Cross-type knee replacement

Abstract

The present invention relates to a cross-replacement artificial knee. A knee prosthesis is capable of moving between an extended position and a flexed position. The knee prosthesis includes: a femoral component configured to be mounted to a femur; a tibial component configured to be mounted to a tibia; a column fixedly connected to one of the femoral component and the tibial component; and a contoured recess defined on the other of the femoral component and the tibial component, the contoured recess configured to be engaged by the column in an extended position or a flexed position of the knee prosthesis. The knee prosthesis may also include an artificial ligament extending between the femoral component and the tibial component. The column and the ligament mimic one of the ACL and the PCL.

Description

Technical Field

[0001] The present invention generally relates to artificial knee prostheses for total knee replacement (TKR), and more particularly to a knee prosthesis having an artificial anterior cruciate ligament (ACL) and / or posterior cruciate ligament (PCL). Background Art

[0002] As described in U.S. Patent Application Publication No. 2017 / 0252173 to Garino (which is incorporated herein by reference in its entirety and for all purposes), a prosthetic knee generally includes three major components: a femoral component ( Figure 1A and 1B ), which is attached to the distal end of the femur; the tibial component ( Figure 2A and 2B ), which is implanted on the proximal end of the tibia; and an articular insert ( Figure 3A and 3B ), which is mounted to the tibial component and provides a friction surface for the femoral component. The components are designed to simulate the joint and associated mechanical structure of the human knee throughout the full range of motion of the knee. The components are generally available in different sizes (in Figures 1A to 3B The knee is provided in a variety of shapes (identified as sizes AH and JT) so that the physician can select the best combination of components depending on the patient's specific anatomy. The size and shape of the knee depends on a variety of factors including the patient's age, gender, and size. Thus, a relatively large inventory of components is generally available so that the prosthetic knee can be customized for the patient.

[0003] During a course of conventional knee reconstruction with TKR, in the vast majority of all cases and depending on the TKR design selected, the ACL is removed and the patient's PCL is either preserved or replaced with some mechanism to replace the function lost by the PCL. Even when the PCL is preserved, portions of the PCL must often be resected or partially resected during surgery to assist in balancing the knee replacement. When the PCL is completely removed, it is replaced by a mechanism of posts and cams.

[0004] The TKR generally includes a femoral component 10, a tibial component 16, and an articular insert 22, which is present on a top mounting portion 20 of the tibial component 16 for interfacing with the femoral component 10. Figure 1A , 1B, 3A and 3B, provide illustrations of typical designs of the mechanisms of the posts and contours. The joint insert 22 includes an extension 24 that protrudes into the opening 12 of the femoral component 10. A box 11 with an upwardly projecting wall is formed on the medial side of the femoral component 10 and includes an interior area that intersects the opening 12. The extension 24 includes a rear surface 25 that is intended to be in frictional contact with the rear surface 14 of the opening 12 when the joint is flexed. The resistance generated when the extension 24 is pressed against the rear 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).

[0005] Contour and post mechanisms have been made that partially replace the function of the ACL by forming a contoured surface between the anterior surface of the extension 24 and the anterior surface of the opening 12; however, this solution only provides a partial replacement of the ACL because the anterior side of the extension 24 can only contact the anterior side of the opening at most between 0 and 20 degrees of flexion.

[0006] Another solution is to connect the femoral component to the tibial component using a cable-like material, such as that disclosed in U.S. Pat. No. 5,935,133, the contents of which are incorporated herein by reference. However, this artificial material is typically only used to replace the PCL and not the ACL.

[0007] The lack of an anatomically correct replacement can result in a TKR with reduced functionality compared to the original knee. This can create difficulties during physical therapy following surgery, as well as limiting the patient's ability or desire to participate in physical activities following treatment. Virtually all modern total knee replacements sacrifice the ACL or utilize a crude contour and post mechanism to improperly replace the ACL, thus resulting in the reconstructed knee having kinematic properties similar to those of a knee lacking the ACL. Thus the kinematic properties of a normal knee remain elusive. Additionally, the lack of proper interaction between the ACL and PCL (which together drive the kinematic properties of a normal knee) results in TKR reconstructions falling short of producing a relatively normal knee for the patient.

