Artificial knee replacement for cruciate ligament injury

Abstract

To provide prostheses that replicate the function provided by both ACL and PCL, in order to provide a more anatomically correct TKR.SOLUTION: A knee joint prosthesis is capable of moving between an extended position and a flexion position. The knee joint prosthesis includes a femoral component that is configured to be mounted to a femur, a tibial component that is configured to be mounted to a tibia, a post fixedly connected to one of the femoral component and the tibial component, and a cam recess defined on the other of the femoral component and the tibial component that is configured to be engaged by the post in either the extended position or the flexion position of the knee joint prosthesis. The knee joint prosthesis may also include an artificial ligament that extends between the femoral component and the tibial component. The post and the ligament mimic one of the ACL and PCL.SELECTED DRAWING: Figure 7A

Description

【Technical Field】 【0001】 The present invention relates to an artificial knee prosthesis used for total knee arthroplasty (TKR), and more particularly to a knee joint prosthesis having an artificial anterior cruciate ligament (ACL) and / or a posterior cruciate ligament (PCL). 【Background Art】 【0002】 As described in Patent Document 1 for Garino (US Patent Application Publication No. 2017 / 0252173), which is incorporated herein by reference in its entirety, for all applications, artificial knees generally include three main components: a femoral component (FIGS. 1A and 1B) attached to the distal end of the femur, a tibial component (FIGS. 2A and 2B) implanted on the proximal end of the tibia, and an articular insert (FIGS. 3A and 3B) assembled on the tibial component to provide a friction surface for the femoral component. The components are designed to simulate the associated mechanics of the human knee throughout the joint and the entire range of knee motion. The components are generally provided in a variety of shapes with varying dimensions (identified as dimensions A-H and J-T in FIGS. 1A-3B), thus enabling the physician to select the optimal combination of components according to the patient's specific anatomy. The size and shape of the knee are influenced by various factors including the patient's age, gender, and size. Therefore, a fairly wide range of component inventories are generally available to enable adjustment of the artificial knee to the patient. 【0003】 During normal knee construction in the case of TKR, the ACL is removed in most cases, and depending on the selected TKR design, the patient's PCL is either retained or replaced by some mechanism to substitute for the lost function of the PCL. Even when the PCL is retained, in many cases, a portion of the PCL must be cut or partially cut during surgery to assist in balancing the knee replacement. When the PCL is completely removed, the PCL is substituted by a post and cam mechanism. 【0004】 The TKR generally includes a femoral component 10, a tibial component 16, and an articular insert 22 that resides on the upper mounting portion 20 of the tibial component 16 for interacting with the femoral component 10. Referring to Figures 1A, 1B, 3A, and 3B, an example of a typical design of the post and cam mechanism is provided. The articular insert 22 includes an extension 24 that protrudes into the opening 12 of the femoral component 10. A box 11 with upwardly projecting walls is formed on the interior side of the femoral component 10 and includes an internal region that intersects with the opening 12. The extension 24 includes a posterior surface 25 intended to be in frictional contact with the posterior surface 14 of the opening 12 when the joint is flexed. The resistance generated when the extension 24 is bearing in contact with the posterior surface 14 of the opening 12 within the femoral component 10 is intended to simulate the resistance that would be generated by a healthy posterior cruciate ligament (PCL). 【0005】 Cam and post mechanisms have been manufactured that partially replace the function of the ACL by creating a cam surface between the front surface of the extension portion 24 and the front surface of the opening 12. However, this solution only provides a partial replacement for the ACL because the front side of the extension portion 24 can only contact the front side of the opening when it is bent at most 0 to 20 degrees. 【0006】 Another solution involves connecting the femoral and tibial components with cable-like materials, such as those disclosed in Patent Document 2 (U.S. Patent No. 5,935,133), the content of which is incorporated herein by reference. However, these artificial materials are typically used only to replace the PCL and not the ACL. 【0007】 Due to the lack of anatomically appropriate replacement, TKR reconstructions may result in less functional knees compared to the original knee. This can cause difficulties during postoperative physical therapy and limit the patient's ability or desire to participate in physical activity after therapy. Almost all modern total knee replacements sacrifice the ACL or improperly replace the knee joint with immature cam and post mechanisms, leaving the reconstructed knee with only similar motor function to that of a knee with ACL insufficiency. Therefore, the motor function of a normal knee remains difficult to grasp. Furthermore, due to the lack of proper interaction between the ACL and PCL (both of which drive the kinematics of a normal knee), TKR reconstructions remain below the point where they can produce a knee that is relatively normal for the patient. 