JPH0938121A - Femur head adapter and artificial bone head replacement using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily and rapidly execute the replacement of the artificial marrow without removing an intramedullary nail by forming a main body having a prescribed size and shape of a high-strength metal, such as titanium alloy, providing the neck of its upper section with a aspherical head and a longitudinal hole to be inserted with the existing intramedullary needle and a bolt mounting hole. SOLUTION: The femur head adapter 3 is formed of the main body 3a mounted with the spherical head 3c and bolt 3b and is brought into sliding contact with the socket of the acetabulum. This main body 3a is formed of the titanium alloy, etc., having high corrosion resistance and strength and have the coefft. of elasticity approximate to the coefft. of elasticity of the human bone. The sectional shape and size perpendicular to the axial line are approximated to those of the trochanter of the femur. A neck 30 is formed in correspondence to the collum femoris. The main body 3a is provided with the longitudinal hole 33 to be inserted with the top end region of the existing intramedullary needle. The main body is provided with the inclined bolt mounting hole 34 so as to intersect with the longitudinal hole 33 to prevent the separation of the main body 3a from the intramedullary needle cooperatively with the bolt 3b or the rotation thereof.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a femoral head adapter adapted to various intramedullary nails.

[0002]

2. Description of the Related Art When a femoral shaft, subtrochanter, distal stenosis, or the like is fractured, the bone marrow cavity is generally reamed and broached from the apex of the femur, and the bone marrow cavity is elongated. Insert a simple intramedullary nail, insert it into the bone through the screw so that it is almost perpendicular to the lower end of the intramedullary nail (distal part), and fix it to the bone at the upper end (proximal part). The method is to penetrate the screw so as to intersect with and to screw it to the head or trochanter. However, if a person who has undergone such an operation subsequently has a crush fracture or a complicated fracture around the neck of the femur and cannot repair it, an artificial head replacement surgery is necessary. Conventionally, this artificial head replacement technique has already been performed using an artificial head in which a spherical head 81 is attached to the top of a curved stem 8 that becomes narrower toward the bottom via a neck 80, as shown in FIG. A method has been adopted in which the existing intramedullary nail is pulled out, the neck 1e is obliquely cut, and the curved stem 8 is fixed to the bone marrow cavity 11 from the neck 1e.

However, in this method, the bolt that penetrates the lower part of the intramedullary nail must be removed to remove the intramedullary nail during the operation. In the operation, the bolt and the intramedullary nail are fixed to the bone. As a result, the operation becomes very large, and it takes time and labor and the post-operative patient suffers a lot. Moreover, since the intramedullary nail as a reinforcing material that has been longitudinally passed through the femur is eliminated, the strength of the diaphyseal portion is reduced. Therefore, the diaphysis is easily broken due to a fall or the like, which necessitates a new operation, or even an old man cannot even perform the operation, which makes walking impossible. Further, in the prior art, there is a problem that the bone union cannot be applied before the treatment of the bone fracture is completed, since the bone fusion is an essential condition.

[0004]

SUMMARY OF THE INVENTION The present invention was made by research in order to solve the above-mentioned problems, and the purpose thereof is to construct it without pulling out an intramedullary nail. Even before the treatment of intramedullary nails is completed, a simple femoral artificial head replacement structure and an artificial head replacement method using the same can be easily and quickly used while effectively utilizing this. To provide.

[0005]

To achieve the above object, the present invention comprises a body and a bolt made of a metal having a high strength such as a titanium alloy or a cobalt chromium alloy, the body being a trochanteric region of a femur. Has a thickness and shape corresponding to, a spherical head is provided on the neck of the upper portion, and a vertical hole for fitting the upper end region of the existing intramedullary nail is formed in the main body, and intersects with this vertical hole. In the direction, a bolt attachment hole having an angle corresponding to the oblique hole provided at the upper end of the existing intramedullary nail and having a female screw in the tip region is provided.

In addition to the main body and the bolt, the present invention has one or more spacers to be interposed between the lower surface of the main body and the resection end face obtained by cutting the trochanteric region of the femur. Including cases. The spacer is made of a metal having high strength such as a titanium alloy or a cobalt chrome alloy in a thickness and shape corresponding to the trochanteric region of the femur, and has a through hole through which the upper end of the existing intramedullary nail penetrates in the thickness direction. It is preferable to have a rotation stopping portion on the surface.

