JP7285510B2 - Artificial acetabulum component and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an artificial acetabulum component suitably used in total hip arthroplasty and a method for manufacturing the same.

Artificial hip replacement surgery is a surgery to improve walking ability and hip joint pain by replacing a hip joint deformed due to hip osteoarthritis, rheumatoid arthritis, femoral head necrosis, fracture, etc. with an artificial hip joint. The replacement method differs depending on the location and degree of deformation. For example, artificial hip joint replacement surgery for deformation or destruction of the acetabulum and femoral head is called total hip arthroplasty.

In a total hip arthroplasty (hereinafter sometimes referred to as THA), as shown in FIG. 10, a stem 52 and a femoral head ball 54 on the side of the femur, a cup 56 on the side of the acetabulum and a liner are used as parts constituting the artificial hip joint. 58 is used. Such a configuration is described, for example, in Patent Document 1 below. In these artificial hip joint components, a spherical femoral head ball 54 is rotatably inserted into a hemispherical concave portion 57 of a cup 56 via a liner 58 .
Here, as materials for the stem 52, the femoral head ball 54, and the cup 56, which require strength, metal materials such as titanium alloys, which are highly compatible with the human body, are used. As for the material of the liner 58, polyethylene or the like is used.

THA is a highly invasive operation in which a considerable amount of living bone is scraped off when each part is attached, and there is a problem that the burden on the patient is large.

In THA, when fixing the cup 56 to the pelvis side, as shown in FIG. Then, the cup 56 is fitted along the formed concave support surface 39, and the cup 56 is fixed to the pelvis 38 side. Therefore, as shown in FIG. 11(B), there is a problem that the joint position _O2 of the artificial hip joint moves significantly compared to the joint position _O1 of the normal hip joint.

Patent Document 2 listed below discloses that an acetabular template is prepared based on three-dimensional image data of the bone shape of the hip joint portion to reduce the invasiveness of THA. However, the acetabular template described in the cited document 2 is made of resin, and is different from the present invention in that it does not integrally include the cup member used for the artificial hip joint.

JP 2012-115368 A Japanese Patent Application Laid-Open No. 2010-110360

Against the background of the circumstances described above, the present invention aims to provide an artificial acetabulum component and a method of manufacturing the same that can reduce the invasiveness of total hip replacement surgery and optimize the joint position of the artificial hip joint. It was made for the purpose.

The artificial acetabulum component of the present invention is made of a metal material,
a cup portion having a hemispherical recess for supporting the ball of the femoral head;
a cup support integrally formed with the cup portion and extending outside the cup portion;
The cup supporting portion is provided with a bone-fitting surface that fits with the uneven surface on the pelvis side,
At least part of the cup portion and/or the cup support portion is composed of a porous structure having a large number of voids.

In the artificial hip joint, the joint position is determined by the position of the cup portion that fits into the femoral head ball. In the artificial acetabular part of the present invention, the cup part is supported by the cup support part. By matching with the shape, it is possible to optimize the joint position in the artificial hip joint.

In addition, since the load acting on the cup portion is received by the cup support portion, the support surface on the pelvis side that is in direct surface contact with the cup portion can be reduced. That is, the bone cutting amount on the pelvic side can be reduced, and the invasiveness can be reduced.

In addition, the artificial acetabular component made of a metal material has a problem that it is very heavy compared to living bones. It is possible to reduce the weight by forming a porous structure having a large number of voids.

Here, in the present invention, a thin skin layer can be formed integrally with the porous structure so as to cover the outer surface of the porous structure.
Even if a portion of the artificial acetabular component is made of a porous structure, providing a skin layer so as to cover the outer surface facilitates ensuring a predetermined strength. Moreover, the manufacturability can be improved when the artificial acetabulum component is modeled by the layered manufacturing method.

Here, through holes can be formed in the skin layer. It is used as a discharge hole for discharging unmelted metal powder remaining in the artificial acetabulum component to the outside when the artificial acetabulum component is modeled by the layered manufacturing method. Further, after the artificial acetabular component of the present invention is fixed to the patient's pelvis, a blood vessel is formed through the through hole to penetrate the epidermis layer from inside to outside.

Further, in the artificial acetabulum component of the present invention, a concave portion can be formed on the side of the cup supporting portion facing the pelvis.
In order to facilitate fixation of the prosthesis component, it is effective to fill the gap between the prosthesis component and the pelvis with a bone graft. In the artificial acetabulum component of the present invention, if a concave portion is provided on the side facing the pelvis, a space for filling the bone graft with the pelvis can be easily secured.

