Intramedullary nail for long bone traction

Abstract

An intramedullary nail (1) for long bone traction comprises a first tube (3) extending along the axial direction of the intramedullary nail (1); a second tube (5) extending along the axial direction of the intramedullary nail (1), the second tube (5) being coupled to the first tube (3) so as to be axially movable with respect to each other; a first locking opening (7) located in the end region of the first tube (3) away from the second tube (5); and a coil (11) arranged in the coil region of the first tube (3) between the first locking opening (7) and the second tube (5).

Description

Technical Field

[0001] The invention relates to an intramedullary nail for long bone traction. Prior art

[0002] Intramedullary nail is known in the prior art and can pull rectangular long bones. Two bone pieces (that is, the first bone piece and the second bone piece) move relative to each other through the intramedullary nail. Bone can grow again at the contact point between the two bone pieces. To achieve this, a sufficiently low feed rate can be selected for the driver of the traction intramedullary nail. It is known to supply the required energy of the driver to the intramedullary nail in a percutaneous manner. From EP 1 033 112 B1, it is known that a receiving antenna is arranged in the housing of the intramedullary nail or on the front side of the housing outside of the intramedullary nail.

[0003] However, the solutions known so far from the prior art have limitations in terms of energy transmission performance or energy transmission efficiency, require more space or require coupling of the intramedullary nail with a receiving antenna arranged outside the intramedullary nail. Summary of the invention

[0004] The object of the present invention is to provide an intramedullary nail which is improved over the prior art. In particular, the intramedullary nail should be able to achieve high energy transmission performance, should have high energy transmission efficiency, should occupy a small bone space or should be able to be implanted near a joint. In addition, it is also desired that the intramedullary nail requires as little surgical intervention as possible or can be reliably fixed in a bone fragment.

[0005] According to one aspect of the present invention, there is provided an intramedullary nail for long bone traction, which comprises a first tube extending along the axial direction of the intramedullary nail; a second tube extending along the axial direction of the intramedullary nail, the second tube being coupled to the first tube so as to be axially movable with respect to each other; a first locking opening located in an end region of the first tube away from the second tube; and a coil arranged in a coil region of the first tube between the first locking opening and the second tube.

[0006] Another aspect of the invention relates to a method for transmitting energy from a primary coil to a coil of an intramedullary nail in one of the typical embodiments described herein, comprising energizing the primary coil and receiving, by the coil of the intramedullary nail, at least a portion of the electromagnetic energy emitted by energizing the primary coil.

[0007] Exemplary intramedullary nails are particularly suitable for treating rectangular long bone fractures or other injuries, wherein other injuries can be bone defects caused by, for example, tumors or violent impacts. The bones that can be treated with typical intramedullary nails are thigh bones (femurs) and tibias, but upper arm bones (humeri), ulna, radius and fibula can also be treated.

[0008] In a typical embodiment, the second tube can move axially in the first tube. In a further typical embodiment, the first tube can move axially in the second tube. Generally, the terms "axial" and "radial" in this article should be understood relative to the longitudinal axis of the intramedullary nail, wherein the longitudinal axis specifically extends along the intramedullary nail or the maximum expansion space of the intramedullary nail. In particular, the axial direction should be understood as the direction along the longitudinal axis of the intramedullary nail or parallel to the longitudinal axis of the intramedullary nail, and the radial direction should be understood as the direction perpendicular to the longitudinal axis. The longitudinal axis of the intramedullary nail can also be curved, for example, in an intramedullary nail with a continuous bend for lower limbs according to Herzog. Typically, the intramedullary nail is at least substantially circular in a cross section relative to the longitudinal axis of the intramedullary nail.

[0009] In a typical embodiment, the coil is implemented as a receiving coil or a secondary coil. Typically, the coil is arranged to receive energy from a primary coil arranged outside the body, in particular for operating a driver of an intramedullary nail. Typically, the primary coil is implemented as a toroidal coil or a saddle coil. Typically, the coil is assigned to the first tube. Typically, the coil is arranged in or at the first tube.

[0010] In a typical embodiment, the intramedullary nail and the primary coil are arranged for percutaneous data transmission between the coil and the primary coil. Typically, the intramedullary nail comprises a data processing unit for sending data via the coil or for reading data received via the coil.

