Tibial spacer and knee prosthesis

Abstract

This invention discloses a tibial liner and a knee joint prosthesis. The tibial liner includes a medial fossa and a lateral fossa. The posterior end of the medial fossa has a medial posterior lip, and the posterior end of the lateral fossa has a lateral posterior lip. The upper end of the lateral posterior lip has a cross-sectional area, the outer side of which is not higher than the inner side, and the front end of which is not higher than the rear end. The tibial liner of this invention has a reasonable structural design and good performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a tibial pad and a knee prosthesis. BACKGROUND

[0002] Knee replacement surgery uses an artificial knee prosthesis to replace the diseased articular cartilage and meniscus while retaining the normal joint ligaments and other tissues, thereby having the advantages of small trauma, fast recovery, reduced pain, and more natural range of motion, etc., so knee replacement surgery is widely used in knee joint treatment.

[0003] In the related art, due to the unreasonable structure design between the femoral prosthesis and the tibial pad, when the human body is in a high flexion condition, the posterior condyle part of the lateral condyle of the femoral prosthesis will contact the posterior articular surface of the lateral articular surface of the tibial pad and the posterior corner of the pad, thereby limiting the rotation of the knee joint, and easily causing the stress of the bone cement to increase, thereby increasing the risk of prosthesis loosening. SUMMARY

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

[0005] To this end, an embodiment of the present application proposes a tibial pad with a reasonable structure design and good use effect.

[0006] An embodiment of the present application also proposes a knee prosthesis.

[0007] The tibial pad of an embodiment of the present application comprises: a medial fossa and a lateral fossa, a medial posterior lip part is arranged at the rear end of the medial fossa, a lateral posterior lip part is arranged at the rear end of the lateral fossa, the upper end of the lateral posterior lip part has a section area, the outside of the section area is not higher than the inside of the section area, and the front end of the section area is not higher than the rear end of the section area.

[0008] The tibial pad according to an embodiment of the present application, since the outside of the section area of the upper end of the lateral posterior lip part is not higher than the inside of the section area, and the front end of the section area is not higher than the rear end of the section area, the blocking effect of the lateral posterior lip part on the femoral prosthesis is small, the femoral prosthesis can achieve a large external rotation angle, and the tibial pad of an embodiment of the present application can reduce the interface stress of the bone cement, so that the tibial pad has good use effect and high reliability.

[0009] In some embodiments, in a horizontal plane, the size between the front end of the section area and the rear end of the section area is L1, and the size between the front end of the tibial pad and the rear end of the tibial pad is LAP, wherein 0.2≤L1 / LAP≤0.4.

[0010] In some embodiments, a distance between an outer side of the section area and a median sagittal plane of the tibial liner is L2, the outer condyle is adapted to cooperate with a lateral condyle of a femoral prosthesis, a distance between a lowest point of the lateral condyle in a motion trajectory line in the outer condyle and the median sagittal plane of the tibial liner is L3, wherein 0.6≤L2 / L3≤0.9.

[0011] In some embodiments, a height of the lateral posterior lip is not higher than a height of the medial posterior lip.

[0012] In some embodiments, a height difference between a highest point of the section area and a lowest point of the lateral condyle is H1, wherein 0≤H1≤3mm.

[0013] In some embodiments, a surface where the section area is located is a curved surface, and a peripheral contour of the section area is substantially a sector.

[0014] In some embodiments, the tibial liner is a PS type tibial liner or a CR type tibial liner.

[0015] A knee prosthesis according to another embodiment of the present application, comprising: a femoral prosthesis, the femoral prosthesis comprising a medial condyle and a lateral condyle; a tibial liner, the tibial liner being the tibial liner according to any one of the above embodiments, the medial condyle cooperating with the medial condyle, and the lateral condyle cooperating with the lateral condyle.

[0016] The lateral posterior lip of the tibial liner according to the embodiments of the present application has a small blocking effect on the femoral prosthesis, so that the femoral prosthesis can reach a larger external rotation angle, and the knee prosthesis according to the embodiments of the present application can reduce the interface stress of the bone cement, so that the tibial liner has a better use effect and higher reliability, and the risk of loosening of the knee prosthesis is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a top view of the tibial liner according to an embodiment of the present application.

[0018] Figure 2 is a side view of the tibial liner according to an embodiment of the present application.