[0008] Given the complexity of the mechanical structure of the knee joint and the difficulty for patients to adapt to an artificial knee after surgery, there is a need for an anatomically correct knee replacement system that more accurately simulates the flexibility and support previously provided by the removed ligaments. In order to provide a more anatomically correct TKR, a prosthetic embodiment that replicates the functions provided by both the ACL and PCL is desirable.

[0009] Reference now Figure 4, a healthy human knee is shown with a ring 30 representing an exemplary artificial ACL / PCL ligament, the ring 30 being drawn over the location of the original anatomical ACL and PCL. The section of the ring 30 constituting the artificial PCL is bounded by points 26A and 26B. The section of the ring 30 constituting the artificial ACL is bounded by points 28A and 28B.

[0010] Reference is now made to the embodiments disclosed in U.S. Patent Application Publication No. 2017 / 0252173 to Garino. Figure 5 , 6A and 6B, the connection points 26a, 26b, 28a and 28b of the artificial material provided as the ligament 44 and the length across the connection points provided as the profile of the artificial ligament 44 are constructed to simulate the Figure 4 The dimensions and attachment points of the ACL and PCL in a human knee are shown in FIG. At least one length of artificial ligament may be provided to connect the articular insert 22 and the femoral component 10 of the TKR.

[0011] While U.S. Patent Application Publication No. 2017 / 0252173 to Garino provides solutions to these complexities, developments in this area continue to be sought to improve the mechanics of the knee joint. Summary of the invention

[0012] In one embodiment of the present invention, a knee joint prosthesis is capable of moving between an extended position and a flexed position. The knee joint prosthesis includes a femoral component configured to be mounted to the femur and a tibial component configured to be mounted to the tibia, and the tibial component is configured to engage with the femoral component to form a knee joint prosthesis. A first column is fixedly connected to one of the femoral component and the tibial component, and a first contoured recess is limited on the other of the femoral component and the tibial component, and the first contoured recess is configured to be engaged by the first column in the extended position or the flexed position of the knee joint prosthesis. A second column is fixedly connected to one of the femoral component and the tibial component, and a second contoured recess is limited on the other of the femoral component and the tibial component, and the second contoured recess is configured to be engaged by the second column in the extended position or the flexed position of the knee joint prosthesis.

[0013] In another embodiment of the present invention, a kind of knee joint prosthesis comprises the femoral component that is configured to be installed to femur and the tibial component that is configured to be installed to tibia, and the tibial component is configured to engage with the femoral component, to form the knee joint prosthesis.Post is fixedly connected to one in femoral component and the tibial component, and the contoured recess is limited on another in femoral component and the tibial component, and is configured to be engaged by the first post in the extended position or the flexed position of the knee joint prosthesis.Artificial ligament is fixedly connected to femoral component and the tibial component, to simulate anterior cruciate ligament or posterior cruciate ligament.As seen in sagittal plane, frontal plane or sagittal plane and frontal plane, post and ligament are oriented in a cruciate shape.

[0014] In another embodiment of the present invention, a knee prosthesis includes a femoral component configured to be mounted to the femur and a tibial component configured to be mounted to the tibia. The tibial component is configured to engage the femoral component to form the knee prosthesis. The femoral component and the tibial component are at least partially connected together by a gear transmission assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A is a side view of a femoral component for a knee prosthesis known to those of ordinary skill in the art.

[0016] Figure 1B yes Figure 1A Bottom view of the femoral component.

[0017] Figure 2A is a top view of a tibial component for a knee prosthesis known to those of ordinary skill in the art.

[0018] Figure 2B yes Figure 2A Side view of the tibial component.

[0019] Figure 3A is a top view of a joint insert for a knee joint prosthesis known to those skilled in the art.

[0020] Figure 3B It is mounted on the base of the tibial component. Figure 3B Front view of the joint insert.

[0021] Figure 4 is a side view of the knee joint showing the anatomical location of the ACL and PCL and the construction of artificial materials intended to replace the ACL and PCL.

[0022] Figure 5 is a side view of a femoral component, a joint insert, and an artificial ligament for TKR according to the prior art.

[0023] Fig. 6A It is along Figure 5Top view of the cross section along line II.

[0024] Figure 6B It is along Figure 5 Bottom view of the cross section along line II.

[0025] Fig. 7A is a cross-sectional side view of a knee prosthesis according to an exemplary embodiment of the present invention as seen in the sagittal plane, wherein the knee prosthesis is shown in an extended position.

