Cushion for artificial knee joint and method for constructing rear fork bed of cushion for artificial knee joint

Abstract

The application discloses a spacer for artificial knee joint and a method for constructing a posterior femoral condyle of the spacer for artificial knee joint. The spacer for artificial knee joint comprises a body which is fixed to an upper resection surface of a tibia. The body comprises an inner support part and an outer support part which are oppositely arranged in a width direction of the body. The inner support part and the outer support part respectively bear an inner condyle and an outer condyle of a femur. A posterior surface of the body is a posterior condyle surface. The posterior condyle surface is formed with a recessed part which is open to the back and is used for avoiding a posterior cruciate ligament of a human body. The recessed part is located between the inner support part and the outer support part. A surface of the recessed part is recessed inward to form a posterior femoral condyle. The surface of the posterior femoral condyle extends upward in a direction away from the posterior condyle surface so that a space above the posterior femoral condyle is adapted to a movement space of the posterior cruciate ligament of the human body. The spacer for artificial knee joint can completely avoid the posterior cruciate ligament, thereby avoiding the posterior cruciate ligament from being cut and damaged.

Description

Technical Field

[0001] This invention relates to the field of medical prosthesis technology, specifically to a liner for an artificial knee joint and a method for constructing a rear fork bed for the liner for an artificial knee joint. Background Technology

[0002] Currently, total knee replacement surgery is mainly divided into posterior cruciate ligament (PCL) preservation and PCL replacement. PCL preservation allows for the preservation of more bone mass compared to PCL replacement, and it also provides greater stability during activity.

[0003] In related technologies, the padding of prostheses that preserve the posterior cruciate ligament only avoids the insertion point of the posterior cruciate ligament, without avoiding the entire posterior cruciate ligament. This results in the ligament being cut at the edge of the padding ligament avoidance area, which can easily damage the posterior cruciate ligament or cause discomfort to the patient during exercise. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention provide a liner for an artificial knee joint. The liner includes a body having a medial support portion for supporting the medial condyle and a lateral support portion for supporting the lateral condyle. The posterior condylar surface of the body has a posteriorly opening recessed portion located between the medial and lateral support portions to avoid the posterior cruciate ligament (PCL). The surface of the recessed portion is concave inward to form a posterior cruciate bed. The surface of the posterior cruciate bed extends upward in a direction away from the posterior condylar surface. Thus, by forming the posterior cruciate bed inward based on the recessed portion, and the orientation of the inclined posterior cruciate bed surface is consistent with the PCL, a space capable of accommodating the PCL can be formed above the posterior cruciate bed. This prevents the movement of the PCL from interfering with the recessed portion, avoids cutting the PCL after knee replacement, and thus avoids damage to the PCL, resulting in no postoperative discomfort for the patient.

[0006] The present invention also proposes a method for constructing a rear fork bed for an artificial knee joint liner.

[0007] The artificial knee joint liner of this invention includes a body fixed to the superior resection surface of the tibia. The body includes a medial support portion and a lateral support portion arranged opposite to each other in its width direction. The medial support portion and the lateral support portion respectively support the medial condyle and the lateral condyle of the femur. The posterior surface of the body is a posterior condylar surface, and the posterior condylar surface forms a posteriorly opening recess. The recess is located between the medial support portion and the lateral support portion. The recess is used to avoid the posterior cruciate ligament of the human body, and the surface of the recess is concave inward to form a posterior cruciate bed. The surface of the posterior cruciate bed extends upward in a direction away from the posterior condylar surface so that its upper space is adapted to the movement space of the posterior cruciate ligament of the human body.

