BONE IMPLANT

Description

[0001] The invention relates to a bone implant, in particular for the treatment or care of bone defects and / or for anchoring or fixing a joint implant, preferably a knee joint implant.

[0002] In general, complex bone defects pose a significant challenge during revision joint surgery. This is especially true for the treatment or management of complex tibial or femoral bone defects. The treatment or management of such bone defects is further complicated by the fact that the shape and / or geometry of the tibia (shinbone) and femur (thigh bone) is subject to natural variation depending on a patient's height, gender, and ethnic origin.

[0003] In the treatment of complex joint bone defects, two primary goals are usually pursued: stable anchorage of a bone implant used for the treatment or restoration of the bone defect in a bony bed with high primary stability and reconstruction of the original biomechanical axes.

[0004] Conventional implants generally have the disadvantage that they only partially replicate the morphological conditions, particularly the shape and / or geometry and / or size, of bone defects, especially tibial or femoral bone defects. One consequence of this is that the shape and / or geometry and / or size of the bone defect must be adapted to the respective implant in order to achieve optimal cortical support. The associated (additional) bone loss, in turn, creates unfavorable starting conditions with regard to any necessary revision surgeries.

[0005] US 2007 / 118229 A1 discloses such a bone implant, which comprises a base body in the form of a hollow body open on both sides in the axial direction, comprising or consisting of a load-bearing material, and a casing body that at least partially surrounds the base body on the outside, or a plurality of shaped bodies that protrude radially from the base body. The casing body or the shaped bodies comprise an in vivo degradable / in vivo resorbable material.

[0006] The object of the invention is to provide a bone implant that partially or completely avoids the disadvantages described above in connection with conventional bone implants. In particular, the bone implant is intended to enable bone-sparing treatment or repair of bone defects and reduce the risk of revision surgery.

[0007] This object is achieved by a bone implant having the features according to independent claim 1 and by a method according to claim 14. Preferred embodiments of the invention are the subject of dependent claims 2 to 13 and the present description.

[0008] According to a first aspect, the invention relates to a bone implant, preferably for the treatment or care of bone defects, in particular tibial and / or femoral bone defects, and / or for the fixation or anchoring of a joint implant, in particular a knee joint implant.

[0009] The bone implant has the following: a base body in the form of a hollow body open on both sides in the axial direction, comprising or consisting of a load-bearing material, and a casing body which surrounds the base or hollow body on the outside, ieon an outer surface of the base or hollow body, at least partially, in particular only partially or completely, encased and comprising an in vivo degradable / in vivo resorbable material or consisting of an in vivo degradable / in vivo resorbable material, or a plurality of shaped bodies which protrude in a radial direction from the base or hollow body and comprise an in vivo degradable / in vivo resorbable material or consist of an in vivo degradable / in vivo resorbable material, wherein the encasing body or the shaped bodies each comprise at least two different in vivo degradable / in vivo resorbable materials which differ from one another with regard to their in vivo degradation rate / in vivo resorption rate. This (likewise) enables additional temporal control of the mechanical stability of the bone implant and of a biological reconstruction of a bone defect.In particular, this allows the mechanical stability of the bone implant, bone stimulation and bone growth to be coordinated even better.

[0010] For the purposes of the present invention, the term "bone implant" is to be understood as an implant for treating or treating a bone defect, in particular a tibial or femoral bone defect, and / or for fixing or anchoring a joint implant, in particular a knee joint implant.

[0011] For the purposes of the present invention, the term "shaped body" is to be understood as meaning bodies or components of the bone implant which are designed to effect fixation, anchoring or support of the basic or hollow body at / in a bone defect, in particular at / in a tibial or femoral bone defect.

[0012] For the purposes of the present invention, the expression "multiplicity of shaped bodies" is to be understood as meaning at least two, in particular more than two, shaped bodies, for example two, three, four, five, six, seven, eight, nine, ten or more shaped bodies.

[0013] For the purposes of the present invention, the term "bone defect" refers to a bone area affected by loss or damage to bone tissue, particularly joint bone tissue, preferably knee or hip joint bone tissue. The bone loss or bone damage may be the result of a bone fracture, bone trauma, necrosis, thinning (for example, due to osteoporosis), a bone disease such as tumor disease, a lack of mechanical loading (so-called stress shielding), or the result of a surgical intervention / reintervention, particularly a revision, preferably after a total knee or hip joint replacement.

[0014] The term "in vivo degradable / in vivo resorbable" means in vivo degradable or in vivo resorbable in the sense of the present invention.

[0015] The term "not in vivo degradable / not in vivo resorbable" means in the sense of the present invention not in vivo degradable or not in vivo resorbable.

[0016] The term "vivo degradation rate / in vivo absorption rate" means in vivo degradation rate or in vivo absorption rate in the context of the present invention.

[0017] For the purposes of the present invention, the term "load-bearing material" is to be understood as a material which is capable of withstanding forces normally occurring in a bone, such as in particular the tibia and / or femur, without or without significant deformation or destruction.

[0018] For the purposes of the present invention, the term "in vivo degradable material" refers to a material that can be metabolized in a human or animal body, particularly under the action of enzymes. The degradation of the material can proceed completely to mineralization, i.e., the release of chemical elements and their incorporation into inorganic compounds, such as carbon dioxide and / or oxygen and / or ammonia, or it can remain at the stage of degradation-stable intermediate or transformation products.

[0019] For the purposes of the present invention, the term "in vivo absorbable material" is understood to mean a material which can be absorbed into a human or animal body by living cells or living tissue, such as kidneys, without any degradation or significant degradation of the material taking place.

[0020] For the purposes of the present invention, the term "animal body" is understood to mean the body of a non-human mammal, such as a horse, cow, goat, sheep, pig or a rodent, such as a rabbit, rat or mouse.

