JP7750240B2 - Radius fixation plate - Google Patents

Description

The present invention relates to a resin radius fixation plate that is fixed to the radius with fixation screws.

When the radius is fractured, a radius fixation plate is known that straddles the fractured portion to fix the radius, instead of a splint (i.e., a splint) or a plaster or FRP cast, in order to fix the fractured portion of the radius.

When the radius fixation plate is fixed to the radius, a plurality of fixation screws are fastened to the radius.

Conventionally, a thin metal plate such as titanium or its alloy, which is strong, lightweight, and highly biosafe, has been used as a radius fixation plate.

However, metal plates do not allow X-rays to pass through, which poses a problem in that it is not possible to grasp the condition of the fractured area covered by the radius fixation plate.

Therefore, in recent years, a thin resin radius fixation plate has been developed instead of a metal plate (see, for example, Patent Document 1).

Patent Publication No. 2016-016168

After a radial fixation plate is surgically fixed to the arm's radius with fixation screws, the positional relationship between the radial fixation plate and the fractured part of the radius must be examined by X-ray after the surgery. If the radial fixation plate is made of resin, X-rays pass through the resin plate, making it impossible to determine the position of the plate. Therefore, attempts have been made to place metal marker wires around the outer periphery of the plate.

However, if a large volume of wire-shaped marker (i.e., marker wire) is placed at the end of the radial fixation plate, the carbon fiber at the end of the radial fixation plate is reduced by the amount of the marker wire. This reduced amount of carbon fiber reduces the strength of the portion of the end of the radial fixation plate where the marker wire is placed, and fracture of the radial fixation plate begins from the portion with low strength, making it impossible to place a metal marker wire on the radial fixation plate.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a radius fixation plate whose position and orientation can be accurately confirmed after surgery based on the position of a metal marker.

To achieve the above object, according to one aspect of the present invention, there is provided a radial fixation plate that is implantable in an arm and is fixed to a radius, the radial fixation plate having a distal region and a proximal region,
the distal region is a region of the radial fixation plate that includes a curved portion formed by curving a surface of the radial fixation plate facing the radius in a distal direction and is located distal to the curved portion, and the proximal region is a region of the radial fixation plate that is located proximal to the distal region,
a first metallic marker disposed at the distal end and the ulnar end of the distal region;
a second marker made of metal and arranged apart from the first marker ;
The distal region and the proximal region are made of resin .
A radial fixation plate is provided.

According to the above aspect of the present invention, a first metal marker is placed at the distal end and ulnar end of the distal region, and a second metal marker is placed away from the first marker. With this configuration, the position and orientation of the radius fixation plate implanted in the arm can be accurately estimated after surgery based on the positions of at least two metal markers.

These and other objects and features of the present invention will become apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a transparent perspective view showing a state in which a radial fixation plate is fixed to a radius with fixation screws in a radial fixation plate fixation system according to an embodiment of the present invention. Plan view in the state of FIG. 1A A partial cross-sectional view showing the fixation screw being inserted through the guide block and the radial fixation plate using a radial fixation plate fixation screw tool and tightened. An explanatory diagram showing the positional relationship between the radial fixation plate and the distal radioulnar joint. Diagram of the distal radioulnar joint Illustration of the effect of wrist pronation and supination on distal radioulnar joint movement FIG. 10 is an enlarged perspective view showing the location of a first marker on the distal region of the radial fixation plate; FIG. 10 is a perspective side view showing the positions of a first marker and a second marker of a radial fixation plate; FIG. 10 is a perspective side view showing the position of a second marker of a radius fixation plate according to a modification of the embodiment; FIG. 10 is a perspective side view illustrating the position of a second marker on a radial fixation plate according to another modification of the embodiment.

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

As shown in FIGS. 1A and 1B, a radius fixation plate 2 according to an embodiment of the present invention is fixed to a radius 3 with a plurality of metal fixation screws 4.

