JP2001212153A - Artificial joint-replacing operational instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an artificial joint-replacing operational instrument capable of mounting an acetabular cartridge cup at an affected part without operating an abnormal force at the cup and not obstructing its use by cement adhering. SOLUTION: The artificial joint-replacing operational instrument 1 comprises an acetabular cartridge cup contact means 2 having a contact part contacted with the acetabular cartridge cup for an artificial joint at its lower surface, a cup holding means 3 provided in the means 2 and having a pin 31 movably projected from the lower surface of the means 2 to hold the cup, a main shank 4 fixed at its one end to the means 2, a drive means 5 axially movably provided at the shank 4, and a drive transmitting means for transmitting a drive force for moving the holding means in association with the movement of the drive means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surgical instrument for artificial joint replacement, and more particularly, to a surgical instrument for setting an acetabular cup in artificial joint replacement for osteoarthritis.

[0002]

2. Description of the Related Art Conventionally, in an artificial joint replacement surgical instrument using bone cement, an acetabular cup to be installed is attached to the tip of the surgical instrument, and after filling the bone cement into a pelvic acetabular excavated in a hemispherical shape, The acetabular cup is pressed in and held until the bone cement has hardened to some extent (2-3 minutes).

FIG. 5 shows a conventional example of a surgical instrument. This figure shows a plate-shaped acetabular cup contacting means 72 having a contact portion 71 for contacting with an acetabular cup 80 on the lower surface thereof; A cup holding means 74 having a pin 73 for holding the cup 80 movably protruding from the lower surface of the acetabular cup abutting means 72, a main shaft 75 having one end fixed to the cup holding means 74; A rod 7 having one end fixed to the means 74 and movably provided in the axial direction of the main shaft 75
6 are provided. In the conventional surgical instrument 70 having such a configuration, the rod 76 is attached to the main shaft 75 with respect to FIG.
It is movable in the direction of W1-W2 in the middle. With the movement of the rod 76, the acetabular cup contacting means 72 moves toward and away from the cup holding means 74. As a result, FIG.
As shown in (a), the pin 73 of the cup holding means 74 can be pulled out or retracted from the lower surface of the acetabular cup contact means 72.

In a state where the pin 73 is protruded to the maximum from the acetabular cup contact means 72, the pin 73 is pressed into the corresponding insertion hole 81 of the acetabular cup 80 to hold the acetabular cup 80, Conversely, the surgical instrument 70 has been removed from the acetabular cup 80 by retracting the pin 73.

When removing the surgical instrument 70 from the acetabular cup 80, the acetabular cup contact means 72 presses the acetabular cup means in the direction of W2. Along with this, due to the reaction of this stress, the cup holding means 74 is moved in the direction indicated by X1 in the figure, and at this time, the stress in the X1 direction is applied to the wall surface of the insertion hole 81 of the acetabular cup 80. As a resultant of the stresses in these two directions, a stress was generally generated in the direction indicated by N1 in the figure at the contact portion between the acetabular cup contacting means 72 and the acetabular cup 80. As a result, the acetabular cup contact means 72 was slid in the N1 direction.

[0006]

The surgical instrument 70 for artificial joint replacement has a function of holding the acetabular cup 80 at a predetermined installation position and an angle, and a predetermined installation method when the bone cement hardens to some extent. It is necessary to remove it without applying an inappropriate force that changes the position or angle.

However, as described above, when the conventional surgical instrument 70 is detached from the acetabular cup 80, the contact portion between the acetabular cup abutting means 72 and the acetabular cup 80 is set at N1 in FIG. Stress was generated in the direction shown, and as a result, there was a risk that the installation position of the acetabular cup 80 would change or that the installation angle would change due to the rotation of the acetabular cup 80.

Further, when the surgical instrument 70 is removed from the acetabular cup 80, half-third cement leaks from the acetabular cup,
There was a case where it got into between the acetabular cup contacting means 72 and the cup holding means 74. In such a case, if the cement is not completely removed, a problem may occur such that the two adhere to each other.

The present invention has been made to solve such a problem. An object of the present invention is to provide an artificial joint replacement surgical instrument that can attach an acetabular cup to an affected area without exerting an abnormal force on the acetabular cup and that does not hinder use due to cement adhesion. Things.

