JP2016195746A - Intramedullary fixation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intramedullary fixation device that can enhance a convolution prevention effect and a reduction maintenance effect.SOLUTION: An intramedullary fixation device 100 of the present invention comprises: an intramedullary nail 110 having a shaft hole 113 extending in the direction of an axis line from a base end, a first transverse hole 114, and a pair of second transverse holes 115 formed at the side of the base end from the first transverse hole and including the axis line on both sides of the axis line and in respectively biased positions; a first axial member 10 inserted in the first transverse hole; a second axial member 20 inserted in at least one side of the pair of second transverse holes; a first holding mechanism 121A, 125 stored in the shaft hole and engaged with the first axial member, and configured in a holding manner; and a second holding mechanism 121B, 125 stored in the shaft hole and engaged with the pair of second axial members, and configured in a holding manner.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intramedullary fixation device, and more particularly to a structure of a device suitable for treating a fracture of a proximal femur.

  In general, as an intramedullary fixation device, an intramedullary nail inserted into the medulla of a long bone such as a femur, and a bone screw or nail that is fixed in a state crossing the intramedullary nail within the bone, What has 1st shaft-shaped members, such as a pin, is known. The first shaft-like member is fixed in a state of being inserted through a transverse hole provided in the intramedullary nail, and holds the fracture portion on the main body of the long bone. Often used to hold a bone head. However, at the fracture site of the proximal femur, if only one first shaft-like member is screwed inside the bone head, the bone head rotates around the bone screw during and after the operation. In this case, another transverse hole is formed on the proximal side of the intramedullary nail, and an additional bone screw is used to prevent rotation of the bone head. In some cases, a second shaft member such as a pin or a pin is inserted.

  As an intramedullary fixation device using an additional bone screw or pin in order to prevent the rotation of the bone head as described above, for example, those described in Patent Documents 1 to 3 below are known. In Patent Document 1, the locking mechanism 22 built in the intramedullary nail 102 passes the second screw 25 to lock the first screw 10, and the lag screw 62 locks the second screw. It is described that the locking mechanism 22 passes between the second screw and the third screw and engages with the first screw (see FIG. 5C). In Patent Document 2, a slot 154 for allowing the rotation restricting member 114 to pass therethrough is provided in a lug screw lock 150 for fixing the lug screw 112, and an end cap 170 is attached to form a lower bar shape of the end cap 170. An intramedullary nail is disclosed in which the portion 174 passes through the longitudinal passage 156 of the lug screw lock 150 and is engaged with the rotation restricting member 114. Further, in Patent Document 3, the first engagement member 121A is engageable with the bone screw 10 inserted through the first transverse hole 114, and the second engagement member 121B is engaged with the second transverse hole 115. An intramedullary fixation device is disclosed that is engageable with a bone screw 20 inserted through the bone.

International Publication No. 03/061495 International Publication No. 2010/117777 JP 2014-066463 A

  As described above, in the devices described in Patent Documents 1 to 3, the bone screw (first shaft-like member) corresponding to the lag screw and the bone screw or pin (second shaft) corresponding to the rotation restricting member. And the like) can be held by the engaging mechanism housed inside the intramedullary nail. Thereby, when receiving a torsional force due to the screwing operation of the first shaft-like member at the time of surgery or when receiving a load due to a load after the operation, the second shaft-like member is effective in preventing the rotation of the fracture site. The reduction reduction effect is aimed at. However, in recent years, there has been a problem that due to the increase in the number of elderly patients and early rehabilitation immediately after the operation, there are many problems due to insufficient rotation prevention effect and reduction maintenance effect.

  That is, in the example of a fracture of the proximal femur indicated by a two-dot chain line in FIG. 1, the intramedullary nail 110 is inserted from the proximal end B into the medullary cavity of the diaphysis A of the femur, The first shaft-like member 10 inserted through the first transverse hole 114 of the nail 110 passes through an inner position near the lower cortical portion of the neck D and reaches the cortical portion on the apex side of the bone head C. Screwed into. Further, when a single second transverse hole 115 ′ (shown by a dotted line in FIG. 1) is provided along the axis 111x of the intramedullary nail 110, the second transverse hole 115 ′ is inserted. The second shaft-shaped member 20 ′ (indicated by a dotted line in FIG. 1) extends through the substantially vertical center of the neck D toward the bone head C. At this time, since the intramedullary nail 110 is disposed in the medullary cavity of the diaphysis A of the femur, the second shaft-like member 20 ′ is arranged in the up-down direction UD and the front-back direction inside the bone head C and neck D. Any of the directions FB is inserted in the vicinity of the central portion. For this reason, since the second shaft-like member 20 'is disposed at a position away from the hard cortical portions on the surfaces of the bone head C and neck D, particularly in the case of elderly patients with advanced osteoporosis, The rotation prevention effect and reduction maintenance effect by the second shaft-like member 20 ′ are hardly obtained, and the bone head C rotates during the operation and after the operation, or the bone fragment moves from the position at the time of the reduction at the fracture site. Therefore, there is a high risk of causing serious damage such as causing a cutout in which the tip of the first shaft-shaped member 10 protrudes from the surface of the bone head C.

  Further, when the first shaft-like member 10 is screwed into a position deviated from the center in the front-rear direction FB of the bone head C or neck D to the front-rear direction FB, the load received during rehabilitation after surgery, etc. Due to the load, a rotating force is generated in a direction in which the portion opposite to the side on which the first shaft-like member 10 is displaced is generated in the bone head C, and thus a holding force that can withstand this rotating force is also required. However, in this case, not only the rotation of the bone head C cannot be avoided, but also most of the load load is applied directly to the second shaft-shaped member 20 ′ centering on the first shaft-shaped member 10. There is also a possibility that the second shaft-like member 20 'is broken.

  Therefore, the present invention solves the above-mentioned problems, and its object is to realize an intramedullary fixation device that can enhance the effect of preventing rotation and the effect of maintaining reduction. More preferably, it is an object of the present invention to provide an intramedullary fixation device that exhibits a high fracture holding effect while suppressing the complexity of work during surgery and the increase in product cost.

  In view of such circumstances, the intramedullary fixation device of the present invention includes an axial hole extending in the axial direction from the base end, a first transverse hole that opens into the axial hole and crosses and penetrates the axial line, and A second transverse hole formed closer to the base end than the first transverse hole, opening to the axial hole and passing through and passing through the axial line, A pair of the second transverse holes each having an axis at a position biased on both sides; an intramedullary nail inserted into the bone marrow; and the bone in a state of being inserted through the first transverse hole The first shaft-shaped member to be engaged, the second shaft-shaped member to be engaged with the bone while being inserted through at least one of the pair of second transverse holes, and the shaft hole are accommodated in the shaft hole. The first shaft-like member is engaged with the first shaft-like member inserted into the first transverse hole from the inside of the shaft hole, and the first shaft-like member is retained. A first holding mechanism configured to be engageable with the pair of second shaft-shaped members that are housed in the shaft hole and are respectively inserted into the pair of second transverse holes from the shaft hole. And a second holding mechanism configured to hold the pair of second shaft-like members.

  In the present invention, the second holding mechanism is arranged to be movable in the axial direction inside the shaft hole, and is configured to be able to engage with the pair of second shaft-shaped members at the same time. It is preferable that an engagement member and a positioning member for positioning the second engagement member are included.

  In the present invention, the second engagement member has a pair of contact surfaces that contact with the pair of second shaft-shaped members respectively inserted through the pair of second transverse holes. It is preferable to be provided on both sides of the axis at one end in the direction of.

  In this case, it is desirable that the second engaging member has a tip engaging portion formed along the axis of the second transverse hole. Then, the pair of contact surfaces provided at the tip engaging portion are arranged on the axis of the second shaft-shaped member with respect to the second shaft-shaped member inserted through the second transverse hole. It is preferable that it has the surface shape which comprises the contact area of the extended shape along.

  Further, the pair of contact surfaces are in contact with the second shaft member inserted through the second transverse hole so as to be in close contact with the outer peripheral surface of the second shaft member. It is desirable to have a surface shape that constitutes the contact area. For example, it is desirable that the tip engaging portion be formed in a concave curved surface that can be in close contact with the convex curved outer peripheral surface of the second shaft-like member inserted through the second transverse hole. Typically, the contact surface constitutes a part of a concave cylindrical surface corresponding to the convex cylindrical surface if the outer peripheral surface of the second shaft-shaped member is configured as a convex cylindrical surface. It may be a shape.

  In the present invention, it is preferable that the second engagement member has an elastic deformation structure that is configured to extend and contract a distance between a portion positioned by the positioning member and the pair of contact surfaces. This elastic deformation structure exerts an elastic restoring force from the contact surface to the second shaft-shaped member when the distance between the positioned portion and the pair of contact surfaces is reduced, The second shaft member is held by the frictional force resulting from this elastic restoring force.

