WO2022047514A1

WO2022047514A1 - Implant for fixing a first bone part and a second bone part of a fractured bone

Info

Publication number: WO2022047514A1
Application number: PCT/AT2021/060311
Authority: WO
Inventors: Johann Scheicher
Original assignee: V.I.E.-Systems Gmbh
Priority date: 2020-09-07
Filing date: 2021-09-06
Publication date: 2022-03-10
Also published as: AT524172A1

Abstract

The invention relates to an implant (1) for fixing a first bone part (2) and a second bone part (3) of a fractured bone, having: - a first fastening element (4) for fastening in the first bone part (2); - a second fastening element (5) for fastening in the second bone part (3); - a connecting element (6) for connecting to the first fastening element (4) and to the second fastening element (5), wherein the connecting element (6) and the first fastening element (4) have first interacting connecting devices (7) and the connecting element (6) and the second fastening element (5) have second interacting connecting devices (8), such that a distance between the first fastening element (4) and the second fastening element (5) can be changed; characterized in that the first fastening element (4), the second fastening element (5) and the connecting element (6) have a bioresorbable material.

Description

Implant for fixation of a first bone part and a second bone part of a fractured bone

The invention relates to an implant for fixing a first bone part and a second bone part of a broken bone, comprising:

- a first fastening element for fastening in the first bone part;

- a second fastening element for fastening in the second bone part;

- a connecting element for connection to the first fastening element and to the second fastening element, wherein the connecting element and the first fastening element have first cooperating connecting devices and the connecting element and the second fastening element have second cooperating connecting devices, so that a relative distance between the first fastening element and the second fastening element to one another can be changed .

In addition to plate osteosynthesis, it is known to treat bone fractures with locking intramedullary nails. To do this, the nail is inserted into the marrow cavity over the entire length of the bone and fixed using several locking bolts inserted transversely proximally and distally. For example, these nails are made of solid titanium alloys.

Furthermore, US Pat. No. 5,334,184 A shows a device for internally fixing two parts of a fractured tubular bone. With the device, however, the bone parts cannot be pulled close to one another, but a distance remains between the parts. Therefore, over the long term, the device must replace part of the bone and not degrade. It is known, however, that bone degradation takes place disadvantageously due to the permanent relief of the bone in the case of marrow nails and in the case of devices such as those shown in US Pat. No. 5,334,184 A.

US Pat. No. 4,016,874 A shows a similar device for implanting two parts of a fractured long bone in the marrow cavity Material must be made so that they do not have to be removed later. However, this results in the same disadvantages as explained above in connection with US Pat. No. 5,334,184 A. In addition, the bone parts can be set up less precisely, since the central rod is only fixed with one of the two outer parts and thus a relative movement of the bone parts to one another is not blocked or prevented by the device. the relative position of the bone parts to each other is not fixed.

In addition, medullary lengthening nails for leg lengthening are known. The lengthening takes place, for example, by means of a built-in motor or mechanically by means of a ratchet mechanism. All of these systems are removed after lengthening has been achieved and bony healing, again with the problem of bone loss. On the other hand, because of the necessary removal, another operation with the associated disadvantages is necessary.

It is an object of the present invention to alleviate or eliminate at least one disadvantage of the prior art. In particular, it is an object of the invention to propose an implant for fixing a first bone part and a second bone part of a broken bone, with which an improved and/or simplified treatment of the broken bone is possible. In particular, a stable fixation of the bone parts belonging to one another and a connection of the bone parts with one another in the correct or corrected position can be achieved. Furthermore, in particular, the need for a further operation and the bone resorption that sets in with permanent relief of the bone should be avoided at the same time.

This is achieved by an implant as mentioned above, with the first fastening element, the second fastening element and the connecting element having a bioresorbable material.

The broken (fractured) bone can be fixed with the implant. The first fastener in the first Bone part and the second fastening element fastened in the second bone part. The bone parts can then be pulled together with the connecting element and brought into a correct position. The bone parts can preferably be drawn together to such an extent that they rest against one another (in particular at the breaking edges). Subsequent removal of the implant is advantageously not necessary since the first fastening element, the second fastening element and the connecting element have a bioresorbable material. Therefore, the implant in the body or remain in the bone. Furthermore, the rigidity of the support of the bone or the fixation of the bone parts by the implant over time due to the degradation of the bioresorbable material, so that degradation processes of the bone material resulting from a permanent relief of the bone are avoided. Furthermore, the provision of a first and second fastening element for fastening in the respective bone part does not impair the blood supply to the bone or only impairs it to a lesser extent than is the case with a plate that rests on the bone and is fastened to the bone with screws would .

