WO2024161257A1

WO2024161257A1 - Endoprosthesis having improved primary stability and optimized revision properties

Info

Publication number: WO2024161257A1
Application number: PCT/IB2024/050720
Authority: WO
Inventors: Gabriel Tschupp; Stefan Saladin
Original assignee: Mathys Ag Bettlach
Priority date: 2023-01-31
Filing date: 2024-01-25
Publication date: 2024-08-08

Abstract

An endoprosthesis (11) is provided. The endoprosthesis (11) comprises at least one structure (12) for ensuring the primary stability of the endoprosthesis (11), wherein the at least one structure (12) at least partially comprises or consists of a material that can be resorbed by the human body. In addition, the at least one structure (12) is arranged on a non-metallic material, in particular on a plastic material.

Description

ENDOPROSTHESIS HAVING IMPROVED PRIMARY STABILITY AND OPTIMIZED REVISION PROPERTIES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to German Patent Application No. 10 2023 116 397.3 filed June 22, 2023 and German Utility Model Application No. 20 2023 100 431.8 filed on January 31, 2023, each of which is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The disclosure relates to an endoprosthesis having improved primary stability and optimized revision properties.

BACKGROUND

[0003] Due to the life expectancy of humans increasing and the associated increased likelihood or necessity of replacing at least a portion of at least one joint with a corresponding implant throughout someone’s life, there is a growing demand for joint replacement with improved properties, for example in the sense of improved primary stability and optimized properties within the context of a corresponding revision, in particular in order to ensure as high a quality of life as possible for the respective patients, even after a corresponding implantation or revision.

[0004] Publication WO 2009/108886 Al relates to a press-in prosthesis for replacing a portion of a bone. The prosthesis can comprise a first side and a second side opposite the first side. The second side can be operable in order to engage with the bone. The prosthesis can comprise at least one resorbable fastening element coupled to the second side. The at least one resorbable fastening element can be coupled offset from a center of the second side. The at least one resorbable fastening element can substantially resist movement of the prosthesis relative to the bone. The at least one resorbable fastening element can be resorbed at a rate that allows bone ingrowth in order to couple the prosthesis firmly to the bone. Furthermore, the at least one resorbable fastening element is fastened to a metallic bone engagement surface. In particular, due to a lack of flexibility of the metallic bone engagement surface, stress shielding of the corresponding bone occurs, which disadvantageously leads to degradation of the relevant bone. OBJECT AND ACHIEVEMENT

[0005] It is therefore an object of the disclosure to provide an endoprosthesis, wherein improved primary stability and optimized revision properties can be achieved particularly easily and cost-effectively.

[0006] The object is achieved with respect to the endoprosthesis by the features of claim 1. The dependent claims include advantageous developments.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0007] According to the disclosure, an endoprosthesis is provided. The endoprosthesis comprises at least one structure for ensuring the primary stability of the endoprosthesis, wherein the at least one structure at least partially comprises or consists of a material that can be resorbed by the human body. In addition, the at least one structure is arranged on a non- metallic material, in particular on a plastic material.

[0008] Advantageously, both improved primary stability and optimized revision properties are thus achieved in a particularly simple and cost-effective manner.

[0009] According to a first embodiment of the disclosure, the at least one structure completely comprises or consists of the material that can be resorbed by the human body.

[0010] Advantageously, the revision properties can thus, for example, be further improved.

[0011] According to a second embodiment of the disclosure, the at least one structure comprises at least one anchoring pin, in particular at least one peg, and/or at least one fin.

[0012] Advantageously, for example, the primary stability can thus be further improved.

[0013] According to a further embodiment of the disclosure, at least a portion of a surface of the endoprosthesis facing the corresponding bone and/or joint part, said surface being in particular free of the at least one structure, and/or the at least one structure comprises honeycomb structures, in particular honeycomb ribs, and/or corrugated structures, in particular corrugated ribs, and/or zigzag structures, in particular zigzag ribs, and/or tire-tread-like structures, in particular tire-tread-like ribs, and/or barb-like structures, in particular barbs, and/or bent anchoring pins, in particular bent pegs, and/or star-shaped anchoring pins, in particular star-shaped pegs, and/or tubular anchoring pins, in particular tubular pegs, and/or at least one anchoring pin having a thread, in particular at least one peg having a thread, and/or fins having thickened portions, in particular fins having thickened portions in the corresponding implantation direction, and/or fins having at least one hole and/or nub-like structures, in particular nubs, and/or cam-like structures, in particular cams, and/or polygonal structures, in particular polygon structures, and/or at least one screw and/or at least one nail. [0014] Advantageously, a corresponding shear force can thus, for example, be resorbed in all directions, in particular with the aid of the honeycomb structures.