[0019] Figure 3 is a side view of the tibial liner according to another embodiment of the present application.

[0020] Figure 4 is a sectional view of the knee prosthesis according to an embodiment of the present application.

[0021] Figure 5 is a schematic view of the tibial liner according to an embodiment of the present application without a section area.

[0022] Figure 6Fig. 4 is a schematic view of a tibial insert according to an embodiment of the present application.

[0023] Figure 7 Fig. 5 is a comparison view of the external rotation angle of a knee prosthesis according to an embodiment of the present application and an original knee joint.

[0024] Figure 8 Fig. 6 is a comparison view of the external rotation angle of a knee prosthesis according to another embodiment of the present application and an original knee joint.

[0025] Reference numerals:

[0026] 1. tibial insert; 11, medial fossa; 111, medial posterior lip; 12, lateral fossa; 121, lateral posterior lip; 1211, section area;

[0027] 2. femoral prosthesis; 21, medial condyle; 22, lateral condyle. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below are exemplary and are intended to explain the present application, and should not be understood as limiting the present application.

[0029] In order to better explain and illustrate the technical solutions of the present application, the directions and the like involved in the present application are explained and illustrated in combination with the conventional description methods in the field.

[0030] In the field of anatomy and medical devices, the directions and planes such as medial, lateral, anterior, posterior, distal, proximal, sagittal plane, coronal plane, transverse plane have specific meanings, and are well known to those skilled in the art, and if not specifically stated, these terms refer to the meanings recognized by those skilled in the art.

[0031] Generally, when describing a human body, a joint or a prosthesis, the following three sections are usually involved: sagittal plane, coronal plane and transverse plane. Among them, the sagittal plane refers to a longitudinal section that divides the human body or joint into left and right parts from front to back, and the sagittal plane that passes through the center of the human body is the median sagittal plane, which divides the human body into two equal parts. The coronal plane refers to a longitudinal section that divides the human body or joint into front and back parts from left to right, and the coronal plane is perpendicular to the sagittal plane. The transverse plane is a plane that divides the human body or joint into upper and lower parts parallel to the ground plane, and the transverse plane is perpendicular to the coronal plane and the sagittal plane.

[0032] It can be understood that when describing a knee joint or a knee joint prosthesis, the sagittal plane, the coronal plane and the transverse plane all refer to the section when the human body is normally upright, at this time the flexion angle of the knee joint is 0°. When the knee joint or the knee joint prosthesis is flexed or the posture of the human body is adjusted, the section can change accordingly.

[0033] Typically, when describing the human body, joints, or prostheses, three different directions are involved: distal, medial, and posterior. The distal end refers to the end of the body or joint relatively far from the trunk. The proximal end refers to the end of the body or joint relatively close to the trunk. The medial end refers to the side relatively close to the midsagittal plane of the body. The lateral end refers to the side relatively far from the midsagittal plane of the body. The anterior end refers to the end relatively close to the abdomen in the sagittal plane. The posterior end refers to the end relatively close to the back in the sagittal plane.

[0034] The following is a reference appendix. Figures 1 to 8 A tibial liner and a knee joint prosthesis according to embodiments of the present invention are described.

[0035] like Figures 1 to 4 As shown, the tibial liner 1 of this embodiment includes a medial fossa 11 and a lateral fossa 12. The posterior end of the medial fossa 11 is provided with a medial posterior lip 111, and the posterior end of the lateral fossa 12 is provided with a lateral posterior lip 121. The upper end of the lateral posterior lip 121 has a cross-sectional area 1211. The lateral side of the cross-sectional area 1211 is not higher than the medial side of the cross-sectional area 1211, and the anterior end of the cross-sectional area 1211 is not higher than the posterior end of the cross-sectional area 1211. It can be understood that the medial fossa 11 and the lateral fossa 12 of the tibial liner 1 are adapted to cooperate with the medial condyle 21 and the lateral condyle 22 of the femoral prosthesis 2, and the femoral prosthesis 2 can swing back and forth or rotate relative to the tibial liner 1.

[0036] If the prosthesis between the femur and tibia is restricted in rotation during a deep squat, it will prevent the patient from regaining a natural knee feel and will also increase the stress at the bone cement interface, thus increasing the risk of prosthesis loosening. Clinical studies have found that prosthesis loosening is the most common cause of knee joint failure in total knee replacement surgery, accounting for 25%-40% of failure cases.

