Modular artificial knee system

Abstract

The knee prosthesis moves between an extended position and a flexion position. The prosthesis includes a femoral component configured to be mounted to a femur, the femoral component having a femoral gear including a plurality of posts arranged along a helical trajectory. The prosthesis also includes a tibial component configured to (i) directly or indirectly mount to the tibia and (ii) engage the femoral component. The tibial component has a tibial gear that includes a plurality of recesses configured to engage with a post of the femoral gear. The tibial gear has two intersecting portions including a horizontally oriented curved portion and a vertical portion, where each portion includes at least one of the recesses. When the knee prosthesis is moved to an extended position, the plurality of posts follow a helical trajectory to cause movement of the tibial component in a medial or lateral direction.

Description

Technical Field

[0001] The present invention generally relates to artificial knee prostheses for total knee replacement (TKR), and more particularly, to knee prostheses having artificial anterior cruciate ligaments (ACLs) and / or posterior cruciate ligaments (PCLs). Background Art

[0002] As described in U.S. Patent Application Publication No. 2017 / 0252173 to Garino (incorporated herein by reference in its entirety and for all purposes), a prosthetic knee generally includes three main components: a femoral component (FIGS. 1A and 1B), which is attached to the distal end of the femur; a tibial baseplate (FIGS. 2A and 2B), which is implanted on the proximal end of the tibia; and an articulating tibial insert (FIGS. 3A and 3B), which mounts to the tibial baseplate and provides a friction surface for the femoral component. These components are designed to mimic the articulation and associated mechanics of the human knee throughout the knee's range of motion. These components are generally available in a variety of shapes with varying sizes (identified as sizes AH and JT in FIGs. 1A to 3B), enabling the physician to select the optimal combination of components depending on the patient's specific anatomy. The size and shape of the knee depend on various factors, including the patient's age, sex, and body type. Consequently, a substantial inventory of components is typically available, allowing the prosthetic knee to be customized for the patient.

[0003] During a conventional knee reconstruction using TKR, the ACL is removed in the vast majority of cases, and depending on the chosen TKR design, the patient's PCL is either preserved or replaced with some mechanism to replace the lost function of the PCL. Even when the PCL is preserved, a portion of the PCL must often be resected or partially resected during surgery to aid in the balance of the knee replacement. When the PCL is completely removed, it is replaced with a post and cam mechanism.

[0004] The TKR generally includes a femoral component 10, a tibial baseplate 16 having a post 18 that is implanted in a hole formed in the tibia, and an articulating insert 22 that resides on a top mounting portion 20 of the tibial baseplate 16 for interfacing with the femoral component 10. The articulating insert 22 can be separate from the tibial baseplate 16 as shown, or integrated as a single component with the tibial baseplate 16. The articulating insert 22 and the tibial baseplate 16 may be collectively or individually referred to herein as the "tibial component."

[0005] 1A , 1B , 3A , and 3B , an illustration of a typical design of a post and cam mechanism is provided. The joint insert 22 includes an extension 24 that projects into the opening 12 of the femoral component 10. A box 11 having upwardly projecting walls is formed on the interior side of the femoral component 10 and includes an interior area that intersects the opening 12. The extension 24 includes a posterior surface 25 that is intended to frictionally contact the posterior surface 14 of the opening 12 when the joint is flexed. The resistance generated when the extension 24 bears against the posterior surface 14 of the opening 12 in the femoral component 10 is intended to simulate the resistance that would be generated by a healthy posterior cruciate ligament (PCL).

[0006] A cam and post mechanism has been created to partially replace the function of the ACL by forming a cam surface between the anterior surface of extension 24 and the anterior surface of opening 12; however, this solution provides only partial replacement of the ACL because the anterior side of extension 24 can only contact the anterior side of the opening between 0 and 20 degrees of flexion under best circumstances.

[0007] The lack of an anatomically correct replacement may result in a TKR with reduced function compared to the original knee. This may create difficulties during physical therapy after surgery and limit the patient's ability or desire to participate in physical activities after treatment. Almost all modern total knee replacements sacrifice the ACL or inadequately replace it with a crude cam and post mechanism, resulting in a reconstructed knee with kinematics similar to that of a knee with an ACL deficiency. Therefore, normal knee kinematics remain elusive. Additionally, the lack of proper interaction between the ACL and PCL (which together drive normal knee motion) makes TKR reconstruction inadequate to produce a relatively normal knee for the patient.

