ARTIFICIAL ANKLE JOINT TALUS COMPONENT
20200197187 ยท 2020-06-25
Inventors
Cpc classification
A61F2/42
HUMAN NECESSITIES
A61F2002/30878
HUMAN NECESSITIES
International classification
Abstract
The present disclosure relates to an artificial ankle joint talus component and, more particularly, to an artificial ankle joint talus component including a joint surface in contact with an insert and a contact surface in contact with a bone, wherein the contact surface may be formed to be complementary to a resected surface of a talus so as to cover the entire resected surface, thereby dispersing stress, and reducing after-effects of surgery, such as osteolysis, heterotopic ossification, or the like.
Claims
1. An implant that is implanted into a body, the implant comprising a contact surface having a shape complementary to a resected surface of a bone into which the implant is implanted so as to increase contact area with respect to the bone, thereby distributing stress and mitigating side effects after surgery.
2. The implant of claim 1, wherein the implant is a talus component coupled to a talus in artificial ankle joint arthroplasty, wherein the talus component comprises a joint surface in contact with an insert, and wherein the joint surface is formed to have a curvature in an anterior and posterior direction so as to enable a joint motion of an ankle.
3. The implant of claim 2, wherein the joint surface comprises a medial joint surface positioned at a medial side, a lateral joint surface positioned at a lateral side, and a connection joint surface for connecting the medial joint surface and the lateral joint surface.
4. The implant of claim 3, wherein a posterior boundary of the contact surface has a gentle arc shape, which is formed to be convex toward the posterior, and wherein the joint surface extends to the posterior boundary of the contact surface toward the posterior while having a curvature to maintain a large contact area with the talus, thereby distributing stress, mitigating side effects after surgery, and enabling a motion in a wide range.
5. The implant of claim 3, wherein an anterior boundary of the contact surface has a gentle arc shape, which is formed to be convex toward the anterior, and wherein the joint surface extends to the anterior boundary of the contact surface toward the anterior while having a curvature to maintain a large contact area with the talus, thereby distributing stress, mitigating side effects after surgery, and enabling a motion in a wide range.
6. The implant of claim 3, wherein a posterior boundary of the contact surface has a gentle arc shape, which is formed to be convex toward the posterior, wherein the joint surface extends to the posterior boundary of the contact surface toward the posterior while having a curvature, wherein an anterior boundary of the contact surface has a gentle arc shape, which is formed to be convex toward the anterior, and wherein the joint surface extends to the anterior boundary of the contact surface toward the anterior while having a curvature to maintain a large contact area with the talus, thereby distributing stress, mitigating side effects after surgery, and enabling a motion in a wide range.
7. The implant of claim 4, wherein tangents of a posterior medial boundary of the medial joint surface and a posterior lateral boundary of the lateral joint surface continuously extend toward the connection joint surface while having slopes opposite to each other and lead to each other.
8. The implant of claim 5, wherein tangents of an anterior medial boundary of the medial joint surface and an anterior lateral boundary of the lateral joint surface continuously extend toward the connection joint surface while having slopes opposite to each other and lead to each other.
9. The implant of claim 6, wherein tangents of a posterior medial boundary of the medial joint surface and a posterior lateral boundary of the lateral joint surface continuously extend toward the connection joint surface while having slopes opposite to each other and lead to each other, and wherein tangents of an anterior medial boundary of the medial joint surface and an anterior lateral boundary of the lateral joint surface continuously extend toward the connection joint surface while having slopes opposite to each other and lead to each other.
10. The implant of claim 7, wherein the slope of the tangent of each boundary approaches zero as it approaches the connection joint surface.
11. The implant of claim 2, wherein the talus component is formed in a truncated cone shape in which the width thereof increases as it goes from the posterior to the anterior thereof so as to have a shape complementary to the resected surface of the talus, thereby minimizing an amount of bone to be removed, increasing the contact area to distribute stress, and mitigating side effects after surgery.
12. The implant of claim 2, wherein the contact surface comprises an anterior surface inclined to one side in the anterior portion, an intermediate surface formed in a plane at the center thereof, and a posterior surface inclined to one side in the posterior portion, thereby minimizing an amount of bone to be removed.