Here, if a through hole is formed in the cup portion in the vicinity of the joint portion with the cup support portion, the graft bone can be inserted through the through hole through the cup portion in the thickness direction and communicated with the recessed portion. A strip can be inserted into the recess.

Next, the method for manufacturing the artificial acetabulum component of the present invention comprises:
a hip joint model obtaining step of obtaining a three-dimensional model of the hip joint reproduced by superimposing CT cross-sectional imaging data or MRI cross-sectional imaging data obtained from the patient's hip joint;
a joint position determination step of determining the joint position on the artificial hip joint side so as to be symmetrical with the joint position on the healthy side using the three-dimensional model;
The shape data of the artificial acetabulum component is set so that the bone-fitting surface of the cup supporting portion fits into the concave-convex surface on the pelvis side in a state in which the cup portion is arranged at the joint position on the artificial hip joint side. a shape data creation step to be created;
and an artificial acetabular component modeling step of modeling the artificial acetabular component by an additive manufacturing method using an alloy powder material based on the shape data.

According to the manufacturing method of the present invention, it is possible to manufacture an artificial acetabulum component that can be suitably arranged at a joint position symmetrical to the joint position on the healthy side of the patient. In addition, according to the layered manufacturing method employed in the manufacturing method of the present invention, a high degree of freedom in shape can be obtained, so it is possible to deal with porous structures having complicated shapes.

Further, in the manufacturing method of the present invention, when creating the shape data of the artificial acetabulum component, model data including a cup portion and a cup support portion is created in advance, and the cup portion is used as the joint on the side of the artificial hip joint. In the state of being placed in position, a portion of the cup supporting portion that overlaps the pelvis can be removed to obtain the surface shape of the bone-fitting surface.

According to the present invention as described above, it is possible to provide an artificial acetabulum component that can reduce the invasiveness of total hip arthroplasty and optimize the joint position of the artificial hip joint, and a method of manufacturing the same.

(A) is a perspective view showing an artificial acetabulum component according to one embodiment of the present invention. (B) is a perspective view showing the same artificial acetabulum component in a different direction from (A). FIG. 2 is a longitudinal cross-sectional view of the artificial acetabular component of FIG. 1; 1. It is the flow which showed the manufacturing procedure of the artificial acetabulum components of FIG. FIG. 4 is an explanatory diagram of a joint position determination step; FIG. 4 is an explanatory diagram of a shape data creating step; FIG. 6 is an explanatory diagram of a shape data creation step following FIG. 5; FIG. 10 is an explanatory diagram for determining the shape of the artificial acetabulum component using model data; FIG. 2 is a diagram showing a state in which an artificial hip joint including the artificial acetabulum component of FIG. 1 is attached; Figure 2 shows a different acetabular component from Figure 1; FIG. 2 is an isolated view of an artificial hip joint used in total hip arthroplasty; (A) is a diagram for explaining a conventional total hip arthroplasty method. (B) is a diagram for explaining problems of conventional total hip arthroplasty.

An embodiment of the present invention will now be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing the external appearance of the artificial acetabulum component 10 of this embodiment, and FIG. The artificial acetabulum component 10 is a member that constitutes an artificial hip joint, is made of a metal material (here, Ti alloy), and includes a cup portion 12 and a cup support portion 20 integrally formed with the cup portion 12 .

The cup portion 12 has a bowl-like shape and has a charging opening 13 that is circular in front view and a hemispherical concave portion 14 . In artificial hip joint replacement surgery, a head ball 54 (see FIG. 10) is accommodated in the hemispherical recess 14 via a liner 58 .

The cup support portion 20 is a plate-like portion that extends toward the outside of the cup portion 12 and is formed integrally with the cup portion 12 . During THA, the cup support 20 is attached to the pelvis so that the longitudinal top 21 faces substantially upward. The cup supporting portion 20 functions as an artificial iliac body that supports the cup portion 12 so that the cup portion 12 is at a predetermined position.

The cup support portion 20 is curved such that the first surface 22 on the charging opening 13 side of the cup portion 12 is convex and the second surface 23 on the opposite side is concave, and the second surface 23 side has a concave portion 24 . is formed. This concave portion 24 functions as a space filled with a bone graft when the artificial acetabular component 10 is attached to the pelvis.

Further, as shown in FIGS. 1B and 2 , in the vicinity of the joining portion of the cup portion 12 with the cup support portion 20, there is a hole extending through the cup portion 12 in the thickness direction to communicate with the concave portion 24. A through hole 25 is formed.