[0037] In the embodiment of the present invention, the tibial liner 1 has a cross-sectional area 1211 at the upper end of the lateral posterior lip 121, which reduces the height of the lateral posterior lip 121. In other words, the tibial liner 1 of the embodiment of the present invention optimizes the external rotation angle of the femoral prosthesis 2 by setting the cross-sectional area 1211. Therefore, while ensuring that the femoral prosthesis 2 does not dislocate, the knee joint prosthesis can achieve a larger femoral external rotation angle during high flexion, thereby reducing the interfacial stress of the bone cement, reducing the risk of prosthesis loosening, and improving prosthesis reliability. Therefore, the tibial liner 1 of the embodiment of the present invention has a reasonable structural design and good performance.

[0038] It is understandable that, such as Figure 1As shown, when the knee joint prosthesis performs internal axial movement with the medial condyle 11 as the axis, the movement trajectory of the lateral condyle 22 of the femoral prosthesis 2 on the lateral condyle 12 of the tibial pad 1 is approximately arc-shaped, and the arc-shaped trajectory is more obvious in the area closer to the posterior side of the tibial pad 1, so that the femoral prosthesis 2 mainly contacts the lateral posterior lip 121 of the tibial pad 1 at a larger external rotation angle. When the height of the lateral posterior lip 121 of the tibial pad 1 is reduced by setting the section area 1211, the blocking effect of the lateral posterior lip 121 of the tibial pad 1 on the femoral prosthesis 2 is reduced, thereby facilitating the femoral prosthesis 2 to reach a larger external rotation angle.

[0039] In addition, since the outer side of the section area 1211 is not higher than the inner side of the section area 1211, that is, the outer side of the section area 1211 is lower than or equal to the inner side of the section area 1211, and the front end of the section area 1211 is lower than or equal to the rear end of the section area 1211, the blocking effect of the lateral posterior lip 121 on the femoral prosthesis 2 is small, the femoral prosthesis 2 can reach a larger external rotation angle, and the tibial pad 1 of the embodiment of the present application can reduce the interface stress of the bone cement, so that the structure design of the tibial pad 1 is reasonable, the use effect is good, and the reliability is high. And the wrapping of the section area 1211 of the above structure on the femoral prosthesis 2 is better, and the risk of dislocation is not easy to occur.

[0040] In some embodiments, the height of the lateral posterior lip 121 is not higher than the height of the medial posterior lip 111. In other words, the height of the lateral posterior lip 121 is equal to or lower than the height of the medial posterior lip 111.

[0041] For example, the height of the lateral posterior lip 121 is equal to the height of the medial posterior lip 111, so that the tibial pad 1 of the embodiment of the present application can increase the external rotation angle of the femoral prosthesis at high flexion without changing the rotation stability of the femoral prosthesis at low flexion.

[0042] For another example, the height of the lateral posterior lip 121 is lower than the height of the medial posterior lip 111, so that the tibial pad 1 of the embodiment of the present application can increase the external rotation angle of the femoral prosthesis at high flexion more greatly while maintaining the low flexion stability of the knee joint during normal movement.

[0043] Specifically, as shown in the drawings, Figure 1 the surface where the section area 1211 is located is a curved surface, and the outer peripheral contour of the section area 1211 is generally fan-shaped, so that the processing and manufacturing of the section area 1211 can be facilitated, and the structure design of the lateral posterior lip 121 is more reasonable, thereby further improving the use effect of the tibial pad 1.

[0044] Optionally, as shown in the drawings, Figure 1As shown in the drawings, the size between the front end of the cross-sectional area 1211 and the rear end of the cross-sectional area 1211 in the horizontal plane is L1, and the size between the front end of the tibial pad 1 and the rear end of the tibial pad 1 is LAP, wherein 0.2≤L1 / LAP≤0.4. The inventors of the present application have found through experimental research that when the size L1 between the front end of the cross-sectional area 1211 and the rear end of the cross-sectional area 1211 and the size LAP between the front end of the tibial pad 1 and the rear end of the tibial pad 1 satisfy the above range, the blocking effect of the lateral posterior lip 121 on the femoral prosthesis 2 can be further reduced, the external rotation angle of the femoral prosthesis 2 can be increased under the condition that the femoral prosthesis 2 does not dislocate, and when L1 / LAP satisfies the above range, the interface stress of the bone cement filled between the prosthesis and the human joint is small, and the reliability is high.

