JP5819997B2 - Osteotomy nail with smooth back end - Google Patents

Description

  The present invention relates to an implant. Specifically, the present invention relates to bone implants such as osteosynthesis nails.

  Implants, specifically bone implants, include portions or sections or ends that are adapted to be initially guided to the body upon implantation. In this specification, such a portion or section or end is expressed as a tip or tip section or tip end. As a result, the opposite portion or section or end of the implant is adapted to be finally guided to the body, the opposite portion or section or end being a tool for inserting the implant into the body. Further configured to engage. In the following, such opposite part or section or end will be expressed as a rear end or rear end section or rear end.

  Bone implants include osteosynthesis pins, nails or screws. The osteosynthesis nail is, for example, an intramedullary nail such as a femur nail, a humeral nail, or a tibial nail. The osteosynthesis screw may be a screw that fixes the fractured piece, or may be a fixation screw that locks the osteosynthesis nail to the bone.

  However, anatomical variations in the bone cause the posterior end of the bone implant to jump above the bone surface. The posterior end of the implant functions as an interconnect towards the target or aiming device. To form a solid fixation, the nail is pegged to the target device post (pillar) for precise alignment, sufficient fixation, and control of the applied force during insertion and removal of the implant. There may be provided a groove for fitting. Patients may complain of pain in this area after surgery, especially when the posterior end of the implant is popping out of the bone. This pain may be caused by a sharp edge at the posterior end of the implant. Such edges cause inflammation and / or damage to the surrounding soft tissue.

U.S. Patent No. 6,053,077 discloses a typical prior art intramedullary nail.
U.S. Patent No. 6,099,056 describes an intramedullary nail for fixing bone portions together. A lag screw extends into the nail through a radial hole. Furthermore, a cap screw may be screwed into the rear end of this nail to hold the lag screw. The lag screw here has a spherical head.

US Patent No. 7,763,022 US Pat. No. 6,443,954

  One aspect of the present invention can be defined as providing an implant that causes little inflammation to the surrounding tissue when implanted.

This is achieved by the subject matter described in the independent claims. Further embodiments are described in the dependent claims.
In general, an implant, specifically an osteosynthesis nail, has a shaft that includes a distal end and a rear end. The rear end portion has an end surface including at least one concave portion and at least one convex portion. The transition between one recess and the adjacent projection is smoothed. The end face is configured to transmit not only a rotational force but also a translational force from the medical instrument to the shaft of the implant when the medical instrument is coupled at the end face to the posterior end of the implant. The medical device may be a target device as shown in US Pat. No. 5,176,681, but has a shape adapted to mate with the end of the nail of the present invention.

  It should be understood that “smooth” refers to a shape that does not have any edge, specifically a shape that does not have any sharp edge. That is, the end surface is formed in a shape that is not interrupted in the middle. A chamfer may be provided at the edge portion between the end surface of the implant and the outer peripheral surface in the circumferential direction, or may be rounded to be smooth. That is, when the soft tissue is in contact with the posterior end of the implant including the end face, it does not form any edge that causes inflammation of the soft tissue.

According to one embodiment, the end face shows a wave shape along the circumference of the shaft, which may be a sine wave shape. The wave shape extends in the direction of the longitudinal axis of the rear end of the nail. The outer periphery at the target end is generally cylindrical.
Note that the wave shape has only one recess and one protrusion, and the end surface may be formed as a sloped or inclined surface with respect to the longitudinal axis of the implant. I want to be.

According to one embodiment, the end surface includes two or more recesses, and the recess includes a protrusion between the two or more recesses.
The following advantages can be realized by an end face having a wave shape.
-Collision of surrounding tissues can be reduced.
A contour may be formed to fit the bone surface.
-The metal may be a plastic material interconnect that allows for smaller dimensions and lower costs, reducing the stress in the area between the implant and the tool.
-The implant and tool can be easily self-aligned during assembly.
-Interconnects including play with precision are possible.

