Adjustment device

Abstract

To provide an adjustment device which can facilitate fitting of a control component to a rotary component.SOLUTION: An adjustment device 1 fixes a main lag screw in an intramedullary nail for engaging a bone chip which is separated from a femur. The adjustment device 1 has a control component 3 and a rotary component 5. The rotary component 5 has a support part 35, and a connection part 37 on the support part 35. The control component 3 has a tip end part 11, a first side part 15, a first protrusion part 19, a first gripping part 23, a second side part 17, a second protrusion part 21, and a second gripping part 25. The first gripping part 23 and the second gripping part 25 hold the connection part 37. The first side part 15 and the first protrusion part 19 expand independently from the second side part 17 and the second protrusion part 21, when outward force is applied to the first gripping part 23. A sub lag screw exists between the first side part 15, the first protrusion part 19, the second side part 17, and the second protrusion part 21. The tip end part 11 presses the main lag screw to fix the same.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an adjustment device for fixing a main lag screw in an intramedullary nail.

Background Art

[0002] As disclosed in Patent Document 1, the applicant has proposed an intramedullary nail using a main lag screw and an auxiliary lag screw for engaging bone fragments separated from the femur.

[0003] Patent Document 2 discloses an example of an adjuster used in an intramedullary nail.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] FIG. 6 shows an example of the intramedullary nail 103 of Patent Document 1. In FIG. 6, the intramedullary nail 103 uses a main lag screw 105 and an auxiliary lag screw 107 for engaging bone fragments separated from the femur 101. An adjuster for fixing the main lag screw 105 in the intramedullary nail 103 is known to include a rotating portion 111 that rotates and a sliding portion 109 that slides without rotating.

[0006] However, in Patent Document 1, since the rotating part and the sliding part were independent components, there were cases where, for example, even though the rotating part was near the entrance, the sliding part would go deep inside. Also, a protruding part was provided on the sliding part to prevent rotation, but this protruding part was divided at the part sandwiching the sub-lug screw 107 and fit into the same recess. Therefore, there was a possibility that the sliding part would rotate. In particular, the main lug screw 105 must always be used, but the sub-lug screw 107 may not be used. The possibility of rotation increases when the sub-lug screw 107 is not used.

[0007] Also, Patent Document 2 describes that the sliding part is rotatably connected to the rotating part by inserting the sliding part laterally into the rotating part. However, it only connects the rotating part and the sliding part and does not perform the function of fixing the sub-lug screw by the sliding part as in Patent Document 1. Furthermore, when the adjuster connected in this way is inserted into the intramedullary nail, if the hand shakes with the sliding part inserted, it is easily detached, and the sliding part may enter the intramedullary nail in a state separated from the rotating part. And once it is detached, fine work is required to reconnect it.

[0008] Therefore, an object of the present invention is to provide an adjustment device that can easily attach a control part to a rotating part.

Means for Solving the Problems

[0009] A first aspect of the present invention is an adjustment device for fixing a main lag screw in an intramedullary nail using a main lag screw and an auxiliary lag screw for engaging a bone fragment separated from the femur. The adjustment device includes a control component and a rotating component. The rotating component includes a support portion and a connecting portion on the support portion. The control component includes a tip portion, a first side portion, a first protruding portion, a first gripping portion, a second side portion, a second protruding portion, and a second gripping portion. The first side portion and the second side portion are located at different positions at the tip portion. The first protruding portion and the second protruding portion are respectively located on the first side portion and the second side portion. The first gripping portion and the second gripping portion are respectively formed at upper portions inside the first protruding portion and the second protruding portion. The first gripping portion and the second gripping portion sandwich the connecting portion. The auxiliary lag screw is located between the first side portion and the first protruding portion and the second side portion and the second protruding portion. The tip portion presses and fixes the main lag screw.

[0010] A second aspect of the present invention is the adjustment device of the first aspect. In the first side portion, the first protruding portion, and the first gripping portion, when an outward force is applied to the first gripping portion, the first side portion and the first protruding portion expand independently of the second side portion and the second protruding portion. When an inward force is applied to the first protruding portion, an inward force is applied to the first gripping portion.

