CN215606593U

CN215606593U - Tibia liner

Info

Publication number: CN215606593U
Application number: CN202120774776.4U
Authority: CN
Inventors: 孙延东; 史忠兵; 赵开宇; 钱昦倩
Original assignee: Suzhou Microport Orthorecon Co Ltd
Current assignee: Suzhou Microport Orthorecon Co Ltd
Priority date: 2021-04-15
Filing date: 2021-04-15
Publication date: 2022-01-25
Anticipated expiration: 2031-04-15

Abstract

The present invention relates to a tibial insert. The tibial gasket comprises a medial articular surface and a lateral articular surface; the cross section line formed by the intersection of the medial articular surface and the first sagittal plane comprises a first circular arc, a first straight line segment and a second circular arc which are sequentially connected, and the curvature radius of the first circular arc is greater than or equal to that of the second circular arc. A section line formed by the intersection of the lateral articular surface and the second sagittal plane comprises a fourth circular arc, a second straight line segment and a fifth circular arc which are connected in sequence; the curvature radius of the fourth arc is larger than or equal to that of the fifth arc, and the tibial gasket is good in stability.

Description

Tibia liner

Technical Field

The utility model relates to the technical field of medical instruments, in particular to a tibial gasket.

Background

With the improvement of surgical techniques and knee prostheses, total knee replacement surgery is becoming more mature. The total knee replacement is an effective treatment means for solving the advanced arthritis, and the total knee replacement achieves better treatment effect with the continuous improvement of prosthesis and the development of knee surgery technology, however, the traditional total knee replacement still has the problems of postoperative 'contradictory anterior movement' and unstable knee flexion, wherein the 'contradictory anterior movement' means that the femur moves forwards relative to the tibia from the backward movement in a normal state in the knee flexion process of a patient after the total knee replacement. The problems of stress increase of the patellofemoral joint surface, pain of the front side of the knee joint and the like can be caused by inconsistent forward movement and unstable knee joint flexion, so that the postoperative experience of a patient is poor, and postoperative pain of the patient is increased.

SUMMERY OF THE UTILITY MODEL

Therefore, a need exists for a tibial insert that addresses the problem of improving knee stability after total knee replacement.

The present application provides a tibial insert comprising:

a medial articular surface, a cross-sectional line formed by the intersection of the medial articular surface and the first sagittal plane comprising a first circular arc, a first straight line segment and a second circular arc connected in sequence, the radius of curvature of the first circular arc being greater than or equal to the radius of curvature of the second circular arc, and,

a cross-sectional line formed by the intersection of the lateral articular surface and the second sagittal plane comprises a fourth circular arc, a second straight-line segment and a fifth circular arc which are connected in sequence; the radius of curvature of the fourth circular arc is greater than or equal to the radius of curvature of the fifth circular arc.

The technical solution of the present application is further described below:

in one embodiment, a cross-sectional line formed by the intersection of the medial articular surface and the first coronal surface comprises a third circular arc having a radius of curvature equal to the radius of curvature of the first circular arc; and/or a cross-sectional line formed by the intersection of the lateral articular surface and the second coronal surface comprises a sixth arc; the radius of curvature of the sixth arc is equal to the radius of curvature of the fourth arc.

In one embodiment, the length of the first straight line segment ranges from 0.1mm to 3 mm; and/or the length of the second straight line segment ranges from 9mm to 14 mm.

In one embodiment, the distance from the medial edge to the lateral edge of the tibial insert is a first distance, the tibial insert having a central sagittal plane defining the medial and lateral articular planes;

the distance from the first straight line segment to the central sagittal plane is a second distance, and the ratio of the second distance to the first distance ranges from 0.25 to 0.35; and/or the distance from the second straight line segment to the central sagittal plane is a third distance, and the ratio of the third distance to the first distance is in the range of 0.25-0.35.