[0011] Typical embodiments have a locking opening, specifically, a first locking opening in the first tube end region. Usually, the locking opening is arranged to insert or pass a locking device, which is used to lock the intramedullary nail in the bone fragment of the long bone, specifically, in the first bone fragment or the second bone fragment. Like this, the intramedullary nail can be connected to the bone fragment of the long bone, so that it is fixed in all directions and all rotational directions. Therefore, the intramedullary nail can be fixedly connected to the bone fragment in all degrees of freedom. Specifically, a bolt or a screw can be used as a locking device. Screws or bolts enable the intramedullary nail to be fixed in the bone fragment.

[0012] In a typical embodiment, the locking opening is oriented at a fixed angle. The advantage of the fixed angle orientation is that two or more locking openings or locking devices can be tightened relative to each other. Typically, the locking opening passes through the intramedullary nail radially. In a further typical embodiment, the locking opening forms a certain angle with the longitudinal axis of the intramedullary nail, and the angle is specifically less than 110° or less than 100°. In a typical embodiment, the angle is greater than 70°, for example greater than 80°. Typically, two or more locking openings are oriented parallel to each other. In a further typical embodiment, two or more locking openings are oriented to twist relative to each other. Specifically, the locking openings twist at most 7°, for example at most 5° relative to each other. Typically, the locking openings are oriented to intersect or deflect relative to each other.

[0013] In a typical embodiment, the first tube is made of at least two interconnected pipe fittings. Typically, the pipe fittings are interconnected, welded together, bonded together, or connected using a connection process. Typically, the pipe fittings include an end piece located in the end region of the first tube, a mandrel located in the coil region, a hollow piece located at the end of the first tube opposite to the end region, or an intermediate piece located in the middle region between the mandrel and the hollow piece. In this article, specifically, the pipe fitting should not be understood as being limited to the region of the first tube, and in a typical embodiment, it also extends to other regions of the first tube. For example, the mandrel can extend into the end region, specifically, a locking opening can be included. In addition, two or more pipe fittings (e.g., a mandrel and an intermediate piece) can be made into one piece.

[0014] Typically, in particular, the first tube and the second tube consist essentially of a metal or a metal alloy, in particular a biocompatible metal or a biocompatible metal alloy.

[0015] In typical embodiments, at least one hollow part of the first tube consists essentially of metal or a metal alloy, in particular, a biocompatible metal or a biocompatible metal alloy. In an embodiment, the hollow part, the middle part, the end part or the mandrel of the first tube consists essentially of metal or a metal alloy, in particular, a biocompatible metal or a biocompatible metal alloy. In typical embodiments, the end part, the mandrel or the middle part consists at least essentially of a plastic, such as an epoxy resin, a silicone resin or a thermoplastic resin. Typically, the metal tube is coupled to another plastic tube by a closure.

[0016] In an exemplary embodiment, the mandrel is welded or bonded to the end piece, overmolded with the end piece, or otherwise coupled to the end piece.

[0017] In a typical embodiment, the first tube has a smaller outer diameter in the coil region. For example, "having a smaller outer diameter" may mean that there is a cross-sectional narrowing or a gradual narrowing of the cross section. In the coil region, the coil is usually arranged radially outside the first tube. Typically, the coil surrounds the first tube. Typically, the coil is realized to be axially symmetrical.

[0018] In this context, the outer diameter of the intramedullary nail, tube or coil envelope is understood to be the outer diameter of the intramedullary nail, tube or coil envelope in a cross section relative to the longitudinal axis of the intramedullary nail.

[0019] In a typical embodiment, the coil is a cylindrical coil and is arranged coaxially with the intramedullary nail. In a further typical embodiment, the coil is implemented as a planar coil array, specifically, as an axially symmetrical planar coil array, or with a saddle coil as the primary coil. In a further typical embodiment, the coil is implemented as a toroidal coil or a saddle coil.

[0020] Typically, the coil has a coil length in the axial direction corresponding to at least 0.8 times (specifically, at least 1 times) the outer diameter of the intramedullary nail, or a coil length corresponding to at least 2.5 times the outer diameter of the intramedullary nail. For example, the number of windings of the coil can be adjusted according to the outer diameter of the mandrel or the coil length.