[0021] The expression "in the axial direction" in the sense of the present invention is intended to mean along an axis, in particular the axis of symmetry, of a component or a body, such as the base or hollow body and / or the sheathing body, of the bone implant.

[0022] For the purposes of the present invention, the term "longitudinal axis" is to be understood as an axis of a component or a body, such as the base or hollow body and / or the sheathing body, of the bone implant, which corresponds to the direction of the greatest extension of the component or the body, such as the base or hollow body and / or the sheathing body.

[0023] The expression "in the radial direction" in the sense of the present invention is intended to mean pointing away from a point of symmetry, in particular the center point, and / or an axis of symmetry, in particular the central axis, of a component or a body, such as the base or hollow body and / or the sheathing body, of the bone implant.

[0024] The term "proximal" in the context of the present invention means pointing towards the center of the body or located closer to the center of the body.

[0025] The term "distal" in the context of the present invention shall mean pointing away from the center of the body or located away from the center of the body.

[0026] The term "conical hollow body" is to be understood in the context of the present invention as a hollow body which has a shell or a shell surface, wherein the shell or the shell surface is inclined at least in sections, in particular only in sections or completely, with respect to an axis of symmetry, in particular the central axis, of the hollow body.

[0027] The invention is characterized in particular by the following advantages: The load-bearing material of the base or hollow body makes it particularly advantageous to achieve primary and secondary stability that is medically sufficient. Primary stability is generally understood to mean the fixation of an implant based on friction or fastening elements, such as bone screws, in the first few weeks after surgery. Secondary stability is understood to mean the fixation of an implant based on bony adhesions. Secondary stability usually begins approximately one month after surgery and can last for up to several years. Furthermore, the in vivo degradable / in vivo resorbable material of the casing body or the shaped body advantageously allows for biological reconstruction of a bone defect and thus a reduction in the size of the bone defect. This can, in particular, create improved starting conditions for any revision surgeries. Another advantage is that the selection of the in vivo degradable / in vivo resorbable material of the casing body or the shaped body allows for targeted control of the mechanical stability of the bone implant and targeted influence on bone stimulation and bone growth. In particular, this allows the mechanical stability of the bone implant, bone stimulation, and bone growth to be coordinated with one another. The bone implant according to the present invention is particularly suitable for the treatment and / or restoration of tibial and / or femoral bone defects..

[0028] In an embodiment of the invention, the base or hollow body has a cornerless, in particular circular, oval or elliptical, cross-section.

[0029] In a further embodiment of the invention, the base or hollow body is conical. A conical base or hollow body has the particular advantage of enabling more stable anchoring of an extension shaft of a joint implant. Preferably, the base or hollow body has a tapered cross-sectional area in the axial or longitudinal direction, in particular a continuously or discontinuously tapered one, and / or a tapered inner diameter, in particular a continuously or discontinuously tapered one.

[0030] Alternatively, the base or hollow body can have a constant cross-sectional area and / or a constant inner diameter in the axial direction or longitudinal direction, in particular continuously.

[0031] The base or hollow body can, in principle, have a constant (i.e., uniform) or a varying (i.e., uneven) wall thickness, particularly in the axial or longitudinal direction. This makes it particularly advantageous to accommodate asymmetrically formed bone defects.

[0032] In a further embodiment of the invention, the base or hollow body has a wall thickness of 1 mm to 30 mm, in particular 5 mm to 20 mm, preferably 8 mm to 15 mm.

[0033] Furthermore, the base or hollow body can have a constant, i.e., uniform, or a varying, i.e., irregular, shape, particularly in the axial or longitudinal direction. This makes it particularly advantageous to accommodate (equally) asymmetrical bone defects.

[0034] Furthermore, the base or hollow body can have a wall with a number of openings or recesses in the axial direction, in particular in the longitudinal direction, i.e., only one opening / recess or a plurality of openings / recesses. The opening / recess or openings / recesses can be U-shaped, in particular. Preferably, the wall of the base or hollow body has two openings / recesses, in particular two openings / recesses arranged opposite one another. This allows a knee joint implant to be positioned in the base or hollow body with particular advantage. Tibial components of knee joint implants have medio-laterally attached "wings" to ensure stable anchoring and rotational stability.

[0035] In a further embodiment of the invention, the load-bearing material of the base or hollow body is a material that is non-degradable / non-resorbable in vivo. This advantageously enables particularly effective primary and secondary stability of the bone implant.

[0036] The in vivo non-degradable / in vivo non-resorbable material is preferably selected from the group consisting of metals, alloys, ceramics, plastics and combinations, in particular mixtures, thereof.

[0037] The metal can be selected, in particular, from the group consisting of tantalum, titanium, iron, zirconium, niobium, gold, and platinum. Titanium is particularly preferred.

[0038] The alloy can be selected, in particular, from the group consisting of magnesium alloy, tantalum alloy, titanium alloy, chromium-cobalt alloy, chromium-cobalt-molybdenum alloy, iron alloy, steel such as stainless steel, zirconium alloy, niobium alloy, gold alloy, platinum alloy, and combinations, especially mixtures, thereof. A titanium alloy, in particular Ti-6Al-4V, is particularly preferred.

[0039] The plastic can in particular be selected from the group consisting of polyether ketones, polyolefins, polyesters, polyamides, copolymers and combinations, in particular mixtures (blends), thereof.

[0040] The polyether ketones can be selected in particular from the group consisting of polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ether ketone (PEEEK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), copolymers thereof, and combinations, in particular mixtures (blends), thereof. Polyether ether ketone (PEEK) is particularly preferred.

[0041] The polyolefins can in particular be selected from the group consisting of polyethylene (PE), low density polyethylene, high density polyethylene, high molecular weight polyethylene (HMWPE), ultra-high molecular weight polyethylene (UHMWPE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyvinylidene chloride, polytetrafluoropropylene, polyhexafluoropropylene, copolymers thereof and combinations, in particular mixtures (blends), thereof.