[0045] For example, L1 / LAP can be 0.2, 0.3, 0.35, 0.4. The inventors of the present application have found through experimental research that when L1 / LAP is the above value, the external rotation angle of the femoral prosthesis 2 can be further increased, and the interface stress of the bone cement can be reduced.

[0046] Further, as shown in the drawings, Figure 1 the distance between the lateral side (the left end of the cross-sectional area 1211) of the cross-sectional area 1211 and the median sagittal plane of the tibial pad 1 is L2, the lateral fossa 12 is adapted to cooperate with the lateral condyle 22 of the femoral prosthesis 2, and the distance between the motion trajectory line of the lowest point of the lateral condyle 22 in the lateral fossa 12 and the median sagittal plane P of the tibial pad 1 is L3, wherein 0.6≤L2 / L3≤0.9. It can be understood that when the lateral condyle 22 swings back and forth in the lateral fossa 12, the lowest point of the lateral condyle 22 forms a motion trajectory line substantially parallel to the median sagittal plane in the lateral fossa 12, and the distance between the motion trajectory line and the median sagittal plane of the tibial pad 1 is L3.

[0047] The inventors of the present application have found through experimental research that when L2 / L3 satisfies the above range, the blocking effect of the lateral posterior lip 121 on the femoral prosthesis 2 can be further reduced, the external rotation angle of the femoral prosthesis 2 can be increased under the condition that the femoral prosthesis 2 does not dislocate, and when L2 / L3 satisfies the above range, the interface stress of the bone cement filled between the prosthesis and the human joint is small, and the reliability is high.

[0048] For example, L2 / L3 can be 0.6, 0.65, 0.7, 0.8, 0.9. The inventors of the present application have found through experimental research that when L2 / L3 is the above value, the external rotation angle of the femoral prosthesis 2 can be further increased, and the interface stress of the bone cement can be reduced.

[0049] Optionally, as shown in the drawings, Figure 1 and Figure 2As shown, the height difference between the highest point of the section area 1211 and the lowest point of the outer side socket 12 is H1, wherein 0≤H1≤3mm. For example, H1 can be 0, 1mm, 2mm, 3mm. The inventors of the present application have found through experimental research that when H1 satisfies the above range, the external rotation angle of the femoral prosthesis 2 can be further increased, the interfacial stress of the bone cement is reduced, and the structural design of the tibial pad 1 is more reasonable, and the use effect is better.

[0050] Specifically, as shown in Figure 2 and Figure 3 , the tibial pad 1 is a PS type tibial pad or a CR type tibial pad, for example, as shown in Figure 5 and Figure 6 , which are contrast diagrams of the PS type tibial pad before and after setting the section area 1211. As shown in Figure 1 , it is a top view of the CR type tibial pad with the section area 1211.

[0051] Specifically, the inventors use the PS type tibial pad or the CR type tibial pad to conduct comparative experiments as follows.

[0052] As shown in Figure 7 , the inventors set the section area 1211 on the PS type tibial pad, and make two different forms of the section area 1211, namely Figure 7 Scheme 1 and Scheme 2, specifically, the prosthesis size of Scheme 1 and Scheme 2 is the same, and the value of L2 / L3 of the section area 1211 of Scheme 1 is smaller than that of Scheme 2. Then, Scheme 1, Scheme 2 and the original knee joint are compared for experiments, and the inventors of the present application have found that setting the section area 1211 with the above structure on the PS type tibial pad can make the knee joint prosthesis have a larger external rotation angle, and the use effect of the knee joint prosthesis is better.

[0053] As shown in Figure 8 , the inventors set the section area 1211 on the CR type tibial pad, and make two different forms of the section area 1211, namely Figure 8 Scheme 1 and Scheme 2, specifically, the prosthesis size of Scheme 1 and Scheme 2 is the same, and the value of L2 / L3 of the section area 1211 of Scheme 1 is smaller than that of Scheme 2. Then, Scheme 1, Scheme 2 and the original knee joint are compared for experiments, and the inventors of the present application have found that setting the section area 1211 with the above structure on the PS type tibial pad can make the knee joint prosthesis have a larger external rotation angle, and the use effect of the knee joint prosthesis is better.

