BONE IMPLANT SYSTEM, BONE IMPLANT AND METHOD FOR PRODUCING SUCH A BONE IMPLANT

Description

[0001] The invention relates to a bone implant system, in particular for filling bone defects and / or for stabilizing a joint replacement implant. The invention also relates to a bone implant produced using such a bone implant system and a method for producing such a bone implant.

[0002] Bone implants are well known in the field of orthopedic surgery and are used, for example, in joint replacement operations in the knee, hip, shoulder and / or ankle area.

[0003] In knee replacement surgery, existing metaphyseal bone defects in the proximal tibia or distal femur are typically treated with a bone implant. The bone implant is placed prior to the implantation of the actual tibial or femoral joint replacement implant and is intended to fill the bone defect. The bone implant also provides additional stabilization for the joint replacement implant once implanted. Such bone implants are often referred to as cones or metaphyseal cones.

[0004] To ensure successful treatment, the outer contour of the cone must be matched to the inner contour of the bone defect to be treated. For this purpose, one-piece cones are available in various sizes and shapes. However, optimal adaptation to an existing bone defect is not always possible, as a correspondingly adapted cone cannot be manufactured and kept in stock for every conceivable defect geometry. Alternatively, custom-made one-piece cones are occasionally used. However, their production is time-consuming and costly.

[0005] EP 0517030 A2 discloses a bone implant system comprising disc elements of varying thicknesses and outer diameters. The disc elements serve to individually configure a vertebral body implant by stacking the disc elements. For this purpose, the required outer diameter is first determined, and then disc elements of different thicknesses are stacked to achieve the desired implant height. No combination of disc elements with different diameters is provided, which is why the outer contour of the implant cannot be customized, unlike the present invention.

[0006] The object of the invention is to provide a bone implant system, a bone implant and a method for producing such a bone implant, which partially or completely avoid the disadvantages mentioned at the beginning in connection with conventional bone implants.

[0007] This object is achieved by a bone implant system having the features of claim 1, a bone implant having the features of claim 8 and a method having the features of claim 9. Preferred embodiments are the subject of the subclaims and the description.

[0008] The bone implant system according to the invention comprises a plurality of different disc elements with different outer diameters, wherein the disc elements can be axially stacked in different combinations to form different stacking arrangements, wherein the different stacking arrangements have different outer contours due to the different outer diameters of the disc elements, and wherein the disc elements each have a form-fitting section arranged on an upper side and a complementary form-fitting section arranged on an axially opposite lower side, by means of which the disc elements in the different stacking arrangements can be fixed to one another in a form-fitting manner in the radial direction and / or circumferential direction. The solution according to the invention makes it possible to dispense with the time-consuming and cost-intensive production of individualized, one-piece bone implants.At the same time, an improved adaptation of the bone implant to a given geometry of the bone defect to be treated can be achieved compared to conventional, non-individualized bone implants. Simply put, depending on the geometry of the bone defect, several disc elements of the bone implant system are selected and combined axially stacked one above the other in such a way that the outer contour of the resulting stacked arrangement matches the inner contour of the bone defect as required. The different outer diameters of the disc elements and the possibility of stacking the disc elements in different combinations allow for different stacking arrangements and, accordingly, different outer contours.The form-fitting sections and the complementary form-fitting sections serve to form a positive connection between the disc elements in the respective stacking arrangement formed. Simply put, the form-fitting sections of the different disc elements are preferably designed to be the same, similar, consistent, identical, and / or interchangeable. In other words, the design of the form-fitting sections is preferably independent of the outer diameter of the respective disc element. The same preferably applies analogously to the complementary form-fitting sections. This ensures that the disc elements can always be secured to one another, regardless of the selected combination and / or stacking arrangement formed.The plurality of disc elements can, for example, comprise a first disc element with a first outer diameter, a second disc element with a second outer diameter, and a third disc element with a third outer diameter. The outer diameters differ in terms of their diameter dimension and / or shape. In this respect, the disc elements, or more precisely, their outer diameters, can be circular and / or elliptical and / or rounded in the broadest sense.

