JP2010220762A - Bone plate and bone plate system - Google Patents

Abstract

A screw is fastened to a tibia or the like at a desired angle without deforming a bone plate and without generating metal powder.
SOLUTION: A plurality of screw holes 5a penetrating in the plate thickness direction, which are formed in a strip shape arranged along the bone surface and are arranged at intervals in the longitudinal direction, are arranged at the end in the longitudinal direction. The at least one screw hole 5a includes two female screw portions 6 opposed in the longitudinal direction and two relief portions 7 having an inner diameter dimension equal to or larger than the valley diameter of the female screw portion 6 alternately in the circumferential direction. A bone plate 1 is provided.
[Selection] Figure 4

Description

  The present invention relates to bone plates and bone plate systems.

Conventionally, as a bone plate for fixing a part of a long bone including a fractured femur and tibia, a band plate shape having a screw hole for fastening to a male screw provided on the heads of a plurality of screws fastened to the long bone (See, for example, Patent Document 1).
A bone plate having three or more thread rows interrupted in the circumferential direction by at least three recesses in the screw hole is also known (see, for example, Patent Document 2).

Special table 2007-500069 gazette Special table 2007-506450 gazette

  However, the direction of the screw fastened with respect to the bone plate is fixed to the bone plate of Patent Document 1. For this reason, for example, the surface shape of the tibia after osteotomy is different each time, as in the case of high-knee osteotomy for osteoarthritis of the knee. If the bone plate is not deformed according to the surface shape, there is a disadvantage that the screw cannot be fastened to the tibia or the like at a desired angle.

  Moreover, in the bone plate of patent document 2, when the male screw provided in the head of the screw is fastened to three or more screw threads interrupted by the recess in the female screw, the male screw thread is used as the female screw. The screw shaft can be tilted by one pitch by engaging the different screw threads, but in this case the thread of the male thread must cross one of the threads of the female thread. However, there is an inconvenience that metal powder is generated and scattered in the affected area when fastening.

  The present invention has been made in view of the above-described circumstances, and the screw is fastened to the tibia or the like at a desired angle without deforming the bone plate and without generating metal powder. It is an object of the present invention to provide a bone plate and a bone plate system that can be used.

In order to achieve the above object, the present invention provides the following means.
The present invention is formed in a strip shape arranged along the bone surface, and has a plurality of screw holes penetrating in the plate thickness direction arranged at intervals in the longitudinal direction, and is arranged at the end portion in the longitudinal direction. Provided is a bone plate in which at least one screw hole alternately includes two female screw portions opposed to each other in the longitudinal direction and two relief portions having an inner diameter dimension equal to or larger than a valley diameter of the female screw portion in the circumferential direction. To do.

According to the bone plate according to the present invention, the screw is fastened to the bone through the screw hole in a state along the bone surface, and the male screw portion provided on the screw at the final stage of the fastening is provided on the bone plate. By fastening to the female screw portion of the screw hole, the screw can be fixed to the bone plate, and thereby the bone plate can be fixed to the bone.
In this case, the male screw portion of the screw is fastened so as to be spanned between two female screw portions facing each other in the longitudinal direction of the bone plate. Since the female screw part of the screw hole is not continuous in the circumferential direction and is separated by the relief part, the screw is fastened to the screw hole except for a fastening state in which the screw axis is aligned with the screw hole axis. A fastened state can also be realized.

  That is, by shifting the thread of the female threaded portion of the screw hole to which the male threaded portion of the screw is fastened by one thread or more in either direction in the two female threaded portions, the screw axis is changed to the axis of the screw hole. On the other hand, a fastening state in which the bone plate is inclined in any direction in the longitudinal direction can be achieved. And since the escape part which does not mesh with the male screw part of the screw is provided between the two female screw parts, even if the axis of the screw is inclined with respect to the axis of the screw hole, the male screw part of the screw is not Without traversing the female screw portion, it is possible to prevent inconvenience that the female screw portion is shaved during fastening and chips are generated.