[0021] In a typical embodiment, a coil envelope (particularly a coaxial coil envelope) surrounds the coil, wherein the coil envelope is at least substantially composed of a non-metallic material. Typically, the coil envelope is made of at least 70%, particularly at least 80% or at least 90% non-metallic material. Typically, the non-metallic material comprises plastics, such as epoxy, silicone or thermoplastic resins or ceramics or glass. Typically, the plastic material used to make the coil envelope is biocompatible. Typically, the coil envelope is made in the following manner, i.e., the coil is overmolded or overcasted using a plastic material. For example, it may be advantageous to make it by overcasting because there will be no mechanical forces for fixing the coil to be overcasted or one or more pipes to be overcasted.

[0022] In a typical embodiment, the coil envelope is made by over-casting or over-molding the coil arranged at the first tube with a plastic material. In an exemplary embodiment, the coil envelope is made by over-molding the coil in an injection mold. In a further typical embodiment, the coil envelope is made by over-molding the coil arranged at the tube of the first tube of a multi-piece realization with a plastic material, wherein the over-molding is performed before the tube of the first tube is joined.

[0023] Typically, the coil envelope is at least substantially transparent to alternating electromagnetic fields, in particular to alternating electromagnetic fields having a frequency of at least 1 kHz (e.g. at least 10 kHz or at least 100 kHz) or at most 1 GHz (e.g. at most 100 MHz or at most 10 MHz).

[0024] In an exemplary embodiment, the coil envelope at least substantially radially fills the coil area to the outside in a manner flush with the outer profile of the first tube. In an exemplary embodiment, the coil envelope is oriented coaxially with the coil or coaxially with the longitudinal axis of the intramedullary nail. Typically, the coil envelope surrounds the coil or the first tube (particularly, in the coil area) in an annular manner.

[0025] In a typical embodiment, the first tube includes a coil core radially arranged inside the coil. Typically, the coil core is a ferrite core. Typically, the coil core is hollow. Typically, the coil is arranged at the coil core. Typically, the coil core and the coil are encapsulated by a plastic material, such as epoxy resin. Typically, the coil core is coaxially arranged with the intramedullary nail.

[0026] In a typical embodiment, the coil core has an axial protrusion at the axial end of the coil. Typically, the coil core has radial protrusions at both axial ends. Typically, the radial protrusions are adapted to shield the winding of the core from the metal tube. Typically, the radial protrusions form radial stops for the coil winding.

[0027] Typically, the first tube is realized to be at least substantially full in the coil region or in the portion with the smaller outer diameter. Specifically, the cross section of the first tube in the coil region is at least 30% full, for example at least 50% full, at least 70% full or at least 90% full. In a typical embodiment, the first tube in the coil region is formed by a mandrel realized as a complete cylinder.

[0028] In a typical embodiment, the first tube has a second locking opening in the middle region between the coil region and the second tube. Typically, the second locking opening is realized in the middle part of the first tube, wherein the intermediate piece is arranged axially on the side of the coil region facing the second tube, in particular, in the middle region between the mandrel and the hollow piece of the first tube.

[0029] In typical embodiments, the distance between the first locking opening and the second locking opening is at most 30 mm, in particular at most 25 mm.

[0030] Typically, the intramedullary nail comprises a driver electrically connected to the coil. Typically, the driver is arranged in the first tube between the coil area and the second tube, specifically, between the intermediate piece and the second tube. Typically, the electrical connection between the coil and the driver is achieved by a feedthrough, specifically, by an intermediate piece. For example, the feedthrough is achieved in the axial direction. Typically, the feedthrough is achieved by drilling. In a typical embodiment, the driver comprises a motor (specifically, an electric motor). Typically, the driver comprises a gear (e.g., a multi-stage planetary gear). In a typical embodiment, the driver comprises an electronic system or a sensor system for controlling and monitoring the driver. Typically, the driver comprises an electrical energy storage device.

[0031] In a typical embodiment, the outer diameter of the first tube in the coil region, in particular the outer diameter of the central axis of the coil region, is greater than the diameter of the first locking opening or greater than the diameter of the second locking opening. Typically, the outer diameter of the mandrel of the first tube in the coil region is greater than the diameter of the first locking opening or greater than the diameter of the second locking opening. Typically, the outer diameter of the mandrel of the first tube in the coil region is at least 2 mm, in particular, at least 4 mm or at least 6 mm. The outer diameter of the mandrel of the first tube in the coil region is at least 1 mm, in particular at least 1.5 mm or at least 2 mm, less than the outer diameter of the coil envelope.

