Artificial hip joint wide acetabular cup removal device

Abstract

The acetabular cup removal device for artificial hip joints according to an embodiment of the present invention includes a main shaft and a cutter unit that cuts the acetabular portion while rotating around the main shaft. The cutter unit includes a cutter tilt unit that can be tilted along the acetabular portion around a virtual tilt axis, a cutter mounting unit that is slidably coupled to the cutter tilt unit in a direction approaching or moving away from the virtual tilt axis, and a cutter detachably mounted on the cutter mounting unit. The cutter tilt unit includes a first through hole penetrating along the virtual tilt axis, a connecting bar having both ends fixed to the cutter mounting unit, and a leaf spring fixed to both ends of the connecting bar and having a central portion between both ends.

Description

Technical Field

[0001] The present invention relates to a device for removing a wide acetabular cup for an artificial hip joint.

Background Art

[0002] Generally, an artificial hip joint is a substitute used for the purpose of replacing a hip joint when its function is impaired. It is implanted at the site where the hip joint was located and can maintain normal activities.

[0003] Such an artificial hip joint is divided into a hemispherical acetabular cup having a liner that serves as a bearing and inserted into the wide acetabular region of the pelvis, a stem attached to the femur, and a hemispherical head provided at the end of the stem for replacing the femoral head and inserted into the acetabular cup.

[0004] Therefore, patients who do not function normally due to arthritis, dysplasia, sequelae of trauma or infection and feel pain in the hip joint can restore the joint's motor function and relieve pain by replacing the painful hip joint with the above artificial hip joint.

[0005] On the other hand, such artificial hip joints wear out with long-term use. In particular, the acetabular cup that rubs against the head has a high wear rate due to continuous joint use. When the wear progresses, osteolysis may occur around the wide acetabulum of the pelvis where the acetabular cup is inserted. For this reason, techniques for removing an already inserted acetabular cup from the wide acetabulum of the pelvis have been continuously developed.

[0006] In connection with this, the applicant of the present application has developed an acetabular cup removal device for artificial hip joints disclosed in Korean Registered Patent No. 10-2103774 as shown in FIGS. 1 to 4. For reference, FIGS. 1 to 4 respectively correspond to FIGS. 1, 4, 3, and 7 of the above Korean registered patent, and for convenience of explanation, the reference numerals of the drawings are shown as they are without modification. Also, even if the same reference numerals as those used in the description of the present invention to be described later are used, they do not necessarily refer to the same components.

[0007] The conventional acetabular cup removal device 100 moves the stepless adjustment unit 140 forward and removes the acetabular cup from the acetabulum of the pelvis while sequentially tilting the cutter 1501 forward (counterclockwise) (see FIG. 4). Also, when the acetabular cup (C) is spherical (a shape obtained by cutting off half of a sphere), the acetabular cup C can be removed using a cutter 1501 suitable for the radius of the corresponding acetabular cup (see FIG. 5(a)).

[0008] However, when the acetabular cup C is elliptical (a shape obtained by cutting off half along the minor axis of an ellipse), when the cutter 1501 tilts in the direction of the major axis A of the ellipse while moving toward the apex O of the acetabular cup during cutting, it gets caught on the outer surface (the part indicated by ★) of the acetabular cup C and cannot proceed normally, or in severe cases, the cutter is damaged (at the 60° rotation in FIG. 5(b)). To address this, a cutter with a larger radius can be used, but in this case, there is a problem that the bone loss of the patient increases.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] The technical problem of the present invention aims to solve the problems of the above-described conventional acetabular cup removal device. In the case of not only circular acetabular cups but also elliptical acetabular cups, an artificial hip joint acetabular cup removal device is provided that can smoothly tilt the acetabular cup while the cutter does not catch on the outer surface of the acetabular cup and remove the acetabular cup from the acetabulum of the pelvis.

Means for Solving the Problem

[0011] To achieve the above object, an artificial hip joint acetabular cup removal device according to an embodiment of the present invention is attachable to a power tool and rotatable by the driving force of the power tool. It includes a main shaft and a cutter portion provided at the front end of the main shaft. The cutter portion is tiltable along the acetabular portion where the acetabular cup is implanted and cuts the acetabular portion while rotating by the main shaft. The cutter portion includes a cutter tilt portion tiltable along the acetabular portion around a virtual tilt axis, a cutter mounting portion slidably coupled to the cutter tilt portion in a direction approaching or separating from the virtual tilt axis, and a cutter detachably attached to the cutter mounting portion. The cutter tilt portion includes a first through hole penetrated along the virtual tilt axis, a connecting bar with both ends fixed to the cutter mounting portion, and a leaf spring with both ends fixed to the connecting bar and having a central portion between the two ends.