[0008] Given the complexity of the mechanics of the knee joint and the difficulty patients have in adapting to artificial knees after surgery, there is a need for an anatomically correct knee replacement system that more accurately simulates the resilience and support previously provided by the removed ligaments. To provide a more anatomically correct TKR, a prosthetic embodiment that replicates the functions provided by both the ACL and PCL is ideal.

[0009] Referring now to FIG4 , a healthy human knee is illustrated with a loop 30 drawn over the locations of the native anatomical ACL and PCL, representing an exemplary artificial ACL / PCL ligament. The segment of loop 30 that constitutes the artificial PCL is bounded by points 26A and 26B. The segment of loop 30 that constitutes the artificial ACL is bounded by points 28A and 28B.

[0010] 5, 6A, and 6B, illustrating an embodiment disclosed in U.S. Patent Application Publication No. 2017 / 0252173 to Garino, the connection points 26a, 26b, 28a, and 28b of artificial material are provided as a ligament 44, and the segments spanning between the connection points provided as a contour of the artificial ligament 44 are configured to simulate the dimensions and attachment points of the ACL and PCL in a human knee, as illustrated in FIG4. At least one segment of the artificial ligament may be provided to connect the femoral component 10 and the articular insert 22 of a TKR.

[0011] While U.S. Patent Application Publication No. 2017 / 0252173 to Garino provides solutions to these complex issues, developments in this area are continually sought to improve the mechanics of the knee joint. Summary of the Invention

[0012] In one embodiment of the present invention, a knee prosthesis is configured to move between an extended position and a flexed position. The prosthesis includes a femoral component configured to be mounted to the femur, the femoral component having a femoral gear comprising a plurality of conical columns arranged along a spiral trajectory. The prosthesis also includes a tibial component configured to (i) be mounted directly or indirectly to the tibia, and (ii) engage the femoral component. The tibial component has a tibial gear comprising a plurality of recesses configured to engage with the conical columns of the femoral gear. The tibial gear has two intersecting portions comprising a horizontally oriented curved portion and a vertical portion, wherein each portion comprises at least one of the recesses. When the knee prosthesis is moved to the extended position, the plurality of conical columns follow the spiral trajectory to cause the tibial component to move in a medial or lateral direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 1A is a side view of a femoral component of a knee prosthesis known to those of ordinary skill in the art.

[0014] 1B is a bottom view of the femoral component of FIG. 1A .

[0015] 2A is a top view of a tibial component of a knee prosthesis known to those of ordinary skill in the art.

[0016] 2B is a side view of the tibial component of FIG. 2A .

[0017] 3A is a top view of a joint insert of a knee joint prosthesis known to those skilled in the art.

[0018] 3B is a front view of the articular insert of FIG. 3B mounted on a baseplate of a tibial component.

[0019] 4 is a side view of the knee joint illustrating the anatomical location of the ACL and PCL and the construction of artificial materials intended to replace the ACL and PCL.

[0020] 5 is a side view of a femoral component, joint insert, and artificial ligament for TKR according to the prior art.

[0021] FIG. 6A is a top view of a cross section taken along line II of FIG. 5 .

[0022] FIG6B is a bottom view of a cross section taken along line II of FIG5.

[0023] 7A is an assembled view of the modular knee prosthesis according to the first example, viewed from the top, left side, and back side.

[0024] 7B is an exploded view of the modular knee prosthesis of FIG. 7A .

[0025] Figure 7C to Figure 7F Depicted are side elevation, top plan view, posterior / rear elevation, and anterior / anterior elevation views, respectively, of the modular knee prosthesis of FIG. 7A .

[0026] FIG. 7G depicts a view taken along line 7G-7G. Figure 7F Cross-sectional view of a modular knee prosthesis, wherein the modular knee prosthesis is shown in an extended position.

[0027] 7H depicts another cross-sectional view of the modular knee prosthesis as in FIG. 7G , but wherein the modular knee prosthesis is shown in a flexed position.

[0028] 8A is an assembled diagram of a modular knee prosthesis according to a second example.

[0029] 8B is an exploded view of the modular knee prosthesis of FIG. 8A .

[0030] 8C-8F depict side elevation, top plan, posterior, and front elevation views, respectively, of the modular knee prosthesis of FIG. 8A.