  According to another embodiment, the end surface corresponds to the shape of the outer bone surface at the target implantation site, whereby the end surface of the implant is the bone surrounding the end surface when the implant is inserted into the bone. It may be flush with the outer surface. For example, depending on the target implantation site such as the femoral head, the end surface has a complex wave shape including another concave portion and another convex portion.

  An exemplary bone implant may be an intramedullary nail that includes a through hole for receiving a fixation screw, the through hole extending laterally through the shaft, but the longitudinal axis of the shaft. It is inclined with respect to. The concave portion of the end surface has a deepest point or a lowest point, and the deepest point or the lowest point can be aligned with the axis of the through hole.

  The bone implant may be an osteosynthesis screw. For example, the osteosynthesis screw may be a fixation screw that is received in a lateral through hole in the shaft of the intramedullary nail. The osteosynthesis screw can be inserted at an angle (not perpendicular) to the bone axis, i.e. inserted at least at an angle to the outer surface of the bone, after the osteosynthesis screw The end has an end surface that includes a corrugation or corrugation that corresponds to the shape of the outer surface of the bone at the guide point or region of the screw. Thus, if the bone outer surface is cylindrical, then the screw receiving end has a high point and a low point that coincide with the bone surface.

  According to another embodiment, the implant further comprises a hole formed at least at the rear end, the hole extending in the longitudinal direction of the shaft. The longitudinal bore includes a female screw for removably securing a medical tool such as a drive tool or target device for manipulating the implant during implantation.

  Alternatively, the implant further has a longitudinal hole at the rear end that includes a bayonet coupler mechanism for releasably securing a medical instrument such as a drive tool or target device. Accordingly, one or more grooves may be provided in the inner surface of the longitudinal hole, each groove being configured to receive a pin-shaped structure. It should be understood that the posterior end of the implant may also include a pin-shaped structure that engages within a bayonet groove formed in the medical device. Such a structure is shown in US Pat. No. 7,901,410 and US Pat. No. 8,337,505.

  According to one embodiment, there is provided a system having an implant as described above, wherein a medical device including an implant engagement portion has a contact surface that corresponds to an end surface at the posterior end of the implant. The medical instrument can be a sighting or target device to assist in guiding the fixation screw and / or drive tool for manipulating the implant during implantation.

  According to another embodiment, the system includes an adapter having a first end adapted to couple to an end face at the posterior end of the implant and a second end adapted to couple to a medical device. It further has an element. By using this adapter element, it is possible to use a normal aiming device or drive tool with an implant having a smooth end face.

  It should be noted that, unless otherwise noted, those skilled in the art will consider any combination of features according to another embodiment as disclosed in this application, in addition to any combination of features belonging to one embodiment. It can be inferred from the above and following description.

  These and other objects, features and advantages of the exemplary embodiments of the present invention will become apparent upon understanding the following detailed description of the exemplary embodiments, when considered in conjunction with the appended claims. It will be.

FIG. 5 shows a medical device coupled to the rear end of an osteosynthesis nail. It is sectional drawing of the state combined in FIG. It is a perspective view of the back end part of the nail for osteosynthesis concerning a 1st embodiment. 1 is a perspective view of an intramedullary nail in a femur. FIG. FIG. 6 is a side view of an intramedullary nail in the femur. It is a perspective view of the back end part of the nail for osteosynthesis concerning a 2nd embodiment.

The present invention will now be described in detail by way of example with reference to the accompanying drawings.
It should be noted that the drawings in the drawings are merely schematic and are not to scale. Throughout the drawings, unless otherwise noted, the same reference signs and characters are used to indicate similar features, elements, components, or parts of the illustrated embodiments. Furthermore, while the present invention will be described in detail with reference to the drawings, the description is made in connection with the exemplary embodiments and is not limited to the specific embodiments shown in the drawings, and Defined by the following claims.

  1 and 2 show a rear end portion 10 of a medical device, such as a target device or drive tool, or a joint 30 of an adapter element disposed between the medical device and the implant. Has been. The coupling part 30 includes an implant engaging part 31. The implant engaging portion has an end surface including a wave shape complementary to the wave shape of the end surface at the rear end portion of the implant.