[0026] Figure 7B yes Fig. 7A Another view of a knee prosthesis of , wherein the knee prosthesis is shown in a flexed position.

[0027] Figure 8 An alternative embodiment of a knee prosthesis is depicted as viewed in the sagittal plane, wherein a post is disposed on the femoral portion and a contour is disposed on the tibial portion.

[0028] Fig. 9 An alternative embodiment of a knee prosthesis is depicted as seen in the sagittal plane, wherein one post and one contour are provided on each of the femoral and tibial components.

[0029] Fig. 10A Depicted is a partial cross-sectional view of an embodiment of a knee prosthesis as seen in the sagittal plane, wherein a post mimicking the ACL and PCL is disposed on the tibial portion and engages with a contoured portion on the femoral portion.

[0030] Fig. 10B Depicts the frontal plane as seen Fig. 10A of knee prosthesis.

[0031] Fig.11 An alternative embodiment of a knee prosthesis is depicted as seen in the sagittal plane, wherein a post mimicking the ACL and PCL is disposed on the femoral portion and engages with a contoured portion on the tibial portion.

[0032] Fig.12 An alternative embodiment of a knee prosthesis is depicted as seen in the sagittal plane, wherein a post mimicking the PCL is disposed on the tibial portion and engages a contoured portion on the femoral portion, and an artificial ligament mimicking the ACL is disposed between the tibial and femoral portions.

[0033] Fig.13 An alternative embodiment of a knee prosthesis is depicted as seen in the sagittal plane, wherein a post mimicking the ACL is disposed on the tibial portion and engages with a contoured portion on the femoral portion, and an artificial ligament mimicking the PCL is disposed between the tibial and femoral portions.

[0034] Fig.14 An alternative embodiment of a knee prosthesis is depicted as seen in the sagittal plane, wherein posts mimicking the ACL and PCL are disposed on the tibial portion and engage with contours on the femoral portion.

[0035] Fig.15A and 15B Depicted is a side view of an alternative embodiment of a knee prosthesis as seen in the sagittal plane, wherein the tibial portion is coupled to the femoral portion via a gear drive assembly. Fig.15A is shown in the extended position and in Fig. 15B Shown in a flexed position.

[0036] Fig.16A Depicted is a side view of an alternative embodiment of a knee prosthesis as seen in the sagittal plane, wherein the tibial portion is coupled to the femoral portion by a gear assembly, and the gear assembly is configured to move the tibial portion medially after rotation to an extended position. Fig. 16B The knee joint is shown from the back and Fig. 16C The knee joint is shown from the front.

[0037] Fig.17 An alternative embodiment of a knee prosthesis is depicted as viewed in the sagittal plane, wherein the tibial portion is coupled to the femoral portion by an assembly of a post and contour.

[0038] Fig.18 An alternative embodiment of a knee prosthesis is depicted as viewed in the sagittal plane, wherein the tibial portion is coupled to the femoral portion by an assembly of a post and contour.

[0039] Fig.19 is a plan view depicting an alternative embodiment of a knee prosthesis in which the tibial component is coupled to the femoral component by a pin and slot assembly. DETAILED DESCRIPTION

[0040] The present invention provides various embodiments of knee prostheses. In the accompanying drawings, 'A' indicates the anterior or forward direction, 'P' indicates the posterior or rearward direction, 'M' indicates the medial or inward direction, 'L' indicates the lateral or outward direction, 'F' indicates the femoral component, and 'T' indicates the tibial component (or an articular insert forming part of the tibial component).

[0041] Fig. 7A is a cross-sectional side view of a knee prosthesis 100 according to an exemplary embodiment of the present invention as seen in the sagittal plane, wherein the knee prosthesis 100 is shown in an extended position. Figure 7B yes Fig. 7AAnother view of the knee prosthesis 100, wherein the knee prosthesis 100 is shown in a flexed position. The knee prosthesis 100 can be Fig. 7A The stretched position and Figure 7B Rotation between flexed positions.

[0042] The prosthesis 100 generally includes a femoral component 102 and an articular insert 104 that is mounted to or forms part of a tibial component.

