JP2020156977A - Cup placing device - Google Patents

Abstract

To provide a cup placing device that can strike a balance between a screw-type mounting structure and prevention of relative rotation of a cup to the cup placing device.SOLUTION: A cup placing device 1 for use in placing a hemispherical cup 7 of a prosthetic hip joint in an acetabular cup comprises a rod-like placing device body 2, and a tip end attachment 3 with the cup 7 mounted thereon and capable of being attached and detached to/from a tip end of the placing device body 2. A screw hole is provided in a center of the cup 7, and a polygonal recess around the screw hole is formed in an inside surface of the cup 7. The tip end attachment 3 comprises a rod 4 having a screw shaft screwed in the screw hole of the cup 7, and a housing 5 being a cylindrical housing 5 which is inserted to the rod 4 and fitted in the recess of the cup 7. The housing 5 is inserted in a non-rotatable manner, into an insert hole 23 provided at a tip end of the placing device body 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cup driving device used when driving a hemispherical cup of an artificial hip joint into a acetabulum.

For the hip prosthesis, a hemispherical cup that is slightly larger than the patient's acetabulum (the pelvic depression into which the femoral head fits, also known as the acetabulum) is selected and the cup is press-fitted into the acetabulum. To. A cup driving device is used to perform this press-fitting (see, for example, Patent Document 1).

The cup driving device is a rod-shaped device, and a cup is attached to the tip of the cup driving device. The cup driving device is operated so that the cup reaches a position where it can be press-fitted into the mortar, and in that state, the base end of the cup driving device is hit with a hammer or the like, so that the cup is driven into the mortar and the mortar. It is press-fitted into the lid.

JP-A-2018-33793

Generally, since the cup is provided with a through hole for a screw for fixing to the acetabulum, there is a desire to adjust the relative rotation position of the cup with respect to the acetabulum. From this point of view, a square-shaped depression is formed in the center of the inner surface of the cup, and the cup may be non-rotatably attached to the tip of the cup driving device by using this depression.

By the way, as a structure for attaching the cup to the cup driving device, there is also a structure in which a screw shaft provided at the tip of the cup driving device is screwed into a screw hole provided in the center of the cup. For a cup driving device having such a screw type mounting structure, it is difficult to adopt a configuration for preventing the relative rotation of the cup with respect to the above-mentioned cup driving device.

Therefore, an object of the present invention is to provide a cup driving device capable of achieving both a screw type mounting structure and prevention of relative rotation of the cup with respect to the cup driving device.

In order to solve the above problems, the cup driving device of the present invention is a cup driving device used when driving a hemispherical cup of an artificial hip joint into the acetabulum, and has a rod-shaped driving device main body and a rod-shaped driving device body. A tip attachment that can be attached to and detached from the tip of the driving device body to which the cup is attached is provided, a screw hole is provided in the center of the cup, and the screw hole is provided on the inner surface of the cup. A polygonal recess is formed at the center, and the tip attachment is a rod having a screw shaft screwed into the screw hole and a tubular housing inserted into the rod, and the recess of the cup. It is characterized in that the housing is non-rotatably inserted into an insertion hole provided at the tip of the driving device main body.

According to the above configuration, since the housing of the tip attachment is inserted through the rod, the rod can be rotated with the housing fitted in the polygonal recess of the cup. As a result, the screw shaft of the rod can be screwed into the screw hole of the cup to attach the cup to the tip attachment. Since the tip attachment is removable from the driving device main body, if the cup is attached to the tip attachment with the tip attachment removed from the driving device main body, the attachment work can be easily performed. Furthermore, since the housing of the tip attachment is non-rotatably inserted into the insertion hole of the driving device body, if the tip attachment is attached to the tip of the driving device body, the cup can be operated with respect to the acetabulum by operating the cup driving device. The relative rotation position can be adjusted.

The rod has a head that abuts on the end surface of the housing and an intermediate shaft that is smaller in diameter than the screw shaft and is interposed between the head and the screw shaft, and is provided on the inner peripheral surface of the housing. , A screw portion that can be screwed with the screw shaft and is located around the intermediate shaft may be provided. According to this configuration, since the threaded portion of the housing functions as a rod stopper, the housing can hold the rod with a simple structure.

A holding groove for holding the engaging ring may be formed on the inner peripheral surface of the insertion hole, and an engaging groove into which the engaging ring may be fitted may be formed on the outer peripheral surface of the housing. .. According to this configuration, the tip attachment can be attached to the driving device main body only by inserting the tip attachment into the insertion hole of the driving device main body.

For example, at least one protrusion may be formed on the outer peripheral surface of the housing, and a rotation restricting groove into which the protrusion may be fitted may be formed on the inner peripheral surface of the insertion hole.

According to the present invention, it is possible to achieve both a screw-type mounting structure and prevention of relative rotation of the cup with respect to the cup driving device.