In one embodiment, the anterior edge of the medial articular surface is a fourth distance from the posterior edge; the distance from the midpoint of the first straight line segment to the posterior edge of the medial articular surface is a fifth distance, and the ratio of the fifth distance to the fourth distance ranges from 0.3 to 0.5; and/or the anterior edge of the lateral articular surface is a sixth distance from the posterior edge; the distance from the midpoint of the second straight line segment to the posterior edge of the lateral articular surface is a seventh distance, and the ratio of the seventh distance to the sixth distance ranges from 0.3 to 0.5.

In one embodiment, the perpendicular distance from the end point of the first arc at the anterior edge of the medial articular surface to the first straight segment is 6mm-13 mm; and/or the perpendicular distance from the end point of the second circular arc at the posterior edge of the medial articular surface to the first straight line segment is 0.2mm-4 mm.

In one embodiment, the perpendicular distance from the end point of the fourth arc at the anterior edge of the lateral articular surface to the second straight segment is 3mm to 7 mm; and/or the vertical distance from the endpoint of the fifth circular arc at the posterior edge of the lateral articular surface to the second straight line segment is 0.2mm-3 mm.

In one embodiment, the tibial insert further comprises a convex surface connecting the medial and lateral articular surfaces, a cross-sectional line formed by the convex surface and the third coronal surface comprises a seventh arc, a cross-sectional line formed by the medial and third coronal surfaces comprises an eighth arc, a cross-sectional line formed by the lateral articular surface intersecting the third coronal surface comprises a ninth arc, the seventh arc is tangent to the eighth arc, and the seventh arc is tangent to the ninth arc.

In one embodiment, the radius of curvature of the seventh circular arc ranges from 35mm to 50 mm.

In one embodiment, the medial articular surface has, in cross-section, a first weight-bearing midline comprising a third linear segment, a tenth circular arc, and a fourth linear segment connected in series; the tenth arc is tangent to the third straight line segment and the fourth straight line segment respectively.

In one embodiment, the medial edge of the tibial insert is a first distance to the lateral edge, the tibial insert has a central sagittal plane defining the medial and lateral articular surfaces, the medial articular surface is a fourth distance from the anterior edge to the posterior edge; the intersection point of the extension line of the third straight line segment and the extension line of the fourth straight line segment is a first intersection point,

the distance from the first intersection point to the posterior edge of the medial articular surface is an eighth distance, and the ratio of the eighth distance to the fourth distance ranges from 0.35 to 0.45; and/or the distance from the first intersection point to the central sagittal plane is a ninth distance, and the ratio of the ninth distance to the first distance is 0.25-0.3.

In one embodiment, the tibial insert has a central sagittal plane defining the medial and lateral articular surfaces, the fourth line being parallel to the central sagittal plane.

In one embodiment, the tibial insert has a central sagittal plane defining the medial and lateral articular surfaces, and the third linear segment has an angle in the range of 20 ° -25 ° with respect to the central sagittal plane.

In one embodiment, the lateral articular surface has, in cross-section, a second weight-bearing midline comprising a fifth linear segment and an eleventh arc connected in series; the eleventh arc is tangent to the fifth straight line segment.

In one embodiment, the tibial insert has a first distance from a medial edge to a lateral edge, the tibial insert has a central sagittal plane defining the medial and lateral articular surfaces, the lateral articular surface has a sixth distance from an anterior edge to a posterior edge; the tangent point of the eleventh arc and the fifth straight-line segment is a third tangent point;

the distance from the third tangent point to the posterior edge of the lateral articular surface is a tenth distance, and the ratio of the tenth distance to the sixth distance ranges from 0.35 to 0.45; and/or the distance from the third tangent point to the central sagittal plane is an eleventh distance, and the ratio of the eleventh distance to the first distance is 0.25-0.3.

In one embodiment, the eleventh arc has a radius of curvature in a range of 35mm to 50 mm.

In one embodiment, the tibial insert has a central sagittal plane defining the medial and lateral articular surfaces, and the fifth linear segment has an angle with the central sagittal plane in the range of 10 ° -12 °.