[0043] Fig. 7A and 7B The femoral component 102 shown in the figure may represent a femoral component (such as article 10) having condyles or a box (such as box 11) mounted to the femoral component. A recess 108 is formed on the lower end of the femoral component 102. The recess 108 is located between the condyles 106 along the inner and outer directions. An edge 111 is formed at the semicircular boundary of the recess 108 at the position where the recess 108 intersects with the outer surface of the femoral component 102. The recess 108 is positioned at the same approximate position as the opening 12 in the femoral component 10. However, unlike the opening 12, the recess 108 is blind at one end and includes a smooth and rounded inner surface. Two contoured surfaces 110a and 110b (which are individually or collectively referred to as (one or more) contoured surfaces 110) are formed at opposite ends of the inner surface of the recess 108. Each contoured portion 110 is a smooth and rounded concave surface. The radii of the contoured portions 110 may be the same or different. The contoured portions 110 are configured to interact with rounded posts 112a and 112b extending from the top surface of the articular insert 104.

[0044] The joint insert 104 is similar to the joint insert 22, and the main differences between those inserts will be described below. The joint insert 104 includes two columns 112a and 112b (which are individually or collectively referred to as (one or more) column surfaces 112) extending from a load-bearing surface 113. The column 112a corresponds to the ACL, while the column 112b corresponds to the PCL. Each rounded column 112 terminates at a convex rounded surface. The radius of each column 112 can be equal to the radius of each contoured portion 110, or substantially the same as the radius of each contoured portion 110. The extension height and radius of the column 112 can be different (as shown) or the same, to complement the geometry of the matching contoured portion 110. According to this embodiment, the ACL column 112a has a higher height than the PCL column 112b. The column 112 extends along its respective axis Z, which is orthogonal to the load-bearing surface 113. Alternatively, the column 112 can extend obliquely relative to the axis Z. Fig. 7AThe post 112, as well as all other posts described herein, may be integral to the joint insert 22 (or other component to which the post is connected) as shown, or may be connected to the joint insert 22 using mechanical threads, bolts, friction, adhesives, glues, or any other means known to those skilled in the art for mounting two components together.

[0045] The joint insert 104 can be positioned relative to the femoral component 102. Fig. 7A The stretched position and Figure 7B 104 and the flexed position. In the extended position of the knee prosthesis 100, the condyles can be placed on the load-bearing surface 113 of the joint insert 104, and the posts 112 are positioned against their corresponding contours 110. When the femoral component 102 rotates relative to the joint insert 104 or vice versa, the posts 112 ride along the surface of the contours 110 until the edge 111 of the recess 108 presses against the base of the posterior column 112. The ACL post 112a can press against its contour 110a. Although not shown, the collateral ligaments (MCL and LCL) adjacent to the knee prosthesis 100 prevent the femoral component 102 from separating from the joint insert 104.

[0046] The assembly of two posts 112 and two contours 110 more closely mimics the assembly of the PCL and ACL than conventional knee prostheses having a single post and a single contour.

[0047] As noted above, recess 108 may be formed in a separate insert (such as cartridge 11) that can be attached to femoral component 102. A series of inserts having different recess geometries may be provided as a kit so that a medical professional can select an insert having a geometry that best suits a patient's specific anatomy.

[0048] Figure 8 A knee prosthesis 118 is depicted in which posts 122a and 122b are disposed on a femoral component 124 and a contoured portion 128 is defined in a recess 130 disposed on an articular insert 132 of a tibial component. The knee prosthesis 118 is similar to the knee prosthesis 100 except that the positions of the posts and the contoured portions are swapped. The operation of the knee prosthesis 118 is substantially similar to that of the knee prosthesis 100. Although not shown, posts 122a and 122b may be formed in a separate insert that can be attached to the femoral component 124, as in the case of the box 11.

[0049] Fig. 9 A knee prosthesis 136 is depicted. The knee prosthesis 136 is similar to the knee prosthesis 100, except that a post 138 and a contoured recess 140 are provided on a femoral component 142, and a post 144 and a contoured recess 146 are provided on an articular insert 148 of a tibial component. Fig. 9 140, the post 144 of the tibial articular insert 148 is mounted using the contoured recess 146 of the tibial articular insert 148, and the post 144 of the tibial articular insert 148 is mounted using the contoured recess 140 of the femoral component 142. Although the post 138 is disposed in front of the recess 140, it should be understood that the positions of the post 138 and the recess 140 can be interchanged (along with the positions of the recess 146 and the post 144). The operation of the knee prosthesis 136 is substantially similar to the operation of the knee prosthesis 100.