[0031] 8G depicts a cross-sectional view of the modular knee prosthesis of FIG. 8F taken along line 8G-8G, wherein the modular knee prosthesis is shown in an extended position.

[0032] 8H depicts another cross-sectional view of the modular knee prosthesis as in FIG. 8G , but wherein the modular knee prosthesis is shown in a flexed position.

[0033] 8I depicts an exploded view of the modular knee prosthesis of FIG. 8A excluding the femoral bone, tibial bone, and tibial baseplate. DETAILED DESCRIPTION

[0034] The present invention provides various embodiments of the knee prosthesis. In the figures, "A" represents the anterior side or direction, "P" represents the posterior side or direction, "M" represents the medial side or direction, and "L" represents the lateral side or direction.

[0035] 7A to 7H depict a modular knee prosthesis 700 according to a first example, as described in U.S. Patent No. 11,419,731 to Garino. Although the prosthesis 700 is shown and described below for a left knee, it should be understood that a right knee prosthesis is substantially similar and the following explanations also apply to the right knee prosthesis.

[0036] The prosthesis 700 generally includes a modular femoral component 702 , a femoral insert 705 configured to be mounted to the femoral component 702 , a modular joint component 704 , and a tibial insert 706 configured to be mounted to the joint component 704 .

[0037] Modular femoral component 702 includes a U-shaped body having opposing condyles 710. A pin 711 extends upward from the medial surface of component 702 for implanting femoral component 702 into the femoral bone, as is known in the art. A rectangular cutout 712 is defined in femoral component 702 at a central location between condyles 710. Cutout 712 extends in an anterior-posterior direction and in the sagittal plane. Cutout 712 includes an opening at the posterior side of component 702. Cutout 712 extends through the entire wall thickness of component 702. Cutout 712 includes three interconnected and inwardly facing sides, namely, a lateral side extending in the sagittal plane, a medial side extending in the sagittal plane, and an anterior side connecting the lateral and medial sides. The posterior side of cutout 712 is open to receive insert 705.

[0038] A relief is formed on each of the opposing medial and lateral sides of the cutout 712. The reliefs together form a slot or track 713 that is configured to receive a rail 715 (i.e., a shoulder) formed on the opposing side of the femoral insert 705 so that the insert 705 can be mounted on the component 702. It should be understood that the track 713 can be provided on the insert 705 and the rail 715 can be provided on the component 702 to achieve the same or similar results.

[0039] It should be understood that means for mounting the insert 705 to the component 702 may be provided in addition to the tracks 713 and rails 715. Alternatively, the means for mounting may include slots, guides, rails, snap features, friction fits, interference fits, fasteners (screws, bolts, nuts), welds, adhesives, dovetails (or other mating surfaces).

[0040] Modular joint component 704 is configured to reside on a top mounting portion of a tibial component (not shown) for docking with femoral component 702. Joint component 704 is configured to be mounted to tibial baseplate 16 (see Figures 2B and 5), which is fixedly mounted to the tibia. Alternatively, and although not shown, joint component 704 can be integrated with tibial baseplate 16 to form a single, unitary tibial component that is fixedly mounted to the tibia. Thus, a "tibial component" can include joint component 704 (alone) or both joint component 704 and tibial baseplate 16.

[0041] The joint component 704 includes two concave surfaces 721 for physically engaging the convex condyle 710 of the femoral component 702 when the prosthesis 700 moves between a flexed position and an extended position. A rectangular cutout 723 is defined in the joint component 704 at a central location between the concave surfaces 721. The cutout 723 extends in an anterior-posterior direction and in the sagittal plane. The cutout 723 includes an opening at the posterior side of the joint component 704. The cutout 723 extends through the wall thickness of the joint component 704. The cutout 723 includes three interconnected and inwardly facing sides, namely, a lateral side extending in the sagittal plane, a medial side extending in the sagittal plane, and an anterior side connecting the lateral side and the medial side. A relief is formed on each of the opposing medial and lateral sides of the cutout 723. The reliefs together form a slot or track 724 that is configured to receive rails 725 (shoulders) formed on opposing sides of the tibial insert 706, such that the insert 706 can be mounted on the joint component 704 by sliding the rails 725 along the tracks 724. It should be understood that the tracks 724 can be provided on the insert 706 and the rails 725 can be provided on the joint component 704 to achieve the same or similar results.

