JP2010178973A - Socket for artificial joint, artificial hip joint using the same, and spherical head pressing tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a socket for an artificial joint, easily inserting a spherical head in a recessed spherical surface part of the socket after the socket is fixed to the pelvis, and having a fixed slip-off preventing function, in an artificial joint of such a type that, after the socket is fixed to the pelvis, the spherical head serving as a bone head is inserted in the recessed spherical surface part of the socket. <P>SOLUTION: This socket 13 for an artificial joint is mounted to the pelvis 19 side after the bone head is removed, and shaped substantially like a hemispherical shell to slidably support the spherical head 11 fixed to a neck part 14 of an artificial bone (a stem) buried in the bone side. In the socket, (1) the socket 13 is formed such that the recessed spherical surface part 13a receiving the spherical head is formed extending over the hemisphere line to cover the spherical head 11 exceeding the diameter equatorial plane, and (2) the opening side edge part of the hemispherical shell is provided with cutout grooves (31-38). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an artificial joint, and more particularly to an artificial hip joint with a dislocation prevention mechanism.

  In a joint, an artificial joint may be given when a functional disorder occurs due to trauma or disease. Examples of the artificial joint include an artificial hip joint, an artificial knee joint, an artificial shoulder joint, an artificial elbow joint, and an artificial ankle joint depending on the type of joint. For example, taking the artificial hip joint as an example, the structure of the artificial joint will be described.

As shown in FIG. 1, the artificial hip joint 1 is generally composed of components such as an artificial bone (stem) 12 having a spherical head 11 at the tip and a hemispherical socket 13. The main body portion of the stem 12 is a portion that is inserted and fixed in the medullary cavity of the femur 18, and a neck portion 14 is formed on the stem 12, and the spherical head 11 is disposed in this portion. The socket 13 is attached to the acetabulum 19 after removing the hip joint head, the spherical head 11 is fitted inside the spherical shell of the socket 13, and the stem 12 can be freely rotated around the socket 13. Has been.
Usually, the stem 12, the spherical head 11, and the socket 13 are formed of a metal or a ceramic material that is not harmful to a living body (see Patent Document 1 and Patent Document 2).

When such an artificial hip joint or the like is attached to the pelvis of a living body, generally, the socket 13 is first inserted into the hip joint portion (generally recessed in a hemispherical shape) of the pelvis, screwed, and then the spherical head 11. There is a method of inserting the socket 13 into the socket 13 and a method of fixing the socket 13 after inserting the spherical head 11 into the socket 13.
The former can be fixed with screws or the like, while the latter uses an adhesive such as cement. In the case of fixing with an adhesive such as cement, screw fixing that can be surely fixed in the initial stage is often used together.

When the socket 13 is fixed to the pelvis with a screw, the screw needs to be screwed from the inside of the socket 13 toward the pelvis. The spherical head 11 is fixed to the concave spherical surface portion 13a in the socket 13 after the socket 13 is fixed to the pelvis. Will be inserted. In order to facilitate the insertion of the spherical head 11, the concave spherical surface portion 13a of the socket 13 is formed to be hemispherical or shallower. As a result, there is a problem that the spherical head 11 is easily removed from the concave spherical surface portion 13a of the socket 13 and is easily dislocated until the muscle is regenerated and strengthened after the operation.
In order to prevent such dislocation, a cylindrical portion is also added to the flange of the concave spherical surface portion 13a of the socket 13.

  Some human artificial joints use a C-ring or the like to prevent dislocation, but such a method has a complicated structure and is difficult to apply to a small artificial joint. In addition, since the cost is high, in the case of an artificial joint for human beings, a dislocation prevention mechanism is not provided, and it is often the case that the muscle is regenerated and strengthened for a certain period of time after the operation to rest.

  On the other hand, in the case of animals such as dogs, it is difficult to rest for a certain period after the operation, and there is a problem that dislocations in which the spherical head 11 comes off from the socket 13 frequently occur during this period.

JP-T 60-500657 JP 2008-54788 A

  Under such circumstances, it can also be applied to small artificial joints, and it can prevent the dislocation of the spherical head that becomes the bone head from the socket even in cases where it is difficult to rest for a certain period after surgery, such as a puppy. Joints are anxious, especially veterinarians handling animals such as dogs, and there is a strong demand for such artificial joints and instruments that support the surgery.

  In view of the above circumstances, the present invention is a type of artificial joint in which a spherical head that becomes a bone head is inserted into the concave spherical surface portion of the socket after the socket is fixed to the pelvis. It is an object of the present invention to provide a socket for an artificial joint that can be easily inserted into a concave spherical portion, and that the spherical head does not easily come out of the concave spherical portion of the socket after insertion, that is, has a certain drop prevention function. To do.

