JP3752146B2 - External fixator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an external fixator used for fixing a fracture portion, and more particularly to an external fixator suitable for a wrist joint fracture.
[0002]
[Prior art]
The external fixator has a rod-shaped member disposed along the fractured portion, a pair of supports disposed at both ends thereof, and a plurality of pins whose one ends are fixed at right angles to the support. The bone is fixed by inserting the other end of the pin into the bone of the fracture part. Conventionally, when this external fixator is applied to a wrist joint fracture, the fracture site is fixed with a screw, wire, etc., the joint surface is reduced, and the external fixation is performed across the wrist joint. I was wearing a bowl.
[0003]
[Problems to be solved by the invention]
However, the pin insertion period can be as long as several months required for the affected area to heal, so it is long when applying conventional external fixators to wrist joint fractures. There was a problem that it was difficult to move the wrist joint over a period of time and the motor function of the fingers was lowered. In addition, since the conventional external fixator uses a thick and hard pin with a diameter of about 3 mm, there are disadvantages that the insertion location is limited and the clamp cannot be held unless the insertion angle is set strictly with a drill guide.
[0004]
The present invention has been made in view of these circumstances, and it is possible to fix the bone fragment by inserting three or more pins into the bone fragment caused by the fracture of the wrist joint from multiple directions. In addition , an object of the present invention is to provide an external fixator that can be easily held in a clamp by elastically deforming even if the pin is inserted into the bone fragment from multiple directions as described above .
[0005]
[Means for Solving the Problems]
In order to solve the above problems, an external fixator of the present invention is an external fixator having a pair of supports disposed at both ends of a rod-shaped member, and pins that are supported by the holding body and inserted into bone.
The one support body includes a clamp that holds one end side of the three or more pins and extends in a direction substantially orthogonal to the axial direction of the rod-shaped member ,
The pin held by the clamp is made of a thin titanium alloy having a diameter of approximately 1.6 mm to 2.0 mm and a length of approximately 100 mm to 150 mm. On the other hand, it is possible to fix the bone fragment by inserting each pin from multiple directions, and even if the pin is inserted elastically into the bone fragment from the other direction, one end side of the clamp It is possible to hold
[0006]
The small pin has a total strength equal to or greater than that of the large pin. Since it has a small diameter, it can be inserted even when the bone fragment is small, and it is easily elastically deformed even when driven in multiple directions, so it can be easily set in the clamp. Therefore, it is possible to hold the clamp without setting a precise angle with the drill guide.
[0007]
When the diaphyseal end of a radius or ulna breaks into fractures, a small pin is inserted and fixed to the crushed trunk end from multiple directions to reduce the joint surface. After setting the thin pin on the clamp, the rod-shaped member is stretched to correct the wrist joint. Since the rod-shaped member can be expanded and contracted and is connected to at least one support by a universal joint, reduction in all directions can be performed. Since 3 to 6 thin pins are used, it is desirable that the clamps are provided in two stages, and the thin pins are made of a titanium alloy having a diameter of approximately 1.6 mm to 2.0 mm.
[0008]
The clamp of the external fixator according to claim 2 is provided with a clamping surface that alternately protrudes protrusions that are substantially orthogonal to the insertion direction of the thin pin. The small-diameter pin can be clamped and fixed at an arbitrary position and angle between opposing ridges, and can be fixed at an arbitrary angle without causing excessive bending of the pin.
[0009]
The clamp of the external fixator according to claim 3 has an engaging portion of a ball joint for connecting the rod-like member so as to be rotatable about 90 degrees in a plane substantially orthogonal to the pin insertion direction. And the mutual insertion plane of the pins held by the pair of supports can be changed to about 90 degrees. As a result, it can be used to fix the wrist joint from the upper surface.
[0010]
The rod-shaped member of the external fixator according to claim 4, a cylindrical body fixed to the support, a shaft with a ball joint that is slidably inserted into the cylindrical body from the front end, and a female screw is threaded on the insertion side, A length adjusting bolt that is screwed into the female screw and fits the head portion to the rear end of the cylindrical body is provided. The total length of the rod-shaped member can be finely adjusted by turning the length adjusting bolt.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view of an external fixator of the present invention, and FIG. 2 is a cross-sectional view showing a II-II cross section of FIG. The external fixator 1 includes a rod-shaped member 2, a pair of supports 3 and 4 disposed at both ends thereof, two large-diameter pins 5 held on one support 3, and the other support 4. Three or more small-diameter pins 6 are held.