As shown in FIG. 1(B), the peripheral edge of the cup support portion 20 is provided with a substantially U-shaped bone-fitting surface 28 that fits with the bone on the pelvic side. The shape of the bone-fitting surface 28 is determined according to the uneven shape of the bone on the pelvic side of the patient to which the artificial acetabular component 10 is attached, as will be described later. Specifically, when the cup portion 12 of the artificial acetabular component 10 is placed at a desired joint position, the shape is determined so that the bone-fitting surface 28 of the cup support portion 20 fits into the patient's pelvic bone. .

As shown in FIG. 2, in the artificial acetabulum component 10 of this example, the cup supporting portion 20 is composed of a porous structure 20a and a skin layer 20b covering the outer surface thereof. As shown in the partially enlarged view of FIG. 2, the porous structure 20a has a plurality of bar-shaped or plate-shaped small pieces 26 joined together, and gaps 27 are formed in portions other than the small pieces 26. As shown in FIG. By providing such a porous structure 20a, the weight of the artificial acetabulum component 10 can be reduced. The specific shape of the porous structure 20a can be appropriately determined in consideration of its manufacturability and strength.

The skin layer 20b is thinner than the porous structure 20a and formed to cover the porous structure 20a. The skin layer 20b is integrally joined to the radially outward ends of the small pieces 26 located near the outer surface of the porous structure 20a to increase the strength of the artificial acetabular component 10. As shown in FIG. Further, by providing the skin layer 20b so as to cover the porous structure 20a, the manufacturability can be improved when the artificial acetabulum component 10 is modeled using the layered manufacturing method. This skin layer 20b is not limited to the case where it is formed so as to cover the entire porous structure 20a as in this example, but can also be formed so as to cover only a part of the porous structure 20a. .

As shown in FIG. 1, in this example, a plurality of through-holes 34 are formed through the porous structure 20a and the skin layer 20b in the thickness direction. The through hole 34 functions as a discharge hole for discharging unmelted metal powder remaining in the artificial acetabular component 10 when the artificial acetabular component 10 is produced by the layered manufacturing method. Further, after the artificial acetabular component 10 is fixed to the patient's pelvis, a blood vessel is formed through the through hole 34 to penetrate the porous structure 20a and the epidermal layer 20b from inside to outside.

The artificial acetabular component 10 of the present embodiment is formed by additive manufacturing using powder of a titanium alloy such as Ti-6Al-4V, which has excellent biocompatibility. FIG. 3 is a flow showing the manufacturing procedure of this artificial acetabulum component 10. As shown in FIG.

First, the patient's hip joint portion to which the artificial acetabular component 10 is to be attached is sequentially photographed at predetermined intervals of, for example, 100 μm using a non-destructive cross-sectional imaging device 40 such as a CT device or an MRI device. Photographed data is obtained (step S101). Then, the obtained imaging data of each cross section is output in a DICOM (Digital Imaging and Communications in Medicine) format that can be transmitted to a workstation (step S102).

Next, the workstation 42 converts the DICOM-format cross-sectional imaging data into STL (Standard Triangulation Language) format (step S103), and then reads it with the three-dimensional CAD software installed in the workstation 42. , these data are superimposed to reproduce the three-dimensional shape of the hip joint (step S104).

Next, the joint positions in the artificial hip joint are determined based on the obtained three-dimensional shape of the hip joint (step S105). Here, the joint position is the position of the center of rotation of the femoral head (or femoral head ball) supported by the acetabulum (or artificial acetabulum component). Specifically, as shown in FIG. 4, the joint position _O1 is determined from the shape of the normal hip joint on the left side of the figure reproduced on the three-dimensional CAD software, and the position symmetrical with this is determined on the right side of the figure. Assume that the joint position of the artificial hip joint is O ₂ .

Next, the shape of the bone fitting surface 28 of the cup support 20 is determined (step S106). Specifically, as shown in FIG. 5, the cup portion 12 of the artificial acetabulum component 10 is placed at the joint position _O2 . Then, the shape of the bone fitting surface 28 of the cup support portion 20 extending upward from the outer surface of the cup portion 12 is determined according to the shape of the uneven surface 38 a of the pelvis 38 .

Next, at step S107, as shown in FIG. A through-hole 25 is formed in the vicinity of the joint portion so as to pass through the cup portion 12 in the thickness direction and communicate with the concave portion 24 .

Next, a through-hole 34 (see FIG. 1) is formed through the cup support portion 20 in the thickness direction (step S108). At this time, a through hole for inserting a fixing screw may also be provided in the cup supporting portion 20 at the same time.