[0009] Of course, the bone implant system can also comprise multiple disc elements with one and the same outer diameter. For example, multiple first disc elements, multiple second disc elements, and multiple third disc elements can be provided. The different disc elements differ at least with regard to their outer diameter, in particular its dimensions and / or shape. Additionally, disc elements of different thicknesses can be provided, although these do not necessarily have to have different outer diameters. The disc elements are preferably each designed as a circular disc with a circular cross-section. The different outer diameters are preferably dimensioned in gradually stepped dimensions. This allows, in particular, conical outer contours with different cone angles to be formed.The form-fitting sections can each have, in particular, a connecting groove, a connecting pin, a toothing, or the like for positive engagement with one of the complementary form-fitting sections. Accordingly, the complementary form-fitting sections can each have, in particular, a feather key, a receiving bore, a counter-toothing, or the like. The form-fitting sections and / or the complementary form-fitting sections can be formed integrally with the respective disc element. Alternatively, the form-fitting sections and / or the complementary form-fitting sections can be manufactured separately and subsequently joined to the respective disc element.

[0010] In an embodiment of the invention, the disc elements are each ring-shaped and have a preferably identical inner diameter. When axially stacked one above the other, the inner diameters of the disc elements form a preferably circular-cylindrical receiving recess. The receiving recess is intended to accommodate a shaft portion of a joint replacement implant. A circular and / or elliptical ring shape is preferably provided.

[0011] In a further embodiment of the invention, the disc elements each have at least one spacer section extending axially from the top or bottom, allowing the disc elements to be stacked one on top of the other in different stacking arrangements, forming radial gaps. If the bone implant formed from the bone implant system is anchored in the bone defect using a bonding compound, such as bone cement, the radial gaps allow the bonding compound to penetrate between the individual disc elements. This can further stabilize the stacking arrangement formed from the disc elements or the bone implant. In other words, the disc elements can be stacked "on the gap" due to the spacer sections provided. The bonding compound can then pass through these gaps between the individual disc elements.The spacer sections can be formed integrally with the respective disc element. Alternatively, the spacer sections can be manufactured as separate components and then joined to the respective disc element.

[0012] In a further embodiment of the invention, the disc elements each have at least one receiving recess recessed into the top or bottom side, which is provided for receiving a bonding compound. This is particularly advantageous in conjunction with the features of the previous embodiment. If radial gaps are provided, the bonding compound, for example bone cement, can penetrate radially between the disc elements through the radial gaps and be received in the receiving recesses. If no radial gaps are present, the receiving recesses can be filled with the bonding compound before the disc elements are stacked on top of one another. This allows the formed stack arrangement / bone implant to be fixed in place. The receiving recesses can also be referred to as receiving pockets.The mounting recesses preferably do not form a continuous connection between the top and bottom of the respective disc element. This is in contrast to a simple axial bore.

[0013] In a further embodiment of the invention, the form-fitting sections each have at least one axially projecting connecting section, and the complementary form-fitting sections each have at least one receiving bore introduced in the axial direction, or vice versa. The connecting pins preferably protrude from the upper sides of the disc elements. The receiving bores are preferably introduced into the undersides of the disc elements. Alternatively, an arrangement reversed to this can be provided. The connecting pins and the receiving bores are dimensionally coordinated with one another. When the disc elements are positively secured to one another, the connecting pins engage in the receiving bores, so that the stack arrangement formed in each case is fixed in the radial and / or circumferential direction.Compared to other conceivable designs of the form-fitting sections and / or the complementary form-fitting sections, this embodiment of the invention allows for simple manufacture and high load-bearing capacity of the form-fitting connection. Preferably, the form-fitting sections and the complementary form-fitting sections are coordinated with one another in such a way that the disk elements can be secured to one another in different relative rotational positions. This is preferably achieved by having a larger number of receiving bores than a larger number of connecting pins. Preferably, the receiving bores and / or the connecting pins are arranged concentrically in the radial direction.

