Artificial knee joint, beam member for use in the artificial knee joint, insertion member, and base plate

Abstract

An artificial knee joint (1) has: an insertion member (2) which is embedded in a part of an articular surface of a medial condyle (MC) or a lateral condyle (LC) of a tibia (T); and a beam member (3) which is disposed below the insertion member (2) and has a length in which both ends are fixed to a cortical bone of the tibia (T).

Description

Technical Field

[0001] The present invention relates to an artificial knee joint, a beam component, an insertion component, and a base plate used in the artificial knee joint. Background Technology

[0002] The knee joint is formed by the femur, tibia, and patella. Within the knee joint, the articular cartilages at the distal end of the femur and the proximal end of the tibia, along with the meniscus located between them, act as a buffer, allowing the knee joint to function smoothly.

[0003] However, if the knee cartilage wears down due to obesity, aging, or other factors, leading to meniscus damage, not only will the cushioning between the distal femur and proximal tibia be lost, but knee joint deformities will also occur, and these deformities will progress over time. Additionally, knee joint deformities can also occur in cases of rheumatoid arthritis or knee injuries. In cases of the aforementioned knee joint deformities (deformed knee joint syndrome), the knee joint cannot function smoothly, causing extreme pain when walking and making walking difficult.

[0004] As a treatment for this type of deforming knee joint syndrome, total knee arthroplasty (TKA) is performed. TKA involves removing the distal femur and proximal tibia and replacing the removed portions with an artificial knee joint. Even now, most patients undergo TKA, as it relieves pain and allows for normal walking, resulting in high patient satisfaction. Furthermore, many artificial knee joints designed for use in TKA have been developed (see Patent Documents 1 and 2).

[0005] In addition, in recent years, unicompartmental knee arthroplasty (UKA), which involves replacing only a portion of the knee joint with an artificial knee joint, has also been adopted. Patent document 3 below discloses a partial unicompartmental system for unicompartmental knee arthroplasty.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-172992

[0007] Patent Document 2: Japanese Patent Application Publication No. 2001-120583

[0008] Patent Document 3: Japanese Patent Publication No. 2018-502651

[0009] However, in existing total knee arthroplasty and unicompartmental knee arthroplasty, the meniscus cannot be preserved in principle. Furthermore, in total knee arthroplasty, the entire articular surface is removed and replaced with an artificial knee joint, making it difficult to reproduce the original articular surface height. This change in the original articular surface height leads to numerous reports of unexpected postoperative pain and limited range of motion, thus limiting patient satisfaction. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide an artificial knee joint that can obtain characteristics close to those of a normal knee joint, a beam component, an insertion component, and a base plate for use in the artificial knee joint.

[0011] The artificial knee joint of the present invention comprises: an insertion member embedded in a portion of the articular surface of the medial or lateral condyle of the tibia; and

[0012] A beam component, which is disposed below the aforementioned insertion component, and has a length at both ends fixed to the cortical bone of the aforementioned tibia.

[0013] According to this structure, the insert is embedded only in a portion of the articular surface, thereby ensuring that the surface of the insert aligns with the surrounding remaining articular surface, thus reproducing the original articular surface height. Furthermore, by reproducing the original articular surface height, the meniscus can also be preserved. As a result, the artificial knee joint according to the present invention achieves characteristics close to those of a normal knee joint. Attached Figure Description

[0014] Figure 1 It is a three-dimensional diagram showing the usage status of an artificial knee joint.

[0015] Figure 2 It is a perspective view and a sectional view showing the inserted component.

[0016] Figure 3 It is a three-dimensional diagram representing the beam component.

[0017] Figure 4A This is a three-dimensional view of the base plate.

[0018] Figure 4B These are perspective views and cross-sectional views showing the usage state of the base plate involved in other embodiments.

[0019] Figure 4C These are top and side views of the base plate involved in other embodiments.

[0020] Figure 4D This is a 3D view of the fins.

