DD298737A5 - ONE-PIECE CEMENT FREE IMPLANTABLE JOINT PAN - Google Patents

Abstract

The invention relates to one-piece cementless implantable joint sockets consisting of a basic body made of titanium or a titanium alloy, which is covered on all sides with a Titaniumoxidhaut. The tread for the convex counterpart is formed by a composite material consisting of a polymer matrix with embedded glassy-crystalline inorganic biomaterials, which arises in contact with the titanium oxide-covered basic body by polyaddition. The invention can be used in human medicine. {Cementless implantable acetabulum; endoprosthesis; Reinsttitanium; Titaniumoxidhaut; Titanium composite material composite; Polymer matrix; glassy crystalline inorganic biomaterial; polyurethane; epoxy}

Description

For this 1 page drawings

Field of application of the invention

The invention relates to a one-piece cementless implantable joint socket high biocompatibility, which is anchored positively and non-positively in the bone and is used as an endoprosthesis in human medicine.

Characteristic of the known state of the art

As a cement-free anchored joint pans previously mainly multi-part systems are used. Moist consists of such a system of a biocompatible metallic shell, which is anchored positively and non-positively in the bone bed and a polymer inlay preferably made of high molecular weight polyethylene as the concave sliding partner in the joint, which in turn is only positively and non-positively connected to the metallic shell. In the case of the hip joint endoprosthesis shells, there are many technical solutions to counteract the loosening of both the metal shell in the bone bed and the inlay in the shell due to high shear forces. So z. B. in WO 85/02535 for anchoring the shell in the bone bed a perforated unilaterally open cylindrical anchoring part and for anchoring the Polymerinlays interlocking latching means (locking elements) proposed. In OS DE OS 3630276 a cementless implantable acetabulum is described, which is intended to remedy the pan loosening occurring in practice by a self-tensioning device and in which the form-fitting fitted inner pan expands by driving into the outer pan latter and presses against the bone stock.

In the tibial plateau of knee joint prostheses, the polymer tread is also only positive and non-positively attached to the most cast metal substrate consisting of a cobalt-chromium-molybdenum alloy (slide prosthesis from Link).

The disadvantages of all these solutions are mainly due to the fact that there are gaps between the polymer part and the metal part, which are to be regarded as a potential hotbed for infections, regardless of whether the system is completed before the operation, or assembled during the operation becomes. In addition, manufacturing-related Paßungenauigkeiten can lead to a loose SiU of the inlay in the metal housing or on the metal pad, resulting in a radiologically poorly controlled relative movement inlay metal jacket with abrasion and dislocation tendency of the inlay and the metal shell.

Object of the invention

The aim of the invention is to develop one-piece cementless implantable joint sockets, which guarantee a long period of time, reduce the rate of reopration and can be produced in a relatively uncomplicated way.

Explanation of the essence of the invention

Dio object of the invention is to develop one-piece cementless implantable joint sockets with high biocompatibility and mechanical stability and wear resistance of the sliding surfaces, which precludes a relative movement of parts of the pans with each other.

According to the invention this object is achieved in that a machined or non-cutting produced body made of pure titanium or a biocompatible ^T itanium alloy on all sides wearing an oxide produced by anodic radio discharge oxide of semicrystalline titanium oxide, which serves as a contact surface both on the bone side and to a tread composite material consisting of a Polymer matrix with embedded glassy crystalline inorganic biomaterials, serves and thereby an insoluble, dense biocompatible Titanium composite composite is constructed.

The oxide skin has a thickness of 3μηπ up to 10um, consists of at least 20% rutile and / or anatase, and at least 20% X-ray amorphous constituents.

Another feature of this titanium oxide skin is the typical surface profile produced by anodic oxidation under spark discharge (ANOF) method with at least 10 * pores per square millimeter having a diameter greater than 1 μm and a maximum pore depth of Va of the titanium oxide skin thickness.

Both for the formation of a solid as possible bone-side composite of the implant as well as for the composite with the composite material, it proves to be advantageous that the Titaniumoxidhaut contains calcium and phosphate ions.

These ions originate from the ANOF electrolyte and are incorporated into the oxide skin by up to 20% during the formation of the titanium oxide skin.

According to the invention, the contact surface of the titanium oxide-coated titanium base body is formed into the composite material in which a polyaddition in contact with the ANOF titanium oxide skin and in contrast from 20 to 70% of a glassy crystalline inorganic biomaterial, based on the polymer component, with a grain size of 50 to 500 μm, preferably 63 to 200 pm takes place.

