DE102015209520B3 - Modular stem endoprostheses - Google Patents

Abstract

A modular stem endoprosthesis (200) having a stem member (303), a sealing member (151), and an interconnect member (100) connectable to the stem member (303) that is directly or indirectly connectable to a hinge module member (300), the seal member (30) 151) between the interconnect member (100) and the shaft member (303) to seal the modular stem endoprosthesis (200) against ingress of liquid between the interconnect member (100) and the stem member (303), characterized in that the Interconnecting member (100) and the shaft member (303) by a conical connection comprising a female cone (103) and a male cone (304) are connectable to each other.

Description

The present invention relates to a modular stem endoprosthesis, in particular a modular stem endoprosthesis for a femoral shaft or a tibial shaft.

Endoprostheses, such as permanently remaining in the body and a damaged joint at least partially replacing implants are called, represent a kind of treatment of joints that z. B. be destroyed by arthritis, gout or trauma. Today, endoprosthesis are available for a large number of joints, such. As hip joints, knee joints, shoulder joints, rarely hocks, elbow joints and finger joints. A large proportion of the endoprostheses used represent knee endoprostheses and hip endoprostheses, the z. For example, in 2012 they together accounted for more than 90% of the prostheses used.

Patients who have undergone an endoprosthesis implantation are on average getting younger and therefore more active. This means that in spite of the average lifetime of an endoprosthesis of more than 10 years in an increasing number of patients with maintenance measures on endoprostheses due to wear and tear is expected. This, as well as an optimal adaptation of an endoprosthesis to the physical conditions of a single patient, mean that recent developments here aim at a modular design of endoprostheses, so that for a patient individual prosthesis elements are appropriately selected, so that the endoprosthesis to the patient optimally is adjusted. As a result, on the one hand an increase in the life of an endoprosthesis can be achieved, as well as the influence of the endoprosthesis on the body can be minimized. Furthermore, modular endoprostheses provide the advantage that only individual parts of the prosthesis need to be replaced or renewed if necessary. As a result, interventions necessary for maintenance measures have as little effect as possible on the human body. It is thus z. B. possible that a prosthesis inserted into a bone is not completely removed from the bone and an excessive loss of bone material can be kept correspondingly low.

document EP 0 121 491 B1 shows an implant, consisting of at least two parts, of which the first is plugged onto a conical pin on the second part, wherein the pin in the region of the widening cone end has a thread with a nut which is in the direction of the first plugged part in the The way is screwed that it releases from the pin.

Furthermore, the nut at that end, which faces away from the pin, a thread-sealing, annular projection on.

In view of the above explanations, the goal in the development of endoprostheses is to increase as far as possible the life of endoprostheses, which is accompanied by a reduction of circumstances leading to a deterioration or early wear of an endoprosthesis.

The inventors have recognized that body fluids such. As blood and tissue fluids, can lead to damage of endoprostheses by corrosion at joint surfaces in modular endoprostheses. It is therefore proposed in a first aspect of the invention to provide a modular stem endoprosthesis, in particular for a femoral shaft or for a tibial shaft. In illustrative embodiments herein, the modular stem endoprosthesis includes a stem member and a connecting member connectable to the stem member that is directly or indirectly connectable to a hinge module member, particularly a neck member for supporting a ball head or tibial tray. The modular stem endoprosthesis further includes a sealing member disposed between the connecting member and the stem member for sealing the modular stem endoprosthesis against ingress of liquid between the intermediate connective member and the stem member. This prevents the occurrence of corrosion at modular interfaces caused by the entry of blood or tissue fluid. Furthermore, the intermediate connection element and the shaft element can be connected to one another by a conical connection comprising a female cone and a male cone, wherein an efficient connection between the intermediate connection element and the shaft element is provided.

In another illustrative embodiment of the first aspect, the modular stem endoprosthesis further includes a closure screw attached to the intermediate member for attachment of the intermediate connector to the stem member, and further another sealing member disposed between the closure screw and the intermediate connector about the modular one Seal stem endoprosthesis against the ingress of liquid between the screw plug and the intermediate connector. This provides a reliable connection between the intermediate connection element and the shaft element, while at the same time reducing a risk of occurrence of corrosion between the plug and the intermediate connector.

In a more advantageous illustrative embodiment herein, the sealing element has a passage opening whose diameter is less than or equal to a smallest diameter of the male cone. This permits stripping of fluid present during operative engagement with the male cone when the sealing member is placed on the tapered connection between the intermediate connector and the shaft member.