  In the present invention, the elastic deformation structure is held by the second shaft-shaped member inserted through the second transverse hole according to a position along a direction of the axis of the portion positioned by the positioning member. It is preferable to increase or decrease the force. By positioning the portion of the second engaging member, the second shaft-like member does not move relative to the intramedullary nail regardless of the fracture portion, but the intramedullary portion moves with the movement of the fracture portion. A relatively small holding force that can move with respect to the nail can be provided, and the second shaft-like member not only does not move with respect to the intramedullary nail independently of the fracture portion. A relatively large holding force that does not move relative to the intramedullary nail even when the fracture portion moves can be applied.

  In the present invention, it is preferable that the elastic deformation structure gives an equal holding force to the pair of second shaft-shaped members inserted through the pair of second transverse holes, respectively. In the elastic deformation structure, an elastic deformation characteristic in a direction in which one abutment surface abuts on a corresponding second shaft-like member (in many cases, an axial direction) and the other abutment surface correspond to Since the elastic deformation characteristics in the direction of contact with the two shaft-shaped members (in many cases, the axial direction) are configured uniformly, the above-described holding force is evenly applied to the pair of second shaft-shaped members. Can be given. For example, in the case where the elastic deformation structure is configured by a slit extending in a spiral shape, which will be described later, the formation angle range from the start point to the end point of the slit is an axis about a symmetry axis passing through the middle of a pair of contact surfaces. Constructed symmetrically.

  In the elastic deformation structure, the second shaft-shaped member is inserted into only one of the pair of second transverse holes, and the other second transverse hole. It is desirable that the second shaft-shaped member inserted into any one of the second transverse holes can be held even when the second shaft-shaped member is not inserted through. In the elastic deformation structure, the amount of elastic deformation in a direction in which one abutting surface abuts on the corresponding second shaft-shaped member and the other abutting surface against the corresponding second shaft-shaped member. By having an elastic deformation characteristic that allows the amount of elastic deformation in the direction of contact to be different, even if one second shaft-shaped member is not present, the difference in the amount of elastic deformation is allowed. A holding force can be applied to the other second shaft member. Further, when the second engagement member is positioned so that the pair of contact surfaces contact the corresponding pair of second shaft members, respectively, the positional relationship between the pair of contact surfaces and the second shaft member Even if there is a slight difference, since the difference in the amount of elastic deformation is absorbed by the elastic deformation characteristic, a substantially uniform holding force can be applied to the pair of second shaft members.

  In the present invention, the elastic deformation structure may be configured by providing a slit extending spirally around an axis on a side wall of the second engagement member. In this case, it is desirable that the slit has a length of 1.5 rounds or more. Further, the elastic deformation structure makes it possible to increase or decrease the elastic restoring force according to the distance. For example, in the case where the elastic deformation structure is configured by providing a spirally extending slit on the side wall, the entire elastic deformation structure of the elastic deformation structure is not affected by the elastic deformation range in which the gap between the slits is not lost. The generated elastic restoring force provides a relatively small holding force. When elastically deforming until at least a part of the gap of the slit disappears, a part of the elastically deforming structure deforms the constituent material of the second engaging member. A relatively large holding force is brought about by not being elastically deformed any more by the yield strength.

  In the present invention, the second engagement member is guided to be movable only in a direction along the axis to a position on the pair of contact surfaces with respect to the elastic deformation structure. It is preferable to provide. The guided portion of the second engagement member is configured so that the pair of contact surfaces can move only in the direction along the axis regardless of the elastic deformation mode of the elastic deformation structure. Therefore, the contact surface comes into contact with the second shaft-shaped member accurately and with good reproducibility, and as a result, the holding force applied to the second shaft-shaped member can be stabilized. The guided portion is guided by the inner surface of the inner housing portion of the first engaging member when the second engaging member is housed inside the first engaging member as will be described later. The present invention is not limited to such an embodiment. For example, the guided portion of the second engagement member may be guided by the inner surface of the shaft hole of the intramedullary nail.

  In the present invention, the second engagement member is disposed inside a first engagement member constituting the first holding mechanism, and the first engagement member is the second engagement member. An inner housing portion for housing the inner housing portion, a concave outer shape portion for avoiding the pair of second transverse holes, and the inner housing portion and the pair of second transverse holes provided in the concave outer shape portion. A pair of side opening regions that communicate with each other, and the pair of contact surfaces of the second engaging member face the pair of second transverse holes through the pair of side opening regions, respectively. It is preferable.

  In this case, the second engagement member has a guided portion guided by the first engagement member so that the pair of contact surfaces can move only in the direction along the axis. It is preferable. The guided portion of the second engagement member is configured so that the pair of contact surfaces can move only in the direction along the axis in the inner housing portion of the first engagement member. As a result, the contact surface comes into contact with the second shaft-shaped member accurately and with good reproducibility, and as a result, the holding force applied to the second shaft-shaped member can be stabilized. The guided portion is in contact with the tip of the second engagement member provided with the pair of contact surfaces so that the movement direction of the pair of contact surfaces can be regulated. It is desirable to be provided in a portion other than the surface, for example, the outer surface portion on the tip side of the contact surface, but the present invention is not limited to such a mode, for example, from a pair of contact surfaces Also, it may be formed on the base end side.

  In the present invention, the positioning member is disposed closer to the proximal end portion than the second engagement member in the shaft hole, and is disposed at a predetermined positioning position with respect to the intramedullary nail. It is preferable that the second engaging member is engaged with the second shaft-like member inserted through the second transverse hole. In this case, the positioning member is connected to the regulated portion whose position is regulated by abutting a predetermined regulating portion provided in the shaft hole of the intramedullary nail, and the second engaging member. It is desirable to have a positioning contact portion for contacting and positioning.

  In the present invention, the positioning member includes a first positioning contact portion for contacting and positioning with the first engagement member, and a second for positioning with contact with the second engagement member. It is preferable to have a positioning contact portion. In this case, it is desirable that the positioning member has an elastic deformation structure that can extend and contract a distance between the first positioning contact portion and the second positioning contact portion.

  In the present invention, it is preferable that the second engagement member is supported by the first engagement member via second urging means that urges toward the base end portion. The first engaging member is preferably supported by the intramedullary nail body via first urging means for urging the base end side. In this case, the first engaging member is set to the initial position by abutting on a holding member (the restricting portion thereof) disposed on the base end side in the shaft hole. Is desirable.

  In the present invention, the second engagement member and the positioning member are separately configured to be separable from each other, and when the positioning member is not in contact with the second engagement member, the second engagement member. It is preferable that the joint member is disposed at an initial position where it does not protrude into the second transverse hole by the second urging means. Further, the first engaging member and the positioning member are configured separately and separable from each other, and when the positioning member is not in contact with the first engaging member, the first engaging member Is preferably disposed at an initial position so as not to protrude into the first transverse hole by the first biasing means.

  In the present invention, among the opening edges of both side openings of the pair of second transverse holes opened on the surface of the intramedullary nail, provided at the opening edge portion closer to the outer diameter with respect to the second transverse hole. It is preferable to have a surface groove formed. In this case, it is preferable that the surface groove extends from the opening edge portion along the axis and reaches the base end portion.

  According to the present invention, it is possible to achieve an excellent effect that it is possible to realize an intramedullary fixation device that can enhance the effect of preventing the rotation of a fractured portion and the effect of reducing reduction by the second shaft member.