[0012] Further, the main shaft includes a cylinder portion inserted into the first through hole and having a second through hole formed in its longitudinal direction. The connecting bar is slidably disposed in the second through hole in a direction approaching or separating from the virtual tilt axis within the second through hole, and the central portion of the leaf spring is supported by the inner wall of the second through hole.

[0013] Furthermore, the second through hole has a circular cross-section, the connecting bar has an arc shape with a part of its circumference having the same radius of curvature as the radius of curvature of the second through hole, and can be in surface contact with the second through hole.

[0014] Furthermore, other parts of the connecting bar except for this part do not contact the second through hole.

[0015] Furthermore, the cutter mounting part includes a cutter mounting part main body having a third through hole into which the connecting bar is inserted. The connecting bar does not rotate relative to the cutter mounting part main body within the third through hole and is tilted in conjunction with the tilting of the cutter mounting part.

[0016] The other parts of the connecting bar have three sides that are perpendicular to and connected to each other, and the third through hole forms a rectangular cross-section.

[0017] Furthermore, the cutter tilt part covers the cutter mounting part main body and further includes a cover fixed to the opposing surface of the cutter tilt part.

[0018] On the inner surface of the cover, a groove part corresponding to the contour of the cutter mounting part main body is formed, and a gap is formed between the upper end of the cutter mounting part main body and the upper end of the groove part of the cover.

[0019] Furthermore, in an initial state where no external force acts on the leaf spring, this part of the connecting bar contacts the second through hole. When an external force acts on the leaf spring, the leaf spring is compressed and this part of the connecting bar is separated from the second through hole.

[0020] Furthermore, the cover is fixed to the opposing surface of the cutter tilt part by a fastener fixed to the connecting bar so as not to move relative to it.

Advantages of the Invention

[0021] The artificial hip joint acetabular cup removal device according to the embodiment of the present invention having the above-described configuration can have the following effects.

[0022] According to an embodiment of the present invention, different from the prior art, even in the case of an oval acetabular cup, the cutter can tilt to the apex of the acetabular cup while smoothly moving along the surface of the acetabular cup, so that it is possible to easily remove the acetabular cup from the acetabulum of the pelvis.

[0023] Note that the effects of the present invention are not limited to this, and other effects derived from the configuration of the present invention described later are also included.

Brief Description of the Drawings

[0024]

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DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0026] In addition, the present invention newly derives a configuration related to the coupling of the cutter tilt portion and the cutter mounting portion in an existing acetabular cup removing device for artificial hip joints (Korean Registered Patent No. 10-2103774) invented by the applicant in order to solve the above-described problems. Therefore, in order to clarify the gist of the present invention, the configuration directly related to the present invention will be mainly described below, and the description of other configurations not related to the gist of the present invention will be simplified or omitted.

[0027] Also, the expressions such as "first", "second", "third", etc. used in this embodiment do not mean an order, but are terms used to distinguish components having the same name from each other.

[0028] As shown in FIG. 6, a wide acetabular cup removal device for an artificial hip joint according to an embodiment of the present invention (hereinafter simply referred to as "wide acetabular cup removal device") is a wide acetabular cup removal device for an artificial hip joint that can be attached to a known power tool P equipped with a battery and a motor.

[0029] The wide acetabular cup removal device of the present invention includes a main shaft 2 and a cutter unit 3.

[0030] The main shaft 2 is rotatable by the driving force of the power tool P.

[0031] The cutter unit 3 is provided at the front end of the main shaft 2, can be tilted along the acetabular portion where the wide acetabular cup is implanted, and cuts the acetabular portion while rotating by the main shaft 2.

[0032] As shown in FIG. 7, the cutter unit 3 includes a cutter tilt portion 31, a cutter mounting portion 32, and a cutter 33 detachably mounted on the cutter mounting portion 32.

[0033] As shown in FIG. 7, the cutter unit 3 includes a cutter tilt portion 31, a cutter mounting portion 32, and a cutter 33 detachably mounted on the cutter mounting portion 32.

[0034] The cutter tilt portion 31 can be tilted along the acetabular portion about a virtual tilt axis A.

[0035] Specifically, as shown in FIGS. 9, 17, and 18, the cutter tilt portion 31 includes a first through hole 311, a fourth through hole 314, a connecting bar 312, and a leaf spring 313.