In a further advantageous embodiment herein, the sealing element has at least one wiper lip, which is designed to wipe off a liquid wetting the male cone when the sealing element is slipped over the male cone. A wiper lip provides a simple and reliable way to provide a wiping function on the sealing element.

In a further illustrative embodiment of the first aspect, the sealing element is designed as an O-ring seal. An O-ring seal provides a simple and efficient seal.

In a further illustrative embodiment of the first aspect, the intermediate connection element and / or the shaft element has at least one annular groove at the interfaces that come into contact for positioning the sealing element. The annular groove thus prevents a misplacement or slipping of the sealing element, so that the seal against the entry of liquid is improved.

In a further illustrative embodiment of the first aspect, the interconnecting member and the shaft member are formed of the same material. This further reduces the risk of corrosion occurring.

In a second aspect of the invention, a modular stem endoprosthesis, in particular for a femoral shaft or a tibial shaft, is provided. In one illustrative embodiment, the modular stem endoprosthesis includes an interconnecting member that is directly or indirectly connectable to a hinge module member, particularly a neck member for supporting a ball head or tibial tray, and a shaft member connectable to the interconnect member via a closure screw. Further, the modular stem endoprosthesis includes a sealing member disposed between the closure screw and the interconnecting member to seal the modular stem endoprosthesis against ingress of liquid between the closure screw and the interconnect member.

In a further illustrative embodiment, the modular stem endoprosthesis according to the first or second aspect of the invention further comprises a joint modulus member having a male cone for forming a tapered joint with other modular elements of a joint module, such as a ball joint of a hip joint or a tibial plate of a knee joint Cone is formed a groove for positioning a sealing element. The groove enables reliable positioning and attachment of the sealing element on the cone of the joint module element.

Further advantages and features of the various embodiments of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

1a FIG. 4 illustrates a modular stem endoprosthesis having a joint module element for a knee joint in accordance with some illustrative embodiments of the invention; FIG.

1b schematically illustrates in cross-sectional view a modular stem endoprosthesis with a hip joint articulation element according to some illustrative embodiments of the invention;

2a schematically illustrates a sealing element disposed on a cone according to some illustrative illustrative embodiments of the invention;

2 B a sealing element of further illustrative embodiments of the invention; and

2c schematically illustrates in a cross-sectional view a sealing element according to yet other illustrative embodiments of the invention.

1a schematically shows a cross-sectional view of a knee joint prosthesis module 200 in accordance with some illustrative embodiments of the invention. The knee joint prosthesis module 200 comprises a joint module element designed as a femoral component 300 , a shaft element 303 and an interconnecting element 100 , In addition, the knee joint prosthesis may include a tibial tray (not shown) and an artificial meniscus (not shown).

The joint module element 300 includes an articulation surface 301 , on which in the implanted knee joint prosthesis module 200 a sliding plate (not shown) can rest. The articulation surface 301 and the surface of the slide plate (not shown) are formed such that the joint module element 300 and a tibial tray (not shown) with the slide plate (not shown) mounted thereon can perform a roll-slide rotational movement that corresponds to, or at least approximates, the motion sequences occurring in natural human knee joint.

The joint module element 300 also includes a female cone 302 which is for connecting the joint module element 300 with the interconnecting element 100 can be used over a cone connection. In some illustrative embodiments may be on the side of the female cone 302 , the articulation surface 301 is facing and on which the top surface of the female cone 302 located, a hole 306 be provided by a locking screw 320 is guided, which as fastening means for bracing the cone connection between the joint module part 300 and the interconnecting element 100 serves.

As shown in 1a includes the interconnecting element 100 a first submodule 101 and a second sub-module 102 , The first submodule 101 has a female cone 103 on, for producing a cone connection between the interconnecting element 100 and the shaft member 303 suitable is. The second submodule 102 includes a male cone 107 which is for making a cone connection between the interconnecting element 100 and the joint module element 300 , especially the female cone 302 , is trained.

According to some illustrative embodiments, the hinge module element may be 300 be formed of a cobalt-chromium alloy, for example CoCrMo. A joint module element formed from a cobalt-chromium alloy 300 has z. B. particularly good sliding properties on a sliding plate (not shown), and is therefore exposed to less wear than other materials, such as titanium or titanium alloys.