[0032] In a typical embodiment, the mandrel of the first tube has a radial fillet axially facing the middle piece of the first tube. The radial fillet facilitates the transfer of mechanical bending loads between the mandrel and the middle piece. Typically, the coil core arranged on the mandrel has a groove matching the radial fillet. Typically, the mandrel and the middle piece are made in one piece.

[0033] In a typical embodiment, the intermediate piece of the first tube has an axial protrusion axially in the direction of the second tube, which axial protrusion is suitable for interlocking the intermediate piece with the hollow piece of the first tube. In a further typical embodiment, the intermediate piece and the hollow piece are welded together.

[0034] In typical embodiments, the first tube has a third locking opening in an intermediate region between the first locking opening and the coil region or between the coil region and the hollow part of the first tube.

[0035] Typically, the second tube has a further locking opening, in particular at the end of the second tube opposite the first tube.

[0036] In a typical embodiment for transferring energy from a primary coil to a coil of an intramedullary nail, in particular, the primary coil is arranged around the coil of the intramedullary nail or near the coil of the intramedullary nail, in particular, on the skin of a patient or a treatment animal. Typically, when the primary coil is energized, a voltage (in particular, an alternating voltage) is applied to the primary coil, and a first current (in particular, an alternating current) flows through the primary coil. The energized primary coil generally generates an alternating magnetic field. Typically, energy is received by the coil of the intramedullary nail, wherein a second current is induced in the coil of the intramedullary nail by the alternating magnetic field. The energy transferred from the primary coil to the coil of the intramedullary nail (in particular, in the form of pulses generated by the primary coil) can be used, for example, to drive the gears of the intramedullary nail (in particular, to drive the gears of the intramedullary nail in real time) so as to power the electronic system of the intramedullary nail or to charge the electric energy storage of the intramedullary nail.

[0037] Typical advantages of embodiments include, for example, that the intramedullary nail requires less space. Typical intramedullary nails can also be implanted at low osteotomy heights or close to joints. A further advantage is that the intramedullary nail can ensure high energy transfer performance or have high energy transfer efficiency. Typical intramedullary nails can ensure more targeted control, can have higher reliability, or can provide higher traction. Another advantage is that no feeder is required between the coil arranged outside the intramedullary nail and the intramedullary nail. The intramedullary nail of typical embodiments can shorten and simplify the time and procedure of intramedullary nail implantation or removal surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Hereinafter, exemplary embodiments of the present invention are explained in more detail according to the accompanying drawings. As shown below:

[0039] Figure 1A schematic overview of an intramedullary nail for long bone distraction is shown;

[0040] Figure 2 shows a schematic cross-sectional view of an intramedullary nail;

[0041] Figure 3 a schematic cross-sectional view showing details of another embodiment of an intramedullary nail;

[0042] Figure 4A a schematic cross-sectional view showing a detail of an intramedullary nail having a third locking opening;

[0043] Figure 4B a schematic cross-sectional view showing a detail of an intramedullary nail without any locking openings in the middle piece of the first tube;

[0044] Figure 5A A schematic cross-sectional view showing a detail of an intramedullary nail, wherein the first locking opening and the second locking opening are twisted relative to each other;

[0045] Figure 5B A schematic cross-sectional view showing a detail of an intramedullary nail, wherein the first locking opening and the second locking opening are oriented obliquely with respect to the longitudinal axis of the intramedullary nail;

[0046] Figure 6 A schematic cross-sectional view showing a detail of an intramedullary nail having a multi-component end piece;

[0047] Figure 7 A schematic cross-sectional view of a detail of an intramedullary nail is shown, wherein the mandrel of the first tube has a radial fillet towards the intermediate piece. DETAILED DESCRIPTION

[0048] In the following, typical embodiments of the present invention will be described, wherein the same reference numerals will be used for the same or similar components and explanations may not be repeated for each figure. The present invention is not limited to the typical embodiments described below. For the sake of clarity, not all corresponding features have reference numerals, especially when features are assigned once or more to elements surrounding the longitudinal axis of the intramedullary nail, e.g. Figure 2 The coil core is denoted by reference numeral 27 .

