JP3740640B2 - 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]
In the case of an unstable fracture or an intra-articular fracture, a surgical treatment is required for a fracture of a wrist joint, and a typical treatment method includes an external fixator. In general, the external fixator has a rod-shaped member disposed along the fracture portion, a pair of clamps disposed at both ends thereof, and a plurality of pins whose one ends are fixed at right angles to the clamps, The bone is fixed by inserting the other end of the pin into the bone of the fracture. 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]
For this reason, an external fixator has been developed that enables early rehabilitation and does not straddle the wrist joint for the purpose of simplifying the surgical technique. This external fixator uses a small-diameter pin that can be inserted into a bone fragment while elastically deforming. For example, when treating unstable distal radius fractures, the proximal pin has a diameter. Although a 3 mm pin was used, a distal pin having a diameter of 1.8 mm or 2 mm was appropriately selected depending on the case. If such a thin distal pin is used, it can be used even if the space of the distal bone piece is small, and since it bends, it is possible to have the action of pulling up the joint surface with anti-tension. There were also advantages such as prevention of shortening. In addition, since the clamp that pinches the small-diameter pin is connected to the rod-like member via the ball joint, it can be reduced at any angle, and the rod-like member has a mechanism that can adjust its length. As a result, the degree of traction could be changed arbitrarily.
[0005]
However, even with such an external fixator that does not straddle the wrist joint, the thin pin inserted into the fracture site is generally limited to one direction. Could not prevent the fixed wrist joint from moving in the dorsal or palmar direction. Also, if a ulna fracture occurred at the same time as the flexion, another fixing device was necessary.
[0006]
This invention solves the above-mentioned problem, can insert a pin from a plurality of directions with respect to a wrist joint fracture, can prevent the movement of the fixed bone, can be firmly fixed on the surface, and can be used for fracture of the ulna. An object of the present invention is to provide an external fixator that can be fixed separately from a fracture of a flexure.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, an external fixator of the present invention sandwiches three or more small-diameter pins that can be inserted into three or more pins while elastically deforming a bone fragment caused by a fracture of a wrist joint portion. In the external fixator having one clamp rotatably connected to a ball joint provided at one end of a rod-shaped member and another clamp connected to the other end of the rod-shaped member while pinching a pin inserted into a bone. The clamp has a plurality of clamping surfaces in a plane substantially perpendicular to the axial direction of the rod-like member, and each clamping surface can hold a plurality of small-diameter pins and can be inserted into bone fragments from different directions. The other clamp is rotatably connected to a ball joint provided at the other end of the rod-shaped member.
[0008]
One clamp has a structure in which independent clamping plates are provided at both ends of an arc-shaped plate having a central angle of 90 ° or more, for example, and an engaging portion of a ball joint of a rod-shaped member is provided at the center of the arc-shaped plate. An uneven surface is formed on the opposing surfaces of the arc-shaped plate member and the sandwich plate so that the small-diameter pin can be securely held. Therefore, the direction of the thin pin held by one clamping plate is substantially the same direction, but a slight angle change is possible.
[0009]
When the diaphyseal end of the bony bone is crushed, a thin pin is inserted into the crushed diaphyseal end from about 90 ° different directions on the flex side and the dorsal side to fix 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 uses ball joints at both ends, reduction in all directions can be performed. It is desirable to arrange about three small diameter pins with respect to one clamping plate.
[0010]
Also, if a fracture of the distal ulna fracture has occurred, the thin pin held on one clamping plate is the fractured part of the radius, and the small pin held on the other clamping plate is the fractured part of the ulna Insert and fix from the back side.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a front view of an external fixator of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a right side view thereof, and FIG. 4 is a cross-sectional view of a rod-shaped member. The external fixator 1 includes a rod-shaped member 2, a pair of clamps 3 and 4 disposed at front and rear ends thereof, two large-diameter pins 5 held by these inner and rear clamps 3, and a front clamp 4. A plurality of small-diameter pins 6 are held.
[0012]
The rear clamp 3 is disposed opposite to the two clamping plates 3a and 3b that hold the large-diameter pin 5, the fastening screws 3c that are screwed to the clamping plates 3a, and the protruding portion 3d of the clamping plate 3a. A holding plate 3e for clamping the rear ball joint 2a and its fastening screw 3f are provided. The rod-like member 2 has a shaft 2b with a ball joint that is connected to the rear clamp 3 by a universal joint as described above, and a cylindrical body 2c that engages with the front clamp 4 and inserts the shaft 2b.