[0015] With regard to the barb-like structures, in particular the barbs, it should be noted that these can also be hook-like structures, in particular hooks.

[0016] It should also be noted that it may be advantageous for the endoprosthesis additionally or alternatively to comprise an at least partially or completely resorbable H-carrier, which can in particular be pushed into the corresponding bone and/or joint part. Advantageously, very good fixing can thus be achieved, for example, which enables particularly rapid growth adhesion.

[0017] According to a further embodiment of the disclosure, at least a portion of a surface of the endoprosthesis facing the corresponding bone and/or joint part, said surface being in particular free of the at least one structure, and/or the at least one structure comprises a plurality of mandrels and/or prongs and/or spikes.

[0018] Advantageously, the endoprosthesis may be manufactured from a flexible material and/or biomaterials and/or artificial cartilage, in particular by means of the large-area or wholesurface connection.

[0019] According to a further embodiment of the disclosure, at least some, preferably each of the mandrels and/or prongs and/or spikes is designed like an arrow, preferably as an arrow, and/or like a nail, preferably as a nail, particularly preferably as a nail made of magnesium. [0020] The arrow may advantageously be designed in particular in the sense of a hook or barb. [0021] According to a further embodiment of the disclosure, the material that can be resorbed by the human body is magnesium and/or polylactide and/or polylactide-co-glycolide and/or polycaprolactone and/or polylactide-co-caprolactone and/or polyglycolide and/or polydioxanone.

[0022] Advantageously, the time required for corresponding resorption can thus, for example, be easily adjusted.

[0023] According to a further embodiment of the disclosure, the at least one structure comprises an at least partial, preferably complete coating with calcium.

[0024] Advantageously, the time required for corresponding resorption can thus, for example, be extended in a simple manner.

[0025] According to a further embodiment of the disclosure, the endoprosthesis, in particular a base material of the endoprosthesis, comprises and/or consists of plastic, preferably poly etherketone (PEK) and/or poly ether ether ketone (PEEK) and/or PEEEK and/or PEEKK and/or PEEEKK and/or PEKEKK and/or polyaryletherketone (PAEK) and/or polyethylene (PE) and/or cross-linked PE and/or ultra-high-molecular-weight polyethylene (UHMWPE) and/or cross-linked UHMWPE, and/or UHMWPE with vitamin E added, and/or polycarbonate urethane (PCU), and/or hydrogel, and/or metal, preferably titanium and/or tantalum, and/or an alloy, preferably cobalt-chromium-molybdenum (CoCrMo) and/or a titanium alloy, and/or ceramic, preferably aluminum-oxide-reinforced zirconium dioxide and/or aluminum oxide and/or zirconium-dioxide-reinforced aluminum oxide and/or silicon nitride, and/or artificial cartilage and/or human cartilage and/or animal cartilage, and/or wherein the endoprosthesis, in particular a base material of the endoprosthesis and/or at least a portion of the regions, which are free of the at least one structure, a coating enabling corresponding growth adhesion, preferably a coating with calcium phosphate and/or titanium and/or titanium particles.

[0026] Advantageously, the endoprosthesis may be at least partially or completely an allograft, autograft, xenograft or a synthetic implant.

[0027] According to a further embodiment of the disclosure, at least a portion of a surface which faces the corresponding bone and/or joint part, preferably the surface which faces the corresponding bone and/or joint part, of the endoprosthesis is designed to enable or facilitate growth adhesion to the corresponding bone and/or joint part, wherein said surface is in particular free of the at least one structure.

[0028] Advantageously, for example, cement-free anchoring may thus be achieved.