  It is another object of the present invention to provide a socket for an artificial joint that can easily adjust a force necessary for inserting the spherical head into the concave spherical surface portion of the socket or a force necessary for removing the spherical head (prevention force).

As a result of various studies, the present inventor has completed the socket for an artificial joint according to the present invention, an artificial hip joint using the socket, and a spherical head pushing instrument.
That is, in order to solve the above problem, the socket for an artificial joint according to the present invention is
It is mounted on the pelvis side after removing the bone head, and is shaped like a substantially hemispherical shell to slidably support a spherical head fixed to the neck of an artificial bone (stem) embedded on the bone side. ,
As its features,
1) The socket has a concave spherical portion that receives the spherical head and extends beyond the hemispherical line so as to cover the spherical head beyond the diameter equatorial plane.
And,
2) A cut groove is provided in the opening side collar of the hemispherical shell,
It has a configuration.

According to this configuration, since the cut groove is provided in the flange portion on the opening side of the spherical shell of the socket, the spherical head can be easily inserted into the concave spherical surface portion of the socket even after the socket is fixed to the pelvis. .
In addition, the socket is formed with a concave spherical portion that receives the spherical head extending beyond the hemispherical line so as to cover the spherical head beyond the diameter equatorial plane. Since the depth of the concave spherical portion to be inserted is deeper than the hemisphere, the spherical head does not easily come out of the concave spherical portion of the socket after insertion. That is, it is possible to realize a certain omission prevention function.

Further, in the socket for an artificial joint according to the present invention, the opening rigidity of the opening side flange of the socket is defined by using the groove width, the groove depth, the number of grooves, and the groove arrangement in the cut groove as parameters. Reduction adjustment can be performed to a predetermined strength.
Thereby, it is possible to easily adjust the force required for inserting the spherical head into the concave spherical surface portion of the socket or the force required for removing the spherical head (prevention force).

Moreover, in the socket for artificial joints according to the present invention, it is preferable that the thickness of the opening side collar is made smaller than that of the socket main body shaped like a hemispherical shell.
When the spherical shell is thick or has a metal outer shell, it is necessary to make a considerably deep cut. If a deep cut is made, the contact between the socket and the pelvis may be adversely affected. Therefore, the opening stiffness can be more effectively reduced by thinning the spherical shell in the part with the notch, that is, by reducing the thickness of the opening side flange of the socket.

  Further, from another viewpoint of the present invention, even when it is difficult to make a certain period of time after surgery for a puppy or the like using the above-described socket for an artificial joint of the present invention, a spherical shape that becomes a bone head from the socket. An artificial joint, in particular an artificial hip joint, is provided that can prevent the head from dislocation.

Further, from another aspect of the present invention, a device that is detachable from the socket for an artificial joint of the present invention,
1) at least two or more arm portions having a screw portion that can be screwed into a socket at the tip;
2) a main body part capable of holding the arm part;
3) fixing means for fixing the arm part and the main body part;
4) A pushing guide portion attached to the main body portion, the pushing guide portion of the stem for pushing the center of the spherical head into the concave spherical portion of the socket toward the diameter center of the socket;
A spherical head pushing tool is provided.

According to the spherical head pushing instrument having such a configuration, it is possible to avoid applying an excessive load to the pelvis to which the socket is fixed when the spherical head is inserted into or extracted from the concave spherical portion of the socket.
Further, the center of the spherical head can be surely inserted toward the center of the concave spherical surface portion of the socket via the push guide portion attached to the main body portion. That is, the spherical head can be easily inserted into the concave spherical portion of the socket.
As described above, the spherical head push-in device having the above-described configuration can be used as a device for assisting an artificial joint implantation operation.

  According to the socket for an artificial joint of the present invention, even in a small artificial joint in which a dislocation prevention mechanism cannot be attached or in a case where it is difficult to rest for a certain period after an operation such as a puppy, It has the effect that it can prevent that the spherical head which becomes becomes dislocation.

  Further, according to the spherical head pushing instrument of the present invention, it is possible to avoid applying an excessive load to the pelvis during the implantation of the artificial joint, and the spherical head is surely directed toward the center of the concave spherical portion of the socket. Therefore, the spherical head can be easily inserted into the concave spherical surface of the socket.