The shaft element 303 is usable in a femur of a patient. In some embodiments, the shaft member 303 be designed for a cementless implantation. For this purpose, the shaft element 303 have grooves on its outer side, along a longitudinal direction of the shaft member 303 run, and in the area that comes into contact with the bone of the patient, he may have a rough surface, the ingrowth of the shaft element 303 favored in the bones. In some embodiments, the shaft member 303 titanium or a titanium alloy, for example TiAl ₆ V ₄ , be formed. In other embodiments, the shaft member 303 be designed for a cemented implantation in the femur of the patient. In such embodiments, the shaft member 303 no grooves on.

According to some illustrative embodiments, the shaft member comprises 303 a male cone 304 for joining the shaft element 303 with the interconnecting element 100 can be used by a cone connection. In the male cone 304 can be a longitudinal bore 307 be provided with an internal thread into which a screw can be screwed, which serves as a fastening means for bracing the cone connection between the shaft member 303 and the interconnecting element 100 serves.

In some illustrative embodiments, the part of the shaft member may 303 inserted into the patient's bone, have a curvature corresponding to the curvature of the human femur. When inserting the prosthesis 200 is the orientation of the shaft member 303 by aligning the curvature of the shaft member 303 to set the curvature of the femur, so that the shaft element 303 is not inserted into the femur at any angle about a longitudinal axis of the femur. In other embodiments, the shaft member 303 also be straight.

According to some illustrative embodiments of the invention, the shaft member 303 in turn be composed of a plurality of individual shaft module elements, which are the shaft element 303 form. As a result, for example, a modulation of a desired curvature of the femoral stem 303 and / or a length adjustment of the shaft element 303 respectively.

The male cones 304 . 107 can each have an angle between its cone axis and its lateral surface, which is equal to an angle between the cone axis and the lateral surface of a corresponding female cone 103 . 302 is in which the male cone 304 . 107 is to use to make a cone connection. Additionally or alternatively, each of the male cones has 304 . 107 a corresponding size, so that the cones 304 . 107 by friction between the lateral surfaces of the respective female cones 103 . 302 lock into each other. In some illustrative examples, the cones 304 . 103 . 107 and 302 an angle from a range of 0.5 ° to 5 °, about an angle of 1 ° between their lateral surfaces and their cone axes. Angles of this size have proven to be particularly suitable for producing stable cone connections.

In some illustrative embodiments of the invention, the first sub-module 101 and the second sub-module 102 of the interconnecting element 100 with the help of an internal thread 104 at the first submodule 101 and an external thread 108 at the second submodule 102 be attached to each other. Here are the internal thread 104 and the female cone 103 on opposite sides of the first sub-module 101 of the interconnecting element 100 ,

For making a cone connection between the male cone 304 and the female cone 103 will be a screw 106 through a longitudinal bore in the first submodule 101 through into a hole 307 of the shaft member 303 used. By screwing in the thread of the screw 106 into the internal thread of the bore 307 is through the screw 106 a force on the shaft element 303 exercised by the male cone 304 of the shaft member 303 in the female cone 103 of the first submodule 101 of the interconnecting element 100 is pressed into it. This will create a positive connection between the cones 304 . 103 made or consolidated.

Accordingly, in accordance with some illustrative embodiments of the invention, there is provided a modular stem endoprosthesis for a knee joint having an interconnecting member 100 that with a joint module element 300 a knee joint is connectable, and a shaft member 303 provided.

To prevent ingress of liquid, such. Blood and / or tissue fluid, between the interconnecting member 100 and the shaft member 303 at the cone junction 304 . 103 becomes a sealing element 151 between the interconnecting element 100 and the shaft member 303 arranged, which prevents the entry of liquid into the cone connection 103 . 304 prevented. Additionally or alternatively, another sealing element 153 at the cone junction 102 . 302 between the interconnecting element 100 and the joint module element 300 be arranged to prevent the entry of liquid into the cone connection. Additionally or alternatively, around the screw 106 in the cone connection between the male cone 304 and the female cone 103 a sealing element 155 be arranged. Illustrative embodiments of the sealing elements 151 to 155 will be below with reference to the 2a to 2c explained in more detail.

Further illustrative embodiments of the invention will be made with reference to FIG 1b described a modular stem endoprosthesis 500 with a shaft element 510 and a joint module element 520 shows. Alternatively, between the shaft member 510 and the joint module element 520 an intermediate connection element (not shown) and / or the shaft element 510 can be composed of several shaft module parts (not shown). In the 1b illustrated modular stem endoprosthesis 500 is used according to illustrative embodiments as a hip endoprosthesis. In this case, the joint module element 520 a neck member of a modular hip endoprosthesis, wherein one of the joint module element 520 protruding male cone 524 a ball head (not shown) of a hip endoprosthesis is arranged.