[0014] In a further embodiment of the invention, the disc elements each have a plurality of connecting pins and / or receiving bores arranged offset in the circumferential direction, wherein the arrangement of the connecting pins and / or the receiving bores of the different disc elements forms an identical drilling pattern. In simple terms, this enables all disc elements to be connected to one another in a form-fitting manner. The drilling pattern of the connecting pins can be characterized by the diameter of the connecting pins, the diameter of a bolt circle on which the plurality of connecting pins of the respective disc element are arranged, a number of connecting pins per bolt circle, and / or an angular position of the connecting pins on the bolt circle. The same applies analogously to the drilling pattern of the receiving bores.Preferably, at least two connecting pins and / or receiving bores are provided and arranged offset by 180° from each other on the respective bolt circle. Of course, more than two connecting pins and / or receiving bores could also be provided. For example, three, four, five, six, or more connecting pins and / or receiving bores. These are preferably arranged offset by 120°, 90°, 72°, or 60° from each other in the circumferential direction.

[0015] In a further embodiment of the invention, at least three, preferably more than six, particularly preferably more than twelve different disc elements are provided. These each have a different outer diameter. Several disc elements with one and the same outer diameter can be provided, so that the bone implant system accordingly has a total of more than the aforementioned at least three, preferably more than six, particularly preferably more than twelve, different disc elements. If, for example, three disc elements of each outer diameter are present, the bone implant system has a total of at least 9, preferably more than 18, particularly preferably more than 36 (different) disc elements.

[0016] The bone implant according to the invention comprises a plurality of disc elements stacked one above the other in the axial direction and having different outer diameters. The stacked disc elements are secured to one another in a form-fitting manner in the radial direction and / or circumferential direction by means of form-fitting sections arranged on the top side of the disc elements and complementary form-fitting sections arranged on the bottom side of the disc elements. The outer diameters differ, in particular, with regard to their dimensions and / or shape. To avoid repetition, reference is made to the description of the bone implant system according to the invention regarding the advantages associated with the design of the bone implant according to the invention. The statements made there also apply mutatis mutandis to the bone implant according to the invention. Preferred embodiments of the bone implant are derived mutatis mutandis from the features of claims 2 to 7.

[0017] The method according to the invention for producing a customized bone implant using a bone implant system according to the preceding description comprises the steps of: detecting an inner contour of a bone defect; determining an outer contour of the bone implant required to fill the bone defect based on the detected inner contour; selecting, stacking, and attaching several different disc elements of the bone implant system, wherein the multiple disc elements are selected and / or stacked based on the determined outer contour. Preferably, the inner contour of the bone defect is detected intraoperatively. The inner contour can be represented, for example, by a 3D data set. The detection is carried out by measurement, for example, using a time-of-flight camera. The required outer contour of the bone implant is determined based on the detected inner contour.The determination is preferably computer-based. The disc elements required to reproduce the required outer contour are selected by medical personnel, preferably a surgeon, from the total number of different disc elements available in the bone implant system. This is also preferably carried out with computer support, for example, using an optimization process set up for this purpose. The selection comprises, on the one hand, the actual selection and, on the other hand, the combination of the disc elements in the axial direction required to reproduce the required outer contour. The selected disc elements are then stacked, preferably manually, and secured to one another in a form-fitting manner in the radial direction and / or circumferential direction using the form-fitting sections and complementary form-fitting sections.The bone implant created in this way can then be inserted into the bone defect and anchored in it in a generally known manner. The selection and assembly of the disc elements does not necessarily have to be performed intraoperatively. Rather, the inner contour of the bone defect can be recorded prior to the surgery, and the selection and assembly of the disc elements can be performed based on this prior to the surgery.