Preferably, the fractured bone is a long bone (human or animal), d. H . a bone with a single medullary cavity, for example: humerus, ulna, radius, femur, tibia, fibula, metacarpal, metatarsal, finger, toe, collarbone. The first fastening element is preferably arranged and/or fastened at least partially in the marrow cavity of the first bone part and the second fastening element is at least partially arranged and/or fastened in the marrow cavity of the second bone part. The implant is particularly suitable for a fracture in the area of the bone shaft (diaphysis) or the metaphysis, but other fractures, for example a femoral neck fracture, can also be fixed with it.

Advantageously, the fastening elements are not introduced via the ends of the bone, but can be introduced into the medullary cavity of the respective bone part at the fracture edge and fastened there. If necessary (and by the medullary space does not exist anyway), part of the bone part can be removed for this purpose, in particular milled out, in order to create a space for the respective fastening element. The respective fastening element is preferably introduced axially into the respective bone.

A recess can then be provided in the radial direction in the first and/or second bone part in order to actuate the first and second interacting connecting devices. In particular, a relative distance between the first and the second fastening element can be changed in an axial direction of the fastening elements with the first and the second interacting connecting devices. In particular, the first and the second fastening element can be pulled together with the cooperating connection devices. The first and/or the second interacting connecting devices can preferably be actuated by rotating the connecting element (relative to the first and/or second fastening element). The first and/or the second interacting connecting devices can preferably be actuated from a radial direction. The first and/or the second interacting connecting devices are preferably set up to convert a circumferential force into a force in an axial direction of the respective fastening element. In the connected state (i.e. the connecting element is connected to the first and to the second fastening element), the connecting element can preferably transmit forces acting on the first fastening element, in particular forces acting in the radial direction, to the second fastening element and vice versa. In particular, the first fastening element cannot be tilted in relation to the second fastening element in the connected state. In particular, the first fastening element and the second fastening element behave in the connected state (and before degradation of the bioresorbable material) as a one-piece unit with respect to a radial force and/or an axial force. Preferably, the connecting element has a first rod, which can be accommodated in a (particularly complementary) recess of the first fastening element, and/or a second rod, which can be received in a (particularly complementary) recess of the second Fastener is receivable on.

The connecting element preferably lies completely in a virtual cylinder, the diameter of which corresponds to twice, preferably 1.5 times, particularly preferably 1.3 times the minimum virtual cylinder that can be circumscribed around the first and the second fastening element; the height of each virtual cylinder being infinite and the central axis of each virtual cylinder running through the central axis of the implant running from the first fastening element to the second fastening element. D. H . , the connecting element does not protrude too far radially . This prevents the connection between the first and second bone parts from becoming blocked.

A bioresorbable (also called biodegradable or bioabsorbable) material is understood to mean a material which, over a period of time in a physiological environment, in particular in the human and/or animal body, is at least 90% by weight, preferably essentially completely, biological, chemical is broken down ( dissolved , decomposed , fissioned and / or eroded ) by physical processes and / or . Degradation of the bioresorbable material may include and/or be followed by removal, restructuring, assimilation, and/or excretion of the degraded material, among other things. For example, the bioresorbable material can be a material that is at least partially, preferably essentially completely, replaced by bone and/or bone marrow during and/or after bioresorption. Replacement with bone and/or bone marrow may involve macroscopic, microscopic, and/or atomic restructuring of the bioresorbable material in situ and/or its removal. The bioresorbable material is preferably degraded or broken down into components. broken down that are metabolizable and/or excretable. The bioresorbable material is preferably within a period of less than 10 years, more preferably within a period of less than 5 years, even more preferably within a period of 2.5 years, to at least 90% by weight, preferably essentially completely, im adult human body degraded. The bioresorbable material is preferably a bioresorbable metal, a bioresorbable metal alloy, a bioresorbable polymer and/or a bioresorbable composite material. The bioresorbable material is preferably based on magnesium and/or iron. The bioresorbable material can have, for example, poly-L-lactide (PLLA), poly-D-lactide (PDLA) or poly-(L-co-D/L-lactide) (PLDLLA).