[0050] Fig. 10A and 10B An embodiment of a partial cross-sectional view of a knee prosthesis 150 is depicted. Prosthesis 150 is similar to prosthesis 100, and only the major differences therebetween will be described. In knee prosthesis 150, posts 152a and 152b (collectively referred to as posts 152) that more closely mimic the PCL and ACL, respectively, are disposed on an articular insert 154 of the tibial portion (or the tibial portion itself), and are engaged with contoured portions 156a and 156b (collectively referred to as contoured portions 156) disposed on recessed portions 157 formed on femoral component 158, respectively. Recessed portions 157 extend upwardly from a load-bearing surface 155 of prosthesis 150.

[0051] Specifically, the post 152a extending from the lateral posterior side of the joint insert 154 to the medial anterior side of the femoral component 158 ​​more closely mimics the location and geometry of the PCL. The post 152b extending from the medial anterior side of the joint insert 154 to the lateral posterior side of the femoral component 158 ​​more closely mimics the location and geometry of the ACL. The posts 152a and 152b are oriented in a cruciate shape as seen in the sagittal and frontal planes, however, the posts 152a and 152b may be oriented in a cruciate shape as seen in only one of those planes.

[0052] As seen in the sagittal plane, the angle 'B' of each column 152 relative to the bearing surface 155 may be different from the angle shown and can be customized to approach the exact angle of the ACL or PCL. Similarly, as seen in the frontal plane, the angle 'D' of each column 152 relative to the bearing surface 155 of the joint insert 154 may be different from the angle shown and can be customized to approach the exact angle of the ACL or PCL. It should be noted that the angles B and D may be exaggerated in the drawings. The length and diameter of each column 152 may be different from the length and diameter shown and can be customized to approach the length and diameter of the ACL or PCL. Each column 152 may not necessarily extend straight along the longitudinal axis as shown, but may be curved instead to approach the curved shape of the ACL or PCL.

[0053] Each post 152 includes a convex rounded surface that rotatably and slidably engages with a concave surface of a contoured portion 156 of a recess 157. Note that the post 152 and contoured portion 156 are in sliding contact but are physically separated from each other. Although not shown, the recess 157 may be formed in a separate insert (such as the box 11) that is removably attached to the femoral component 158.

[0054] Fig.11 An alternative embodiment of a knee prosthesis 160 is depicted, which is similar to the knee prosthesis 150, except that posts 159a and 159b are disposed on a femoral component 162 and engage contours 161a and 161b, respectively, disposed on a recess 163 formed on an articular insert 165 of the tibial portion (or the tibial portion itself). The positions of the posts and contours are interchangeable, however, it is noted that the positions and geometries of the posts 159a and 159b continue to mimic the positions and geometries of the ACL and PCL, respectively. Likewise, as in Fig. 9 1. In the embodiment shown in FIG. 1, and although not shown, each of the articular insert 165 and the femoral component 162 may include an angled post and a contoured portion.

[0055] Fig.12 An alternative embodiment of a knee prosthesis 180 is depicted. The knee prosthesis 180 is similar to the knee prosthesis 150, and the major differences will be described below. In the knee prosthesis 180, a post 182 that mimics the PCL is disposed on a tibial portion 184 and engages with a contoured recess 186 on a femoral portion 188. An artificial ligament 190 that mimics the ACL is secured to the tibial portion 184 and the femoral portion 188. Fig.12 Fixed values ​​are indicated by small 'xxx' characters.

[0056] The post 182 extends from the posterior lateral side of the joint insert 184 to the anterior medial side of the femoral component 188 to mimic the location of the PCL. The ligament 190 extends from the anterior medial side of the joint insert 184 to the posterior lateral side of the femoral component 188 to mimic the location of the ACL. Unlike the post 182, the ligament 190 is fixedly connected to both the joint insert 184 and the femoral component 188. The post 182 and ligament 190 are oriented in a cruciate shape as seen in the sagittal plane and the frontal plane, however, the post 182 and ligament 190 may be oriented in a cruciate shape as seen in only one of those planes.