The tibia liner improves the rotational stability of the knee joint prosthesis by designing the inner side joint surface and the outer side joint surface to be spherical-socket-shaped. In addition, the intersection lines of the inner side joint surface and the outer side joint surface and the sagittal plane are designed in a straight line, so that the installation and containment degree of the knee joint prosthesis in the operation is increased.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view of a tibial insert according to one embodiment;

FIG. 2 is a first top view of a tibial insert according to an embodiment;

FIG. 3 is a cross-sectional view of the tibial insert shown in FIG. 2 at section A-A;

FIG. 4 is a cross-sectional view of the tibial insert shown in FIG. 2 at section B-B;

FIG. 5 is a second top view of the tibial insert of an embodiment;

FIG. 6 is a cross-sectional view of the tibial insert shown in FIG. 5 taken at section D-D;

FIG. 7 is a cross-sectional view of the tibial insert illustrated in FIG. 5 at section C-C;

FIG. 8 is a third top view of a tibial insert of an embodiment;

FIG. 9 is a cross-sectional view of the tibial insert illustrated in FIG. 8 at section E-E;

FIG. 10 is a fourth top view of a tibial insert of an embodiment;

FIG. 11 is a schematic structural view of an exemplary femoral condyle prosthesis.

Description of reference numerals:

10. a tibial insert; 11. a medial articular surface; l111, first distance; l112, second distance; l113, fourth distance; l114, fifth distance; l115, a first straight line segment; l116, eighth distance; l117, ninth distance; r111, a first arc; r112, a second circular arc; r113, third arc; r114, tenth arc; 12. a lateral articular surface; l122, third distance; l123, sixth distance; l124, seventh distance; l125, a second straight line segment; l127, eleventh distance; l128, tenth distance; r121, a fourth arc; r122, a fifth arc; r123, a sixth arc; r124, eleventh arc; 13. a central sagittal plane; 14. a convex surface; r141, seventh arc; 20. a tibial condyle prosthesis; 21. an AP line; 22. the medial condylar articular surface; 23. the lateral condylar articular surface.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

To better explain the technical solutions of the present invention, the terms of orientation in the embodiments are explained first.

Sagittal plane: longitudinally cutting a human body or a joint into a section formed by a left part and a right part;

coronal plane: dividing the human body or the joint into a front section and a rear section, wherein the section is vertical to the sagittal plane;

cross section: dividing the human body or the joint into an upper section and a lower section, wherein the section is vertical to the coronal plane and the sagittal plane;

a far end: the end of the body or joint relatively far from the head;

proximal end: the human body or joint is relatively close to one end of the head;

inner side: relatively close to the sagittal plane of a human body;

outside: relatively deviated from the sagittal plane of the human body;

front side: the side near the chest in the sagittal plane;

rear side: the side of the sagittal plane near the back;

AP direction: a direction from anterior to posterior in the sagittal plane;

PA direction: a direction from posterior to anterior in the sagittal plane;

ML direction: a medial to lateral direction on the crown;

LM direction: in the lateral to medial direction on the coronal plane.

Specifically, referring to fig. 1, an embodiment of the present application provides a tibial insert 10, the tibial insert 10 being for fixation to the proximal end of a tibia that has been resected or to a tibial tray prosthesis. Further, the tibial insert 10 is divided into a left leg tibial insert 10 for the left leg and a right leg tibial insert 10 for the right leg. Wherein the left leg tibial insert 10 and the right leg tibial insert 10 are mirror images about the sagittal plane. In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, a left leg tibia pad 10 applied to a left leg will be described in detail below as an example. Specifically, tibial insert 10 of one embodiment includes a medial articular surface 11 and a lateral articular surface 12. Wherein the medial articular surface 11 is used to replace the medial tibial meniscus and the lateral articular surface 12 is used to replace the lateral tibial meniscus.