[0042] It should be understood that means for mounting the insert 706 to the joint component 704 may be provided in addition to the tracks 724 and rails 725. Alternatively, the means for mounting may include slots, guides, rails, snap features, friction fits, interference fits, fasteners (screws, bolts, nuts), welds, adhesives, dovetails (or other mating surfaces).

[0043] The femoral component 702 and the joint component 704 are modular components common to the first to fourth embodiments. The femoral component 702 and the joint component 704 can together form a modular subassembly.

[0044] Turning now to the components that can be selectively mounted on those modular components 702 and 704, the femoral insert 705 is configured to be mounted to the femoral component 702, and the tibial insert 706 is configured to be mounted to the joint component 704 (or tibial component 704). The femoral insert 705 and the tibial insert 706 work together to guide the movement of the prosthesis 700 between the flexed and extended positions shown in Figures 7G and 7H.

[0045] The femoral insert 705 includes an L-shaped body. The body defines an elongated horizontal portion 731, from which rails 715 protrude from opposing side surfaces. The horizontal portion 731 is sized to fit snugly within the notch 712 of the femoral component 702. A vertical portion 733 of the body extends orthogonally from the horizontal portion 731. In assembled form, the vertical portion 733 lies flush with and bridges the condyles 710 of the femoral component 702. The vertical portion 733 also serves as a finger-like tab to facilitate manual insertion and / or removal of the insert 705 from the femoral component 702. The femoral insert 705 can be releasably or non-releasably connected to the femoral component 702.

[0046] Gears 734 in the form of convex surfaces protrude outwardly from the outwardly facing surfaces of the front and rear portions of the L-shaped body of the insert 705. Gears 734 include a plurality of individual gear teeth having rounded outer surfaces. The gear teeth are uniformly spaced along the outer periphery of the gear 734. As shown in FIG. 7D and FIG. Figure 7E As can be seen in FIG, gear 734 follows a helical path. Specifically, gear 734 rotates about (i) its own axis 740 extending in the medial-lateral direction (FIGS. 7G and 7H) and (ii) an axis extending in the anterior-posterior direction (see FIG. Figure 7E ) bend. In other words, the gear 734 bends along two different axes oriented orthogonally to each other. The gear 734 resides on the front and rear surfaces of the L-shaped body, while the rails 715 are provided on the left and right sides of the body, and the top-facing and rear-facing surfaces are planar. The femoral insert 705 can be a unitary, single-piece component.

[0047] The tibial insert 706 includes an elongated rectangular body. Rails 725 extend in the anterior-posterior direction and project from opposite side surfaces of the body. As described above, the rails 725 are sized to fit within the tracks 724 formed on the joint component 704, allowing the rails 725 to slide within their corresponding tracks 724. Finger-like tabs 744 are defined on the lower posterior edge of the insert 706 to facilitate manual manipulation of the insert 706. The tibial insert 706 can be releasably or non-releasably connected to the tibial component 704.

[0048] A curved channel 750 extends through the body of the insert 706 in an anterior-posterior direction. The channel 750 has opposing curved sidewalls that face each other. For example, as shown in FIG7B , the channel 750 curves about a vertical axis (in a superior-inferior direction or along the sagittal plane). The base surface of the channel 750 has a series of gear teeth 752 extending upwardly therefrom for engaging with the teeth of the gear 734. The base surface can be flat (except for the teeth 752), or the base surface can be curved about the axis 740 ( FIG7H ). The insert 706 can be a unitary, single-piece component.

[0049] Turning now to Figures 7G and 7H, the gear teeth 752 on the joint component 704 mesh with the gear teeth 734 of the femoral component 702, allowing the joint component 704 to rotate on the femoral component 702, or vice versa. When the femoral component 702 rotates in the posterior direction to the flexed position shown in Figure 7H (as indicated by the arrow), the meshing teeth do not slide past each other. Due to the curvature of the gear teeth 734 in the medial-lateral direction, the slight rotation of the joint component 704 in the medial-lateral direction when the prosthesis 700 moves between the flexed and extended positions mimics the slight rotation experienced in a real knee joint.

[0050] 8A to 8H depict a modular knee prosthesis 800 according to a second example. It should be understood that prosthesis 800 is similar to prosthesis 700, and only the major differences therebetween will be described hereinafter. Therefore, the details provided above with respect to prosthesis 700 also apply to prosthesis 800, unless otherwise explained hereinafter.

