CN117243733A

CN117243733A - Artificial knee joint prosthesis and design method thereof

Info

Publication number: CN117243733A
Application number: CN202311263251.4A
Authority: CN
Inventors: 张书玮
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-09-27
Filing date: 2023-09-27
Publication date: 2023-12-19

Abstract

The invention relates to an artificial knee joint prosthesis, which comprises a femur prosthesis and a tibia prosthesis, wherein the femur prosthesis is provided with a femur inner condyle part and a femur outer condyle part, the femur inner condyle part is provided with a first joint surface, the femur outer condyle part is provided with a second joint surface which is a convex curved surface in the shape of a part conical surface, the tibia prosthesis is provided with a medial tibia platform part and a lateral tibia platform part, the medial tibia platform part is provided with a third joint surface, the lateral tibia platform part is provided with a fourth joint surface, the fourth joint surface is a convex curved surface in the shape of a part conical surface, the first joint surface and the third joint surface form a ball-and-socket joint, the second joint surface and the fourth joint surface form a cone-wheel group joint, and the central axis of the second joint surface and the central axis of the fourth joint surface are all arranged at the center of the ball-and-socket joint. The invention also provides a design method of the artificial knee joint prosthesis. The invention can improve the use effect of the artificial knee joint prosthesis and reduce the manufacturing difficulty of the artificial knee joint prosthesis.

Description

Artificial knee joint prosthesis and design method thereof

Technical Field

The invention relates to medical equipment, in particular to an artificial knee joint prosthesis and a design method thereof.

Background

The knee joint is composed of a femur distal end, a tibia proximal end and a patella. Wherein the patella and the femur pulley form a patellofemoral joint, and the femur inner and outer condyles and the tibia inner and outer platforms form an inner and outer tibia femoral joint respectively.

The ligament structure of the knee joint mainly comprises a medial collateral ligament existing on the inner side of the knee joint and a lateral collateral ligament existing on the outer side of the knee joint, and the ligament structure mainly has the function of limiting the internal and external turning of the knee joint. The anterior and posterior cruciate ligaments of the knee joint exist in the knee joint and mainly play a role in stabilizing the knee joint during flexion and extension and rotation movements.

The perfect match of the high degree of anastomosis between the articular surfaces of the knee joint with the function of the ligaments of the knee joint is the anatomical basis for the knee joint to perform various movements. The knee joint of the human body can not only complete the bending and stretching movement, but also simultaneously complete the rotation movement taking the inner side of the knee joint as a pivot. The movement characteristics of the knee joint of a human body are determined by the shape of the joint surface of the knee joint and the function of the ligament of the knee joint, and the movement function of the knee joint of the human body can be adversely affected by the damage of any one component. Advanced knee osteoarthritis manifests itself mainly as cartilage wear, with most knee ligaments intact, and a small proportion of patients' anterior cruciate ligaments damaged, denatured or destroyed, which can restore anterior cruciate ligament function by ligament reconstruction techniques. If the surface morphology of the knee joint of the patient with advanced knee osteoarthritis can be rebuilt, the physiological function of the knee joint ligament can be recovered, and then the physiological function of the knee joint of the human body can be recovered. Therefore, restoring the surface morphology of the knee joint is a viable way to restore normal function of the knee joint. Knee replacement is to replace severely worn cartilage with an artificial knee prosthesis, thereby relieving knee pain and improving knee function.

The knee prosthesis includes a femoral component for coupling to the femur, a tibial component for coupling to the tibia, and a tibial insert positioned over the tibial component for articulating with the femoral component. The condyle surface of the femoral component and the bearing surface of the tibial insert undergo relative anterior-posterior displacement and medial-lateral rotation as the knee prosthesis moves. If the disease of the knee joint only affects the compartment on one side of the knee joint, the artificial knee joint which only replaces the cartilage of the compartment on one side of the knee joint is a unicondylar. It also includes a femoral component, a tibial component, and a tibial insert above the tibial component and coupled to the femoral component joint. Restoring the knee joint movement function as much as possible, ensuring the stability of the knee joint and reducing the abrasion of the knee joint prosthesis in the movement process are main targets of the knee joint prosthesis design.

