Radius fixation plate

Abstract

Provided is a radius fixation plate (2) for accurately confirming the position and orientation thereof on the basis of the positions of metal markers, after radius fracture surgery, the radius fixation plate (2) having a distal region (2a) and a proximal region (2b). The radius fixation plate (2) is configured to comprise: a metal first marker (91) positioned at the end of the distal region in the distal direction (D1) and the end of the distal region in the ulna direction (D2); and a metal second marker (92) that is positioned away from the first marker.

Description

[Technical Field]

[0001] The present invention relates to a resin radius fixation plate that is fixed to the radius with fixation screws. [Background technology]

[0002] When the radius is fractured, a radial 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.

[0003] When the radius fixation plate is fixed to the radius, a plurality of fixation screws are fastened to the radius.

[0004] 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.

[0005] However, metal plates do not allow X-rays to pass through, making it difficult to determine the condition of the fractured area covered by the radius fixation plate.

[0006] Therefore, in recent years, thin resin radius fixation plates have been developed instead of metal plates (see, for example, Patent Document 1).

[0007] [Patent Document 1] Patent Publication No. 2016-016168 Summary of the Invention [Problem to be solved by the invention]

[0008] After the radial fixation plate is surgically fixed to the 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, the X-ray passes through the resin plate, making it impossible to determine the position of the radial fixation plate. Therefore, attempts have been made to place metal marker wires around the outer periphery of the radial fixation plate.

[0009] However, if a large volume of wire-shaped marker (i.e., a marker wire) is placed at the end of the radius fixation plate, the carbon fiber at the end of the radius 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 radius fixation plate where the marker wire is placed, and fracture of the radius fixation plate begins from the portion with low strength. Therefore, it was not possible to place a metal marker wire in the radius fixation plate.

[0010] 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. [Means for solving the problem]

[0011] To achieve the above object, according to one aspect of the present invention, It can be fixed to the radius and implanted in the arm, and 1. A 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, of the distal region The aforementioned a first metallic marker disposed at the distal end and the ulnar end; and a second marker made of metal and spaced apart from the first marker. Along with The distal region and the proximal region are made of resin. , A radial fixation plate is provided. [Effects of the Invention]

[0012] 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. [Brief explanation of the drawings]

[0013] 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: [Figure 1A] 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. [Figure 1B] Plan view of the state of Figure 1A [Figure 2] 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. [Figure 3A] An explanatory diagram showing the positional relationship between the radial fixation plate and the distal radioulnar joint. [Figure 3B] Diagram of the distal radioulnar joint [Figure 3C] Illustration of the effect of wrist pronation and supination on distal radioulnar joint movement [Figure 4] FIG. 10 is an enlarged perspective view showing the location of the first marker on the distal region of the radial fixation plate. [Figure 5] FIG. 1 is a perspective side view showing the positions of the first and second markers of the radial fixation plate. [Figure 6] 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. [Figure 7] 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 INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] 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.

[0016] 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 screw tightening operation of rotating 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 FIG. 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 1A and 1B, the radius fixation plate 2 is configured as a T-shaped plate member with 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.

[0021] The distal region 2a is fixed to the fractured bone fragments 3c with a plurality of fixation screws 4, and the proximal region 2b is fixed to the radial body 3b with a plurality of fixation screws 4 so that the radius fixation plate 2 straddles the fractured bone fragments 3a and the fractured bone fragments 3c are normally connected to the radial body 3b. As an example, when the radius fixation plate 2 is T-shaped as shown in FIG. 1B, the relatively wide region can be the distal region 2a and the relatively narrow region can be the proximal region 2b, but this is not limiting.

[0022] The radius fixing plate 2 is integrally formed by fixing a plurality of sheets (not shown) having a thickness N in a layered manner in the thickness direction.

[0023] The material of the radius fixation plate 2 is, for example, a synthetic resin mixed with long carbon fibers, for example, a thermoplastic resin mixed with long carbon fibers, or a composite material thereof. Examples of thermoplastic resins include PEEK (polyether ether ketone) and polyetherimide. A specific example of the material of the radius fixation plate 2 is carbon fiber reinforced polyether ether ketone (CFRPEEK). Other possible examples of combinations of fibers and resins include, for example, Examples of the material include glass fiber, metal fiber, polyamide fiber, and carbon fiber, and examples of the resin include epoxy resin, PEEK resin, and polyetherimide resin.

[0024] 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.

[0025] As shown in FIG. 2, each screw insertion hole 2d is composed of a large-diameter head housing portion 2e and a small-diameter female screw portion 2f that is smaller than the inner diameter of the head housing portion 2e.

[0026] 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.

[0027] The shank 4a has a diameter smaller than the inner diameter of the female thread portion 2f of the screw insertion hole 2d and is capable of passing through the female thread portion 2f. A lead screw 4b is formed on the shank 4a, which has a self-tapping action on the radius 3 after passing through the screw insertion hole 2d.

[0028] 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 threaded. In other words, the hexalobular recess 4j allows for efficient transmission of tightening torque, and the absence of stress concentration reduces the risk of damage to the tool or the screw head.

[0029] As an example, the head 4c has 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.

[0030] 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.