2-4, the cross-sectional line formed by the intersection of the medial articular surface 11 with the first sagittal plane includes a first circular arc R111, a first straight line segment L115, and a second circular arc R112 connected in series from anterior to posterior. The radius of curvature of the first circular arc R111 is greater than or equal to the radius of curvature of the second circular arc R112, and preferably, the radius of curvature of the first circular arc R111 is equal to the radius of curvature of the second circular arc R112. Further, the section line formed by the intersection of the medial articular surface 11 with the first coronal surface includes a third circular arc R113, and the radius of curvature of the third circular arc R113 is equal to the radius of curvature of the first circular arc R111.

In the tibial gasket 10, the intersection line of the medial articular surface 11 and the first sagittal plane is configured as the first arc R111, the first straight line segment L115 and the second arc R112 which are sequentially connected, the intersection line of the medial articular surface 11 and the first coronal plane is configured as the third arc R113, the radius of curvature of the first arc R111 is greater than or equal to the radius of curvature of the second arc R112, and the radius of curvature of the third arc R113 is equal to the radius of curvature of the first arc R111, so that the medial articular surface 11 is ensured to form a spherical socket shape, and the rotational stability of the knee joint prosthesis is further improved. In addition, the design that the intersection line of the medial articular surface 11 and the sagittal plane part adopts the first straight line segment L115 increases the installation tolerance of the knee joint prosthesis in the operation.

Specifically, the first sagittal plane is section A-A taken along line A-A in FIG. 2, with the cut location of section A-A corresponding to the extent of the path of contact during mating of medial articular surface 11 with the femoral condyle. Specifically, tibial insert 10 has a central sagittal plane 13 defining medial articular surface 11 and lateral articular surface 12, where central sagittal plane 13 refers to the sagittal plane passing through the medial and lateral centerlines of tibial insert 10, and the medial and lateral centerlines of tibial insert 10 refer to a line bisecting tibial insert 10 into medial and lateral portions, where "bisecting" refers to bisecting the lateral length of tibial insert 10. The distance from the medial edge to the lateral edge of the tibial insert 10 is designated as a first distance L111, and the distance from the first sagittal plane to the central sagittal plane 13 of the tibial insert 10 (i.e., the distance from the first straight line segment L115 to the central sagittal plane 13) is designated as a second distance L112. The ratio of the second distance L112 to the first distance L111 ranges from 0.25 to 0.35.

With continued reference to FIG. 2, the first coronal plane is section B-B, preferably passing through midpoint a of first straight line segment L115. Specifically, the anterior edge to the posterior edge of the medial articular surface 11 is a fourth distance L113; the distance from the midpoint a of the first straight line segment L115 to the posterior edge of the medial articular surface 11 (i.e., the distance from the first coronal surface to the posterior edge of the medial articular surface 11) is a fifth distance L114, and the ratio of the fifth distance L114 to the fourth distance L113 is in the range of 0.3-0.5, preferably 0.35-0.45.

The midpoint a of the first straight line segment L115 is the central position of the inner bearing area of the natural knee joint straightening position, and the midpoint position of the first straight line segment L115 is defined by the ratio range of the second distance L112 to the first distance L111 and the ratio range of the fifth distance L114 to the fourth distance L113, so that the contact position of the femur component at the straightening position and the tibia pad 10 prosthesis is defined, and the over-loosening and over-tightening of the knee joint straightening and flexion gap after the operation is avoided.

Further, the length of the first straight line segment L115 ranges from 0.1mm to 3mm, preferably from 0.5mm to 1.5 mm. The design can improve the installation and the accommodation degree of the inner joint surface 11 in the knee joint operation and provide a natural knee joint moving area.

Referring to fig. 3, the perpendicular distance H111 from the endpoint of the anterior edge of the medial articular surface 11 (i.e., the intersection of the anterior edge and the first sagittal plane) to the first straight line segment L115 (i.e., the anterior lip height of the medial articular surface 11) of the first circular arc R111 is 6mm to 13mm, preferably 8mm to 12mm, so as to ensure the stability of the medial articular surface 11 in the PA direction and avoid the impact of the patella with the anterior edge of the tibial insert 10 during high flexion of the knee joint. And/or, the perpendicular distance H112 from the end point of the posterior edge of medial articular surface 11 (i.e., the intersection of the posterior edge with the first sagittal plane) to first straight line segment L115 (i.e., the posterior lip height of medial articular surface 11) of second circular arc R112 is 0.2mm to 4mm, preferably 0.5mm to 3mm, thereby ensuring the stability of medial articular surface 11 in the AP direction and solving the problem of difficulty in implanting tibial insert 10 into the human body during knee replacement.