[0010]

The present invention has the following configuration to achieve the above object. That is, the invention of claim 1 provides an acetabular cup abutting means having an abutting portion for abutting on the acetabular cup for an artificial joint, and an acetabular cup abutment provided in the acetabular cup abutting means. A cup holding means in which a pin for holding a cup is movably protruded from a lower surface of the acetabular cup contact means, a main shaft having one end fixed to the acetabular cup contact means, and an axial direction of the main shaft. An artificial joint replacement surgical instrument comprising a freely provided driving means and a drive transmitting means for transmitting a driving force for moving the cup holding means with the movement of the driving means.

According to the first aspect of the present invention, the acetabular cup contact means and the main shaft are fixed, and the cup holding means is provided in the acetabular cup contact means. May be configured not to move relative to the main shaft. That is, when removing the surgical instrument from the acetabular cup, the pin enters into the lower surface of the acetabular cup without moving the acetabular cup abutting means. The contact state can be maintained. Therefore, there is no need to worry about positional deviation and angular deviation of the installation.

Further, as described above, since the cup holding means is provided in the acetabular cup contact means, cement does not adhere to the inside of the acetabular cup contact means. There is no problem in using the outer periphery of the contact means at all. Further, the cement adhered to the outer periphery of the acetabular cup contact means can be easily removed.

According to a second aspect of the present invention, the drive transmitting means is further limited. The drive transmitting means is slidably provided in the acetabular cup contact means.
One end portion has a cam portion that contacts the cup holding means, and the pin portion of the cup holding means is moved from the holding position of the acetabular cup to the non-holding position with the sliding of the drive transmission means. And

According to the second aspect of the present invention, since the drive transmission mechanism in the acetabular cup contact means can be simplified, the operation of the first aspect can be achieved without increasing the size of the surgical instrument. Can be better achieved. In addition, since the acetabular cup contact means can have a sealed structure, the adhered cement can be easily cleaned.

[0015] Next, the invention according to claim 3 further restricts the driving means, wherein the driving means is slidably fitted in the main shaft, one end of which is provided in the cup holding means. The other end of the main shaft comes into contact with a pressing means provided at the other end of the main shaft, and the pressing force of the pressing means is transmitted to the driving transmitting means as a sliding force of the driving transmitting means. And

According to the third aspect of the present invention, the driving force from the pressing means can be efficiently transmitted to the cup holding means, and the operation of the surgical instrument can be smoothly performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an artificial joint replacement surgical instrument (hereinafter referred to as a surgical instrument) 1 according to the present invention. This surgical instrument includes acetabular cup contact means (hereinafter abbreviated as cup contact means) 2, cup holding means 3, main shaft 4, rod 5 as drive means, and cam 6 as drive transmission means. Is done.

The cup contacting means 2 forms a substantially cylindrical block. The lower surface of the block body is provided with a planar contact portion 21 that contacts the acetabular cup. A removable cover 23 is mounted on the upper surface, and covers the upper side and the lateral side of the internal space 22 described below.

Referring to FIG. 2, the shape of the cup abutting means 2 will be further described. As shown in FIG. 2 with the cover 23 removed, an inner space 22 that is a groove-like space is formed on the upper surface of the cup abutting means 2.
A pair of pin insertion holes 25, 25 penetrating through the contact portion 21 are provided on the bottom surface of the internal space 22.

As shown in FIG. 1 (c), in the internal space 22 of the cup abutting means 2, a cup holding means 3 having a pin 31 on its lower surface, and slidably engaged with the cup holding means 3. And a cam 6 provided with a cam portion 61 which is provided.

The cup holding means 3 has a pair of pins 31 on the lower surface side. In FIG. 1, one pin 31
Although only the cup holding means 3 is shown, the cup holding means 3 includes a pair of pins 31, 31 at positions corresponding to the pair of pin insertion holes 25, 25 of the cup contact means 2 shown in FIG.

The pins 31, 31 are movably protruded from the lower surface of the contact portion 21 of the cup contact means 2 through the pin insertion holes 25, 25 provided in the cup contact means 2.