[0031] As a result, it was found that it would be sufficient to place one marker as a first marker 91 at the end of the distal region 2a and another marker as a second marker 92 in the proximal region 2b.

[0032] More specifically, the position of the first marker 91 in the distal region 2a is at the end of the distal direction (the longitudinal direction of the radius fixation plate 2, i.e., the vertical direction in Figure 1B, the leftward direction in Figure 4) D1, and at the end of the ulnar direction (the leftward direction of the right hand or the rightward direction of the left hand, the rightward direction in Figure 1B, the upward direction in Figure 4) D2 of the distal region 2a.

[0033] 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 cannot rotate around the ulna 80, and the pronation of the wrist shown in Figures 3A and 3C becomes impossible.

[0034] To avoid this situation, the distal region 2a of the radius fixation plate 2 is configured so as not to protrude into the distal radioulnar joint 81, as shown in FIG. 3A.

[0035] 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 radius fixation plate 2 and insert the balls into the holes, thereby accurately positioning the balls at predetermined positions on radius fixation plate 2. To accurately position the balls at the ends of 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.

[0036] On the other hand, when the radius fixation plate 2 is produced by injection molding, the spheres can be arranged as follows, for example.

[0037] First, an injection mold having a shape that is half the thickness of the radius fixation plate 2 is prepared.

[0038] 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.

[0039] 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.

[0040] Next, the molded product is fitted into a plate-shaped injection mold.

[0041] Next, resin is injected into the remaining space in the injection mold, thereby producing the radius fixation plate 2 with the marker spheres embedded therein by injection molding.

[0042] In an example where the margin is about 1 mm, after the radius fixation plate 2 has been surgically inserted into the patient's arm, if the doctor can confirm the position of the ball at the end of the distal region 2a of the radius fixation plate 2 as first marker 91 by X-ray 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.

[0043] 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.

[0044] 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 way, 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 its function of enabling the position of the entire radius fixation plate 2 to be identified.

[0045] Furthermore, the second marker 92 may also 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 so as not to interfere with the curving of the curved portion 2v on the back surface of the distal region 2a.

[0046] Here, 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.

[0047] After the radius fixation plate 2 is surgically inserted into the patient's arm, 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 the 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.

[0048] 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.

[0049] The markers 91 and 92 can be made of any material that can be confirmed by X-ray, such as tantalum, SUS, or Ti.

[0050] The markers 91 and 92 can have various shapes, but when considering ease of processing and operability, including functionality, a sphere is the most suitable, followed by a cylindrical (or polygonal prism) shape.

[0051] Note that the positions of first markers 91 on radius fixation plate 2 for a left hand (see FIG. 1B) and radius fixation plate 2 for a right hand are reversed in the left-right direction in FIG. 1B.

[0052] Basically, during surgery to implant the radius fixation plate 2 in the arm, the wire arranged in the guide block serves to mark the radius 3. After surgery, the markers 91 and 92 on the radius fixation plate 2 are used to mark the radius 3. In other words, it is sufficient to use the markers 91 and 92 to confirm that the radius fixation plate 2 implanted in the arm has not shifted from the position at the time of surgery.

[0053] If there are two markers 91, 92, during an X-ray examination, the positions of the two markers 91, 92 on the sphere 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.

[0054] 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 implanted radius fixation plate 2, thereby determining the position and orientation of the radius fixation plate 2.

[0055] Specifically, the following procedure can be exemplified.

[0056] 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 also possible to prepare and use comparison data in accordance with this general standard in advance.

[0057] 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.

[0058] According to the embodiment described above, 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 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.

[0059] The present invention is not limited to the above-described embodiment, but can be embodied in various other forms.

[0060] 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.

[0061] 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.

[0062] 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. [Industrial Applicability]

[0063] 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, etc. [Explanation of symbols]

[0064] 1 Radial Plate Fixation Screw Tool 2 Radius Fixation Plates 2a Distal region 2b Proximal region 2d screw insertion hole 2e Head compartment 2f Female thread 2X Radial Fixation Plates 2Xa distal region 3 Radius 3a Fracture area 3b Radial body 3c fracture fragment 4 fixing screws 4a Shaft 4b Lead screw 4c head 4d Sub-screw 4j hexalobular socket 5 Guide Block 5d screw guide hole 80 Ulna 81 Distal radioulnar joint 91 First Marker 92 Second Marker C. The central axis of the radial fixation plate in the width direction D1 distal direction D2 Ulnar direction W width direction of the proximal region

Claims

1. A radial fixation plate that can be fixed to a radius and implanted in an arm, and that has 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.

2. the second marker is located in the proximal region. The radial fixation plate of claim 1 .

3. The radial fixation plate is a T-shaped plate member, the proximal region extends in the longitudinal direction of the T, and the second marker is positioned in the proximal region, at the proximal end of the proximal region, and on the longitudinal axis of the T passing through the end of the T in the longitudinal direction. The radial fixation plate according to claim 1 or 2.

4. the second marker is located in the proximal region near the distal region; The radial fixation plate of claim 3 .

5. The second marker is disposed at a position in the proximal region farthest from the distal region. The radial fixation plate of claim 3 .

6. 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.

Images