13. The implant of claim 12, further comprising a peg extending from the intermediate surface to a distal end.
14. The implant of claim 13, wherein the peg extends to be inclined at a predetermined angle toward the posterior.
15. The implant of claim 14, wherein the peg is inclined at 60 to 70 degrees toward the posterior.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The above and other aspects, features, and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
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DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0075] Hereinafter, an artificial ankle joint talus component according to the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that the same components in the figures are represented by the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present disclosure will be omitted. Unless otherwise defined, all terms in this specification are equivalent to the general meanings of the terms understood by those of ordinary skill in the art to which the present disclosure pertains, and if the terms conflict with the meanings of the terms used herein, the definition is to be understood according to the present specification.
[0076] Now, an artificial ankle joint talus component of the present disclosure will be described in detail with reference to the accompanying drawings.
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[0078] Next, the position and anatomy of a talus will be described with reference to
[0079] (a) of
[0080] The talus body 911 is positioned in the upper portion of the talus 91, and has a talus fornix in the form of a side surface of a truncated cone. The talus fornix is in contact with the proximal end 931 of a tibia 93, and the tibia 93 moves forwards and backwards on the talus fornix, thereby performing dorsiflexion and plantar flexion motions. In general, in the case of artificial ankle joint arthroplasty, the upper portion of the talus fornix is resected in a certain range to form a cross-section corresponding to a talus component, and the talus component is inserted through the cross-section. Although the number of resected surfaces differs depending on products, a 3-surface tibia component for minimizing the amount of bone to be removed requires three resected surfaces, that is, an anterior resected surface, an intermediate resected surface, and a posterior resected surface. The anterior resected surface 9111 and the posterior resected surface 9115 are formed to be inclined forwards and backwards, respectively, along the bold line in (b) of FIG.3.
[0081] (c) of
[0082] Referring to the plan view of the talus fornix, the posterior boundary thereof is formed in a curve to be convex toward the posterior. Therefore, as will be described below, the posterior boundary 9115a of the posterior resected surface 9115, among the resected surfaces of the talus, is also formed to be curved toward the posterior. However, the talus component of an existing artificial ankle joint has a posterior boundary in the form of a recessed curve or a straight line, thereby failing to simulate the shape of the talus correctly.
[0083] In addition, the talus fornix has curved corners rather than right-angled corners. However, the talus component of the conventional artificial ankle joint is formed in a rectangle that does not conform to the shape of the resected surface of the talus.
[0084] Next, an artificial ankle joint system coupled to the talus component 1 to implement a joint motion of the ankle and a principle thereof will be briefly described with reference to
[0085] An insert 5 made of plastic or the like and serving as a bearing is positioned on the talus component 1, and the talus component 1 slides back and forth along the curvature of the lower surface of the insert 5 in response to motion of the ankle, thereby implementing joint motions corresponding to dorsiflexion and plantar flexion motions. A tibial component 3, which is coupled to a distal end 933 of the tibia 93 and supports the load of the tibia 93, is positioned on the insert 5. The tibial component 3 may be a fixed type in which the tibial component 3 is immovably fixed to the insert 5, may be a semi-fixed type in which the tibial component 3 and the insert 5 partially restrict each other to allow a limited relative motion therebetween, or may be a free type in which the tibial component 3 is capable of unrestricted movement.
[0086] A combination of two or three components described above performs a joint motion in place of the ankle.
[0087] Now, the present disclosure will be described with reference to
[0088] Referring to
[0089] Referring to
[0090] Referring to
[0091] The joint surface 111 may include a medial joint surface 1111 close to the central side of a human body and a lateral joint surface 1115 close to a lateral side thereof. A connection joint surface 1113 positioned between the medial joint surface 1111 and the lateral joint surface 1115 may be formed to be recessed lower than the two surfaces 1111 and 1115. This can be confirmed in more detail in
[0092] The portions of the medial and lateral joint surfaces 1111 and 1115 at the edges in the medial and lateral directions may be formed to have angled surfaces, respectively, or may be more preferably formed to have gentle curved surfaces. This is due to the fact that the above-described prior art provides an excellent effect of preventing luxation of the insert 5 by forming the medial and lateral boundaries of the joint surface 111 to have a predetermined height, but has a disadvantage in that once luxation occurs, self-recovery is impossible, so that a surgical method for recovery is required. However, in the case where the medial and lateral boundaries are formed to be curved, if subluxation of the insert 5 occurs, natural recovery is possible.