[0049] Figure 1 A schematic overview of an intramedullary nail 1 for distracting a long bone of a patient 51 is shown. The intramedullary nail 1 is arranged in the long bone, wherein a first tube 3 of the intramedullary nail 1 is locked with a first bone fragment 53 and a second tube 5 is locked with a second bone fragment 55. The second tube 5 is connected to the first tube 3 so as to be axially movable relative to each other. Figure 1 In the embodiment, the second tube 5 is partially introduced into the first tube 3 and can move axially relative to the first tube 3.

[0050] exist Figure 1In the embodiment, the first tube 3 has a first locking opening 7 in the end region at the end of the first tube 3 opposite to the second tube 5. The first locking device 9 is Figure 1 In the middle is a screw which is introduced into the first bone fragment 43 and positioned through the first locking opening 7 .

[0051] The coil 11 is arranged at the first tube 3 in the coil region between the first locking opening 7 and the second tube 5. In the coil region, the first tube 3 has a smaller diameter, in particular compared to the outer diameter of the first tube 3 in the adjacent end region or in the middle region, which is axially adjacent to the coil region in the direction of the second tube 5. In the coil region, the coil 11 is surrounded by a coil envelope 13. Figure 1 In the embodiment, the coil envelope 13 fills the coil area radially to the outside so as to be flush with the outer diameter of the first tube 3 in the end area and flush with the outer diameter of the first tube 3 in the middle area.

[0052] exist Figure 1 In the embodiment, the coil 11 is implemented as a cylindrical coil. For example, Figure 1 The primary coil 59 of the annular coil in the embodiment is arranged on the patient 51 in vitro, specifically, around the coil 11. The primary coil 59 is adapted to provide an alternating magnetic field so that energy is inductively transferred to the intramedullary nail 1, specifically, to the coil 11, by an alternating magnetic field induction current in the coil 11.

[0053] The second locking opening 15 is arranged in the middle region between the coil region and the second tube 5. The second locking device 17 is introduced into the first bone fragment 53 and positioned through the second locking opening 15.

[0054] exist Figure 1 In the embodiment, the driver is arranged between the second tube 5 and the coil 11, for example, between the second tube 5 and the second locking opening 15. Figure 1 In the embodiment, the drive is a motor 19 (particularly an electric motor). Typically, the drive and the gear 21 are adapted to move the first tube 3 and the second tube 5 axially relative to each other. In order to distract the long bone, the second tube 5 is slowly moved out. Figure 1 The first tube 3 in the long bone is separated from the first bone fragment 53 and the second bone fragment 55, and the long bone is extended. In this case, new bone tissue may grow in the ossification zone 57. Figure 1 In the embodiment, energy is supplied to the driver through coil 11.

[0055] In the second tube, another locking opening 23 is arranged at the end of the second tube 5 opposite to the first tube 3. Another locking device 25 is introduced into the second bone fragment 55 and positioned through the other locking opening 23. The other locking device 25 locks the second bone fragment 55 to the second tube 5 through the other locking opening 23. For greater clarity, the locking device is not shown in the further figures.

[0056] Figure 2 A schematic side view of an intramedullary nail 1 having a first tube 3 and a second tube 5 is shown, which are arranged along the longitudinal axis 2 of the intramedullary nail 1. The second tube 5 is partially arranged in the first tube 3 and can be axially moved relative to the first tube 3. The second tube 5, the motor 19 and the gear 21 are arranged in a hollow part 41 of the first tube 3. An end piece 47 of the first tube 3 is arranged in the end area of ​​the first tube 3 opposite to the second tube 5. The end piece 47 surrounds the mandrel 45 of the first tube 3, which protrudes into the end area from the coil area of ​​the first tube 3 adjacent to the end area. The first locking opening 7 extends through a metal sleeve 8. The metal sleeve 8 passes through the mandrel opening of the mandrel 45 and the end piece opening of the end piece 47. The mandrel opening of the mandrel 45 and the end piece opening of the end piece 47 are arranged to be aligned with each other. The metal sleeve 8 is welded to the end piece 47 along the circumference of the end piece opening.