[0008] The artificial knee joint liner of this invention has a medial support portion for supporting the medial condyle and a lateral support portion for supporting the lateral condyle. The posterior condylar surface of the body has a posteriorly opening recessed portion located between the medial and lateral support portions to avoid the posterior cruciate ligament. The surface of the recessed portion is concave inward to form a posterior cruciate bed. The surface of the posterior cruciate bed extends upward in a direction away from the posterior condylar surface. Thus, by forming the posterior cruciate bed by concave inward based on the recessed portion, and the orientation of the inclined posterior cruciate bed surface is consistent with the posterior cruciate ligament, a space that can accommodate the posterior cruciate ligament can be formed above the posterior cruciate bed. This prevents the movement of the posterior cruciate ligament from interfering with the recessed portion, avoids cutting of the posterior cruciate ligament after knee replacement, and avoids damage to the posterior cruciate ligament. The patient will not experience any discomfort after surgery.

[0009] In some embodiments, in the width direction of the body, the center of the recess is biased toward the inner support or the outer support.

[0010] In some embodiments, the rear fork bed includes an inner rear fork bed and an outer rear fork bed arranged symmetrically about the center of the body in the width direction of the body. The inner rear fork bed is adjacent to the inner support portion, and the outer rear fork bed is adjacent to the outer support portion. The space above the inner rear fork bed and the outer rear fork bed is adapted to the movement space of the posterior cruciate ligaments of the left and right legs of the human body, respectively.

[0011] In some embodiments, the surface of the rear fork bed is curved.

[0012] In some embodiments, the rear fork bed has a fan-shaped structure, and the center of the rear fork bed is located in the middle of the body in the width direction of the body.

[0013] In some embodiments, the angle between the sector projection of the rear fork bed on the horizontal plane and the horizontal plane is A, then 10° ≤ A ≤ 40°; and / or, the angle between the projection of the rear fork bed on the vertical plane and the horizontal plane is B, then 20° ≤ B ≤ 60°.

[0014] The present invention discloses a method for constructing a rear fork bed for an artificial knee joint liner, wherein the rear fork bed for an artificial knee joint liner is as described in claim 1. The construction method includes: defining a first projection plane parallel to the bottom surface of the body; defining a point on the projection point of the posterior condyle surface where it connects to the recessed portion on the first projection plane, adjacent to the side of the outer support portion, as the starting point of the generatrix; constructing a generatrix that extends upward and points towards the inner support portion with the starting point of the generatrix as the origin; and forming the rear fork bed by cutting the area where the solid and the liner intersect using a polygonal cross-section based on the constructed generatrix.

[0015] The rear fork bed construction method for artificial knee joint pads of the present invention, based on the structure of the pad of this application, selects the starting point of the generatrix and constructs the generatrix based on the starting point, and constructs the cutting entity according to the generatrix, so that the rear fork bed with precise dimensions can be cut on the body.

[0016] In some embodiments, the first projection plane is located 2mm-15mm below the lowest point of the upper surface of the outer support; and / or, the polygonal cross-section is circular or square.

[0017] In some embodiments, constructing an upwardly inclined, inwardly pointing generatrix pointing to the inner support portion with the starting point of the generatrix as the origin includes: defining a plane orthogonal to the first projection plane as a second projection plane, the centerline of the body in the width direction being located on the second projection plane; constructing a first projection line on the first projection plane at an angle α to the second projection plane, constructing a second projection line on the second projection plane at an angle b to the first projection plane, and using the first projection line and the second projection line as projections of the generatrix to deduce the spatial position of the generatrix.

[0018] In some embodiments, 5゜≤a≤20゜, and 20゜≤b≤60゜ Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a liner for an artificial knee joint according to an embodiment of the present invention.

[0020] Figure 2 This is an isometric view of a pad for an artificial knee joint according to an embodiment of the present invention.

[0021] Figure 3 This is a front view of a pad for an artificial knee joint according to an embodiment of the present invention.

[0022] Figure 4 This is an isometric view of a liner for an artificial knee joint according to an embodiment of the present invention, wherein the generatrix is ​​shown.

[0023] Figure 5 This is a schematic diagram of the structure of a liner for an artificial knee joint according to an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the structure of a pad for an artificial knee joint according to an embodiment of the present invention, showing the projection of the generatrix onto a horizontal projection plane.