After the outer shape is determined in this manner, porous processing is performed on the cup support portion 20 (step S109). The respective thicknesses of the skin layer 20b and the porous structure 20a that constitute the outer shell of the cup support portion 20, the specific shape of the porous structure 20a, and the like are determined in consideration of the stress distribution obtained using structural analysis software. decide accordingly.
Thus, the shape data of the artificial acetabulum component 10 is created. That is, steps S106 to S109 described above correspond to the shape data creation step in the present invention.

Note that the method of creating the shape data described above is merely an example. For example, model data including a cup portion and a cup support portion and having recesses 24 and through holes 34 formed therein is prepared in advance. It is also possible to obtain the surface shape of the bone fitting surface 28 by removing the portion 35 overlapping the pelvis 38 in the cup supporting portion 20 in the state of being placed at the joint position O ₂ on the artificial hip joint side. By doing so, steps 106 to 108 can be omitted or simplified, and the number of man-hours required for creating shape data can be reduced.

Next, using a predetermined metal powder material (here, Ti-6Al-4V alloy powder), the artificial acetabular component 10 is modeled by the 3D printer 44 capable of additive manufacturing (step S110). In the 3D printer 44, based on the slice data of the artificial acetabular component 10 created by the three-dimensional CAD software, a powder layer in which the metal powder is evenly spread to a predetermined thickness is scanned with a laser beam to obtain a laser beam at a predetermined position. Melt and solidify the metal powder. This operation is repeated for each cross section (slice data) to obtain a structure with a predetermined shape.

After the layered manufacturing, unnecessary parts are cut off, and then sterilized to obtain the artificial acetabular component 10 having a predetermined shape (step S111).

The artificial acetabulum component 10 obtained in this manner constitutes an artificial hip joint together with the liner 58, stem 52 and femoral head ball 54 shown in FIG. FIG. 8 shows the artificial hip joint including the artificial acetabular component 10 in place.

The artificial acetabular component 10 of the present embodiment has a structure in which the cup portion 12 is supported by the cup support portion 20. The joint position _O2 of the artificial hip joint can be optimized by matching it with the uneven surface shape of _{the patient} 's pelvis 38 side. It can be defined in a symmetrical position.

In addition, in the artificial acetabular component 10 of the present embodiment, the bone-fitting surface 28 of the cup support portion 20 contacts the remaining bone surface 38a on the pelvis 38 side to receive the load acting on the cup portion 12 . Therefore, when the artificial acetabular component 10 is attached, the support surface 39 on the pelvic side that is in direct surface contact with the cup portion 12 can be reduced. That is, the bone cutting amount on the pelvis 38 side can be reduced, and the invasiveness can be reduced.

The artificial acetabulum component 10 of this embodiment is made of a titanium alloy. Titanium alloy parts have a problem of being heavier than living bones, but in the artificial acetabular cup part 10, the weight can be reduced by configuring the cup support part 20 with a porous structure having a large number of voids. is planned. The artificial acetabular component 10 made of a titanium alloy having excellent biocompatibility is integrated with the bone tissue after a certain period of time has passed after being attached to the patient's pelvis.

In the cup support portion 20, a thin skin layer 20b is formed integrally with the porous structure 20a so as to cover the outer surface of the porous structure 20a. It is easy to ensure strength. Moreover, the manufacturability can be improved when the artificial acetabulum component 10 is modeled by the layered manufacturing method.

In the artificial acetabulum component 10 of this embodiment, the cup supporting portion 20 is formed with the through hole 34 . The through hole 34 is used as a discharge hole for discharging unmelted metal powder remaining in the artificial acetabulum component 10 to the outside when the artificial acetabulum component 10 is modeled by the layered manufacturing method. Also, after the artificial acetabular component 10 is fixed to the patient's pelvis 38 , a blood vessel is formed through the through hole 34 so as to penetrate the cup support portion 20 from inside to outside.

Further, in the artificial acetabulum component 10 of the present embodiment, a concave portion 24 is formed on the side of the cup supporting portion 20 facing the pelvis 38, and a bone graft is packed between the artificial acetabulum component 10 and the pelvis 38. You can easily secure a space for

In the artificial acetabular lid component 10 of the present embodiment, a through hole 25 is formed in the cup portion 12 in the vicinity of the joint portion with the cup support portion 20 so as to pass through the cup portion 12 in the thickness direction and communicate with the concave portion 24 . Therefore, the bone graft can be inserted into the recessed portion 24 through the through hole 25 .