[0021] Figure 4E This is a top view of the base plate involved in other embodiments.

[0022] Figure 4F This is a top view of the base plate involved in other embodiments.

[0023] Figure 4G This is a top view of the base plate involved in other embodiments.

[0024] Figure 4H This is a top view of the base plate involved in other embodiments.

[0025] Figure 4I This is a top view of the base plate involved in other embodiments.

[0026] Figure 4J This is a side view of the base plate involved in other embodiments.

[0027] Figure 4K These are top and side views of the base plate involved in other embodiments.

[0028] Figure 4L These are top and side views of the base plate involved in other embodiments.

[0029] Figure 5 It is a three-dimensional diagram and a top view showing the surgical steps.

[0030] Figure 6A These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0031] Figure 6B These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0032] Figure 6C These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0033] Figure 6D These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0034] Figure 6E These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0035] Figure 6F These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0036] Figure 6G These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0037] Figure 6H These are top and front views showing the usage state of the artificial knee joint involved in other embodiments.

[0038] Figure 7 These are top and side views of the insertion component involved in other embodiments. Detailed Implementation

[0039] Hereinafter, with reference to the accompanying drawings, an artificial knee joint according to one embodiment of the present invention will be described. The artificial knee joint of the present invention is used in total knee replacement surgery for the treatment of osteoarthritis of the knee, rheumatoid arthritis, etc., and is characterized by forming a structure that preserves the meniscus and ligaments.

[0040] Artificial knee joint

[0041] Figure 1 This indicates the usage status of artificial knee joint 1. Figure 2 Figure 4 shows the components of the artificial knee joint 1. In the following description of the artificial knee joint 1, the direction of the extension of the tibia T is referred to as the superior-inferior direction, and the anterior-posterior and lateral directions of the patient in the tibia T are referred to as the anterior-posterior direction and the lateral direction, respectively.

[0042] The artificial knee joint 1 includes an insertion member 2 embedded in a portion of the articular surface of the medial condyle (MC) or lateral condyle (LC) of the tibia (T), and a beam member 3 disposed below the insertion member 2. Additionally, the artificial knee joint 1 may also include a base plate 4 disposed between the insertion member 2 and the beam member 3. Figure 1 In this case, the insert 2 is embedded in a portion of the articular surface of the lateral condyle LC.

[0043] Insertion component 2 is implanted by removing a portion of the articular surface of the medial condyle (MC) or lateral condyle (LC) of the tibia. Insertion component 2 is implanted by adjusting its height and surface shape so that its surface smoothly connects with the surrounding original articular surface.

[0044] Multiple types of insert components 2 are preferably prepared. Figure 2 Insertion parts 2a to 2c with different shapes are shown. Figure 2 The perspective view and sectional view of the inserted parts 2a to 2c are shown.

[0045] Insertion components 2a-2c are generally disc-shaped. Insertion component 2a is embedded in the medial condyle MC of the tibial T1, forming a concave curved surface. Insertion component 2b is embedded in the lateral condyle LC of the tibial T1, forming a convex curved surface. In addition, the surface of insertion component 2c is formed as a flat surface.

[0046] Concentric steps 20 are formed on the lower surface of the insertion parts 2a to 2c for fitting the upper end of the cylindrical base plate 4. Alternatively, if the base plate 4 is not provided, the steps 20 are not formed.

[0047] The diameter of the insertion parts 2a to 2c is, for example, 15 to 25 mm, preferably 17 to 22 mm. In practice, multiple insertion parts 2a to 2c with different diameters are prepared in advance, so that the most suitable size of insertion part 2a to 2c can be selected while referring to the patient's MRI images, etc.

[0048] The thickness of the insertion components 2a to 2c is, for example, 4 mm or more. Multiple insertion components 2a to 2c of different thicknesses are prepared in advance, so that the most suitable thickness of the insertion component 2a to 2c is selected while referring to images such as the patient's MRI. This allows the surface height of the insertion components 2a to 2c to match the original joint surface height.