The shaft element 510 is intended as a tibial shaft of a hip endoprosthesis and can, at least partially, be inserted into a tibia. According to some illustrative embodiments, the shaft member may 510 according to the femoral stem element 303 be formed, with the above statements to the shaft member 303 in 1a is referenced.

The joint module element 520 is by means of a cone connection formed by a male cone 512 of the shaft member 510 and a female cone 522 of the joint module element 520 connected. Alternatively, the shaft element 510 be connected via a corresponding cone connection with an unillustrated interconnecting element, which in turn via a corresponding cone connection with the joint module element 520 connected is. The configuration of the cone connection is not on the in 1b illustrated embodiment limited. Alternatively, the joint module element (or an unillustrated interconnecting element) may comprise a male cone which is provided with a female cone in the shaft element 510 is associated. According to illustrative embodiments, cone connections can be designed in accordance with the cone connections, which in terms of 1a are described above.

To prevent ingress of liquids in cone connections, sealing elements 541 . 542 . 543 used on. As shown in 1b becomes the sealing element 541 at the cone connection between the shaft element 510 and the joint module element 520 arranged. This is the sealing element 541 on the male cone 512 raised or overstretched. Additionally or alternatively, the sealing element 542 between the screw plug 530 and the joint module element 520 arranged. Additionally or alternatively, the sealing element 543 on the male cone 524 arranged. Illustrative examples herein include the male cone 524 a groove into which the sealing element 543 for positioning at least partially introduced. Corresponding grooves are, for example, on the adjusting screw (see. Groove 532 ) and on the male cone 512 (not shown) provided to the sealing element 542 and / or the sealing element 512 to position.

In the 2a to 2c Illustrative embodiments of the sealing elements described above are shown.

2a shows a schematic cross-sectional view of a male cone 610 and a sealing element 620 , The sealing element 620 is shown formed as an O-ring seal. For positioning the sealing element 620 can a groove 612 on the male cone 610 be provided as in 2a is shown. The groove 612 assists in positioning the sealing element 620 on the cone 610 and prevents any slipping of the sealing element 620 from the cone 610 ,

According to some illustrative embodiments, the sealing element 620 an opening 622 with a diameter d2 smaller than or equal to a smallest diameter d1 of the male cone 610 is (d2 ≤ d1). Will the sealing element 620 now on the male 610 raised, so is the sealing element 620 under force on wide and lies on the lateral surface of the male cone 610 sealingly. In a further sliding of the sealing element 620 on the cone to the positioning groove 612 In addition, adhering to the cone liquid, such as blood and / or tissue fluid is stripped off. Thus, the lateral surface of the male cone 610 during application of the sealing element 620 reliable from one the lateral surface of the male cone 610 wetting liquid cleaned. Consequently, it is already ensured in the preparation of the cone connection that in the cone connection no liquid is present, which leads to corrosion and thus deterioration of the cone connection.

2 B shows a sealing element 630 according to another illustrative embodiment. In this case, the sealing element 630 at least one wiper lip 632 on that the inner diameter of the sealing element 630 reduced at least locally. Instead of the lamellar wiper lip according to the invention 632 a Abstreifwulst (not shown) may be formed, which is the inner diameter of the sealing element 630 at least in places reduced compared to an O-ring without a bead. In the 2 B illustrated embodiment with lamellar wiper lip 632 differs from an embodiment not shown with Abstreifwulst in that the blade-like wiper lip 632 is more elastic.

In embodiment with wiper lip, as in 2 B is shown, an inner diameter de3 of the sealing element 630 without wiping lip compared to one through the wiper lip 632 reduced diameter d4 be greater than, for example, a minimum diameter of a male cone (see, for example, diameter d1 of the male cone 610 in 2a ), provided that the inner diameter d4 is smaller than the minimum diameter of a male cone, not shown (see, for example, d1 in FIG 2a ). When using the sealing element 630 out 2 B on the cone 610 out 1 can hold: d3 ≥ d1, as long as d4 ≤ d1.