[0057] In further exemplary embodiments, the mandrel is directly welded, bonded, or otherwise connected to the end piece.

[0058] In the coil region, the first tube 3 comprises a mandrel 45 and a coil core 27 arranged radially on the outside around the mandrel 45. The mandrel 45 has a smaller outer diameter than an end piece 47 or an intermediate piece 43 adjacent to the shaft 45, which is arranged between the coil region and the hollow piece 41. Figure 2 In the embodiment, the mandrel 45 and the intermediate member 43 are made of metal. The mandrel 45 and the intermediate member 43 are made in one piece.

[0059] exist Figure 2 In the embodiment, the coil core 27 is implemented as a ferrite core. The coil core 25 has radial protrusions 29 in the axial direction of the end piece 47 and the intermediate piece 43. The coil 11 is arranged radially on the outside of the coil core 27 and surrounds the coil core 27. Figure 2 In the embodiment, the coil 11 is realized as a cylindrical coil. The coil 11 is arranged between radial protrusions 29 of the coil core 27 .

[0060] The radial protrusion 29 of the coil core 27 is particularly advantageous when the adjacent pipes such as the intermediate piece 43 or the end piece 47 are made of metal. The coil core 27 can shield the coil 11, specifically, the winding of the coil 11, or the magnetic flux passing through the coil core 27 from the adjacent pipes.

[0061] The coil core 27 and the coil 11 are surrounded by a coil envelope 13 facing radially outward. The coil envelope 13 is produced by casting the coil region of the first tube 3 with plastic material.

[0062] exist Figure 2, the intermediate piece 43 has a second locking opening 15. The intermediate piece 43 comprises an axial protrusion towards the second tube 5, which interlocks with the hollow piece 41. The hollow piece 41 is radially welded to the intermediate piece 43. The intermediate piece 43 has an axial hole, through which the electrical connection between the coil 11 and the motor 19 is guided. In a further exemplary embodiment, the axial hole is realized as a partial or complete winding.

[0063] Figure 3 Detail of another embodiment of the intramedullary nail 1 is shown. Figure 3 In the embodiment of the present invention, the mandrel 45 of the first tube 3 is welded to the end piece 47 of the first tube 3 and does not at least substantially protrude into the end piece 47. Typically, the mandrel 45 is welded to the end piece 47 at the front side. The first locking opening 7 does not pass through the mandrel 45. The intermediate piece 43 is formed integrally with the mandrel 45.

[0064] exist Figure 4A In the embodiment, the first tube of the intramedullary nail 1 has, in addition to the first locking opening 7 in the end region of the first tube 3 and the second locking opening 15 in the middle piece 43 of the first tube, a third locking opening 31 between the first locking opening 7 and the coil region.

[0065] Figure 4B Shows something like Figure 4A , but without the second locking opening 15 in the intermediate piece 43. Figure 4A and Figure 4B In the embodiment, the first locking opening 7 and the third locking opening 31 pass through the end piece 47 and the spindle 45. In a further embodiment, Figure 3 Similarly, the spindle 45 may protrude shorter or not at all into the end piece 47 , and the first locking opening 7 or the third locking opening 31 may not be realized by the spindle 45 .

[0066] Figure 5A and Figure 5B An intramedullary nail 1 is shown which has locking openings which are twisted relative to one another or which are oriented obliquely relative to the longitudinal axis 2 of the intramedullary nail 1. Figure 5A In the embodiment, the first locking opening 7 and the second locking opening 15 are oriented in different radial directions. Figure 5B In the embodiment, the first locking opening 7 and the second locking opening 15 are oriented obliquely relative to the longitudinal axis 2 of the intramedullary nail 1. Figure 5B In the embodiment shown in FIG. 1 , the first locking opening 7 and the second locking opening 15 are oriented toward a common intersection point.

[0067] Figure 6 Another embodiment of an intramedullary nail 1 having a multi-part end piece 47 is shown. The end piece 47 comprises a first end piece 33, a second end piece 35 and a threaded insert 37. Figure 6In the embodiment, the first end piece 33 is realized as a metal sleeve. The first end piece 33 passes through the spindle opening 46 of the spindle 45. The first locking opening 7 passes through the end piece 33. Figure 6 In the embodiment, the first locking opening 7 and the second locking opening 15 are Figure 6 The mandrel 45 surrounds the first end piece 33 and protrudes into the second end piece 35. The middle piece 43 is made in one piece with the mandrel 45. The coil envelope 13 and the second end piece 35 are made by overmolding the middle piece 43 in an injection mold using a biocompatible plastic material, specifically, along the axial portion of the middle piece 43, the mandrel 45, the coil core 27, the coil 11, the first end piece 33 and the threaded insert 37.