5-7, the cross-sectional line drawn by the intersection of the lateral articular surface 12 with the second sagittal plane includes a fourth circular arc R121, a second straight segment L125, and a fifth circular arc R122 connected in series from anterior to posterior. The radius of curvature of the fourth circular arc R121 is greater than or equal to the radius of curvature of the fifth circular arc R122, and preferably, the radius of curvature of the fourth circular arc R121 is equal to the radius of curvature of the fifth circular arc R122. Further, a cross-sectional line intersecting the lateral articular surface 12 and the second coronal surface includes a sixth circular arc R123, the radius of curvature of the sixth circular arc R123 being equal to the radius of curvature of the fourth circular arc R121.

In the tibial gasket 10, the intersection line of the lateral articular surface 12 and the second sagittal plane is configured as the fourth arc R121, the second straight line segment L125 and the fifth arc R122 which are connected in sequence, the intersection line of the lateral articular surface 12 and the second coronal plane is configured as the sixth arc R123, the radius of curvature of the fourth arc R121 is greater than or equal to the radius of curvature of the fifth arc R122, and the radius of curvature of the sixth arc R123 is equal to the radius of curvature of the fourth arc R121, so that the lateral articular surface 12 is ensured to form a spherical socket shape, and the rotational stability of the knee joint prosthesis is further improved. In addition, the design of the second straight line segment L125 is adopted for the intersection line of the lateral articular surface 12 and the sagittal plane part, so that the installation and the installation tolerance of the knee joint prosthesis in the operation are increased.

Specifically, the second sagittal plane is section D-D of FIG. 5, which is cut at a location corresponding to the extent of the path of contact during mating of the lateral articular surface 12 with the femoral condyle. Specifically, the distance from the second sagittal plane to the central sagittal plane 13 of the tibial insert 10 (i.e., the distance from the second straight line segment L125 to the central sagittal plane 13) is identified as the third distance L122. The ratio of the third distance L122 to the first distance L111 ranges from 0.25 to 0.35.

With continued reference to FIG. 5, the second coronal plane is section C-C, and preferably passes through midpoint b of the second straight line segment L125. Specifically, the anterior edge to the posterior edge of the lateral articular surface 12 is a sixth distance L123; the distance from the midpoint b of the second straight line segment L125 to the posterior edge of the lateral articular surface 12 (i.e., the distance from the second coronal surface to the posterior edge of the lateral articular surface 12) is a seventh distance L124, and the ratio of the seventh distance L124 to the sixth distance L123 is in the range of 0.3-0.5, preferably 0.35-0.45. Preferably, the second coronal plane coincides with the first coronal plane.

The midpoint b of the second straight line segment L125 is the central position of the inner bearing area of the natural knee joint straightening position, and the position of the midpoint b of the second straight line segment L125 is defined by the ratio range of the third distance L122 to the first distance L111 and the ratio range of the seventh distance L124 to the sixth distance L123, so that the contact position of the femur component at the straightening position and the tibia pad 10 prosthesis is defined, and the over-loosening and over-tightening of the knee joint straightening and flexion gaps after the operation are avoided.

Further, the length of the second straight line segment L125 ranges from 9mm to 14mm, preferably from 10mm to 12 mm. Such a design can improve the packaging tolerance of the lateral articular surface 12 during knee surgery and provide a natural knee articulation zone.