As a result, the fixing angle of the screw to the bone plate can be selected from three or more angles in a plane along the longitudinal direction of the bone plate. Can be fixed.
As a result, even if the surface shape of the tibia after osteotomy is different each time, as in the case of high-knee osteotomy for osteoarthritis of the knee, the surgeon can The bone plate does not need to be deformed in accordance with the surface shape of the screw, and the screw can be fastened to the bone plate by selecting an appropriate fixing angle with respect to the tibia or the like.

In the above invention, the axes of the plurality of screw holes arranged adjacent to each other in the longitudinal direction are arranged in a parallel positional relationship with an interval in the direction of twisting or crossing the longitudinal direction. May be.
By doing in this way, a screw can be fastened so that the axis line of the screw fastened by the screw hole adjacent to a longitudinal direction may not cross. Therefore, even when a long screw is used, it is possible to prevent the inconvenience that the screws interfere with each other.

Moreover, in the said invention, you may have a some screw hole adjacent to the edge part of the said longitudinal direction at intervals in the direction which cross | intersects the said longitudinal direction.
The fixing force between the female screw part of the screw hole and the male screw part of the screw is generated only at the two female screw parts facing the longitudinal direction of the bone plate, and the male screw is in the direction intersecting the longitudinal direction. It does not occur because the part is arranged in the escape part. Therefore, in each screw hole, a high fixing force is generated with respect to the moment generated in the plane along the longitudinal direction of the bone plate, but it is weakened in the direction intersecting it. According to the present invention, by causing a plurality of screw holes to be adjacent to each other at intervals in the direction intersecting the longitudinal direction, the force in the direction intersecting the longitudinal direction of the bone plate is generated by the force generated in the axial direction of each screw. Also, a high fixing force can be obtained.

Moreover, in the said invention, the said relief part of the said screw hole may be provided over the range of 90 degrees-150 degrees in the circumferential direction, respectively.
In this way, it is possible to obtain a sufficient fastening force between the female screw portion of the screw hole and the male screw portion of the screw, and also when the screw axis is inclined with respect to the screw hole axis. Generation of chips can be suppressed by avoiding interference between the threaded portion and the male threaded portion.

Moreover, in the said invention, the said internal thread part may be a taper internal thread, and may be formed in the inner surface of a spherical-shaped screw hole.
By doing in this way, even when the axis of the screw is inclined with respect to the axis of the screw hole, it is possible to achieve a fastened state between the male screw portion and the female screw portion over a wide range and obtain a high fixing force. it can.

The present invention also includes any one of the bone plates described above and a plurality of screws for fixing the bone plate to the bone, and the screw has a female screw in a screw hole provided in the bone plate on the head. A bone plate system having an external thread that is fastened to.
The present invention also includes the bone plate and a plurality of screws for fixing the bone plate to the bone, and the screw is fastened to a taper female screw of a screw hole provided in the bone plate at a head of the bone plate. A bone plate system having a tapered male thread is provided.
Furthermore, the present invention includes the bone plate and a plurality of screws for fixing the bone plate to the bone, and the screws are spherical screws provided on the bone plate on the outer surface of the spherical head. A bone plate system is provided having a male thread that is fastened to a female thread on the inner surface of a hole.

  According to the present invention, there is an effect that the screw can be fastened to the tibia or the like at a desired angle without deforming the bone plate and without generating metal powder.

It is a front view which shows the bone plate which concerns on one Embodiment of this invention. It is a bone plate system longitudinal cross-sectional view based on this embodiment which has the bone plate of FIG. It is a longitudinal cross-sectional view in the wide part of the bone plate which shows the bone plate system of FIG. It is the (a) partial longitudinal cross-sectional view of the internal thread part provided in the wide part of the bone plate of FIG. 1, (b) The partial longitudinal cross-sectional view of the state in which the screw was fastened according to the axis line. FIG. 5 is a partial vertical cross-sectional view of a female screw portion in a state where the screw and the screw hole in FIG. 4 are fastened by being inclined with (a) being inclined in one direction and (b) being in another direction. It is a front view which shows the modification of the bone plate of FIG. FIG. 6 is a partial longitudinal sectional view showing a modification of the bone plate of FIG. 1 and the bone plate system of FIG. 2.

