WO2011005126A1 - A joint endoprosthesis - Google Patents

A joint endoprosthesis Download PDF

Info

Publication number
WO2011005126A1
WO2011005126A1 PCT/PL2010/000055 PL2010000055W WO2011005126A1 WO 2011005126 A1 WO2011005126 A1 WO 2011005126A1 PL 2010000055 W PL2010000055 W PL 2010000055W WO 2011005126 A1 WO2011005126 A1 WO 2011005126A1
Authority
WO
WIPO (PCT)
Prior art keywords
joint endoprosthesis
cup
stem
endoprosthesis according
plastic
Prior art date
Application number
PCT/PL2010/000055
Other languages
French (fr)
Inventor
Leszek Olbrzymek
Original Assignee
Leszek Olbrzymek
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leszek Olbrzymek filed Critical Leszek Olbrzymek
Publication of WO2011005126A1 publication Critical patent/WO2011005126A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/32—Joints for the hip
    • A61F2/34—Acetabular cups
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/32—Joints for the hip
    • A61F2/36—Femoral heads ; Femoral endoprostheses
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A61F2/30965—Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30003—Material related properties of the prosthesis or of a coating on the prosthesis
    • A61F2002/30004—Material related properties of the prosthesis or of a coating on the prosthesis the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
    • A61F2002/30014—Material related properties of the prosthesis or of a coating on the prosthesis the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis differing in elasticity, stiffness or compressibility
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30003—Material related properties of the prosthesis or of a coating on the prosthesis
    • A61F2002/3006—Properties of materials and coating materials
    • A61F2002/30065—Properties of materials and coating materials thermoplastic, i.e. softening or fusing when heated, and hardening and becoming rigid again when cooled
    • A61F2002/30067—Coating or prosthesis-covering structure made of thermoplastic material
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30003—Material related properties of the prosthesis or of a coating on the prosthesis
    • A61F2002/3006—Properties of materials and coating materials
    • A61F2002/30069—Properties of materials and coating materials elastomeric
    • A61F2002/3007—Coating or prosthesis-covering structure made of elastic material, e.g. of elastomer
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30721—Accessories
    • A61F2002/30733—Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A61F2/30771—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth applied in original prostheses, e.g. holes or grooves
    • A61F2002/3084—Nanostructures
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A61F2/30907—Nets or sleeves applied to surface of prostheses or in cement
    • A61F2002/30909—Nets
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/32—Joints for the hip
    • A61F2/34—Acetabular cups
    • A61F2002/3469—Acetabular cups with non-radial inner bores or canals
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2250/0014—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
    • A61F2250/0018—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis differing in elasticity, stiffness or compressibility
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00389—The prosthesis being coated or covered with a particular material
    • A61F2310/0097—Coating or prosthesis-covering structure made of pharmaceutical products, e.g. antibiotics