[0042] The polyesters can in particular be selected from the group consisting of polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, copolymers and combinations, in particular mixtures (blends), thereof.

[0043] In a further embodiment of the invention, the sheathing body is formed as a layer or coating on the base or hollow body.

[0044] In a further embodiment of the invention, the sheathing body has a thickness of 0.1 mm to 30 mm, in particular 1 mm to 10 mm, preferably 2 mm to 5 mm.

[0045] Furthermore, the sheathing body can have a constant, ie uniform, thickness and / or a constant, ie uniform, shape, in particular in the axial direction or longitudinal direction.

[0046] In a further embodiment of the invention, the sheathing body has a varying, i.e., non-uniform, shape and / or thickness, particularly in the axial or longitudinal direction. This makes it particularly advantageous to accommodate (likewise) asymmetrically formed bone defects.

[0047] In a further embodiment of the invention, the thickness of the sheathing body, in particular in the axial direction or longitudinal direction, is greater at one end of the sheathing body than at another end of the sheathing body and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, towards one end of the sheathing body, in particular continuously or discontinuously, and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, from one end of the sheathing body to another end of the sheathing body, in particular continuously or discontinuously.

[0048] If the bone implant is a tibial implant, i.e. an implant for treating or supplying a tibial bone defect, the thickness of the sheathing body, in particular in the axial direction or longitudinal direction, is preferably greater at a distal end of the sheathing body than at a proximal end of the sheathing body and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, preferably in the direction of a distal end of the sheathing body, in particular continuously or discontinuously, and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, preferably from a proximal end of the sheathing body to a distal end of the sheathing body, in particular continuously or discontinuously.

[0049] If the bone implant is a femoral implant, i.e. an implant for treating or supplying a femoral bone defect, the thickness of the sheathing body, in particular in the axial direction or longitudinal direction, is preferably greater at a proximal end of the sheathing body than at a distal end of the sheathing body and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, preferably in the direction of a proximal end of the sheathing body, in particular continuously or discontinuously, and / or the thickness of the sheathing body increases, in particular in the axial direction or longitudinal direction, preferably from a distal end of the sheathing body to a proximal end of the sheathing body, in particular continuously or discontinuously.

[0050] In a further embodiment of the invention, the base or hollow body is partially not surrounded on the outside by the sheathing body.

[0051] In a further embodiment of the invention, the base or hollow body has a porous, particularly open-pore, and / or microstructured surface. This can induce osteointegration, i.e., the ingrowth or ingrowth of natural bone tissue. This, in turn, particularly advantageously promotes stable fixation or anchoring of the base body and thus of the bone implant at / in a bone defect. This, in particular, allows for improved secondary stability. Furthermore, the ingrowth or ingrowth of bone tissue advantageously reduces the size of the bone defect.

[0052] Preferably, the porous, in particular open-pored, surface of the base or hollow body has pores with a diameter, in particular an average diameter, determined by scanning electron microscopy and / or mercury porosimetry, of 10 µm to 400 µm, in particular 50 µm to 200 µm, preferably 100 µm to 135 µm. The pore diameters disclosed in this paragraph are particularly advantageous with regard to osteointegration of the base or hollow body.

[0053] Furthermore, pores, in particular of the surface, of the base or hollow body can be filled with an in vivo degradable / in vivo resorbable material. The pores can in particular be only partially or completely filled with the in vivo degradable / in vivo resorbable material. Preferably, the in vivo degradable / in vivo resorbable material that fills the pores, in particular of the surface, of the base or hollow body, and the in vivo degradable / in vivo resorbable material of the casing body or the plurality of shaped bodies are different from one another. This makes it possible to generate multi-stage, for example two-stage, degradation or resorption kinetics of the bone implant. This advantageously represents a further possibility for coordinating the mechanical stability of the bone implant, bone stimulation, and bone growth.With regard to suitable in vivo degradable / in vivo resorbable materials, reference is made to the in vivo degradable / in vivo resorbable materials disclosed in the following description in connection with the sheathing body and the plurality of shaped bodies.

[0054] The microstructured surface of the base or hollow body can be formed, for example, by a metal structure, in particular a metal lattice structure. The metal structure, in particular a metal lattice structure, is preferably a titanium structure, in particular a titanium lattice structure. A corresponding titanium structure is commercially available, for example, under the name Structan®. Regarding other suitable materials for the base or hollow body, reference is made to the materials previously described in connection with the base or hollow body.

[0055] For the purposes of the present invention, the term "microstructured surface" is to be understood as a surface with structural elements, in particular in the form of depressions and / or elevations, wherein the structural elements have dimensions, for example depths and / or heights, on the micrometer scale.

[0056] For example, the microstructured surface of the base or hollow body can have depressions with a depth of 20 µm to 1000 µm, in particular 100 µm to 600 µm, preferably 300 µm to 400 µm, and / or elevations with a height of 20 µm to 1000 µm, in particular 100 µm to 600 µm, preferably 300 µm to 400 µm.

[0057] Furthermore, the surface of the base or hollow body can be formed by a coating of the base or hollow body. In other words, the surface of the base or hollow body can be a surface of a coating which coats or covers the base or hollow body. The coating can coat or cover the base or hollow body at least partially, in particular only partially or completely. Furthermore, the coating can have a thickness of 0.01 µm to 1000 µm, in particular 1 µm to 100 µm, preferably 10 µm to 50 µm. Furthermore, the coating can have a porosity of 20% to 90%, in particular 50% to 85%, preferably 60% to 80%. The coating preferably comprises titanium, i.e. elemental or metallic titanium, or a calcium phosphate, preferably hydroxyapatite. For example, the coating can be a pure titanium coating, i.e. a coating consisting of titanium.A corresponding coating can be produced, for example, using a process developed by the applicant under the name Plasmapore®. In this process, pure titanium powder is applied to a substrate to be coated using a plasma coating process under vacuum or negative pressure, with a thickness of 150 µm and a porosity of 35% to 60%. Regarding other suitable materials for the coating, reference is made to the materials previously described in connection with the base or hollow body.