The glassy-crystalline inorganic biomaterial belongs in its chemical composition to the basic system P ₂ Oi-CaO-SiO ₂ . It goes without saying that, of course, other additives may be included in particular substances that improve the hydrolytic stability of biomaterials such as Al ₂ Oj, ZrO ₂ , TiO _2, etc. Studies have shown that it proves to be advantageous if the biomaterial not purely glassy, but in glasigki 'stalliner form present. Apatite and / or wollastonite are used with advantage in this case as crystalline main phases. MeK · or less due to the, the hydrosis stability increasing substances occur, secondary crystal phases, which can be tolerated up to a content of 25% '.

Investigations showed that it does not matter by which route the glassy-crystalline biomaterial was produced, i. For the purposes of the present invention, it is possible to use a glass ceramic and / or a ceramic and / or a sintered glass ceramic with the features mentioned above.

The polymer matrix material used is preferably polyurethanes or epoxy resins. The content of functional groups, which cause a firm bond between the polymer material and the partially crystalline titanium oxide on the Titaniumgrundlcörper on the one hand and the embedded semi-crystalline Bioglaskeramik on the other hand, must be at least 10%.

The urethane groups capable of hydrogen bonding act as such groups in polyurethanes, whereas in epoxy resins the hydroxyl groups formed as hardeners when using polyamines, or when using

Anhydrides exert the ester groups formed, such interactions. '

It is in the nature of the invention that the elastic polymer matrix is crosslinked and has a glass transition temperature above body temperature. For this purpose, when using polyurethane casting resins, the polyol functionality between 2, ι and 4.0, preferably between 3.3 and 3.6 set. For the same reason, it is necessary that the hydroxyl equivalent weight of the polyol between 100 and 300 g of component per mole of OH is preferably set to 150 g / mol to 220 g / mol.

As diisocyanates, aromatic and cycloaliphatic diisocyanates are preferred as crosslinking components.

In the case of epoxy resins, the glass tautness is achieved by using diglycidyl ethers of the aromatic diphenols or else by using isocyanurate triglycidyl ether and by using phaloic anhydride, hexahydrophthalic anhydride and similar conventional epoxy resin hardeners.

It has been found that the combination of the titanium oxide-coated titanium surface with a partially crystalline titanium oxide and the casting resin reacting by polyaddition, in the presence of likewise semi-crystalline bioceramics, results in a solid cohesive bond. The titanium oxide skin acts not only as an adhesion-promoting intermediate layer and the inorganic bioceramics in the polymer matrix not only as a filler, but it is shown to form bonds both between the inorganic and the organic phases on the one hand but also between the morphologically and chemiech similar inorganic phases of Titaniumoxidhaut and the glassy-crystalline bioceramics with each other.

The overall composite becomes particularly strong when the bioceramic concentration is close to the critical pigment volume concentration. This guarantees that the interactions between the contacting ceramic particles counteract leaching out of the composite. In addition, there are many points of contact and thus interactions between the glassy-crystalline bioceramic particles and the titanium-oxide-covered titanium surface.

According to the invention, in this way, a dense series of stable compounds of titanium over the amorphous-crystalline titanium oxide up to the last biomaterial grain in the polymer matrix forms on the concave running surface for the convex counterpart of the joint, which guarantee good composite stability.

Another advantage of the solution according to the invention is that the embedding of the glassy-crystalline biomaterial

in the polymer matrix or the partial penetration of polymer material into the porous titanium oxide skin of the

Titanium basic body as well as the formation of chemical bonds, the effects of voltage peaks

be minimized dynamic loads.

Thus, the permanent composite strength of Ge. ladles by combining titanium oxide layered titanium polyadduct

determined with incorporated glassy crystalline inorganic biomaterials.

Finally, the calcium and phosphate doping of the. Ensures a trouble-free healing of the joint sockets in the bone bed Titanium oxide skin on the outer surface of the socket with the typical generated by the ANOF process Micropatterning. This results in the implanted state, a structure with gradual transition of participating in the overall composite Components, from the living bone connective tissue over the calcium and phosphate-containing semi-crystalline, porous Titanium oxide skin and the titanium base body to the composite material. The gradual transition from the titanium basic body to the composite material is achieved in particular by the fact that the

partially crystalline titanium oxide components decrease in the extent in the polymer matrix, as well as the calcium and

Phosphate-containing and also partially crystalline biomaterial increases. embodiment

The invention will be described below with reference to two embodiments. The accompanying drawings show

Fig. 1: Schematic structure of a hip cup prosthesis Fig. 2: Schematic structure of the titanium composite composite composite Embodiment 1

1 is washed fat-free and chemically shined for 10 seconds at room temperature in a mixture of equal parts of a 65% nitric acid and 40% hydrofluoric acid and then rinsed acid-free with water The all-round ANOF coating then takes place on the anodically poled molded body 1 in a saturated aqueous solution of calcium dihydrogen phosphate by means of a pulsed DC voltage with voltage peaks greater than 220V until the coating flow has fallen to less than 10% of the initial value.