[0029] According to a further embodiment of the disclosure, at least the portion of the surface which faces the corresponding bone and/or joint part, preferably the surface which faces the corresponding bone and/or joint part, of the endoprosthesis comprises titanium and/or titanium particles and/or a titanium alloy, wherein said surface is in particular free of the at least one structure.

[0030] Advantageously, corresponding growth adhesion can thus, for example, be enabled or facilitated particularly efficiently.

[0031] According to a further embodiment of the disclosure, the at least one structure is designed to increase the stiffness of the endoprosthesis.

[0032] Advantageously, it can thus be achieved, for example, that the endoprosthesis first allows particularly good growth adhesion and, in subsequent development, allows physiological stress on the bone due to correspondingly increasing flexibility.

[0033] According to a further embodiment of the disclosure, the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis facing the corresponding bone and/or joint part, said surface being in particular free of the at least one structure, and/or of the at least one structure is determined as a function of the bone density and/or stress, in particular pressure and/or shear stress in each case, of the corresponding bone and/or joint part. [0034] Advantageously, for example, the corresponding stress gradient and/or the corresponding bone quality can thus be taken into account in the design of the structures in a particularly efficient manner.

[0035] According to a further embodiment of the disclosure, the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis facing the corresponding bone and/or joint part, said surface being in particular free of the at least one structure, and/or of the at least one structure is determined according to the following formula:

1

G ~ a + b * B * ~

D where G is the size of the corresponding structures, where a is a first constant, where b is a second constant, where B is the stress, in particular pressure and/or shear stress, of the corresponding bone and/or joint part, and where D is the bone density of the corresponding bone and/or joint part.

[0036] Advantageously, for example, the use of a finite-element method can thus be dispensed with, which not only simplifies the production of the endoprosthesis, but also lowers the corresponding production costs.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] In the following, a detailed exemplary description of some embodiments of the disclosure is given with reference to the figures of the drawings. In the drawings:

Fig. 1 shows an exemplary embodiment of an implant, in particular of a tibia implant, with resorbable pegs within the meaning of the disclosure;

Fig. 2 shows exemplary honeycomb ribs, in particular for the large-area anchoring of the corresponding implant within the meaning of the disclosure;

Fig. 3 shows exemplary structures as a function of stress and bone quality in the context of the large-area anchoring within the meaning of the disclosure; and

Fig. 4 shows an exemplary structure within the meaning of the disclosure, by means of which in particular a high stiffness of the endoprosthesis in a corresponding main stress direction is achieved. [0038] Before the aforementioned figures are explained in detail, it should be noted that the corresponding bone interface of an endoprosthesis within the meaning of the disclosure, for example a joint endoprosthesis, may consist of two parts. The surface facing the corresponding bone and/or joint part preferably consists of a material onto which the bone can grow.

[0039] Structures, for example pegs, fins, or the like, provide the desired stability at the beginning, in particular by means of a press fit, so that the surface facing the corresponding bone and/or joint part may grow thereupon.

[0040] Said structures preferably consist at least partially of a material, for example magnesium, which can be resorbed by the human body. The material is advantageously to be designed such that, for example, the pegs or correspondingly other structures still provide sufficient press fit during the growth adhesion, but are almost fully degraded or completely degraded at the time of explantation.

[0041] According to Fig. 1, the endoprosthesis 11 comprises at least one structure 12 for ensuring the primary stability of the endoprosthesis 11, wherein the at least one structure 12 at least partially comprises or consists of a material that can be resorbed by the human body. In addition, the at least one structure 12 is arranged on a non-metallic material, in particular on a plastic material.

[0042] The at least one structure 12 does not necessarily have to be arranged on or attached directly to the non-metallic material, in particular to the plastic material.

[0043] The endoprosthesis shown by way of example in Fig. 1 may in particular be a tibia endoprosthesis. According to the example, the at least one structure 12 is designed as a resorbable anchoring structure, in particular as a resorbable peg.

[0044] It may be advantageous for the at least one structure 12 to completely comprise or consist of the material that can be resorbed by the human body.

[0045] In addition or as an alternative to the aforementioned pegs or anchoring pins, the at least one structure 12 may comprise at least one fin.