[0018] Further advantages and features of the invention emerge from the claims and from the following description of preferred embodiments of the invention, which are illustrated with reference to the drawings. Fig. 1 shows a schematically simplified representation of an embodiment of a bone implant system according to the invention with several different disc elements, Fig. 2, 3, 4 an exemplary first disc element of the bone implant system according to Fig. 1 in a schematic plan view ( Fig. 2 ), a schematic sectional view along a section line III-III according to Fig. 2 (Fig. 3 ) and a schematic bottom view ( Fig. 4 ), Fig. 5, 6, 7 an exemplary second disc element of the bone implant system according to Fig. 1 in a schematic plan view ( Fig. 5 ), a schematic sectional view along a section line VI-VI according to Fig. 5 (Fig. 6 ) and a schematic bottom view ( Fig. 7 ), Fig. 8, 9, 10an exemplary third disc element of the bone implant system according to Fig. 1 in a schematic plan view ( Fig. 8 ), a schematic sectional view along a section line IX-IX according to Fig. 8 (Fig. 9 ) and a schematic bottom view ( Fig. 10 ), Fig. 11in a comparison to the Fig. 3 , 6 and 9 shows a sectional view rotated by 90° of the first, second and third disc elements in an axially stacked stack arrangement, Fig. 12 the stack arrangement according to Fig. 11 , wherein the disc elements are fixed to one another in a form-fitting manner in the radial direction and / or circumferential direction, Fig. 13 a schematically highly simplified representation of an embodiment of a bone implant according to the invention, which is produced using the bone implant system according to Fig. 1 is formed, wherein the bone implant is implanted proximally into a tibia to fill a bone defect, and Fig. 14 is a schematically greatly simplified flow diagram to illustrate an embodiment of a method according to the invention for producing a bone implant according to the invention.

[0019] According to Fig. 1 is a bone implant system 1 for forming an individualized bone implant 100 ( Fig. 13 ). In the embodiment shown, the bone implant 100 is intended for use in a knee replacement operation and is Fig. 13 shown by way of example in an implanted state. In this implanted state, the bone implant 100 is implanted proximally into a tibia T. In the use shown here, the bone implant 100 primarily fulfills two functions. Firstly, the bone implant 100 fills a metaphyseal bone defect D in the region of the proximal tibia T. Secondly, the bone implant 100 stabilizes a tibial joint replacement implant G. The joint replacement implant G in the present case is a so-called tibial plateau, which is anchored proximally to the tibia T in a manner generally known to those skilled in the art and is designed to interact with other components of a knee joint replacement prosthesis. In order to achieve optimal treatment results, it is desirable that an outer contour A of the bone implant 100 is geometrically matched to an inner contour I of the bone defect D. The outer contour A is based on Fig. 13 drawn in a highly simplified dashed line and offset approximately parallel to the inner contour I.

[0020] Naturally, metaphyseal bone defects can exhibit a wide variety of geometries. To ensure the best possible adaptation to the respective internal contour, customized bone implants are available in the state of the art. These are manufactured as a single piece, so-called "monoblocks," after the geometry of the bone defect has been individually determined. Such custom-made implants can be time-consuming and costly. Furthermore, bone implants specifically designed for this purpose, known as tibial cones, are available on the market in various sizes and shapes. The appropriate selection of the size and / or shape of the bone implant is intended to achieve improved adaptation to the respective internal contour of the bone defect. However, this is not always successful.

[0021] The bone implant system 1 overcomes the disadvantages associated with the prior art and, in particular, allows for the time- and cost-saving production of customized bone implants tailored to an existing defect geometry. The bone implant system 1 is preferably suitable for the above-described use in the context of knee replacement surgery. Nevertheless, the bone implants produced using the bone implant system 1 can also be used in other joint replacement surgeries, for example, in the hip, shoulder, and / or ankle region.

[0022] The bone implant system 1 has several different disc elements 2 to 7 with different outer diameters DA2 to DA7 ( Fig. 1 ).

[0023] Based on Fig. 1 Six disc elements are shown as examples, differing in terms of their outer diameter. It is understood that the bone implant system may have fewer than the six shown, for example two, three, four, five, or more than the six shown, for example seven, eight, nine, ten, different disc elements. This is in Fig. 1 symbolized by the points drawn between the disc elements 6 and 7 and below the disc element 7.

