JPS5883954A - Plate for bonding bone fractures - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The AO method (THE, ASSOC
IATION FOR THE STUD
Y OF OSTEOSYNTHES. IS)
The present invention relates to a bone fracture bonding plate used in such cases.

Conventional fracture bonding plates are shown in Figures 15 and 1.
As shown in Figure 8, play with uniform thickness) P, P'
is known.

Therefore, first of all, let me explain about one of the plays (P). Plate P is a thick metal plate with a thickness of about 5 mm that was made for the purpose of getting out of bed early, and the rigidity of plate P is high and uniform at both the center and the edges. It is something.

Therefore, when using the plate P, as shown in Fig. 16, the plate P is fixed with the screws S with the fracture line f joined, and the plate P is played as is until the fracture F heals.) Since the patient leaves the bed and lives a normal life with P fixed, strong external forces often act on the bones including the fracture F due to falls and the like.

In other words, the question is how the external force acting on this bone acts on the fracture F through the plate P.
In the case of a thick plate P, since the rigidity is as high at the edges as in the center as described above, as shown in the shear force diagram L in FIG.
The shearing force acting on the bone becomes extremely large,
The plate end fracture had occurred as shown by the imaginary line F' in Figure 16.

In addition, when an external force is applied to the plate Pt in a fixed state, the plate P itself has high rigidity, and since the plate P is firmly fixed on both sides of the fracture line f by the screws S, As shown in the shear force diagram in FIG. 16, almost no shear force from the plate P acts in the vicinity of the fracture line f. In other words, with respect to the external force applied to the fracture F, a force bypass phenomenon occurs in which the external force avoids the vicinity of the fracture line f and only the plate P is involved in transmitting the force, and no force is transmitted to the vicinity of the fracture line f. Therefore, near the fracture line f, the calcium content of the bone is lost (bone demineralizes when no physiological force is applied to it), resulting in osteoporosis.
), the strength of the bone itself decreased, and as shown in FIG. 17, a re-fracture occurred in which the fracture F, which had healed after the plate P was removed, fractured again.

As mentioned above, conventional thick plates P have the disadvantage of causing plate edge fractures and re-fractures, and the fracture incidence rate for both types of fractures is 20% among patients treated with fracture union using conventional plates P. There are reports that rFRA can reach up to %.
It was published in CTURES vol. IJ (published in 1957), and the same magazine also includes information on the mechanism of plate edge fractures and re-fractures, and that it is not recommended to use conventional plate P for the treatment of all fractures. This proves how serious the drawbacks of the conventional plate P are.

jj Next, to explain the plate P' shown in Fig. 18, the plate P' has a plate structure with low overall rigidity by reducing the thickness, and the shear force diagram in Fig. 19 shows the plate P'. As the shearing force acting on the bone from the plate end is small, plate end fracture hardly occurs, and a slightly reduced external force acts near the fracture line f without causing a force bypass phenomenon. Therefore, re-fractures hardly occur, but the drawback is that early mobilization, which is the main objective of the AO method, cannot be achieved.

The present invention was made by researching the above-mentioned drawbacks of conventional fracture joining plates, and developed a fracture joining plate with a new structure that eliminates these drawbacks.The purpose of the present invention is to: By varying the rigidity of the plate based on the function of each part of the plate body, it provides strong fixation that enables early mobilization, while reducing the risk of plate end fractures and osteoporosis significantly compared to conventional methods. The object of the present invention is to provide a plate for fracture bonding that reduces the number of fractures.

Next, the embodiments of the present invention shown in the drawings will be described in detail below.

First, the drawings shown in FIGS. 1 and 2 are a perspective view and a central vertical cross-sectional view showing an embodiment of the plate of the present invention, which is characterized by a plate structure in which different rigidities are achieved by different thicknesses. To explain the specific configuration, 1.
is the plate body made of stainless steel and has a curved bottom surface to fit the fracture site, 2 is the large fixing screw drilled in the plate body 1, la is the center part of the plate body 1, lb, lb are the plates This is the end of the main body 1.

