to the central axis of the platform in the anterior-posterior direction by an angle greater than 0 degrees. The other of the inner sidewall and the outer sidewall of the rib does not have the bend. The other of the inner sidewall and the outer sidewall of the rib has the bend and forms a second slope in a forward extending direction, the second slope being parallel to or angled to the first slope. The leading boss has at least one leading undercut, the trailing boss has at least one trailing undercut, the lower surface of the liner has at least one leading protrusion engaging the leading undercut and at least one trailing protrusion engaging the trailing undercut. The at least one trailing undercut is located at a middle portion of the trailing edge of the platform. Comprising: one or more tibial components as claimed in any of claims 1-9; a plurality of liners as claimed in any of claims 1-9, each of the liners having a different width in a medial-lateral direction; and a plurality of femoral components articulating with upper surfaces of the liners. wherein at least one of the ribs has an inner sidewall and an outer sidewall, one of the inner sidewall and the outer sidewall of the rib having a bend and forming a first slope extending away from the other of the inner sidewall and the outer sidewall of the rib, the bend having a notch extending upwardly from the upper surface of the platform and terminating at an upper surface of the rib. The first slope forms an intersection line with the upper surface of the platform, an included angle between the intersection line and a central axis of the platform in an anterior-posterior direction being greater than 0 degrees. The included angle is 2-70 degrees. The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being parallel to the central axis of the platform in the anterior-posterior direction. The ribs are a pair of ribs, the pair of ribs being disposed at a middle portion of the platform, at least one of the pair of ribs being angled to the central axis of the platform in the anterior-posterior direction by an angle greater than 0 degrees. The other of the inner sidewall and the outer sidewall of the rib does not have the bend. The other of the inner sidewall and the outer sidewall of the rib has the bend and forms a second slope in a forward extending direction, the second slope being parallel to or angled to the first slope. The leading boss has at least one leading undercut, the trailing boss has at least one trailing undercut, the lower surface of the liner has at least one leading protrusion engaging the leading undercut and at least one trailing protrusion engaging the trailing undercut. The at least one trailing undercut is located at a middle portion of the trailing edge of the platform.

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