The radius fixation plate 2 is fixed to the radius 3 across the fractured portion 3a of the radius 3. At this time, to facilitate the operation of rotating and tightening the fixation screws 4 with the radius fixation plate fixation screw tool 1, a guide block 5 having a similar external shape to the radius fixation plate 2 is placed on top of the radius fixation plate 2, as shown in Figure 2. The radius fixation plate guide block 5 is a member that guides the fixation screws 4 when the radius fixation plate 2 is fixed to the radius 3 with the fixation screws 4.

After being placed in this manner, during surgery to implant the radius fixation plate 2 in the arm, the guide block 5 and radius fixation plate 2 are placed on the radius 3, and the screw guide holes 5d of the guide block 5 are used to insert the fixation screws 4 in a specified direction while guiding them in cooperation with pilot holes pre-formed in the radius 3, for example, while the screw tightening operation is performed on the radius 3. After the radius fixation plate 2 is fixed to the radius 3, the guide block 5 is removed from the radius fixation plate 2, leaving only the radius fixation plate 2 on the radius 3.

1A, the fractured portion 3a of the radius 3 is divided into a radius body 3b and a fractured fragment 3c, with the fractured portion 3a as the boundary. The radius body 3b and the fractured fragment 3c may be completely separated or may be partially connected.

The radius fixation plate 2 is placed on the radius 3 so that the fractured fragment 3c is fixed in a state where it is normally connected to the radius body 3b.

1A and 1B, the radius fixation plate 2 has a T-shaped plate member made up of a wide distal region (or distal portion) 2a and a proximal region (or proximal portion) 2b extending from the distal region 2a. In this specification, the "proximal region" refers to a region of the radius fixation plate 2 that is closer to the heart, and the "distal region" refers to a region of the radius fixation plate 2 that is farther from the heart than the proximal region.

The distal region 2a is fixed to the fracture fragments 3c with a plurality of fixation screws 4, and the proximal region 2b is fixed to the radius body 3b with a plurality of fixation screws 4 so that the radius fixation plate 2 straddles the fracture fragments 3a and the fracture fragments 3c are normally connected to the radius body 3b. As an example, when the radius fixation plate 2 is T-shaped as shown in Figure 1B, the relatively wider region can be the distal region 2a and the relatively narrower region can be the proximal region 2b, but this is not limiting.

The radius fixation plate 2 is integrally formed by stacking and fixing a plurality of sheets (not shown) having a thickness N in the thickness direction.

The material of the radius fixation plate 2 is, for example, a synthetic resin mixed with long carbon fibers, such as a thermoplastic resin mixed with long carbon fibers, or a composite material thereof. Examples of thermoplastic resins include PEEK (polyetheretherketone) and polyetherimide. A specific example of the material of the radius fixation plate 2 is carbon fiber reinforced polyetheretherketone (CFRPEEK). Other possible examples of fiber and resin combinations include glass fiber, metal fiber, polyamide fiber, or carbon fiber, and epoxy resin, PEEK resin, or polyetherimide resin.

The radius fixation plate 2 has a plurality of through-hole screw insertion holes 2d into which fixation screws 4 are screwed. That is, the distal region 2a and the proximal region 2b each have a large number of circular screw insertion holes 2d formed therein, the axial direction of which extends in the thickness direction of the radius fixation plate 2 or in a direction inclined relative to the thickness direction. As necessary, fixation screws 4 are inserted into the screw insertion holes 2d and screwed into both a portion of the screw insertion holes 2d of the radius fixation plate 2 and the radius 3, thereby fixing the radius fixation plate 2 to the radius 3.

As shown in FIG. 2, each screw insertion hole 2d is composed of a large-diameter head receiving portion 2e and a small-diameter female screw portion 2f that is smaller than the inner diameter of the head receiving portion 2e.

As shown in FIG. 2, the fixing screw 4 to be inserted into the screw insertion hole 2d is made of hard metal and is composed of a head 4c and a shaft 4a connected to the head 4c.

The shank 4a has a diameter smaller than the inner diameter of the female threaded portion 2f of the screw insertion hole 2d and is capable of passing through the female threaded portion 2f. The shank 4a is formed with a lead screw 4b that has a self-tapping action on the radius 3 after passing through the screw insertion hole 2d.