A bone plate 1 and a bone plate system 2 according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 2, the bone plate system 2 according to the present embodiment includes a bone plate 1 and a plurality of screws 3 for fixing the bone plate 1 to a side surface of a bone, for example, the tibia A. Yes.

  The bone plate 1 according to the present embodiment is an elongated band plate-like member that is fixed to the side surface of the tibia A after osteotomy in high-knee osteotomy for knee osteoarthritis, and ends from the diaphysis of the tibia A. In order to be able to follow the curved surface shape of the side surface of the tibia A at the position of transition toward the part, it has a slightly curved shape in accordance with a typical surface shape.

The bone plate 1 is provided with a wide portion 4 whose width dimension extends in a direction orthogonal to the longitudinal direction at one end in the longitudinal direction, and is formed in a substantially T shape as a whole.
The bone plate 1 is provided with a plurality of, for example, six screw holes 5a and 5b at intervals in the longitudinal direction. The wide portion 4 is provided with a plurality of, for example, three screw holes 5a at intervals in a direction intersecting the longitudinal direction.

  Of the six screw holes 5a and 5b spaced apart in the longitudinal direction, the five screw holes 5b excluding the screw holes 5a provided in the wide portion 4 are normal taper screws (taper female screws). It has an inner diameter dimension that gradually decreases from one side to the other side in the thickness direction, that is, toward the surface facing the tibia A. The screw holes 5 a and 5 b have an axis along the thickness direction of the bone plate 1.

  As shown in FIG. 1, the screw holes 5a and 5b adjacent to each other in the longitudinal direction are slightly parallel to each other in the direction intersecting the longitudinal direction so that their axes are substantially parallel or twisted. ing. Thereby, even if the length of the screw 3 fastened to these screw holes 5a and 5b is made sufficiently long, they do not interfere with each other.

  In the bone plate 1 according to the present embodiment, the three screw holes 5a provided in the wide portion 4 are provided with a female screw portion 6 and the female screw portion 6 as shown in FIGS. The two relief portions 7 having an inner diameter larger than the valley diameter are alternately arranged in the circumferential direction. Each escape portion 7 is provided over a range of 90 ° in the circumferential direction. In addition, it is not limited to this range, You may provide over arbitrary ranges of 90 degrees-150 degrees.

  Thus, the two female screw portions 6 are opposed to each other in the radial direction and are separated from each other by the two escape portions 7. The female screw portion 6 is configured by a taper screw (taper female screw) whose diameter dimension gradually decreases in one direction in the plate thickness direction.

  As shown in FIGS. 2 and 3, the screw 3 is formed in an elongated round bar shape, and a male screw 3a for bone fixation fastened to a lower hole (not shown) formed in the tibia A on the outer peripheral surface thereof. And a male screw (male screw portion) 3b for fixing the plate made of a taper screw (taper male screw) fastened to the screw holes 5a and 5b of the bone plate 1 on the outer peripheral surface of the head of the screw 3. Yes.

The operation of the bone plate 1 and the bone plate system 2 according to the present embodiment configured as described above will be described below.
In order to perform high-level tibial osteotomy for knee osteoarthritis using the bone plate system 2 according to the present embodiment, incision is performed in a direction inclined with respect to the longitudinal axis of the tibia from the inner surface of the tibia A to the outside. And the cutting plane is enlarged using a predetermined tool. Then, in a state in which the wedge-shaped filling material B is inserted between the expanded cut surfaces, as shown in FIG. 2, the bone plate 1 is directed to the inner side surface of the tibia A, and the wide portion 4 is sandwiched between the cuts. One screw hole 5b close to the other and four other screw holes 5b are arranged, and a lower hole is formed in the screw hole 5b.