In the prior art, the joint surfaces of the medial femoral condyle and the lateral femoral condyle of the artificial knee joint prosthesis are generally designed to be convex curved surfaces, the joint surfaces of the tibial gasket, the medial femoral condyle and the lateral femoral condyle are generally designed to be concave curved surfaces, and the artificial knee joint prosthesis is installed by adopting the principle of knee joint flexion, extension gap balance and surrounding soft tissue balance to perform osteotomy. By adopting the scheme, the following technical problems exist:

the function of the knee ligament is damaged, and the existing artificial knee replacement needs to cut off the anterior cruciate ligament or cut off the anterior and posterior cruciate ligaments simultaneously. The original surface morphology of the knee joint cannot be recovered, the inner femoral condyle is approximately spherical, and forms a ball-and-socket joint with the inner tibial plateau, but the morphological characteristics of the outer femoral condyle and the outer tibial plateau are poorly known, and anatomic reconstruction is not considered. The physiological activities of the knee joint cannot be recovered, and the patient cannot squat normally after operation. The two condyle articular surfaces of the modern artificial knee joint prosthesis are made into ball joints (or approximate ball joints) so as to increase the stability of the artificial knee joint, not only can the inherent form of the artificial knee joint be changed, but also excessive compensation or dislocation compensation of the lost bone mass can be caused, particularly, the rear edge of the outer side gasket of the tibial plateau after the replacement operation is higher than the rear edge of the outer side gasket of the original tibial plateau, the posterior cruciate ligament is required to be loosened or cut off, and the postoperative cruciate ligament cannot play the original role. Even if the unicondylar replacement is carried out (the ligament structure of the knee joint is not damaged), the original joint form of the knee joint cannot be recovered, the artificial joint has poor function, and the premature loosening or serious abrasion of the joint is difficult to avoid. The joint surfaces of the existing artificial joint prosthesis are curved surfaces with complex shapes, so that the manufacturing difficulty is high and the manufacturing period is long.

Disclosure of Invention

The object of the present invention is to propose an artificial knee joint prosthesis and a method for designing the same, which alleviate or eliminate at least one of the above mentioned technical problems.

The invention discloses an artificial knee joint prosthesis, which comprises a femoral prosthesis and a tibial prosthesis, wherein the femoral prosthesis is provided with a femoral inner condyle and a femoral outer condyle, the femoral inner condyle is provided with a first joint surface, the femoral outer condyle is provided with a second joint surface, the first joint surface is a part spherical convex curved surface, the second joint surface is a part conical convex curved surface, the tibial prosthesis is provided with an inner tibial plateau and an outer tibial plateau, the inner tibial plateau is provided with a third joint surface, the outer tibial plateau is provided with a fourth joint surface, the third joint surface is a part spherical concave curved surface, the fourth joint surface is a part conical convex curved surface, the first joint surface and the third joint surface form a cone-shaped joint, the second joint surface and the fourth joint surface form a cone-shaped joint, and the central axis of the second joint surface and the central axis of the fourth joint surface pass through the center of the ball socket joint.

Optionally, the central axis of the second articular surface and the central axis of the fourth articular surface intersect, and the intersection point is located at the center of the ball-and-socket joint.

Optionally, the intersection point coincides with a center point of the ball-and-socket joint.

Optionally, an included angle between the central axis of the second joint surface and the central axis of the fourth joint surface is greater than or equal to 87 ° and less than or equal to 93 °.

Optionally, the central axis of the fourth articular surface is parallel to a tibial centerline corresponding to the tibial prosthesis.