It is a side view of the cup driving device which concerns on one Embodiment of this invention. It is sectional drawing of the tip part of the cup driving device shown in FIG. It is a perspective view which showed a part of the tip of the driving device main body in the cross section. (A) is a perspective view of the tip attachment viewed from the front, and (b) is a perspective view of the tip attachment viewed from the rear. It is a perspective view which looked at the cup from the inside.

FIG. 1 shows a cup driving device 1 according to an embodiment of the present invention. The cup driving device 1 is used when driving the hemispherical cup 7 of the artificial hip joint into the acetabulum (not shown).

Specifically, the cup driving device 1 includes a rod-shaped driving device main body 2 and a tip attachment 3 that can be attached to and detached from the tip of the driving device main body 2. A cup 7 is attached to the tip attachment 3.

The driving device main body 2 includes a grip portion 22 gripped by a doctor or the like and a pole portion 21 extending from the grip portion 22. The tip of the pole portion 21 is inserted into the patient's body. In this embodiment, the pole portion 21 is curved in a bow shape so as to easily avoid interference with muscle tissue in the patient's body. However, the pole portion 21 may be linear.

The tip of the pole portion 21 is also the tip of the driving device main body 2, and the end of the grip portion 22 opposite to the pole portion 21 is the base end of the driving device main body 2 that is hit with a hammer or the like.

The tip of the pole portion 21 is located on an extension of the center line of the grip portion 22. As shown in FIGS. 2 and 3, the tip of the pole portion 21 is provided with an insertion hole 23 into which the tip attachment 3 is inserted. The insertion hole 23 is a hole centered on an extension line of the center line of the grip portion 22, and penetrates the tip of the pole portion 21 along the extension line of the center line of the grip portion 22.

In the following, for convenience of explanation, the direction along the extension line of the center line of the grip portion 22 may be referred to as the front-rear direction (the pole portion 21 side is the front and the grip portion 22 side is the rear).

As shown in FIG. 2, the tip attachment 3 includes a rod 4 and a tubular housing 5 inserted through the rod 4. The housing 5 has a flange portion 52 that abuts on the tip surface of the pole portion 21, a fitting portion 51 that projects forward from the flange portion 52, and a tubular portion 53 that projects rearward from the flange portion 52.

As shown in FIG. 5, the cup 7 is provided with a screw hole 71 in the center, and a plurality of through holes 73 are provided around the screw hole 71. The through hole 73 is a hole for a screw for fixing the cup 7 to the acetabulum. Further, on the inner peripheral surface of the cup 7, a polygonal recess 72 centered on the screw hole 71 is formed.

In the present embodiment, the shape of the recess 72 is a quadrangle (square in the example). However, the shape of the recess 72 may be another polygon such as a hexagon.

The fitting portion 51 of the housing 5 described above is a portion that fits into the recess 72 of the cup 7, and is slightly smaller than the contour of the recess 72 as shown in FIGS. 2 and 4 (a) and 4 (b). Has a contour.

The tubular portion 53 of the housing 5 is a portion to be inserted into the insertion hole 23. As shown in FIG. 3, a holding groove 27 continuous in the circumferential direction is formed on the inner peripheral surface of the insertion hole 23 at a position slightly recessed from the tip surface of the pole portion 21. As shown in FIG. 2, the engaging ring 6 is held in the holding groove 27.

On the other hand, as shown in FIGS. 4A and 4B, an engaging groove 55 continuous in the circumferential direction is formed on the outer peripheral surface of the tubular portion 53. When the tubular portion 53 is inserted into the insertion hole 23, the engaging ring 6 held in the holding groove 27 fits into the engaging groove 55. That is, the tip attachment 3 can be attached to the driving device main body 2 simply by inserting the tip attachment 3 into the insertion hole 23 of the driving device main body 2. On the other hand, when removing the tip attachment 3 from the driving device main body 2, it is only necessary to pull out the tip attachment 3 from the insertion hole 23.

Further, at least one protrusion 54 is formed on the outer peripheral surface of the tubular portion 53. In this embodiment, two protrusions 54 are provided at 180 degree intervals, and each protrusion 54 extends in the axial direction of the tubular portion 53.

On the other hand, two rotation restricting grooves 26 are formed on the inner peripheral surface of the insertion hole 23. Each rotation control groove 26 extends in the axial direction of the tubular portion 53 and opens to the tip surface of the pole portion 21. When the tubular portion 53 is inserted into the insertion hole 23, the protrusion 54 fits into the corresponding rotation restricting groove 26. As a result, the relative rotation of the housing 5 with respect to the driving device main body 2 is prevented. That is, the housing 5 is non-rotatably inserted into the insertion hole 23.