[0024] The Fig. 1 The apparent size ratios between the different outer diameters DA2 to DA7 are to be understood as purely exemplary. It is understood that the different outer diameters may be finer or coarser in designs not shown in the drawings.

[0025] In addition, the bone implant system 1 in the embodiment shown has several identical disc elements for each outer diameter DA2 to DA7. In this respect, one can also speak of a first set of disc elements 2, 2', 2" with the outer diameter DA2, a second set of disc elements 3, 3', 3" with the outer diameter DA3, a third set of disc elements 4, 4', 4" with the outer diameter DA4, etc. Fig. 1 For example, three disc elements per set. In an embodiment not shown in the drawing, only a single disc element is provided per outer diameter. In other embodiments not shown, for example, two, four, five, six, or more disc elements are provided per set. Against this background, the disc elements 2, 2', 2" can each also be referred to as the first disc element. The disc elements 3, 3', 3" can accordingly each be referred to as the second disc element. The disc elements 4, 4', 4" can each be referred to as the third disc element. The naming of the other disc elements of the bone implant system 1 results accordingly. For the sake of brevity, only the first disc element 2, the second disc element 3, the third disc element 4, the fourth disc element 5, etc. will be referred to below.

[0026] In the embodiment shown, the different outer diameters DA2 to DA7 differ only in terms of their dimensions. It is understood that the different outer diameters DA2 to DA7 can alternatively or additionally differ in terms of their shape. In this respect, the circular or annular design of the outer diameters shown in the present figures is to be understood as purely exemplary and is due to the simplified graphic representation. Instead of the shape shown in the drawing, the different outer diameters DA2 to DA7 can, in particular, be elliptical and / or rounded in the broadest sense. For example, an elliptical shape can also be used to treat asymmetrical bone defects.

[0027] The different disc elements 2 to 7 can be axially stacked in different combinations to form different stacking arrangements. An exemplary first stacking arrangement S1 is shown in the Fig. 11 and 12 shown. The stack arrangement S1 is formed, for example, by one of the first, second and third disk elements or by the first disk element 2, the second disk element 3 and the third disk element 4. Due to the different outer diameters DA2, DA3, DA4 and the specifically selected sequence of the disk elements 2, 3, 4 in the axial direction, the stack arrangement S1 has an outer contour A'. This is shown in Fig. 12 shown schematically in a highly simplified manner and conical in the broadest sense. In contrast, the bone implant 100 is formed by a different, further stacking arrangement S2 of disc elements of the bone implant system 1, which will be described in more detail later, and has the aforementioned outer contour A.

[0028] Depending on the selection and stacking sequence of the various disc elements 2 to 7 of the bone implant system 1, a wide variety of stacking arrangements and thus bone implants with a wide variety of outer contours can be formed. The disc elements in question are not simply placed loosely on top of one another, but are positively secured to one another in the radial and circumferential directions. For this purpose, the various disc elements 2 to 7 each have a positive-locking section 8 and a complementary positive-locking section 9 (see in particular Fig. 2 bis 10 ). The design and function of the form-locking sections 8 and the complementary form-locking sections 9 as well as the remaining design and function of the different disc elements 2 to 7 are explained below using the Fig. 2 bis 10 explained by way of example with regard to the first disc element 2, the second disc element 3 and the third disc element 4.

[0029] The first disc element 2 ( Fig. 2 bis 4 ) is circular in the embodiment shown and can therefore also be referred to as a circular ring element. Due to the annular design, the disk element 2 has an inner diameter DI. The inner diameter DI is formed by a central bore 10 which extends coaxially to a central longitudinal axis M2 of the first disk element 2. The (first) outer diameter DA2 is concentric to the inner diameter DI in the present case. The first disk element 2 has an axial thickness H2. In an embodiment not shown in the drawing, the disk elements are elliptical.