The invention also provides a design method of the artificial knee joint prosthesis, which is used for designing any artificial knee joint prosthesis and comprises the following steps:

obtaining a cross-sectional view of a knee joint to be replaced, wherein the cross-sectional view comprises a femoral medial condyle contour line, a femoral lateral condyle contour line, a medial tibial plateau contour line and a lateral tibial plateau contour line, the femoral medial condyle contour line comprises a femoral medial condyle joint line, the femoral lateral condyle contour line comprises a femoral lateral condyle joint line, the medial tibial plateau contour line comprises a medial tibial plateau joint line, and the lateral tibial plateau contour line comprises a lateral tibial plateau joint line;

determining a fitting circle of the femoral medial condyle joint line and a circle center of the fitting circle based on the cross-sectional view;

determining a clearance line between the femoral external condyle articular line and the external tibial plateau articular line based on the cross-sectional view, the clearance line being a straight line passing through the center of the circle;

determining a tibial centerline of the knee joint to be replaced based on the cross-sectional view;

a first axis that passes through the center of the circle and is parallel to the tibial centerline based on the cross-sectional view;

based on the sectional view, a second axis which passes through the center of the circle and is perpendicular to the first axis;

the circle center is taken as a sphere center, and the radius of the fitting circle is taken as a radius, so that the first joint surface and the third joint surface are designed;

designing the fourth joint surface by taking the first axis as a central axis and taking a first straight line section collinear with the clearance line as a bus;

the second joint surface is designed with the second axis as a central axis and a second straight line segment collinear with the clearance line as a generatrix.

Optionally, the method further comprises the following steps: an intersection of the first axis and the medial tibial plateau joint line is determined based on the cross-sectional view.

Optionally, the method further comprises the following steps: based on the cross-sectional view, a first auxiliary straight line perpendicular to the tibial centerline and passing through the intersection of the first axis and the medial tibial plateau axis, a lateral intersection of the first auxiliary straight line and the lateral tibial plateau contour line, and a second auxiliary straight line parallel to the tibial centerline passing through the intersection are determined.

Optionally, the cross-sectional view is a median coronal plane nuclear magnetic resonance image or a median coronal plane CT image of the knee joint to be replaced.

The invention is based on a new theory provided by the inventor, and the theory provides that the joint between the knee joint femur and the tibia is composed of two joints, and the femoral internal condyle and the tibia internal platform form a ball-and-socket joint at the inner side of the knee joint; the femur external condyle and the tibia external plateau are respectively a part of two conical surfaces, the two conical surfaces form an external joint of the knee joint, and the central axes of the two external conical surfaces intersect at the central point of the ball-and-socket joint at the inner side of the knee joint.

The invention has the following characteristics: the artificial knee joint prosthesis which is more in accordance with the motion rule of the human knee joint can be better matched with the knee joint of a patient, and the use effect of the artificial knee joint prosthesis can be improved; by adopting the artificial knee joint prosthesis provided by the invention, the anterior cruciate ligament and the posterior cruciate ligament of the knee joint can play the original roles, and the use effect of the artificial knee joint prosthesis can be ensured; the joint surface of the artificial joint prosthesis provided by the invention is simple in shape, and the manufacturing difficulty of the artificial joint prosthesis is reduced.

Drawings

FIG. 1 is a cross-sectional view of an artificial knee prosthesis according to one embodiment;

FIG. 2 is an exploded view of an artificial knee prosthesis according to one embodiment;

FIG. 3 is a cross-sectional view of a femoral prosthesis according to an embodiment;

FIG. 4 is a cross-sectional view of a tibial prosthesis according to one embodiment;

fig. 5 is a schematic diagram of the geometric construction of the artificial knee prosthesis design method described in the detailed description.

In the figure: 1-femoral prosthesis; 2-tibial prosthesis; 3-femur; 4-tibia; 5-fibula; 6-tibia centerline; 7-circle center; 8—a first axis; 9-a second axis; 10-gap line; 11-fitting a circle; 12-a first intersection point; 13-a first auxiliary straight line; 14-a second intersection point; 15-a second auxiliary straight line; 16-a third auxiliary straight line;

101-femoral medial condyle; 102-femoral lateral condyle; 103—a first articular surface; 104-a second articular surface; 105-meniscus mating face; 201-medial tibial plateau; 202-lateral tibial plateau; 203-a third articular surface; 204-fourth articular surface; 301-femoral medial condyle articular line; 302-femoral lateral condyle articular line; 401-medial tibial plateau joint line; 402-lateral tibial plateau joint line.

Detailed Description

Further advantages and effects of the present invention will become readily apparent to those skilled in the art from the disclosure herein, by referring to the accompanying drawings and the preferred embodiments. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be understood that the preferred embodiments are presented by way of illustration only and not by way of limitation.