[0093] In addition, the joint surface 111 may be preferably formed to extend to the edges of the contact surface 113 at the above curvature in the anterior and posterior/medial and lateral directions. The edges of the contact surface 113 may be formed along the resected surfaces of the talus fornix. If the joint surface 111 also extends the above edges, it is possible to maximize the movable range of the insert 5 and to provide effective distribution of stress.
[0094] In addition, the joint surface 111 meets the contact surface 113 at the boundaries thereof, and boundaries 1131a, 1131b, 1133a, 1133b, 1135a, and 1135b of the contact surface 113, which will be described later, are shared by the joint surface 111. Thus, the boundaries of the contact surface 113 may be regarded as the boundaries of the joint surface 111, so that the boundaries will be used to indicate the boundaries of both in the specification including the claims. However, it is clearer to describe the boundaries on the basis of the contact surface 113, and thus the following description will be made based on the same.
[0095] The detailed shape of the contact surface 113 will be described with reference to
[0096] Referring to
[0097] Referring to
[0098] The anterior surface 1131 may include an anterior lateral boundary 1131a at the lateral side thereof and an anterior medial boundary 1131b at the medial side thereof. The two anterior boundaries 1131a and 1131b may have a gentle arc shape, which is formed to be convex toward the anterior, thereby forming the shape complementary to the resected surface of the talus fornix. This is due to the fact that the anterior portion 9111 of the resected surface of the talus converges at the anterior.
[0099] At this time, if it is assumed that an anterior surface boundary 1131c, which is a boundary between the intermediate surface 1133 and the anterior surface 1131, corresponds to a horizontal axis, that a line 113a perpendicular to the horizontal axis and included in the anterior surface 1131 corresponds to a vertical axis, that the positive direction of the vertical axis corresponds to the anterior direction, and that the positive direction of the horizontal axis corresponds to the medial direction, the tangents of the anterior medial boundary 1131a and the anterior lateral boundary 1131b may continuously extend to the connection joint surface 1113 while having slopes opposite to each other, thereby leading to each other. Further, the slope of the tangent of each boundary may approach zero as it approaches the connection joint surface. Thus, the structure may conform to the anatomical shape of the talus by configuring the anterior boundaries to be gently curved as described above.
[0100] Accordingly, the anterior portion of the talus component 1 including the contact surface 113 and the joint surface 111 extending to the boundary thereof has a shape complementary to the anterior portion 9111 of the resected surface of the talus 91. In this structure, the talus implant may maximally cover the resected surfaces of the bone, thereby preventing osteolysis. Further, the above structure may prevent heterotopic ossification, and may maximize the contact area to evenly distribute stress, thereby preventing load concentration and prolonging the lifespan of the artificial joint.
[0101] Referring to
[0102] At this time, if it is assumed that a posterior surface boundary 1135c, which is a boundary between the intermediate surface 1133 and the posterior surface 1135, corresponds to a horizontal axis, that a line 113a perpendicular to the horizontal axis and included in the posterior surface 1135 corresponds to a vertical axis, that the positive direction of the vertical axis corresponds to the anterior direction, and that the positive direction of the horizontal axis corresponds to the medial direction, tangents of the posterior medial boundary 1135a and the posterior lateral boundary 1135b may continuously extend to the connection joint surface 1113 while having slopes opposite to each other, thereby leading to each other. Further, the slope of the tangent of each boundary may approximate zero as it approaches the connection joint surface. Thus, the structure may conform to the anatomical shape of the talus by configuring the posterior boundaries to be gently curved as described above.