【0008】 Due to the complexity of knee joint mechanics and the difficulty patients face in adapting to artificial knees after surgery, there is a need for anatomically appropriate knee replacement systems that more accurately simulate the restorative force and support previously provided by the removed ligaments. To provide a more anatomically appropriate total knee replacement (TKR), an embodiment of the prosthesis that replicates the functions provided by both the ACL and PCL is desired. 【0009】 Referring to Figure 4, a healthy human knee is illustrated with loop 30, representing an exemplary artificial ACL / PCL ligament, drawn over the original anatomical ACL and PCL locations. The divisions constituting the artificial PCL in loop 30 are demarcated by points 26A and 26B. The divisions constituting the artificial ACL in loop 30 are demarcated by points 28A and 28B. 【0010】 Herein, according to Figures 5, 6A and 6B illustrating embodiments disclosed in Patent Document 1 to Garino, the connection points 26a, 26b, 28a and 28b of the artificial material provided as ligament 44 and the length spanning between the connection points provided as the contour of the artificial ligament 44 are configured to simulate the dimensions and attachment points of the ACL and PCL in the human knee as illustrated in Figure 4. At least one artificial ligament of a certain length can be provided to connect the femoral component 10 and the joint insert 22 of the TKR. 【0011】 While Patent Document 1 for Garino provides a solution to these complexities, there is a constant need for further development in this field to improve the mechanics of the knee joint. [Prior art documents] [Patent Documents] 【0012】 [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0252173 [Patent Document 2] U.S. Patent No. 5,935,133 [Overview of the Initiative] 【0013】 According to one embodiment of the present invention, a knee joint prosthesis has the ability to move between an extended position and a flexed position. The knee joint prosthesis includes a femoral component configured to be attached to the femur, and a tibial component configured to be attached to the tibia, which is configured to engage with the femoral component to form a knee joint prosthesis. A first post is fixedly connected to one of the femoral component and the tibial component, and a first cam recess is defined on the other of the femoral component and the tibial component, configured to engage with the first post in either the extended or flexed position of the knee joint prosthesis. A second post is fixedly connected to one of the femoral component and the tibial component, and a second cam recess is defined on the other of the femoral component and the tibial component, configured to engage with the second post in either the extended or flexed position of the knee joint prosthesis. 【0014】 In another embodiment of the present invention, the knee joint prosthesis includes a femoral component configured to be attached to the femur, and a tibial component configured to be attached to the tibia, which is configured to engage with the femoral component to form the knee joint prosthesis. A post is fixedly connected to one of the femoral and tibial components, and a cam recess is defined on the other of the femoral and tibial components and is configured to engage with the first post in either the extended or flexed position of the knee joint prosthesis. An artificial ligament is fixedly connected to the femoral and tibial components to simulate either the anterior cruciate ligament or the posterior cruciate ligament. The post and ligament are oriented to intersect when viewed in the sagittal plane, the frontal plane, or both the sagittal and frontal planes. 【0015】 In yet another embodiment of the present invention, the knee joint prosthesis includes a femoral component configured to be attached to the femur and a tibial component configured to be attached to the tibia. The tibial component is configured to engage with the femoral component to form the knee joint prosthesis. The femoral component and the tibial component are connected together, at least partially, by a geared arrangement. [Brief explanation of the drawing] 【0016】 The drawing is as follows: [Figure 1A] This is a side view of a femoral component for a knee joint prosthesis, known to those skilled in the art. [Figure 1B] Figure 1A is a bottom view of the femoral bone components. [Figure 2A] This is a top view of a tibial component for a knee joint prosthesis known to those skilled in the art. [Figure 2B] Figure 2A is a side view of the tibia components. [Figure 3A] This is a top view of a joint implant for a knee joint prosthesis, known to those skilled in the art. [Figure 3B] This is a front view of the joint insert shown in Figure 3B, which is assembled on the base plate of the tibial component. [Figure 4] This is a lateral view of the knee joint illustrating the anatomical locations of the ACL and PCL and the composition of artificial materials intended to replace the ACL and PCL. [Figure 5] This is a side view of femoral components, joint implants, and artificial ligaments for TKR related to prior art. [Figure 6A] Figure 5 is a top view of the cross-section along line II. [Figure 6B] This is a bottom view of the cross-section along line II in Figure 5. [Figure 7A] This is a sagittal plane cross-sectional side elevation view of a knee joint prosthesis, according to an exemplary embodiment of the present invention, in which the knee joint prosthesis is shown in the extended position. [Figure 