It should be noted that the illustrations provided in the following embodiments merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.

1-4, an artificial knee joint prosthesis comprises a femoral prosthesis 1 and a tibial prosthesis 2, wherein the femoral prosthesis 1 is provided with a femoral medial condyle part 101 and a femoral lateral condyle part 102, the femoral medial condyle part 101 is provided with a first joint surface 103, the femoral lateral condyle part 102 is provided with a second joint surface 104, the first joint surface 103 is a convex curved surface with a partial spherical surface, the second joint surface 104 is a convex curved surface with a partial conical surface, the tibial prosthesis 2 is provided with a medial tibial plateau part 201 and a lateral tibial plateau part 202, the medial tibial plateau part 201 is provided with a third joint surface 203, the lateral tibial plateau part 202 is provided with a fourth joint surface 204, the third joint surface 203 is a concave curved surface with a partial spherical surface, the fourth joint surface 204 is a convex curved surface with a partial conical surface, the first joint surface 103 and the third joint surface 203 form a ball-and socket joint, and the second joint surface 104 and the fourth joint surface 204 form a cone-shaped joint; the central axis of the second articular surface 104 and the central axis of the fourth articular surface 204 both pass through the centers of the ball-and-socket joints to enable the femoral prosthesis 1 and the tibial prosthesis 2 to simultaneously rotate and roll about the central axis of the second articular surface 104 and the central axis of the fourth articular surface 204. Since the joint formed by the first joint surface 103 and the third joint surface 203 is a ball-and-socket joint, the first joint surface 103 and the third joint surface 203 maintain a stable state when the femoral prosthesis 1 and the tibial prosthesis 2 relatively rotate and roll about the central axis of the second joint surface 104 and the central axis of the fourth joint surface.

By adopting the technical scheme, in the first aspect, through reasonably arranging the joint surfaces of the femoral prosthesis 1 and the tibial prosthesis 2, a ball-and-socket joint is formed at the inner side of the artificial knee joint prosthesis, a cone pulley-shaped joint is formed at the outer side of the artificial knee joint prosthesis, and the central axis of the second joint surface 104 and the central axis of the fourth joint surface 204 are both arranged to be through the center of the ball-and-socket joint, so that the ball-and-socket joint and the cone pulley-shaped joint can move together in a harmonious manner, the artificial knee joint prosthesis not only can complete the bending and stretching movement of the knee joint, but also can complete the rotation movement of the knee joint, and can also be accompanied with the rotation movement at the same time as completing the bending and stretching movement, thereby being more in line with the movement rule of the human knee joint prosthesis, being capable of better matching with the knee joint of a patient, being capable of improving the use effect of the artificial knee joint prosthesis, being capable of ensuring the movement stability of the artificial knee joint prosthesis and reducing the possibility of wearing in the movement process of the artificial knee joint prosthesis. In the second aspect, the second joint surface 104 and the fourth joint surface 204 are convex curved surfaces with partial conical surfaces, so that the bionic design is performed on the surface form of the original knee joint, the problem that the rear edge of the artificial knee joint tibial plateau is higher than that of the original tibial plateau is avoided, and the function of the posterior cruciate ligament can be better reserved without loosening or cutting off the posterior cruciate ligament when the knee joint surface replacement is performed, so that the use effect of the artificial knee joint prosthesis is ensured. In a third aspect, the first joint surface 103 is a convex curved surface with a partial spherical surface shape, the second joint surface 104 is a convex curved surface with a partial conical surface shape, the third joint surface 203 is a concave curved surface with a partial spherical surface shape, the fourth joint surface 204 is a convex curved surface with a partial conical surface shape, the joint surfaces are all regular curved surfaces, the joint surfaces are simple in shape, the manufacturing difficulty of the artificial joint prosthesis is reduced, and the manufacturing time of the artificial joint prosthesis can be shortened.

The partial spherical surface refers to a part of the curved surface of the spherical surface, and the partial conical convex curved surface refers to a part of the curved surface of the conical surface; the central axis of the second articular surface 104 is collinear with the central axis of the conical surface corresponding to the second articular surface 104 and the central axis of the fourth articular surface 204 is collinear with the central axis of the conical surface corresponding to the fourth articular surface 204.