[0030] The form-fitting section 8 is on an upper side ( Fig. 2 ) of the first disc element 2. The complementary form-fitting section 9 is arranged on an axially opposite underside ( Fig. 4 ).

[0031] In the embodiment shown, the form-fitting section 8 has two connecting pins 11 arranged offset by 180° around the central longitudinal axis M2. The connecting pins 11 protrude axially from the upper side and have a circular-cylindrical solid cross-section.

[0032] In an embodiment not shown in the drawing, the form-fitting section can have only one connecting pin or more than the two connecting pins shown here.

[0033] The connecting pins 11 can be formed integrally on the top side of the first disc element 2 or manufactured as separate components and joined to the top side. In the embodiment shown, the connecting pins are separate components and are each inserted into unspecified receiving bores arranged on the top side of the first disc element 2. The complementary form-fitting section 9 has four receiving bores 12, each offset by 90° around the central longitudinal axis M2. The receiving bores 12 extend longitudinally parallel to the central longitudinal axis M2. The same applies to the connecting pins 11.

[0034] In an embodiment not shown in the drawing, the complementary form-fitting section 9 has fewer or more than the four receiving bores 12 shown here.

[0035] The connecting pins 12 are arranged on a bolt circle with a bolt circle diameter DL. The same applies to the connecting pins 11. The bolt circle diameter DL or the bolt circle is determined based on the Fig. 2 und 4 shown in dash-dotted lines.

[0036] In the embodiment shown, the bolt circle is concentric with respect to the central longitudinal axis M2. Concentricity is thus also present with respect to the inner diameter DI and the first outer diameter DA2.

[0037] Furthermore, the first disc element 2 in the present case has at least one spacer section 13 which protrudes in the axial direction from the upper side. In the present case, a total of four spacer sections 13 are provided and are each arranged in pairs adjacent to the connecting pins 11 in the region of the bolt circle diameter DL. In the embodiment shown, the spacer sections 13 have a square cross-section, which is to be understood as purely exemplary. The spacer sections 13 can be formed integrally on the upper side or connected to the upper side of the first disc element 2 as separate components. In the embodiment shown, the spacer sections 13 are each designed as separate spacer pins and are inserted into holes (not shown in detail) made in the upper side of the first disc element 2.

[0038] In an embodiment not shown in the drawing, the spacer sections are arranged on the underside. Furthermore, it is understood that the spacer sections do not necessarily have to be arranged in the area of the bolt circle diameter DL.

[0039] Furthermore, the first disc element 2 in this case has two receiving recesses 14 axially recessed into its upper side. The receiving recesses 14 can also be referred to as receiving pockets. The two receiving recesses 14 are offset from each other by 180° with respect to the central longitudinal axis M2 and each have a rectangular basic shape. Both the arrangement and the design of the receiving recesses are to be considered purely exemplary.

[0040] The second disc element 3 ( Fig. 5 bis 7 ) and the third disc element 4 ( Fig. 8 bis 10 ) are identical to the first disc element 2 with regard to the design and / or arrangement of the form-fitting section 8 and the complementary form-fitting section 9. Identical components and / or sections are accordingly assigned identical reference numerals. What has been said with regard to the form-fitting section 8 and the complementary form-fitting section 9 in connection with the first disc element 2 applies accordingly to the second disc element 3 and the third disc element 4 and, moreover, to all other disc elements of the bone implant system 1. The identical design and / or arrangement of the form-fitting sections and the complementary form-fitting sections ensures - to put it simply - that all disc elements of the bone implant system 1 can be secured to one another regardless of the respective stacking arrangement.

[0041] The design and arrangement of the spacer sections 13 are also identical. This is advantageous, but not mandatory. In an embodiment not shown, the spacer sections of the various disc elements 2 to 7 can be designed and / or arranged differently.