As shown in FIG.
In the embodiment shown in FIGS. 1 and 2, the thickness is reduced by making the upper surface of the plate main body 1 curved and concave from the center portion 1a to the end portions 1b and lb. The structure is designed to reduce the size.

Note that the drawings shown in FIGS. 3 and 4 are partially omitted central vertical cross-sectional views of the embodiment, and FIG. 4 shows a structure in which the thickness is reduced by making the upper surface of the plate main body 1 a curved inclined convex surface from the center portion 1a to the end portions 1b.

As described above, in the embodiments shown in FIGS. 1 to 4, the central part 1b of the plate body 1 has a high rigidity by simply changing the thickness without changing the width of the plate body 1. It has a wide cross-sectional area shape, and the end portions 1b and lb have a narrow cross-section ram shape with low rigidity.

In addition, regarding the specific thickness, the size of the plate body 1 differs depending on the part to which it is applied, the fracture condition, etc., and the influence of external force varies depending on the place where the plate is attached, so it should be determined according to these conditions. In addition, it is set appropriately depending on the material of the plate body 1.

Next, the drawing shown in FIG. 5 is a perspective view showing the other side of the plate of the present invention, and the difference from the embodiment is that the width of the plate body 1 is changed from the center part 1a to the end part 1b. This point is that the wide pieces 1c, lc, 1c, and Ic are formed by widening the width.

In other words, the thickness of the plate body 1 is changed from the center part 1a to the end part 1.
The rigidity of the end portions 1b, 1b is reduced by reducing the width toward the ends 1b, 1b, and the wide piece 1c.

This is a preferable example because the stress is dispersed by forming 1c+ lc and lc, and the shearing force at the plate end is even lower than in the example.

Next, the drawings shown in FIGS. 6 and 7 are perspective views showing the other side of the plate of the present invention, in which the plate body 1 is composed of a thin plate base 1d and a spindle-shaped protrusion 1e. The configuration shown in FIG. 6 has a single spindle-shaped protrusion 1e, and the configuration shown in FIG. 7 has a single spindle-shaped protrusion 1e',
1 e″, le are arranged in multiple sizes.

In other words, the central part 1ati of the plate body 1 becomes the wide part of the spindle-shaped projection 1e, so it has a wide cross-sectional area and high rigidity, and conversely, the end parts 1b and lb become the narrow parts of the spindle-shaped projection 1e. Therefore, it has a narrow cross-sectional area and low rigidity.

Next, the drawing shown in FIG. 8 is a perspective view showing another embodiment of the plate of the present invention, in which the plate main body 1 is entirely spindle-shaped, and the rigidity is varied depending on the width and narrowness of the cross-sectional area as described above. It is structured as follows.

Next, the drawing shown in FIG. 9 shows the other side of the plate of the present invention, which is called a special plate, and is used when a finger is broken.

This special plate also has high and low rigidity depending on the thickness of the plate body 1, as in the embodiment.

Next, the drawing shown in FIG. 10 shows the other side of the plate of the present invention, which is called a rectangular plate, and the structure is largely different from the other embodiments in that it has a driving part 1f.
As in the other embodiments, the screw fixing part has problems such as plate end fracture, so the thickness of the plate body l is made to have a low rigidity as in the embodiment.

The configuration of the plate of the present invention has been explained above using examples, but the plate material is not limited to stainless steel, for example, and may be made of other metal materials such as titanium alloy, reinforced plastic, etc. It may be a special plastic that gradually becomes brittle over time, or it may be a composite material made of a combination of these materials.

Further, the cross-sectional shape is not limited to the embodiment, and in short, the central portion 1a of the plate body 1, where bending stress acts greatly, has a high rigidity and wide cross-sectional shape so that early exit from the bed is possible, and the plate body 1 Of these, the end portion 1b on which a large shearing force acts may have a narrow surface shape with low rigidity so as to prevent plate end fracture.