In some embodiments, the central axis of the second articular surface 104 and the central axis of the fourth articular surface 204 intersect, and the intersection point is located at the center of the ball-and-socket joint. By adopting the technical scheme, the femoral prosthesis 1 and the tibial prosthesis 2 can perform better and more stable relative movement, and the ball-and-socket joint and the cone pulley group joint can perform stable and harmonious movement.

In some embodiments, the central axis of the second articular surface 104 is substantially perpendicular to the central axis of the fourth articular surface 204. In particular implementations, the included angle of the central axis of the second articular surface 104 and the central axis of the fourth articular surface 204 is greater than or equal to 87 ° and less than or equal to 93 ° such that the central axis of the second articular surface 104 is substantially perpendicular to the central axis of the fourth articular surface 204.

In some embodiments, the central axis of the fourth articular surface 204 is parallel to the tibial centerline 6 corresponding to the tibial prosthesis 2.

As a preferred example, the central axis of the second articular surface 104 and the central axis of the fourth articular surface 204 intersect, the intersection point coincides with the central point of the ball-and-socket joint, the central axis of the second articular surface 104 is perpendicular to the central axis of the fourth articular surface 204, and the central axis of the fourth articular surface 204 is parallel to the tibial centerline 6 corresponding to the tibial prosthesis 2. By adopting the technical scheme, the ball-and-socket joint and the cone pulley group joint can move together in harmony.

The invention also provides a design method of the artificial knee joint prosthesis, which is used for designing the artificial knee joint prosthesis, the design method of the artificial knee joint prosthesis can also be used for designing the artificial knee joint lateral unicondylar prosthesis, and the design method of the artificial knee joint prosthesis comprises the following steps:

step one, obtaining a cross-sectional view of a knee joint to be replaced, wherein the cross-sectional view comprises a femoral medial condyle contour line, a femoral lateral condyle contour line, a medial tibial plateau contour line and a lateral tibial plateau contour line, the femoral medial condyle contour line comprises a femoral medial condyle joint line 301, the femoral lateral condyle contour line comprises a femoral lateral condyle joint line 302, the medial tibial plateau contour line comprises a medial tibial plateau joint line 401, and the lateral tibial plateau contour line comprises a lateral tibial plateau joint line 402;

step two, determining a fitting circle 11 of the femoral internal condyle joint line 301 and a circle center 7 of the fitting circle 11 based on the sectional view;

step three, based on the sectional view, determining a clearance line 10 between the femoral external condyle joint line 302 and the lateral tibial plateau joint line 402, wherein the clearance line 10 is a straight line passing through the circle center 7, and the clearance line 10 can be formed by fitting based on the central line of the clearance between the femoral external condyle joint line 302 and the lateral tibial plateau joint line 402;

determining a tibia central line 6 of the knee joint to be replaced based on the sectional view;

a fifth step of making a first axis 8 which passes through the center 7 of the circle and is parallel to the tibia central line 6 based on the sectional view;

step six, based on the sectional view, a second axis 9 which passes through the center 7 and is perpendicular to the first axis 8;

step seven, taking the circle center 7 as a sphere center, and taking the radius of the fitting circle 11 as a radius, and designing a first joint surface 103 and a third joint surface 203;

step eight, designing a fourth joint surface 204 by taking the first axis 8 as a central axis and taking a first straight line section collinear with the clearance line 10 as a bus;

step nine, the second joint surface 104 is designed by taking the second axis 9 as a central axis and taking a second straight line section which is collinear with the clearance line 10 as a bus bar.

As shown in fig. 1 to 5, by adopting the above artificial knee joint prosthesis design method, the center and radius of the ball-and-socket joint, the center axis and bus of the second joint surface 104 and the center axis and bus of the fourth joint surface 204 can be rapidly determined based on the knee joint to be replaced, and the artificial knee joint prosthesis with high matching degree with the knee joint to be replaced can be rapidly designed based on the determined center, radius, center axis and bus.