The bioresorbable material can have one or more bioresorbable substances. The first fastening element, the second fastening element and the connecting element preferably consist of at least 80% by weight, particularly preferably at least 90% by weight, even more preferably at least 95% by weight, of the bioresorbable material. The implant preferably consists overall of at least 80% by weight, particularly preferably at least 90% by weight, even more preferably at least 95% by weight, of the bioresorbable material. The first fastening element, the second fastening element, the connecting element and/or the implant preferably consists of the bioresorbable material.

It is advantageous if a thread of the first fastening element and a first thread of the connecting element complementary to the thread of the first fastening element are provided as first interacting connecting devices, and a thread of the second fastening element and a second thread of the connecting element complementary to the thread of the second fastening element are provided as second interacting connecting devices are provided. The relative distance between the first and the second fastening element can thus be adjusted in a simple manner.

It is preferred if the first thread of the connecting element and the second thread of the connecting element are opposite threads and the thread of the first fastening element and the thread of the second fastening element are opposite threads. D. H . , Advantageously, the first thread of the connecting element and the thread of the second fastener are anticlockwise and the second thread of the connecting element and the thread of the first fastener are clockwise, or the first thread of the connecting element and the thread of the second fastener are clockwise and the second thread thread of the connecting element and the thread of the first fastening element to the left. Thus, a counter-rotating movement of the first and the second fastening element can be achieved by a rotation of the connecting element, ie. H . that the two fastening elements are pulled together by a rotation of the connecting element in one direction and pushed apart by a rotation in the other direction.

It is advantageous if the first thread and the second thread of the connecting element are each external threads (i.e. screw threads) and if the thread of the first fastening element and the thread of the second fastening element are each internal threads (i.e. nut threads). The connecting element can advantageously be partially accommodated in the first fastening element and partially receivable in the second fastening element. It is advantageous if the first thread of the connecting element is provided on the first rod of the connecting element and the thread of the first fastening element is provided in the recess of the first fastening element. It is advantageous if the second thread of the connecting element is provided on the second bar of the connecting element and the thread of the second fastening element is provided in the recess of the second fastening element. A particularly stable connection of the fastening elements to the connecting element is thus achieved.

It is advantageous if the connecting element has a drive profile on a lateral surface, in particular in the form of a toothed wheel. Thus, a force acting in the circumferential direction can easily be exerted on the connecting element, in particular in order to set the relative distance between the first and second fastening element with the first and second interacting connecting devices. In particular, the drive profile has at least one bulge or recess, each of which extends in particular in the axial direction. In particular, the drive profile is set up so that a force can be exerted on the connecting element from the radial direction in the circumferential direction. Milling or the like can be provided in the bone for radial access to the connecting element from at least one side. It is preferred if the first fastening element has at least one spreading device for spreading in the first bone part. This allows compression to be exerted on the surrounding bone tissue. In particular, a circumference of the first fastening element can be increased with the spreading device, so that the first fastening element spreads in the bone. Thus, the first fastening element acts in particular as a dowel. It is preferred if a corresponding hole is first provided in the first bone part, into which the first fastening element can be inserted. The hole can already be completely or partially through the medullary cavity. After the introduction of the first fastening element, it is spread with the spreading device in the first part of the bone. During expansion, a circumference of the first fastening element presses against the inner surface of the hole, resulting in a frictional connection. Furthermore (as explained in more detail below), a form fit is also possible. Advantageously, predetermined breaking points occurring in the bone due to a cutting effect are avoided by fastening using the spreading device (for example in contrast to (self-tapping) screws). During the expansion, the circumference preferably increases, with the diameter at at least one point being increased to at least 1.01 times, preferably 1.05 times, particularly preferably 1.1 times, the original diameter. During expansion, the circumference increases, in which the diameter at least one point is increased by preferably at least 0.1 mm, particularly preferably at least 0.3 mm, even more preferably at least 0.7 mm compared to the original diameter.

It is advantageous if the expanding device has an expansion sleeve, in particular an expanding sleeve, and at least one first wedge element, the expansion sleeve being able to be pushed onto the first wedge element in the direction of an increasing cross section of the first wedge element. By pushing on the expansion sleeve in the direction of the increasing cross-section of the first wedge element, expansion, ie an increase in circumference, can be achieved. The expansion sleeve is preferably (at least along a limited section in the axial direction) on the jacket surface of a (virtual) cylinder or a (virtual) truncated cone. The expansion sleeve preferably has a thickness (in cross section parallel to the axial direction) of between 0.1 and 5 mm. A lateral surface of the first wedge element is preferably frustoconical in a conical section. The expansion sleeve can also be partially pushed onto the first wedge element in the released state.