[0046] In addition or in the alternative, the at least one structure 12 may comprise an at least partial, preferably complete, coating with calcium.

[0047] Furthermore, it may be advantageous for the at least one structure 12 to be designed to increase the stiffness of the endoprosthesis 11.

[0048] It should be noted in relation to the material that can be resorbed by the human body that it may be advantageous for the material that can be resorbed by the human body to comprise or be magnesium and/or polylactide and/or polylactide-co-glycolide and/or polycaprolactone and/or polylactide-co-caprolactone and/or polyglycolide and/or polydioxanone.

[0049] It may furthermore be advantageous for the endoprosthesis 11, in particular a base material of the endoprosthesis 11 and/or the non-metallic material, to comprise and/or consist of plastic, preferably polyetherketone (PEK) and/or polyether ether ketone (PEEK) and/or PEEEK and/or PEEKK and/or PEEEKK and/or PEKEKK and/or polyaryletherketone (PAEK) and/or polyethylene (PE) and/or cross-linked PE and/or ultra-high-molecular-weight polyethylene (UHMWPE) and/or cross-linked UHMWPE, and/or UHMWPE with vitamin E added, and/or polycarbonate urethane (PCU), and/or hydrogel, and/or metal, preferably titanium and/or tantalum, and/or an alloy, preferably cobalt-chromium-molybdenum (CoCrMo) and/or a titanium alloy, and/or ceramic, preferably aluminum-oxide-reinforced zirconium dioxide and/or aluminum oxide and/or zirconium-dioxide-reinforced aluminum oxide and/or silicon nitride, and/or artificial cartilage and/or human cartilage and/or animal cartilage.

[0050] In addition or in the alternative, the endoprosthesis 11, in particular a base material of the endoprosthesis 11 and/or the non-metallic material and/or at least a portion of the regions, which are free of the at least one structure 12, may comprise a coating enabling corresponding growth adhesion, preferably a coating with calcium phosphate and/or titanium and/or titanium particles.

[0051] It should also be noted that the corresponding bone 13 is also shown in Fig. 1. It may be advantageous for at least a portion of a surface which faces the corresponding bone 13 and/or joint part, preferably the surface which faces the corresponding bone 13 and/or joint part, of the endoprosthesis 11 to be designed to enable or facilitate growth adhesion to the corresponding bone 13 and/or joint part, wherein said surface is in particular free of the at least one structure 12.

[0052] In addition or in the alternative, at least the portion of the surface which faces the corresponding bone 13 and/or joint part, preferably the surface which faces the corresponding bone 13 and/or joint part, of the endoprosthesis 11 may comprise titanium and/or titanium particles and/or a titanium alloy, wherein said surface is in particular free of the at least one structure 12.

[0053] The at least one structure 12 shown correspondingly in Fig. 1 may also be based on or at least partially made of or be a macrostructure, which is described in more detail below with reference to Fig. 2, Fig. 3 and Fig. 4. [0054] In this context, it should be noted that the terms “the at least one structure” and “the macrostructure” that are used within the scope of the present disclosure may in particular be understood as synonyms.

[0055] In particular, as an alternative understanding, it may also apply that at least a portion of a surface of the endoprosthesis facing the corresponding bone and/or joint part is free of the at least one structure, and/or the at least one structure comprises the macrostructure.

[0056] The disclosure advantageously minimizes the corresponding bone loss during a revision. A further advantage also results: There is more design scope, in particular since the shape of macrostructures does not have to take a possible revision into account.

[0057] Within the meaning of the disclosure, an efficient option for achieving or improving primary stability for endoprostheses is provided in synergy with the optimized revision properties. The endoprosthesis according to the disclosure makes it possible, in particular, for the endoprosthesis to connect to the bone in a form-fitting manner, preferably over the entire surface of the endoprosthesis.

[0058] Advantageously, the disclosure is independent of the corresponding shape of the endoprosthesis. For example, this can relate to the anterior and/or posterior surface of a femur endoprosthesis or also other endoprostheses. In addition, there is an independence of spot connections, such as pegs, fins, or the like.