The front view (a) which shows the appearance seen from the front of a patient, which shows the appearance of the intramedullary nail of the embodiment of the intramedullary fixation device according to the present invention, and the side view (b) seen from the outside of the patient ). An enlarged longitudinal sectional view along the direction of the axis of the first transverse hole in the proximal portion of the embodiment of the intramedullary fixation device (a) and an enlarged longitudinal sectional view along the direction orthogonal to the axis of the first transverse hole ( b). It is sectional drawing (a) seen from the patient's front side of the 1st engaging member of the Example of an intramedullary fixation apparatus, and side view (b) seen from the patient's outer side. It is the bottom view (a) and top view (b) of the 1st engaging member of the Example of an intramedullary fixation apparatus. It is the side view (a) and the front view (b) which show a mode that the 1st engaging member of the Example of the intramedullary fixation apparatus was seen from the inner side of a patient. It is the side view (a) seen from the patient outer side of the 2nd engagement member of the Example of an intramedullary fixation apparatus, and sectional drawing (b) seen from the patient front side. It is the back perspective view (a) of the 2nd engagement member of the Example of an intramedullary fixation apparatus, a front perspective view (b), and explanatory drawing (c) for demonstrating the shape of the slit formed in the wall surface. It is sectional drawing (a)-(c) of three types of end caps 125A-125C. Explanatory drawing (0) which shows the non-engagement state of the 1st engagement member and the 2nd engagement member, Explanatory drawing (a) which shows the slide free state which performed only rotation control of a lug screw, and a slide free state It is explanatory drawing (b) which shows the state which locked the extra screw, and explanatory drawing (c) which shows the state which locked the lag screw. 8A is an enlarged longitudinal sectional view along the direction of the axis of the first transverse hole in the proximal portion showing the state shown in FIG. 8A, and is enlarged along the direction perpendicular to the axis of the first transverse hole. It is a longitudinal cross-sectional view (b). FIG. 8B of the embodiment shows an enlarged vertical sectional view (a) along the direction of the axis of the first transverse hole in the proximal portion and an enlargement along the direction perpendicular to the axis of the first transverse hole. It is a longitudinal cross-sectional view (b). FIG. 8C of the embodiment shows an enlarged vertical sectional view (a) along the direction of the axis of the first transverse hole in the proximal portion and an enlargement along the direction perpendicular to the axis of the first transverse hole. It is a longitudinal cross-sectional view (b). FIG. 6 is a partial cross-sectional view and a tip shape view showing a specific example of the second shaft-shaped member 20. FIG. 4 is an external view showing a specific example of the first shaft-like member 10. FIG. 3 is a cross-sectional view showing a specific example of the first shaft member 10. The top view (a) which shows the structure of the Example from which a 2nd engagement member differs, the side view (b) seen from the patient inner side, the rear view (c) seen from the patient back side, from the patient front side They are a front view (d), a side view (e), and a bottom view (f) viewed from the outside of the patient. It is contrast explanatory drawing which shows the relationship between the Example from which the 2nd engagement member differs, and the 1st engagement member. The top view (a) which shows the structure of the Example from which a 1st engagement member differs, the side view (b) seen from the patient inner side, the front view (c) seen from the patient front side, and seen from the patient outer side They are a side view (d) and a bottom view (e). It is an inside perspective view (a), an outside perspective view (b), a top view (c), and a bottom view (d) showing the appearance of an intramedullary nail. They are the front view (a) which shows the external appearance of an intramedullary nail, the right view (b), and the rear view (c). It is AA 'sectional drawing (a) and BB' sectional drawing (b) of the intramedullary nail shown in FIG.19 (c). Sectional drawing (a) which shows the structure of the Example from which an end cap differs, The top view and sectional drawing (b) of the 1st positioning member of the said end cap, and sectional drawing of the 2nd positioning member of the said end cap ( b).

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view (a) and a side view (b) showing an intramedullary nail 110 of the intramedullary fixation device 100 of the present embodiment. The front view (a) also shows the outline of the proximal femur viewed from the front of the patient.

  The intramedullary nail 110 is a so-called short nail that is inserted into the medullary cavity from the proximal end of the femur. The one shown in FIG. 1 corresponds to the left femoral proximal portion, and the one corresponding to the right femoral proximal portion has an axisymmetric shape with respect to the one shown in FIG. The intramedullary nail 110 has a proximal portion 111 that is thick and slightly inclined upward and outward, and a distal portion 112 that is thin and extends substantially vertically. The axis 111x of the proximal portion 111 and the axis 112x of the distal portion 112 intersect at a slight angle (for example, an angle within a range of 2 to 6 degrees). The detailed external shape and cross-sectional structure of this intramedullary nail 110 are shown in FIGS.

  In the proximal portion 111 of the intramedullary nail 110, an axial hole 113 having an axis substantially coincident with the axis 111x is formed so as to extend along the longitudinal direction, and has an opening 113a at the proximal end. The shaft hole 113 includes a portion formed in the proximal portion 111 having an axis substantially matching the axis 111x, and a portion formed in the distal portion 112 having an axis substantially matching the axis 112x. And have. The shaft hole 113 has a relatively large inner diameter from the opening 113 a to a portion intersecting the first transverse hole 114, but extends from the first transverse hole 114 toward the distal side, and the distal portion 112. The portion that passes through the inside of the tube and opens to the distal end has a relatively small inner diameter that allows a guide pin or a guide wire to be inserted.

  In addition, the proximal portion 111 includes a first transverse hole 114 having an inclined axis 114x extending from the outside of the femoral shaft A to the head C, and a little proximal to the first transverse hole 114. A pair of second transverse holes 115f and 115b having axial lines 115fx and 115bx disposed on the side and inclined substantially parallel to the axial line 114x are provided. Both the first transverse hole 114 and the pair of second transverse holes 115 f and 115 b communicate with the shaft hole 113 inside the intramedullary nail 110. The axis line 114x of the first transverse hole 114 intersects the axis line 111x of the shaft hole 113, but the axis lines 115fx and 115bx of the pair of second transverse holes 115f and 115b do not intersect the axis line 111x. Pass both sides in the front-rear direction.

In the illustrated example, a pair of second transverse hole 115 f, 115b is formed at a position offset offset respectively on either side of the axis 111x. The pair of second transverse hole 115 f, the axis 115fx and 115bx of 115b are configured parallel to each other. Furthermore, in the illustrated example, these axes 115fx and 115bx are also formed in parallel to the axis 114x of the first transverse hole 114. In addition, by forming such second transverse holes 115f and 115b, the pair of second shaft members 20 inserted through these holes are installed in parallel to each other. However, the present invention is not limited to such a configuration. By setting the axes 115fx and 115bx of the pair of second transverse holes 115f and 115b to be parallel to each other toward the bone head C, the neck D The pair of second shaft-like members 20 inserted into the bone head C via the head can be configured to pass through portions closer to the cortex in the front-rear direction FB. In this way, since the engaging force of the second shaft member 20 with respect to the bone can be strengthened, the rotational resistance force and the maintaining force of the reduction state can be further increased.

  On the outer surface of the intramedullary nail 110, a surface groove 111a extending along the axis 111x from the opening edge of each side opening (four in total) of the pair of second transverse holes 115f and 115b toward the proximal side. , 111b are formed. These surface grooves 111a and 111b are formed at the opening edge of the opening by applying a force to the second shaft-shaped member 20 when the second shaft-shaped member 20 is inserted through the second transverse holes 115f and 115b. Stress is concentrated, and in particular, the thinned portion of the opening edge that is closer to the outer diameter side than the second transverse holes 115f and 115b (thinner becomes thinner along the axis 115fx and 115bx toward the opening edge, and the opening edge has an acute angle. This is provided in order to prevent the opening edge portion provided in the portion) from being lost. That is, since the surface grooves 111a and 111b are provided, the opening edge portions near the outer diameter formed in the thin and acute angles of the both side openings are cut and flattened. Breakage and cracking can be prevented. In the illustrated example, the surface grooves 111a and 111b extend from the opening edge portion to the base end portion (the portion where the opening 113a of the shaft hole 113 is provided) along the axis 111x. As a result, the intramedullary nail 110 can be easily distinguished from other intramedullary nails in appearance, and an error in sorting during surgery can be avoided.

  On the other hand, the distal portion 112 is formed with a third transverse hole 116 and a fourth transverse hole 117 each having an axis (horizontal axis) substantially orthogonal to the axis 112x. Here, the third transverse hole 116 has a circular opening cross section, while the fourth transverse hole 117 has an elliptical opening cross section extending in the direction along the axis 112x.

  FIG. 2 is an enlarged longitudinal sectional view (a) showing a longitudinal section along the direction of the axis 114x of the first transverse hole 114, showing the structure in the proximal portion 111 of the intramedullary nail 110 of the present embodiment, and this It is an enlarged vertical sectional view (b) which shows the vertical cross section orthogonal to a vertical cross section. A first engagement member 121A and a second engagement member 121B are accommodated in the shaft hole 113 of the proximal portion 111. The first engagement member 121A and the second engagement member 121B are both housed and arranged in the shaft hole 113 so as to be movable along the direction of the axis 111x.

  Further, as shown in FIG. 3, the first engagement member 121 </ b> A has a flange-like base end portion 121 p that projects to the outer peripheral side, and is disposed on a stepped portion 113 d formed on the inner surface of the shaft hole 113. An elastic member (coil spring) 122A abuts against the protruding portion of the base end portion 121p from below, and biases the first engagement member 121A upward in the figure. That is, the first engagement member 121A is supported from below by the intramedullary nail 110 through the elastic member 122A.

  On the other hand, as shown in FIG. 6, the second engagement member 121B also has a flange-like base end portion 121q protruding to the outer peripheral side, and is provided so as to penetrate through the inside of the first engagement member 121A. It is accommodated in the shaft hole 121a (corresponding to the internal accommodating portion). An elastic member (coil spring) 122B is disposed on a step portion 121d formed on the inner surface of the shaft hole 121a. The elastic member 122B comes into contact with the protruding portion of the base end portion 121q from below, and The two engaging members 121B are urged upward. That is, the second engagement member 121B is supported from below by the first engagement member 121A via the elastic member 122B.

  Inside the shaft hole 113, a female screw 113b provided in a region near the opening 113a at the base end is provided. The female screw 113b has an opening 123a penetrating in the direction of the axis 111x at the center, and a holding member 123 having a male screw on the outer periphery is screwed into the female screw 113b. The holding member 123 is in contact with a stepped portion 113e provided on the base end side with respect to the housing location of the first engaging member 121A and the second engaging member 121B in the shaft hole 113, whereby the axis line It is positioned in the 111x direction. The holding member 123 is in contact with the base end 121p of the first engagement member 121A from above, and is positioned in a state where the first engagement member 121A is sandwiched between the elastic member 122A. ing. That is, the first engagement member 121A is disposed at the initial position in the shaft hole 113 of the intramedullary nail 110 by the elastic member 122A and the holding member 123. An opening edge (upper end) of the opening 123a of the holding member 123 serves as a restricting portion 123b for positioning positioning members 125A to 125C (to-be-restricted portions) described later.