It is preferred if the expanding device has a second wedge element, in which case the expanding sleeve can be pushed onto the second wedge element in the direction of an increasing cross-section of the second wedge element. The direction of increasing cross-section of the second wedge member is preferably opposite to the direction of increasing cross-section of the first wedge member. Preferably, the cross section increases in each case in the direction facing away from the other wedge element. Thus, at two ends or A spreading takes place on two sides of the expansion sleeve, with the two sides having different, essentially mirrored, angles to the axial direction. The first wedge element and the second wedge element can preferably be moved in relation to one another. A lateral surface of the second wedge element is preferably frustoconical in a conical section. The expansion sleeve can also be partially pushed onto the second wedge element in the released state. The expansion sleeve preferably lies at least partially between the first and the second wedge element and/or connects them.

It is advantageous if the first fastening element has a pull rod, with which the first wedge element can be displaced, so that the expansion sleeve is pushed onto the first wedge element in the direction of the increasing cross section of the first wedge element, and so that the expansion sleeve is preferably pushed towards the second wedge element the increasing cross-section of the second wedge element is postponed. The expansion sleeve and the first wedge element are preferably displaceable relative to one another with the pull rod. However, the first and the second wedge element can also be displaceable relative to one another, as a result of which the expansion sleeve can be pushed onto the first and the second wedge element. It is preferred if the first wedge member and the tie rod have cooperating threads. The first wedge element can be displaced with the cooperating threads and the expansion sleeve can thus be pushed onto the first wedge element. Preferably, the pull rod on the one hand and the expansion sleeve or the second wedge element on the other hand each have a stop element which blocks displacement of the pull rod relative to the expansion sleeve or the second wedge element in at least one axial direction, with the direction preferably being in the direction of increasing the increasing Cross-section of the first wedge element on which the expansion sleeve is pushed shows. This ensures that when the wedge element is displaced with the help of the cooperating thread, the expansion sleeve is expanded on the first wedge element and preferably on the second wedge element. The pull rod can also be made in one piece with the expansion sleeve or the second wedge element.

It is preferred if the tie rod has a screw head drive element at one of its ends. With this, a torque can be exerted on the pull rod at one end of the pull rod in order to move the first wedge element and to spread the expansion sleeve. The screw head drive element is in particular in the form of an internal screw head profile. The first fastening element is braced in particular in the bone before it is connected to the connecting element.

It is advantageous if the screw head drive element is arranged radially inside the thread of the first fastening element. D. H . , the screw head drive element preferably has a smaller radial extent from a central axial axis than the thread of the first fastening element. The thread of the first fastening element is preferably provided on (in particular in) the second wedge element. It can also be provided on the pull rod, the first wedge element or the expansion sleeve.

It is preferred if the expansion sleeve has at least two of an edge of the expansion sleeve that delimits the expansion sleeve in an axial direction Expansion sleeve has running incisions. Wings are thus preferably formed between the incisions, which are spread open in particular when pushed onto the first wedge element. This simplifies the expansion of the expansion sleeve (even when using a very stiff material for the expansion sleeve).

It is advantageous if the expansion sleeve has at least two incisions running from one expansion sleeve in the other axial direction-limiting edge of the expansion sleeve. In particular, wings are also formed between these incisions. This makes it easier to spread the expansion sleeve outwards on both sides.

It is preferred if the expansion sleeve of the expansion device has grooves and/or ribs running in the circumferential direction, in particular circumferentially, on the outer lateral surface. With these, the stability of the attachment of the first attachment element to the first bone part can be improved in the axial direction. In particular, a low form fit can thus also be achieved. The compression with the bone is improved by the grooves and/or ribs. The grooves and/or ribs running in the circumferential direction are formed by a height difference of preferably less than 2 mm, more preferably less than 1 mm, even more preferably less than 0.5 mm or less than 0.3 mm and/or preferably more formed as 0.05 mm. With these values, it is advantageously avoided that breaking edges/predetermined breaking points arise on the first bone part.

It is advantageous if the expansion sleeve of the expansion device has grooves and/or ribs running obliquely to the circumferential direction, in particular running axially, on the outer lateral surface. In this way, twisting of the expansion sleeve relative to the first bone can be prevented. The grooves and/or ribs running obliquely to the circumferential direction are formed and/or preferred by a height difference of preferably less than 2 mm, particularly preferably less than 1 mm, even more preferably less than 0.5 mm or less than 0.3 mm formed more than 0.05 mm. At these values, it is advantageous avoided that demolition edges / predetermined breaking points arise on the first bone part.