In particular implementations, the length of the first straight line segment may be set according to the extent of lateral tibial plateau joint line 402 and the length of the second straight line segment may be set according to the extent of femoral lateral condyle joint line 302. The third articular surface 203 is a concave cambered surface, the radius of the third articular surface 203 is the same as the radius of the femoral medial condyle fitting circle 11, and the height of the third articular surface 203 is flush (or slightly lower) with the apex of the medial intercondylar spine of the tibial plateau. The medial side of the fourth articular surface 204 is flush with (or slightly lower than) the vertex of the intercondylar spine on the lateral side of the tibial plateau, the lateral side reaches the outer edge of the tibial plateau, the front edge ends at the intersection point of the extension line of the central line of the first articular surface 103 and the third articular surface 203 forming the center of the ball-and-socket joint and the tibial dead center of the anterior cruciate ligament and the front lateral edge of the tibial plateau, and the rear edge ends at the intersection point of the extension line of the central line of the first articular surface 103 and the third articular surface 203 forming the center of the ball-and-socket joint and the tibial dead center of the posterior cruciate ligament and the rear edge of the tibial plateau.

In some embodiments, the artificial knee prosthesis design method further includes the step of determining an intersection of the first axis 8 and the medial tibial plateau joint line 401 based on the cross-sectional view, the intersection being the first intersection 12, the first intersection 12 being the lowest point of the third articular surface 203.

In some embodiments, the artificial knee prosthesis design method further comprises step eleven: based on the cross-sectional view, a first auxiliary straight line 13 perpendicular to the tibial centerline 6 and passing through the first intersection point 12, a lateral intersection point of the first auxiliary straight line 13 with the lateral tibial plateau contour is determined, the intersection point being a second intersection point 14, and a second auxiliary straight line 15 parallel to the tibial centerline 6 and passing through the second intersection point 14.

In some embodiments, the artificial knee prosthesis design method further comprises step twelve: based on the sectional view, the center 7 is crossed to a third auxiliary straight line 16 symmetrical to the clearance line 10, and the symmetrical line is a second axis 9. The triangle defined by the first axis 8, the clearance line 10 and the first auxiliary straight line 13 is half of the cross section of the conical surface where the fourth joint surface 204 is located. The triangle defined by the second axis 9, the clearance line 10 and the second auxiliary straight line 15 is half the cross section of the conical surface where the second joint surface 104 is located. The triangle defined by the third auxiliary straight line 16, the clearance line 10 and the second auxiliary straight line 15 is the cross section of the conical surface where the second joint surface 104 is located, and the diameter of the circular bottom of the conical surface is basically equal to the diameter of the fitting circle 11.

In some embodiments, the cross-sectional view is a median coronal plane nuclear magnetic resonance or median coronal plane CT image of the knee joint to be replaced. In particular implementations, the contour lines of the components of the knee joint to be replaced may be extracted from the nmr image of the coronal region of the knee joint to be replaced, and the fitted circle 11, the tibial centerline 6, and the second axis 9 of the first axis 8 may be determined by mapping based on the extracted contour lines.

In some embodiments, the lateral femoral condyle 102 is provided with a meniscus mating surface 105, and the gap formed between the meniscus mating surface 105 and the lateral tibial plateau 202 may accommodate the popliteal tendon. The meniscus mating surface 105 also facilitates the formation of a articular surface with the patella.

In some embodiments, to more accurately determine the gap line 10, the gap line 10 is determined as the gap between the medial half length segment of the femoral lateral condyle articular line 302 and the medial half length segment of the lateral tibial plateau articular line 402.

In practice, in order to design a better artificial knee prosthesis, the nuclear magnetic resonance (or CT) image of the knee to be replaced has the following requirements: the lateral tibial plateau joint line 402 and the femoral lateral condyle joint line 302 have the greatest slope, the lateral meniscus cross section is the smallest, and the femoral medial condyle cross section is the greatest. That is, the cut-out of the cross-sectional view of the knee to be replaced is the portion where the knee lateral tibial plateau joint line 402 and the femoral lateral condyle joint line 302 are at the greatest slope, the lateral meniscus cross-section is at the smallest, and the femoral medial condyle cross-section is at the greatest. As shown in fig. 5, in practice, the nmr image can show the femur 3, tibia 4, and fibula 5.