2c shows, in a schematic cross-sectional view, another illustrative embodiment of the present invention, wherein a sealing element 640 sealing lips 642 which is of a radial orientation, as shown for example in FIG 2 B for the lamellar sealing lips 632 is shown, deviate. The wiper lips 642 are, for example, in places within the sealing element 640 formed and have respect to a Aufreifreifrichtung A, along which the sealing element 640 on a male cone 650 is aufgestreift, an angle β, so that the inner diameter of the sealing element 640 without wiper lip 642 to a minimum inner diameter d5 at the wiper lip 642 is reduced. The angle β is in particular different from an angle α, around which the lateral surface of the male cone 650 is inclined relative to the stripping A direction. The amount of the difference between the angles β and α may, for example, be more than 1 ° or more than 5 ° or more than 10 °. In addition, the inner diameter d5 may be smaller than or equal to the smallest diameter d6 of the male cone 650 be (d5 ≤ d6). When brushing the sealing element 640 on the male cone 650 Thus, any of the lateral surface of the male cone 650 wetting liquid 652 through the wiper lips 642 reliably stripped off. The lips 642 For example, after positioning the sealing element 640 on the male cone 650 , for example, in a groove (not shown), be removed, for example by cutting, tearing off etc. Alternatively, the wiper lips 642 optionally after a purge of liquids, be introduced as an additional seal in the cone connection.

Sealing members, as described above with respect to the various illustrative embodiments, may be formed of polyurethane, silicone, polyethylene, polyetherketone (PEEK), PEKK, or combinations thereof. Alternatively, the sealing element may be formed of a curable polymer which, after being positioned on a male cone, is cured, for example by light, heat and the like (eg a chemical reaction).

Claims (10)

Modular stem endoprosthesis ( 200 ) with a shaft element ( 303 ), a sealing element ( 151 ) and one with the shaft element ( 303 ) connectable interconnection element ( 100 ) directly or indirectly connected to a joint module element ( 300 ) is connectable, wherein the sealing element ( 151 ) between the interconnecting element ( 100 ) and the shaft element ( 303 ) is arranged to the modular stem endoprosthesis ( 200 ) against ingress of liquid between the interconnecting element ( 100 ) and the shaft element ( 303 ), characterized in that the interconnecting element ( 100 ) and the shaft element ( 303 ) by a cone connection comprising a female cone ( 103 ) and a male cone ( 304 ) are connectable to each other. Modular stem endoprosthesis ( 200 ) according to claim 1, further comprising a locking screw ( 106 ) used to attach the interconnecting element ( 100 ) on the shaft element ( 303 ) on the interconnecting element ( 100 ), and another sealing element ( 155 ), the further sealing element ( 155 ) between the screw plug ( 106 ) and the interconnecting element ( 100 ) is arranged to the modular stem endoprosthesis ( 200 ) against ingress of liquid between the screw plug ( 106 ) and the interconnecting element ( 100 ) seal. Modular stem endoprosthesis ( 200 ) according to claim 1 or 2, wherein the sealing element ( 151 ) has a passage opening whose diameter is smaller than or equal to a smallest diameter of the male cone ( 304 ). Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 3, wherein the sealing element ( 151 ) has at least one wiper lip which is suitable for stripping off a male cone ( 304 ) wetting liquid when slipping the sealing element on the male cone ( 304 ) is trained. Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 4, wherein the sealing element ( 151 ) is designed as an O-ring seal. Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 5, wherein the interconnecting element ( 100 ) and / or the shaft element ( 303 ) at least one annular groove at the coming into contact interfaces for positioning of the sealing element ( 151 ) having. Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 6, wherein the interconnecting element ( 100 ) and the shaft element ( 303 ) are formed of the same material. Modular stem endoprosthesis ( 200 ) with an interconnecting element ( 100 ) directly or indirectly connected to a joint module element ( 300 ) is connectable, and a sealing element ( 151 ), characterized in that the modular stem endoprosthesis ( 200 ) via a screw plug ( 106 ) with the interconnecting element ( 100 ) connectable shaft element ( 303 ) and the sealing element ( 151 ) between the screw plug ( 106 ) and the interconnecting element ( 100 ) is arranged to the modular stem endoprosthesis ( 200 ) against ingress of liquid between the screw plug ( 106 ) and the interconnecting element ( 100 ) seal. Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 8, further comprising a joint module element ( 300 ) with a male cone ( 304 ) for forming a cone connection with further modular elements of a joint module, wherein on the cone ( 304 ) a groove for positioning a sealing element ( 151 ) is formed. Modular stem endoprosthesis ( 200 ) according to one of claims 1 to 9, wherein the modular stem endoprosthesis is provided for a femoral shaft or a tibial shaft and the joint module element in the case of a femoral stem is a neck element for holding a ball head or, in the case of a tibial stem, a neck element for holding a tibial plate.

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