[0049] Furthermore, the recess of the insertion member 2a embedded in the medial condyle MC is, for example, 1 to 2 mm, and the bulge of the insertion member 2b embedded in the lateral condyle LC is, for example, 1 to 2 mm. The surfaces of the insertion members 2a to 2c are formed to smoothly connect with the original articular surfaces surrounding the embedded portion.

[0050] The insertion parts 2a to 2c are made of materials with high sliding properties and wear resistance (e.g., high molecular weight polyethylene).

[0051] The beam member 3 is positioned horizontally below the insertion member 2 to support the insertion member 2 from below. The beam member 3, which forms this raft function, is also referred to as a raft pin. Furthermore, the beam member 3 does not necessarily need to contact the lower surface of the insertion member 2. That is, the beam member 3 may also not contact the lower surface of the insertion member 2, but instead support the insertion member 2 via the cancellous bone within the tibial T.

[0052] The shape of beam component 3 is not particularly limited. Figure 3 Beam components 3a to 3c with different shapes are shown. Figure 3 This shows a three-dimensional view of beam components 3a to 3c.

[0053] Beam components 3a-3c are rod-shaped components, having two ends fixed to the cortical bone of the tibia T along their long sides. Thus, beam components 3a-3c become end-fixation beams, with both ends fixed to rigid cortical bone. The length of beam components 3a-3c is, for example, 30-80 mm. In practice, multiple beam components 3a-3c of different lengths are prepared in advance, and during surgery, the depth of the holes into which the beam components 3a-3c are inserted is measured using a depth gauge to select the most suitable length. Beam components 3a-3c are prepared, for example, at a spacing of 2 mm, preferably 1 mm. Furthermore, the width of beam components 3a-3c is, for example, 2-8 mm.

[0054] The cross-sectional shape of beam component 3 is not particularly limited. The cross-section of beam component 3a is circular. However, the cross-section of beam component 3a can also be elliptical.

[0055] The cross-section of beam component 3b is triangular. Beam component 3b can be used as follows: Figure 3 The triangle is configured so that its vertices face upwards, but it can also be configured so that its base faces upwards, forming an inverted triangular cross-section. Positioning the beam member 3b with its base facing upwards enhances the functionality of the support insertion member 2.

[0056] The cross-section of beam component 3c is quadrilateral. Here, quadrilateral is excluding... Figure 3 In addition to the rectangle shown, it also includes the concepts of square, trapezoid, rhombus, etc.

[0057] The shape of beam member 3a with a circular cross-section is simpler, but considering strength, beam member 3b with a triangular cross-section and beam member 3c with a quadrilateral cross-section are preferred. Alternatively, beam member 3b and beam member 3c can be driven into a circular through hole opened by a drill bit or the like.

[0058] Beam components 3a to 3c are made of biocompatible and rigid materials (e.g., titanium, stainless steel, etc.).

[0059] A base plate 4 is disposed between the insertion member 2 and the beam member 3. The base plate 4 is cylindrical and fits into the step 20 formed on the lower surface of the insertion member 2, supporting the outer edge of the insertion member 2 from below. The wall thickness of the cylindrical base plate 4 is, for example, 1 mm.

[0060] For the base plate 4, multiple base plates 4 of different heights can be prepared. Therefore, when adjusting the height of the insertion component 2, adjustment can be made via the base plate 4 without using the insertion component 2 itself. Alternatively, a height adjustment plate (not shown) can be separately disposed between the base plate 4 and the beam component 3.

[0061] The base plate 4 does not need to contact the beam component 3. That is, the base plate 4 may not contact the beam component 3, but the cancellous bone of the tibia T is sandwiched between the two.

[0062] The shape of the base plate 4 is not particularly limited. Figure 4A The base plates 4a to 4d with different shapes are shown. Figure 4A This shows a three-dimensional view of the base plate 4a to 4d. Figure 4B It is a perspective view and sectional view showing the 4D usage state of the base plate.