[0025] Figure 7 This is a schematic diagram of the structure of a pad for an artificial knee joint according to an embodiment of the present invention, showing the projection of the generatrix onto a vertical projection plane.

[0026] Figure 8 This is a schematic diagram of the structure of a liner for an artificial knee joint according to another embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram of the structure of a liner for an artificial knee joint according to another embodiment of the present invention.

[0028] Figure 10 yes Figure 9 A cross-sectional view of the padding used in the artificial knee joint.

[0029] Figure label:

[0030] Body 1, inner support part 2, outer support part 3, recessed part 4, rear fork bed 5, inner rear fork bed 51, outer rear fork bed 52, first projection surface 6, generatrix 7, generatrix starting point 8, rear condyle surface 9. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] like Figures 1-10 As shown, the artificial knee joint liner of the present invention includes a body 1, which is fixed to the upper resection surface of the tibia. The body 1 includes a medial support portion 2 and a lateral support portion 3 that respectively support the medial and lateral condyles of the femur. The posterior surface of the body 1 is a posterior condylar surface 9, which has a recessed portion 4 that opens posteriorly. The recessed portion 4 is located between the medial support portion 2 and the lateral support portion 3. The recessed portion 4 is used to avoid the posterior cruciate ligament of the human body, and the surface of the recessed portion 4 is recessed inward to form a posterior cruciate bed 5. The surface of the posterior cruciate bed 5 extends upward in a direction away from the posterior condylar surface 9 so that the space above it is adapted to the movement space of the posterior cruciate ligament of the human body.

[0033] It should be noted that the posterior cruciate ligament (PCL) moves vertically in space with different body postures. Traditional pads only avoid the PCL through the recess on the posterior condyle 9. However, when the PCL swings up and down, the edge of the recess will come into contact with the PCL and cut it, which can easily cause discomfort or directly damage the PCL. In this application, a rear fork bed 5 is further constructed on the basis of the recess 4. The inclined rear fork bed 5 has the same orientation as the PCL, so a space that can accommodate the PCL can be formed above the rear fork bed 5. Since this space is adapted to the movement space of the PCL, the vertical swing of the PCL will not cut the edge of the rear fork bed 5.

[0034] The artificial knee joint liner of this invention has a main body 1 with a medial support portion 2 for supporting the medial condyle and a lateral support portion 3 for supporting the lateral condyle. The posterior condylar surface 9 of the main body 1 has a recessed portion 4 that opens posteriorly. The recessed portion 4 is located between the medial support portion 2 and the lateral support portion 3 to avoid the posterior cruciate ligament. The surface of the recessed portion 4 is recessed inward to form a posterior cruciate bed 5. The surface of the posterior cruciate bed 5 extends upward in a direction away from the posterior condylar surface 9. Thus, by forming the posterior cruciate bed 5 by being recessed inward based on the recessed portion 4, and the orientation of the inclined posterior cruciate bed 5 is consistent with the posterior cruciate ligament, a space that can accommodate the posterior cruciate ligament can be formed above the posterior cruciate bed 5. This prevents the movement of the posterior cruciate ligament from interfering with the recessed portion 4, avoids cutting of the posterior cruciate ligament after knee replacement, and avoids damage to the posterior cruciate ligament. The patient will not experience any discomfort after surgery.

[0035] Optionally, such as Figure 1 As shown, in the width direction of the body 1, the center of the recess 4 is offset towards the inner support portion 2 or the outer support portion 3. Optionally, as... Figure 9 As shown, in the width direction of the body 1, the center of the recess 4 is located at the midpoint between the inner support 2 and the outer support 3. Specifically, the configuration of the recess 4 can be adaptively selected according to the needs of different patients.