[0058] In a further embodiment of the invention, the covering body has a porous, particularly open-pore, and / or microstructured surface. This can (also) induce osteointegration and improve the secondary stability of the bone implant, as well as, depending on the material of the covering body, reduce the size of the bone defect.

[0059] Preferably, the porous, in particular open-pored, surface of the sheathing body has pores with a diameter, in particular an average diameter, determined by scanning electron microscopy and / or mercury porosimetry, of 20 µm to 1000 µm, in particular 50 µm to 500 µm, preferably 100 µm to 300 µm. The pore diameters disclosed in this paragraph are particularly advantageous with regard to osteointegration of the sheathing body.

[0060] Furthermore, pores, in particular of the surface, of the casing body can be filled with an in vivo degradable / in vivo resorbable material. The pores can in particular be only partially or completely filled with the in vivo degradable / in vivo resorbable material. Preferably, the in vivo degradable / in vivo resorbable material that fills the pores, in particular of the surface, of the casing body, and the in vivo degradable / in vivo resorbable material of the casing body are different from one another. This allows for multi-stage, for example two-stage, degradation or resorption kinetics of the bone implant to be developed. This advantageously represents a further possibility for coordinating the mechanical stability of the bone implant, bone stimulation, and bone growth.With regard to suitable in vivo degradable / in vivo resorbable materials, reference is made to the in vivo degradable / in vivo resorbable materials disclosed in the following description in connection with the sheathing body.

[0061] Furthermore, the microstructured surface of the sheathing body can have depressions with a depth of 20 µm to 1000 µm, in particular 100 µm to 600 µm, preferably 300 µm to 400 µm, and / or elevations with a height of 20 µm to 1000 µm, in particular 100 µm to 600 µm, preferably 300 µm to 400 µm.

[0062] Furthermore, the surface of the sheathing body can be formed by a coating of the sheathing body. In other words, the surface of the sheathing body can be a surface of a coating that coats or covers the sheathing body. The coating can coat or cover the sheathing body at least partially, in particular only partially or completely. Furthermore, the coating can have a thickness of 0.01 µm to 1000 µm, in particular 1 µm to 100 µm, preferably 10 µm to 50 µm. Furthermore, the coating can have a porosity of 20% to 90%, in particular 50% to 85%, preferably 60% to 80%. With regard to suitable materials for the coating, reference is made to the materials described below in connection with the sheathing body.

[0063] In a further embodiment of the invention, the shaped bodies or only a part of the shaped bodies have a porous, in particular open-pored, and / or microstructured surface.

[0064] In particular, the porous, in particular open-pored, surface of the shaped bodies can have pores with a diameter, in particular an average diameter, determined by scanning electron microscopy and / or mercury porosimetry, of 50 µm to 900 µm, in particular 150 µm to 700 µm, particularly preferably 300 µm to 400 µm. The microstructured surface of the shaped bodies can have depressions with a depth of 50 µm to 900 µm, in particular 150 µm to 700 µm, preferably 300 µm to 400 µm, and / or elevations with a height of 50 µm to 900 µm, in particular 150 µm to 700 µm, preferably 300 µm to 400 µm. This makes it particularly advantageous to achieve osteointegration and, depending on the material of the shaped bodies, also biological reconstruction and thus reduction of a bone defect to be treated or supplied.

[0065] Furthermore, pores, particularly on the surface, of the molded body can be filled with an in vivo degradable / in vivo resorbable material. The pores can, in particular, be only partially or completely filled with the in vivo degradable / in vivo resorbable material. Preferably, the in vivo degradable / in vivo resorbable material that fills the pores, particularly on the surface of the molded body, and the in vivo degradable / in vivo resorbable material of the molded body are different from one another. This makes it possible to generate multi-stage, for example two-stage, degradation or resorption kinetics of the bone implant. This advantageously represents a further possibility for coordinating the mechanical stability of the bone implant, bone stimulation, and bone growth.With regard to suitable in vivo degradable / in vivo resorbable materials, reference is made to the in vivo degradable / in vivo resorbable materials disclosed in the following description in connection with the shaped bodies.

[0066] Furthermore, the porous, in particular open-pored, surface of the shaped bodies or of a portion of the shaped bodies can be formed by a coating of the shaped bodies. The coating can coat or cover the shaped bodies at least partially, in particular only partially or completely. Furthermore, the coating can have a thickness of 0.01 µm to 1000 µm, in particular 1 µm to 100 µm, preferably 10 µm to 50 µm. Furthermore, the coating can have a porosity of 20% to 90%, in particular 50% to 85%, preferably 50% to 70%. With regard to further suitable materials for the coating, reference is made to the materials described below in connection with the shaped bodies.

[0067] Furthermore, the microstructured surface of the shaped bodies or of a part of the shaped bodies can have depressions with a depth of 50 µm to 900 µm, in particular 150 µm to 700 µm, preferably 300 µm to 400 µm, and / or elevations with a height of 50 µm to 900 µm, in particular 150 µm to 700 µm, preferably 300 µm to 400 µm.

[0068] Furthermore, the shaped bodies can have a thickness, ie wall thickness or height, in particular a constant, ie uniform, or varying, ie non-uniform, thickness, ie wall thickness or height, of 1 mm to 30 mm, in particular 5 mm to 20 mm, preferably 8 mm to 15 mm.

[0069] Advantageously, the total wall thickness of the bone implant can be controlled in a targeted and thus application-oriented manner via the thickness of the shaped bodies or the thickness of the casing body as well as via the wall thickness of the base or hollow body.