[0012]
The support 3 is composed of two sandwiching plates 3 a and 3 a that hold the large-diameter pin 5 and a fastening screw 3 b, and is attached to one end of the rod-like member 2. The rod-shaped member 2 has a shaft 2a with a ball joint that is connected to the other support body 4 by a universal joint, and a cylindrical body 2b into which the mounting shaft 2a is inserted into one support body 3. A long hole 2c is formed in the cylindrical body 2b, and a fixing screw 2d screwed to the shaft 2a is slidably provided. When adjusting the overall length of the rod-shaped member 2, the fixing screw 2d is loosened, the shaft 2a is moved along the long hole 2c, and tightened at a predetermined position.
[0013]
The support 4 is opposed to the three clamping plates of the upper plate 4a, the middle plate 4b, and the lower plate 4c that sandwich the small-diameter pin 6, the fastening screws 4d, and the protruding portion 4e of the middle plate 4b. A holding plate 4f that is disposed and clamps the ball joint 2e and a fastening screw 4g thereof are provided. The thin pin 6 is made of a titanium alloy having a diameter of approximately 1.6 mm to 2.0 mm and a length of 100 mm to 150 mm, and can be easily elastically deformed. The plurality of holding grooves 4h provided in two stages between the three clamping plates. Select one of these and set it.
[0014]
Next, an example of use of the external fixator 1 for wrist joint fracture will be described with reference to FIG. FIG. 3 is a plan view of a skeleton to which the external fixator is attached. When the diaphysis 7a of the arm radius 7 and the diaphysis 8a of the ulna 8 are crushed, the small pin 6 is inserted into the crushed diaphysis 7a, 8a from multiple directions and fixed. Reduce the surface. On the other hand, the large-diameter pin 5 is inserted into the distal portion of the radius using a drill guide (not shown) and fixed with the support 3.
[0015]
Three to six small-diameter pins 6 are used. However, since they have elasticity, they can be easily accommodated in the holding grooves 4h of the support 4 even if the direction of insertion with respect to the bone fragments caused by the fractures varies. Further, as shown in FIG. 3, when the small-diameter pin 6 is inserted from the metaphysis 7a of the radius 7 to the metaphysis 8a of the ulna 8, a push-up effect of the fracture site can be expected by the elastic force. After the small-diameter pin 6 is set on the support 4, the rod-shaped member 2 is appropriately extended to correct the wrist joint.
[0016]
Next, an external fixator according to another embodiment will be described with reference to FIGS. 4 is a side view of an external fixator of another embodiment, FIG. 5 is a cross-sectional view showing a VV cross section of FIG. 4, and FIG. 6 is a plan view of a clamp portion of the external fixator. The clamp 14 serving as a support for the external fixator 11 also includes three clamping plates, an upper plate 14a, an intermediate plate 14b, and a lower plate 14c, which sandwich the small-diameter pin 16, and fastening screws 14d and an intermediate plate 14b. It has a holding plate 14f disposed opposite to the projecting portion 14e and holding the ball joint 12e of the rod-like member 12 and its fastening screw 14g.
[0017]
Holding grooves 14h are formed at opposing positions on the upper surface of the lower plate 14c and the lower surface of the middle plate 14b, and protrusions 14i and 14j are alternately provided on the lower surface of the upper plate 14a and the upper surface of the middle plate 14b. As shown in FIG. 6, the small-diameter pin 16 sandwiched between the protrusions 14i and 14j substantially orthogonal to the insertion direction can be sandwiched and fixed at an arbitrary position and angle. That is, unlike the case where the pin is accommodated in the holding groove 14h, the pin can be fixed at an arbitrary angle without applying an excessive bending force to the pin.
[0018]
Further, the protruding portion 14e of the intermediate plate 14b is provided with a notch 14k into which the shaft 12a of the rod-like member 12 can enter during rotation. As a result, the external fixator 11 can be fixed from the upper surface of the wrist joint as shown in FIG. That is, the clamp 14 is fixed in parallel with the diaphysis end 17a of the radius 17 while the support 13 that accommodates the large-diameter pin is fixed in parallel with the distal portion of the radius.