[0063] The base plate 4a has fitting holes 41 and fitting grooves 42 formed in the cylindrical portion 40 for fitting two beam members 3c with quadrilateral cross sections. The two beam members 3c are arranged in a cross shape. By combining the base plate 4a and the beam members 3c, the base plate 4a and the beam members 3c become one, thus improving the function of supporting the insertion member 2.

[0064] The base plate 4b is a bottomed cylinder with a cylindrical portion 40 and a bottom portion 43. This structure prevents the insertion member 2 from sinking when a large load is applied.

[0065] The base plate 4c has a mesh-like opening at the lower part of the cylindrical portion 40, forming a grid-like mesh portion 44. With this structure, the mesh portion 44 prevents the base plate 4c from sinking and maintains the cylindrical shape by reinforcing the cylindrical portion 40. Furthermore, the mesh portion 44 increases the installation area, thereby improving the support function for the plaster-cement-installed base plate 4c.

[0066] The base plate 4d is configured such that the upper end face of the cylindrical portion 40 is inclined relative to a surface orthogonal to the cylindrical axis. On the other hand, the lower end face of the cylindrical portion 40 is parallel to the surface orthogonal to the cylindrical axis. That is, the upper end face of the base plate 4d is formed inclined relative to the lower end face. The base plate 4d and... Figure 4B The insertion member 2d shown is used in combination. The upper surface of the insertion member 2d is also formed as an inclined plane relative to the cylindrical axis of the base plate 4d, similar to the upper end surface of the base plate 4d. Furthermore, the step 20 of the insertion member 2d is parallel to the upper surface. According to this structure, by rotating the base plate 4d about the cylindrical axis, the height of the insertion member 2d can be adjusted in a manner consistent with the height and shape of the articular surface of the actual tibia T. At this time, protrusions and grooves that engage with these protrusions can also be provided on the contact surfaces of the step 20 of the insertion member 2d and the upper end surface of the base plate 4d without rotating the insertion member 2d relative to the base plate 4d. The shape and number of protrusions are not particularly limited; for example, they can be at least one point-like protrusion, or multiple linear protrusions extending radially about the cylindrical axis.

[0067] Figures 4C to 4LThis refers to the base plate 4 in other embodiments. The base plate 4 may also have a cylindrical portion 40 (an example of a cylindrical portion) and a protrusion that protrudes outward from the outer peripheral surface of the cylindrical portion 40. By providing the protrusion on the outer peripheral surface of the cylindrical portion 40, it is possible to suppress the sinking of the base plate 4.

[0068] Figure 4C These are the top and side views of the base plate 4e. Figure 4D This is a perspective view of fin 45. A base plate 4e has fins 45 on a cylindrical portion 40. Four fins 45 are arranged circumferentially on the cylindrical portion 40. Fins 45 are plate-shaped components formed from the same material as the cylindrical portion 40. Fins 45 have rectangular portions 45a and triangular portions 45b. A portion of the triangular portion 45b protrudes outward from the outer periphery of the cylindrical portion 40. The triangular portion 45b has a sharp tip that allows it to easily penetrate the cancellous bone.

[0069] The cylindrical portion 40 has an opening 40a that connects the inside of the cylinder to the outside. The width of the opening 40a is slightly wider than the width of the rectangular portion 45a of the fin 45. Therefore, the fin 45 can protrude from the inside of the cylinder to the outside through the opening 40a. Additionally, the fin 45 may also have a stop 45c that limits the amount of protrusion from the outer peripheral surface of the cylindrical portion 40. The stop 45c restricts the movement of the fin 45 by contacting the inner peripheral surface of the cylindrical portion 40.