After thorough rinsing of the molded body 1 with distilled water and subsequent drying at 200 ° C, the molded body 1 is placed on a casting device with a hemisphere as the core.

The composite titanium composite according to the invention is produced by a bubble-free pouring of the cavity between the ANOF-coated molded body 1 and the core of the casting apparatus at 4O ⁰ C with a reacting mixture which is prepared as follows:

20g of a polyol mixture prepared by mixing Ricinolsäuretrimethylpropanesters with trimethylolpropane with the hydroxyl equivalent 190g ester per mole of OH and a functionality of 3.0 and a viscosity at 4O ⁰ C of 10OOmPas are first coated with 20 g of the vitreous-crystalline inorganic Biomaterials 4 ILMAPLANT * -L1 grit 63pm intimately mixed up to 200 μσι. Here, the ILMAPLANT powder must be previously pre-dried for at least one hour at 200 ⁰ C. In the suspension thus prepared polyester polyol and ILMAPLANT ^ -Li powder 10g freshly distilled toluene diisocyanate (equivalent weight 90 g / mol NCO) were added, after which the at 4O ⁰ C pourable reacting mixture. The curing takes place at temperatures between 40 ° C and 80 ° C and is completed after 12 hours. After this time, the core is removed and the composite material 2 subjected to a quality control on possibly resulting casting defects. Fig. 2 shows in cross-section the overall structure of the resulting joint socket with the inventive combination titanoxidbeschichtetes titanium 1 / polyadduct 3 with embedded glassy crystalline inorganic biomaterials 4, the polyadduct 3 with the embedded glassy inorganic biomaterial 4 form the composite material 2 and the sides of the titanium main body. 1 covering titanium oxide skin contains 5 calcium and phosphate.

Embodiment 2

A shaped body 1 made of EMO-Ti 140 for a cementless implantable hip shell prosthesis is covered on all sides according to exemplary embodiment 1 with a titanium oxide skin 5, and then the composite titanium composite according to the invention with the reactive mixture described below is produced analogously to exemplary embodiment 1. 14 g of a crystalline epoxy resin based on isocyanuric acid are brought to polyaddition with 20 g of freshly distilled hexahydrophthalic anhydride and 35 g of the glassy crystalline inorganic biomaterial ILMAPLANT ^ -L 1 of grain size 63pm to 200mm at 110 ⁰ C. After a 20-minute pre-reaction pouring takes place in the preheated to 100 ° C provided with the Titanoxidhaut 5 titanium basic body 1 according to embodiment 1. The curing is completed at a temperature of 110 ° C after 24 h.

Claims (4)

1. One-piece, cementless implantable acetabulum, characterized in that it consists of an insoluble, dense biocompatible titanium composite material composite, wherein the main body (1) of pure titanium or a biocompatible titanium alloy on all sides with a firmly adhering 3 μνη to 10μηη strong Titaniumoxidhaut ( 5) which contains calcium and phosphate and whose hinged surface is integrally bonded to the composite material (2) consisting of crosslinked polymers forming the polymer matrix (3) and intercalated glassy crystalline inorganic biomaterials (4). 2. One-piece, cementless implantable acetabulum according to claim 1, characterized in that the denTitaniumgrundkörper (1) enclosing all sides titanium oxide skin (5) is partially crystalline, contains at least 20% each of rutile and / or anatase and X-ray amorphous constituents, at least 10 ⁴ pores greater than 1 pm per square millimeter with a pore depth of ² h of Titaniumoxidschichtdicke and that are used as a polymer matrix polyurethanes or epoxies. 3. One-piece, cementless implantable acetabular cup according to claim 1 and 2, characterized in that the composite material (2) is formed as a tread for the convex counterpart, 20 to 70% vitreous crystalline inorganic biomaterials (4) and the polymer matrix by polyaddition in contact with the Titanium oxide skin (5) of titanium basic body (1) is formed. 4. One-piece, cementless implantable acetabulum according to claim 1 to 3, characterized in that the glassy crystalline inorganic biomaterials (4) is a hydrolysis stable glass ceramic and / or ceramic and / or sintered glass ceramic whose chemical composition in each case the basic system PiOs-CaO-SiO ₂ with Additives corresponds. Fi. One-piece, cementless implantable acetabular cup according to claim 1 to 4, characterized in that as a polymer matrix (3) crosslinked polyurethanes or epoxy resins are used whose content of functional groups is at least 10% and whose glass transition temperature is above body temperature.