[0013]
As shown in FIG. 4, a groove 2d is formed in the axial direction of the shaft 2b, and a tip of a fixing screw 2e screwed to the cylindrical body 2c is brought into contact with the groove 2d. When adjusting the overall length of the rod-shaped member 2, the fixing screw 2e is loosened and the shaft 2b is moved to an arbitrary position, and then screwed and fixed.
[0014]
As shown in FIG. 3, the front clamp 4 is formed with stepped portions 4b and 4c at both ends of an arc-shaped substrate 4a having a central angle exceeding 90 °, and superimposes small arc plates 4d and 4e, respectively, and is screwed to them. Fastening screws 4f and 4g are provided. An uneven surface (not shown) is formed on the opposing surfaces of the stepped portions 4b and 4c and the small circular arc plates 4d and 4e so that the small-diameter pin 6 can be securely held. 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. Moreover, the fixing force is improved by providing a screw thread at the tip of the small diameter pin 6.
[0015]
A holding plate 4h and its fastening screw 4i are provided in the center of the arc-shaped substrate 4a, and a front ball joint 2f protruding from the end of the cylindrical body 2b is sandwiched. In this way, the external fixator 1 uses the ball joints 2a and 2f at both ends of the rod-like member 2, so that even when the large-diameter pin 5 and the small-diameter pin 6 are inserted at a wide angle, it is retained. Can be reduced in all directions.
[0016]
Next, an example of using the external fixator 1 for a wrist joint fracture will be described with reference to FIG. FIG. 5 is a plan view of a skeleton to which the external fixator is attached. When the diaphyseal end portion 7a of the arm radius 7 is crushed, a small pin 6 sandwiched by the side of the anterior clamp 4 is inserted into the crushed diaphyseal end portion 7a from the flexible side, The small-diameter pin 6 sandwiched between the upper small arc plate 4e and the arc-shaped substrate 4a is inserted and fixed from the back side to reduce the joint 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 by the rear clamp 3.
[0017]
In this way, pin insertion can be performed from the flexion side and the dorsal side with respect to the wrist joint fracture, and as a result, firm surface fixation is achieved. Moreover, since it is lifted and fixed from the back side, it can prevent that the reduced wrist joint part moves to the back side or the palm side direction. Further, since the small-diameter pin 6 is bent, it is possible to have an action of pulling up the joint surface by the counter-tension, and the shortening of the flexure 7 can be prevented.
[0018]
Next, another use example of the external fixator will be described with reference to FIG. FIG. 6 is a plan view of the skeleton to which the external fixator is attached when the ulnar distal end fracture is combined. In the case where a crushed fracture has occurred at the diaphyseal end portion 7a of the radius 7 and the diaphyseal end portion 8a of the ulna 8, the small-diameter pin 6 held by one small circular arc plate 4d is provided at the fracture site of the radius 7 or The small-diameter pins 6 held by the other small circular arc plates 4e are inserted into the fracture site of the ulna 8 from the back side and fixed.
[0019]
【The invention's effect】
As described above, the external fixator according to the present invention is provided with a clamp having a plurality of clamping surfaces on a plane substantially orthogonal to the axial direction of the rod-shaped member, so that the pin can be pinned from a plurality of directions with respect to the wrist joint fracture. Can be inserted, and can prevent the movement of the fixed bone, and can be firmly fixed on the surface. Can be fixed. Moreover, since the rod-shaped member can be expanded and contracted and uses ball joints at both ends, reduction in all directions can be performed. Further, since the small-diameter pin can be held by the clamp while being elastically deformed, it can be inserted even when the bone fragment is small and can be easily set in the clamp.
[Brief description of the drawings]
FIG. 1 is a front view of an external fixator.
FIG. 2 is a plan view of the external fixator.
FIG. 3 is a right side view of the external fixator.
FIG. 4 is a cross-sectional view of a rod-shaped member.
FIG. 5 is a plan view of a skeleton to which an external fixator is attached.
FIG. 6 is a plan view of a skeleton to which an external fixator is attached to a radius and a distal ulna fracture.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 External fixator 2 Rod-shaped member 3 Back clamp 4 Front clamp 4a Arc-shaped board | substrate 4d Small arc board 4e Small arc board 5 Large diameter pin 6 Small diameter pin

Claims (1)

A small-diameter pin that can be inserted into three or more pins while elastically deforming a bone fragment caused by a fracture of a wrist joint, and a ball joint provided at one end of a rod-like member that is pinched and rotatably connected The external clamp having a pin inserted into the bone and connected to the other end of the rod-shaped member, the one clamp is in a plane substantially perpendicular to the axial direction of the rod-shaped member. It has a plurality of clamping surfaces, and each clamping surface can be inserted into a bone fragment from different directions while holding a plurality of small-diameter pins, and the other clamp is provided at the other end of the rod-shaped member An external fixator that is pivotably connected to a ball joint.

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