  The shape of the first engagement member 121A is shown in FIGS. The first engagement member 121A has a cylindrical shape as a whole having a shaft hole 121a. The base end portion 121p of the first engagement member 121A is formed in an annular frame shape projecting outward in the radial direction, and a female screw 121b is formed on the inner surface thereof. The female screw 121b is an engagement structure for screwing the first engagement member 121A out of the shaft hole 113 with the extraction tool. Further, a smooth inner surface 121c of a cylindrical surface is formed on the distal side of the female screw 121b. The slide inner surface portion 121c guides the base end portion 121q of the second engagement member 121B accommodated in the shaft hole 121a in a slidable manner. The stepped portion 121d is formed on the distal side of the slide inner surface portion 121c.

  On the distal side of the stepped portion 121d, the first engaging member 121A includes a pair of outer shape portions 121e that are squeezed into a concave shape along the inclined direction of the axis 115x on both sides of the axis 111x. Yes. The pair of external parts 121e are configured to avoid the pair of second transverse holes 115f and 115b when the first engagement member 121A is disposed in the shaft hole 113. That is, the first engagement member 121A has a shape that does not protrude into the pair of second transverse holes 115f and 115b in a normal arrangement in the shaft hole 113. Each of the pair of external portions 121e is provided with a pair of side opening regions 121f each provided with an inclined opening edge along the inclined direction of the axis 115x. The pair of side opening regions 121f are opened such that the shaft hole 121a communicates with the pair of second transverse holes 115f and 115b.

  A pair of longitudinal grooves 121 s are provided on the outer surfaces of both sides in the front-rear direction of the first engaging member 121 A, and the inside of the two anti-rotation pins 124 attached to the wall surface of the intramedullary nail 110 in these longitudinal grooves 121 s. When the ends are fitted, the first engagement member 121A is configured to be movable in the direction of the axis 111x, but is restricted from rotating around the axis 111x.

  The portion of the first engagement member 121A on the distal side of the outer shape portion 121e has an outer shape that is slightly swelled outward in the radial direction and then narrowed down toward the tip engagement portion 121g. The tip engaging portion 121g is inclined along the axis 114x of the first transverse hole 114 as a whole, and is engaged with the outer surface of the first shaft member 10 inserted through the first transverse hole 114. Tip engagement portions 121h and 121i are provided on both sides in the direction along the axis 114x of the shaft hole 121a. The distal end engaging portion 121h is disposed on the outer side of the patient in the intramedullary nail 110, and the distal end engaging portion 121i is disposed on the inner side of the patient. Any of the front end engaging portions 121h and 121i engages with an engaging groove 17 formed on the outer surface of the first shaft-shaped member 10, and the axis 114x of the first shaft-shaped member 10 with respect to the intramedullary nail 110 is obtained. Regulates rotation around. However, by adjusting the engagement depth, a slide-free state in which the first transverse hole 114 can slide in the direction of the axis 114x and a slide lock state in which the slide in the direction of the axis 114x is also regulated. Both are configured to be feasible. Specifically, the front engagement portions 121h and 121i are fitted with a fine surface uneven engagement structure 18 (see FIG. 14) formed on the inner surface of the engagement groove 17, and the slide lock state described above. Is provided with a fine surface uneven engagement structure formed so as to surely regulate the sliding in the direction of the axis 114x.

  The shape of the second engagement member 121B is shown in FIGS. The second engaging member 121B is formed in a cylindrical shape as a whole having a shaft hole 121j. However, if there is no need to insert the intramedullary nail 110 along the guide pin, the structure without the shaft hole 121j may be used. The base end portion 121q of the second engagement member 121B is configured in an annular frame shape projecting outward in the radial direction. A longitudinal groove 121r is formed in a part of the angular range of the base end part 121q. This vertical groove 121r engages with a rotation restricting pin 121o (see FIG. 2) attached so as to penetrate the base end portion 121p of the first engaging member 121A, and the second engaging member 121B becomes the second engaging member 121B. While being configured to be movable in the direction along the axis 111x with respect to one engaging member 121A, it is restricted from rotating around the axis 111x. In addition, a pair of contact surfaces 121u and 121v having a concave curved surface (in the illustrated example, a concave cylindrical surface) are formed on the distal end engaging portion 121k on the opposite side to the base end portion 121q. The pair of contact surfaces 121u and 121v are along the inner surfaces of the pair of second transverse holes 115f and 115b when the second engagement member 121B moves to the distal side in the direction of the axis 111x ( In the illustrated example, it has a surface shape (corresponding to cylindrical surfaces centered on the axes 115 fx and 115 bx), and makes contact with the convex curved outer surfaces of the pair of second shaft members 20 in close contact with each other.

  Further, in the illustrated example, the pair of contact surfaces 121u and 121v are surfaces having contact regions with respect to the second shaft-shaped member 20 having an extended shape along the axis lines 115fx and 115bx of the second transverse sections 115f and 115b. Shaped. As a result, the contact area with the second shaft-shaped member 20 can be increased, so that the second engagement member 121B can apply a large holding force to the second shaft-shaped member 20. .

  In the second engaging member 121B, a cylindrical side wall exists between the base end part 121q and the front end engaging part 121k, and the side wall is spiral around the axis 121Bx coinciding with the axis 111x. The slit 121t is formed, thereby providing an elastic deformation structure that allows the second engagement member 121B to expand and contract in the direction of the axis 111x. The slit 121t has a gap (typically a gap of about 1 to 2 mm) in the direction of the axis 111x, which is provided in a constant manner in a spiral extending direction. FIG. 7C shows a planar shape of the slit 121t drawn by a solid line and a dotted line (ring-shaped drawing part on the outer peripheral side) and a start point 121t1 to an end point 121t2 of the slit 121t drawn by a two-dot chain line. It is explanatory drawing which shows a spiral path | route (the spiral illustration part of an inner peripheral side) correspondingly in the inside and outside of a radial direction. The slit 121t is formed to extend in a spiral shape over a range exceeding 1.5 turns around the axis 121Bx.

  The angle range in which the slit 121t is formed is symmetrical with respect to the pair of left and right contact surfaces 121u and 121v. That is, considering the symmetry axis 121m perpendicular to the axis 121Bx, which is set between the pair of contact surfaces 121u and 121v and becomes the symmetry axis of these contact surfaces 121u and 121v, the formation angle range of the slit 121t is as follows. It is axially symmetric with respect to the symmetry axis 121m. Specifically, the slit 121t is formed in a continuous spiral shape from the start point 121t1 on the distal end side to the end point 121t2 on the proximal end side, but the angular difference between the angular position of the start point 121t1 of the slit 121t and the symmetry axis 121m. And the angular difference between the angular position of the end point 121t2 and the symmetry axis 121m is the same. As a result, the respective elastic deformation amounts of the both side portions in the front-rear direction generated when the pair of contact surfaces 121u and 121v contact the second shaft member 20, respectively, and the elastic pressing force generated accordingly. Are configured to be equal to each other.

  In addition, the elastic deformation structure of the second engagement member 121B is such that the amount of elastic deformation of both side portions in the front-rear direction is different when the force applied to one contact surface 121u and the other contact surface 121u is different. It has elastic deformation characteristics that are allowed to be different from each other. Therefore, there may be a case where the positions of the second shaft-like members 20 inserted through the pair of second transverse holes 115f and 115b are slightly different from each other due to errors in parts processing, etc. Due to the elastic deformation characteristics, the pair of second shaft members 20 can receive substantially the same holding force from the second engagement member 121B. Further, the elastic deformation characteristic is that the second shaft-like member 20 is inserted only into one second transverse hole 115f, and the second shaft-like member 20 is inserted into the other second transverse hole 115b. Even in such a situation, the second engagement member 121B can give a sufficient holding force to the one second shaft-shaped member 20. The holding force at this time is the same as the holding force received by each second shaft-shaped member 20 when the second shaft-shaped member 20 is inserted through both the pair of second transverse holes 115f and 115b. Preferably there is. Note that the holding force when only the one second shaft-shaped member 20 is inserted is that the second shaft-shaped member 20 is inserted into both the pair of second transverse holes 115f and 115b. In this case, it may be lower than the holding force received by each second shaft-shaped member 20, but in this case, it is preferably 80% or more of the holding force, and more preferably 90% or more.

  As shown in FIG. 2, when an end cap 125 described later does not function and the first engagement member 121A is in the initial position positioned by the elastic member 122A and the holding member 123, the first engagement member 121A The tip engaging portion 121g does not protrude into the first transverse hole 114 and does not conflict with the first shaft member 10 inserted through the first transverse hole 114. At this time, when the second engagement member 121B is supported by the first engagement member 121A via the elastic member 122B and is in an initial position that is not restricted in the direction of the axis 111x, The front end engaging portion 121k of the engaging member 121B does not protrude into the second transverse holes 115f and 115b, and does not conflict with the second shaft member 20 inserted through the second transverse holes 115f and 115b. . The holding state of the first shaft-like member 10 and the second shaft-like member 20 at this time is shown in the explanatory view of (0) of FIG.