[0036] Preferably, in some embodiments, such as Figure 8 As shown, the rear fork bed 5 includes an inner rear fork bed 51 and an outer rear fork bed 52 arranged symmetrically about the center of the body 1 in the width direction. The inner rear fork bed 51 is adjacent to the inner support part 2, and the outer rear fork bed 52 is adjacent to the outer support part 3. The space above the inner rear fork bed 51 and the outer rear fork bed 52 are respectively adapted to the movement space of the posterior cruciate ligaments of the left and right legs. Therefore, the pad of this application can be used in knee replacement surgery of both legs, without the need for separate manufacturing, reducing design and production costs. Moreover, there is no need to classify and screen the pads for the left and right legs during surgery, resulting in high surgical efficiency.

[0037] Preferably, the surface of the rear fork bed 5 is curved. The curved structure has a high degree of matching with the outer peripheral surface of the ligament, which can provide better support for the ligament.

[0038] Optionally, to ensure that the padding of this application can be used indiscriminately for knee replacements of both legs, the padding is not limited to being configured as follows: Figure 8 The two mirror-arranged examples shown are, for example, as... Figure 9 As shown, the rear fork bed 5 has a fan-shaped structure, and in the width direction of the body 1, the center of the rear fork bed 5 is located at the middle of the total width of the pad. It can be understood that the inner support part 2 and the outer support part 3 are in the same position relative to the fan-shaped rear fork bed 5. Therefore, when applied to knee replacement on different sides, the rear fork bed 5 can accommodate the posterior cruciate ligament without the need for separate design for left and right legs.

[0039] Furthermore, such as Figure 9 As shown, the included angle of the sector projection of the posterior cruciate ligament 5 on the horizontal plane is A, then 10° ≤ A ≤ 40°. In other words, the opening angle of the sector-shaped posterior cruciate ligament 5 is between 10 degrees and 40 degrees. The inventors have found through research that when the opening angle of the sector-shaped posterior cruciate ligament 5 is within the above range, the width of the posterior cruciate ligament 5 can accommodate the range of motion of the posterior cruciate ligament in the horizontal direction for most patients.

[0040] Furthermore, such as Figure 10 As shown, the angle between the projection of the rear fork bed 5 onto the vertical plane and the horizontal plane is B, then 20° ≤ B ≤ 60°. In other words, the tilt angle of the rear fork bed 5 is between 20 degrees and 60 degrees. The inventors discovered through research that when the tilt angle of the fan-shaped rear fork bed 5 is within the above range, the extension direction of the bed surface of the rear fork bed 5 is roughly consistent with the extension direction of the posterior cruciate ligament, which facilitates the adaptation of the posterior cruciate ligament's range of motion in vertical space.

[0041] The method for constructing the rear fork bed 5 of the artificial knee joint pad according to an embodiment of the present invention includes: defining a first projection plane 6 parallel to the bottom surface of the body 1. Figure 2 (See the XY plane shown). Then, define the point on the projection point of the rear condyle 9 and the recessed part 4 on the first projection plane 6 that is adjacent to the outer support part 3 as the starting point 8 of the generatrix. Then, construct a generatrix 7 that extends upward and points towards the inner support part 2 with the starting point 8 of the generatrix as the origin. Finally, based on the constructed generatrix 7, use a polygonal section to generate the intersection area of ​​the solid and the pad to cut and form the rear fork bed 5.

[0042] The rear fork bed 5 of the artificial knee joint liner of the present invention, based on the structure of the liner of this application, selects the starting point 8 of the generatrix and constructs the generatrix 7 with the starting point, and constructs the cutting entity according to the generatrix 7, so that the rear fork bed 5 with precise dimensions can be cut on the body 1.

[0043] Optionally, the polygonal cross-section can be circular or square.

[0044] Furthermore, the first projection surface 6 is located 2mm-15mm below the lowest point of the upper surface of the outer support portion 3.

[0045] Furthermore, the busbar 7, which extends upwards and points towards the inner support 2 with the starting point 8 as the origin, includes:

[0046] Define the plane orthogonal to the first projection plane 6 as the second projection plane. Figure 2 (as shown in the YZ plane), the centerline of body 1 in the width direction is located on the second projection plane;

[0047] A first projection line is constructed on the first projection plane 6 at an angle α to the second projection plane, and a second projection line is constructed on the second projection plane at an angle b to the first projection plane 6. The spatial position of the generatrix 7 is derived by using the first and second projection lines as projections of the generatrix 7.