The rod 4 of the tip attachment 3 has a screw shaft 43 screwed into the screw hole 71 of the cup 7, a head 41 abutting on the rear end surface of the housing 5, and an intermediate shaft interposed between the head 41 and the screw shaft 43. It has 42. The total length of the intermediate shaft 42 and the screw shaft 43 is longer than the length of the housing 5. Therefore, the tip of the screw shaft 43 is located in front of the front end surface of the housing 5. Then, the cup 7 is pressed against the front end surface of the housing 5 by screwing the screw shaft 43 into the screw hole 71 of the cup 7.

The intermediate shaft 42 has a smaller diameter than the screw shaft 43. The front portion of the inner peripheral surface of the housing 5 is a smooth cylindrical surface, but a screw portion 56 is provided on the rear portion of the inner peripheral surface. That is, the screw portion 56 is located around the intermediate shaft 42.

The screw portion 56 can be screwed with the screw shaft 43 of the rod 4. In other words, the nominal diameter of the screw portion 56 and the nominal diameter of the screw shaft 43 are the same. Therefore, when the rod 4 is inserted into the housing 5, if the screw shaft 43 is screwed into the screw portion 56 and the rod 4 is rotated in one direction, the screw shaft 43 passes through the screw portion 56. With this configuration, since the screw portion 56 functions as a stopper for the rod 4, the rod 4 can be held by the housing 5 with a simple structure. Further, when cleaning the tip attachment 3, the rod 4 can be pulled out from the housing 5 by rotating the rod 4 in the opposite direction while screwing the screw shaft 43 into the screw portion 56.

The head 41 is provided with a hexagonal hole 44 for engaging a tool. As shown in FIG. 1, the pole portion 21 is curved in a bow shape to have an offset portion between the front inclined portion and the rear inclined portion, and a through hole 25 for inserting a tool is provided in this offset portion. Has been done. Further, a notch 24 is also formed on the front inclined portion on the line connecting the hexagonal hole 44 and the through hole 25.

As described above, in the cup driving device 1 of the present embodiment, since the housing 5 of the tip attachment 3 is inserted into the rod 4, the rod 4 is inserted in the state where the housing 5 is fitted into the recess 72 of the cup 7. Can be rotated. As a result, the screw shaft 43 of the rod 4 can be screwed into the screw hole 71 of the cup 7 to attach the cup 7 to the tip attachment 3.

Further, since the tip attachment 3 is removable from the driving device main body 2, if the cup 7 is attached to the tip attachment 3 with the tip attachment 3 removed from the driving device main body 2, the attachment work is easy. Can be done. Further, since the housing 5 of the tip attachment 3 is non-rotatably inserted into the insertion hole 23 of the driving device main body 2, if the tip attachment 3 is attached to the tip of the driving device main body 2, the cup driving device 1 can be inserted. The relative rotation position of the cup 7 with respect to the acetabulum can be adjusted by operation.

(Modification example)
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, in the above embodiment, the housing 5 is non-rotatably inserted into the insertion hole 23 due to the fitting of the protrusion 54 into the rotation restriction groove 26, but the front portion of the insertion hole 23 and the tubular portion 53 of the housing 5 are inserted. Due to the polygonal shape, the housing 5 may be non-rotatably inserted into the insertion hole 23.

1 Cup driving device 2 Driving device body 23 Insertion hole 26 Rotation control groove 27 Holding groove 3 Tip attachment 4 Rod 41 Head 42 Intermediate shaft 43 Screw shaft 5 Housing 54 Protrusion 55 Engagement groove 56 Screw part 6 Engagement ring 7 Cup 71 Screw hole 72 Indentation

Claims (4)

A cup driving device used to drive a hemispherical cup of an artificial hip joint into the acetabulum.
With the rod-shaped driving device body
A tip attachment that can be attached to and detached from the tip of the driving device body to which the cup is attached is provided.
A screw hole is provided in the center of the cup, and a polygonal recess centered on the screw hole is formed on the inner surface of the cup.
The tip attachment includes a rod having a screw shaft screwed into the screw hole, and a tubular housing inserted into the rod that fits into the recess of the cup.
A cup driving device in which the housing is non-rotatably inserted into an insertion hole provided at the tip of the driving device body. The rod has a head that abuts on the end face of the housing, and an intermediate shaft that is smaller in diameter than the screw shaft and is interposed between the head and the screw shaft.
The cup driving device according to claim 1, wherein a screw portion screwable with the screw shaft and located around the intermediate shaft is provided on the inner peripheral surface of the housing. A holding groove for holding the engagement ring is formed on the inner peripheral surface of the insertion hole.
The cup driving device according to claim 1 or 2, wherein an engaging groove into which the engaging ring is fitted is formed on the outer peripheral surface of the housing. At least one protrusion is formed on the outer peripheral surface of the housing.
The cup driving device according to any one of claims 1 to 3, wherein a rotation restricting groove into which the protrusion is fitted is formed on the inner peripheral surface of the insertion hole.

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