The artificial head replacement surgery according to the present invention is applied when the neck of the femur is fractured beyond repair during treatment with an existing nail. Using the femoral head adapter described above as an artificial femoral head means, so as to expose the upper end region of the existing intramedullary nail, the trochanter region of the femur is cut into bone, and in this state, the upper end region of the existing intramedullary nail is cut. The vertical hole of the main body is fitted over the bolt, and the bolt is tightened from the bolt mounting hole through the oblique hole at the upper end of the existing intramedullary nail. In this way, the bolt penetrates the oblique hole of the existing intramedullary nail and is screwed into the female screw, and the existing intramedullary nail securely prevents the body from rotating and coming off. Therefore, the artificial bone head can be replaced by a simple operation, and the existing intramedullary nail is not pulled out, so that its reinforcing effect can be fully utilized.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a bone head replacement state to which the present invention is applied. In FIG. 1, reference numeral 1 denotes a femur, and a proximal portion, that is, a trochanteric region, is excised by a required length. 10 is the cut end face. Reference numeral 2 denotes an existing intramedullary nail that is inserted and embedded in the femur 1, and an upper end portion 20 thereof projects above the resection end surface 10. Reference numeral 3 denotes a femoral head adapter according to the present invention, which is attached with the upper end portion 20 of the intramedullary nail 2 as a core. 4 is an acetabulum.

The intramedullary nail 2 is made of a metal material having a high corrosion resistance, a high strength and an elastic modulus close to that of a human bone, such as a titanium alloy or a cobalt chromium alloy. As can be seen from FIGS. 1 and 8 (a), the intramedullary nail 2 is originally inserted into the bone marrow cavity 11 from the trochanter (proximal portion) 1a of the femur 1 to the distal portion 1b. , The lower end 2 corresponding to the distal portion 1b
1, transverse holes 22 and 22 are provided so as to be orthogonal to the axis, and the distal portion 1b is formed so as to penetrate these transverse holes 22 and 22.
Bolts 5 and 5 are screwed in and fixed to. When the bone head is normal, the intramedullary nail 2 has an upper end 2 as shown in FIG. 8 (a).
0 is located so as to penetrate the trochanter 1a, and the upper end portion 20
For example, an oblique hole 23 having a neck angle of about 130 ° and a anteversion angle of about 10 ° is formed, and a bolt 6 is inserted from below the trochanter through the oblique hole 23.
Is screwed so as to reach the head 1d through the neck 1c.

2 and 3 show a first embodiment of the femoral head adapter 3 according to the present invention as a single body. In the first embodiment, the femoral head adapter 3 includes a main body 3a to which a spherical (including bipolar type) head 3c is attached,
It has a bolt 3b, and in this embodiment, a socket (cup) 3d which is in sliding contact with the head 3c is attached to the acetabulum 4. The main body 3a is made of a columnar block such as a metal material having a high corrosion resistance, a high strength, and an elastic coefficient close to that of a human bone, such as a titanium alloy or a cobalt chromium alloy.
The cross-sectional shape and thickness at right angles to the axis are made to be similar to that of the trochanter 1a of the femur 1, and a flat seat surface 32 to be contacted with the resection end surface 10 of the femur 1 is formed at the lower end. Has been done. A neck 30 extending obliquely upward at an angle similar to the neck 30 of the femur 1 is integrally formed on the main body 3a so that the head 3c is fixed to the neck 30. Has become.

Further, the main body 3a is provided with a vertical hole 33 which opens to the seat surface 32. The vertical hole 33 is used for fitting the upper end portion 20 of the intramedullary nail 2 therein.
The seating surface 32 has a depth dimension that allows the seating surface 32 to come into contact with the cut end surface 10 when 0 is fitted therein. However, the vertical hole 33 does not necessarily have to be a blind hole, and may be a through hole. In this case, a plug may be attached to the through hole and brought into contact with the top surface of the upper end portion 20. The cross-sectional shape of the vertical hole 33 at right angles to the axis may be a simple circular hole, or may be a cross-sectional shape corresponding to the cross-sectional shape at right angles to the axis of the upper end portion 20 (eg, square, grooved variant, groove and slot variant, etc.). May be. The hole diameter of the vertical hole 33 may be the same as that of the upper end portion 20, but may be an appropriately enlarged size. Upper end 2
If there is a significant difference from the zero dimension, the inner diameter
Use an insert sleeve that matches
3 and the upper end portion 20 may be internally fitted to the insert sleeve.