[0070] Furthermore, the shaped bodies are preferably designed as flat structures, i.e. the shaped bodies preferably have a length and a width which are greater than a thickness (height) of the shaped bodies. The shaped bodies are preferably plate-shaped and / or disc-shaped. In particular, the shaped bodies can each have two oppositely arranged main surfaces, which are each delimited by two oppositely arranged transverse side surfaces and by two oppositely arranged longitudinal side surfaces. In principle, the transverse side surfaces can be flat, i.e. flat or not curved, and / or curved, in particular curved outwards. Furthermore, the longitudinal side surfaces can basically be flat, i.e. flat or not curved, and / or curved, in particular curved outwards. For example, the shaped bodies can each have a curved, in particular outwards curved, longitudinal side surface and otherwise flat side surfaces, i.e.one flat longitudinal side surface and two flat transverse side surfaces.

[0071] Furthermore, the shaped bodies, or a portion of the shaped bodies, can each have at least one predetermined breaking line, in particular only one predetermined breaking line or a plurality of predetermined breaking lines. The predetermined breaking line(s) preferably extend in the longitudinal direction of the shaped bodies. The predetermined breaking line(s) can be designed, for example, as perforations, notches, or scratch marks. This allows for additional adaptation of the shaped bodies and thus of the bone implant to patient-specific bone defects. In particular, this can (additionally) reduce or completely prevent bone loss by adapting a bone defect to the bone implant.

[0072] In a further embodiment of the invention, the in vivo degradable / in vivo resorbable material, in particular the at least two different in vivo degradable / in vivo resorbable materials, are selected from the group consisting of metals, polyhydroxyalkanoates, polycaprolactone, poly-p-dioxanone (poly-1,4-dioxan-2-one), polymethylene terephthalate, calcium phosphates, calcium sulfates, calcium oxide (CaO), calcium hydroxide (Ca(OH) 2 ), calcium carbonate (CaCO 3 ), calcium citrate, calcium lactate, calcium acetate, calcium tartrate, calcium chloride (CaCl 2 ), magnesium phosphates, magnesium sulfates, magnesium hydroxide (Mg(OH) 2 ), magnesium hydroxide carbonate (for example as 4 MgCO 3 x Mg(OH) 2 x 5 H 2 O), magnesium oxide (MgO), magnesium citrates (Mg 3 (C 6 H 5 O 7 ) 2 ) or Mg(C 6 H 6 O 7 )), calcium magnesium carbonate (CaMg(CO 3 ) 2 and combinations, especially mixtures, thereof.

[0073] The metals used are preferably magnesium.

[0074] The polyhydroxyalkanoates can in particular be selected from the group consisting of polylactide, polyglycolide, poly-3-hydroxybutyrate, poly-4-hydroxybutyrate, copolymers thereof and combinations, in particular mixtures (blends), thereof.

[0075] The calcium phosphates can in particular be selected from the group consisting of tricalcium phosphate (TCP) such as α-tricalcium phosphate (α-TCP) and / or β-tricalcium phosphate (β-TCP), apatites such as hydroxyapatite (HA), calcium-deficient hydroxyapatite (CdHA), substituted hydroxyapatite, non-stoichiometric hydroxyapatite, nanoscale hydroxyapatite, tetracalcium phosphate (TTCP), monocalcium phosphate monohydrate (MCPM), monocalcium phosphate anhydride (MCPA), dicalcium phosphate anhydride (DCPA), dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), calcium glycerophosphate and combinations, in particular mixtures, thereof.

[0076] The calcium sulfates can in particular be selected from the group consisting of calcium sulfate (CaSO 4 ), calcium sulfate hemihydrate (CaSO 4 x 0.5 H 2 O), calcium sulfate dihydrate (CaSO 4 x 2 H 2 O) and combinations, in particular mixtures, thereof.

[0077] The magnesium phosphates can in particular be selected from the group consisting of magnesium hydrogen phosphate (MgHPO 4 ) in the form of the hydrates or as an anhydrous substance, trimagnesium phosphate (Mg 3 (PO 4 ) 2 ), magnesium dihydrogen phosphate (Mg(H 2 PO 4 ) 2 ) in the form of the hydrates or as an anhydrous substance, magnesium glycerophosphate and combinations, in particular mixtures, thereof.

[0078] The in vivo degradable / in vivo resorbable material is particularly preferably tricalcium phosphate. The tricalcium phosphate can be in crystalline form. In particular, the tricalcium phosphate can have a crystallinity of 50% to 99%, in particular 75% to 95%. Furthermore, the tricalcium phosphate can be a microcrystalline tricalcium phosphate, i.e. tricalcium phosphate with crystallites which have at least one dimension in the micrometer range, in particular in a range of > 0.5 µm, in particular 0.6 µm to 500 µm, preferably 0.6 µm to 100 µm. The at least one dimension can be the length and / or the width and / or the thickness or height and / or the diameter, in particular the average diameter, of the crystallites. Alternatively, the tricalcium phosphate can be a nanocrystalline tricalcium phosphate, i.e.Tricalcium phosphate with crystallites that have at least one dimension in the nanometer range, in particular in a range from 0.1 nm to 500 nm, preferably 0.1 nm to 100 nm. The at least one dimension can be the length and / or the width and / or the thickness or height and / or the diameter, in particular the average diameter, of the crystallites. Alternatively, the tricalcium phosphate can be a macrocrystalline tricalcium phosphate. Alternatively, the tricalcium phosphate can be in amorphous form. Furthermore, the tricalcium phosphate can be a phase-pure tricalcium phosphate. The term "phase-pure" here is to be understood in particular as phase-pure in the sense of a relevant standard, preferably according to ASTM F1088. Furthermore, the tricalcium phosphate can have a porosity of < 50%, in particular < 20%, preferably < 15%.Alternatively, the tricalcium phosphate can be non-porous. Preferably, the tricalcium phosphate is selected from the group consisting of α-tricalcium phosphate (α-TCP), β-tricalcium phosphate (β-TCP), and a mixture thereof. Particularly preferably, the tricalcium phosphate is a sintered tricalcium phosphate, preferably selected from the group consisting of sintered α-tricalcium phosphate (sintered α-TCP), sintered β-tricalcium phosphate (sintered β-TCP), and a mixture thereof.