[0059] The corresponding anchoring of the endoprosthesis is advantageously created via a macro-structured surface of the endoprosthesis. It should be noted that the corresponding bone may likewise be provided with a macrostructure, which preferably generates a very large number of anchoring points.

[0060] The macro-structured surface or macrostructure used in particular for anchoring or large-surface anchoring may preferably have honeycomb ribs 20 according to Fig. 2. Advantageously, this shape results in a corresponding shear force being able to be resorbed in all directions, which is illustrated by way of example with the aid of reference signs 21, 22, 23 in Fig. 2.

[0061] Advantageously, the macrostructure has an edge steepness of at least 70 degrees.

[0062] In addition or as an alternative to the honeycomb ribs 10, the macrostructure may comprise corrugated structures, in particular corrugated ribs, and/or zigzag structures, in particular zigzag ribs, and/or tire-tread-like structures, in particular tire-tread-like ribs, and/or barb-like structures, in particular barbs, and/or bent anchoring pins, in particular bent pegs, and/or star-shaped anchoring pins, in particular star-shaped pegs, and/or tubular anchoring pins, in particular tubular pegs, and/or at least one anchoring pin having a thread, in particular at least one peg having a thread, and/or fins having thickened portions, in particular fins having thickened portions in the corresponding implantation direction, and/or fins having at least one hole and/or nub-like structures, in particular nubs, and/or cam-like structures, in particular cams, and/or polygonal structures, in particular polygon structures, and/or at least one screw and/or at least one nail.

[0063] An additional or alternative option consists of many individual points which are so close to one another that a quasi full-surface connection is also produced. These individual points may be many small spikes, for example having approximately 1.5 mm diameter and/or approximately 6 mm height or length.

[0064] In addition or as an alternative to the spikes, the macrostructure may comprise a plurality of mandrels and/or prongs.

[0065] It may be particularly advantageous for at least some, preferably each, of the mandrels and/or prongs and/or spikes to be designed like an arrow or as an arrow, in particular in the sense of a barb.

[0066] In addition or in the alternative, at least some, preferably each of the mandrels and/or prongs and/or spikes, may be designed like a nail, preferably as a nail, particularly preferably as a nail made of magnesium.

[0067] Furthermore, it may be particularly advantageous for at least some, preferably each of the mandrels and/or prongs and/or spikes to have such a corresponding diameter/length ratio, so that, although they can dissolve relatively quickly, they do not break or bend during the corresponding implantation. In this context, the values for diameter and length already indicated above are particularly advantageous.

[0068] In principle, it is advantageous for at least a portion, preferably each of the mandrels and/or prongs and/or spikes to have a length between 4 mm and 8 mm, preferably between 5 mm and 7 mm, particularly preferably between 5.5 mm and 6.5 mm.

[0069] In addition or in the alternative, it is in principle advantageous for at least some, preferably each of the mandrels and/or prongs and/or spikes to have a diameter between 0.5 mm and 2.5 mm, preferably between 1 mm and 2 mm, particularly preferably between 1.3 mm and 1.7 mm.

[0070] It should also be noted that at least a portion, preferably each of the mandrels and/or prongs and/or spikes, may comprise or consist of magnesium and/or titanium.

[0071] Preferably, mandrels and/or prongs and/or spikes which comprise more magnesium than titanium have a larger diameter than mandrels and/or prongs and/or spikes which comprise less magnesium than titanium. [0072] It should also be noted that the stress on the bone may be different over the course of the corresponding surface. The expected bone stiffness may likewise vary on the corresponding bone interface. This situation is illustrated with reference to Fig. 3. Here, the curve with reference sign 31 illustrates the corresponding bone density, while the curve with reference sign 32 relates to the corresponding stress.

[0073] This stress gradient and the bone quality may be incorporated into the design of the structures, which can be seen from the macrostructure or the anchoring structures 34 in Fig. 3. Thus, preferably at locations at which large stresses are expected and/or the bone quality is less good, the structures may be designed to be larger and/or deeper than in regions with small or smaller stress and good or better bone quality. In addition, both the corresponding endoprosthesis 33 and the corresponding bone 35 are shown in Fig. 3.