7B]Another view of the knee joint prosthesis of FIG. 7A, shown in the flexed position. [Figure 8] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with a post disposed on the femoral portion and a cam disposed on the tibial portion. [Figure 9] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with one post and one cam disposed on each of the femoral and tibial portions. [Figure 10A] Depicts a partial cross-sectional view of an embodiment of the knee joint prosthesis as seen in the sagittal plane, with posts mimicking the ACL and PCL disposed on the tibial portion and engaging a cam on the femoral portion. [Figure 10B] Depicts the knee joint prosthesis of FIG. 10A as seen from the frontal plane. [Figure 11] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with posts mimicking the ACL and PCL disposed on the femoral portion and engaging a cam on the tibial portion. [Figure 12] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with a post mimicking the PCL disposed on the tibial portion and engaging a cam on the femoral portion, and an artificial ligament mimicking the ACL disposed between the tibial and femoral portions. [Figure 13] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with a post mimicking the ACL disposed on the tibial portion and engaging a cam on the femoral portion, and an artificial ligament mimicking the PCL disposed between the tibial and femoral portions. [Figure 14] Depicts a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with posts mimicking the ACL and PCL disposed on the femoral portion and engaging a cam on the femoral portion. [Figure 15A] Depicts a side elevation view of a modified embodiment of the knee joint prosthesis as seen in the sagittal plane, with the tibial portion coupled to the femoral portion by a toothed arrangement. The knee joint prosthesis is shown in the extended position. [Figure 15B]This diagram shows a lateral elevation view of a modified knee joint prosthesis in the sagittal plane, where the tibia portion is connected to the femur portion by a gear-like arrangement. The knee joint prosthesis is shown in a flexed position. [Figure 16A] This diagram shows a lateral elevation view of a modified knee joint prosthesis in the sagittal plane, in which the tibia portion is connected to the femur portion by a gear-equipped arrangement, and the gear-equipped arrangement is configured to cause medial movement of the tibia portion to the extended position at the time of rotation. [Figure 16B] The knee joint is shown from the posterior side. [Figure 16C] The knee joint is shown from the front. [Figure 17] This illustration depicts a modified form of a knee joint prosthesis viewed in the sagittal plane, where the tibia portion is connected to the femur portion by a post and cam arrangement. [Figure 18] This illustration depicts a modified form of a knee joint prosthesis viewed in the sagittal plane, where the tibia portion is connected to the femur portion by a post and cam arrangement. [Figure 19] This is a plan view illustrating a modified embodiment of a knee joint prosthesis, in which the tibia portion is connected to the femur portion by pin and slot arrangement. [Modes for carrying out the invention] 【0017】 The present invention provides various embodiments of a knee joint 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, the joint insert represents the lateral side or direction, "F" represents the femoral component, and "T" represents the tibial component (or a joint insert that forms part of the tibial component). 【0018】 Figure 7A is a sagittal cross-sectional side elevation view of a knee joint prosthesis 100, in an exemplary embodiment of the present invention, showing the knee joint prosthesis 100 in an extended position. Figure 7B is another view of the knee joint prosthesis 100 of Figure 7A, showing the knee joint prosthesis 100 in a flexed position. The knee joint prosthesis 100 has the ability to rotate between the extended position in Figure 7A and the flexed position in Figure 7B. 【0019】 The prosthesis 100 generally includes an articular insert 104 that is attached to or forms part of the femoral component 102 and the tibia component. 【0020】 The femoral component 102 shown in Figures 7A and 7B may represent a femoral component having condyloid processes (such as item 10) or a box assembled to a femoral component (such as box 11). A recess 108 is formed at the lower end of the femoral component 102. The recess 108 is located between the condyloid processes 106 along the medial-lateral direction. Where the recess 108 intersects with the outer surface of the femoral component 102, a margin 111 is formed at the semicircular boundary of the recess 108. The recess 108 is located in the same approximate location as the opening 12 within the femoral component 10. However, unlike the opening 12, the recess 108 is blind and contains a smooth, rounded inner surface. Two cam surfaces 110a and 110b (referred to individually or collectively as cam surfaces 110) are formed at the opposing ends of the inner surface of the recess 108. Each cam 110 is a smooth, rounded concave surface. The radii of the cam 110 may be the same or different. The cam 110 is configured to interact with rounded posts 112a and 112b that extend from the upper surface of the joint insert 104. 