The shape of the cup holding means 3 will be described with reference to FIG. The cup holding means 3 has a large-diameter pressure-receiving projection 33 on the upper surface of a substantially rectangular plate-shaped base portion 32.
On the lower surface of the base portion 32, a pair of pins 31 are provided on both short pieces, and a pair of cam engaging recesses 36 are provided on one corner of the long piece of the lower surface. Further, a hemispherical recess 35 is provided on the upper surface of the pressure receiving projection 33.

The cup holding means 3 has a pressure receiving projection 3
As shown in FIG. 1C, 3 is inserted through a through hole 24 formed in the cover 23 and protrudes from the cover 23.
Then, the tip of a pressing rod (not shown) is applied to the depression 35 provided on the upper surface of the pressure receiving projection 33, and the rod allows the acetabular cup to be pushed in the vertical direction.

The pins 31, 31 of the cup holding means 3
Protrudes movably from the contact portion 21 of the cup contact means 2 through the pin insertion holes 25, 25 of the cup contact means 2.

The pins 31, 31 are pressed into pin insertion holes (see 81 in FIG. 6) provided at corresponding positions of the acetabular cup, whereby the surgical instrument 1 holds the acetabular cup. .

The shape of the cam 6 will be described with reference to FIG. The cam 6 includes a pair of cam portions 61 on one wide surface of a substantially rectangular plate-shaped base portion 62. The cam portion 61 has a shape as if a quadrangular prism is diagonally divided into two, and its engagement surface 63 is tapered. The engaging surface 63 is engaged with the cam engaging portion 36 of the cup holding means 3 described above, and operates the cup holding means 3 as the cam 6 slides.

The engagement surface 63 of the cam 6 (see FIG. 3)
It is preferable to have an inclination angle θ of 30 ° to 60 °.
By setting the inclination angle θ ° of the engagement surface 63 within the above range,
A small space is not required, and the sliding contact between the cam 6 and the cup holding means 3 becomes smooth. As a result, the surgical instrument 1 tends to be easily operated with a small force. On the other hand, when the inclination angle θ ° of the engagement surface 63 is less than 30 °, the size of the cam 6 tends to be large, and the surgical instrument 1 tends to be large. There is a fear that the sliding contact stress between the cam 6 and the cup holding means 3 increases, and it becomes difficult to operate the surgical instrument 1.

The cam engaging recess 36 and the cam portion 61 are provided at left and right symmetrical positions of the base portions 32 and 62, respectively, so that the left and right sides of the cup holding means 3 do not tilt up and down. This is so that they can move. The position and interval may be determined in consideration of this. Also, as long as this point is taken into consideration, the number of the cam engaging concave portions 36 and the cam portions 61 may be one or three or more.

As described above, the drive transmission mechanism in the acetabular cup contact means 2 is simple. Therefore, the surgical instrument 1 has an advantage that its size can be reduced.

Next, as shown in FIG. 1, a cylindrical main shaft 4 is fixed to the acetabular cup contact means 2. The acetabular cup contacting means 2 is lowered forward by about 45 ° with respect to a direction perpendicular to the main shaft 4. Thereby, workability when fixing the acetabular cup with the surgical instrument 1 is improved.

The internal space 41 of the main shaft 4 and the internal space 41 of the cup
The rod 5 is provided so as to be movable in the axial direction so that the second member 2 penetrates. The rod 5 has a distal end 51 cut substantially parallel to the contact portion 21 of the cup contact means 2.
Having. The distal end portion 51 is in contact with the cam 6 and operates the cam 6 with the movement of the rod 5.

The rod 5 has its tip cut substantially parallel to the abutting portion 21 of the cup abutting means 2 so that the rod 5 can have a large moving width even in a narrow space.
Accordingly, the movement width of the pin 22 can be increased.

The tip 52 of the rod 5 has a radius of curvature R
= 0.3 to 1 mm. This state of the art 5
By setting 2 to the above-mentioned radius of curvature, the cam 6 can be easily brought into sliding contact with the cam 6 smoothly without damaging the surface thereof. If the radius of curvature R is less than 0.3 mm, the tip 52 becomes sharp and damages the surface of the cam 6. As a result, the front end 52 may be caught by a scratch on the surface of the cam 6 and may be difficult to use. On the other hand, when the radius of curvature R is larger than 1 mm, the slip of the tip end 52 with respect to the cam 6 may be deteriorated.