Further, an inclined bolt mounting hole 34 is formed in the main body 3a so as to intersect the vertical hole 33. The bolt mounting hole 34 is for cooperating with the bolt 3b to prevent the main body 3a from coming off so as not to be separated from the intramedullary nail 2, and to prevent rotation about the intramedullary nail 2. The inner nail 2 is substantially concentric with the oblique hole 23 provided at the upper end portion 20 of the inner nail 2, and thus faces the neck 30 in the axial direction. The bolt attachment hole 34 has an internal thread 340 in a region past the upper end 20 of the intramedullary nail 2.
A counterbore 34 for contacting the head of the bolt 3b is provided on the opening side.
1 is provided. The bolt 3b is made of the same material as that of the main body 3a, and has a male screw 3 which is screwed into the female screw 340 at the tip thereof.
7 are provided.

The head 3c has high corrosion resistance and high strength,
Moreover, it is made of a metal material having an elastic modulus close to that of a human bone, such as a titanium alloy or a cobalt chromium alloy. Socket 3
Reference numeral d denotes a hemispherical metallic cup or outer shell 35 fixed to the acetabulum 4 with or without screws, and an insert 36 made of a polymer material fitted in the outer shell 35. 36 to the head 3
c can be freely rotated.

The socket 3d is used when the acetabulum 4 is damaged, but when the acetabulum 4 is healthy, the socket 3d is replaced by a hemispherical shape as shown in FIG. 4, instead of the socket 3d. Socket head 3 in which a metal cup or outer shell 35 'is integrated with an insert 36' made of a polymer material
Alternatively, the head 3c may be slidably fitted to the d ', and the socket head 3d' may be internally fitted to the acetabulum 4.

5 and 6 show a second embodiment of the femoral head adapter 3 of the present invention. In this embodiment, the resection end surface 10 and the seat surface 3 of the main body 3a are selected depending on the condition of the osteotomy of the femur 1.
When a gap is created between the femoral head adapter 3 and the femoral head adapter 3
The main body 3a to which the spherical (including bipolar) head 3c is attached is adapted so that it can be easily adapted without preparing a plurality of different lengths.
And one or more spacers 3e in addition to the bolts 3b. In this example, three spacers 3e are used. Each spacer 3e is made of a plate made of a metal material having high corrosion resistance, high strength, and an elastic modulus close to that of a human bone, such as a titanium alloy or a cobalt chromium alloy.
The cross-sectional shape and thickness at right angles to the axis are made to be similar to that of the trochanter 1a of the femur 1. Then, each spacer 3e is provided with a through hole 38 having the same diameter and shape as the upper end portion 20 of the intramedullary nail 2 in the thickness direction, and rotation preventing portions 39, 39 'are provided on the upper and lower surfaces outside the through hole 38. It is provided.

In this embodiment, the rotation preventing portion 39 on the upper surface is 2
It is configured as a protrusion above the location, and the rotation stopper 3 on the lower surface
9'is formed as two or more concave portions corresponding to the protrusions, and the rotation preventing portions 39, 3 are formed when the spacer 3e is overlapped.
The 9's are engaged with each other. Of course, the anti-rotation portion 39 on the upper surface is made into a concave portion, and the anti-rotation portion 39 'on the lower surface is provided.
May be a protrusion. The seat 32 of the main body 3a is provided with a detent portion 320 composed of a recess or a protrusion at a position corresponding to the detent portion 39 of the spacer 3e. The lowest spacer 3e in contact with the cut end face 10
May have a flat bottom surface. Preferably, several types of spacers 3e having different thicknesses are prepared. Since other configurations are the same as those of the first embodiment, the same parts or the same parts are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 7 shows another embodiment of the femoral head adapter 3 of the present invention. In this embodiment, two bolt mounting holes 34 are formed substantially in parallel. Since other structures are the same as those in the first and second embodiments, the same parts and portions are designated by the same reference numerals and the description thereof will be omitted. In the illustrated example, since the upper end portion 20 of the intramedullary nail 2 has a diameter larger than that, a gap is formed between the portion directly below the upper end portion 20 and the vertical hole 33. Fill the bone cement to eliminate the gap. Of course, the upper end portion 20 of the intramedullary nail 2 may have the same diameter as the lower portion, and in this case, no gap is formed.