[0074] Accordingly, it may be advantageous for the size of the corresponding structures of the macrostructure 34 to be determined in each case as a function of the bone density 31 and/or stress 32, in particular pressure and/or shear stress, of the corresponding bone 35.

[0075] In other words, it may be particularly advantageous for the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis 33 facing the corresponding bone 35 and/or joint part, said surface being in particular free of the at least one structure, and/or of the at least one structure to be determined in each case as a function of the bone density 31 and/or stress 32, in particular pressure and/or shear stress, of the corresponding bone 35 and/or joint part.

[0076] In this context, it may be particularly advantageous for the size of the corresponding structures of the macrostructure 34 to be determined according to the following formula:

G ~ a + b * B * ~ D where G is the size of the corresponding structures or of the corresponding structures of the macrostructure 34, where a is a first constant, where b is a second constant, where B is the stress, in particular pressure and/or shear stress, of the corresponding bone 35, and where D is the bone density of the corresponding bone 35.

[0077] In other words, it may be particularly advantageous for the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis 33 facing the corresponding bone 35 and/or joint part, said surface being in particular free of the at least one structure, and/or of the at least one structure to be determined according to the above formula. [0078] It can also be seen from Fig. 3 that the macrostructure 34 has an edge steepness of 90 degrees. For example, the edge steepness is an edge steepness relative to a plane, in particular relative to a horizontal plane.

[0079] It should be noted that it may be advantageous for the surface facing the corresponding bone 35 to comprise at least 30 percent, preferably at least 50 percent, particularly preferably at least at least 80 percent, very particularly preferably 100 percent, of the macrostructure 34. In this case, the surface facing the corresponding bone 35 is in particular a contact surface in relation to the corresponding bone 35.

[0080] Preferably, this contact surface may be designed such that it is free of additional anchoring elements, for example pegs and/or fins. As already indicated above, the endoprosthesis within the meaning of the disclosure may advantageously be connected to the bone over the entire surface.

[0081] In particular due to the whole-surface connection, the endoprosthesis may be manufactured within the meaning of the disclosure from a flexible material, for example plastic, such as PMMA and/or artificial cartilage. The use of biomaterials which are specifically structured is also conceivable.

[0082] Accordingly, it may be particularly advantageous for the endoprosthesis, in particular a base material of the endoprosthesis, to comprise or consist of a flexible material and/or biomaterial. It may be advantageous here for the flexible material and/or the biomaterial to have in particular a thickness between 0.5 mm and 8 mm, preferably between 0.9 mm and 6 mm, particularly preferably between 1 mm and 5 mm, very particularly preferably between 1.5 mm and 2.5 mm.

[0083] A further advantage is in particular that, by using an endoprosthesis within the meaning of the disclosure, the strength is generated substantially by the corresponding bone and very thin and flexible endoprostheses are thus possible. Especially in endoprostheses for the early treatment of a local defect, it is important that they can later be revised with a conventional endoprosthesis. For this purpose, the tissue damage must be kept to a minimum.

[0084] Furthermore, it should be noted that the endoprosthesis within the meaning of the disclosure may also comprise or consist of human cartilage. In this context, for example, a piece of cartilage may preferably be removed by means of a laser at a location of the human body at which it is in particular not required, and, in particular after the cartilage is provided with the macrostructure, may preferably be inserted with the aid of a laser at the correspondingly desired location.

[0085] Finally, Fig. 4 illustrates an exemplary macrostructure 41 within the meaning of the disclosure, by means of which in particular a high stiffness of the endoprosthesis is achieved in a corresponding main stress direction. As already mentioned, the corresponding bone may likewise be provided with a macrostructure which preferably generates a very large number of anchoring points.

[0086] This is the case according to Fig. 4: The corresponding bone is also provided with a macrostructure 42 which interacts with the macrostructure 41 of the endoprosthesis, in particular in such a way that the endoprosthesis may be inserted in a corresponding lateral force direction. Advantageously, the endoprosthesis is very stiff in a corresponding main stress direction. For example, lifting of the endoprosthesis in the corresponding edge regions may thus be reliably avoided.