Referring to fig. 6, the perpendicular distance H121 from the end point of the anterior edge of the lateral articular surface 12 (i.e., the intersection of the anterior edge with the second sagittal plane) to the second straight line segment L125 (i.e., the anterior lip height of the lateral articular surface 12) is 3mm to 7mm, preferably 4mm to 6mm, so as to ensure the stability of the lateral articular surface 12 in the PA direction and avoid the impact of the patella with the anterior edge of the tibial insert 10 during high flexion of the knee joint. And/or the perpendicular distance H122 from the end point of the posterior edge of the lateral articular surface 12 (i.e., the intersection of the posterior edge with the second sagittal plane) to the second straight line segment L125 (i.e., the posterior lip height of the lateral articular surface 12) is 0.2mm to 3mm, preferably 0.5mm to 2.5mm, thereby ensuring the stability of the lateral articular surface 12 in the AP direction and solving the problem that the tibial insert 10 is difficult to implant in the human body during knee replacement.

Referring to fig. 8-9, the tibial insert 10 further includes a convex surface 14 connecting the medial articular surface 11 and the lateral articular surface 12, a cross-sectional line formed by the convex surface 14 and the third coronal surface includes a seventh arc R141, a cross-sectional line formed by the medial articular surface 11 and the third coronal surface includes an eighth arc, a cross-sectional line formed by the intersection of the lateral articular surface 12 and the third coronal surface includes a ninth arc, the seventh arc R141 is tangent to the eighth arc, and the seventh arc R141 is tangent to the ninth arc. Preferably, referring to fig. 9, the third coronal plane coincides with the second coronal plane and the first coronal plane, where the eighth arc is a third arc R113 and the ninth arc is a sixth arc R123.

Further, the curvature radius of the seventh circular arc R141 ranges from 35mm to 50 mm. If the radius of curvature of the seventh circular arc R141 is too large, the stability of the tibial insert 10 in the ML direction and the LM direction is poor, and if the radius of curvature of the seventh circular arc R141 is too small, the tibial insert 10 is difficult to implant into the human body. The curvature radius of the seventh circular arc R141 is set to be 35mm-50mm, so that the stability of the tibial gasket 10 in the ML direction and the LM direction is guaranteed, and a doctor can conveniently implant the tibial gasket 10 into a human body.

Further, natural knee joint motion exists with rotational motion centered on the medial meniscus and the medial femoral condyle midline is not parallel to the AP line 21, nor is the lateral femoral condyle midline parallel to the AP line 21. Therefore, the medial and lateral

articular surfaces

11 and 12 of the tibial insert 10 need to be designed not only to guide the rotation of the femoral condyles, but also to have a wobble design of the tibial insert 10 at the anterior end of the articular surface, so as to provide better matching and contact area between the articular surfaces of the tibial insert 10 in the straightened and hyperextended positions.

Referring to fig. 10, the medial articular surface 11 has a first weight-bearing midline in transverse cross-section. Specifically, the first weight-bearing midline refers to the set of points at which the femoral condyle prosthesis contacts the medial articular surface 11 of the tibial insert 10 during flexion, i.e., the trajectory along which the femoral condyle prosthesis moves on the medial articular surface 11 of the tibial insert 10 during knee flexion. Further, the point on the first weight-bearing midline is the most concave (nadir) point of the medial articular surface 11 on the coronal plane. Specifically, in the present embodiment, the first load-bearing center line includes a third straight line segment FM, a tenth arc R114 and a fourth straight line segment NG connected in sequence. The tenth arc R114 is tangent to the third straight line segment FM and the fourth straight line segment NG, respectively.

Further, the intersection of the extension of the third straight line segment FM and the extension of the fourth straight line segment NG is a first intersection P, the distance from the first intersection P to the posterior edge of the medial articular surface 11 is an eighth distance L116, the ratio of the eighth distance L116 to the fourth distance L113 is in the range of 0.35-0.45, and/or the distance from the first intersection P to the central sagittal plane 13 is denoted as a ninth distance L117, and the ratio of the ninth distance L117 to the first distance L111 is in the range of 0.25-0.3.

Further, the fourth straight line segment NG is parallel to the central sagittal plane 13. Furthermore, the included angle α 111 between the third straight line segment FM and the central sagittal plane 13 is in the range of 20 ° to 25 °, which enables the femoral condyle prosthesis and the tibial insert 10 to obtain better assembly and contact area during the process from hyperextension to extension, enables the tibial insert 10 to be stressed uniformly, and prolongs the service life of the tibia.