It is explanatory drawing of an artificial hip joint. It is an enlarged view of the socket and spherical head in the conventional artificial joint. (1) is a schematic cross-sectional view of a state in which the spherical head is inserted into the concave spherical portion of the socket, and (2) is a schematic diagram of the concave spherical portion of the socket as viewed from the spherical head side. It is an enlarged view of the socket and spherical head in the artificial joint of Example 1. (1) is a schematic cross-sectional view of the state in which the spherical head is inserted into the concave spherical portion of the socket, and (2) is a schematic view of the concave spherical portion of the socket as viewed from the spherical head side. It is an enlarged view of the socket and spherical head in the artificial joint of Example 2. (1) is a schematic cross-sectional view of a state in which the spherical head is inserted into the concave spherical portion of the socket, and (2) is a schematic diagram of the concave spherical portion of the socket as viewed from the spherical head side. It is a front view of the socket for artificial hip joints of Example 1. FIG. 1 is a schematic cross-sectional view of a socket for an artificial hip joint of Example 1. FIG. It is explanatory drawing of one Embodiment of the spherical head pushing instrument of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, an embodiment of a conventional socket for an artificial joint will be described with reference to FIG.
Usually, the socket for an artificial joint is mounted using a screw 20 on the pelvis 19 side after removing a bone head (not shown). In order to fix the socket 13 to the pelvis with a screw, the screw 20 is screwed from the inside of the socket 13 toward the pelvis. A socket 13 is slidably supported to support the spherical head 11 fixed to the neck portion 14 of an artificial bone (stem) embedded in the bone side (12 in FIG. 1 and not shown in FIG. 2). Is shaped like a substantially hemispherical shell. The spherical head 11 is inserted into the concave spherical surface portion 13a in the socket 13 after fixing the socket 13 to the pelvis.

  In the case of the conventional socket for artificial joints, in order to facilitate the insertion of the spherical head 11, the concave spherical surface portion 13a of the socket 13 is formed up to the hemispherical line as shown in FIG. . As a result, there is a problem that the spherical head 11 is easily removed from the concave spherical surface portion 13a of the socket 13 and is easily dislocated until the muscle is regenerated and strengthened after the operation. As described above, in order to prevent such dislocation, a cylindrical portion is also added to the flange of the concave spherical surface portion 13a of the socket 13.

  On the other hand, in the socket for artificial joints of the present invention, compared with the socket for artificial joints of the present invention, mainly 1) the socket 13 is a recess for receiving the spherical head so as to cover the spherical head 11 beyond the hemispherical line. The spherical portion 13a is formed so as to extend beyond the hemispherical line, and 2) is characterized in that a notch groove is provided in the opening side collar of the hemispherical shell.

  A concave spherical portion for receiving the spherical head is formed to extend beyond the hemispherical line so that the socket covers the spherical head beyond the diameter equatorial plane. It is designed not to easily come off the spherical surface. However, if the concave spherical portion that receives the spherical head is formed to extend beyond the hemispherical line, the spherical head cannot be easily inserted into the concave spherical portion of the socket, and is more difficult after the socket is fixed to the pelvis. Would be an undue burden on the pelvis. Therefore, a cut groove is provided in the heel portion of the socket on the opening side of the socket so that the spherical head can be easily inserted into the concave spherical portion of the socket even after the socket is fixed to the pelvis.

  In more detail, the concave spherical portion of the socket extends beyond the hemispherical line so that the concave spherical portion inside the socket that accepts the spherical head can be made deeper than the hemisphere. Since the radius of the entrance of the opening of the hemispherical socket into which the head is inserted is smaller than the radius of the spherical head, once the spherical head enters the concave spherical surface of the socket, it cannot be easily removed.

  On the other hand, since the diameter of the entrance of the socket opening is smaller than the spherical head, it is necessary to widen the entrance of the opening in order to insert the spherical head, but the opening of the metal hemispherical socket with a certain thickness is required. A large force is required to widen the entrance of the unit by a certain amount (open mouth). This is because the spherical shell structure has high rigidity with respect to the force spreading from the inside, and the rigidity (Young's modulus) of the metal that is the material is large (open mouth rigidity).

  The spherical head needs to be inserted after the concave spherical portion inside the socket is fixed to the pelvis during the operation, and a large force is not applied in such an environment. Even if a large force is applied using some kind of jig, the deformation will be in a mode in which the end of the inner cup made mainly of a soft material such as polyethylene is deformed (collapsed), and it is inevitable that it will be easily removed after insertion. .

  In order to insert the inner cup with a force that does not cause the end of the inner cup to collapse, the depth of the concave spherical surface inside the socket becomes extremely small. In addition to processing accuracy, polyethylene is an example of the material of the socket and inner cup. Also, cobalt chromium, which is an example of the material of the spherical head, may be easily removed due to a difference in coefficient of thermal expansion and a temperature change, and manufacturing and management become extremely difficult.