  FIGS. 8A to 8C are longitudinal sectional views showing examples of the shape of the end cap 125 attached to the proximal end portion of the intramedullary nail 110 of the present embodiment. The end cap 125 corresponds to the positioning member, and includes a head portion 125a provided with a male screw 125b screwed into a female screw 113b formed in the shaft hole 113 of the intramedullary nail 110, and the direction of the axis 125x from the head portion 125a. And a projecting portion 125e projecting on the surface. A tool engagement structure 125d (a structure that can be connected to a rotary operation tool such as a wrench, a hexagonal hole in the illustrated example) is formed in the head 125a. The protruding portion 125e protrudes with an annular step surface 125c, which is a plane orthogonal to the axis 125x, interposed between the head 125a and an annular shape that is a plane orthogonal to the axis 125x at the tip. A tip protrusion 125g protruding with the stepped surface 125f interposed is provided.

  The various end caps 125 shown in FIGS. 8A to 8C are inserted into the opening 123 a of the holding member 123, and the restriction portion 123 b that is the upper opening edge of the opening 123 a of the holding member 123. (See FIG. 2). Further, these end caps 125 are common in that they have the head portion 125a and the protruding portion 125e and are provided with the step surfaces 125c and 125f. The step surface 125c corresponds to a regulated portion in which the position in the intramedullary nail 110 is regulated by contacting the regulating portion 123b when the end cap 125 is disposed in the shaft hole 113. Further, the step surface 125f and the protruding portion 125g correspond to a positioning contact portion having a function of regulating the position of the first engaging member 121A and the second engaging member 121B in the direction of the axis 111x. The end cap 125 is configured to be usable as a positioning member.

  When the end cap 125A shown in FIG. 8A is screwed into the shaft hole 113 and the step surface 125c comes into contact with the restricting portion 123b of the holding member 123, the step surface 125f becomes the first engaging member 121A. To the distal side to form a first positioning contact portion for positioning the first engagement member 121A in the direction of the axis 111x with the elastic member 122A. Further, since the tip protrusion 125g protrudes further to the distal side than the stepped surface 125f, the tip surface pushes the second engagement member 121B to the distal side, and the first protrusion 125g is pushed between the elastic member 122B. It becomes the 2nd positioning contact part which positions the 2 engaging member 121B in the direction of the axis 111x.

  FIG. 10 shows a state of the proximal portion 111 of the intramedullary nail 110 when the end cap 125A is mounted as described above, and holding of the first shaft member 10 and the second shaft member 20 at that time. The state is shown in FIG. At this time, the front end engaging portion 121g of the first engaging member 121A enters the engaging groove 17 formed on the outer surface of the first shaft-shaped member 10, and as a result, the first shaft-shaped member 10 rotations are restricted. However, since the front end engaging portion 121g is not engaged with the bottom surface of the engaging concave groove 17, the first shaft-like member 10 is in a slide-free state in which it can slide in the direction of the axis 114x of the first transverse hole 114. is there.

At this time, the tip engagement portion 121k of the second engagement member 121B is lowered, and the pair of contact surfaces 121u and 121v enter the pair of second transverse holes 115f and 115b, respectively, and the second transverse hole. It closely adheres to the outer surface of the pair of second shaft members 20 inserted through 115f and 115b. However, since the amount of descent along the axis 111x of the second engagement member 121B at this time is a slight amount corresponding to the height difference between the step surface 125f and the tip protrusion 125g, the pair of contact surfaces 121u, When 121v contacts the outer surface of the corresponding second shaft member 20, the gap between the slits 121t only slightly decreases. Therefore, the second shaft-shaped member 20 receives an elastic restoring force corresponding to the slight elastic deformation amount of the side wall as a holding force from the pair of contact surfaces 121u and 121v of the second engaging member 121B. That is, the holding force that the second shaft member 20 receives from the tip engaging portion 121k of the second engaging member 121B at this time is merely an elastic restoring force generated from the elastic structure of the second engaging member 121B. Therefore, the second shaft-shaped member 20 is not completely fixed in the directions of the axes 115fx and 115bx, and the second shaft-shaped member 20 detached from the bone fragment (bone head C) is not attached to the intramedullary nail 110. Therefore, the holding force is sufficient to prevent it from falling outside. Therefore, since the second shaft-like member 20 has a holding force that can slide with respect to the intramedullary nail 110 as the bone fragment moves, it occurs in the vicinity of the proximal end B of the femur and the neck D. The second shaft-shaped member 20 moves together with the bone head C in accordance with the shortening without disturbing the shortening of the bone fragment end that occurs in the healing process of the broken fracture site. This state is hereinafter simply referred to as “elastic holding state”.

  The end cap 125B shown in FIG. 8B has stepped surfaces 125c and 125f at the same position as the end cap 125A, but differs from the end cap 125A in that the protruding amount of the tip protrusion 125g is large. For this reason, since the positioning action of the first engagement member 121A is the same as that of the end cap 125A, the holding state of the first shaft member 10 is also the same slide-free state as described above, and the description thereof is omitted.

  On the other hand, as shown in FIG. 9B and FIG. 11, the second engagement member 121B has a difference in height between the stepped surface 125f of the end cap 125B and the tip protrusion 125g when the end cap 125A is used. Compared to the distal side. As a result, the second engagement member 121B is compressed between the end cap 125B and the second shaft-shaped member 20, and the gap between the slits 121t is further reduced, thereby holding force in the elastic holding state. The second shaft-like member 20 is pressed with a strong holding force exceeding the above. This strong holding force makes the pair of shaft-like members 20 substantially fixed to the intramedullary nail 110 during and after the operation. This state is hereinafter simply referred to as “elastic fixed state”. Although the deformation | transformation aspect of the said elastic deformation structure when implement | achieving the said elastic fixation state is not specifically limited, In the example of illustration, it is a patient's outer side in the 2nd engagement member 121B by the compression action by the end cap 125B. When there is no gap between the slits 121t at the angular position on the side of the elastic member, the elastic restoring force increases rapidly according to the deformation resistance of the constituent material of the second engagement member 121B at the angular position, and the holding force is also increased. Will increase.

  Next, in the end cap 125C shown in FIG. 8C, the position of the step surface 125c is slightly proximal (upward in the drawing) than the case of the end caps 125A and 125B, and the position of the step surface 125f is The end caps 125A and 125B are slightly distal (downward in the figure). Thus, when the end cap 125C is screwed in until the stepped surface 125c hits the upper surface of the holding member 123, the first engagement member 121A is more than the case of the end caps 125A and 125B, as shown in FIG. 9C. Since the distal end engaging portion 121g hits the bottom surface of the engaging groove 17 of the first shaft-like member 10 and is pushed into the distal side, it fits into the fine uneven engaging structure 18 provided on the bottom surface. Therefore, the first shaft-like member 10 is not only restricted in the rotational direction described above but also regulated in the direction of the axis 114x, and is in a slide lock state.

  On the other hand, the end cap 125C is provided with a tip convex portion 125h projecting further distally at the center of the tip projection 125g. For this reason, a step surface (hereinafter referred to as a step surface 125g) is formed between the tip convex portion 125h and the tip protrusion 125g. Thereby, the stepped surface 125g pushes the proximal end portion 121q of the second engagement member 121B to the distal side, and the tip convex portion 125h is inserted into the shaft hole 121j of the second engagement member 121B. . The step surface 125g is in the direction of the axis 111x coinciding with the end surface position of the tip protrusion 125g of the end cap 125B when the first shaft-shaped member 10 is in the slide lock state by the first engagement member 121A. It is comprised so that it may be arrange | positioned in position. As a result, as shown in FIG. 9C, the second engagement member 121B is in the elastically fixed state as in the case of using the end cap 125B.

  FIG. 12 shows a state in which a slight gap exists between the stepped surface 125c that is the regulated portion of the end cap 125C and the regulating portion 123b of the holding member 123. From this state, the end cap is shown. Since 125C can be further screwed in, the first engagement member 121A and the second engagement member 121B can be pushed further to the distal side, and the slide lock state and the elastic fixed state can be reliably realized. It is like that.

  FIG. 13 is a partial cross-sectional view and a front end view showing an example of the second shaft-shaped member 20. The second shaft-shaped member 20 includes a shaft portion 21 having a circular cross section, a screw portion 22 having a cutting edge at a distal end, and a head portion 23 having a tool engagement structure 23a provided at a proximal end. In this embodiment, the outer peripheral surface of the shaft portion 21 is a cylindrical surface having the same diameter in the direction of the axis, and the pair of contact surfaces 121u and 121v of the tip engaging portion 121k of the second engaging member 121B is exactly the same. The surface shape can be in close contact with the surface. The second shaft-shaped member 20 is not limited to a bone screw as in the present embodiment, and may be configured by a simple shaft-shaped pin, a guide pin, or the like.