Definitions

  • a JOINT ENDOPROSTHESIS TECHNICAL FIELD The present invention relates to the construction of an endoprosthesis for joints.
  • a hip joint endoprosthesis is known from Polish patent PL 111200, with a ball mounted on a stem neck via a plastic pad in the form of a ring separating the ball from the stem and functioning as a thrust bearing during rotation around the metal neck of the stem.
  • German patent DE2618763 discloses a hip joint endoprosthesis having a ball mounted on a stem neck via a plastic pad in the form of a cap separating the ball from the stem neck and dampening the pressure of the ball on the neck, which allows the use of a ball made of ceramic.
  • Publications RU2198624 (C2) and DE 4441695 (Al) present constructions utilizing materials causing an increase of the elasticity of the endoprosthesis.
  • implantable alloys used to make endoprosthesis stems and the outer surface of the cup result, in certain groups of patients, in allergic reactions causing postoperative complications.
  • the metal parts of the prostheses cause postoperative complications and toxic and allergic reactions in tissues surrounding the prostheses, as well in tissues of parenchymatous organs, resulting in side effects, which are often not recognized as related to the prosthesis.
  • Young's modulus of the metals forming the typical prostheses and that of the bone is found to induce many remedial operations necessitated by loosening of the cup in the hip joint or of the stem in the bone marrow canal, as well as by hip bone fractures.
  • the cup of endoprostheses often utilizes an insert in the frictional junction made of UHMWPE polyethylene (ultra high molecular weight polyethylene).
  • a low-friction material such as a high-molecular-weight polyethylene causes complications related to its relatively low abrasion resistance, and the wear products of the polyethylene cup are carried by bodily liquids outside the joint, causing inflammatory states.
  • the frictional elements of the ball-cup joint are known to be made of ceramic, which are biotolerable and highly resistant to abrasion, therefore the amount of wear products is minimal, the wear products are better tolerated by the organism and the durability of the kinematic joint of the endoprosthesis increases.
  • the object of the invention is to provide a joint endoprosthesis without at least one of the disadvantages of the prior art endoprostheses.
  • the object of the invention is a joint endoprosthesis comprising a cup, a ball and a stem, wherein the contact of bones with the endoprosthesis occurs via a layer of plastic, wherein the cup and the stem have a layered structure providing mechanical durability and elasticity approximate to the elasticity of the bones.
  • the layer of plastic contacting the bones provides biotoleration of the endoprosthesis, which facilitates the avoidance of allergic reactions, transfer to the body of ions of metals which may form the internal layers of the endoprosthesis, as well as protects the internal layers from corrosion.
  • the layered structure providing elasticity of the endoprosthesis approximate to the elasticity of bones facilitates the dampening of static and dynamic loads carried to the kinematic joint of the endoprosthesis. Therefore, the endoprosthesis is elastic, and therefore the incidence of loosening of the cup or stem, as well as resulting bone fractures, are avoided.
  • the plastic can be polyethylene.
  • the joint endoprosthesis according to the invention is particularly useful as a hip joint endoprosthesis, wherein large loads occur.
  • the elasticity of the cup and of the stem can be lower than the elasticity of bones.
  • the elasticity of the cup and of the stem expressed in terms of a Young's modulus value can be from 50% to 200% of the value of Young's modulus of the bones.
  • the elasticity of the cup and of the stem expressed in terms of a Young's modulus value can be lower than 50.
  • the cup can be made of ceramic and plastic.
  • the ball is made of ceramic and plastic or only of ceramic.
  • the stem can be made of plastic and metal or metal alloys.
  • the ball can be mounted in the cup and a conical seat of the ball can be mounted on a conical part of the stem.
  • the cup, the ball and the stem are selected from a series covering the gender, age, height, body weight and/or physical condition of the patient.
  • the cup can be made of ceramic covered by a layer of plastic, having a thickness and external shape depending on the series.
  • the thickness of the plastic layer covering the ceramic of the cup can be from 2 to 15 mm.
  • the ceramic of the cup can be a corundum ceramic having a wall thickness from 2 to 6 mm.
  • the stem may comprise a core made of metal or metal alloys covered by a layer of plastic having a thickness and external shape depending on the series.
  • the layer of plastic covering the core of the stem may have a thickness of at least 0.1 mm.
  • the ball may have the shape of a spherical shell made of corundum ceramic with a wall thickness from 2 to 6 mm.
  • the ball may have an internal part filled with a plastic, in which a conical seat is formed for mounting the stem.
  • the external extended surface of the cup and the extended surface of the stem can be configured to allow the ingrowth of bone tissue, and they may have a porous structure, comprise Velcro-like hooks or a partially moulded woven or non-woven fabric. This provides durable connection of the prosthesis with bones.
  • the layers of plastic can be formed in moulding forms, which provides for the repeatability of their shape and dimensions, as well as the repeatability of the mechanical and physicochemical parameters of the component parts of the endoprosthesis.