  Therefore, in the artificial joint socket according to the present invention, the opening stiffness of the concave spherical portion inside the socket is greatly increased by inserting a notch groove at a certain depth in the opening side flange of the hemispherical socket. We decided to reduce it.

  Further, the opening stiffness depends on the number of the cut grooves (the interval and arrangement of the cut grooves) in addition to the depth of the cut grooves. Therefore, the opening stiffness can be arbitrarily adjusted by combining these. If the appropriate number is used, the depth of the cut groove is about several millimeters, so that the opening stiffness is easily adjusted and managed. Since the depth of the socket can be increased, the diameter of the socket end is reduced by about 1 mm, so that there is no problem with the influence of temperature change.

  If it is attempted to adjust the opening stiffness without using the above-mentioned cut groove, the diameter of the socket ridge needs to be kept extremely slightly larger than the diameter of the spherical head, resulting in slight machining dimensional error and temperature. Due to the fluctuation, it becomes difficult to insert the spherical head, or the spherical head once inserted may come off.

  In addition, when the inner cup is thin, the rigidity of the inner cup is significantly lower than that of the metal outer cup, combined with the low Young's modulus of the material polyethylene, so the inner cup does not necessarily have a notch (slit). It may not be necessary. Since polyethylene and other materials are too ductile and trying to insert slits (slits) by machining, burrs are generated and man-hours are required for the treatment. It is also very significant in manufacturing.

In the following Examples 1 and 2, an embodiment of the socket for an artificial joint of the present invention will be described. Moreover, Example 3 demonstrates one Embodiment of the spherical head pushing instrument of invention.
The following examples merely serve to illustrate the present invention, and the present invention is defined by the claims. The embodiments described below can be devised for various modifications and alternative embodiments without departing from the spirit and scope of the present invention.

FIG. 3 is an enlarged view of the socket and the spherical head in the artificial joint of Example 1, and FIG. 3 (1) is a schematic cross-sectional view of the state in which the spherical head is inserted into the concave spherical portion of the socket. 2) is a schematic view of the concave spherical surface portion of the socket as viewed from the spherical head side.
The socket for artificial joint 13 according to the first embodiment is mounted on the pelvis 19 side after removing the bone head, and can slide the spherical head 11 fixed to the neck portion 14 of the artificial bone (stem) embedded in the bone side. The socket 13 is shaped in a substantially hemispherical shell shape, and 1) the socket 13 has a concave spherical surface portion 13a for receiving the spherical head so as to cover the spherical head 11 beyond the diameter equatorial plane. Is formed so as to extend beyond the hemispherical line, and 2) a cut groove (31-38) is provided in the opening side collar of the hemispherical shell.

  The artificial joint socket 13 according to the first embodiment is formed so that a concave spherical surface portion 13a for receiving a spherical head extends beyond the hemispherical line as compared with a conventional artificial joint socket (see FIG. 2) (13c). ). Further, as shown in FIG. 3 (2), cut grooves (31 to 38) are provided in the hemispherical opening-side flange (13d) formed to extend.

  In the socket for an artificial joint of Example 1 described above, when the spherical shell is thick or has a strong metal outer shell, it is necessary to provide a considerably deep incision groove for the close contact between the socket and the pelvis. There is a possibility of adverse effects. In Example 2, an embodiment in which the opening stiffness can be more effectively reduced without providing a deep cut groove will be described.

4 is an enlarged view of the socket and the spherical head in the artificial joint of Example 1. FIG. 4 (1) is a schematic cross-sectional view of the state in which the spherical head is inserted into the concave spherical portion of the socket. 2) is a schematic view of the concave spherical surface portion of the socket as viewed from the spherical head side.
Similar to the artificial joint socket of the first embodiment, the artificial joint socket 13 of the second embodiment is mounted on the pelvis 19 side after the bone head is removed, and the neck portion of the artificial bone (stem) embedded in the bone side. In order to slidably support the spherical head 11 fixed to 14, it is shaped like a substantially hemispherical shell. The features are as follows: 1) The socket 13 exceeds the diameter equatorial plane with respect to the spherical head 11. A concave spherical surface portion 13a for receiving the spherical head is formed to extend beyond the hemispherical line so as to cover, and 2) a cut groove (41 to 48) is provided in the opening side collar of the hemispherical shell shape, 3) The thickness of the opening side flange of the socket 13 is smaller than that of the socket body shaped like a hemispherical shell.