It is preferred if the first fastening element has at least one further spreading device for spreading in the first bone part, the further spreading device being designed in particular according to one of the embodiments described herein for the spreading device. The spreading device and the further spreading device preferably have the same features. Thus, the stability in the first bone part can be improved. Two or more further spreading devices can also be provided.

It is advantageous if the additional expansion device has: an additional expansion sleeve, an additional first wedge element, wherein the additional expansion sleeve can be pushed onto the additional first wedge element in the direction of an increasing cross section of the additional first wedge element, and an additional second wedge element, wherein the additional expansion sleeve can be pushed onto the additional second wedge element in the direction of an increasing cross-section of the additional second wedge element.

It is preferred if the further first wedge element can also be displaced with the pull rod of the first fastening element, so that the further expansion sleeve is pushed and spread open onto the further first wedge element and preferably the further second wedge element. It is preferred if the additional first wedge element and the tie rod have cooperating threads with which the additional first wedge element can be displaced. In this case, the expansion sleeve can also be pushed onto the first wedge element without the first wedge element and the tie rod having cooperating threads, since tightening the first further wedge element can also result in compression in the area of the first wedge element. The other first wedge element is preferably arranged further away from the connecting element in the axial direction than the first wedge element. It is preferred if the first wedge element of the spreading device and the further second wedge element of the further spreading device are connected to one another, so that a displacement of the first wedge element of the spreading device leads to the same displacement of the further second wedge element of the further spreading device, with the first wedge element of the spreading device and the further second wedge element of the further spreading device are in particular made in one piece. In the case of a one-piece design, the first wedge element and the additional second wedge element essentially form a double wedge.

It is advantageous if the bioresorbable material contains magnesium, preferably a magnesium alloy, in particular containing between 0.0 and 10.0% by weight zinc. The magnesium alloy preferably has (in % by weight): optionally more than 0.0 up to 7.0% zinc; optionally more than 0.0 up to 1.0% zirconium; optionally greater than 0.0% up to 1.0% calcium; optionally more than 0.0 up to 1.0% manganese; optionally greater than 0.0% up to 0.5% silicon; optionally more than 0.0 up to 1.0% silver; optionally maximum up to 0.5% aluminum; and optionally at least one element selected from the group consisting of greater than 0.05% up to 0.6% yttrium; more than 0.05 up to 4.0% ytterbium; more than 0.05 up to 4.0% gadolinium.

Preferably, the bioresorbable material comprises a magnesium alloy containing (in percent by weight): more than 0.0% up to 7.0% zinc; optionally more than 0.0 up to 1.0% zirconium; optionally greater than 0.0% up to 1.0% calcium; optionally more than 0.0 up to 1.0% manganese; optionally greater than 0.0% up to 0.5% silicon; optionally more than 0.0 up to 1.0% silver; maximum up to 0.5% aluminum; and at least one element selected from the group consisting of more than 0.05 up to 0.6% yttrium; more than 0.05 up to 4.0% ytterbium; more than 0.05 up to 4.0% gadolinium;

The remainder is magnesium and manufacturing-related impurities.

The bioresorbable material preferably has a magnesium alloy according to one of the embodiments described in AT 510087 A1.

The second fastening element can be designed according to an embodiment described in connection with the first fastening element. In particular, the second fastening element is designed like the first fastening element, but is mirrored to it (about a plane of symmetry running through the connecting element).

The invention is explained in detail below with reference to a preferred exemplary embodiment illustrated in the drawings, to which, however, it should in no way be restricted.

Fig. 1 shows schematically an embodiment of the implant in a fractured bone.

FIG. 2 schematically shows the same embodiment of the implant as FIG. 1 in a sectional view along the plane AA (without bone).

FIG. 3 schematically shows the same embodiment of the implant as FIG. 1, with the first fastening element, the connecting element and the second fastening element not being connected to one another.

FIG. 4 schematically shows the same embodiment of the implant as FIG. 1 in an exploded view.

1 shows an embodiment of the implant 1 for fixing a first bone part 2 and a second bone part 3 of a fractured bone in the bone (but in the non-expanded position). 2 shows the implant 1 in a sectional representation along the plane AA. Fig. 3 shows the im plantat 1 in a partially disassembled state and FIG. 4 shows the implant 1 in an exploded view.