[0079] Alternatively, the in vivo degradable / in vivo resorbable material can in particular be hydroxyapatite. The hydroxyapatite can be in crystalline form. In particular, the hydroxyapatite can have a crystallinity of 50% to 99%, in particular 75% to 95%. Furthermore, the hydroxyapatite can be a microcrystalline hydroxyapatite, i.e. a hydroxyapatite with crystallites which have at least one dimension in the micrometer range, in particular in a range of > 0.5 µm, in particular 0.6 µm to 500 µm, preferably 0.6 µm to 100 µm. The at least one dimension can be the length and / or the width and / or the thickness or height and / or the diameter, in particular the average diameter, of the crystallites. Alternatively, the hydroxyapatite can be a nanocrystalline hydroxyapatite, i.e.a hydroxyapatite with crystallites that have at least one dimension in the nanometer range, in particular in a range from 0.1 nm to 500 nm, preferably 0.1 nm to 100 nm. The at least one dimension can be the length and / or the width and / or the thickness or height and / or the diameter, in particular the average diameter, of the crystallites. Alternatively, the hydroxyapatite can be a macrocrystalline hydroxyapatite. Furthermore, the hydroxyapatite can be a phase-pure hydroxyapatite. The term "phase-pure" in this context is understood to mean phase-pure in the sense of a relevant standard, preferably according to ASTM F1185. Furthermore, the hydroxyapatite can have a porosity of < 50%, in particular < 20%, preferably < 15%. High mechanical stability can be achieved through low porosity.Alternatively, the hydroxyapatite may be non-porous. The hydroxyapatite may also, in particular, be a sintered hydroxyapatite.

[0080] Furthermore, the sheathing body and / or the molded bodies or a portion of the molded bodies may comprise or consist of a material that is non-degradable / non-absorbable in vivo. Regarding suitable non-degradable / non-absorbable in vivo materials, reference is made to the materials mentioned above in connection with the base or hollow body.

[0081] Furthermore, the sheathing body and / or the shaped bodies or a portion of the shaped bodies can comprise both an in vivo degradable / in vivo resorbable material and an in vivo non-degradable / in vivo non-resorbable material, or can consist of both an in vivo degradable / in vivo resorbable material and an in vivo non-degradable / in vivo non-resorbable material. With regard to suitable in vivo degradable / in vivo resorbable materials and in vivo non-degradable / in vivo non-resorbable materials, reference is made entirely to the materials disclosed in the previous description.

[0082] Furthermore, the bone implant can be manufactured using an additive or generative manufacturing process. In particular, the casing body and / or the shaped bodies can be molded or attached to the base or hollow body externally, i.e., to an outer surface of the base or hollow body, using an additive or generative manufacturing process. Regarding further features and advantages of such a process, reference is made in full to the following statements made within the scope of the second aspect of the invention.

[0083] According to a second aspect, the invention relates to a method for producing a bone implant, in particular a bone implant according to the first aspect of the invention.

[0084] In this procedure, the bone implant is manufactured using an additive or generative manufacturing process, i.e., 3D printing.

[0085] Alternatively or in combination, a base body in the form of a hollow body which is open or open on both sides in the axial direction and which has a load-bearing material or consists of a load-bearing material is coated, in particular cohesively coated, by means of the additive or generative manufacturing process, i.e. by means of 3D printing, at least partially, in particular only partially or completely, with a sheathing body which has or consists of an in vivo degradable / in vivo resorbable material, or is connected, in particular cohesively connected, to a plurality of shaped bodies which have an in vivo degradable / in vivo resorbable material or consist of an in vivo degradable / in vivo resorbable material in such a way that the shaped bodies protrude or protrude from the base body in the radial direction. The base body or hollow body is preferably conical.

[0086] For the purposes of the present invention, the terms "additive manufacturing process" or "generative manufacturing process" or "3D printing" refer to processes for the rapid and cost-effective production of models, samples, prototypes, tools, semi-finished products, and end products, such as bone implants. These processes are often also referred to as "rapid prototyping." Production takes place directly on the basis of computer-internal data models, particularly from formless material, for example, liquids, melts, powders, or the like, or from form-neutral material, such as strip or wire material, using chemical and / or physical processes.

[0087] A generative or additive manufacturing process offers the particular advantage of being able to specifically influence the bone implant in terms of materials and / or shape and / or geometry and / or surface structure.

[0088] The generative manufacturing process can in particular be selected from the group consisting of powder bed processes, free space processes and liquid material processes.

[0089] The powder bed process can be selected from the group consisting of selective laser melting, selective laser sintering, selective heat sintering, solidification of powder material by means of a binder (binder jetting) and electron beam melting.

[0090] The free space process can be selected from the group consisting of fused deposition modeling, LOM (laminated object modeling), cladding, wax deposition modeling, contour grafting, cold spraying and electron beam melting.

[0091] The liquid material process can be selected from the group consisting of stereolithography, DLP (digital light processing), and LCM. The LCM process can be a liquid composite molding process or a lithography-based ceramic manufacturing process.

[0092] With regard to further features and advantages of the method, in particular the bone implant, the base body, the covering body, and the shaped bodies, reference is made in full to the statements made in the context of the first aspect of the invention. The statements made therein also apply mutatis mutandis to the method according to the second aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Further features and advantages of the invention will become apparent from the claims and the following description of preferred embodiments of the invention, which are explained below with reference to the figures. In the figures: Fig. 1 schematically shows an embodiment of a bone implant according to the invention, Fig. 2 schematically shows a further embodiment of a bone implant according to the invention and Fig. 3 schematically shows a further embodiment of a bone implant according to the invention. DETAILED FIGURE DESCRIPTION

[0094] The Fig. 1 The schematically illustrated bone implant 1 has a base body 10 and a covering body 20.