[0070] In addition, such as Figure 4E As shown, the shapes of each fin 45 can also be different, thereby changing the amount of protrusion of the triangular portion 45b from the outer peripheral surface of the cylindrical portion 40. For example, the amount of protrusion of the triangular portion 45b can be reduced in places near the cortical bone and increased in places far from the cortical bone.

[0071] Figure 4F This is a top view of the base plate 4f. The base plate 4f has four fins 46 on its cylindrical portion 40. Each fin 46 has a rectangular portion 46a and a semi-circular portion 46b. A portion of the semi-circular portion 46b protrudes from the outer peripheral surface of the cylindrical portion 40.

[0072] Figure 4G This is a top view of the base plate 4g. The base plate 4g has eight fins 45 in the cylindrical portion 40. Furthermore, the number of fins 45 is not particularly limited, but it is preferable to have three or more.

[0073] Figure 4H This is a top view of the base plate 4h. The base plate 4h has four fins 47 on its cylindrical portion 40. The fins 47 extend in a circumferentially inclined direction relative to the normal direction of the outer peripheral surface of the cylindrical portion 40.

[0074] Figure 4IThis is a top view of the base plate 4i. The fins 47 of the base plate 4i are aligned with... Figure 4H The base plate shown extends in different directions.

[0075] Figure 4J This is a side view of the base plate 4j. The base plate 4j has fins 48 extending obliquely downward from the outer peripheral surface of the cylindrical portion 40.

[0076] Figure 4K The base plate 4k shown has threads 49 provided on the outer circumferential surface of the cylindrical portion 40. The threads 49 are intermittently arranged circumferentially along the outer circumferential surface of the cylindrical portion 40. Furthermore, multiple rows of threads 49 are arranged in the vertical direction. Although the threads 49 are intermittently arranged circumferentially along the outer circumferential surface of the cylindrical portion 40, they may also be arranged throughout the entire circumference of the outer circumferential surface of the cylindrical portion 40. Preferably, the lower surface of the threads 49 is inclined upwards towards the anterior end in a manner that facilitates insertion of the base plate 4k into the tibia (see enlarged view).

[0077] Figure 4L The base plate 4m shown has recesses 50 on the outer circumferential surface of the cylindrical portion 40. The recesses 50 are intermittently arranged circumferentially along the outer circumferential surface of the cylindrical portion 40. Furthermore, multiple rows of recesses 50 are arranged in the vertical direction. Over time, cancellous bone will infiltrate the recesses 50, thereby inhibiting the sinking of the base plate 4m. In addition, although the recesses 50 are intermittently arranged circumferentially along the outer circumferential surface of the cylindrical portion 40, they can also be arranged throughout the entire circumference of the outer circumferential surface of the cylindrical portion 40.

[0078] also, Figures 4C to 4L The cylindrical portion 40 shown is a cylindrical shape with openings at the top and bottom, but it can also be provided with... Figure 4A Alternatively, as shown in (b), the bottom 43 can be configured as follows: Figure 4A The mesh portion 44 is as shown in (c).

[0079] [Surgical Procedure]

[0080] Figure 5 An example representing a surgical procedure. Figure 5 (a) shows the articular surface wear of the lateral condyle LC of the tibia T. First, a through hole extending in the anterior-posterior direction is formed below the articular surface of the lateral condyle LC using a drill or the like. Two through holes are formed, arranged in the lateral direction. Next, as shown... Figure 5 As shown in (b), the beam component 3 is driven into the through hole. Next, a circular hole with a diameter corresponding to the diameter of the inserted component 2 is formed on the outer condyle LC above the beam component 3. Next, as... Figure 5 As shown in (c), the base plate 4 is inserted into the circular hole formed above the beam component 3. Finally, as... Figure 5As shown in (d), the insertion part 2 is fitted into the upper end of the base plate 4.

[0081] As described above, the artificial knee joint 1 of this embodiment includes: an insertion member 2, which is embedded in a portion of the articular surface of the medial condyle MC or the lateral condyle LC of the tibia T; and a beam member 3, which is disposed below the insertion member 2 and has a length that is fixed at both ends to the cortical bone of the tibia T.