[0019]
Next, an external fixator according to another embodiment will be described with reference to FIG. The rod-like member 22 of the external fixator 21 of this embodiment includes a shaft 22a with a ball joint that is connected to a support 24 that sandwiches a small-diameter pin by a universal joint, and a cylinder that is fixed to a support 23 that accommodates a large-diameter pin. The body 22b and the length adjusting bolt 22c for adjusting the entire length of the rod-shaped member 22 are provided. The rear end of the shaft 22a has an outer diameter that can be slidably inserted from the front end of the cylindrical body 22b. A female screw 22d is threaded on the insertion side and a bolt 22c is screwed.
[0020]
The head portion 22e of the bolt 22c is fitted to the rear end of the cylindrical body 22b, and the length of the rod-like member 22 is finely adjusted by turning this with a screwdriver or the like.
[0021]
【The invention's effect】
As described above, the external fixator of the present invention has a small diameter that can be inserted into three or more bone fragments caused by the fracture of the wrist joint and can be held by the clamp while being elastically deformed. Because it uses a pin, it can be inserted even when the bone fragment is small, and it can be easily set in the clamp because it is easily elastically deformed even when driven from multiple directions, and it is fixed externally without straddling the wrist joint Since the instrument can be worn, the motor function of the fingers is not impaired. In addition, a small pin can be held by a clamp without setting a precise angle with a drill guide.
[0022]
Since the clamp of the external fixator according to the second aspect is provided with a clamping surface for alternately projecting the ridges, the clamp can be clamped and fixed at an arbitrary position and angle without causing excessive bending of the thin pin. The clamp of the external fixator according to claim 3 has a ball joint engaging portion for connecting the rod-like member so as to be able to rotate about 90 degrees in a plane substantially orthogonal to the pin insertion direction. Fixing from is also possible. Since the length adjusting bolt is screwed onto the shaft that is slidably inserted into the cylinder, the rod-shaped member of the external fixator according to claim 4 can be easily finely adjusted.
[0023]
[Brief description of the drawings]
FIG. 1 is a plan view of an external fixator.
FIG. 2 is a cross-sectional view showing a II-II cross section of FIG.
FIG. 3 is a plan view of a skeleton to which an external fixator is attached.
FIG. 4 is a side view of an external fixator according to another embodiment.
5 is a cross-sectional view showing a VV cross section of FIG. 4; FIG.
FIG. 6 is a plan view of a clamp portion of an external fixator according to another embodiment.
FIG. 7 is a plan view of a skeleton to which an external fixator according to another embodiment is mounted.
FIG. 8 is a cross-sectional view of an external fixator according to another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 External fixator 2 Rod-shaped member 3 Support body 4 Support body 5 Large diameter pin 6 Small diameter pin

Claims (5)

In an external fixator having a pair of supports disposed at both ends of a rod-shaped member, and a pin supported by the support and inserted into a bone,
The one support body includes a clamp that holds one end side of the three or more pins and extends in a direction substantially orthogonal to the axial direction of the rod-shaped member ,
The pin held by the clamp is made of a thin titanium alloy having a diameter of approximately 1.6 mm to 2.0 mm and a length of approximately 100 mm to 150 mm. On the other hand, it is possible to fix the bone fragment by inserting each pin from multiple directions, and even if the pin is inserted elastically into the bone fragment from the other direction, one end side of the clamp External fixator characterized in that it can be held . The external fixator according to claim 1, wherein the clamp includes a clamping surface that alternately protrudes protrusions that are substantially orthogonal to the insertion direction of the thin pin. 2. The external fixation according to claim 1, wherein the clamp has an engaging portion of a ball joint that connects the rod-like member so as to be rotatable about 90 degrees in a plane substantially orthogonal to the pin insertion direction. vessel. The rod-shaped member includes a cylindrical body that is fixed to the support body, a shaft with a ball joint that is slidably inserted into the cylindrical body from the front end, and a female screw is threaded on the insertion side, and is screwed into the female screw. The external fixator according to claim 1, further comprising a length adjusting bolt that fits a head portion to a rear end of the cylindrical body. The external fixator according to claim 1, wherein the clamp has a plurality of pin holding grooves in two stages.

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