  At this time, for the screw holes 5b other than the wide portion 4, a lower hole is formed along the axial direction of each screw hole 5b. On the other hand, for the screw hole 5a of the wide portion 4, a lower hole is formed so as to be substantially horizontal to the end face of the tibia A. Then, the screw holes 5a and 5b are passed through and the male screws 3a for fixing the bone of the screw 3 are fastened to the lower holes. Finally, the plate provided on the head of the screw 3 in the screw holes 5a and 5b. The fixing male screw 3b is fastened.

  Thereby, the bone plate 1 is fixed to the tibia A in a state where the bone plate 1 is disposed along the surface of the tibia A. In this case, the female screw of each screw hole 5a, 5b and the male screw 3b for fixing the plate of the screw 3 are constituted by a taper screw. It can be fixed to the surface of A.

  Further, according to the bone plate 1 and the bone plate system 2 according to the present embodiment, the screw hole 5 a provided in the wide portion 4 has an inner diameter larger than the female screw portion 6 and the valley diameter of the female screw portion 6. Since the two relief portions 7 having dimensions are alternately arranged in the circumferential direction, as shown in FIG. 4B, the two relief portions 7 are spanned over the two female screw portions 6 divided by the relief portion 7. The male screw 3b of the screw 3 is disposed.

  At this time, the angle of fastening to the female screw portion 6 of the screw hole 5a of the male screw 3b of the screw 3 is not limited to one. That is, as shown in FIG. 4B, in addition to the angle at which the axis of the screw 3 and the axis of the screw hole 5a coincide with each other, as shown in FIGS. It is possible to select three fastening methods having an angle in which the fastening position to the portion 6 is shifted in one direction by one screw thread with respect to the fastening position to the other female screw portion 6.

  In the high tibial osteotomy for knee osteoarthritis, the degree of opening of the incision formed in the tibial A varies depending on the degree of deformation of the tibial A, and the surface shape of the tibial A varies from patient to patient. According to the bone plate 1 and the bone plate system 2 according to the present embodiment, the bone plate 1 having a single shape is applied to all patients by appropriately selecting a fastening method of the screw 3 to the screw hole 5a. However, there is an advantage that the fixing direction of the screw 3 can be set to an appropriate direction.

  That is, when the bone plate 1 having a single shape is applied to all patients, the screw 3 that fixes the wide portion 4 is penetrated through the end surface of the tibia A when the fixing direction of the screw 3 is single. It may be arranged, or the screw 3 may be arranged in a direction penetrating the filling material B. On the other hand, according to the present embodiment, there is no such inconvenience, and the screw 3 for fixing the wide portion 4 is fixed without forcing the operator to perform troublesome operations such as deforming the bone plate 1 in the surgical field. It can be fastened in a direction substantially parallel to the end face of the tibia A.

  Further, according to the bone plate 1 and the bone plate system 2 according to the present embodiment, the screw 3 is fixed to the screw threads different from each other with respect to the two female screw portions 6 facing the longitudinal direction of the screw hole 5a in the wide portion 4. Even if the male screw 3b is fastened, the male screw 3b of the screw 3 does not cross the thread of the female screw portion 6 because the escape portion 7 is provided. It is possible to prevent the occurrence of inconvenience that metal powder is generated.

  Further, since the female screw portion 6 of the screw hole 5a of the bone plate 1 and the male screw 3b for fixing the plate of the screw 3 are constituted by taper screws, the degree of freedom for fastening the male screw 3b to the female screw portion 6 is high. Even if the screw 3 is inclined with respect to the axis of the screw hole 5a, there is an advantage that both can be more securely fastened.

  Moreover, in this embodiment, since the wide part 4 was provided in the bone plate 1, and the three screw holes 5a were provided in the wide part 4 at intervals in the direction crossing the longitudinal direction of the bone plate 1, By the tension of the three screws 3 fastened to these screw holes 5a, the moment applied to the bone plate 1 can be received, and even when the tibia A is twisted, the bone plate 1 is held firmly fixed. be able to.