[0082] According to the artificial knee joint 1 of this embodiment, the insertion member 2 is embedded only in a portion of the articular surface. This allows the surface of the insertion member 2 to match the height and shape of the remaining articular surface around it, thus reproducing the original height of the articular surface. Furthermore, by reproducing the original height of the articular surface, the meniscus can also be preserved.

[0083] Furthermore, in the artificial knee joint 1 of this embodiment, only a portion of the joint is replaced, thus the surgery is easier, less invasive, and the risk of bleeding is reduced. The anterior cruciate ligament (ACL) can be preserved, and reconstruction can be performed simultaneously even when ACL injury is observed. In addition, all ligaments except the meniscus can be preserved, particularly the previously more difficult deep medial collateral ligament (dMCL).

[0084] The insert component 2 can also contact the beam component 3. According to this structure, the insert component 2 is reliably supported from below by the beam component 3.

[0085] The insert component 2 may not contact the beam component 3. This structure allows for a certain degree of gap between the insert component 2 and the beam component 3, thus suppressing damage under large loads.

[0086] The outer edge portion of the insert 2 that adjoins the meniscus is preferably formed in an arc shape. This structure prevents interference with the meniscus while preserving it.

[0087] Beam component 3 can also be configured only along the front-to-back direction. If beam component 3 is configured along the left-to-right direction, there is a concern that when a large load is applied to one of the inner condyles MC or the outer condyles LC, it may have an adverse effect on the other condyle MC or the outer condyle LC via beam component 3.

[0088] The artificial knee joint 1 of this embodiment may also include a cylindrical base plate 4, which is disposed between the insertion member 2 and the beam member 3, and supports the outer edge of the insertion member 2. According to this structure, the insertion member 2 is reliably supported from below by the base plate 4 and the beam member 3.

[0089] The base plate 4 can also contact the beam member 3. According to this structure, the base plate 4 is reliably supported from below by the beam member 3.

[0090] The base plate 4 may not be in contact with the beam component 3. With this structure, a certain gap can be provided between the base plate 4 and the beam component 3, so that the base plate 4 can be lowered and the height of the insertion component 2 can be adjusted appropriately.

[0091] The upper part of the base plate 4 may also have an inclined surface that is inclined relative to a surface orthogonal to the cylindrical axis. According to this structure, by rotating the base plate 4 about the cylindrical axis, the height of the insertion member 2 can be adjusted in a manner consistent with the height and shape of the articular surface of the actual tibia T.

[0092] The surface of the insertion member 2a embedded in the medial condyle MC of the tibia T is preferably formed as a concave curved surface. Normally, the original articular surface of the medial condyle MC becomes a concave curved surface, so according to this structure, the surface of the insertion member 2a is smoothly connected to the surrounding original articular surface.

[0093] The surface of the insert 2b, which is implanted in the lateral condyle LC of the tibia T, is preferably formed as a convex curved surface. Normally, the original articular surface of the lateral condyle LC becomes a convex curved surface, so according to this structure, the surface of the insert 2b is smoothly connected to the surrounding original articular surface.

[0094] Furthermore, the artificial knee joint 1 is not limited to the structure of the above-described embodiments, nor is it limited to the effects described above. In addition, the artificial knee joint 1 can of course be modified in various ways without departing from the spirit of the invention. For example, the structures and methods of the various embodiments described above can be combined arbitrarily. Furthermore, one or more of the structures and methods described in the various modifications below can be arbitrarily selected and applied to the structures and methods described in the above-described embodiments.

[0095] For example, Figure 6A This is an example of embedding the insertion component 2 in a portion of the articular surface of the medial condyle MC and the lateral condyle LC. The base plate 4 is not shown in this figure, but it can be provided, as is the case in the following figures.