The artificial acetabular component 10 of the present embodiment is based on the three-dimensional shape of the hip joint reproduced by superimposing CT cross-sectional imaging data or MRI cross-sectional imaging data acquired from the patient's hip joint, and the joint position O ₁ on the healthy side. The joint position O ₂ on the side of the artificial hip joint is determined so as to be symmetrical with , and the cup portion 12 is placed at the joint position O ₂ on the side of the artificial hip joint. Shape data of the artificial acetabulum component 10 is created so as to fit with the uneven surface on the pelvis 38 side.

Therefore, according to the manufacturing method of the present embodiment, it is possible to manufacture the artificial acetabulum component 10 that can be suitably arranged at a joint position symmetrical to the joint position on the healthy side of the patient.

Further, according to the manufacturing method of the present embodiment, since the artificial acetabular component 10 is formed by the layered manufacturing method using the Ti alloy powder material, a high degree of freedom in shape is obtained, and the porous structure 20a having a complicated shape is obtained. can also correspond to

FIG. 9 is a diagram showing an artificial acetabulum component 10B different from the above embodiment. As shown in the figure, in the artificial acetabulum component 10B, in addition to an upper cup support portion 20 extending above the cup portion 12, a lower cup support portion 20B extending below the cup portion 12 is formed. A bone-fitting surface 28B that fits with the bone on the pelvic side is also provided on the periphery of the lower cup support portion 20B. According to the artificial acetabulum component 10B of this example, the cup part 12 can be supported from two directions above and below.

Although the embodiments of the present invention have been described in detail above, these are only examples. Although the above embodiment is an example in which the cup support portion 20 is provided with a porous structure, it is also possible to provide the cup portion 12 with a porous structure, and both the cup portion and the cup support portion are provided with a porous structure. It is also possible to In addition, the skin layer covering the outer surface of the porous structure can be provided only on a part of the porous structure. is.

REFERENCE SIGNS LIST 10, 10B Artificial acetabular component 12 Cup portion 14 Hemispherical concave portion 20, 20B Cup supporting portion 20a Porous structure 20b Skin layer 24 Recessed portion 25 Through hole 28, 28B Bone fitting surface 38 Pelvis 38a Concave and convex surface 54 Head ball O ₁ , O ₂ joint position

Claims (5)

made of metal material,
a cup portion having a hemispherical recess for supporting the ball of the femoral head;
a cup support integrally formed with the cup portion and extending outside the cup portion;
The cup supporting portion is provided with a bone-fitting surface that fits with the uneven surface on the pelvis side,
At least part of the cup portion and/or the cup support portion is composed of a porous structure having a large number of voids,
The cup supporting portion has a concave portion formed on the side facing the pelvis,
An artificial acetabulum component, wherein a through hole is formed in the cup portion in the vicinity of a joint portion with the cup support portion, the through hole passing through the cup portion in a thickness direction thereof and communicating with the recessed portion. . 2. The artificial acetabular component according to claim 1, wherein a thin skin layer is integrally formed with the porous structure so as to cover the outer surface of the porous structure. 3. The artificial material according to claim 1, wherein said porous structure comprises a plurality of rod-like or plate-like small pieces connected to each other, and said voids are formed in portions other than said small pieces. acetabulum component. A method for manufacturing an artificial acetabulum component according to any one of claims 1 to 3 ,
a hip joint model obtaining step of obtaining a three-dimensional model of the hip joint reproduced by superimposing CT cross-sectional imaging data or MRI cross-sectional imaging data obtained from the patient's hip joint;
a joint position determination step of determining the joint position on the artificial hip joint side so as to be symmetrical with the joint position on the healthy side using the three-dimensional model;
The shape data of the artificial acetabulum component is set so that the bone-fitting surface of the cup supporting portion fits into the concave-convex surface on the pelvis side in a state in which the cup portion is arranged at the joint position on the artificial hip joint side. a shape data creation step to be created;
A method of manufacturing an artificial acetabular component, comprising: an artificial acetabular component modeling step of modeling the artificial acetabular component by an additive manufacturing method using an alloy powder material based on the shape data. When creating the shape data of the artificial acetabulum component,
A model data having a cup part and a cup support part is created in advance,
A surface shape of the bone-fitting surface is obtained by removing a portion of the cup supporting portion that overlaps the pelvis in a state in which the cup portion is arranged at the joint position on the side of the artificial hip joint. 5. A method of manufacturing an artificial acetabulum component according to claim 4 .

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