[0011] A third aspect of the present invention is the adjustment device of the first or second aspect. On the side surface of the adjustment device hole into which the adjustment device is inserted in the intramedullary nail, a first recess and a second recess, which are different recesses, are formed. The first protruding portion and the second protruding portion respectively fit into the first recess and the second recess.

Advantages of the Invention

[0012] According to the invention of the present application, by utilizing the space through which the auxiliary lag screw passes in the control component to separate and independently form the first side portion, the first protruding portion, and the first gripping portion from the second side portion, the second protruding portion, and the second gripping portion, a sufficient length for the first side portion and the second side portion to deform is ensured, and the user can easily attach the control component to the rotating component. Furthermore, by utilizing the fixing of the main lag screw by the tip portion, the first side portion and the first protruding portion, and the second side portion and the second protruding portion can be curved inward to narrow the gap and also fix the auxiliary lag screw.

[0013] Furthermore, as in the second aspect of the invention of the present application, taking the tip portion as a fulcrum, for example, when the control component is pressed against the support portion to attach the control component to the rotating component and an outward force is applied to the first gripping portion, the end deforms and spreads, enabling easy attachment. When an inward force is applied to the first protruding portion or the like in the intramedullary nail, an inward force is applied to the first gripping portion, firmly gripping and making it difficult for the control component to come off from the rotating component.

[0014] Furthermore, if the protruding portions are fitted into the same recess, an unintended state such as torsion may occur due to an external force. As in the third aspect of the invention of the present application, by ensuring that the first protruding portion and the second protruding portion fit into different recesses and do not fit into the same recess, such an unintended state can be avoided. Even when the auxiliary lag screw is not used, rotation can be similarly prevented.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to these embodiments.

[0017] FIG. 1 is a view showing an example of the configuration of a control component 3 that constitutes an adjustment device according to an embodiment of the present invention. The control component 3 controls the degree of fixation with respect to a main lag screw inserted into an intramedullary component inserted into the medulla.

[0018] The control component 3 includes a tip portion 11, a hole 13, a first side portion 15, a second side portion 17, a first protruding portion 19, a second protruding portion 21, a first gripping portion 23, and a second gripping portion 25.

[0019] The tip portion 11 is located at the tip of the control component 3 that is first inserted into the intramedullary component. The tip portion 11 has a hole 13.

[0020] The control component 3 has a first side portion 15 on one side and a second side portion 17 on the other side above the tip portion 11. The outer surfaces of the first side portion 15 and the second side portion 17 are located inside the tip portion 11.

[0021] The control component 3 has a first protruding portion 19 and a second protruding portion 21 on the first side portion 15 and the second side portion 17, respectively. A part of the outer surface of the first protruding portion 19 and the second protruding portion 21 protrudes outside the tip portion 11.

[0022] The control component 3 has a first gripping portion 23 and a second gripping portion 25 inside the first protruding portion 19 and the second protruding portion 21, respectively. The inside of the first protruding portion 19 and the second protruding portion 21 is narrowed by the first gripping portion 23 and the second gripping portion 25 and has a shape that widens below.

[0023] Figures 1(b) and (d) are respectively the front view and the plan view of the control component 3. As shown in Figure 1(b), the first side portion 15, the first protruding portion 19, and the first gripping portion 23 are separated from the second side portion 17, the second protruding portion 21, and the second gripping portion 25, and are connected only by the tip portion 11. Figure 1(c) is a cross-sectional view of the control component 3 at the center.

[0024] Figure 2 is a diagram showing an example of the configuration of the rotating component 5 (end cap) that constitutes the adjustment device according to the embodiment of the present invention. The rotating component 5 includes a male groove portion 31, a rotation operation portion 33, a support portion 35, and a connecting portion 37. Figure 2(a) is a perspective view of the rotating component 5, Figure 2(b) is a cross-sectional view of the center of the rotating component 5, and Figures 2(c) and (d) are respectively the plan view and the front view of the rotating component 5.

[0025] The male groove portion 31 has a groove of male threads formed on its outer surface.