[0042] Further in accordance with the first disc element 2, the second disc element 3 also has receiving recesses 14 recessed into its upper side. The receiving recesses 14 of the second disc element 3 differ only in their size from the receiving recesses 14 of the first disc element 2, so a separate reference symbol is omitted. The same applies analogously to the third disc element 4 and its receiving recesses 14.

[0043] Furthermore, the second disc element 3 has an axial thickness H3. The third disc element 4 has an axial thickness H4. In the embodiment shown, the first, second, and third disc elements are of equal thickness, so that the thicknesses H2, H3, and H4 correspond. In an embodiment not shown in the drawing, different disc elements have different thicknesses. Furthermore, it is conceivable for disc elements with the same outer diameter to have different thicknesses. For example, within the first set of disc elements 2, 2', 2" and / or the remaining disc element sets of the bone implant system 1.

[0044] To train the Fig. 12 In the stacking arrangement S1 shown, the first disk element 2 or one of the first disk elements 2, 2', 2" is selected. In addition, the second disk element 3 and the third disk element 4 or one of the respective disk elements are selected. The second disk element 3 is aligned in the axial direction in alignment with the first disk element 2, so that the central longitudinal axes M2, M3 are aligned coaxially. In addition, the second disk element 3 is positioned in the circumferential direction relative to the first disk element 2 such that the connecting pins 11 of the latter can engage in the receiving bores 12 of the second disk element 3. The second disk element 3 is then pushed onto the first disk element 2 in the axial direction. As a result, a positive connection is formed both radially and in the circumferential direction between the connecting pins 11 and the receiving bores 12.Due to the spacer sections 13 arranged on the top side of the first disc element 2, a radial gap 15 extending in the axial direction is created. Fig. 12 ). The third disc element 4 is then stacked on the second disc element 3 with the central longitudinal axes M3, M4 coaxially aligned. This in turn creates a corresponding positive fit between the connecting pins 11 of the second disc element 3 and the receiving bores 12 of the third disc element 4. In addition, a radial gap 15 is also created between the second disc element 3 and the third disc element 4.

[0045] With regard to the Fig. 11 and 12 It is worth noting that both the connecting pins 11 and the spacer sections 13 of the third disc element 4 can be removed as separate components due to their respective designs. This is advantageous, but not mandatory.

[0046] In the stacking arrangement S1, the central bores 10 or the inner diameters DI form a cylindrical receiving recess Z. The receiving recess Z is suitable for receiving a shaft section GS of the joint replacement implant G ( Fig. 13 ).

[0047] The axial gaps 15 formed between the disc elements 2, 3, 4 allow the penetration and / or introduction of a connecting compound V (cf. Fig. 13 ). This allows the stacking arrangement S1 to be further stabilized. Alternatively or additionally, the connecting compound V can be introduced into the receiving recesses 14 of the disc elements 2, 3, 4 before they are stacked on top of one another.

[0048] Based on Fig. 14 An embodiment of a method according to the invention for producing the bone implant 100 using the bone implant system 1 is schematically illustrated. The method comprises steps a), b), and c).

[0049] In step a), the inner contour I of the metaphyseal bone defect D is first measured. Suitable measurement methods for this are generally known to those skilled in the art. For example, a so-called time-of-flight camera can be used.

[0050] Step b) provides for determining the outer contour A of the bone implant 100 required to fill the bone defect D. The outer contour A is determined as a function of the previously recorded inner contour I, preferably computer-aided and / or simulation-based.