  The coupling portion further has an internal through hole that includes the first hole portion 33 and the second hole portion 35. The first hole has a first diameter, the second hole has a second diameter, and the second diameter is smaller than the first diameter. The transition from the first diameter to the second diameter is formed by the shoulder 34. The axial hole 11 is formed in the rear end 10 of the implant, and this axial hole includes an internal thread.

  As shown in FIG. 2, the coupling portion 30 is firmly connected to the posterior end portion 10 of the implant by a fixing screw 40. The fixing screw 40 includes a screw head 41 and a screw thread 42. The outer diameter of the screw head is fitted to the first diameter of the first hole 33 of the coupling portion, that is, the outer diameter of the screw head is slightly smaller than the first diameter of the first hole 33. The outer diameter of the thread 42 fits into the second diameter of the second hole 35 of the coupling part 30, that is, the outer diameter of the thread 42 is slightly smaller than the second diameter of the second hole 35. Thereby, the fixing screw 40 is received in the bore of the adapter together with the screw head 41 mounted on the shoulder 34.

  The fixing screw has a length such that the fixing screw protrudes from the coupling part 30 and protrudes into the posterior end 10 of the implant, whereby the thread 42 is axial in the posterior end 10. Engage with the threaded portion of the hole 11. With the fixing screw 40, the end surface of the implant engaging portion 31 of the coupling portion 30 and the end surface of the rear end portion 10 of the implant can be pressed together. This allows the coupling, and thus the medical device, to be fitted into the implant in a predetermined orientation and to allow force transmission in both the translational and rotational directions by means of the corrugated end face. Due to the force exerted in the axial direction by the fixing screw, the end faces can slide relative to each other. In such a configuration, an edge portion for force transmission is not necessary.

  FIG. 3 shows a perspective view of the rear end portion 10 of the osteosynthesis nail. Specifically, an embodiment of the end face 20 is shown. The end surface 20 is a ring-shaped surface extending between the inner surface of the axial hole portion 11 and the outer surface 14. In FIG. 3, the end surface 20 includes two recesses or depressions 21 and two protrusions or ridges 22. Each transition portion 23 between the concave portion 21 and the convex portion 22 is smooth. Smooth means that there are no sharp corners. For example, the end surface 20 may be continuously curved. In this embodiment, the recesses differ from one another for each width. It should also be understood that the recesses differ from one another at each depth. The end face 20 is defined by a continuous wave shape (eg, a sine wave) around the rear end of the osteosynthesis nail around the opening of the axial hole 11. The end surface 20 can have three or four convex portions and concave portions. One embodiment of an end face that includes three recesses and projections is shown in FIG. The distance from the convex peak to the concave peak is 2 to 3.8 mm. In designs that include three peaks, the peaks may be 100-130 degrees apart. In a 15.5 mm diameter proximal nail containing three peaks, for example, the peaks are spaced about 16.23 mm (120 °), which is Pi + 15.5 mm / 3.

  As further shown in FIG. 3, the rear end 10 includes a lateral hole 13 that defines an axis. The deepest point of the recess 21 can be aligned with the axis of the lateral hole 13. Thus, the connecting portion 30 has a predetermined orientation with respect to the rear end portion of the osteosynthesis nail. This is particularly relevant when coupling an aiming or target device to an osteosynthesis nail.

  4 and 5 show an embodiment of a femoral intramedullary nail with the implant already implanted from the proximal end of the femur into the medullary channel of the femur, The femoral head is inserted through the lateral hole 13 of the osteosynthesis nail.

  The fixation screw 50 includes a screw portion 51 adapted to be screwed into the bone and a rear end portion 52 for engaging the drive tool. In these embodiments, the rear end 52 has a crown shape that includes a slot. Here, the corresponding drive tool has a structure for engaging the crown to substantially rotate the screw and screw the screw into the bone. It should be understood that the rear end of the fixation screw has a rear end including a smooth end surface, as described herein.

  4 and 5 further, the smooth end face 20 at the rear end 10 of the femoral joint nail substantially corresponds to the bone profile at the guide point of the nail, ie at the greater trochanter of the femur. It is shown to have such a contour.