[0057] Fig.13 An alternative embodiment of a knee prosthesis 192 is depicted that is similar to prosthesis 180 except that the positions of ligament 190' and post 182' are swapped such that ligament 190' represents the PCL and post 182' represents the ACL. Fig.12 and Fig.13Alternatively, if the patient's native ACL or PCL is retained in the partial knee replacement, post 182 may be omitted entirely.

[0058] The ligaments shown herein are formed of artificial materials (preferably synthetic fibers or cables) to replace the ACL or PCL, such that the artificial materials are configured to be similar to the corresponding orientation and position of the ACL and PCL in a normal knee. Specifically, the configuration is such that the origin and insertion points of the artificial materials in the TKR are similar to the origin and insertion points of the ACL and PCL in a normal knee.

[0059] Fig.14 Describes an alternative embodiment of a knee prosthesis 200, which is similar to the knee prosthesis 150, except that the free end of the PCL column 202 includes a spiral protrusion 204, which can be a mechanical thread. The contoured portion 206 in the femoral component that receives the spiral protrusion 204 includes a spiral recess 208. The spiral recess 208 interacts with the spiral protrusion 204 to cause a slight rotation around the axis Y when the knee prosthesis 200 moves between the extended position and the flexed position. The slight rotation simulates the slight rotation experienced in the real knee joint when it is fully extended. The spiral surfaces 204 and 208 can alternatively be provided in the form of wedge-shaped, angled or sloped surfaces.

[0060] It should be understood that the term "artificial" only means that it is not the original anatomical ACL or PCL ligament in its original form prior to TKR, and should not be construed as limited to the use of only synthetic materials. Thus, the artificial ligament may include "natural" materials (such as materials composed of biologically produced materials), and / or may include a mixture of synthetic and natural materials. Other exemplary materials may include variations of braided polyethylene, which is similar to the material previously sold as SecureStrand® cable, braided ultra-high molecular weight polyethylene (UHMWPE) cable for surgical fixation in posterior spine reconstruction, currently sold as Super Cables® (Kinamed, Camarillo, California) made of UHMWPE and nylon 6 / 6,6, Gore-tex® (PTFE fiber manufactured by WL Gore and Associates, Newark, Delaware), carbon fiber, or other similar braided materials.

[0061] According to various embodiments of the present invention, artificial materials in the form of, for example, artificial ligaments may be incorporated into the TKR at the time of surgery, or the TKR may be preassembled with the artificial materials prior to surgery. Various methods and devices for connecting ligaments to tibial and femoral components are described in U.S. Patent Application Publication No. 2017 / 0252173 to Garino. As described in that reference, the locking mechanism for the ends of the artificial ligament is not limited to any particular configuration and may include, for example, a spherical retainer, a metal clamp, a hook, a ring, a fastener in the form of a nail.

[0062] Reviewing the embodiments described above, it should be appreciated that posts, contours and ligaments may be positioned on different components and in different locations, or may be connected to different components and in different locations. Therefore, the embodiments described above should not be viewed as limiting.

[0063] Fig.15A and 15B Depicted is a side view of an alternative embodiment of a knee prosthesis 300 as seen in the sagittal plane, wherein a tibial component 302 is coupled to a femoral component 304 via a rack and pinion type gear assembly. It should be appreciated that Fig.15A and 15B The portion of the knee prosthesis 300 shown in FIG. 1 does not represent the entire knee prosthesis. Rather, Fig.15A and 15B The portion of the knee prosthesis 300 shown in FIG. 1 represents the portion of the tibial portion 302 and the femoral portion 304 that contact each other within the area of ​​a box (such as box 11). Fig.15A is shown in the extended position and in Fig. 15B The teeth 306 on the tibial portion 302 mesh with the teeth 308 of the femoral portion 304 so that rotation of the tibial portion 302 causes rotation of the femoral portion 304, and vice versa.

[0064] Figures 16A-16C An alternative embodiment of a knee prosthesis 400 is depicted in which a tibial portion 402 is coupled to a femoral portion 404 via a gear drive assembly. The knee prosthesis 400 is substantially similar to the knee prosthesis 300, and the major differences between those embodiments will be described below.

[0065] The tibial portion 402 includes a rounded and convex outer surface on which teeth 406 are disposed. The convex outer surface includes a rear segment 406a having a simple curved path following the arc of a circle and a front segment 406b following a spiral path. The spiral path extends inwardly as seen in the forward direction. The teeth also follow the trajectory of the spiral path of the front portion 406b. The rear segment 406a intersects the front segment 406b in a progressive manner.