Referring to fig. 10, the lateral articular surface 12 has a second weight-bearing midline in cross section, which, for the same reason, refers to the collection of points at which the femoral condyle prosthesis contacts the lateral articular surface 12 of the tibial insert 10 during flexion, i.e., the trajectory along which the femoral condyle prosthesis moves on the lateral articular surface 12 of the tibial insert 10 during knee flexion. Further, the point on the first weight-bearing midline is the most concave (nadir) point of the medial articular surface 11 on the coronal plane. Specifically, in the present embodiment, the second load-bearing central line includes a fifth straight line segment CD and an eleventh arc R124 connected in sequence, and the eleventh arc R124 is tangent to the fifth straight line segment CD.

Further, a tangent point of the eleventh arc R124 and the fifth straight line segment CD is denoted as a third tangent point D, a distance from the third tangent point D to the posterior edge of the lateral articular surface 12 is a tenth distance L128, and a ratio of the tenth distance L128 to the sixth distance L123 is in a range of 0.35-0.45. And/or the third tangent point D is a eleventh distance L127 from the midsagittal plane 13, the ratio of the eleventh distance L127 to the first distance L111 being 0.25-0.3. Furthermore, the curvature radius of the eleventh arc R124 ranges from 35mm to 50mm, and the included angle alpha 121 between the fifth straight line segment CD and the central sagittal plane 13 ranges from 10 degrees to 12 degrees, so that the femoral condyle prosthesis and the tibial gasket 10 can obtain better assembly and contact area in the process of extending to straightening, the tibial gasket 10 is uniformly stressed, and the service life of the tibia is prolonged.

Further, to illustrate in more detail the design of the tibial insert 10 with a yaw at the anterior end that improves the fit and contact area of the knee prosthesis in the straightened and hyperextended positions, a femoral condyle prosthesis is introduced. Femoral condylar prostheses are used to secure to the surgically prepared distal femur in order to replace the articular surfaces of the distal femur. Referring to fig. 11, the femoral condyle prosthesis comprises a medial condyle articular surface 22 and a lateral condyle articular surface 23. The medial condyle articular surface 22 has a spherical radius SR22, and the spherical radius SR22 has a value 0.5mm to 1mm smaller than the radius of curvature of the third circular arc R113. The lateral condylar articular surface 23 has a spherical radius SR23, and the spherical radius SR23 is smaller than the radius of curvature of the sixth circular arc R123 by 0.5mm to 1 mm. The medial condyle articular surface 22 has a yaw at the anterior end of α 22, and α 22 has a value equal to α 111. The lateral condylar articular surface 23 has a yaw α 23 at the anterior end, and α 23 has a value equal to α 121. As used herein, "yaw" means the angle between the medial bearing line of the anterior end of the femoral condyle or the medial bearing line of the tibial insert 10 prosthesis and the sagittal plane.

Through the design of the included angle between the third straight line segment and the central sagittal plane 13 and the included angle between the fifth straight line segment CD and the central sagittal plane 13, the femoral condyle prosthesis and the tibial gasket 10 can obtain good assembly and contact area in the process of extending to straightening, so that the tibial gasket 10 is stressed uniformly, and the service life of the tibial gasket 10 is prolonged.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the utility model. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the utility model and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the utility model.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Claims

1. A tibial insert, comprising:

2. The tibial insert of claim 1, wherein said first linear segment has a length in the range of 0.1mm to 3 mm; and/or the length of the second straight line segment ranges from 9mm to 14 mm.