[0018]

The operation of the artificial head replacement using the femoral head adapter 3 of the first embodiment will be described. As shown in FIG. 8A, the circumference of the femoral neck, for example, the head 1d is indicated by s. When the bone becomes fractured and cannot be repaired, the bolt 6 penetrating the oblique hole 23 of the upper end portion 20 of the intramedullary nail 2 is removed, and the bone is cut to a portion below the trochanter 1a. To do. The bone cutting may be adjusted so that the vertical hole 33 of the main body 3a is sufficiently fitted to the upper end portion 20 of the intramedullary nail 2 and the oblique hole 23 and the bolt mounting hole 34 are concentrically positioned. It can be easily confirmed by inserting the pilot pin into the bolt mounting hole 34. Of course, if necessary, the cut end face 10 is finely adjusted by grinding or polishing.

Due to this bone cutting, the upper end portion 20 of the intramedullary nail 2 projects from the cut end surface 10 as shown in FIG. 8 (a). Next, the entrance of the vertical hole 33 of the main body 3a is arranged on the top of the upper end 20 of the intramedullary nail 2, and the main body 3a is pushed. As a result, the main body 3a is externally fitted using the upper end portion 20 as a guide, and the seat surface 32 at the lower end contacts the cut end surface 10. At this time, the upper end 2
The slant hole 23 and the bolt mounting hole 34 are concentric. This is because if there is a gap between the vertical hole 33 and the upper end portion 20, it is sufficient to rotate the main body 3a in the circumferential direction after the external fitting, and if there is no gap between the vertical hole 33 and the upper end portion 20 or it cannot rotate due to the sectional shape. May be positioned in the circumferential direction when the pushing of the main body 3a is started.

At this step, the state shown in FIG. 8B is obtained. Then, after that, the bolt 3b may be inserted into the bolt mounting hole 34 as shown in FIG. 8C, inserted through the oblique hole 23 of the upper end portion 20, and the male screw 37 may be screwed into the female screw 340 and tightened. As a result, the main body 3a is prevented from coming off and prevented from rotating by the intramedullary nail 2 and the bolt 3b. On the other hand, in the case where the acetabulum 4 is damaged, if the acetabulum 4 is reamed, the cup or outer shell 35 of the socket 3d is driven and fixed, and the acetabulum 4 is sized according to the size of the patient's head. Decide the insert and head,
The insert 36 is driven into the cup or outer shell 35 to fix the head 3c to the neck 30 of the main body 3a. Then, insert the head 3c into the insert 36 of the socket 3d.
It may be fitted to. Thus, the artificial head as shown in FIG. 1 is formed. When the acetabulum 4 is healthy, a socket head 3d 'is used, the head 3c is slidably fitted to the socket head 3d', and the reamed acetabulum 4 has a socket head 3d '.
Can be fitted inside.

The second embodiment is suitable for the case where the bone cutting length up to the site under the trochanter 1a is increased due to the condition of the affected area or the like. That is, in the first embodiment, in such a case, it is necessary to prepare the main body 3a having several kinds of lengths and select and use it appropriately. However, according to the second embodiment, since the spacer 3e is provided, even if there is a gap between the seating surface 32 of the main body 3a and the cut end face 10, the number of the spacers 3e corresponding to the gap is passed. If the upper end portion 20 is sequentially fitted via 38, the lowest one is the cut end face 1
0 is abutted, and the one above it is non-rotatably laminated via the detents 39, 39 ', and the seat surface 32 of the main body 3a is superposed on the uppermost one via the detent 320. Therefore, the oblique hole 23 of the upper end portion 20 and the bolt mounting hole 34 can be easily aligned concentrically.

In any of the embodiments, the operation method described above makes the work extremely easy. That is, firstly, since the intramedullary nail 2 is not removed from the femur 1, it is not necessary to remove the bolts 5 and 5 at the distal portion 1b, and therefore the incision of the distal portion 1b is also unnecessary. Also,
No large force is required to pull out the intramedullary nail 2 fixed to the medullary cavity 11. Secondly, the steps of manufacturing a pilot hole, milling, and broaching, which are required when using a conventional stem-type artificial head, are not required, and this aspect is also simple. Thirdly, since the upper end portion 20 of the intramedullary nail 2 can function as a guide or a centering tool for the artificial bone head 3, alignment and attachment are easy. In addition, since the existing intramedullary nail 2 is inserted in such a length as to reach the distal portion of the femur 1 in this way, the bone weakening does not occur due to the artificial head replacement surgery, and the operation is sufficient. A strong reinforcing effect can be realized. Further, since the upper end portion 20 of the intramedullary nail 2 simultaneously functions as the core of the main body 3a,
The artificial head can be made more stable and stronger than the stem-type artificial head.