[0066] Similarly, the femoral portion 404 includes a raised outer surface on which teeth 408 are disposed. The raised outer surface includes a rear segment 408a having a simple curved path following the arc of a circle and an anterior segment 408b following a spiral path. The spiral path extends inwardly as seen in the forward direction. It should be understood that the teeth also follow the trajectory of the spiral path of the anterior segment 408b. The rear segment 408a intersects the anterior segment 408b in a progressive manner.

[0067] Although both the posterior segment 408a and the anterior segment 408b are shown and described as following a helical trajectory, only one of those segments may follow a helical trajectory.

[0068] The teeth 406 on the tibial portion 402 mesh with the teeth 408 of the femoral portion 404 so that the rotation of the tibial portion 402 causes the rotation of the femoral portion 404, and vice versa. Similarly, when the tibial portion 402 rotates to the extended position in the forward direction, the tibial portion 402 also moves in the inward direction. The slight rotation of the tibial portion 402 in the inward direction simulates the slight rotation experienced therein when the real knee joint is fully extended. The rotation in the inward direction is due to the spiral geometry of the front portion 406b and 408b of the matching.

[0069] Fig.17 An alternative embodiment of a knee prosthesis 500 is depicted as viewed in the sagittal plane, wherein the tibial portion is coupled to the femoral portion by an assembly of a post 502 and a contour 504. The knee prosthesis 500 is substantially similar to the knee prosthesis 300, except that the teeth 306 and 308 are replaced by a post 502 and a contour 504, respectively. It should be understood that the teeth 406 and 408 of the knee prosthesis 300 may similarly be replaced by an assembly of a post and a contour, such as the assembly of a post and a contour of the knee prosthesis 500.

[0070] As in Fig.18 As shown in FIG. 5 , the placement of posts 506 and contours 508 may be interchanged without departing from the scope or spirit of the present invention.

[0071] Fig.19 6 is a plan view depicting an alternative embodiment of a knee prosthesis 600 in which the tibial component T is coupled to the femoral component F by an assembly of a pin 602 and a slot 604. Fig.19 In the embodiment, the knee prosthesis 600 is shown in a flexed position. Fig.19 The portion of the knee prosthesis 600 shown in illustrative figures represents only the portions of the tibial portion T and the femoral portion F that are in contact with each other in the area of ​​a box (eg, box 11).

[0072] According to this embodiment, the pin 602 is disposed on the femoral portion F and the slot 604 is disposed on the tibial component T, however, the reverse may also be true. The pin 602 extends in a vertical direction into the depth of the slot 604. In operation, the pin 602 travels along the length of the slot 604. As seen in the forward direction, the slot 604 curves in an inward direction.

[0073] In operation, when the tibial portion T rotates in the anterior direction to the extended position and the pin 602 travels along the length of the slot 604, the tibial portion T also rotates in the medial direction. The slight rotation of the tibial portion T in the medial direction simulates the slight rotation experienced in a real knee joint when it is fully extended. The movement in the medial direction is due to the curvature of the slot 604.

[0074] The components of knee joint prosthesis can be made of the same or similar materials. However, generally, all materials are preferably inert, not prone to infection, and are safe and approved for use as surgical implants in addition. Exemplary materials include polyethylene, metal alloys approved in surgery, ceramic materials approved in surgery or their combinations. Any known material in the field of surgical implants can be used to make any embodiment or its part according to the various embodiments of the present invention.

[0075] Although preferred embodiments of the present invention have been shown and described herein, it will be understood that such embodiments are provided only as examples. Those skilled in the art may conceive of many variations, changes and substitutions without departing from the spirit of the present invention. Therefore, it is intended that the appended claims cover all such variations 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 knee prosthesis comprising: a femoral component configured to be mounted to a femur; a tibial component configured to be mounted to the tibia and to engage the femoral component to form the knee prosthesis; a first post fixedly connected to one of the femoral component and the tibial component and a first contoured recess defined on the other of the femoral component and the tibial component, the first contoured recess configured to engage the first post in the extended position or the flexed position of the knee prosthesis; as well as a second post fixedly connected to one of the femoral component and the tibial component and a second contoured recess defined on the other of the femoral component and the tibial component, the second contoured recess configured to engage the second post in the extended position or the flexed position of the knee prosthesis, Wherein, the first column, the second column, the first contoured recess and the second contoured recess are each positioned between adjacent condyles of the knee prosthesis.