[0026] The rotation operation portion 33 has a hexagonal columnar hole formed from above. The user can rotate the rotating component 5 by inserting and rotating a hexagonal rod-shaped member.

[0027] The support portion 35 has its outer surface existing inside the male groove portion 31. The connecting portion 37 connects the support portion 35 and the male groove portion 31, and its outer surface exists inside the support portion 35.

[0028] Figure 3 is a diagram showing the configuration of the adjustment device 1 according to the embodiment of the present invention. The adjustment device 1 is in a state where the control component 3 in Figure 1 and the rotating component 5 in Figure 2 are combined. In the intramedullary nail 103 in Figure 6, by using the adjustment device 1 in which the control component 3 and the rotating component 5 are combined instead of the adjuster having the slide portion 109 and the rotating portion 111, an intramedullary nail can be realized.

[0029] Figure 3(a) is a perspective view of the adjustment device 1, Figures 3(b) and (c) are respectively the plan view and the front view of the adjustment device 1, and Figure 3(d) is a cross-sectional view of the center of the adjustment device 1.

[0030] Referring to Fig. 3(d), in the control component 3, a first side portion 15 and a first protruding portion 19 exist upward from one side of the tip portion 11, and a first gripping portion 23 is formed inside the upper hollow portion. A second side portion 17 and a second protruding portion 21 exist upward from the other side of the tip portion 11, and a second gripping portion 25 is formed inside the upper hollow portion. Thus, the first side portion 15 and the second side portion 17 exist above different positions at the tip portion 11.

[0031] The first gripping portion 23 and the second gripping portion 25 hold the connecting portion 37 of the rotating component 5 from both sides. The first gripping portion 23 and the second gripping portion 25 can be held without coming off downward by the support portion 35. Since the support portion 35 is columnar (with a circular cross-section), even if the control component 3 moves up and down without rotating, the rotating component 5 can be in a state where it can rotate.

[0032] The first protruding portion 19 and the second protruding portion 21 are shaped to protrude outward from the other outer surface of the adjusting device 1 (especially the outer surface of the male groove portion 31). Therefore, by moving the control component 3 up and down without rotating it by means of the grooves formed with the first protruding portion 19 and the second protruding portion 21 formed vertically, the control component 3 can be moved up and down without rotating. The first protruding portion 19 and the second protruding portion 21 are shaped such that the center protrudes and the ends do not protrude. Therefore, the force applied to the first protruding portion 19 and the second protruding portion 21 from the outside acts as a force that holds the first gripping portion 23 and the second gripping portion 25 so as to wrap them inward with the tip portion side as a fulcrum, and the state of holding the connecting portion 37 can be maintained.

[0033] The first side portion 15, the first protruding portion 19, and the first gripping portion 23 are separated from the second side portion 17, the second protruding portion 21, and the second gripping portion 25. Therefore, when attaching the first gripping portion 23 and the second gripping portion 25 to the connecting portion 37 of the rotating component 5, the user, for example, presses the first gripping portion 23 and the second gripping portion 25 against the supporting portion 35. Then, a force is applied to the first gripping portion 23 and the second gripping portion 25 from the supporting portion 35 in a direction of spreading outward. Then, due to the extension (elongation and existence) of the first side portion 15 and the second side portion 17, the upper parts of the first side portion 15 and the second side portion 17 are deformed to spread, and the distance between the first gripping portion 23 and the second gripping portion 25 can be made wider than the supporting portion 35. And when exceeding the supporting portion 35, the force in the outward spreading direction disappears and the first side portion 15 and the second side portion 17 return to their original states, and the first gripping portion 23 and the second gripping portion 25 clamp the connecting portion 37. In this way, the first side portion 15, the first protruding portion 19, and the first gripping portion 23 are separated from the second side portion 17, the second protruding portion 21, and the second gripping portion 25 by using the space for the sub-lag screw to pass through in the control component 3. Therefore, when an outward force is applied to the first gripping portion 23 and the second gripping portion 25, the first side portion 15 and the first protruding portion 19 spread independently of the second side portion 17 and the second protruding portion 21, and a sufficient length that allows the upper parts of the first side portion 15 and the second side portion 17 to be deformed to spread is ensured. Therefore, the user can easily attach the control component 3 to the rotating component 5.