[0096] Figure 6B This is an example of how insert part 2 forms a D-shape when viewed from above. Figure 6C This is an example of how insert part 2 forms a semi-circle when viewed from above. Figure 6D This is an example of how insert part 2 forms an ellipse when viewed from above.

[0097] Figure 6E This is an example where a beam member 3 extending in the front-to-back direction is also provided, along with a beam member 3 extending in the left-to-right direction.

[0098] Figure 6FThis is an example of a beam member 3 that extends in the front-to-back direction and a beam member 3 that extends in the left-to-right direction, which are arranged relative to each insertion member 2. Figure 6G This is an example of a beam member 3 that extends in the front-to-back direction and two beam members 3 that extend in the left-to-right direction, relative to each insertion member 2. Figure 6H This is an example of a component 3 consisting of only three beams extending in the left-right direction.

[0099] Figure 7 These are top and side views of the insertion member 2e according to other embodiments. The insertion member 2e is supported from below by the beam member 3 without passing through the base plate 4. Therefore, the insertion member 2e is disc-shaped without forming the step 20. The disc-shaped insertion member 2e has protrusions 21 on its outer peripheral surface. The protrusions 21 are intermittently arranged along the outer peripheral surface of the insertion member 2e in the circumferential direction. In addition, the protrusions 21 are arranged in multiple rows in the vertical direction. The protrusions 21 are preferably inclined upwards towards the front end in a manner that facilitates insertion of the insertion member 2e into the tibia (see enlarged view).

[0100] In addition, if a unicompartmental knee arthroplasty (UKA) is performed on the medial condyle (MC), it is also possible to use an artificial knee joint only on the lateral condyle (LC) 1.

[0101] Explanation of reference numerals in the attached figures

[0102] 1…Artificial knee joint; 2…Insertion component; 2a…Insertion component; 2b…Insertion component; 2c…Insertion component; 2d…Insertion component; 3…Beam component; 3a…Beam component; 3b…Beam component; 3c…Beam component; 4…Base plate; 4a…Base plate; 4b…Base plate; 4c…Base plate; 4d…Base plate; 4e…Base plate; 4f…Base plate; 4g…Base plate; 4h…Base plate; 4i…Base plate; 4j…Base plate; 4k…Base plate; 4m…Base plate; 40…Cylindrical part; 40a…Opening part; 43…Bottom; 44…Mesh part; 45…Fin; 46…Fin; 47…Fin; 48…Fin; 49…Linear part; 50…Recess; T…Tibia; MC…Medial condyle; LC…Lateral condyle.

Claims

1. An artificial knee joint, characterized in that, have: An insert is embedded in a portion of the articular surface of the medial or lateral condyle of the tibia, and its height and shape are adjusted in such a way that its surface smoothly connects with the surrounding original articular surface. A beam member, disposed below the insertion member, and having a length at both ends fixed to the cortical bone of the tibia, the beam member supporting the insertion member from below; and A cylindrical base plate is disposed between the insertion member and the beam member, providing support for the outer edge of the insertion member. The beam components are arranged along the front-to-back and left-to-right directions. The base plate has a mesh-like opening at the bottom of the cylindrical section.

2. The artificial knee joint according to claim 1, characterized in that, The insertion component does not contact the beam component.

3. The artificial knee joint according to claim 1, characterized in that, The beam components are configured only along the front-to-back direction.

4. The artificial knee joint according to claim 1, characterized in that, The base plate is in contact with the beam component.

5. The artificial knee joint according to claim 1, characterized in that, The base plate does not contact the beam component.

6. The artificial knee joint according to claim 1, characterized in that, The upper part of the base plate has an inclined surface that is inclined relative to a surface orthogonal to the cylindrical axis.

7. The artificial knee joint according to claim 1, characterized in that, The surface of the insert component is formed as a concave curved surface, a convex curved surface, or a flat surface.

8. The artificial knee joint according to claim 1, characterized in that, The insertion component is circular, elliptical, or semi-circular when viewed from above.

Images