  14 and 15 are an external view and a cross-sectional view showing an example of the first shaft-like member 10. The first shaft-shaped member 10 includes a shaft portion 11 having a circular cross section, a screw portion 12 having a cutting edge at the tip, and a base portion 13 having a tool engagement structure 13a provided at the base end. In this embodiment, a shaft hole 10a penetrating in the direction of the axis is formed so that it can be introduced (screwed) into the bone along a guide pin installed in advance. On the outer peripheral surface of the shaft portion 11, a plurality of engagement concave grooves 17 formed long along the axial direction are provided around the axis (four in the illustrated example at intervals of 90 degrees). The engagement concave groove 17 has a concave arc-shaped groove cross section on a cross section orthogonal to the axis, and has a convex arc-shaped engagement cross section on the same cross section. It is comprised so that it may fit with the said front-end | tip engaging part 121h and 121i of the joining part 121g. Further, on the inner surface of the engagement concave groove 17, an engagement structure 18 configured to have a surface irregularity in the axial direction is provided. The engagement structure 18 regulates the sliding operation in the direction of the axis of the first shaft-shaped member 10 when the engagement structure 18 is engaged with the engagement structure having the surface unevenness provided in the tip engagement portions 121h and 121i, respectively. The slide lock state is surely realized.

  In the present embodiment described above, in the intramedullary nail 110, the second transverse holes 115f and 115b formed on the proximal side of the first transverse hole 114 do not intersect the axis 111x, and the axis 111x Axis lines 115fx and 115bx which are shifted to both sides are provided. Therefore, as shown in FIGS. 1C and 1D, the position where the second shaft-shaped member 20 passes through the femoral head C and neck D of the femur is relative to the first shaft-shaped member 10. The positions are shifted in the front-rear direction FB of the patient. Therefore, since the second shaft-shaped member 20 passes through a position close to the cortical portion of the neck D in comparison with the case where the second shaft-shaped member 20 is disposed so as to pass over the axis 111x, the second shaft-shaped member 20 is engaged with the fracture portion. The strength is increased, and the effect of preventing rotation and the effect of maintaining reduction can be enhanced.

  In particular, when the first shaft-like member 10 is a screw, during operation, the bone head C is screwed around the axis 114x in the same direction as the screwing direction when the first shaft-like member 10 is screwed. Receive the turning force. However, in the case of FIG. 1, the left femur is shown, but the directions of the rotational force are opposite to each other between the left femur and the right femur. Therefore, in this case, the first shaft-like member 10 is screwed after the second shaft-like member 20 is introduced, so that the cortex is opposite to the side receiving the turning force according to the direction of the turning force. When the first shaft-shaped member 10 is screwed in the right direction in the second shaft-shaped member 20 (FIGS. 1C and 1D) where the portion exists, the front F side of the front-rear direction FB in the drawing. The second shaft-like member 20) can reliably receive mainly the rotational force.

  Further, when there is a fracture on the outside near the proximal end B of the femur or on the inside near the neck D, the bone head C tends to be compressed toward the front F in the body. In order to maintain the reduction state, a force for pushing back the bone head C is required. At this time, the above-mentioned rotational force can be received more reliably by the second shaft-like member 20 on the rear B side in the patient front-rear direction FB. As described above and as will be described later, when one of the two second shaft-shaped members 20 is particularly effective in preventing rotation and maintaining reduction. In this case, only the one second shaft-shaped member 20 may be inserted into one second transverse hole, and the second shaft-shaped member 20 may not be inserted into the other second transverse hole.

  In addition, as shown in FIGS. 1C and 1D, the first shaft-shaped member 10 is ideally inserted at the center position in the front-rear direction FB, but in reality, the first shaft 10 The shaped member 10 may be inserted at a position shifted to either the front F or the rear B in the front-rear direction FB. In such a case, when a load is applied to the bone head C during rehabilitation after surgery, depending on which direction of the front-rear direction FB the first shaft member 10 is displaced forward F When it shifts to the back, a rotating force is generated in the bone head C based on the load, and a rotating force in a direction in which the portion at the rear B is directed downward is generated. At this time, the rotational force in the direction in which the rear B portion is directed downward is surely received by the resistance of the cortical portion on the front F by the second shaft-like member 20 mainly on the front F side. The rotational force in which the portion is directed downward is surely received by the resistance of the cortical portion on the rear B side by the second shaft member 20 mainly on the rear B side.

  Further, in the present embodiment, the second shaft-like member 20 receives a holding force from the movable second engaging member 121 </ b> B disposed in the shaft hole 113 of the intramedullary nail 110, thereby causing the intramedullary nail 110. Held against. Therefore, compared with the case where the second shaft-like member 20 having a male screw structure engaged with the female screw structure is held by the female screw structure formed on the inner surfaces of the second transverse holes 115f and 115b, the second shaft The holding force of the member 20 can be made variable, and the amount of protrusion of the second shaft member 20 toward the bone head C (position in the direction of the axes 115fx and 115bx) can be adjusted. For this reason, it becomes possible to take various measures according to the fracture situation, the degree of progression of osteoporosis, and the like.

  In the present embodiment, a second engagement member 121B that engages with the second shaft-shaped member 20 is accommodated inside the first engagement member 121A that engages with the first shaft-shaped member 10. . With this structure, the outer diameter of the first engagement member 121A can be ensured to be large, so that the engagement area with respect to the first shaft member 10 can be sufficiently secured, and a sufficient fixing force can be obtained. Sufficient rigidity that can withstand this fixing force can be secured.

  In the mutual housing structure between the first engagement member 121A and the second engagement member 121B as described above, the pair of contact surfaces 121u and 121v of the second engagement member 121B is the second shaft-shaped member. In this embodiment, as the outer shape of the first engagement member 121A, a pair of outer portions narrowed down in a concave shape so as to avoid the pair of second transverse holes 115f and 115b. 121e is formed, and the shaft hole 121a (inner housing portion for housing the second engaging member 121B in the first engaging member 121A) and the second transverse hole 115 are communicated with these outer portions 121e, respectively. A pair of side opening regions 121f are provided.

  In the present embodiment, the tip engagement portion 121k of the second engagement member 121B has a tip shape that is inclined in a direction along the pair of axes 115x. In addition, on both sides of the axis 121Bx of the tip engaging portion 121k, the shape is inclined along the axes 115fx and 115bx and extended in the direction of the axis, and the inner surfaces of the pair of second transverse holes 115f and 115b By providing the concave curved contact surfaces 121u and 121v along the shape, a sufficient contact area can be secured and a sufficient holding force can be applied to the second shaft member 20. Composed.

  In the elastic deformation structure constituted by the slit 121t formed on the side wall of the second engagement member 121B, the pair of contact portions 121u and 121v are equally held with respect to the pair of second shaft members 20. An elastic holding state that provides a relatively small holding force based on an elastic restoring force corresponding to a relatively small amount of elastic deformation of the elastic deformation structure, and a relatively large deformation of the elastic deformation structure It is possible to switch between an elastic fixed state that provides a relatively large holding force obtained corresponding to the amount or deformation amount exceeding the elastic limit.

  Further, since the elastic deformation structure has an elastic deformation characteristic that allows the elastic deformation amounts of both side portions provided with the pair of contact surfaces 121u and 121v to be different from each other, the pair of second transverse holes 115f, Even when the second shaft-shaped member 20 is inserted only into one of the 115b, a sufficient holding force can be applied to the one second shaft-shaped member 20. Further, this elastic deformation characteristic is such that when there is a slight difference in the position and shape of the pair of second shaft members 20 inserted through the pair of transverse holes 115f and 115b, the pair of second shaft members 20. There is also an effect of keeping the holding force against each other evenly.

  16 to 18 show a configuration example of the first engagement member 121A ′ and the second engagement member 121B ′ different from the above embodiment. In this configuration example, the tip engagement portion 121k ′ of the second engagement member 121B ′ formed in a substantially cylindrical shape as a whole does not protrude into the second transverse holes 115f and 115b at the initial position. The concave outer surface portions are provided on the left and right sides, respectively, and a part of the proximal end side of these concave outer surface portions is a pair of contact surfaces 121 u ′ and 121 v ′ that contact the second shaft member 20. In addition, the guided portion 121n ′ which is a tip portion excluding the tip engaging portion 121k ′ which is a concave outer surface portion formed along the hole space of the second transverse holes 115f and 115b is the first engaging member. The shaft hole 121a 'is accommodated in the tip end portion of the shaft hole 121a' of the combined member 121A 'and is movable in the direction along the axis 121Ax' so that the second engagement member 121B 'can move. Guided by the inner surface.