【0021】 The joint insert 104 is similar to the joint insert 22, and the main differences between these inserts are described below. The joint insert 104 includes two posts 112a and 112b (referred to individually or collectively as post surfaces 112) extending from the support surface 113. Post 112a corresponds to the ACL, while post 112b corresponds to the PCL. Each rounded post 112 terminates with a convexly rounded surface. The radius of each post 112 may be the same as or substantially the same as the radius of each cam 110. The height and radius of the extended portion of the post 112 may be different (as shown) or the same to complement the geometry of the meshing cam 110. In this embodiment, the ACL post 112a has a greater height than the PCL post 112b. The posts 112 extend along their respective axes Z perpendicular to the support surface 113. Alternatively, post 112 may extend obliquely in relation to axis Z. Post 112 in Figure 7A and all other posts described herein may be integral with the articular insert 22 (or other components to which the post is connected) as illustrated, or connected to the articular insert 22 by mechanical threads, bolts, friction, adhesive, cement, or any other means known to those skilled in the art for assembling two components together. 【0022】 The joint implant 104 has the ability to rotate in relation to the femoral component 102 between the extended position in Figure 7A and the flexed position in Figure 7B. In the extended position of the knee joint prosthesis 100, the condyloid process may rest on the supporting surface 113 of the joint implant 104, and the posts 112 are positioned in contact with their respective cams 110. As the femoral component 102 rotates relative to or from the joint implant 104, the posts 112 advance along the surface of the cams 110 until the edge 111 of the recess 108 is supported on the base of the posterior post 112. The ACL post 112a may be supported on its cam 110a. Although not shown, collateral ligaments (MCL and LCL) adjacent to the knee joint prosthesis 100 prevent the femoral component 102 from dislocating from the joint implant 104. 【0023】 By arranging two posts 112 and two cams 110, the arrangement of the PCL and ACL is more closely mimicked compared to conventional knee joint prostheses with a single post and a single cam. 【0024】 As described above, the recess 108 may be formed in a separate insert that can be attached to the femoral component 102, similar to the box 11. A series of inserts with different recess geometric shapes may be provided as a kit, so that a medical professional can select an insert with the geometric shape that best fits the patient's specific biomimetic structure. 【0025】 Figure 8 depicts a knee joint prosthesis 118 in which posts 122a and 122b are positioned on a femoral component 124 and a cam 128 is defined in a recess 130 positioned on a joint insert 132 of a tibial component. The knee joint prosthesis 118 is similar to the knee joint prosthesis 100, except that the positions of the posts and cam are swapped. The operation of the knee joint prosthesis 118 is substantially similar to that of the knee joint prosthesis 100. Although not shown, posts 122a and 122b may be formed in separate inserts that can be attached to the femoral component 124, similar to the box 11. 【0026】 Figure 9 illustrates knee joint prosthesis 136. Knee joint prosthesis 136 is similar to knee joint prosthesis 100, except that one post 138 and one cam recess 140 are positioned on the femoral component 142, and one post 144 and one cam recess 146 are positioned on the articular insertion 148 of the tibial component. In the extended position shown in Figure 9, post 138 of femoral component 142 is assembled with cam recess 146 of tibial articular insertion 148, and post 144 of tibial articular insertion 148 is assembled with cam recess 140 of femoral component 142. Post 138 is positioned anterior to recess 140, but it should be understood that the positions of post 138 and recess 140 (along with the positions of recess 146 and post 144) are interchangeable. The movement of knee joint prosthesis 136 is substantially similar to the movement of knee joint prosthesis 100. 【0027】 Figures 10A and 10B depict one embodiment of a partial cross-sectional view of the knee joint prosthesis 150. The prosthesis 150 is similar to the prosthesis 100, and only the main differences between them will be described. In the knee joint prosthesis 150, posts 152a and 152b (collectively referred to as posts 152), which more closely mimic the PCL and ACL respectively, are positioned on the tibial portion of the articular insert 154 (or the tibial portion itself) and engage with cams 156a and 156b (collectively referred to as cams 156), which are positioned on a recess 157 formed on the femoral component 158. The recess 157 extends upward from the supporting surface 155 of the prosthesis 150. 【0028】 Specifically, the post 152a, extending from the lateral and posterior sides of the articular insert 154 to the medial and anterior sides of the femoral component 158, more closely mimics the location and geometry of the PCL. The post 152b, extending from the medial and anterior sides of the articular insert 154 to the lateral and posterior sides of the femoral component 158, more closely mimics the location and geometry of the ACL. Although the posts 152a and 152b are oriented to intersect when viewed in the sagittal plane and in the frontal plane, they can also be oriented to intersect only when viewed in one of these planes. 