  • the layers of plastic comprise carbon nanotubes and/or carbon fibbers, which facilitates the local directional shaping of elasticity of these layers.
  • the layers of plastic may comprise silver nanoparticles, which provide bactericidal properties.
  • the advantage of the endoprosthesis according to the invention is that it provides a high mechanical durability and elasticity at the contact with the bones.
  • Fig. 1 shows a lateral section of the best embodiment of the joint endoprosthesis.
  • Fig. 2 shows an exploded view of the side cross-section of the best embodiment of the joint endoprosthesis.
  • Fig. 3 shows axonometric view of the cup of the endoprosthesis.
  • Fig. 4 shows axonometric view of the endoprosthesis.
  • Fig. 1 shows a lateral section of a second embodiment of the joint endoprosthesis.
  • Fig. 2 shows an exploded view of the lateral section of the second embodiment of the joint endoprosthesis.
  • the elastic joint endoprosthesis according to the best embodiment, as shown in Figs. 1-4, comprises an acetabulum cup 1 , a ceramic ball 2 and a stem 3.
  • the cup 1 is made of a ceramic part 4 and comprises a spherical surface 5 for positioning the ball 2.
  • the outer part of the ceramic cup 4 is covered by a layer 6 made of plastic, preferably polyethylene, having the form and thickness depending on the series.
  • the cover 6 of the cup 1 may, if necessary, comprise openings 7 for fixtures, preferably screws, facilitating the additional immobilization of the cup 1 in the pelvis bone.
  • the ceramic part and the cover may be separate.
  • the ball 2 made of ceramic 9 and having a spherical surface 8 for positioning in the cup 1 has an internal seat 11 in the form of a truncated cone for seating the stem 3.
  • the stem 3 of the endoprosthesis has a core 12 made of metal, metal alloys or other materials providing appropriate transmission of static and dynamic loads occurring in a given endoprosthesis.
  • the core 12 is covered by a layer 14 made of plastics, preferably polyethylene, having a thickness and an external shape depending on the series.
  • the cup 1 and the stem 3 have a layered structure, wherein the internal layer or layers provide mechanical durability and the external layer made of plastic provides elasticity.
  • the elasticity of the cup 1 and the stem 3 is approximate to the elasticity of bone, i.e. it does not substantially differ from the elasticity of bone such as in case of the endoprostheses having the cup 1 and the stem 3 made only of hard metals such as titanium with a Young's modulus exceeding 100.
  • the elasticity of the cup 1 and the stem 3 is lower than the elasticity of the bone.
  • the elasticity of the cup 1 and of the stem 3 expressed by Young's modulus is approximate to the Young's modulus of bone, namely from 50% to 200% of the average value of Young's modulus of the bone, which for most bones varies from 1 to 20.
  • the elasticity of the cup 1 and the bone 3 expressed as a Young's modulus is lower than 50.
  • the plastic layers 6, 14 may comprise, as a whole or in parts, carbon nanotubes or carbon fibers, preferably aligned directionally, for the local patterning of the elasticity of these layers.
  • the plastic layers 6, 14 may also comprise silver nanoparticles for bactericidal purposes.
  • the plastic layers 6, 14 may further comprise other materials.
  • the extended surface 15 of the cup 1 and the extended surface 16 of the stem 3 are shaped in such a way as to allow bone ingrowth, as shown in Fig. 4- 5. They may have a porous form, a hairy form, a form of Velcro-like hooks, or may comprise partially moulded-in woven or non-woven fabric.
  • the extended surface can be obtained by appropriately shaped forming moulds, mechanical working by means of numerically controlled machine tools, or connecting the surface with woven or non-woven fabric by means of a laser etc.
  • Figs. 5-6 comprises elements equivalent to elements of the embodiment shown in Fig. 1-4.
  • the equivalent elements have been indicated with the same reference numbers.
  • the joint endoprosthesis comprises an acetabulum cup 1 , a ball 2 and a stem 3.
  • the cup 1 has the shape of a spherical shell made of a ceramic 4, which forms a cap 5 for housing the ball 2.
  • the external part of the shell is covered by a layer of plastic, preferably polyethylene 6, having a thickness of 2- 15 mm, depending on the series of the endoprosthesis. Openings 7 for fittings, preferably, screws are made in the polyethylene part, which facilitate the further immobilization of the cup in the pelvic bone if necessary.
  • the ball 2 with surface 8 is a spherical shell made of ceramic 9, preferably corundum ceramic, having a wall thickness from 2 to 6 mm, filled with a layer of plastics 10, preferably polyethylene. It has an internal seat 11 having the shape of a truncated cone for mounting the stem 3.
  • the stem 3 of the endoprosthesis is made of metal or metal alloys 12, has a top part shaped like a truncated cone 13, making it possible to mount the ball 2 of the hip joint thereon.
  • the stem is covered by a layer of plastic 14, preferably polyethylene having a thickness not smaller than 0.1 mm.
  • the external shape of the stem 3 depends on the series.
  • the endoprosthesis according to the invention is shaped depending on the series, wherein the series covers gender, age, height, body weight and/or physical condition of the patient.
  • the endoprosthesis is useful for bone surgery of joint, in particular for implants of hip joints, knee joints, elbow joints, tarsal joints, acromioclavicular joints, as well as joints of the hand and foot.