  When configured as described above, the second engagement member 121B ′ has not only the base end portion 121q ′ but also the guided portion 121n ′ within the shaft hole 121a ′ of the first engagement member 121A ′. Therefore, even when the elastic deformation structure constituted by the slit 121t ′ is elastically deformed, the posture of the tip engagement portion 121k ′ (the second engagement member) regardless of the elastic deformation mode. The posture of the guided portion 121n ′ of 121B ′ is precisely maintained in the posture along the axis 121Ax ′. Therefore, in this embodiment, the guided portion 121n ′ of the second engagement member 121B ′ is guided by the inner surface of the shaft hole 121a ′ of the first engagement member 121A ′, and the second engagement member 121B ′ is , And is configured to be deformed only in the direction of the axis 121Ax ′. Therefore, the pair of contact surfaces 121u ′ and 121v ′ move only in the direction along the axis 121Ax ′, and contact with the outer surface of the second shaft-shaped member 20 in an accurately aligned posture. The holding force for the second shaft member 20 can be generated accurately and with good reproducibility, and the contact area can be ensured, so that the holding force can be generated more firmly.

  In particular, when the second shaft-shaped member 20 is inserted through only one of the pair of transverse holes 115f and 115b, only one of the pair of contact surfaces 121u ′ and 121v ′ is the second shaft-shaped. The member 20 comes into contact with the other, and the other does not come into contact. In this case, in the first embodiment, the distal end engaging portion 121k of the second engaging member 121B is deformed in a shape bent in the front-rear direction FB, whereas in this embodiment, the second engaging member 121B is deformed. ′ Does not cause the deformation of the mode in which the axis 121Bx ′ bends, so that the holding force with respect to the second shaft-shaped member 20 on one side is unlikely to decrease, and can be more firmly fixed.

  FIG. 22 shows a structure of an end cap 125D that is different from the above embodiment. Unlike the end caps 125A to 125C, the end cap 125D includes a first positioning member 125Dp configured by a cylindrical outer frame portion having a head portion 125Da and a protruding portion 125De, and the first positioning member. And a second positioning member 125Dq housed in 125Dp. Here, the first positioning member 125Dp is a member for positioning the first engagement member 121A, and the second positioning member 125Dq is a member for positioning the second engagement member 121B. It is. In the end cap 125D of the present embodiment, the first positioning member 125Dp and the second positioning member 125Dq are fixed to each other to constitute an end cap 125D that is an integral positioning member. Specifically, the upper portion 125Du of the second positioning member 125Dq is fitted into the annular concave groove formed in the inner surface of the shaft hole of the first positioning member 125Dp via the retaining ring 125Dr. However, as in the example described later, the first positioning member and the second positioning member may be coupled so as to be relatively movable by a screwing structure or the like.

  In the first positioning member 125Dp, a male screw 125Db similar to the above is provided on the outer periphery of the head 125Da, and a tool engagement structure 125Dd that opens to the proximal end is provided similarly to the above. The protrusion 125De protrudes with an annular step surface 125Dc interposed. The step surface 125Dc is a regulated portion that is positioned in contact with the upper edge (regulating portion) of the holding member 123. Further, the projecting portion 125De has a cylindrical shape, the tip is open, and an annular end surface around the projecting portion 125D is a step surface 125Df that contacts the first engagement member 121A and positions the first engagement member 121A. This step surface 125Df corresponds to a first positioning contact portion. A second positioning member 125Dq is accommodated in the protrusion 125De.

  The second positioning member 125Dq includes an annular step surface 125Dg shown in the drawing adjacent to the inside of the step surface 125Df at the tip portion, and has a tip convex portion 125Dh protruding from the inside of the step surface 125Dg. The step surface 125Dg corresponds to a second positioning contact portion that positions the second engagement member 121B. Further, in the second positioning member 125Dq, between the upper portion 125Du connected to the first positioning member 125Dp (fixed in the illustrated example) and the step surface 125Dg for positioning the second engagement member 121B, An elastic deformation structure is formed by a slit 125Dt formed on the side wall and extending spirally. That is, the end cap 125D, which is a positioning member, is provided with an elastic deformation structure between the first positioning contact portion (the step surface 125Df) and the second positioning contact portion (the step surface 125Dg). The elastic deformation of the elastic deformation structure is configured such that the distance between the positioning contact portions can be expanded and contracted in the direction of the axis 125Dx. Therefore, the elastic deformation structure is provided between the position of the first engagement member 121A that holds the first shaft-shaped member 10 and the position of the second engagement member 121B that holds the second shaft-shaped member 20. A certain margin can be provided by elastic deformation. The second positioning member 125Dq is provided with a shaft hole. The shaft hole 125Dv shown in FIG. 22A is a shaft hole having a bottom, and the shaft hole 125Dv ′ shown in FIG. However, it may have any structure.

  The end cap 125D has a function corresponding to the end cap 125C. That is, the first engagement member 121A is positioned by the step surface 125Df to realize the slide lock state of the first shaft member 10, and the second engagement member 121B is positioned by the step surface 125Dg. Thus, the elastically fixed state of the second shaft member 20 is realized. In this case, in order to realize both the slide lock state of the first shaft member 10 and the elastic fixing state of the second shaft member 20, the first engagement member 121A and the second engagement member Both 121B need to be positioned precisely. Therefore, when trying to position both the first engagement member 121A and the second engagement member 121B using the rigid end cap 125C as described above, the first engagement member 121A uses the first end. One of the slide lock state of the shaft-like member 10 and the state of elastic fixation of the second shaft-like member 20 by the second engagement member 121B can be realized, but the other cannot be realized. In particular, since the positional relationship of the slide lock state between the first shaft member 10 and the first engagement member 121A is a strict contact relationship, the position margin for realizing the slide lock state is extremely small. . For this reason, although the said elastic fixation state is realizable, the situation which cannot implement | achieve the said slide lock state tends to arise.

  However, in the present embodiment, as described above, an elastic deformation structure is provided between the connection position of the second positioning member 121q with respect to the first positioning member 121p and the step surface 125Dg for positioning the second engagement member 121B. Therefore, if the elastic restoring force of the elastic deformation structure is large enough to realize the elastic fixing state with respect to the second shaft-like member 20 by the second engagement member 121B, the elastic deformation range of the elastic deformation structure is sufficient. Since there is a margin in the positioning relationship between the first engagement member 121A and the second engagement member 121B, it is possible to avoid the occurrence of the above situation.

  The end cap 125D in the illustrated example is intended to be used as a substitute for the end cap 125C. However, the first positioning member 125Dp similar to the above is used when used as a substitute for the end cap 125A or 125B. And the second positioning member 125Dq, or the second positioning member 125Dq may be provided with an elastic deformation structure. By doing in this way, the position margin between the 1st engaging member 121A and the 2nd engaging member 121B can be obtained like the above. However, in these cases, it is necessary to set the positioning portions (positioning contact portions) for the first engagement member 121A and the second engagement member 121B to positions corresponding to the end caps 125A and 125B. .

  This embodiment is further expanded, and, as described above, the first positioning member 125Dp and the second positioning member 125Dq are configured to be relatively movable in the direction of the axis 125Dx, whereby the first engaging member 121A is configured. And the second engagement member 121B can be positioned separately. For example, the position in the axial direction can be relatively adjusted by screwing the female screw of the first positioning member 125Dp and the male screw of the second positioning member 125Dq and changing the screwing depth. Further, as the second engagement member 121B positioned by the second positioning member 125Dq having an elastic deformation structure, an engagement member not having the elastic deformation structure can be used. However, in this case, the elastic deformation member provided on the second positioning member 125Dq needs to have an elastic deformation characteristic capable of realizing the elastic holding state and the elastic fixing state. Further, by extending the second positioning member 125Dq downward, it is possible to use the lower part of the second positioning member 125Dq instead of the second engaging member 121B. In this case, the first positioning member 125Dp corresponds to the positioning member, and the second positioning member 125Dq corresponds to the second engaging member. In this case as well, the elastic deformation member needs to have an elastic deformation characteristic capable of realizing the elastic holding state and the elastic fixed state.

  Note that the intramedullary fixation device according to the present invention is not limited to the above-described illustrated examples, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the case where two second shaft-shaped members 20 are used has been described. However, only one of the second shaft-shaped members 20 can be used as necessary. Even in this case, the second engaging members 121B and 121B ′ can reliably hold the second shaft member 20 on one side by guiding the elastic deformation characteristics of the elastic deformation structure and the guided portion 121n ′. In particular, in this embodiment, when holding the two second shaft-shaped members 20 and when holding only one of the second shaft-shaped members 20, the same is true in any of the above-described holding modes. Holding power can be given. In addition, the outer peripheral surface of the second shaft-shaped member 20 is not limited to the cylindrical surface or the convex curved surface, and may have various arbitrary shapes. It is desirable that the pair of contact surfaces 121u and 121v of the tip engagement portion 121k of the second engagement member 121B be configured to have a surface shape.