[0051] Step c) involves selecting, stacking, and attaching several different disc elements of the bone implant system 1. The plurality of disc elements are selected and / or stacked depending on the determined outer contour A, preferably intraoperatively. The selection is carried out by medical personnel and preferably computer-assisted and / or simulation-based. In the present case, the first disc element 2, a second disc element 3, a third disc element 4, a fourth disc element 5, a fifth disc element 6, and a sixth disc element 7 are selected and stacked one on top of the other. The connection of said disc elements is achieved by means of the form-fitting sections 8 and the complementary form-fitting sections 9, as previously described. Fig. 13Individual disc elements 2 to 7 are shown with different thicknesses. This is to clarify once again that not all disc elements of the bone implant system 1 necessarily have to have the same axial thickness. After the disc elements 2 to 7 have been manually stacked on top of one another and secured to one another in a form-fitting manner, the bone implant 100 can be inserted into the bone defect D and anchored there using the connecting compound V, which in this case is a bone cement. The connecting compound V can be introduced into the cylindrical receiving recess Z or between the different disc elements 2 to 7 before the bone implant 100 is inserted. This provides additional stabilization of the bone implant 100. After the bone implant 100 has been anchored, the joint replacement implant G can be attached proximally to the tibia T.The shaft section GS is inserted axially into the cylindrical receiving recess Z and anchored therein in the radial direction.

Claims

1. Bone implant system (1) for producing an individualized bone implant (100), having a plurality of different disc elements (2 to 7) with different external diameters (DA2 to DA7), wherein the disc elements (2 to 7) are able to be stacked axially one on top of another in different combinations in order to form different stack arrangements (S1, S2), wherein the disc elements (2 to 7) each have a form-fitting portion (8) arranged on an upper face and a complementary form-fitting portion (9) arranged on an axially opposite lower face, by means of which the disc elements in the different stack arrangements (S1, S2) are able to be interlockingly fastened to one another in radial direction and / or circumferential direction, characterized in that the different stack arrangements (S1, S2) have different outer contours (A, A') on account of the different external diameters (DA2 to DA7) of the disc elements (2 to 7).

2. Bone implant system (1) as claimed in claim 1, characterized in that the disc elements (2 to 7) are each ring-shaped and have a, preferably identical, internal diameter (DI).

3. Bone implant system (1) as claimed in claim 1 or 2, characterized in that the disc elements (2 to 7) each have at least one spacer portion (13) protruding in the axial direction from the upper face or the lower face, as a result of which the disc elements (2 to 7) are able to be stacked one on top of another in the different stack arrangements (S1, S2) while forming axial gaps (15).

4. Bone implant system (1) as claimed in one of the preceding claims, characterized in that the disc elements (2 to 7) each have at least one receiving recess (14) which is sunk into the upper face or the lower face and which is provided for receiving a connecting compound (V).

5. Bone implant system (1) as claimed in one of the preceding claims, characterized in that the form-fitting portions (8) each have at least one axially protruding connection pin (11), and in that the complementary form-fitting portions (9) each have at least one receiving bore (12) introduced in the axial direction, or vice versa.

6. Bone implant system (1) as claimed in claim 5, characterized in that the disc elements (2 to 7) each have a plurality of connection pins (11) and / or receiving bores (12) arranged offset in the circumferential direction, the arrangements of the connection pins (11) and / or of the receiving bores (12) of the different disc elements (2 to 7) forming an identical bore pattern.

7. Bone implant system (1) as claimed in one of the preceding claims, characterized in that at least three, preferably more than six, particularly preferably more than twelve, different disc elements (2 to 7) are provided.

8. Bone implant (100) produced using a bone implant system (1) as claimed in one of claims 1 to 7, the bone implant (100) having a plurality of disc elements (2 to 7) stacked one on top of another in the axial direction with different external diameters (DA2 to DA7), the disc elements (2 to 7) stacked one on top of another being interlockingly fastened to one another in radial direction and / or circumferential direction by means of form-fitting portions (8) arranged on the upper face of the disc elements (2 to 7) and complementary form-fitting portions (9) arranged on the lower face of the disc elements (2 to 7).

9. Method for producing an individualized bone implant (100) according to claim 8, comprising the steps of: a) recording an inner contour (I) of a bone defect (D); b) determining an outer contour (A) of the bone implant (100), required to fill the bone defect (D), in accordance with the recorded inner contour (I); c) selecting, stacking and mutually fastening a plurality of different disc elements (2 to 7) of the bone implant system (1), the plurality of disc elements (2 to 7) being selected and / or stacked in accordance with the recorded outer contour (A).