Abstract

A joint endoprosthesis comprising a cup (1), a ball (2) and a stem (3), wherein the contact of bones with the endoprosthesis occurs via a layer of plastic (6, 14), wherein the cup (1) and the stem (3) have a layered structure with the mechanical durability and elasticity approximate to the elasticity of the bones.

Description

A JOINT ENDOPROSTHESIS TECHNICAL FIELD The present invention relates to the construction of an endoprosthesis for joints.
BACKGROUND ART A hip joint endoprosthesis is known from Polish patent PL 111200, with a ball mounted on a stem neck via a plastic pad in the form of a ring separating the ball from the stem and functioning as a thrust bearing during rotation around the metal neck of the stem.
German patent DE2618763 discloses a hip joint endoprosthesis having a ball mounted on a stem neck via a plastic pad in the form of a cap separating the ball from the stem neck and dampening the pressure of the ball on the neck, which allows the use of a ball made of ceramic.
Publications RU2198624 (C2) and DE 4441695 (Al) present constructions utilizing materials causing an increase of the elasticity of the endoprosthesis.
One of the common problems in the use of known endoprostheses is the use of metal elements touching bone.
The implantable alloys used to make endoprosthesis stems and the outer surface of the cup result, in certain groups of patients, in allergic reactions causing postoperative complications.
The contact of bodily liquids and tissues with metals causes their corrosion and penetration of metal ions to the body, which often results in inflammatory states and metalosis.
The metal parts of the prostheses cause postoperative complications and toxic and allergic reactions in tissues surrounding the prostheses, as well in tissues of parenchymatous organs, resulting in side effects, which are often not recognized as related to the prosthesis.
The excessive stiffness caused by a large difference between the
Young's modulus of the metals forming the typical prostheses and that of the bone is found to induce many remedial operations necessitated by loosening of the cup in the hip joint or of the stem in the bone marrow canal, as well as by hip bone fractures.
The cup of endoprostheses often utilizes an insert in the frictional junction made of UHMWPE polyethylene (ultra high molecular weight polyethylene).
The use of a low-friction material such as a high-molecular-weight polyethylene causes complications related to its relatively low abrasion resistance, and the wear products of the polyethylene cup are carried by bodily liquids outside the joint, causing inflammatory states.
The frictional elements of the ball-cup joint are known to be made of ceramic, which are biotolerable and highly resistant to abrasion, therefore the amount of wear products is minimal, the wear products are better tolerated by the organism and the durability of the kinematic joint of the endoprosthesis increases.
DISCLOSURE OF THE INVENTION
The object of the invention is to provide a joint endoprosthesis without at least one of the disadvantages of the prior art endoprostheses.
The object of the invention is a joint endoprosthesis comprising a cup, a ball and a stem, wherein the contact of bones with the endoprosthesis occurs via a layer of plastic, wherein the cup and the stem have a layered structure providing mechanical durability and elasticity approximate to the elasticity of the bones. The layer of plastic contacting the bones provides biotoleration of the endoprosthesis, which facilitates the avoidance of allergic reactions, transfer to the body of ions of metals which may form the internal layers of the endoprosthesis, as well as protects the internal layers from corrosion. Moreover, the layered structure providing elasticity of the endoprosthesis approximate to the elasticity of bones facilitates the dampening of static and dynamic loads carried to the kinematic joint of the endoprosthesis. Therefore, the endoprosthesis is elastic, and therefore the incidence of loosening of the cup or stem, as well as resulting bone fractures, are avoided.
The plastic can be polyethylene.
The joint endoprosthesis according to the invention is particularly useful as a hip joint endoprosthesis, wherein large loads occur.
The elasticity of the cup and of the stem can be lower than the elasticity of bones.