[0036] The first through hole 311 is formed to penetrate the cutter tilt portion 31 in the lateral direction (the direction of the paper surface based on a in FIG. 17) along the virtual tilt axis A. Further, the first through hole 311 can have a circular cross section.

[0037] The fourth through-hole 314 is formed to penetrate in a direction perpendicular to the virtual tilt axis A, that is, in the longitudinal direction of the cutter tilt portion 31 (the direction of the paper surface based on the b reference in FIG. 17).

[0038] On the other hand, the main shaft 2 penetrates through the fourth through-hole 314 of the cutter tilt portion 31 (see FIG. 8). Further, the main shaft 2 includes a cylinder portion 22 that is inserted into the first through-hole 311 of the cutter tilt portion 31 (see FIGS. 9 and 16).

[0039] The cutter tilt portion 31 is rotatable relative to the cylinder portion 22.

[0040] A second through-hole 21 is formed in the cylinder portion 22 in its longitudinal direction (see FIGS. 10 and 16). As shown in FIGS. 8, 12, and 15, the connecting bar 312 is slidable in a direction approaching or moving away from the tilt axis A within the second through-hole 21, passes through the second through-hole 21, and both ends are fixed to the cutter mounting portion 32. Specifically, the connecting bar 312 is slidable in the direction in which the restoring force D of a leaf spring 313 described later acts and in the opposite direction by an external force.

[0041] Further, as shown in FIG. 12, a part 3121 of the periphery of the connecting bar 312 has an arc shape having the same radius of curvature as the radius of curvature of the second through-hole 21, and the part 3121 of the periphery can be in surface contact with the second through-hole 21. Further, the other parts of the connecting bar 312 except for the part 3121 do not contact the inner wall of the second through-hole 21.

[0042] The leaf spring 313 is fixed to both ends of the connecting bar 312 as shown in FIGS. 10 and 11, and the central portion 3131 is supported by the inner wall of the second through-hole 21. As is well known, most leaf springs are formed in an elliptical shape using spring steel, and the spring steel can be bent when pressure is applied to one side, but has the property of returning to its original position through a damping process.

[0043] The cutter mounting portion 32 is coupled to the cutter tilt portion 31 in a slidable state relative to the cutter tilt portion 31.

[0044] Specifically, as shown in FIG. 13, the cutter mounting portion 32 includes a cutter mounting portion main body 321 having a third through hole 3211 into which a connecting bar 312 is inserted. Here, the connecting bar 312 is fixed so as not to rotate relatively within the third through hole 3211. To achieve this, for example, as shown in FIG. 13, other portions of the connecting bar 312 except for a part 3121 thereof are composed of three straight sides that are connected at right angles to each other. And the third through hole 3211 has a rectangular cross section correspondingly.

[0045] On the other hand, as shown in FIG. 8, the cutter tilt portion 31 can further include a cover 315 that is fixed to the opposing surface of the cutter tilt portion 31 while covering the cutter mounting portion main body 321. The cover 315 is fixed to the opposing surface of the cutter tilt portion 31 using a fastener 4 so as not to move relatively. Further, a groove portion 3151 corresponding to the contour of the cutter mounting portion main body 321 is formed on the inner surface of the cover 315. Thus, when the cutter tilt portion 31 tilts relative to the cylinder portion 22, the cover 315 tilts together in conjunction therewith, tilting the cutter mounting portion 32 fixed to the connecting bar 312.

[0046] On the other hand, as shown in FIGS. 8 and 10, in the initial state where the connecting bar 312 is not sliding, the cover 315 and the cutter mounting portion main body 321 are arranged such that a gap S is formed between the upper end P1 of the cutter mounting portion main body 321 and the upper end P2 of the groove portion 3151 of the cover.

[0047] Hereinafter, with reference to FIGS. 10 and 14, the operation of the acetabular cup removal device for artificial hip joints according to an embodiment of the present invention having the above-described configuration will be described.