The cam 6 has an engagement surface 63 which is in sliding contact with the cup holding member 3 and a back surface 64 which is in sliding contact with the rod 5 which is subjected to buffing or the like, and these surfaces have an average surface roughness Ra = 0.0.
It is preferably 8 μm or less. By setting the average surface roughness of these surfaces within the above range, the sliding contact between the members of the rod 5, the cam 6, and the cup holding means 3 is easy to be smooth, and the surgical instrument 1 can be operated with a small force. Tend. On the other hand, the average surface roughness Ra is 0.8 μm.
If it is larger than m, the sliding contact between the members may not be smooth.

Further, the cup contact means 2 of the main shaft 4
As shown in FIG. 1A, a substantially L-shaped handle 7 is fixed to the opposite end. The handle 7 can be gripped by the operator. In the vicinity of a fixed portion of the handle 7 with the main shaft 4, a lever-shaped pressing means 8 is attached rotatably about a shaft 81.

One end of the pressing means 8 is in contact with the end of the rod 5 to which the pressure receiving cap 9 is fixed. An elastic body 10 such as a coil spring is fitted around the rod 5 adjacent to the pressure receiving cap 9. The elastic body 10 constantly urges the rod 5 toward the handle 7.

Next, the operation of the surgical instrument 1 having such a configuration will be described.

The operator hooks the pressing means 8 on the forefinger of the hand holding the handle 7 and pulls one end of the pressing means 8 with the forefinger to the position shown by the dotted line as if to trigger the gun. With this movement, the other end of the pressing means 8 is moved to the position shown by the dotted line. As a result, the rod 5 can be moved in the direction of the cup contact means 2. On the other hand,
When this state is released, the pressing means returns to the position indicated by the solid line by the elastic body 10. Accordingly, the rod 5 is moved in the direction of the handle 7.

That is, the surgical instrument 1 can move the rod 5 in the ZZ direction shown in FIG. 1C by operating the pressing means.

With the movement of the rod 5 in the ZZ direction,
The cam 6 is slid in the X-X line direction.
With the sliding in the -X direction, the cup holding means 3 and the pins 31 provided therein are moved in the YY direction.

Next, as the pin 31 moves in the YY direction, the pin 31 is moved in and out of the lower surface of the contact portion 21 of the cup contact means 2, and the pin 31 holds the acetabular cup. It is moved between a position (position indicated by a solid line) and a non-holding position (position indicated by a dotted line).

As described above, the surgical instrument 1 can hold the acetabular cup or can be removed from the acetabular cup by operating the pressing means 8.

According to the surgical instrument 1 having such a configuration, the cup contact means 2 and the main shaft 4 are fixed, and the cup holding means 3
Is provided in the cup abutting means 2 so that the cup abutting means 2
Is configured not to move with respect to the acetabular cup.

That is, when removing the surgical instrument 1 from the acetabular cup, the pin 31 enters into the lower surface of the surgical instrument 1 when the cup contact means 2 is moved. The contact state can be maintained without changing. Therefore, there is no need to worry about the positional deviation and the angular deviation of the setting of the acetabular cup.

As described above, since the cup holding means 3 is provided in the cup abutting means 2 in a sealed state, the cement does not adhere to the internal space of the cup abutting means 2. Therefore, there is no problem in using the cement on the outer periphery of the cup contact means 2 at all. Further, the cement adhering to the outer periphery of the cup contact means 2 can be easily removed.

Further, according to the driving force transmission mechanism of the surgical instrument 1 as described above, the driving force from the pressing means 8 can be efficiently transmitted to the cup holding means 3, and the operation of the surgical instrument 1 can be smoothly performed. It has the advantage of being able to.

As a material of each member constituting the surgical instrument 1, a metal such as stainless steel or titanium, a hard synthetic resin such as polyethylene, or a ceramic such as alumina can be appropriately used. Particularly, the rod 5 and the cam 6 having the sliding portion are preferably made of ceramics having high hardness, such as stainless steel and alumina. Cup holding means 3
Although a sliding portion is provided, a large bending strength is required at the portion of the pin 31. Therefore, stainless steel is more preferable than ceramics as a material.

Next, another embodiment of the surgical instrument of the present invention will be described with reference to the explanatory view of FIG.