Specifically, the thickness of the opening side flange in the socket 13 is made smaller than that of the socket body shaped like a hemispherical shell, as shown in FIG. ) Is made smaller than the opening side flange (13d) in the socket 13 of the first embodiment shown in FIG. Since the thickness of the opening side flange is smaller than that of the socket body shaped like a hemispherical shell, the opening side flange is stepped (13e, 13f, 13g).
By making the thickness of the opening side flange in the socket 13 smaller than that of the socket body shaped like a hemispherical shell, that is, by reducing the thickness of the spherical shell on the concave spherical portion inside the socket where the cut groove is provided Even when the spherical shell has a large thickness or has a strong metal outer shell, the opening stiffness is effectively reduced without providing a deep cut groove.

(About spherical head pusher)
In Example 3, a spherical head pushing tool will be described. FIG. 7 is an explanatory view of an embodiment of the spherical head pushing instrument of the present invention.
As shown in FIG. 7, a spherical head pushing instrument 100 is an instrument that is detachable from the socket for an artificial joint of the present invention,
(1) Two arm portions (81, 91) having screw portions (83, 92) that can be screwed into the socket 13 at the tips;
(2) a main body 101 capable of holding two arm portions (81, 91);
(3) Tightening bolts (84, 85, 94, 95) that are fixing means for fixing the two arm portions (81, 91) and the main body portion 101;
(4) A pushing guide portion that is attached to the main body portion 101, and is a stem pushing guide portion (102, 102) for pushing the center of the spherical head 11 into the concave spherical portion 13 a of the socket 13 toward the diameter center of the socket 13. 103, 104).

According to the spherical head pushing instrument, when the spherical head 11 is inserted into or removed from the concave spherical surface portion 13a of the socket 13, an excessive load is applied to the pelvis (not shown) to which the socket 13 is fixed. In addition, the center of the spherical head 11 is securely inserted toward the center of the concave spherical surface portion 13a of the socket 13 through the push guide portions (102, 103, 104) attached to the main body portion 101. be able to.
By using the spherical head pushing tool, the spherical head 11 can be easily inserted into the concave spherical surface portion 13 a of the socket 13.

(Other examples)
(1) In the above-described embodiment, eight cut grooves are provided in the opening side flange of the socket. However, the depth of the cut grooves, the groove interval, and the groove arrangement are provided according to the requirement of the opening rigidity. It can be designed freely in relation to the shape of the groove. Also, the number of cut grooves, groove depth, groove spacing, groove arrangement, and groove shape can be freely designed depending on the shape of the socket itself. 5 and 6 show an embodiment in which the socket 13 itself has a hemispherical shape in which the upper end is cut, and the socket having the shape is provided with seven cut grooves (51 to 57). .
(2) In the above-described embodiment, the socket is first inserted into the pelvis, screwed, and then used as the socket for an artificial joint used in the method of inserting the spherical head into the socket. The joint socket may be used for a method of fixing the socket with an adhesive or the like after inserting the spherical head into the socket.

  The present invention is useful as an artificial hip joint, an artificial shoulder joint, and an assisting device for the treatment thereof.

1 Artificial hip joint 11 Spherical head 12 Stem (artificial bone)
13 Socket 13a Concave spherical surface portion 14 Neck portion 18 Femur 19 Pelvis (acetabulum)
21 Screw head 31-38, 41-48, 51-57 Cut groove 81, 91 Arm part 100 Spherical head pushing instrument 101 Main body part

Claims (5)

Artificial joint shaped like a substantially hemispherical shell, slidably supported by a spherical head fixed on the neck of an artificial bone (stem) that is attached to the pelvis after the bone head has been removed Socket for
The socket is formed such that a concave spherical portion that receives the spherical head extends beyond the hemispherical line so as to cover the spherical head beyond the diameter equatorial plane, and the hemispherical shell-shaped opening side A socket for an artificial joint, characterized in that a cut groove is provided in the buttocks.   In the slit groove, the opening rigidity of the opening side flange portion of the socket is adjusted to a predetermined strength by using the groove width, groove depth, number of grooves, and groove arrangement as parameters. The socket for artificial joints according to claim 1.   The socket for an artificial joint according to claim 1, wherein a thickness of the opening side flange portion of the socket is made smaller than that of the socket main body shaped in a hemispherical shell shape.   The artificial hip joint comprising the artificial joint socket according to claim 1, wherein the artificial joint is an artificial hip joint. A device detachable from the socket for artificial joints according to any one of claims 1 to 3,
At least two or more arm portions having a screw portion that can be screwed with the socket at the tip;
A main body portion capable of holding the arm portion;
Fixing means for fixing the arm part and the main body part;
A push guide portion attached to the main body, the push guide portion of the stem for pushing the center of the spherical head into the concave spherical portion of the socket toward the diameter center of the socket;
A spherical head pushing instrument characterized by comprising: