JPH1176259A - Joint device and joint device kit for upper end part of thigh bone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint device and a joint device kit which enables the fixing of a broken bone part accurately by arranging a structure that matches the shape of the upper end part of a thigh bone corresponding to an angle of forward torsion of the upper end part of the thigh bone to facilitate the operation of the broken upper end part of the thigh bone. SOLUTION: The axis 22X of a support hole 22a of a sleeve part 21 extends askew in the direction opposite to shifting so as to have an angle addressing a neck body and a angle addressing forward torsion after deviated horizontally by a shift range S on an extended plane 21P of the rear of the fixed plate 21 with respect to the axis 21X thereof 21. With such an arrangement, the joint device of the embodiment is made adaptive to the upper end part of the thigh bone having the angel (θ) to the neck body and the angle (ϕ) to forward torsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint and a joint set at the upper end of a femur, and more particularly to a joint structure suitable for fixing a fracture near a head or a neck at the upper end of a femur. .

[0002]

2. Description of the Related Art Conventionally, as a connector and a connector set for an upper end of a femur, a fixing plate portion configured to be fixed to an upper side surface of a femur and a sleeve portion protruding from an end of the fixing plate portion are known. And a fixed shaft for embedding in a femoral head. There are various types of such a connector set. For example, as shown in FIG. 7, a plate body 40 constituting a fixed plate portion and a groove portion 41 provided at an end of the plate body 40 are provided. A support member 42 configured to engage in a sliding manner, and a lag screw 44 that is a fixed shaft inserted into a support hole formed inside a sleeve 43 that forms a sleeve portion of the support member 42; It is composed of

FIG. 8 is a schematic view of the upper part of a femur. Above a cylindrical femoral body 10, there are a greater trochanter 11 and a lesser trochanter 12 to which muscles of the lower limb are attached. 13 and a bone head 14 are formed. Since a large stress is applied to the upper end of the illustrated femur due to the weight of a person, a fracture is often caused at the upper end of the femur, particularly in the elderly.
Above all, stress concentrates on a small cross section of the neck 13, so that a fracture line is frequently formed there.

[0004] When a fracture occurs in the neck or the like, it is necessary to fix the bone head constituting the joint between the pelvis and the bone, so it is necessary to fix the fracture part particularly firmly. When fixing a fractured part using the above-mentioned connector, the lag screw 44 is screwed from the uppermost part of the upper surface 10a of the femur, and the tip of the lag screw 44 reaches the inside of the bone head 14. In this state, the support member 42
The back surface of the plate body 40 engaged with the upper surface of the femur 10
The plate body 40 is fixed to the femur by a fixing screw which is tightly attached to a and is inserted through a plurality of fixing holes (not shown) formed in the plate body 40.

[0005]

By the way, in the conventional general joint, in order to match the shape of the upper end of the femur, the joint between the back surface of the fixing plate portion and the axis of the support hole formed in the sleeve portion. A constant inclination angle corresponding to the neck angle of the femur is provided. However, when trying to fix the fractured part of the upper end of the femur with the joint and the lag screw, there is a problem that in many cases, the joint and the lag screw do not completely match the shape of the upper end of the femur. is there.

[0006] As shown in FIG.
From the upper end of the femur to a perpendicular C parallel to the axis A of
Although the neck angle θ between the axis B indicating the direction in which the body projects and the inclination angle of the connector substantially coincides with each other, the axis B does not intersect the axis A and is twisted forward of the body. When the fixed plate portion is fixed substantially perpendicularly to the center direction F of the body in a state in which the fixed plate portion is in contact with the upper side surface 10a, the lag screw screwed along the axis B and the fixed plate portion are aligned with each other. This is because the relationship between A and the axis B is twisted by the misalignment and the anteversion angle φ.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a structure adapted to the shape of the upper end of the femur so as to correspond to the anteversion angle of the upper end of the femur. It is an object of the present invention to provide a connector and a connector set that facilitate surgery of a fracture at an upper end of a bone and can securely fix the fracture.

[0008]

According to the present invention, there is provided a fixing plate portion having a back surface in contact with an upper side surface of a femur and configured to be fixed to the upper side surface. And a support hole having an axis that projects onto an orthogonal plane that includes the axis of the fixed plate portion and that is orthogonal to the extension plane of the back surface and intersects the extension plane at a first angle, and protrudes from the extension plane. And a sleeve part configured as described above, wherein the fixing shaft is used in a state where a fixed shaft configured to be embedded in a bone is inserted through the supporting hole. Axis passes through an intersection on the extension plane shifted by a predetermined shift distance to one of both sides with respect to the axis of the fixed plate portion, and a shift direction toward the projecting direction of the sleeve portion. Is the other side Characterized in that it is configured to extend inclined at a second angle.

According to this means, the axis of the support hole having an intersection with the extension plane at a position shifted with respect to the axis of the fixed plate portion and extending at a second angle to the opposite side to the shift direction. Since it is possible to correspond to the shift amount and the anteversion angle of the femoral head when the fixing shaft is inserted and fixed in the support hole, it is possible to enhance the compatibility with the femur, The work of fixing the fracture is facilitated, and the fracture can be fixed reliably and accurately.

Here, it is preferable that the second angle is an angle in the range of 10 to 60 degrees which substantially corresponds to the anteversion angle of the femur.

According to this means, it is possible to more accurately adapt to the femur of the patient by associating the second angle with the anteversion angle of the femur in advance.

In this case, the shift distance is 1 to
It is preferably 10 mm.

According to this means, the shift distance is 1 to 10
By setting mm, most human bodies can be handled.

[0014] Next, the upper end of the femur having the connector of the upper end of the femur according to claim 1 and a fixed shaft inserted into the support hole and engaged in the rotation direction inside the support hole. It is a jig set.

Here, an engaging inner surface portion is formed on an inner peripheral surface of the support hole, and an engaging outer surface portion which engages with the engaging inner surface portion in a circumferential direction is formed on an outer peripheral surface of the fixed shaft. A plurality of concave curved surfaces curved in the circumferential direction are periodically formed in the circumferential direction on one of the engagement inner surface portion and the engagement outer surface portion, and the other in the circumferential direction is formed on the other. It is preferable that a plurality of convex curved surfaces curved periodically are formed in the circumferential direction, and the concave curved surface has a larger radius of curvature than the convex curved surface.

According to this means, a plurality of concave curved surfaces are formed on one of the engaging inner surface formed on the inner peripheral surface of the support hole and the engaging outer surface formed on the outer peripheral surface of the fixed shaft. On the other hand, a convex curved surface is formed, and since the concave curved surface has a larger radius of curvature than the convex curved surface, each concave curved surface and the convex curved surface are in a state where the engaging inner surface portion and the engaging outer surface portion are engaged. Since they almost come into line contact with each other at one point in the circumferential direction, even if the play between the inner diameter of the support hole and the outer diameter of the fixed shaft is reduced, bite hardly occurs. The connector and the fixed shaft can be engaged with high precision without impairing the performance.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of an embodiment of the present invention. FIG. 1 is a front view of the connector according to the present embodiment, FIG. 2 is a rear view of the connector, and FIG. 3 is a left side view of the connector.

The connector 10 of the present embodiment is integrally formed using a titanium alloy (Ti-6AL-4V) made of Ti (titanium), Al (aluminum), and V (vanadium). The connector 20 includes a plate-shaped fixing plate portion 21 extending in the vertical direction in the figure, and a support hole 22 a having an axis connected to the upper end of the fixing plate portion 21 and inclined with respect to the plate surface of the fixing plate portion 21. And a sleeve portion 22 having the same.

The fixed plate portion 21 has a smooth curved semicylindrical surface 21a shown in FIG. 1, and both edges in the width direction shown in FIG. 2 are formed substantially flat, and the portion excluding the both edges is a thigh. Cylindrical surface of bone femur 10 (upper surface 10a)
The back surface 2 which is depressed on an arc so that it exactly matches
1b. The fixing plate 21 is provided with a plurality of fixing holes 21c penetrating the front and back so as to be arranged along the direction of the axis 21X of the fixing plate 21 (vertical direction in the drawing). Fracture location, fracture plane orientation,
Since the length of the fixing plate 21 is appropriately changed depending on the size of the skeleton or the like, the number of the fixing holes 21c is
It is manufactured by setting appropriately according to the length of 1 and necessary fixing force.

The uppermost fixing hole 21c in the drawing of the fixing plate portion 21 has an inner curved surface that is symmetrical in the vertical and horizontal directions, while the remaining three fixing holes 21c have a lower inner surface portion in the drawing. It is formed on a substantially vertical vertical inner surface. This is a structure for pressing the bone portions on both sides of the fracture line together when a fracture line exists between the uppermost fixing hole 21c of the fixing plate portion 21 and the remaining three fixing holes 21c. That is, in these fixing holes 21c,
A bone screw having a head with an outer curved surface matching the uppermost fixing hole 21c is used, but the remaining three fixing holes 2c are used.
When a drill hole is formed in the bone along the vertical inner surface of 1c, and the bone screw is screwed into the drill hole, the outer curved surface of the head of the bone screw comes into contact with the vertical inner surface as the bone screw is screwed in. Since the bone screw is pushed upward in the figure, the bone screw and the screwed bone portion of the bone screw can be pressed upward in the figure by screwing in the bone screw.

The sleeve portion 22 is formed in a cylindrical shape that extends obliquely from the front surface side to the rear surface side and projects obliquely toward the rear surface side from the extension plane of the rear surface 21b of the fixed plate portion 21. The sleeve portion 22 is formed with a support hole 22a penetrating in the extension direction. Except for a portion near the opening edge of the front and back of the support hole 22a, a plurality of ribs 22b having an arc-shaped cross section extending in the direction of the axis 22X of the support hole 22a are formed on the inner peripheral surface of the support hole 22a. These plurality of ribs 22
b constitutes an engagement inner surface portion which engages with an outer peripheral surface of a head of a lag screw which is a fixed shaft described later.

The fixed plate portion 21 and the sleeve portion 22 have a mutually twisted positional relationship as described below. The axis 21X of the fixed plate portion 21 and the axis 22X of the support hole 22a of the sleeve portion 22 include a flat portion of the back surface 21b of the fixed plate portion 21 and extend on the extension plane 21P shown in FIG. As shown in FIG. 2, they are separated by a shift distance S.

As shown in FIG. 3, the axis 22X of the sleeve 22 has an angle Θ substantially corresponding to the neck angle θ of the femur between the sleeve 22 and the extension plane 21P.
An angle inclined in the left-right direction in the figure is also provided between the fixed plate portion 21 and the axis 21X. Note that, in this description, the axis 21X of the fixed plate portion 21 is
It is described as being within 1P.

The shape of the connector shown in FIGS. 1 to 3 will be described with reference to FIG. First, the axis 21 of the fixed plate 21
X, an extension plane 21P parallel to the fixed plate portion 21
Is assumed to be a virtual orthogonal plane 21Q orthogonal to.
The orthogonal plane 21Q is orthogonal to the extension plane 21P at the axis 21X. At this time, the sleeve 2
The point where the second axis 22X intersects the extension plane 21P is defined as an intersection R, and the closest point on the axis 21X on the extension plane 21P from the intersection R is defined as a center point O. Here, the distance between the center point O and the intersection R is the above-mentioned shift distance S.

A straight line passing through the intersection R,
Draw a parallel line 21X '(two-dot chain line in the figure) parallel to 1X,
The angle between the parallel line 21X ′ and the axis line 22X is defined as a neck-corresponding angle Θ. The neck corresponding angle 対 応 is an angle substantially corresponding to the above-described neck angle θ. A reference line 2 which is a straight line passing through the center point O, exists in the orthogonal plane 21Q, and has an angle between the axis 21X and the axis 21X is the neck corresponding angle Θ.
Subtract 2Y. This reference line 22Y is
This corresponds to the axis of the sleeve portion when there is no left and right twist. The angle between the axis line 22X and the reference line 22Y is a anteversion angle Φ substantially corresponding to the anteversion angle φ.

As described above, in the present embodiment, after being shifted left and right with respect to the fixed plate portion 21 by the shift distance S on the extension plane 21P, a cervical body corresponding angle Θ and a anteversion corresponding angle Φ are provided. A sleeve portion 22 having a support hole 22a projecting obliquely to the rear surface side in a direction opposite to the shift direction is provided. With such a structure, the connector of the present embodiment can be adapted to the upper end of the femur having the neck angle θ and the anteversion angle φ shown in FIG. 8.

In the present embodiment, the neck corresponding angle Θ is set according to the neck angle θ of the human body. That is, the neck angle θ
Is about 150 degrees for newborns and 126-128 for adults
The degree is about 120 degrees for the elderly, and tends to gradually decrease with aging. Therefore, the cervical body corresponding angle Θ generally needs to be formed within the range of 110 to 160 degrees, and in particular, considering the main age group (youth to elderly people) requiring the joint, Body correspondence angle １２０ 120-1
Most preferably, it is set within the range of 40 degrees.

The anteversion angle Φ is set according to the anteversion angle φ of the human body. The anteversion angle φ is often in the range of 15 to 57 degrees for newborn babies, about 31 degrees on average, and often in the range of 20 to 50 degrees for infants 1 to 3 years old.
The average of 2 years old is 30 degrees, the average of 4-5 years old is 28 degrees,
The average of 12-year-olds is 18 degrees, and the average of 15-17-year-olds is 14 degrees, which tends to decrease with growth. For adults, the range is often between 12 and 14.6 degrees, with an average of 13 to 1
It is about 4 degrees. Mostly, the anteversion is said to vary considerably from race to race, with Asian races having larger anteversion than Europeans. Therefore, the anteversion corresponding angle Φ
Can be used for most patients if it is set within the range of 10 to 60 degrees, and can generally be used for a normal human body within the range of 11 to 20 degrees. In particular, for adults, the angle may be set within the range of 12 to 14 degrees.

As a result of trial of the above-mentioned shift distance S by the operation of the femur, it has been found that when the shift distance S is about 3 mm, the adaptability and the correspondence are the highest. This shift distance S
Can be provided within a range of 1 to 10 mm, and in particular,
A thickness of 2 to 4 mm is preferable for obtaining compatibility with an average human body. It has been confirmed that if the shift distance S is not provided at all, it is difficult to fit the femur even when the above-described frontal angle Φ is set.

Next, other features of the present embodiment will be described. FIG. 4 shows a cross-sectional structure of a support hole 22 a formed inside the sleeve portion 22. In this embodiment, twelve ribs 22b protruding from the inner peripheral surface of the support hole 22a in an arc-shaped cross section are formed at equal angular intervals. The rib 22b is adapted to engage with the outer peripheral surface of the head of a lag screw 30 as a fixed shaft described below.

FIG. 5 shows the overall configuration of the lag screw 30 engaging with the rib 22b, with a part of the lengthwise direction omitted, and FIG. 6 shows the lag screw 30 viewed from the upper end. Is shown. The lag screw 30 is formed of a titanium alloy, and the screw shaft 3 extends vertically in the figure.
1 and a screw thread 3 formed at the lower end of the screw shaft 31
It comprises a screw portion 32 having 2 a and a head portion 33 formed at the upper end of the screw shaft 31. Inside the lag screw 30, a guide hole 30a penetrating vertically is formed. Twelve concave grooves 33a having an arcuate cross section are formed in the outer peripheral surface of the head 33 at equal angular intervals, and are formed downward from the upper end of the head and communicate with the guide holes 30. A pair of notches 33b are provided at opposing positions. The plurality of concave grooves 33a constitute an engaging outer surface portion that engages with the plurality of ribs 22b that are the engaging inner surface portions.

The notch 33b is used to engage a rotary operation tool such as a screwdriver for rotating the lag screw 30 when screwing the lag screw 30 into the bone or removing it from the bone. is there. The notch 33b is compatible with a screw driver having a minus-shaped tip, but is compatible with a rotary operating instrument having various tip shapes such as a cross, a hexagon, and a square. It can be configured in various shapes.

The lag screw 30 is screwed into the femur along the axis B of the head 14 shown in FIG. Usually, after inserting a guide pin having a cutting edge at the tip into the femur in advance, a hole having a predetermined diameter is formed around the guide pin by a hollow tool called a step drill or a step reamer. Tapping may be applied to the inner surface of the hole. Then, the lag screw 30 is screwed into the hole along the guide pin. When the screw portion 32 at the tip of the lag screw 30 completely reaches the head of the femur, the head portion 33 of the lag screw 30 is introduced into the support hole 22a of the connector 20, and the sleeve portion 22 is inserted into the drill hole. It is inserted, and it is confirmed whether the fixing plate portion 21 is exactly in contact with the upper side surface 10a of the femur 10.

When this is confirmed, the fixing plate 21
The position of the fixing hole 21c on the femur 10 is grasped, the joint is once removed, and a screw hole is drilled in the upper side surface 10a of the femur using a drill or the like. After that, the joint is attached again, and the fixing screw is passed through the fixing hole of the fixing plate portion 21 so that the femur 10
The fixation plate portion 21 is completely fixed on the femur.

In the present embodiment, a concave groove 33a is formed on the outer peripheral surface of the head 33 of the lag screw 30. The concave groove 33a is formed in the support hole 22 of the sleeve portion 22 of the connector 20.
a in a rotational direction with the rib 22b formed in the inner portion a. For this reason, the rotation of the lag screw 30 can be prevented by attaching the sleeve portion 22 of the connector 20 to the lag screw 30 screwed into the bone.

At this time, the radius of curvature of the surface of the groove 33a in the circumferential direction is set slightly larger than the radius of curvature of the surface of the rib 22b in the circumferential direction.
The rib 22b and the rib 22b come into linear contact with each other only in the central portion, so that they can be engaged in the rotational direction without meshing with each other. For example, the radius of curvature of the surface of the rib 22b is 1.4 mm, and the radius of curvature of the inner surface of the groove 33a is 1.5.
mm.