This surgical instrument 10 differs from the surgical instrument 1 of the above-described embodiment only in the form of the drive transmission means. As shown in FIG. 1, the swing bar 12 as a drive transmission unit is a bar-shaped member that swings around a fixed fulcrum 13. The swing rod 12 has slit holes 12 at both ends. The rod 5 and the cup holding means 3 are provided with a shaft 14 through which these slit holes 12 are inserted. This shaft 14 is arranged with respect to the slit hole 12.
It is movable along the longitudinal direction of the slit.

In this surgical instrument 10, the rocking means 12 is rocked about the fulcrum 13 with the movement of the rod 5. Then, with the swing of the swing means 12, the cup holding means 3 and its pin 31 are moved up and down. At this time, the shaft 14 can move within the slit hole 12.

In such a surgical instrument 10, the size of the surgical instrument can be reduced because the drive transmission mechanism in the cup contact means can be reduced in size.

It should be noted that the present invention is not limited to the above-described embodiment, and can be of any form without departing from the object of the present invention.

[0055]

According to the first aspect of the present invention, as described above,
Since the acetabular cup contact means and the main shaft are fixed and the cup holding means is provided in the acetabular cup contact means, the surgical instrument can be removed without changing the positional relationship with respect to the acetabular cup. Therefore, there is no need to worry about positional deviation and angular deviation of the installation.

Further, since the cement does not adhere to the internal space of the acetabular cup contact means, there is no problem in use of the cement on the outer periphery of the acetabular cup contact means. The cement adhering to the can be easily removed.

According to the second aspect of the present invention, since the drive transmission mechanism in the acetabular cup contact means is simple, the size of the surgical instrument can be reduced. As a result, handling is easy for the surgeon.

Further, according to the third aspect of the present invention, since the driving force from the pressing means can be efficiently transmitted to the cup holding means, the operation of the surgical instrument can be smoothly performed.

[Brief description of the drawings]

FIG. 1 shows a surgical instrument of the present invention. (A) is a partially cutaway side view, (b) is a view from arrow A of (a), (c) is B of (b).
FIG. 4 is a cross-sectional view taken along line B.

FIG. 2 shows a cup contact means and a main shaft which constitute the surgical instrument of FIG. 1; (A) is a side view, (b) is a view on arrow C of (a). FIG. 4 is a view of a state in which a cover constituting a cup abutting means is removed.

FIG. 3 is a perspective view of cup holding means constituting the surgical instrument of FIG. 1;

FIG. 4 is a perspective view of a cam as a drive transmission unit included in the surgical instrument of FIG.

FIG. 5 is a schematic explanatory view showing a surgical instrument according to another embodiment of the present invention.

FIG. 6 shows a conventional surgical instrument and acetabular cup. (A) is a side view, (b) is a view of the surgical instrument viewed from below.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 (artificial joint replacement) surgical instrument 2 (acetabular) cup contact means 3 cup holding means 4 main shaft 5 rod (drive means) 6 cam (drive transmission means) 61 cam section 8 pressing means

Claims (3)

[Claims] 1. An acetabular cup contacting means having a contact portion on its lower surface for contacting with an artificial joint acetabular cup, and provided in the acetabular cup contacting means for holding the artificial joint acetabular cup. Cup holding means having a pin to be movably protruded from the lower surface of the acetabular cup abutting means, a main shaft having one end fixed to the acetabular cup abutting means, and movably provided in the axial direction of the main shaft. An artificial joint replacement surgical instrument comprising: a driving unit provided with a drive unit; and a drive transmitting unit configured to transmit a driving force for moving the cup holding unit in accordance with the movement of the driving unit. 2. The drive transmission means is slidably provided in the acetabular cup contact means, and has a cam portion having one end contacting the cup holding means. The artificial joint replacement surgical instrument according to claim 1, wherein the pin of the cup holding means is moved from the holding position of the acetabular cup to the non-holding position with the movement. 3. The drive means is slidably fitted in the main shaft, one end of which is in contact with the drive transmission means provided in the cup holding means, and the other end of the main shaft is in contact with the drive transmission means. 3. The artificial joint replacement surgical instrument according to claim 2, wherein the abutment means is in contact with the pressing means provided on the other end side, and transmits the pressing force of the pressing means to the drive transmitting means as a sliding force of the drive transmitting means.