【0029】 The angle "B" of each post 152 in relation to the supporting surface 155 when viewed in the sagittal plane may vary from that shown and may be adjusted to approximate the exact angle of the ACL or PCL. Similarly, the angle "D" of each post 152 in relation to the supporting surface 155 of the articular insert 154 when viewed in the frontal plane may vary from that shown and may be adjusted to approximate the exact angle of the ACL or PCL. It should be noted that angles B and D may be exaggerated in the figure. The length and diameter of each post 152 may vary from those shown and may be adjusted to approximate those of the ACL or PCL. Each post 152 does not necessarily have to extend straight along the longitudinal axis as shown, but may instead be curved to approximate the curved shape of the ACL or PCL. 【0030】 Each post 152 includes a convex, rounded surface that rotatably and slidably engages with the concave surface of the cam 156 in the recess 157. It should be noted that the posts 152 and the cam 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 a box 11, which is removablely attached to the femoral component 158. 【0031】 Figure 11 depicts a modified embodiment of knee joint prosthesis 160, which is similar to knee joint prosthesis 150 except that posts 159a and 159b are positioned on the femoral component 162 and engage with cams 161a and 161b, respectively, which are positioned on a recess 163 formed on the tibial portion articular insertion 165 (or the tibial portion itself). It is noted that while the locations of the posts and cams are interchangeable, the locations and geometry of posts 159a and 159b continue to mimic those of the ACL and PCL, respectively. Similarly, as in the embodiment shown in Figure 9, although not illustrated, each of the articular insertion 165 and femoral component 162 may include one angled post and one cam. 【0032】 Figure 12 illustrates a modified embodiment of the knee joint prosthesis 180. The knee joint prosthesis 180 is similar to the knee joint prosthesis 150, and the main differences are described below. In the knee joint prosthesis 180, a post 182 mimicking the PCL is positioned on the tibial portion 184 and engages with a cam recess 186 on the femoral portion 188. An artificial ligament 190 mimicking the ACL is fixed to the tibial portion 184 and the femoral portion 188. The fixation is indicated by lowercase "xxx" in Figure 12. 【0033】 Post 182 extends from the lateral and posterior sides of the articular insertion 184 to the medial and anterior sides of the femoral component 188, mimicking the location of the PCL. Ligament 190 extends from the medial and anterior sides of the articular insertion 184 to the lateral and posterior sides of the femoral component 188, mimicking the location of the ACL. Unlike post 182, ligament 190 is fixedly connected to both articular insertion 184 and femoral component 188. Post 182 and ligament 190 are oriented to intersect when viewed in the sagittal and frontal planes, although they may also be oriented to intersect only when viewed in one of these planes. 【0034】 Figure 13 depicts a modified embodiment of knee joint prosthesis 192, which is similar to prosthesis 180 except that the locations of ligament 190' and post 182' are swapped, so that ligament 190' represents the PCL and post 182' represents the ACL. Alternatively, post 182 can be completely removed if the patient's natural ACL or PCL is preserved in partial knee replacement. 【0035】 The ligaments described herein are formed from artificial materials, preferably synthetic fibers or twisted yarns, for the purpose of replacing the ACL or PCL, and are therefore constructed in a manner similar to the orientation and location of the ACL and PCL in a normal knee. Specifically, the construction is such that the origin and insertion points of the artificial material within the TKR are similar to the origin and insertion points of the ACL and PCL in a normal knee. 【0036】 Figure 14 depicts a modified embodiment of a knee joint prosthesis 200, which is similar to the knee joint prosthesis 150 except that the free end of the PCL post 202 includes a helical projection 204, which may be a mechanical thread. The cam 206 within the femoral component that accommodates the helical projection 204 includes a helical recess 208. The helical recess 208 interacts with the helical projection 204 to cause a slight rotation about axis Y as the knee joint prosthesis 200 moves between the extended and flexed positions. This slight rotation mimics the slight rotation felt in an actual knee joint when fully extended. The helical surfaces 204 and 208 may, alternatively, be provided in the form of wedge-shaped, angled, or tapered surfaces. 【0037】 The term “artificial” simply means that it is not the original anatomical ACL or PCL ligament in its original form prior to TKR, and should not be interpreted as a limitation to the use of synthetic materials only. Therefore, artificial ligaments may include “natural” materials, such as materials made from biologically created materials, and / or hybrids of synthetic and natural materials. Other exemplary materials may include a variant of woven polyethylene similar to the material previously marketed as Secure Strand® cable, a braided ultra-high molecular weight polyethylene (UHMWPE) cable used for surgical fixation in posterior spinal cord reconstruction; the material currently marketed as Super Cables® (Kinamed, Inc., Camarillo, CA) made from UHMWPE and Nylon 6 / 6.6; Gore-tex® (PTFE fiber manufactured by WLGore and Associates, Inc., Newark, DE); carbon fiber; or other similar woven materials. 