  In addition, in this embodiment, although the bone plate 1 was formed in the substantially T shape, it is not limited to this, You may form in a substantially L shape. Moreover, although the three screw holes 5a were provided in the wide part 4, it may replace with this and may arrange | position arbitrary numbers of two or more screw holes 5a. Further, in the example shown in FIG. 1, the bone plate 1 has a bent shape to prevent the opposite end of the wide portion 4 from protruding to the outside of the tibia when fixed to the tibia A. However, it is not limited to this shape.

  In addition, although the three screw holes 5a of the wide portion 4 are arranged at intervals in the direction orthogonal to the longitudinal axis, instead of this, as shown in FIG. You may arrange | position at intervals in the direction which cross | intersects at an angle. By doing in this way, also in the wide part 4, the axis line of the screw hole 5a can be arrange | positioned in a mutually twisted position, and since an axis line does not cross | intersect, it is fastened so that it may not mutually interfere even if it uses the long screw 3. can do.

In the present embodiment, only the screw hole 5a provided in the wide portion 4 has a structure having the female screw portion 6 and the relief portion 7 alternately in the circumferential direction. A similar structure may be adopted for the screw hole 5a.
Moreover, in this embodiment, although the case where the thread of the female thread part 6 which opposes was shifted and fastened by 1 thread | yarn was demonstrated, it replaced with this and the pitch of a screw | thread is restrained sufficiently small, and it is 2 thread parts. You may decide to shift and fasten.

  Further, in the present embodiment, the female screw portion 6 of the screw hole 5a provided in the wide portion 4 and the male screw 3b for fixing the plate of the screw 3 fastened thereto are configured by taper screws. As shown in FIG. 7, an internal thread portion 6 and an external thread 3 b having a thread extending toward the substantially central direction of the sphere may be employed on the inner and outer surfaces curved in a substantially spherical shape. By doing in this way, even if the axis of the screw 3 is inclined with respect to the axis of the screw hole 5a, a large contact range between the female screw portion 6 and the male screw 3b for fixing the plate can be secured. There is an advantage that a sufficient fixing force can be obtained.

A Tibial bone
1 Bone Plate 2 Bone Plate System 3 Screw 3b Male Thread (Male Thread)
5a, 5b Screw hole 6 Female screw part 7 Escape part

Claims (9)

Formed in the shape of a strip placed along the bone surface,
Provided with a plurality of screw holes penetrating in the thickness direction arranged at intervals in the longitudinal direction,
At least one screw hole disposed at an end in the longitudinal direction has two female screw portions opposed in the longitudinal direction and two relief portions having an inner diameter dimension equal to or larger than the valley diameter of the female screw portion in the circumferential direction. A bone plate that is provided alternately.   The axes of the plurality of screw holes arranged adjacent to each other in the longitudinal direction are arranged in a parallel positional relationship with a space in a twisting relationship or in a direction intersecting the longitudinal direction. The bone plate described.   The bone plate according to claim 1, wherein the bone plate has a plurality of screw holes adjacent to each other at intervals in a direction intersecting the longitudinal direction at an end portion in the longitudinal direction.   The bone plate according to any one of claims 1 to 3, wherein the escape portion of the screw hole is provided in a circumferential direction over a range of 90 ° to 150 °.   The bone plate according to claim 1, wherein the female screw portion is a tapered female screw.   The bone plate according to claim 1, wherein the female screw portion is formed on an inner surface of a spherical screw hole. The bone plate according to any one of claims 1 to 6,
A plurality of screws for fixing the bone plate to the bone;
A bone plate system in which the screw has a male screw portion fastened to a female screw portion of a screw hole provided in the bone plate at a head thereof. A bone plate according to claim 5;
A plurality of screws for fixing the bone plate to the bone;
The bone plate system in which the screw has a taper male screw fastened to the taper female screw of a screw hole provided in the bone plate on an outer surface of the head. A bone plate according to claim 6;
A plurality of screws for fixing the bone plate to the bone;
The bone plate system in which the screw has a male screw fastened to the female screw portion of the inner surface of a spherical screw hole provided in the bone plate on the outer surface of the spherical head.

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