[0051] Prosthesis 800 includes a femoral component 802, an articular component 804, a femoral insert 805 (also referred to herein as a femoral gear), and a tibial insert 806 (also referred to herein as a tibial gear). FIG8I depicts an exploded view of prosthesis 800, in addition to a femoral bone 850, a tibial bone 852, and a tibial baseplate 854 (such as baseplate 16) for use with prosthesis 800. Tibial baseplate 854 may also be considered to form part of prosthesis 800.

[0052] Femoral component 802 is similar to femoral component 702, except that it includes vertical sidewalls 803 extending above rails 813. Articular component 804 is also similar to articular component 704, except that it includes rectangular recesses 824 on its bottom surface in place of rails such as rails 724. In assembled form, opposing tabs 825 extending in the lateral-medial direction on tibial insert 806 are inserted into recesses 824, thereby captivating articular component 804 to tibial insert 806.

[0053] Turning now to the femoral insert 805, the insert 805 comprises a hollow, semi-cylindrical body. Rails 815 extending in the posterior-anterior direction are disposed on opposing planar sidewalls of the body for engagement with tracks 813 of the femoral component 802. In the assembled configuration, as shown in FIG8A , the planar sidewalls of the body are supported and constrained in the medial-lateral direction by the sidewalls 803 of the femoral component 802. A series of gear teeth in the form of pegs 834 are disposed on the rounded rear face of the insert 805. As shown, each peg 834 has a frustoconical shape. Alternatively, each peg 834 may have a cylindrical, triangular, conical, rectangular, or trapezoidal shape (e.g., as viewed in cross-section). The free end surfaces of such cylindrical pegs may be flat or rounded. However, it was found that the frustoconical pegs 834 performed particularly well during testing, performing smoothly. The pegs 834 can be arranged along a spiral path, as shown in FIG8E , to mimic the motion of the knee (as described above with reference to the prosthesis 700). The spiral path is curved to drive rotation about the medial condyle, thereby forcing more translation of the lateral condyle as the knee flexes. Alternatively, the pegs 834 can be arranged along a linear path.

[0054] The pegs 834 can be uniformly spaced in a consistent manner, or they can be unevenly spaced. For example, to enhance the stability of the prosthesis, adjacent pegs 834 that are active (i.e., engaged) in the deep flexion position ( FIG. 8H ) of the prosthesis 800 can be positioned closer together than adjacent pegs 834 that are active in the extended position ( FIG. 8G ) of the prosthesis 800. Furthermore, the protrusion length, thickness, width, etc., of each peg 834 can be consistent or inconsistent. Specifically, adjacent pegs 834 that are active (i.e., engaged) in the deep flexion position ( FIG. 8H ) of the prosthesis 800 can have different protrusion lengths, thicknesses, widths, etc. than adjacent pegs 834 that are active in the extended position ( FIG. 8G ) of the prosthesis 800.

[0055] Turning now to the tibial insert 806, the insert 806 includes a generally L-shaped body including a horizontally oriented curved portion 817 and a generally vertical portion 819. The curvature of the horizontally oriented curved portion 817 can match the curvature of the curved surface of the femoral insert 805. The vertical portion 819 extends downward. The vertical portion 819 is configured so that the femoral insert can engage the tibial insert at a position far posterior to, and even slightly inferior to, the back of the tibia in the deep flexion state shown in FIG8H.

[0056] In the assembled state, the vertical portion 819 passes through a rectangular channel 855 ( FIG. 8I ) formed in the tibial baseplate 854. A series of concave recesses 820 are formed on the outer surface of the insert 806. The outer periphery of each recess 820 is substantially circular, except for recess 821 which has a teardrop-shaped outer periphery. The peripheral shape of recess 821 can also be described as elliptical. Recess 821 is formed at the intersection of portion 817 and portion 819. Recesses 820 / 821 can be arranged along a spiral path, as shown in FIG. 8B and FIG. 8E , to mimic the motion of the knee (as described above). Alternatively, recesses 820 / 821 can be arranged along a linear path. Although it has been found that the circular / elliptical shape of the recesses produces smooth kinematics for the prosthesis 800, it should be understood that the outer periphery of recesses 820 / 821 can vary and can take, for example, a rectangular, triangular, or trapezoidal shape.