[0095] The base body 10 is designed in the form of a hollow body that is open or open on both sides in the axial direction A and is preferably conical.

[0096] The base body 10 comprises or consists of a load-bearing material. The load-bearing material is preferably a material that is non-degradable / non-resorbable in vivo, such as a titanium alloy or a plastic, such as polyetheretherketone. This particularly advantageously achieves both sufficient primary and secondary stability of the bone implant 1 after its placement on / in a bone defect. Regarding further suitable materials for the base body 10, reference is made to the general description.

[0097] The base body 10 is preferred, as in Fig. 1shown, completely surrounded or encased by the sheathing body 20. The sheathing body 20 comprises an in vivo degradable / in vivo resorbable material or consists of such a material. The in vivo degradable / in vivo resorbable material can be, for example, a calcium phosphate, in particular β-tricalcium phosphate and / or hydroxyapatite. Alternatively, the in vivo degradable / in vivo resorbable material can be a polymer, such as polycaprolactone, or a metal, such as magnesium. With regard to further suitable materials for the sheathing body 20, reference is made to the general description.

[0098] The (at least partially) in vivo degradable / in vivo resorbable sheathing body 20 particularly advantageously enables the biological reconstruction of a bone defect to be treated or repaired, such as a tibial or femoral bone defect. A particular advantage is that the biological reconstruction allows the size of the bone defect to be minimized. This reduces the risk of any revision surgery. If necessary, reducing the size of the bone defect creates more favorable starting conditions for successful revision surgery.

[0099] The base body 10 can, for example, have a wall thickness of 3 mm to 5 mm, while the sheathing body 20 can, for example, have a sheath thickness of 2 mm to 10 mm.

[0100] The sheathing body 20 can, as in Fig. 1shown, have a uniform thickness. Alternatively, the sheathing body can have a non-uniform thickness, particularly in the axial or longitudinal direction (not shown). This can accommodate, in particular, asymmetrically formed bone defect structures.

[0101] Furthermore, the sheathing body 20 can have an open-pored surface. Alternatively, the sheathing body 20 can be designed to be completely or continuously open-pored. The two aforementioned embodiments for the sheathing body 20 particularly advantageously achieve osteointegration, i.e., the ingrowth and / or in-growth of bone tissue onto and / or into the sheathing body 20. This, in turn, contributes to a further improvement in the primary and secondary stability of the bone implant 1.

[0102] Furthermore, the sheathing body comprises, particularly in regions or layers, different in vivo degradable / in vivo resorbable materials, which differ from one another with regard to their in vivo degradation rate / in vivo resorption rate. This particularly advantageously enables different degradation / resorption kinetics of the sheathing body 20 and, in particular, control of the mechanical stability of the bone implant 1, bone stimulation, and bone growth.

[0103] Fig. 2 shows a further embodiment of a bone implant 1 according to the invention.

[0104] The bone implant 1 has a base body 10 and a covering body 20 that only partially surrounds the base body 10.

[0105] The base body 10 is in the form of a preferably conical hollow body that is open or open on both sides in the axial direction A. The base body 10 has a load-bearing material or consists of a load-bearing material. The load-bearing material is preferably a material that is not degradable / resorbable in vivo, such as a titanium alloy, in particular the titanium alloy Ti-6Al-4V. This is a titanium alloy that has titanium, aluminum and vanadium and optionally impurities, in particular in the form of iron and / or oxygen and / or carbon and / or nitrogen and / or hydrogen, or consists of titanium, aluminum and vanadium and optionally impurities, in particular in the form of iron and / or oxygen and / or carbon and / or nitrogen and / or hydrogen.In addition to titanium, the titanium alloy preferably has an aluminum content of 5.5 mass percent to 6.75 mass percent, in particular 6 mass percent, a vanadium content of 3.5 mass percent to 4.5 mass percent, in particular 4 mass percent, and optionally an iron content of 0.4 mass percent and / or an oxygen content of 0.2 mass percent and / or a carbon content of 0.08 mass percent and / or a nitrogen content of 0.05 mass percent and / or a hydrogen content of 0.015 mass percent or consists of the aforementioned elements / components. In particular, the base body 10 can have a lattice structure, preferably made of Ti-6Al-4V. With regard to further suitable materials for the base body 10, reference is made to the general description and to the description of the. Fig. 1 Reference is made.

[0106] By only partially covering the base body 10 with the covering body 20, an application-oriented control of the thickness of the bone implant 1 is advantageously possible. Preferably, the non-covered region 12 of the bone implant 1 is intended to accommodate an extension shaft (not shown) of a joint implant. If the bone implant 1 is a tibial bone implant, the non-covered section 12 represents a proximal section of the bone implant. If, however, the bone implant 1 is a femoral bone implant, the non-covered section 12 represents a distal section of the bone implant.

[0107] Regarding further features and advantages of the bone implant 1, in particular of the base body 10 and the sheathing body 20, in order to avoid repetition, reference is made entirely to the description of Fig. 1The features and advantages described therein with regard to the bone implant 1, in particular the base body 10 and the covering body 20, also apply mutatis mutandis to the Fig. 2 shown bone implant 1.

[0108] Fig. 3 shows a further embodiment of a bone implant 1 according to the invention.

[0109] The Fig. 3 The schematically illustrated bone implant system 1 comprises a base body 10 and a plurality of shaped bodies 20. Six shaped bodies 20 are shown as an example. It is understood that the bone implant 1 may also comprise fewer or more shaped bodies.

[0110] The base body 10 is designed as a conical hollow body that is open or opened on both sides in the axial direction A.