2. The knee joint prosthesis according to claim 1, characterized in that: The first post is fixedly connected to the femoral component, and the second post is fixedly connected to the femoral component.

3. The knee joint prosthesis according to claim 1, characterized in that: The first post is fixedly connected to the tibial component, and the second post is fixedly connected to the tibial component.

4. The knee joint prosthesis according to claim 1, characterized in that: The first post is fixedly connected to the tibial component, and the second post is fixedly connected to the femoral component.

5. The knee joint prosthesis according to claim 1, characterized in that: The first post is fixedly connected to the femoral component, and the second post is fixedly connected to the tibial component.

6. The knee joint prosthesis according to claim 1, characterized in that: The tibial component includes an articular insert.

7. The knee joint prosthesis according to claim 1, characterized in that: Each post includes a rounded convex surface and each contoured recess is a rounded concave surface.

8. The knee joint prosthesis according to claim 1, characterized in that: Each post is slidingly engaged with but separate from a corresponding contoured recess.

9. The knee joint prosthesis according to claim 1, characterized in that: The post or the contoured recess forms part of a removable insert configured to be connected to the femoral component or the tibial component.

10. The knee joint prosthesis according to claim 1, characterized in that: The first and second posts are oriented in a cruciform as seen in the sagittal plane, the frontal plane, or both the sagittal and frontal planes.

11. The knee joint prosthesis according to claim 1, characterized in that: The femoral component and the tibial component contact each other at a load-bearing surface, and the post extends in a direction directed away from the load-bearing surface.

12. The knee joint prosthesis according to claim 1, characterized in that: At least one of the posts and one of the contoured recesses include a helical surface to induce rotation of the knee prosthesis as the knee prosthesis moves between the flexed position and the extended position.

13. A knee prosthesis configured to move between an extended position and a flexed position, the knee prosthesis comprising: a femoral component configured to be mounted to a femur; a tibial component configured to be mounted to a tibia, the tibial component configured to engage the femoral component to form the knee prosthesis; a post fixedly connected to one of the femoral component and the tibial component and a contoured recess defined on the other of the femoral component and the tibial component, the contoured recess configured to engage the post in the extended position or the flexed position of the knee prosthesis; as well as an artificial ligament fixedly connected to the femoral component and the tibial component to simulate the anterior cruciate ligament or the posterior cruciate ligament, Therein, the columns and the ligaments are oriented in a cruciate shape as seen in the sagittal plane, the frontal plane, or both the sagittal plane and the frontal plane.

14. The knee joint prosthesis according to claim 13, characterized in that: The post is fixedly connected to the femoral component, and the contoured recess is defined in the tibial component.

15. The knee joint prosthesis according to claim 13, characterized in that: The post is fixedly connected to the tibial component, and the contoured recess is defined in the femoral component.

16. The knee joint prosthesis according to claim 13, characterized in that: In both the sagittal plane and the frontal plane, the columns and ligaments are oriented cruciately.

17. The knee joint prosthesis according to claim 13, characterized in that: The tibial component includes an articular insert.

18. The knee joint prosthesis according to claim 13, characterized in that: Each post includes a rounded convex surface and each contoured recess is a rounded concave surface.

19. The knee joint prosthesis according to claim 13, characterized in that: The post is slidingly engaged with but separate from the contoured recess.

20. The knee joint prosthesis according to claim 13, characterized in that: The post, the contoured recess, or the ligament forms part of a removable insert configured to be connected to the femoral component or the tibial component.

21. A knee prosthesis configured to move between an extended position and a flexed position, the knee prosthesis comprising: a femoral component configured to be mounted to a femur; as well as a tibial component configured to be mounted to a tibia, the tibial component configured to engage the femoral component to form the knee prosthesis; wherein the femoral component and the tibial component are at least partially connected together via a gear transmission assembly, wherein the gears of the tibial component mesh with the gears of the femoral component, and wherein at least one of the gears follows a helical trajectory to cause movement of the tibial component in a medial direction when the knee prosthesis is moved to the extended position.

Images