[0057] It should be understood that the arrangement of the pegs and recesses can be reversed. In other words, the pegs 834 can be provided on the tibial insert 806 and the recesses 820 can be provided on the femoral insert 805.

[0058] Prosthesis 800 includes access openings in the tibial and femoral components, such as those represented by items 712 and 723, which enable the surgeon to access the intramedullary rod in the event of a fracture.

[0059] Although the femoral insert 805 is shown as a separate component, it can be formed as an integral component with the femoral component 802. Similarly, although the tibial insert 806 is shown as a separate component, it can be formed as an integral component with the articular component 804 or the tibial baseplate 854.

[0060] The geometry of the femoral and tibial inserts can vary. If desired, a plurality of different femoral and tibial inserts can be provided as a kit with one femoral component 802 and one joint component 804. In use, different femoral and tibial inserts can be selected by the surgeon based on various factors including, for example, the patient's age, sex, condition, and body type.

[0061] The parts of knee joint prosthesis can be made of identical or similar materials. However, in general, all materials are preferably inert, not easy to cause infection, and are otherwise safe and approved as surgical implants. Exemplary materials include polyethylene, surgically approved metal alloys, surgically approved ceramic materials or their combination. Any well-known material in the field of surgical implants can be used to manufacture any one according to various embodiments of the present invention or its part.

[0062] Although preferred embodiments of the present invention have been shown and described herein, it will be understood that such embodiments are provided as examples only. Without departing from the spirit of the present invention, those skilled in the art may conceive of many modifications, changes, and substitutions. Therefore, the appended claims are intended to cover all such modifications that fall within the spirit and scope of the present invention.

Claims

1. A knee prosthesis configured to move between an extended position and a flexed position, the modular knee prosthesis comprising: a femoral component configured to be mounted to a femur, the femoral component having a femoral gear comprising a plurality of posts arranged along a helical trajectory; as well as a tibial component configured to (i) be mounted directly or indirectly to a tibia and (ii) engage the femoral component, the tibial component having a tibial gear including a plurality of recesses configured to engage the post of the femoral gear, wherein the tibial gear has two intersecting portions including a horizontally oriented curved portion and a vertical portion, wherein each portion includes at least one of the recesses, Wherein, when the knee prosthesis is moved to the extended position, the plurality of posts follow a helical trajectory to cause the tibial component to move in a medial direction or a lateral direction.

2. The knee joint prosthesis according to claim 1, wherein: The femoral gear and the tibial gear are configured to mesh together in both the extended position and the flexed position.

3. The knee joint prosthesis according to claim 1, wherein: The plurality of recesses also follow a spiral trajectory to induce movement of the tibial component in the medial direction or the lateral direction when the knee prosthesis is moved to the extended position.

4. The knee joint prosthesis according to claim 1, wherein: The knee prosthesis is a modular knee prosthesis, wherein the femoral gear is a femoral insert removably mounted in a first cutout or opening defined in a central region of the femoral component, and wherein the tibial gear is a tibial insert removably mounted in a second cutout or opening defined in a central region of the tibial component.

5. The knee joint prosthesis according to claim 4, wherein: The femoral insert is removably mounted within the first cutout or opening of the femoral component via a rail and slot engagement.

6. A kit comprising the knee prosthesis according to claim 4, a plurality of different femoral gears and a plurality of different tibial gears.

7. The knee joint prosthesis according to claim 1, wherein: The femoral gear and the femoral component are formed as a unitary component.

8. The knee joint prosthesis according to claim 1, wherein: The tibial gear and the tibial component are formed as a unitary component.

9. The knee joint prosthesis according to claim 1, wherein: The tibial component is an articular component having a concave bearing surface shaped to engage the condyles on the femoral component.

10. The knee joint prosthesis according to claim 1, wherein The tibial component is a tibial baseplate configured to mount directly to the tibial bone.

11. The knee joint prosthesis according to claim 1, wherein: The femoral component includes opposing condyles, and the femoral gear and the tibial gear are positioned between the opposing condyles in a medial-lateral direction.

12. The knee joint prosthesis according to claim 1, wherein: The pillars each have a conical or frustoconical shape.

13. The knee joint prosthesis according to claim 1, wherein: The posts have different shapes, and the recesses have different shapes.

14. The knee joint prosthesis according to claim 1, wherein: The posts are not uniformly spaced.

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