[0111] The base body 10 comprises a load-bearing material, in particular a titanium alloy such as Ti-6Al-4V, or a plastic, in particular polyetheretherketone, or consists of such a material. This advantageously achieves sufficient primary and secondary stability. Regarding other suitable materials for the base body 10, reference is made to the general description and the description of the Fig. 1 and 2 Reference is made.

[0112] The base body 10 preferably has a wall 11 with two openings or recesses 12, preferably arranged opposite one another. The openings or recesses 12 are preferably U-shaped.

[0113] The shaped bodies 20 comprise or consist of an in vivo degradable / in vivo resorbable material. This particularly advantageously allows for the biological reconstruction of a bone defect. The biological reconstruction of the bone defect advantageously minimizes the size of the bone defect. This, in turn, reduces the risk of revision surgeries and / or creates favorable conditions for the successful performance of revision surgeries. The in vivo degradable / in vivo resorbable material can be, for example, a calcium phosphate, in particular β-tricalcium phosphate and / or hydroxyapatite. Alternatively, the in vivo degradable / in vivo resorbable material can be a polymer, such as polycaprolactone, or a metal, such as magnesium.With regard to further suitable materials for the casing body 20, reference is made to the general description as well as to the description of the . Fig. 1 and 2 Reference is made.

[0114] The shaped bodies 20 protrude radially from the base body 10. The shaped bodies 20 are integrally connected to the base body 10 or are integrally attached to it.

[0115] For example, the molded bodies 20 can be glued or welded to the base body 10. Alternatively, the molded bodies 20 can be molded onto the outside, i.e., onto an outer surface 12 of the base body 10, using a generative manufacturing process.

[0116] The molded bodies 20 are preferably designed as flat structures, in particular in the form of plates or discs. This means that the molded bodies 20 have a length and a width that are smaller than a thickness (height) of the molded bodies 20. Preferably, the molded bodies 20 each have two oppositely arranged main surfaces, which are each delimited by two oppositely arranged transverse side surfaces and by two oppositely arranged longitudinal side surfaces.

[0117] To improve the osteointegration of the bone implant 1, it may further be preferred if the shaped bodies 20 each have a porous, in particular open-pored, and / or microstructured surface or consist of a porous, in particular open-pored, material. Regarding a suitable material in this respect, reference is also made to the general description as well as to the description of the Fig. 1 and 2 Reference is made.

Claims

1. A bone implant comprising - a main body in the form of a hollow body open on both sides in the axial direction, comprising or consisting of a load-bearing material, and - an encasing body which at least partially encases the main body on the outside and comprises an in vivo degradable / in vivo resorbable material or consists of an in vivo degradable / in vivo resorbable material, or a multiplicity of shaped bodies which protrude from the main body in the radial direction and comprise an in vivo degradable / in vivo resorbable material or consist of an in vivo degradable / in vivo resorbable material, characterized in that the encasing body and the shaped bodies, respectively each comprise at least two different in vivo degradable / in vivo resorbable materials which differ from one another with regard to their in vivo degradation rate / in vivo resorption rate.

2. The bone implant as claimed in claim 1, characterized in that the main body has a corner-free, in particular circular, oval or elliptical, cross section.

3. The bone implant as claimed in claim 1 or 2, characterized in that the main body is conical and has an at least sectionally tapering inner diameter.

4. The bone implant as claimed in any of the preceding claims, characterized in that the main body has a wall thickness of 1 mm to 30 mm, in particular 5 mm to 20 mm, preferably 8 mm to 15 mm.

5. The bone implant as claimed in any of the preceding claims, characterized in that the load-bearing material of the main body is an in vivo nondegradable / in vivo nonresorbable material.

6. The bone implant as claimed in any of the preceding claims, in particular as claimed in claim 5, characterized in that the load-bearing material, in particular the in vivo nondegradable / in vivo nonresorbable material, is selected from the group consisting of metals such as titanium and / or tantalum, alloys such as titanium alloys, ceramics, plastics, polyetherketones, polyetheretherketone, polyetherketoneketone, polyetheretheretherketone, polyetheretherketoneketone, polyetherketoneetherketoneketone, polyolefins and combinations thereof.

7. The bone implant as claimed in any of the preceding claims, characterized in that the encasing body is in the form of a layer or coating on the main body.

8. The bone implant as claimed in any of the preceding claims, characterized in that the encasing body has a thickness of 0.1 mm to 30 mm, in particular 1 mm to 10 mm, preferably 2 mm to 5 mm.

9. The bone implant as claimed in any of the preceding claims, characterized in that the encasing body has a nonuniform shape and / or thickness in the axial direction.

10. The bone implant as claimed in claim 9, characterized in that the thickness of the encasing body is greater at one end of the encasing body than another end of the encasing body and / or the thickness of the encasing body increases toward one end of the encasing body.

11. The bone implant as claimed in any of the preceding claims, characterized in that the main body is partially not encased by the encasing body on the outside.

12. The bone implant as claimed in any of the preceding claims, characterized in that the main body and / or the encasing body and / or the shaped bodies have a porous, in particular open-pored, and / or microstructured surface.

13. The bone implant as claimed in any of the preceding claims, characterized in that the at least two different in vivo degradable / in vivo resorbable materials are selected from the group consisting of polyhydroxyalkanoates such as polylactide and / or polyglycolide, polycaprolactone, calcium phosphates such as β-tricalcium phosphate and / or hydroxyapatite and combinations thereof.

14. A method for producing a bone implant as claimed in any of the preceding claims, characterized in that a main body in the form of a hollow body open on both sides in the axial direction, comprising or consisting of a load-bearing material, is, by means of an additive manufacturing process, at least partially encased by an encasing body comprising or consisting of an in vivo degradable / in vivo resorbable material or connected to a multiplicity of shaped bodies comprising or consisting of an in vivo degradable / in vivo resorbable material in such a way that the shaped bodies protrude from the main body in the radial direction.