[0068] In a further exemplary embodiment, there is no threaded insert. In such exemplary embodiments, the threaded insert is subsequently introduced into the plastic material, in particular, is introduced in a screwed manner.

[0069] exist Figure 6 In the embodiment, the middle piece 43 of the first piece has a radial groove 44 facing the coil area. The coil envelope 13 extends axially into the radial groove 44. In the radial groove, the first tube and the coil envelope 13 are connected in a form-fitting manner.

[0070] Figure 7 A schematic cross-sectional view of an intramedullary nail 1 is shown with a mandrel 45 having a radial fillet 39 facing the intermediate piece 43. The radial fillet 39 can be advantageous for improving the transmission of bending loads between the mandrel 45 and the intermediate piece 43, in particular, for improving the transmission of bending loads between the first locking opening (not shown) and the second locking opening 15. The coil core 27 has a groove matching the fillet 39 axially in the direction of the intermediate piece 43. The radial fillet 39, in particular, the radial fillet with matching grooves in the coil core 27 is not limited to Figure 7 An exemplary embodiment of the present invention may also be Figures 1 to 6 is implemented in an exemplary embodiment of .

[0071] The invention is not limited to the exemplary embodiments described above. The scope of the invention is determined by the claims. In particular, not all parts shown must be features of the invention, which applies in particular to the human bones shown.

Claims

1. An intramedullary nail for long bone traction (1), comprising - a first tube (3) extending along the axial direction of the intramedullary nail (1); - a second tube (5) extending in the axial direction of the intramedullary nail (1), the second tube (5) being coupled to the first tube (3) so as to be axially movable with respect to each other; - a first locking opening (7) for locking the intramedullary nail in the bone fragment of the long bone, located in the end region of the first tube (3) remote from the second tube (5); - a coil (11) arranged in the coil region of the first tube (3) between the first locking opening (7) and the second tube (5); - a driver, electrically connected to the coil (11), - wherein the first tube (3) extends axially uninterruptedly between the first locking opening (7) and the second tube (5); wherein the first tube (3) has a smaller outer diameter in the coil region, and the coil (11) is wound around the smaller outer diameter of the first tube (3).

2. The intramedullary nail (1) according to claim 1, wherein a coil envelope (13) surrounds the coil (11), and wherein the coil envelope (13) is composed of a non-metallic material.

3. The intramedullary nail (1) according to claim 2, wherein the coil envelope (13) is made by overcasting or overmolding the coil (11) arranged on the first tube (3) with a plastic material.

4. The intramedullary nail (1) according to claim 2 or 3, wherein the coil envelope (13) radially fills the coil area to the outside in a manner flush with the outer contour of the first tube (3).

5. The intramedullary nail (1) according to claim 1, wherein the coil (11) is a cylindrical coil and is arranged coaxially with the intramedullary nail (1).

6. The intramedullary nail (1) according to claim 1, wherein the first tube (3) comprises a coil core (27) arranged radially inside the coil (11).

7. The intramedullary nail (1) according to claim 6, wherein the coil core (27) has a radial protrusion (29) at an axial end of the coil (11).

8. The intramedullary nail (1) according to claim 1, wherein the first tube (3) is made of at least two interconnected tubes.

9. The intramedullary nail (1) according to claim 1, wherein the first tube (3) is embodied filled in the coil region.

10. The intramedullary nail (1) according to claim 1, wherein the first tube (3) has a second locking opening (15) in a middle area between the coil area and the second tube (5).

11. The intramedullary nail (1) according to claim 10, wherein the distance between the first locking opening (7) and the second locking opening (15) is at most 30 mm.

12. The intramedullary nail (1) according to claim 10, wherein the smaller outer diameter of the first tube (3) in the coil region is greater than the diameter of the first locking opening (7) and / or greater than the diameter of the second locking opening (15).

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