The implant 1 has a first fastening element 4 for fastening in the first bone part 2 and a second fastening element 5 for fastening in the second bone part 3 . In Fig. 1 these are shown in the bone-fixed condition. The first fastening element 4 and the second fastening element 5 are provided in particular in the marrow cavity of the respective bone part 2 , 3 . Furthermore, a connecting element 6 is provided for connection to the first fastening element 4 and to the second fastening element 5 . The connecting element 6 and the first fastening element 4 have first interacting connecting devices 7 and the connecting element 6 and the second fastening element 5 have second interacting connecting devices 8 with which a relative distance between the first fastening element 4 and the second fastening element 5 can be changed. Thus, after the attachment of the first attachment element 4 in the first bone part 2 and the second attachment element 5 in the second bone part 3, the first bone part 2 and the second bone part 3 can be pulled together, preferably in such a way that their breaking edges abut one another.

The first fastening element 4 , the second fastening element 5 and the connecting element 6 have a bioresorbable material. As a result, the implant 1 can remain in the bone and does not have to be removed. Furthermore, as a result, the load on the bone decreases over time and with increasing degradation of the bioresorbable material, so that degradation processes of the bone substance that occur as a result of such a load reduction can be avoided or reduced.

As the first interacting connecting devices 7 , the first fastening element 4 has a thread 9 and the connecting element 6 has a first thread 10 complementary to the thread 9 of the first fastening element 4 . (The threads are partially symbolized by thick lines.) As the second interacting connecting devices 8, the second fastening element 5 has a thread 11 and the connecting element 6 has a thread 11 of the second fastener 5 complementary second thread 12 on. The first thread 10 of the connecting element 6 and the second thread 12 of the connecting element 6 are opposite threads and the thread 9 of the first fastening element 4 and the thread 11 of the second fastening element 5 are opposite threads. Thus, by rotating the connecting element 6, an opposite displacement of the first fastening element 4 and the second fastening element 5 can be achieved.

The first thread 10 and the second thread 12 of the connecting element 6 are each external threads and the thread 9 of the first fastening element 10 and the thread 11 of the second fastening element 5 are each internal threads. The first thread 10 and the second thread 12 of the connecting element 6 are each provided on a rod extending in an axial direction 33, and the first thread 9 of the first fastening element 10 and the thread 11 of the second fastening element 5 on the inner surface of a rod complementary to the rod Recess of the respective fastening element 4 , 5 . This connection also improves the power transmission from the first fastening element 4 via the connecting element 6 to the second fastening element 5 and vice versa. The axial direction 33 is indicated with a double arrow (cf. FIG. 2). Both orientations can be understood by the axial direction 33 .

The connecting element 6 has a drive profile 14 in the form of a toothed wheel on a lateral surface 13 . With this, a torque can be exerted on the connecting element 6 and this can be rotated.

The first fastening element 4 has a spreading device 15 and a further spreading device 27 for spreading in the first bone part 2 . The expanding device 15 has an expanding sleeve 16 and a first wedge element 17 , the expanding sleeve 16 being able to be pushed onto the first wedge element 17 in the direction of an increasing cross section of the first wedge element 17 . Furthermore, the spreading device 15 has a second wedge element 18, the spreading sleeve 16 further extending in the direction of an increasing cross section of the second wedge element 18 on the two te wedge element 18 can be pushed on. The direction of increasing cross section of the second wedge element 18 is opposite to the direction of increasing cross section of the first wedge element 17 .

The further spreading device 27 has a further spreading sleeve 28 . Furthermore, the further spreading device 27 has a further first wedge element 29 , wherein the further spreading sleeve 27 can be pushed onto the further first wedge element 29 in the direction of an increasing cross section of the further first wedge element 29 . Furthermore, the further spreading device 27 has a further, second wedge element 30 , with the further spreading sleeve 28 being able to be slid onto the further, second wedge element 30 in the direction of an increasing cross section of the further, second wedge element 30 . The first wedge element 17 of the spreading device 15 and the further second wedge element 30 of the further spreading device 27 are connected to one another, so that a displacement of the first wedge element 17 of the spreading device 15 leads to the same displacement of the further second wedge element 30 of the further spreading device 27. In this embodiment, the first wedge element 17 of the spreading device 15 and the further second wedge element 30 of the further spreading device 27 are designed in one piece.