[0054] Therefore, the inventor of the present application concludes that the tibial pad 1 can be a posterior stabilized tibial pad prosthesis or a posterior cruciate ligament replacement tibial pad prosthesis, and thus the present application does not limit the type of tibial pad.

[0055] As shown in FIG. 1, the knee joint prosthesis of another embodiment of the present application comprises a femoral prosthesis 2 and a tibial pad 1, the femoral prosthesis 2 comprises a medial condyle 21 and a lateral condyle 22, and the tibial pad 1 is the tibial pad 1 of the above-mentioned embodiment of the present application, the medial condyle 21 is matched with the medial fossa 11, and the lateral condyle 22 is matched with the lateral fossa 12. Figure 4 According to the tibial pad 1 of the knee joint prosthesis of the embodiment of the present application, the blocking effect of the lateral posterior lip portion 121 of the tibial pad 1 on the femoral prosthesis 2 is small, so that the femoral prosthesis 2 can achieve a larger external rotation angle, and the knee joint prosthesis of the embodiment of the present application can reduce the interface stress of the bone cement, so that the use effect of the tibial pad 1 is better, and the risk of loosening of the knee joint prosthesis is reduced, so that the reliability after implantation of the knee joint prosthesis is higher.

[0056] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0057] In addition, the terms "second" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "second" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0058]

[0059] ​In the present application, unless specifically defined otherwise, the terms "mount", "connected", "connecting", "fixed", "unfixed", and the like should be construed broadly and can include fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or communication connections between each other; direct connections, or indirect connections via an intermediate medium; or internal communication between two elements or interaction between two elements. The specific meanings of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

[0060] In the present application, unless specifically defined otherwise, the second feature "on", "above", or "over" the second feature can be direct contact between the second and the second feature, or indirect contact between the second and the second feature through an intermediate medium. Moreover, the second feature "on", "above", and "over" the second feature can be directly above or obliquely above the second feature, or simply indicate that the second feature is higher in horizontal height than the second feature. The second feature "under", "below", and "underneath" the second feature can be directly below or obliquely below the second feature, or simply indicate that the second feature is lower in horizontal height than the second feature.

[0061] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those of ordinary skill in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples, without contradiction.

[0062] Although embodiments of the present application have been shown and described above, it is to be understood that the above-described embodiments are exemplary, and are not to be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present application.

Claims

1. A tibial spacer, characterized in that, The medial side recess is provided with a medial side posterior lip at a posterior end thereof, and the lateral side recess is provided with a lateral side posterior lip at a posterior end thereof, the upper end of the lateral side posterior lip is provided with a section area, the outer side of the section area is not higher than the inner side of the section area, and the anterior end of the section area is not higher than the posterior end of the section area; In a horizontal plane, the size between the anterior end of the section area and the posterior end of the section area is L1, and the size between the anterior end of the tibial pad and the posterior end of the tibial pad is LAP, wherein 0.2≤L1 / LAP≤0.4; The distance between the outer side of the section area and the median sagittal plane of the tibial pad is L2, the lateral side recess is adapted to cooperate with the lateral condyle of the femoral prosthesis, the lowest point of the lateral condyle in the movement trajectory line in the lateral side recess is L3, and wherein 0.6≤L2 / L3≤0.

9.

2. The tibial bushing of claim 1, wherein, The height of the lateral side posterior lip is not higher than the height of the medial side posterior lip.

3. The tibial bushing of claim 1, wherein, The height difference between the highest point of the section area and the lowest point of the lateral side recess is H1, wherein 0≤H1≤3mm.

4. The tibial bushing of claim 1, wherein, The surface where the section area is located is a curved surface, and the outer peripheral contour of the section area is generally a sector.

5. The tibial spacer of any of claims 1-4, wherein, The tibial pad is a PS type tibial pad or a CR type tibial pad.

6. A knee prosthesis, characterized in that The femoral prosthesis comprises: A femoral prosthesis, comprising a medial condyle and a lateral condyle; A tibial pad, the tibial pad is the tibial pad according to any one of claims 1-5, the medial condyle cooperates with the medial side recess, and the lateral condyle cooperates with the lateral side recess.

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