[0034] FIG. 4 is a view showing a portion where the adjustment device 1 is inserted among the intramedullary components inserted into the medulla. The intramedullary component includes a main through-hole 53 through which the main lag screw is inserted and a sub-through-hole 51 through which the sub-lag screw is inserted. The adjustment device hole 41 is formed in a columnar shape longitudinally downward from the upper surface of the intramedullary component to the inside, and is formed from the sub-through-hole 51 to the main through-hole 53. A first recess 43 extending vertically is formed on the side surface of the adjustment device hole into which the adjustment device 1 is inserted, and a second recess 45 extending vertically is formed at a position facing the first recess 43.

[0035] The intramedullary nail is an instrument used when engaging bone fragments separated from the femur due to a fracture with the femur. The intramedullary component is one of the members constituting the intramedullary nail and is generally rod-shaped as a whole. The intramedullary component includes a proximal portion close to the intramedullary entrance where it is introduced and a distal portion that is longer than the proximal portion and is introduced deeper into the medulla. The part in Figure 4 is included in the proximal portion. The proximal portion is formed thicker because the main through-hole 53 and the sub-through-hole 51 are provided. The distal portion is formed thinner according to its shape for insertion into the lumen (bone marrow cavity) of the femur. The main through-hole 53 and the sub-through-hole 51 are provided in an oblique direction in the proximal portion of the intramedullary component. The main lag screw is inserted through the main through-hole 53, and the indicated sub-lag screw is inserted through the sub-through-hole 51.

[0036] The sub-lag screw is provided with an engaging portion such as a threaded portion at the tip for engaging with the bone fragment separated from the femur. The engaging portion is inserted into the femur with the tip facing forward, and then directly inserted into the sub-through-hole 51 of the intramedullary component and further arranged to penetrate into the separated bone fragment.

[0037] Also, the diameter of the hole of the sub-through-hole 51 is different on the side where the sub-lag screw is inserted and the side where it exits. Therefore, the end of the sub-lag screw without the engaging portion can move up and down on the axis in the longitudinal direction of the intramedullary component with the smaller hole as the fulcrum while being inserted into the sub-through-hole 51. In this way, if there is a movable range for the sub-lag screw inserted into the sub-through-hole 51, the sub-lag screw can be arranged at various angles with respect to the longitudinal axis of the intramedullary component. Then, with the sub-lag screw penetrated into the femur and the separated bone fragment, the angle between the femur and the separated bone fragment can be aligned to an appropriate position, or differences between patients can be addressed.

[0038] The main lag screw has an engaging portion such as a threaded portion at its tip for engaging with a bone fragment separated from the femur, and a plurality of grooves extending in the axial direction are formed on the proximal end side thereof. This main lag screw is inserted into the femur with the engaging portion facing the tip, inserted as it is into the main through-hole 53 of the intramedullary component, and further arranged to penetrate into the separated bone fragment. Then, by engaging the engaging portion of one end of the main lag screw with the separated bone fragment, the main lag screw is fixed and held to the bone fragment, and by fixing the main lag screw to the main through-hole 53 of the intramedullary component inserted into the femur, the separated bone fragment is fixed to the femur. Further, the first side portion 15 and the first protruding portion 19 and the second side portion 17 and the second protruding portion 21 are curved inward and narrowed with respect to each other, so that the auxiliary lag screw is also fixed. The auxiliary lag screw and the main lag screw form two fixing axes between the separated bone fragment and the intramedullary component, thereby preventing the separated bone fragment from rotating.

[0039] Inside the adjustment device hole 41, a groove of a female screw is formed in part from above corresponding to the groove of the male groove portion 31. When the user inserts the rotating part 5 into the adjustment device hole 41 and rotates it using the rotation operation part 33, the rotating part 5 can be moved up and down by the groove of the inner female screw and the groove of the male groove portion 31. The control component 3 moves up and down together in accordance with the up and down movement of the rotating part 5.