The first fastening element 4 has a pull rod 19 with which the first wedge element 17 of the expansion device 15 (and thus likewise the further second wedge element 30 of the further expansion device 27 ) and the further first wedge element 29 can be displaced so that the expansion sleeve 16 opens the first wedge element 17 and the second wedge element 18 and the further expansion sleeve 28 is pushed onto the further first wedge element 29 and the further second wedge element 30 in the direction of the increasing cross section of the respective wedge element 17 , 18 , 29 , 30 . For this purpose, the pull rod 19 and the further first wedge element 29 have threads 34 that work together. Furthermore, the pull rod 19 on the one hand and the second wedge element 18 on the other hand each have a stop element 31 , 32 . The stop elements 31, 32 block a displacement of the pull rod 19 to the second wedge element 18 in at least one axial direction, the axial direction increasing in the direction of increase Cross section of the first wedge element 17 or. the further first wedge element 29, on which the expansion sleeve 16 or the further expansion sleeve 28 is pushed on, shows. The additional first wedge element 29 can thus be pulled together with the pull rod 19 to form the second wedge element 18, as a result of which the expansion sleeve 16 is spread open on the first wedge element 17 and the second wedge element 18 and the additional expansion sleeve 28 on the additional first wedge element 29 and the another second wedge element 30 is spread open zt.

The displacement of the first wedge element 17 relative to the second wedge element 18 is approximately half the displacement of the further first wedge element 29 relative to the second wedge element 18 . In the process, the first wedge element 17 is essentially pushed along in part by the further expansion sleeve 28 . The restoring forces of the additional expansion sleeve 28 and the expansion sleeve 16 ensure that both expansion sleeves are expanded to a similar extent. Alternatively or additionally, the first wedge element 17 and the tie rod 19 can also have cooperating threads, whereby in this embodiment these should be designed in such a way that the rotation of the tie rod 19 through a certain angle causes a displacement of the first wedge element 17 that is approximately half as large as the displacement of the further first wedge element 29 .

In order to facilitate the rotation of the pull rod 19, the pull rod 19 has a screw head drive element 21 at one of its ends. The screw head drive element 21 is arranged radially inside the thread 9 of the first fastening element 4 .

The expansion sleeve 16 has at least two incisions 23 running from an edge 22 of the expansion sleeve that delimits the expansion sleeve 16 in an axial direction 33 , between which incisions 23 are formed. The expansion sleeve 16 also has at least two incisions 25 running from an edge 24 of the expansion sleeve 16 that delimits the expansion sleeve 16 in the other axial direction 33 , between which in turn wings (looking in the other axial direction) are formed. With these, the expansion sleeve 16 is opened by the first wedge element 17 (Regarding the incisions 23) and simplified by the second wedge element 18 (relating to the incisions 25).

Furthermore, the expansion sleeve 16 of the expansion device 15 has grooves running in the circumferential direction on the outer lateral surface 26 .

The other expansion sleeve 28 is designed the same as the expansion sleeve 16 . The second fastening element 5 is designed analogously to the first fastening element 4 , mirrored around the connecting element 6 .

Claims

Patent claims :

1. Implant (1) for fixing a first bone part (2) and a second bone part (3) of a fractured bone, having:

- A first fastening element (4) for fastening in the first bone part (2);

- A second fastening element (5) for fastening in the second bone part (3);

- a connecting element (6) for connection to the first fastening element (4) and to the second fastening element (5), wherein the connecting element (6) and the first fastening element (4) have first interacting connecting devices (7) and the connecting element (6) and the second fastening element (5) has second cooperating connecting means (8) so that a relative distance between the first fastening element (4) and the second fastening element (5) can be changed; characterized in that the first fastening element (4), the second fastening element (5) and the connecting element (6) have a bioresorbable material.

2. Implant (1) according to claim 1, characterized in that a thread (9) of the first fastening element (4) and a first thread (10 ) of the connecting element (6) are provided and as second interacting connecting devices (8) a thread (11) of the second fastening element (5) and a second thread (12) of the connecting element (6 ) are provided.

3. Implant (1) according to claim 2, characterized in that the first thread (10) of the connecting element (6) and the second thread (12) of the connecting element (6) are opposite threads and that the thread (9) of the first fastening element

(4) and the thread (11) of the second fastening element (5) are opposite threads.