[0087] Fig. 4 also shows the insertion of the endoprosthesis into the corresponding auxiliary force direction in three steps. In a first step 1, the macrostructure 41 of the endoprosthesis is brought into position with respect to the macrostructure 42 of the bone. According to a second step 2, the endoprosthesis is now moved until it is brought completely into contact with the bone in a third step 3 or until the two macrostructures 41, 42, which are in particular designed to be complementary to one another, interlock.

[0088] It should be noted that the macrostructure 41 may, in particular, be seen as a section or as a representative of a two-dimensionally extended macrostructure. In other words, the corresponding endoprosthesis may in particular comprise a plurality of such macrostructures according to Fig. 4.

[0089] It should also be noted that the macrostructure 41 or the part of a two-dimensionally extended macrostructure in particular comprises an arrow-like or roof-like notch or depression, preferably an arrow-like or roof-like notch or depression, wherein the corresponding arrow head or the corresponding roof is equilateral.

[0090] Compared to the rest of the corresponding arrow head or roof, the tip of the corresponding arrow head or roof is preferably situated most deeply in the material of the endoprosthesis.

[0091] Furthermore, the macrostructure 41 or the part of a two-dimensionally extended macrostructure in particular has a trapezoidal notch or depression, preferably a trapezoidal notch or depression, wherein the corresponding trapezoid is equilateral. [0092] Compared to the rest of the corresponding trapezoid, the base, i.e. the longer of the two base sides of the corresponding trapezoid, is preferably situated most deeply in the material of the endoprosthesis.

[0093] Further preferably, the trapezoidal notch or depression is arranged offset by approximately 90 degrees, in particular 90 degrees, with respect to the arrow-like or roof-like notch or depression.

[0094] In addition, it should be noted that the two macrostructures 41 and 42 may in particular be interchanged. In other words, the macrostructure 42 may be that of the endoprosthesis, whereas the macrostructure 41 may be that of the bone.

[0095] The disclosure is not limited to the exemplary embodiments discussed above. All features described in the description or features claimed in the claims or features shown in the drawing can be combined with one another in any way within the scope of this disclosure.

Claims

1. An endoprosthesi s ( 11 , 33 ), wherein the endoprosthesis (11, 33) has at least one structure (12, 34) for ensuring the primary stability of the endoprosthesis (11, 33), wherein the at least one structure (12, 34) at least partially comprises or consists of a material that can be resorbed by the human body, and wherein the at least one structure (12, 34) is arranged on a non-metallic material, in particular on a plastic material.

2. The endoprosthesis (11, 33) according to claim 1, wherein the at least one structure (12, 34) completely comprises or consists of the material that can be resorbed by the human body.

3. The endoprosthesis (11, 33) according to claim 1 or 2, wherein the at least one structure (12, 34) comprises at least one anchoring pin, in particular at least one peg, and/or at least one fin.

4. The endoprosthesis (11, 33) according to any of claims 1 to 3, wherein at least a portion of a surface of the endoprosthesis (11, 33) facing the corresponding bone (13, 35) and/or joint part, said surface being in particular free of the at least one structure (12, 34), and/or the at least one structure (12, 34) comprises honeycomb structures, in particular honeycomb ribs (20), and/or corrugated structures, in particular corrugated ribs, and/or zigzag structures, in particular zigzag ribs, and/or tire-tread-like structures, in particular tire-tread-like ribs, and/or barb-like structures, in particular barbs, and/or bent anchoring pins, in particular bent pegs, and/or star-shaped anchoring pins, in particular star-shaped pegs, and/or tubular anchoring pins, in particular tubular pegs, and/or at least one anchoring pin having a thread, in particular at least one peg having a thread, and/or fins having thickened portions, in particular fins having thickened portions in the corresponding implantation direction, and/or fins having at least one hole and/or nub-like structures, in particular nubs, and/or cam-like structures, in particular cams, and/or polygonal structures, in particular polygon structures, and/or at least one screw and/or at least one nail.

5. The endoprosthesis (11, 33) according to any of claims 1 to 4, wherein at least a portion of a surface of the endoprosthesis (11, 33) facing the corresponding bone (13, 35) and/or joint part, said surface being in particular free of the at least one structure (12, 34), and/or the at least one structure (12, 34) comprises a plurality of mandrels and/or prongs and/or spikes.