A hexalobular recess 4j is formed on the top surface of the head 4c, and the threaded coupling portion of the rotating shaft of the tool 1 is coupled thereto, allowing the fastening screw 4 to rotate forward and backward. The hexalobular recess 4j is just one example, but it is preferable because the hexalobular recess 4j and the hexalobular wrench-shaped threaded coupling portion come into contact at the crests and roots, respectively, and do not slip unless both are fully smoothed. In other words, the hexalobular recess 4j has the effects of efficiently transmitting tightening torque and reducing the risk of damage to the tool or the screw head by eliminating stress concentration.

The head 4c has, for example, an outer diameter that is the same as the inner diameter of the female thread portion 2f, and is temporarily stored in the head storage portion 2e when the screw is fastened. A sub-thread 4d that screws into the female thread portion 2f of the screw insertion hole 2d is formed on the outer peripheral surface of the shank side of the head 4c. Note that instead of a configuration in which the sub-thread 4d is screwed into the female thread portion 2f, the female thread portion 2f may be formed as a thread-forming portion without a female thread being formed in advance, and the sub-thread 4d may be screwed into this thread-forming portion by a self-tapping action.

The inventor considered whether it would be possible to confirm the position of the radius fixation plate 2 by using small piece markers, placing a minimum of two markers, instead of placing wire-shaped markers around the entire outer circumference of the radius fixation plate 2.

As a result, it was found that it would be sufficient to place one marker as the first marker 91 at the end of the distal region 2a and another marker as the second marker 92 in the proximal region 2b.

More specifically, the position of the first marker 91 in the distal region 2a is at the end D1 in the distal direction (the longitudinal direction of the radius fixation plate 2, i.e., the vertical direction in FIG. 1B, the leftward direction in FIG. 4) and at the end D2 in the ulnar direction (the leftward direction of the right hand or the rightward direction of the left hand, the rightward direction in FIG. 1B, the upward direction in FIG. 4) of the distal region 2a.

During postoperative follow-up, as shown in Figures 3A and 3B, it is necessary to confirm that the radius fixation plate 2 does not protrude into the distal radioulnar joint 81. That is, if the radius fixation plate 2 protrudes into the distal radioulnar joint 81 (see the protruding distal region 2Xa of the radius fixation plate 2X in Figure 3A), in other words, if it protrudes from the radius 3 and interferes with the ulna 80, the radius 3 will not be able to rotate around the ulna 80, and the pronation of the wrist shown in Figures 3A and 3C will become impossible.

To avoid this situation, the distal region 2a of the radial fixation plate 2 is configured so as not to protrude into the distal radioulnar joint 81, as shown in FIG. 3A.

A specific method for arranging balls, which are an example of first markers 91 and second markers 92, is to drill holes in the ends of the multiple sheets that make up the radius fixation plate 2 and insert the balls into the holes, thereby accurately positioning the balls at predetermined positions on the radius fixation plate 2. To accurately position the balls at the ends of the radius fixation plate 2 requires a processing margin of, for example, about 1 mm from the edges of the end of the sheets, making it impossible to position the balls at the edges. For this reason, the markers are configured to be positioned at the ends, not the edges.

On the other hand, when the radius fixation plate 2 is produced by injection molding, the spheres can be arranged as follows, for example.

First, an injection mold having a shape that is half the thickness of the radius fixation plate 2 is prepared.

Next, the marker ball is fixed to the surface of the mold, for example, by fitting the marker ball into a recess in the mold.

Next, resin is injected into the mold to form half of the radius fixation plate 2. At this point, the sphere of the marker is partially exposed from the molded product.

Next, the molded product is fitted into a plate-shaped injection mold.

Next, resin is injected into the remaining space in the injection mold, thereby producing the radius fixation plate 2 with the marker balls embedded therein by injection molding.