The root cause of unsatisfactory artificial knee joint replacement at present is that the solution structure and ligament function of the knee joint of a person are lack of deep knowledge, the morphological difference of the medial condyle and the lateral condyle of the knee joint and the medial and lateral tibial plateau is not fully recognized, the medial condyle and the lateral condyle of the artificial knee joint are designed to be approximately spherical, and a ball socket joint is formed by the medial condyle and the lateral condyle and the medial plateau of the artificial knee joint, which is different from the real knee joint. The inventor realizes that the medial femoral condyle and the medial tibial plateau form a ball-and-socket joint on the basis of fully understanding the function and the surface morphology of the knee joint of a normal person, the lateral femoral condyle and the lateral tibial plateau form a cone pulley joint, and the intersection point of the axes of the two cone pulleys coincides with the center of the ball-and-socket joint formed by the medial femoral condyle and the medial tibial plateau. The new point of view breaks the rule of knee joint dissection and movement, and the artificial knee joint prosthesis designed by using the rule can further improve the treatment effect of artificial knee joint replacement, and can maintain the long-term stability of the artificial knee joint while restoring the movement function of the knee joint.

The above embodiments are merely preferred embodiments for fully explaining the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutions and modifications will occur to those skilled in the art based on the present invention, and are intended to be within the scope of the present invention. In the description of the present specification, a description referring to the terms "one embodiment," "some embodiments," "examples," "particular examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the invention in connection with the embodiment or example. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.

Claims

1. An artificial knee joint prosthesis, which is characterized in that,

comprising a femur prosthesis and a tibia prosthesis,

the femoral prosthesis is provided with a femoral inner condyle and a femoral outer condyle, the femoral inner condyle is provided with a first joint surface, the femoral outer condyle is provided with a second joint surface, the first joint surface is a convex curved surface in a partial spherical shape, and the second joint surface is a convex curved surface in a partial conical shape;

the tibia prosthesis is provided with an inner tibia platform part and an outer tibia platform part, the inner tibia platform part is provided with a third joint surface, the outer tibia platform part is provided with a fourth joint surface, the third joint surface is a concave curved surface which is in a partial spherical shape, and the fourth joint surface is a convex curved surface which is in a partial conical shape;

the first joint surface and the third joint surface form a ball-and-socket joint, the second joint surface and the fourth joint surface form a cone-wheel group joint, and the central axis of the second joint surface and the central axis of the fourth joint surface pass through the center of the ball-and-socket joint.

2. The artificial knee joint prosthesis of claim 1, wherein the central axis of the second articular surface and the central axis of the fourth articular surface intersect and the intersection point is located at the center of the ball and socket joint.

3. The artificial knee joint prosthesis of claim 2, wherein the intersection point coincides with a center point of the ball and socket joint.

4. The artificial knee joint prosthesis of claim 1, wherein the central axis of the second articular surface and the central axis of the fourth articular surface are angled greater than or equal to 87 ° and less than or equal to 93 °.

5. The artificial knee joint prosthesis of claim 1, wherein the central axis of the fourth articular surface is parallel to a tibial centerline corresponding to the tibial prosthesis.

6. A method of designing an artificial knee prosthesis, for designing an artificial knee prosthesis according to any one of claims 1 to 5, comprising the steps of:

7. The artificial knee joint prosthesis of claim 6, further comprising the steps of: an intersection of the first axis and the medial tibial plateau joint line is determined based on the cross-sectional view.

8. The artificial knee joint prosthesis of claim 7, further comprising the steps of: based on the cross-sectional view, a first auxiliary straight line perpendicular to the tibial centerline and passing through the intersection of the first axis and the medial tibial plateau axis, a lateral intersection of the first auxiliary straight line and the lateral tibial plateau contour line, and a second auxiliary straight line parallel to the tibial centerline passing through the intersection are determined.

9. The artificial knee prosthesis of claim 6, wherein the cross-sectional view is a median coronal plane nuclear magnetic resonance image or a median coronal plane CT image of the knee joint to be replaced.