【0038】 According to various embodiments of the present invention, for example, an artificial material in the form of an artificial ligament can be incorporated into the TKR at the time of surgery, or the TKR can be pre-assembled with the artificial material prior to surgery. Various methods and devices for connecting the ligament to tibial and femoral components are described in U.S. Patent Application Publication No. 2017 / 0252173 to Garino. As described in this reference, the locking mechanism for the end of the artificial ligament is not limited to any particular configuration and may include spherical retainers, metal clips, hooks, loops, claw-shaped fasteners, and the like. 【0039】 In consideration of the embodiments described above, it should be recognized that the post, cam, and ligament can be connected to different components at different locations. Therefore, the embodiments described above should not be considered limiting. 【0040】 Figures 15A and 15B depict side elevation views of a modified embodiment of the knee joint prosthesis 300 as viewed in the sagittal plane, in which the tibial portion 302 is connected to the femoral portion 304 by a rack-and-pinion type geared arrangement. It should be understood that the portions of the knee joint prosthesis 300 shown in Figures 15A and 15B do not represent the entire knee joint prosthesis. Rather, the portions of the knee joint prosthesis 300 shown in Figures 15A and 15B represent the portions of the tibial portion 302 and the femoral portion 304 that come into contact with each other within the box (such as box 11). The knee joint prosthesis 300 is shown in the extended position in Figure 15A and in the flexed position in Figure 15B. The teeth 306 on the tibia portion 302 occlude with the teeth 308 on the femoral portion 304, so that rotation of the tibia portion 302 causes rotation of the femoral portion 304, and vice versa. 【0041】 Figures 16A-16C depict a modified embodiment of the knee joint prosthesis 400 in which the tibial portion 402 is connected to the femoral portion 404 by a gear-equipped arrangement. The knee joint prosthesis 400 is substantially similar to the knee joint prosthesis 300, and the main differences between these embodiments are described below. 【0042】 The tibial portion 402 includes a rounded, convex outer surface on which teeth 406 are positioned. The convex outer surface includes a posterior segment 406a having a simple curved path following an arc and an anterior segment 406b following a helical path. The helical path extends medially when viewed in the anterior direction. The teeth similarly follow the trajectory of the helical path of the anterior segment 406b. The posterior segment 406a intersects the anterior segment 406b in a stepped manner. 【0043】 Similarly, the femoral portion 404 includes a convex outer surface on which teeth 408 are positioned. The convex outer surface includes a posterior segment 408a having a simple curved path following an arc and an anterior segment 408b following a helical path. The helical path extends inward when viewed in the anterior direction. It should be understood that the teeth similarly follow the trajectory of the helical path of the anterior segment 408b. The posterior segment 408a intersects the anterior segment 406b in a stepwise manner. 【0044】 Although both the rear segment 408a and the front segment 408b are illustrated and described as following a helical trajectory, it is also possible for only one of these segments to follow a helical trajectory. 【0045】 The teeth 406 on the tibial portion 402 occlude with the teeth 408 on the femoral portion 404, so that rotation of the tibial portion 402 causes rotation of the femoral portion 404, and vice versa. Similarly, as the tibial portion 402 rotates anteriorly to the extension position, the tibial portion 402 also moves medially. This slight medial rotation of the tibial portion 402 mimics the slight rotation felt within the actual knee joint when fully extended. This medial rotation is due to the helical geometry of the interlocking anterior portions 406b and 408b. 【0046】 Figure 17 illustrates a modified embodiment of the knee joint prosthesis 500 as viewed in the sagittal plane, where the tibial portion is connected to the femoral portion by the arrangement of the post 502 and cam 504. The knee joint prosthesis 500 is substantially similar to the knee joint prosthesis 300, except that the teeth 306 and 308 are replaced by the post 502 and cam 504, respectively. It should be understood that the teeth 406 and 408 of the knee joint prosthesis 300 can be similarly replaced by a post-cam arrangement, such as the post-cam arrangement of the knee joint prosthesis 500. 【0047】 As shown in Figure 18, the arrangement of post 506 and cam 508 can be changed without departing from the scope or spirit of the invention. 【0048】 Figure 19 is a plan view illustrating a modified embodiment of a knee joint prosthesis 600 in which the tibial portion T is connected to the femoral portion F by the arrangement of pins 602 and slots 604. The knee joint prosthesis 600 is shown in the flexed position in Figure 19. As with other embodiments, the portion of the knee joint prosthesis 600 shown in Figure 19 represents only the portions of the tibial portion T and the femoral portion F that are in contact with each other within the area of ​​a box (such as box 11), and not the entire knee joint prosthesis. 【0049】 In this embodiment, the pin 602 is positioned on the femoral portion F and the slot 604 is positioned on the tibial component T, although the reverse may also be true. The pin 602 extends perpendicularly into the depth of the slot 604. During operation, the pin 602 moves along the length of the slot 604. The slot 604 curves medially when viewed in the anterior direction. 