In an example where the margin is about 1 mm, after inserting the radius fixation plate 2 into the patient's arm through surgery, if the doctor can confirm the position of the ball at the end of the distal region 2a of the radius fixation plate 2 using an X-ray as the first marker 91 after the surgery, it can be estimated that the edge of the radius fixation plate 2 is 1 mm outward from that position. In other words, the position of the radius fixation plate 2 can be accurately estimated based on the shape, length, and width of the radius fixation plate 2, the position of the ball on the radius fixation plate 2, and the margin.

The position of the second marker 92 in the proximal region 2b can be any position on the radial fixation plate 2 away from the first marker 91, as shown in FIG. 1B.

As another example, the second marker 92 can be placed at any position in the proximal region 2b. When the second marker 92 is placed at any position in the proximal region 2b in this manner, the second marker 92 in the proximal region 2b functions solely to identify the position of the radius fixation plate 2. In other words, by accurately marking two points, the first marker 91 and the second marker 92, the second marker 92 can only fulfill the function of enabling the position of the entire radius fixation plate 2 to be identified.

Furthermore, the second marker 92 may be placed in the proximal region 2b on the central axis C in the width direction W of the radius fixation plate 2. As an example, when the second marker 92 is placed on the central axis C in the width direction W of the radius fixation plate 2 and at the end of the proximal region 2b on the distal region side, the second marker 92 may be positioned away from the curved portion 2v on the back surface of the distal region 2a so as not to interfere with the bending of the curved portion 2v.

The reason why the second marker 92 is placed on the central axis C in the width direction W is to make it easier to confirm the central axis C in the width direction W of the radius fixation plate 2. The position of the second marker 92 in the thickness direction of the radius fixation plate 2 (the vertical direction in FIG. 5 ) is arbitrary.

After the radius fixation plate 2 has been inserted into the patient's arm through surgery, if the doctor can confirm the position of the ball in the proximal region 2b of the radius fixation plate 2 using an X-ray as the second marker 92 after surgery, that position is the position through which the central axis C of the width direction W of the radius fixation plate 2 passes, and the orientation of the radius fixation plate 2 can be accurately estimated based on the shape, length, width and position of the ball of the radius fixation plate 2.

The diameter of the sphere of each marker 91, 92 can be, for example, at least 0.5 mm. The minimum diameter of 0.5 mm is set based on the imageability of the markers, i.e., whether they are actually visible or not. For example, a maximum diameter of 1.5 mm is preferable for practical use.

The material of each marker 91, 92 can be any material that can be confirmed by X-ray, such as tantalum, SUS, or Ti.

The markers 91 and 92 can have various shapes, but in terms of workability and operability, a sphere is the most suitable shape, including functionality, followed by a cylindrical (or polygonal prism) shape.

The positions of the first markers 91 in the left-hand radius fixation plate 2 (see FIG. 1B) and the right-hand radius fixation plate 2 are reversed in the left-right direction in FIG. 1B.

Basically, during surgery to implant the radius fixation plate 2 in the arm, the wires arranged in the guide block serve to mark the radius 3. After surgery, the markers 91, 92 on the radius fixation plate 2 are used to mark the radius 3. That is, it is sufficient to use the markers 91, 92 to confirm that the radius fixation plate 2 implanted in the arm has not shifted from the position at the time of surgery.

If there are two markers 91, 92, during an X-ray examination, the positions of the two markers 91, 92 on the ball can be confirmed on X-ray images taken from two or more directions, and the line connecting the two markers 91, 92 can be compared with the line connecting the markers 91, 92 on the actual radius fixation plate 2. From the difference in magnification and the inclination of the two lines, the torsion and flexion of the radius fixation plate 2 implanted in the arm can be determined.

As a specific example of how to confirm the position and orientation of the radius fixation plate 2, the positions of the first marker 91 and the second marker 92 are confirmed on X-ray images from two or more directions, and the confirmed positions of the first marker 91 and the second marker 92 are compared with the positions of the first marker 91 and the second marker 92 of a known embedded radius fixation plate 2, thereby determining the position and orientation of the radius fixation plate 2.

Specifically, the following procedure can be exemplified.

For example, the magnification is calculated by comparing the distance between two markers obtained by X-ray examination with the actual distance between two markers on the implanted radius fixation plate 2. In this case, since a general standard is set for the magnification in the case of X-rays, it is possible to prepare and use comparison data in accordance with this general standard in advance.