  In the above embodiment, the first holding mechanism includes the first engaging member 121A and the end cap 125 that is a positioning member, and the second holding mechanism is the second engaging member 121B and the end that is a positioning member. The first engagement member 121A and the end cap 125 that is a positioning member are made of different members, and the second engagement member 121B and the end cap 125 that is a positioning member are made different. Although it consists of a member, this invention is not limited to such a structure. For example, the first engagement member 121A is rotatably connected to a positioning member such as the end cap 125, and the male screw portion of the positioning member is screwed into the female screw of the shaft hole 113, whereby the first engagement member 121A is rotated. The joint member 121A may be configured to be movable in the direction of the axis 111x, or the second engagement member 121B is rotatably connected to the positioning member, and the male screw portion of the positioning member May be configured to be movable in the direction of the axis 111x together with the second engagement member 121B by being screwed into the female screw of the shaft hole 113. Further, the first positioning member 125Dp and the second positioning member 125Dq are separately provided as in the above-described end cap 125D, and then connected to the first engagement member 121A as described above. The first positioning member (for example, an end cap) that is screwed into the shaft hole 113 and the second positioning member that is coupled to the second engagement member 121B as described above is the first positioning member. You may comprise so that it may screw with respect to the screw hole provided in this positioning member.

  Furthermore, the first shaft-like member 10 and the second shaft-like member 20 of the above embodiment are not only bone screws (screws) as shown, but also various nails having a shape that can be driven into the bone. It is also possible to use pins. Further, as these nails and pins, those whose diameter is enlarged by various operations from the base end, those in which one or a plurality of tongue-like engagement members protrude in a curved shape (hook pin) from the tip, etc. Various shaft-like members can be used.

DESCRIPTION OF SYMBOLS 10 ... 1st shaft-shaped member (lug screw), 17 ... Longitudinal groove, 18 ... Engagement structure, 20 ... 2nd shaft-shaped member (rotation control pin), 100 ... Intramedullary fixing device, 110 ... Intramedullary nail 111 ... proximal part, 111x ... axis, 112 ... distal part, 112x ... axis, 113 ... axial hole, 114 ... first transverse hole, 114x ... axis, 115 ... second transverse hole (two places), 115x ... axis, 121A, 121A '... first engagement member, 121a, 121a' ... shaft hole, 121p, 121p '... base end, 121g, 121g' ... tip engagement, 121e, 121e '... outer part 121f, 121f '... side opening region, 121s, 121s' ... longitudinal groove, 121B, 121B' ... second engaging member, 121j, 121j '... shaft hole, 121k, 121k' ... tip engaging portion, 121t 121t '... slits, 21u, 121u ', 121v, 121v' ... contact surface, 121n '... guided portion, 122A, 122B ... elastic member (coil spring), 123 ... holding member, 123a ... opening, 123b ... regulating portion, 124 ... Rotation regulating pin, 125 (125A, 125B, 125C, 125D) ... End cap (positioning member), 125a ... Head, 125c ... Step surface (regulated portion), 125e ... Projection portion, 125f ... Step surface (positioning portion) , 125 g ... tip protrusion (step surface), 125 Dp ... first positioning member, 125 Dq ... second positioning member

Claims (23)

A shaft hole extending in the direction of the axis from the base end, a first cross hole opening in the shaft hole and passing through the axis, and a side closer to the base end than the first cross hole A second transverse hole that is open to the shaft hole and avoids the axis and passes through and passes through the shaft hole, the shafts being provided at positions that are biased on both sides of the axis. An intramedullary nail having a transverse hole and inserted into the bone marrow;
A first shaft-like member that engages with the bone while being inserted through the first transverse hole;
A second shaft-like member that engages with the bone while being inserted into at least one of the pair of second transverse holes;
A first shaft member that is received in the shaft hole and engages with the first shaft member inserted from the shaft hole into the first transverse hole, and is capable of holding the first shaft member. 1 holding mechanism;
The pair of second shaft-shaped members are engaged with the pair of second shaft-shaped members that are received in the shaft holes and inserted from the shaft holes into the pair of second transverse holes, respectively. A second holding mechanism configured to be capable of holding;
An intramedullary fixation device comprising:   The second holding mechanism is arranged so as to be movable in the axial direction inside the shaft hole, and can be simultaneously engaged with the pair of second shaft members inserted through the pair of transverse holes, respectively. 2. The intramedullary fixation device according to claim 1, further comprising: a second engaging member configured as described above; and a positioning member that positions the second engaging member in the shaft hole.   The second engagement member has a pair of abutment surfaces each abutting against the pair of second shaft-shaped members respectively inserted through the pair of second transverse holes, in one direction of the axis. The intramedullary fixation device according to claim 2, wherein the intramedullary fixation device is provided on each of both sides of the axis at the end of the axis.   The second engagement member has a tip engagement portion formed along an axis of the second transverse hole, and the pair of contact surfaces are formed in the second crossing at the tip engagement portion. The second shaft-shaped member inserted through the hole has a surface shape that constitutes an extended contact area along the axis of the second shaft-shaped member. Intramedullary fixation device.   The pair of contact surfaces are in contact with the second shaft-shaped member inserted into the second transverse hole at the tip engaging portion so as to be in close contact with the outer peripheral surface of the second shaft-shaped member. 5. The intramedullary fixation device according to claim 3, wherein the intramedullary fixation device has a surface shape that forms an abutting region.   6. The second engaging member has an elastic deformation structure that is configured so that a distance between a portion positioned by the positioning member and the pair of contact surfaces can be expanded and contracted. The intramedullary fixation device according to any one of the above.   The elastic deformation structure increases or decreases a holding force with respect to the second shaft member inserted through the second transverse hole according to a position along a direction of the axis of a portion positioned by the positioning member. The intramedullary fixation device according to claim 6.   The intramedullary bone according to claim 6, wherein the elastic deformation structure gives an equal holding force to the pair of second shaft-shaped members respectively inserted through the pair of second transverse holes. Fixing device.   In the elastic deformation structure, the second shaft-shaped member is inserted into only one of the pair of second transverse holes, and the other second transverse hole is inserted into the second transverse hole. The pith according to claim 6, wherein when the second shaft-shaped member is not inserted, the second shaft-shaped member inserted into any one of the second transverse holes can be held. Internal fixation device.   The said elastic deformation structure is comprised by providing the slit extended helically around an axis line in the side wall of the said 2nd engagement member, The structure of any one of Claim 6 thru | or 9 characterized by the above-mentioned. Intramedullary fixation device.   The second engagement member includes a guided portion that is guided to be movable only in the direction along the axis at a position on the pair of contact surfaces with respect to the elastic deformation structure. The intramedullary fixation device according to claim 6, wherein the device is an intramedullary fixation device. The second engagement member is disposed inside the first engagement member constituting the first holding mechanism,
The first engagement member is provided in an inner housing portion that houses the second engagement member, a concave outer shape portion that avoids the pair of second transverse holes, and the concave outer shape portion, A pair of side opening regions that allow the internal housing portion and the pair of second transverse holes to communicate with each other;
3. The intramedullary fixation device according to claim 2, wherein the pair of contact surfaces of the second engagement member respectively face the pair of second transverse holes through the pair of side opening regions. .   The second engagement member has a guided portion guided by the first engagement member so that the pair of contact surfaces can move only in a direction along the axis. The intramedullary fixation device according to claim 12.   The positioning member is disposed closer to the proximal end than the second engagement member in the shaft hole, and the second engagement when the positioning member is disposed at a predetermined positioning position with respect to the intramedullary nail. The intramedullary fixation device according to claim 2, wherein a member is engaged with the second shaft-like member inserted through the second transverse hole.   The positioning member abuts against a regulated portion whose position is regulated by abutting a predetermined regulating portion provided in the shaft hole of the intramedullary nail and a second engaging member for positioning. The intramedullary fixation device according to claim 14, further comprising a positioning abutment portion for performing the operation.   The positioning member includes a first positioning contact portion for contacting and positioning with the first engagement member, and a second positioning contact for positioning with contact with the second engagement member. The intramedullary fixation device according to claim 15, further comprising a portion.   The medulla according to claim 16, wherein the positioning member has an elastically deformable structure that can extend and contract a distance between the first positioning abutting portion and the second positioning abutting portion. Internal fixation device.   The said 2nd engaging member is supported by the said 1st engaging member via the 2nd biasing means biased to the said base end part side. Intramedullary fixation device.   19. The intramedullary nail according to claim 18, wherein the first engagement member is supported by the intramedullary nail body through first biasing means biasing toward the proximal end side. Fixing device.   The second engaging member and the positioning member are configured separately and separable from each other. When the positioning member is not in contact with the second engaging member, the second engaging member is The intramedullary fixation device according to claim 18 or 19, wherein the intramedullary fixation device is arranged at an initial position where the second urging means does not protrude into the second transverse hole.   The first engaging member and the positioning member are configured separately and separable from each other, and when the positioning member is not in contact with the first engaging member, the first engaging member is 21. The intramedullary fixation device according to claim 20, wherein the intramedullary fixation device is disposed at an initial position where the first urging means does not protrude into the first transverse hole.   Of the opening edges of both side openings of the pair of second transverse holes opening on the surface of the intramedullary nail, a surface groove provided in an opening edge portion closer to the outer diameter with respect to the second transverse hole The intramedullary fixation device according to claim 1, comprising:   The intramedullary fixation device according to claim 22, wherein the surface groove extends from the opening edge portion along the axis and reaches the proximal end portion.

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