Conventionally, the outer peripheral surface of the head 33 of the lag screw 30 and the inner peripheral surface of the support hole 22a of the sleeve portion 22 are engaged by a square or hexagonal bolt or nut-shaped engagement surface. However, in such an engagement surface, the head 33
If the play between the support hole 22a and the support hole 22a is small, they may mesh with each other, causing a problem such as temporary difficulty in removal and position correction, resulting in deterioration of workability. Conversely, if there is a large amount of play between the two, there is a problem that rattling occurs and secure fixing cannot be performed, and the attachment of the connector 20 becomes meaningless.

In the present embodiment, the engaging surface is constituted by a convex curved surface and a concave curved surface having different curvatures, and both are contacted only in a single linear shape extending in the axial direction. Even if this happens, there is no danger of engagement, and the outer diameter of the head 33 and the inner diameter of the support hole 22a can be engaged with high precision. Further, since the number of ribs 22b and concave grooves 33a to be formed can be as large as 12, it is possible to avoid a problem due to the angular orientation of the lag screw 30 and the connector 20 not matching.

In the above embodiment, the fixing plate portion and the sleeve portion are integrally formed. However, in the present invention, it is only necessary that the connector has the fixing plate portion and the sleeve portion. As shown in FIG. 7, a member (plate body) corresponding to the main part of the fixed plate portion
Even if the member (support member) having a portion corresponding to the sleeve portion is a separate member, the same can be applied.

[0040]

According to the present invention, a support hole having an intersection with an extension plane at a position shifted with respect to the axis of the fixed plate portion and extending at a second angle to the opposite side to the shift direction. Since it is possible to cope with the shift amount and the anteversion angle of the femoral head when the fixing shaft is inserted and fixed in the support hole, it is possible to improve the compatibility with the femur. Thus, the operation of fixing the fracture can be facilitated, and the fracture can be reliably and accurately fixed.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a femoral upper end connector according to the present invention.

FIG. 2 is a rear view of the embodiment.

FIG. 3 is a left side view of the embodiment.

FIG. 4 is a cross-sectional view of a sleeve portion in the embodiment.

FIG. 5 is a partially omitted front view of the lag screw corresponding to the connector of the embodiment.

FIG. 6 is a plan view of the lag screw.

FIG. 7 is a side view showing a structure of a connector different from the above embodiment.

FIG. 8 is a perspective view showing the shape of the upper end of the femur.

FIG. 9 is a conceptual explanatory diagram for explaining the shape of the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 femoral body 13 neck 14 bone head 20 connector 21 fixing plate 21 a front surface 21 b back surface 21 c fixing hole 21 X axis 21 P extension plane 21 Q orthogonal plane 22 sleeve part 22 a support hole 22 b rib 22 X axis 22 Y reference line 30 lag screw 31 32 Screw part 33 Head 33a Groove

Claims (5)

[Claims] Claims: 1. A back surface contacting an upper side surface of a femur,
A fixed plate portion configured to be fixed to the upper side surface, and a projection onto an orthogonal plane including an axis of the fixed plate portion and orthogonal to an extension plane of the back surface intersects the extension plane at a first angle. A support shaft provided with an axis to be provided, a sleeve portion configured to protrude from the extension plane, and a fixed shaft configured to be embedded in bone is used in a state where the fixed shaft is inserted through the support hole. A joint of the upper end of the femur, wherein the axis of the support hole is an intersection on the extension plane shifted by a predetermined shift distance to one of both sides of the axis of the fixing plate. A connector for an upper end portion of a femur, which is configured to pass through and extend at a second angle in a direction opposite to a shift direction toward a projecting direction of the sleeve portion at a second angle. 2. The connector according to claim 1, wherein the second angle is an angle within a range of 10 to 60 degrees, which substantially corresponds to the anteversion angle of the femur. . 3. The joint device for an upper end of a femur according to claim 1, wherein the shift distance is 1 to 10 mm. 4. The joint of the upper end of the femur having the connector of the upper end of the femur according to claim 1 and a fixed shaft inserted into the support hole and engaged in the rotation direction inside the support hole. Tool set. 5. The engagement according to claim 4, wherein an engagement inner surface portion is formed on an inner peripheral surface of the support hole, and an outer peripheral surface of the fixed shaft is engaged with the engaging inner surface portion in a circumferential direction. An engagement outer surface portion is formed, and one of the engagement inner surface portion and the engagement outer surface portion includes:
A plurality of concave curved surfaces curved in the circumferential direction are formed periodically in the circular direction, and a plurality of convex curved surfaces curved in the circular direction are formed periodically in the circular direction on the other side; A joint set for an upper end of a femur, wherein the radius of curvature is larger than that of the convex curved surface.