【0050】 During movement, tibial segment T rotates anteriorly to an extended position, and as pin 602 advances along the length of slot 604, tibial segment T also rotates medially. This slight medial rotation of tibial segment T mimics the slight rotation felt within an actual knee joint when fully extended. The medial movement is due to the curvature of slot 604. 【0051】 The components of a knee joint prosthesis may be manufactured from the same or similar materials. However, generally speaking, all materials are preferably inert, not prone to infection, and otherwise safe, as they are approved for use as surgical grafts. Exemplary materials include polyethylene, surgically approved metal alloys, surgically approved ceramic materials, or combinations thereof. Any of the various embodiments or parts thereof of the present invention can be manufactured using any well-known material in the field of surgical grafts. 【0052】 While preferred embodiments of the present invention have been illustrated and described herein, it should be understood that such embodiments are provided only as examples. Those skilled in the art will be able to conceive of many variations, modifications, and substitutions without departing from the spirit of the invention. Therefore, the appended claims are intended to cover all such variations that fall within the spirit and scope of the invention. This disclosure also includes the following aspects: [Aspect 1] In a knee joint prosthesis configured to move between an extended position and a flexed position, Femoral components configured to be attached to the femur; A tibial component that is attached to the tibia and configured to engage with the femoral component to form the knee joint prosthesis; A first post fixedly connected to one of the femoral and tibial components, and a first cam recess defined on the other of the femoral and tibial components and configured to engage with the first post in either the extension or flexion position of the knee joint prosthesis; A second post fixedly connected to one of the femoral and tibial components, and a second cam recess defined on the other of the femoral and tibial components and configured to engage with the second post in either the extension or flexion position of the knee joint prosthesis; Knee joint prostheses including knee joint implants. [Aspect 2] The knee joint prosthesis according to embodiment 1, wherein the first post is fixedly connected to the femoral component, and the second post is fixedly connected to the femoral component. [Aspect 3] The knee joint prosthesis according to embodiment 1, wherein the first post is fixedly connected to the tibial component, and the second post is fixedly connected to the tibial component. [Aspect 4] The knee joint prosthesis according to embodiment 1, wherein the first post is fixedly connected to the tibial component and the second post is fixedly connected to the femoral component. [Aspect 5] The knee joint prosthesis according to embodiment 1, wherein the first post is fixedly connected to the femoral component and the second post is fixedly connected to the tibia component. [Aspect 6] The knee joint prosthesis according to embodiment 1, wherein the tibial component includes a joint insert. [Aspect 7] A knee joint prosthesis according to embodiment 1, wherein each post includes a rounded convex surface and each cam recess has a rounded concave surface. [Aspect 8] The knee joint prosthesis according to embodiment 1, wherein each post is engaged in a sliding manner with its respective cam recess and is further disengaged from the cam recess. [Aspect 9] The knee joint prosthesis according to embodiment 1, wherein either the post or the cam recess forms part of a removable insert configured to connect to either the femoral component or the tibia component. [Aspect 10] The knee joint prosthesis according to embodiment 1, wherein the first post and the second post are oriented to intersect when viewed in the sagittal plane, the frontal plane, or both the sagittal plane and the frontal plane. [Aspect 11] The knee joint prosthesis according to embodiment 1, wherein the femoral component and the tibia component are in contact with each other on the support surface, and the post extends in a direction away from the support surface. [Aspect 12] The knee joint prosthesis according to embodiment 1, wherein at least one of the posts and one of the cams include a helical surface such that it causes rotation of the knee joint prosthesis as the knee joint prosthesis moves between a flexion position and an extension position. [Aspect 13] In a knee joint prosthesis configured to move between an extended position and a flexed position, Femoral components configured to be attached to the femur; A tibial component configured to be attached to the tibia, the tibial component configured to engage with the femoral component to form the knee joint prosthesis; A post fixedly connected to one of the femoral and tibia components, and a cam recess defined on the other of the femoral and tibia components, configured to engage with the post in either the extension or flexion position of the knee joint prosthesis; An artificial ligament fixedly connected to the femoral and tibial components, simulating either the anterior cruciate ligament or the posterior cruciate ligament; Includes, The post and the ligament are oriented to intersect when viewed in the sagittal plane, the frontal plane, or both the sagittal and frontal planes. Knee joint prosthesis. [Aspect 14] The knee joint prosthesis according to embodiment 13, wherein the post is fixedly connected to the femoral component and the cam recess is defined within the tibial