3. The tibial insert of claim 1, wherein the distance from the medial edge to the lateral edge of said tibial insert is a first distance, said tibial insert having a central sagittal plane defining said medial and lateral articular planes;

4. The tibial insert of claim 1, wherein the distance from the anterior edge to the posterior edge of said medial articular surface is a fourth distance; the distance from the midpoint of the first straight line segment to the posterior edge of the medial articular surface is a fifth distance, and the ratio of the fifth distance to the fourth distance ranges from 0.3 to 0.5; and/or the anterior edge of the lateral articular surface is a sixth distance from the posterior edge; the distance from the midpoint of the second straight line segment to the posterior edge of the lateral articular surface is a seventh distance, and the ratio of the seventh distance to the sixth distance ranges from 0.3 to 0.5.

5. The tibial insert of claim 1, wherein the perpendicular distance from the end point of said first arc at the anterior edge of said medial articular surface to said first straight line segment is 6mm-13 mm; and/or the perpendicular distance from the end point of the second circular arc at the posterior edge of the medial articular surface to the first straight line segment is 0.2mm-4 mm.

6. The tibial insert of claim 1, wherein the perpendicular distance from the end point of said fourth arc at the anterior edge of said lateral articular surface to said second linear segment is 3mm-7 mm; and/or the vertical distance from the endpoint of the fifth circular arc at the posterior edge of the lateral articular surface to the second straight line segment is 0.2mm-3 mm.

7. The tibial insert of claim 1, further comprising a convex surface connecting said medial and lateral articular surfaces, a cross-sectional line formed by said convex surface and a third coronal surface comprising a seventh arc, a cross-sectional line formed by said medial and third coronal surfaces comprising an eighth arc, a cross-sectional line formed by said lateral articular surface intersecting said third coronal surface comprising a ninth arc, said seventh arc being tangent to said eighth arc, and said seventh arc being tangent to said ninth arc.

8. The tibial insert of claim 7, wherein said seventh circular arc has a radius of curvature in the range of 35mm to 50 mm.

9. The tibial insert of claim 1, wherein said medial articular surface has, in transverse cross section, a first weight-bearing midline comprising a third linear segment, a tenth circular arc, and a fourth linear segment connected in series; the tenth arc is tangent to the third straight line segment and the fourth straight line segment respectively.

10. The tibial insert of claim 9, wherein said medial edge of said tibial insert is a first distance from a lateral edge, said tibial insert having a central sagittal plane defining said medial and lateral articular surfaces, said medial articular surface being a fourth distance from an anterior edge to a posterior edge; the intersection point of the extension line of the third straight line segment and the extension line of the fourth straight line segment is a first intersection point,

11. The tibial insert of claim 9, wherein said tibial insert has a central sagittal plane defining said medial and lateral articular surfaces, said fourth linear segment being parallel to said central sagittal plane.

12. The tibial insert of claim 9, wherein said tibial insert has a central sagittal plane defining said medial and lateral articular surfaces, said third linear segment being angled from said central sagittal plane by an angle in the range of 20 ° -25 °.

13. The tibial insert of claim 1, wherein said lateral articular surface has, in transverse cross section, a second weight-bearing midline comprising a fifth straight segment and an eleventh arc connected in series; the eleventh arc is tangent to the fifth straight line segment.

14. The tibial insert of claim 13, wherein said medial edge of said tibial insert is a first distance from a lateral edge, said tibial insert having a central sagittal plane defining said medial and lateral articular surfaces, said lateral articular surface being a sixth distance from an anterior edge to a posterior edge; the tangent point of the eleventh arc and the fifth straight-line segment is a third tangent point;

15. The tibial insert of claim 13, wherein said eleventh arc has a radius of curvature in the range of 35mm to 50 mm.

16. The tibial insert of claim 13, wherein said tibial insert has a central sagittal plane defining said medial and lateral articular surfaces, said fifth linear segment having an angle in the range of 10 ° -12 ° with respect to said central sagittal plane.

17. The tibial insert of claim 1, wherein:

a section line formed by the intersection of the medial articular surface and the first coronal surface comprises a third arc having a radius of curvature equal to the radius of curvature of the first arc; and/or the presence of a gas in the gas,

a cross-sectional line formed by the intersection of the lateral articular surface and the second coronal surface includes a sixth arc; the radius of curvature of the sixth arc is equal to the radius of curvature of the fourth arc.