6. The endoprosthesis (11, 33) according to claim 5, wherein at least some, preferably each of the mandrels and/or prongs and/or spikes is designed like an arrow, preferably as an arrow, and/or like a nail, preferably as a nail, particularly preferably as a nail made of magnesium.

7. The endoprosthesis (11, 33) according to any of claims 1 to 6, wherein the material that can be resorbed by the human body comprises or is magnesium and/or polylactide and/or polylactide-co-glycolide and/or polycaprolactone and/or polylactide-co-caprolactone and/or polyglycolide and/or polydioxanone.

8. The endoprosthesis (11, 33) according to any of claims 1 to 7, wherein the at least one structure (12, 34) comprises an at least partial, preferably complete, coating with calcium.

9. The endoprosthesis (11, 33) according to any of claims 1 to 8, wherein the endoprosthesis (11, 33), in particular a base material of the endoprosthesis (11, 33), comprises and/or consists of plastic, preferably polyetherketone (PEK) and/or poly ether ether ketone (PEEK) and/or PEEEK and/or PEEKK and/or PEEEKK and/or PEKEKK and/or polyaryletherketone (PAEK) and/or polyethylene (PE) and/or cross-linked PE and/or ultra-high-molecular-weight polyethylene (UHMWPE) and/or cross-linked UHMWPE, and/or UHMWPE with vitamin E added, and/or polycarbonate urethane (PCU), and/or hydrogel, and/or metal, preferably titanium and/or tantalum, and/or an alloy, preferably cobalt- chromium-molybdenum (CoCrMo) and/or a titanium alloy, and/or ceramic, preferably aluminum-oxide-reinforced zirconium dioxide and/or aluminum oxide and/or zirconium- dioxide-reinforced aluminum oxide and/or silicon nitride, and/or artificial cartilage and/or human cartilage and/or animal cartilage, and/or wherein the endoprosthesis (11, 33), in particular a base material of the endoprosthesis (11, 33) and/or at least a portion of the regions which are free of the at least one structure (12, 34), comprises a coating enabling corresponding growth adhesion, preferably a coating with calcium phosphate and/or titanium and/or titanium particles.

10. The endoprosthesis (11, 33) according to any of claims 1 to 9, wherein at least a portion of a surface which faces the corresponding bone (13, 35) and/or joint part, preferably the surface which faces the corresponding bone (13, 35) and/or joint part, of the endoprosthesis (11, 33) is designed to enable or facilitate growth adhesion to the corresponding bone (13, 35) and/or joint part, wherein said surface is in particular free of the at least one structure (12, 34).

11. The endoprosthesis (11, 33) according to any of claims 1 to 9, wherein at least the portion of the surface which faces the corresponding bone (13, 35) and/or joint part, preferably the surface which faces the corresponding bone (13, 35) and/or joint part, of the endoprosthesis (11, 33) comprises titanium and/or titanium particles and/or a titanium alloy, wherein said surface is in particular free of the at least one structure (12, 34).

12. The endoprosthesis (11, 33) according to any of claims 1 to 11, wherein the at least one structure (12, 34) is designed to increase the stiffness of the endoprosthesis (11, 33).

13. The endoprosthesis (11, 33) according to any of claims 1 to 12, wherein the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis (11, 33) facing the corresponding bone (13, 35) and/or joint part, said surface being in particular free of the at least one structure (12, 34), and/or of the at least one structure (12, 34) is determined in each case as a function of the bone density and/or stress, in particular pressure and/or shear stress, of the corresponding bone (13, 35) and/or joint part.

14. The endoprosthesis (11, 33) according to claim 13, wherein the size of the corresponding structures of the at least one portion of a surface of the endoprosthesis (11, 33) facing the corresponding bone (13, 35) and/or joint part, said surface being in particular free of the at least one structure (12, 34), and/or of the at least one structure (12, 34) is determined according to the following formula:

G ~ a + b * B * -

D where G is the size of the corresponding structures, where a is a first constant, where b is a second constant, where B is the stress, in particular pressure and/or shear stress, of the corresponding bone (13, 35) and/or joint part, and where D is the bone density of the corresponding bone (13, 35) and/or joint part.