[0048] Specifically, 5° ≤ a ≤ 20°, and 20° ≤ b ≤ 60°. That is, the spatial position of the constructed generatrix 7 is such that it tilts upwards at a rate of 5 to 20 degrees from the starting point 8, and tilts towards the inner support 2 at a rate of 20 to 60 degrees. The inventors discovered that the posterior cruciate ligament (PCL) bed 5 cut from the generatrix 7 within the above range precisely matches the extension direction and range of motion of the posterior cruciate ligament, thus better avoiding the PCL and meeting the knee replacement needs of most patients.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A pad for an artificial knee joint, characterized in that, The device includes a body fixed to the superior resection surface of the tibia. The body includes a medial support portion and a lateral support portion arranged opposite each other in its width direction. The medial support portion and the lateral support portion respectively support the medial condyle and the lateral condyle of the femur. The posterior surface of the body is a posterior condylar surface, which forms a posteriorly opening recess located between the medial support portion and the lateral support portion. The recess is used to avoid the posterior cruciate ligament of the human body, and the surface of the recess is concave inward to form a posterior cruciate bed. The surface of the posterior cruciate bed extends upward in a direction away from the posterior condylar surface so that its upper space is adapted to the movement space of the posterior cruciate ligament of the human body. The method for constructing the rear fork bed for the artificial knee joint pad includes: Define a first projection plane parallel to the bottom surface of the body, and define the point on the side of the outer support portion adjacent to the projection point of the rear condyle where it connects with the recessed portion on the first projection plane as the starting point of the generatrix. A busbar is constructed with the starting point of the busbar as the origin, extending upwards and pointing towards the inner support. Based on the constructed busbar, the rear fork bed is formed by cutting the area where the solid and the pad intersect using a polygonal cross section; The busbar that is constructed with the starting point of the busbar as the origin, extending upwardly at an inward angle and pointing towards the inner support includes: A plane orthogonal to the first projection plane is defined as the second projection plane, and the centerline of the body in the width direction is located on the second projection plane; A first projection line is constructed on the first projection plane at an angle α to the second projection plane, and a second projection line is constructed on the second projection plane at an angle b to the first projection plane. The spatial position of the generatrix is ​​derived by projecting the first projection line and the second projection line as projections of the generatrix.

2. The artificial knee joint liner according to claim 1, characterized in that, In the width direction of the body, the center of the recess is biased toward the inner support or the outer support.

3. The artificial knee joint liner according to claim 1, characterized in that, The rear fork bed includes an inner rear fork bed and an outer rear fork bed arranged symmetrically about the center of the body in the width direction of the body. The inner rear fork bed is adjacent to the inner support part, and the outer rear fork bed is adjacent to the outer support part. The space above the inner rear fork bed and the outer rear fork bed are respectively adapted to the movement space of the posterior cruciate ligaments of the left and right legs of the human body.

4. The artificial knee joint liner according to claim 1, characterized in that, The surface of the rear fork bed is curved.

5. The artificial knee joint liner according to claim 1, characterized in that, The rear fork bed has a fan-shaped structure, and the center of the rear fork bed is located in the middle of the body in the width direction of the body.

6. The artificial knee joint liner according to claim 5, characterized in that, If the included angle of the sector projection of the rear fork bed on the horizontal plane is A, then 10° ≤ A ≤ 40°; And / or, if the angle between the projection of the rear fork bed onto the vertical plane and the horizontal plane is B, then 20° ≤ B ≤ 60°.

7. The artificial knee joint liner according to claim 1, characterized in that, The first projection plane is located 2mm-15mm below the lowest point of the upper surface of the outer support; And / or, the polygonal cross-section is circular or square.

8. The artificial knee joint liner according to claim 1, characterized in that, The range of the included angle α is: 5° ≤ a ≤ 20°, and the range of the included angle β is: 20° ≤ b ≤ 60°.

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