Therefore, when using the plate of the present invention, the first
As shown in Figure 1, the plate of the present invention is firmly fixed to the fracture F centered on the fracture line f with screws S,
Until the fracture F has healed, the patient can leave the bed and carry out all normal activities with the plate fixed. In other words, when using the plate of the present invention, the plate body 1 Since the central part 1a, where a large bending stress acts, is made to have high rigidity, even if an external force is applied to the fracture part F, it will not affect the joint part, which is the fracture line f, sufficiently. It can be supported by the plate body 1,
It is possible to get out of bed early.

In addition, since the end portion 1b of the plate body 1 on which a large shearing force acts has low rigidity, as shown by the shearing force 1L in the line in Figure 12, patients who have undergone bonding treatment using the plate of the present invention may suffer from falls, etc. Even if a large external force is applied to the fracture F, the shearing force acting from the plate end to the bone is small, and the end lb of the plate body 1 is bent, resulting in a plate end fracture compared to the case of a conventional plate. This is a significant decrease.

In addition, since the plate body 1 is not made to have high rigidity as a whole, the stress distribution is smoothed out as a whole, as shown in the shear force diagram in Figure 12, and is not extremely rigid as in the conventional case. This means that no force bypass phenomenon occurs.

This creates some force near the fracture line f]
Osteoporosis, which is caused by the loss of calcium content in the bone due to use of the plate, is almost eliminated, and the number of re-fractures after plate removal due to a decrease in the strength of the bone itself is significantly reduced compared to the past.

Incidentally, FIG. 13 is an explanatory diagram of the usage state of the special plate shown in FIG. 9, and FIG. 14 is an explanatory diagram of the usage state of the M-square plate shown in FIG. 10.

Since the bone fracture joining plate of the present invention can be configured and used as described above, it enables early mobilization and at the same time significantly reduces plate end fractures and osteoporosis compared to the past. Furthermore, it has the outstanding effect of significantly reducing re-fractures after plate removal. In addition, the fracture healing method using a plate has not changed in any way from before, and the structure of the plate itself is simple, so it has the effect of providing an extremely effective plate in the field of fracture healing treatment. Be equipped.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the bone fracture joining plate of the present invention, FIG. 2 is a central vertical cross-sectional view 2 of the same example, and FIGS. 3 and 4 show thickness changes and other changes in the same example. FIG. 5 is a perspective view showing the other side of the plate of the present invention; FIGS. 6 to 8 are perspective views showing the other side of the plate; FIG. 9 is a perspective view showing the other side of the plate. A perspective view showing a special plate, which is the other side of the plate, FIG. 11 is an explanatory diagram of the plate according to the present invention in use, FIG. 12 is an explanatory diagram of the stress effect when the plate is in use, and FIG. FIG. 14 is an explanatory diagram of the usage state of the special plate. FIG. 14 is an explanatory diagram of the M-square plate of the present invention. FIG. 15 is a perspective view showing a conventional plate. FIG. 16 is an explanatory diagram of the usage state of the same plate. The figure is an explanatory diagram showing the state after the plate is removed.
Fig. 18 is a perspective view showing the other side of the conventional grating;
The figure shows the state in which the plate is used. 1@・Plate body, 2@・Fixing screw hole, 1a・Center portion, 1b・・End portion 0 Patent Applicant Co., Ltd. Tomonobu Development Patent Office Commissioner Haruki Shimada 1. Display of the case 1982 Patent Application No. 182593 2, Name of the invention: Plate for fracture attachment 3, Person making the amendment Relationship to the case: Patent applicant Yuun Kai Pano Name: Tomonobu Kaihatsu Co., Ltd. 4, Agent. 329 to be corrected as "a perspective view showing , and FIG. 10 is a perspective view showing an angular plate on the same side."

Claims (1)

[Claims] 1) In a fracture bonding plate in which the plate body 1 is provided with screw holes 2 for fixing to the fractured part, the plate body 1
The central portion 1a, where a large bending stress is applied, has a high rigidity and a wide cross-sectional area shape to enable early exit from bed, and the end portion 1b, where a large shearing force acts, of the plate body 1 has a low rigidity to prevent plate edge fracture. A fracture bonding plate characterized by having a narrow cross-sectional area shape.