[0023]

As described above, according to claim 1 of the present invention, a metal having high strength such as titanium alloy or cobalt chromium alloy is formed to have a thickness and shape corresponding to the trochanteric region of the femur 1, and the upper portion is formed. A body 3a having a spherical head 3c and a bolt 3b are provided, and the existing intramedullary nail 2 is attached to the body 3a.
A vertical hole 33 for fitting the upper end portion 20 of the inside is formed, and an angle corresponding to the oblique hole 23 provided in the upper end portion 20 of the existing intramedullary nail 2 is formed in a direction intersecting with the vertical hole 33. Since the bolt attachment hole 34 having the female screw 340 is provided in the distal end region, it is possible to perform artificial femoral head replacement of the femur by a simple operation, and yet to utilize the existing intramedullary nail without removing it, so that the bone is not weakened. An excellent effect that the reinforcing effect can be sufficiently exerted is obtained. According to the second aspect, since the spacer 3e is provided, even if the cut length of the femur 1 becomes excessive, it is possible to easily cope with it without preparing various types of main bodies 3a having different lengths. The excellent effect of being able to do is obtained. According to the fourth aspect, it is not necessary that the bone fusion is completed, and an excellent effect that an appropriate artificial head replacement can be performed even before the treatment with the applied intramedullary nail is completed is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a femur to which the present invention is applied.

FIG. 2 is a vertical sectional side view showing a first embodiment of the femoral head adapter according to the present invention.

3 is a cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a partial sectional view showing a femur to which the present invention is applied.

FIG. 5 is a vertical sectional side view showing a second embodiment of the femoral head adapter according to the present invention.

FIG. 6 is an explanatory diagram of a spacer according to a second embodiment.

FIG. 7 is a cross-sectional view showing another example of the femoral head adapter of the present invention.

FIG. 8 is a cross-sectional view showing the artificial head replacement process when the first embodiment is applied.

FIG. 9 is a cross-sectional view showing a use state of a conventional artificial head.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE CHARACTERS 1 femur 1a trochanter 1d femoral head 2 intramedullary nail 3 femoral head adapter 3a of the present invention 3a body 3b bolt 3c head 3e spacer 20 upper end 33 vertical hole 34 bolt mounting hole 38 through hole 39, 39 'detent 340 female screw

Claims (4)

[Claims] 1. A body and a bolt made of a high-strength metal such as a titanium alloy or a cobalt chromium alloy, the body having a thickness and shape corresponding to a trochanteric region of a femur,
The upper part of the neck is provided with a spherical head, and a vertical hole for fitting the upper end region of the existing intramedullary nail is formed in the main body. A femoral head adapter characterized in that a bolt attachment hole having an angle corresponding to a beveled hole provided at an upper end portion and having a female screw in a tip region is provided. 2. One or more spacers to be interposed between a lower surface of the main body and a resection end surface obtained by cutting the trochanteric region of the femur, the spacers being made of titanium alloy, cobalt chrome alloy, or the like. Made of high-strength metal to a thickness and shape corresponding to the trochanteric region of the femur, with a through hole in the thickness direction through which the upper end of the existing intramedullary nail penetrates, and a detent part on the surface. The femoral head adapter according to claim 1, which includes a cap. 3. The femoral head adapter according to claim 1, which includes one having a plurality of bolt mounting holes. 4. The artificial femoral head means as an artificial femoral head means for replacing a femoral bone fractured to such a degree that the neck of the femur cannot be repaired during treatment with an existing bone nail, as an artificial femoral head means.
Using the femoral head adapter described in any one of, the trochanteric region of the femur is bone-cut to expose the upper end region of the existing intramedullary nail from the resection end face thereof, and in this state, the upper end region of the intramedullary nail is exposed. An artificial femoral head replacement technique using a femoral head adapter, characterized in that the vertical hole of the main body is fitted over the body, and the bolt is tightened from the bolt mounting hole through the oblique hole at the upper end of the existing intramedullary nail.