Next, the sample shape of the embedded radius fixation plate 2 is enlarged or reduced according to the calculated magnification ratio, and the enlarged or reduced sample shape is matched with the image of the radius fixation plate obtained by X-ray examination to obtain the position and orientation of the embedded radius fixation plate 2.

According to the above embodiment, a first metal marker 91 is placed at the end of the distal region 2a of the radius fixation plate 2 in the distal direction D1 and the end of the ulnar direction D2, and a second metal marker 92 is placed on the central axis C of the width direction W of the proximal region 2b. With this configuration, since the location of the radius fixation plate 2 implanted in the arm is known, the position and orientation of the radius fixation plate 2 can be accurately estimated after surgery based on the positions of the two metal markers 91, 92. That is, the position of the end of the distal region 2a in the distal direction D1 and the end of the ulnar direction D2 can be estimated based on the position of the first marker 91. Furthermore, the position of the second marker 92 can be considered as a passing point of the central axis C of the width direction W of the proximal region 2b. As a result, the position and orientation of the radius fixation plate 2 can be estimated by considering the positions of the first marker 91 and the second marker 92.

The present invention is not limited to the above-described embodiment, but can be embodied in various other forms.

For example, the position of the second marker 92 is not limited to a position away from the curved portion 2v of the distal region 2a, but may be disposed on the curved portion 2v as shown in FIG.

Alternatively, as shown in Figure 7, the second marker 92 may be positioned at the end of the proximal region 2b that is farthest from the distal region 2a, so that the position of the edge of the proximal region 2b of the radius fixation plate 2 can be accurately determined.

It should be noted that any of the various embodiments or modifications described above can be appropriately combined to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.
Although the present invention has been fully described in connection with the embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and it is to be understood that such changes and modifications are included within the scope of the present invention as defined by the appended claims unless they depart therefrom.

The radius fixation plate according to the above aspect of the present invention is made of resin, and after the plate is fixed to the radius with fixation screws, the position and orientation of the plate can be confirmed using two markers that can be detected by X-rays or the like.

1 Radial fixation plate fixation screw tool 2 Radial fixation plate 2a Distal region 2b Proximal region 2d Screw insertion hole 2e Head storage portion 2f Female thread portion 2X Radial fixation plate 2Xa Distal region 3 Radius 3a Fracture portion 3b Radius body 3c Fracture fragment 4 Fixation screw 4a Shank 4b Main screw 4c Head 4d Sub-screw 4j Hexalobular hole 5 Guide block 5d Screw guide hole 80 Ulna 81 Distal radioulnar joint 91 First marker 92 Second marker C Central axis D1 in the width direction of the radial fixation plate Distal direction D2 Ulnar direction W Width direction of the proximal region

Claims (6)

A radial fixation plate implantable in an arm for fixation to a radius, the radial fixation plate having a distal region and a proximal region,
the distal region is a region of the radial fixation plate that includes a curved portion formed by curving a surface of the radial fixation plate facing the radius in a distal direction and is located distal to the curved portion, and the proximal region is a region of the radial fixation plate that is located proximal to the distal region,
a first metallic marker disposed at the distal end and the ulnar end of the distal region;
a second marker made of metal and arranged apart from the first marker ;
The distal region and the proximal region are made of resin .
Radial fixation plate. the second marker is located in the proximal region.
The radial fixation plate of claim 1 . the radial fixation plate is a T-shaped plate member, the proximal region extends in a longitudinal direction of the T, and the second marker is disposed in the proximal region , at a proximal end of the proximal region, and on a longitudinal axis of the T that passes through an end of the T in the longitudinal direction .
The radial fixation plate according to claim 1 or 2. the second marker is located in the proximal region near the distal region;
The radial fixation plate of claim 3 . The second marker is disposed at a position in the proximal region farthest from the distal region.
The radial fixation plate of claim 3 . Each of the markers is a sphere having a diameter of at least 0.5 mm.
The radial fixation plate according to any one of claims 1 to 5 .