component. [Aspect 15] The knee joint prosthesis according to embodiment 13, wherein the post is fixedly connected to the tibial component and the cam recess is defined within the femoral component. [Aspect 16] The knee joint prosthesis according to embodiment 13, wherein the post and the ligament are oriented to intersect in both the sagittal plane and the frontal plane. [Aspect 17] The knee joint prosthesis according to embodiment 13, wherein the tibial component includes a joint insert. [Aspect 18] A knee joint prosthesis according to embodiment 13, wherein each post includes a rounded convex surface and each cam recess has a rounded concave surface. [Aspect 19] The knee joint prosthesis according to embodiment 13, wherein the post is engaged with a cam recess in a sliding manner and is further disengaged from the cam recess. [Aspect 20] The knee joint prosthesis according to embodiment 13, wherein the post, the cam recess, or the ligament constitutes part of a removable insert configured to be connected to either the femoral component or the tibia component. [Aspect 21] In a knee joint prosthesis configured to move between an extended position and a flexed position, Femoral components configured to be attached to the femur; A tibial component configured to be attached to the tibia, the tibial component configured to engage with the femoral component to form the knee joint prosthesis; Includes, A knee joint prosthesis in which the femoral component and the tibia component are connected together at least partially by a geared arrangement. [Aspect 22] The knee joint prosthesis according to embodiment 21, wherein the gears of the tibial component mesh with the gears of the femoral component, and at least one of the gears follows a helical trajectory, causing medial movement of the tibial component as the knee joint prosthesis is moved to the extended position. [Explanation of symbols] 【0053】 10 Femoral components 12 Openings 16 Tibial components 20 Upper assembly part 22 Joint implants 24 Extension 25 Rear surface 30 loops 44, 190 ligaments 100, 118, 150, 192, 200, 3000, 400, 500 Knee joint prostheses 102, 124, 142, 150, 158, 162, 188 Femoral components 104, 132, 148, 154 Joint implants 106 Condylar process 108, 130, 140, 146, 157, 163 depressions 110, 128, 156, 504, 508 Cam 111 Edge Posts 112, 122, 138, 144, 152, 182, 502, 506 113, 155 Supporting surface

Claims

[Claim 1] In a knee joint prosthesis configured to move between an extended position and a flexed position, Femoral components configured to be attached to the femur; A tibial component configured to be attached to the tibia, the tibial component configured to engage with the femoral component to form the knee joint prosthesis; Includes, The femoral component and the tibia component are connected together at least partially by a geared arrangement, the geared arrangement includes a femoral gear positioned on the femoral component and a tibia gear positioned on the tibia component, the femoral gear and the tibia gear mesh with each other, For each of the aforementioned femoral gear and tibial gear, the rear toothed segment of each gear has a simple curved path following an arc, and the front toothed segment of each gear follows a helical path. The posterior toothed segment of each of the femoral gear and the tibial gear includes a plurality of interconnected gear teeth, each of which teeth of the interconnected gear teeth extends (i) along a horizontal plane passing through the knee joint prosthesis, and (ii) perpendicular to a vertical plane passing through the knee joint prosthesis. Each of the front toothed segments of the femoral gear and the tibial gear includes a plurality of interconnected gear teeth, and each tooth of the interconnected gear teeth of the front toothed segment extends along a plane oblique to both the horizontal and vertical planes. Knee joint prosthesis. [Claim 2] The knee joint prosthesis according to claim 1, wherein the femoral gear and the tibial gear mesh in both the extension and flexion positions. [Claim 3] The knee joint prosthesis according to claim 1, wherein both the femoral gear and the tibial gear are at least partially cylindrical. [Claim 4] The knee joint prosthesis according to claim 1, wherein the femoral gear is non-rotatably mounted to the femoral component, and the tibial gear is non-rotatably mounted to the tibial component. [Claim 5] The knee joint prosthesis according to claim 1, wherein the femoral gear is inclined with respect to the plane of the femoral component, and the tibial gear is inclined with respect to the plane of the tibial component. [Claim 6] The knee joint prosthesis according to claim 1, wherein the femoral gear and the tibial gear are each positioned between adjacent condyloid processes of the knee joint prosthesis. [Claim 7] In a knee joint prosthesis configured to move between an extended position and a flexed position, Femoral components configured to be attached to the femur; A tibial component configured to be attached to the tibia, the tibial component configured to engage with the femoral component to form the knee joint prosthesis; Includes, The femoral component and the tibia component are connected together at least partially by a geared arrangement, A knee joint prosthesis in which the gears of the tibial component mesh with the gears of the femoral component, and at least one of the gears follows a helical trajectory, causing medial movement of the tibial component as the knee joint prosthesis is moved to the extended position.

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