[0103] Accordingly, the posterior portion of the talus component 1 including the contact surface 113 and the joint surface 111 extending to the boundary thereof has the shape complementary to the posterior portion 9115 of the resected surface of the talus 91. In addition, the above structure may prevent heterotopic ossification, and may maximize the contact area to evenly distribute stress, thereby preventing load concentration and prolonging the lifespan of the artificial joint.
[0104] Referring to
[0105] The peg 13 is an element that deeply penetrates into the bone by passing through the resected surface of the talus 91 to securely fix the talus component 1 to the talus 91. The pegs 13 are provided in each medial/lateral side, thereby preventing rotation thereof in the process of insertion.
[0106] A lower end 133 of the peg 13 may be configured in the form of a hemisphere, or may be configured to be a pointed figure such as a triangular pyramid, a quadrangular pyramid, or the like. In addition, any configuration may be applied to the lower end of the peg so as to enable insertion and fixation.
[0107] Preferably, the pegs 13 are formed to extend from the intermediate surface 1133 of the contact surface 113 to one side.
[0108] In artificial ankle joint arthroplasty, after a process of resecting a bone and selecting a size through trial, holes are formed in the talus 91, and the pegs 13 are inserted into the holes, thereby fixing the talus component 1. At this time, the peg 13 is inserted into the hole to a predetermined depth, and then a step of impacting the peg using a hammer or the like is performed to insert the same deeply, thereby fixing the talus component 1. At this time, if the peg 13 is positioned in the intermediate surface 1133, it is possible to prevent the posterior portion of the talus component 1 from being lifted up from the talus 91 by the rotation of the talus component 1 about the peg 13 in the anterior and posterior direction when impacting the same for insertion.
[0109] Now, a configuration for preventing the posterior portion from being lifted as described above will be described with reference to
[0110] A shows a talus component, and B shows the present disclosure in which the peg 13 is positioned in the intermediate surface 1133.
[0111] Referring to
[0112] As in the present disclosure (B), if the peg 13 is located in the intermediate surface 1133, the distance (r2) from the peg 13, which is the center of momentum, to the end thereof is short. Therefore, even if momentum occurs, the posterior portion is not lifted up much, thereby ensuring a strong connection with the talus 91. Even if the momenta in both cases are the same because the distance d from the force acting point to the peg is the same as d, the degree of lifting of the posterior portion is different therebetween (S>S).
[0113] The peg 13 may be formed to extend at an incline from the intermediate surface 1133 of the contact surface 113 in the posterior direction. In artificial ankle joint arthroplasty, an anterior approach method is primarily performed by resecting the anterior portion of the ankle. In this case, since the ankle is thinner than other parts, the anterior incision is very narrow. Thus, it is necessary to push and fix the talus component 1 through a narrow space from the front. Accordingly, if the peg 13 is formed to be inclined from the anterior to the posterior, easier insertion and impacting are possible. At this time, the inclination angle of the peg 13 is preferably about 60 to 70 degrees with respect to the intermediate surface 1133.
[0114] According to the above-described configuration, the talus component 1 has the shape complementary to the resected surface obtained by cutting the body 911 of the talus 91, thereby securing a firm connection without exposure. In addition, it is possible to prevent heterotopic ossification, and thus osteoysis may be prevented. In addition, it is possible to prolong the lifespan of the implant by increasing the contact area to thus evenly distribute stress.
[0115] Referring to
[0116] Although the above description has been made on the basis only of the talus component used in the artificial ankle joint, the description may also be applied to a tibia component, and the present disclosure may also be applied to implants used in artificial knee joints, artificial hip joints, artificial shoulder joints, or the like.
[0117] The above detailed description illustrates an example of the present disclosure. In addition, the above description relates to a preferred embodiment of the present disclosure, and the present disclosure may be used in various other combinations, modifications, and environments. That is, the present disclosure may be changed or modified within the scope of the concept of the disclosure disclosed in the present specification, the scope equivalent to the disclosed content, and/or the scope or knowledge of the art. The above-described embodiment illustrates the best mode for carrying out the technical idea of the present disclosure, and various modifications required for a specific application field and usage of the present disclosure are possible. Therefore, the detailed description of the disclosure above is not intended to limit the present disclosure to the disclosed embodiment. Further, the appended claims must be construed to encompass other embodiments.