[0040] The first recess 43 and the second recess 45 are grooves formed vertically corresponding to the shapes of the first protruding portion 19 and the second protruding portion 21, respectively. The control component 3 moves up and down according to the first recess 43 and the second recess 45 formed vertically without rotating when the first protruding portion 19 and the second protruding portion 21 fit into the first recess 43 and the second recess 45. If the first protruding portion 19 and the second protruding portion 21 fit into the same recess, an unintended state such as torsion may occur due to an external force. By ensuring that the first protruding portion 19 and the second protruding portion 21 fit into different first recess 43 and second recess 45 and do not fit into the same recess, such an unintended state can be avoided. Even when the auxiliary lag screw is not used, rotation can be prevented in the same manner.

[0041] Figure 5 is a diagram showing a state in which the adjustment device 1 of FIG. 3 is inserted into the intramedullary component of FIG. 4. FIG. 5(a) shows a perspective view. FIG. 5(b) is a diagram showing the internal state when viewed through from the front. FIG. 5(c) is a diagram showing the internal state with the intramedullary component cut at the center. FIG. 5(d) shows a plan view. FIGS. 5(e) and (f) show cross-sectional views at the center. FIG. 5(e) is by a cross-section passing through the center of each of the first side portion 15 and the second side portion 17. FIG. 5(f) is by a cross-section passing so as to separate the first side portion 15 and the second side portion 17.

[0042] The tip portion 11 of the control component 3 presses down and fixes the main lag screw inserted into the main through-hole 53 when the rotating component 5 moves downward, and releases the state of pressing the main lag screw inserted into the main through-hole 53 when the rotating component 5 moves upward, so that it can be inserted and removed.

[0043] The sub-lag screw inserted into the sub-through-hole 51 exists in the space between the first side portion 15, the first protruding portion 19 and the first gripping portion 23, and the second side portion 17, the second protruding portion 21 and the second gripping portion 25. Therefore, the sub-lag screw can adjust the angle and the like. Further, even if the control component 3 moves up and down, it does not affect the state of the sub-lag screw.

Explanation of Reference Numerals

[0044] 1 Adjustment device 3 Control component 5 Rotating component 11 Tip portion 13 Hole 15 First side portion 17 Second side portion 19 First protruding portion 21 Second protruding portion 23 First gripping portion 25 Second gripping portion 31 Male groove portion 33 Rotating operation portion 35 Support portion 37 Connecting portion 41 Hole for adjustment device 43 First recess 45 Second recess 51 Auxiliary through-hole 53 Main through-hole 101 Femur 103 Intramedullary nail 105 Main lag screw 107 Auxiliary lag screw 109 Slide portion 111 Rotating portion

Claims

1. An adjustment device for fixing a main lag screw in an intramedullary nail using a main lag screw and an auxiliary lag screw that engage bone fragments separated from the femur, The adjustment device includes a control component and a rotating component, The rotating component includes a support portion and a connecting portion on the support portion, The control component includes a tip portion, a first side portion, a first protruding portion, a first gripping portion, a second side portion, a second protruding portion, and a second gripping portion, The first side portion and the second side portion are located at different positions at the tip portion, The first protruding portion and the second protruding portion are respectively located on the first side portion and the second side portion, The first gripping portion and the second gripping portion are respectively formed at the upper inner sides of the first protruding portion and the second protruding portion, The first gripping portion and the second gripping portion sandwich the connecting portion, The auxiliary lag screw is located between the first side portion and the first protruding portion and the second side portion and the second protruding portion, The tip portion presses and fixes the main lag screw, an adjustment device.

2. In the first side portion, the first protruding portion, and the first gripping portion, When an outward force is applied to the first gripping portion, the first side portion and the first protruding portion expand independently of the second side portion and the second protruding portion, When an inward force is applied to the first protruding portion, an inward force is applied to the first gripping portion, the adjustment device according to Claim 1.

3. On the side surface of the hole for the adjustment device into which the adjustment device is inserted in the intramedullary nail, a first recess and a second recess, which are different recesses, are formed, The first protruding portion and the second protruding portion respectively fit into the first recess and the second recess, the adjustment device according to Claim 1.

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