  Although the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered as examples or illustrations and are not limited to these examples or illustrations. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and realized by those skilled in the art in practicing the claimed invention, from a study of the drawings, the specification disclosure, and the appended claims. .

  In the claims, the word “comprising” does not exclude other elements, and the indefinite article “a (a), (an)” does not exclude a plurality.

  The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the claim.

DESCRIPTION OF SYMBOLS 10 Rear end part of shaft 11 Axial direction hole part including internal thread 12 Axial direction hole part 13 Horizontal hole 14 Outer surface 20 End surface 21 Recessed part 22 Convex part 23 Transition part 30 Joint part 31 Implant engaging part 32 Tool engaging part 33 1st Hole 34 Shoulder 35 Second hole 40 Fixing screw 41 Screw head 42 Screw thread 50 Fixing screw 51 Fixing screw thread 52 Tool engaging part of fixing screw

Claims (13)

An osteosynthesis nail, the osteosynthesis nail is
A tip adapted to be initially guided to the body during implantation of the osteosynthesis nail and after being adapted to be finally guided to the body during implantation of the osteosynthesis nail and an end portion viewed free, has a shaft including a longitudinal axis and a circumferential surface,
The rear end portion terminates at an end surface that intersects the longitudinal axis of the shaft and extends to the peripheral surface of the shaft;
The end surface is shown to be continuously curved with a sinusoidal waveform, and the end surface is recessed with a recess recessed in a direction parallel to the longitudinal axis of the shaft, and a longitudinal axis of the shaft. and Nde including a convex portion that protrudes in a direction parallel against the transition portion between the concave portion and the convex portion is smoothly formed,
Nail for osteosynthesis. Said end face, when the medical instrument is binding to the rear end of the shaft at the end face, it is possible to transmit the rotational force and the translational force to the shaft from the medical device,
The osteosynthesis nail according to claim 1. The end face includes two or more concave portions having a convex portion between two or more concave portions,
The osteosynthesis nail according to claim 1 or 2 . The end surface corresponds to the shape of the outer bone surface at the target implantation site, whereby the end surface of the osteosynthesis nail surrounds the end surface when the osteosynthesis nail is inserted into bone. Be flush with the bone surface,
The osteosynthesis nail according to any one of claims 1 to 3 . The osteosynthesis nail is an intramedullary nail including a through hole (13) for receiving a fixation screw (50), the through hole being in a direction intersecting the longitudinal axis of the shaft. Extending through,
The osteosynthesis nail according to claim 4 . Deepest point before Symbol recesses, aligned with the axis of the through hole (13),
The osteosynthesis nail according to claim 5 . Further comprising an osteosynthesis screw for fixing the osteosynthesis nail when embedded.
The osteosynthesis nail according to claim 3 . Wherein which further comprises an axial bore (11) to the rear end, axial longitudinal bore is of the shaft longitudinal axis for fixing removably provided and medical device extending in a direction parallel against Including female thread,
The osteosynthesis nail according to any one of claims 1 to 7 . Wherein which further comprises an axial bore (11) to the rear end, axial longitudinal bore is of the shaft longitudinal axis for fixing removably provided and medical device extending in a direction parallel against Including the mechanism of the bayonet coupler,
The osteosynthesis nail according to any one of claims 1 to 7 . A medical device, the medical device having an implant engaging portion including a contact surface having a corrugation corresponding to the corrugation of the end surface at the rear end of the osteosynthesis nail;
The osteosynthesis nail according to any one of claims 1 to 9 . The medical device is a target device that assists in guiding a fixing screw and / or a driving tool for operating the osteosynthesis nail when the osteosynthesis nail is implanted.
The osteosynthesis nail according to claim 10 . A first end (31) adapted to couple to the end face (20) at a rear end (10) of the osteosynthesis nail and a second end adapted to couple to a medical device; Further comprising an adapter element comprising:
The osteosynthesis nail according to any one of claims 1 to 10 . The rear end of the nail comprises a three projections and three recesses, such as to have a peak-to-peak amplitude between 2.5～3.8Mm,
The osteosynthesis nail according to any one of claims 1 to 12 .

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