4. Implant (1) according to one of claims 2 or 3, characterized in that the first thread (10) and the second thread (12) of the connecting element (6) are each external threads and that the thread (9) of the first fastening element ( 10) and the thread (11) of the second fastening element (5) are each internal threads.

5. Implant (1) according to one of the preceding claims, characterized in that the connecting element (6) on a lateral surface (13) has a drive profile (14), in particular in the form of a gear wheel.

6. Implant (1) according to one of the preceding claims, characterized in that the first fastening element (4) has at least one spreading device (15) for spreading in the first bone part (2).

7. Implant (1) according to claim 6, characterized in that the expansion device (15) has an expansion sleeve (16), in particular an expansion sleeve, and at least one first wedge element

(17), wherein the expansion sleeve (16) can be pushed onto the first wedge element (17) in the direction of an increasing cross section of the first wedge element (17).

8. Implant (1) according to claim 7, characterized in that the expansion device (15) has a second wedge element (18), the expansion sleeve (16) further in the direction of an increasing cross-section of the second wedge element (18) on the second wedge element ( 18) can be postponed.

9. Implant (1) according to one of Claims 7 or 8, characterized in that the first fastening element (4) has a pull rod (19) with which the first wedge element (17) can be displaced, so that the expansion sleeve (16) rests on the first wedge element (17) is slid in the direction of the increasing cross section of the first wedge element (17) and so that preferably the expansion sleeve (16) onto the second wedge element (18) in the direction of the increasing cross section of the second wedge element

(18) is postponed.

10. Implant (1) according to claim 9, characterized in that the first wedge element (17) and the pull rod (19) have cooperating threads.

11. Implant (1) according to one of claims 9 or 10, characterized in that the pull rod (19) has a screw head drive element (21) at one of its ends.

12. Implant (1) according to claim 11 and according to claim 3, characterized in that the screw head drive element (21) is arranged radially inside the thread (9) of the first fastening element (4).

13. Implant (1) according to one of claims 7 to 12, characterized in that the expansion sleeve (16) has at least two incisions (23 ) having.

14. Implant (1) according to claim 13, characterized in that the expansion sleeve (16) has at least two incisions (25) running from an edge (24) of the expansion sleeve (16) delimiting the expansion sleeve (16) in the other axial direction.

15. Implant (1) according to one of claims 7 to 14, characterized in that the expansion sleeve (16) of the expansion device (15) has grooves and/or ribs running in the circumferential direction on the outer lateral surface (26).

16. Implant (1) according to one of claims 7 to 15, characterized in that the expansion sleeve (16) of the expansion device (15) on the outer lateral surface (26) has grooves and/or ribs running obliquely to the circumferential direction, in particular running axially .

17. Implant (1) according to one of Claims 6 to 16, characterized in that the first fastening element (4) has at least one further spreading device (27) for spreading in the first bone part (2), the further spreading device (27) being in particular according to one of claims 7 to 16 is formed. 18. The implant (1) according to claim 17, characterized in that the additional expansion device (27) has: an additional expansion sleeve (28), an additional first wedge element (29), the additional expansion sleeve (28) moving in the direction of an increasing cross section of the further first wedge element (29) can be slid onto the further first wedge element (29), and a further second wedge element (30), wherein the further expansion sleeve (28) in the direction of an increasing cross-section of the further second wedge element (30) onto the further second wedge element (30) can be postponed.

19. Implant (1) according to claim 18, characterized in that the first wedge element (17) of the spreading device (15) and the further second wedge element (30) of the further spreading device

(27) are connected to each other, so that a displacement of the first wedge element (17) of the spreading device (15) leads to the same displacement of the further second wedge element (30) of the further spreading device (27), the first wedge element (17) of the spreading device (15 ) and the further second wedge element (30) of the further spreading device (27) are in particular made in one piece.

20. Implant (1) according to one of the preceding claims, characterized in that the bioresorbable material comprises magnesium, preferably a magnesium alloy, the magnesium alloy preferably comprising: optionally more than 0.0 up to 7.0% zinc; optionally more than 0.0 up to 1.0% zirconium; optionally greater than 0.0% up to 1.0% calcium; optionally more than 0.0 up to 1.0% manganese; optionally greater than 0.0% up to 0.5% silicon; optionally more than 0.0 up to 1.0% silver; optionally maximum up to 0.5% aluminum; and optionally at least one element selected from the group consisting of greater than 0.05% up to 0.6% yttrium; more than 0.05 up to 4.0% ytterbium; more than 0.05 up to 4.0% gadolinium.