[0048] When the acetabular cup C is elliptical (a shape cut in half along the minor axis of the ellipse), in order to remove the acetabular cup C from the acetabulum of the pelvis, the cutter part 3 is tilted toward the apex O of the acetabular cup C (see 0° and 30° in Fig. 14). At this time, when the cutter part 3 is tilted at a predetermined angle, for example, about 60°, the cutter 33 may get caught on the outer surface of the acetabular cup C. At this time, as the cutter part 3 continues to tilt further, a force acts to pull the cutter mounting part 32 in the direction in which the leaf spring 313 is compressed within the second through hole 21 due to the contact reaction force between the acetabular cup C and the cutter 33. As a result, the cutter mounting part 32 can slide in the b direction in Fig. 12, the b direction in Fig. 13, and the T direction in Fig. 14. At this time, the gap S between the upper end P1 of the main body part 321 of the cutter mounting part and the upper end P2 of the groove part 3151 of the cover becomes narrower. For reference, Figs. 10 and 13a show the initial state in which no external force for sliding the cutter mounting part 32 is acting.

[0049] Therefore, different from the prior art, the cutter 33 can move smoothly along the surface of the acetabular cup C, and the cutter part (cutter) can tilt up to the apex O of the acetabular cup C. Thus, it becomes possible to easily remove the acetabular cup C from the acetabulum of the pelvis while minimizing bone loss in the patient (see 90° in Fig. 14).

[0050] On the other hand, when the external force acting in the direction in which the leaf spring 313 is compressed is removed, the cutter mounting part 32 is slid back to the initial state within the second through hole 21 by the restoring force D of the leaf spring 313 (see Fig. 10). At this time, the gap S between the upper end P1 of the main body part 321 of the cutter mounting part and the upper end P2 of the groove part 3151 of the cover returns to the initial state and widens again.

[0051] As described above, the preferred embodiments of the present invention have been described in detail. However, the scope of the rights of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present invention described in the following claims are also included in the scope of the rights of the present invention.

Industrial Applicability

[0052] The present invention can be used for a wide acetabular cup removal device for artificial hip joints.

Claims

1. A main shaft that can be attached to a power tool and is rotatable by the driving force of the power tool, and a cutter part that is provided at the front end of the main shaft, can be tilted along the acetabular part where the acetabular cup is implanted, and cuts the acetabular part while rotating by the main shaft, The cutter part includes A cutter tilt part that can be tilted along the acetabular part around a virtual tilt axis, A cutter mounting part that is slidably coupled to the cutter tilt part in a direction approaching or moving away from the virtual tilt axis, and A cutter that is detachably mounted on the cutter mounting part and includes The cutter tilt part includes A first through hole penetrating along the virtual tilt axis, A connecting bar with both ends fixed to the cutter mounting part, and A leaf spring fixed to both ends of the connecting bar and having a central part between the two ends and includes The main shaft includes a cylinder part inserted into the first through hole and having a second through hole formed in its length direction, The connecting bar is slidably located in the second through hole in a direction approaching or moving away from the virtual tilt axis within the second through hole, The central part of the leaf spring is supported by the inner wall of the second through hole, An acetabular cup removal device for artificial hip joints.

2. The second through hole has a circular cross section, The connecting bar has an arc shape with a part of its circumference having the same radius of curvature as the radius of curvature of the second through hole and can be in surface contact with the second through hole. The acetabular cup removal device for artificial hip joints according to Claim 1.

3. The other parts of the connecting bar except the part do not contact the second through hole. The acetabular cup removal device for artificial hip joints according to Claim 2.

4. The cutter mounting portion includes a cutter mounting portion main body having a third through hole into which the connecting bar is inserted, The connecting bar does not rotate relative to the cutter mounting portion main body within the third through hole and is tilted in conjunction with tilting of the cutter mounting portion. The acetabular cup removal device for artificial hip joints according to claim 2.

5. The other portion of the connecting bar has three sides that are connected at right angles to each other, The third through hole has a rectangular cross section. The acetabular cup removal device for artificial hip joints according to claim 4.

6. The cutter tilt portion further includes a cover that is fixed to the opposing surface of the cutter tilt portion while covering the cutter mounting portion main body. The acetabular cup removal device for artificial hip joints according to claim 4.

7. A groove portion corresponding to the contour of the cutter mounting portion main body is formed on the inner surface of the cover, A gap is formed between the upper end of the cutter mounting portion main body and the upper end of the groove portion of the cover. The acetabular cup removal device for artificial hip joints according to claim 6.

8. In an initial state where no external force acts on the leaf spring, the portion of the connecting bar contacts the second through hole, When an external force acts on the leaf spring, the leaf spring is compressed and the portion of the connecting bar is separated from the second through hole. The acetabular cup removal device for artificial hip joints according to claim 2.

9. The cover is fixed to the opposing surface of the cutter tilt portion by a fastener fixed to the connecting bar so as not to move relative to it. The acetabular cup removal device for artificial hip joints according to claim 6.

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