The elasticity of the cup and of the stem expressed in terms of a Young's modulus value can be from 50% to 200% of the value of Young's modulus of the bones.
The elasticity of the cup and of the stem expressed in terms of a Young's modulus value can be lower than 50.
The cup can be made of ceramic and plastic.
The ball is made of ceramic and plastic or only of ceramic.
The stem can be made of plastic and metal or metal alloys.
The ball can be mounted in the cup and a conical seat of the ball can be mounted on a conical part of the stem.
The cup, the ball and the stem are selected from a series covering the gender, age, height, body weight and/or physical condition of the patient. The cup can be made of ceramic covered by a layer of plastic, having a thickness and external shape depending on the series. The thickness of the plastic layer covering the ceramic of the cup can be from 2 to 15 mm. The ceramic of the cup can be a corundum ceramic having a wall thickness from 2 to 6 mm. The stem may comprise a core made of metal or metal alloys covered by a layer of plastic having a thickness and external shape depending on the series. The layer of plastic covering the core of the stem may have a thickness of at least 0.1 mm. The ball may have the shape of a spherical shell made of corundum ceramic with a wall thickness from 2 to 6 mm. The ball may have an internal part filled with a plastic, in which a conical seat is formed for mounting the stem.
The external extended surface of the cup and the extended surface of the stem can be configured to allow the ingrowth of bone tissue, and they may have a porous structure, comprise Velcro-like hooks or a partially moulded woven or non-woven fabric. This provides durable connection of the prosthesis with bones.
The layers of plastic can be formed in moulding forms, which provides for the repeatability of their shape and dimensions, as well as the repeatability of the mechanical and physicochemical parameters of the component parts of the endoprosthesis.
The layers of plastic comprise carbon nanotubes and/or carbon fibbers, which facilitates the local directional shaping of elasticity of these layers.
The layers of plastic may comprise silver nanoparticles, which provide bactericidal properties.
The advantage of the endoprosthesis according to the invention is that it provides a high mechanical durability and elasticity at the contact with the bones.
BRIEF DESCRIPTION OF DRAWINGS
The object of the invention is shown by means of embodiments in drawings, in which:
Fig. 1 shows a lateral section of the best embodiment of the joint endoprosthesis.
Fig. 2 shows an exploded view of the side cross-section of the best embodiment of the joint endoprosthesis.
Fig. 3 shows axonometric view of the cup of the endoprosthesis.
Fig. 4 shows axonometric view of the endoprosthesis. Fig. 1 shows a lateral section of a second embodiment of the joint endoprosthesis.
Fig. 2 shows an exploded view of the lateral section of the second embodiment of the joint endoprosthesis.
MODES FOR CARRYING OUT THE INVENTION
BEST MODE FOR CARRYING OUT THE INVENTION The elastic joint endoprosthesis according to the best embodiment, as shown in Figs. 1-4, comprises an acetabulum cup 1 , a ceramic ball 2 and a stem 3.
The cup 1 is made of a ceramic part 4 and comprises a spherical surface 5 for positioning the ball 2. The outer part of the ceramic cup 4 is covered by a layer 6 made of plastic, preferably polyethylene, having the form and thickness depending on the series.
The cover 6 of the cup 1 may, if necessary, comprise openings 7 for fixtures, preferably screws, facilitating the additional immobilization of the cup 1 in the pelvis bone. In such a case the ceramic part and the cover may be separate.
The ball 2 made of ceramic 9 and having a spherical surface 8 for positioning in the cup 1 has an internal seat 11 in the form of a truncated cone for seating the stem 3.
The stem 3 of the endoprosthesis has a core 12 made of metal, metal alloys or other materials providing appropriate transmission of static and dynamic loads occurring in a given endoprosthesis. The core 12 is covered by a layer 14 made of plastics, preferably polyethylene, having a thickness and an external shape depending on the series.
Thus, the cup 1 and the stem 3 have a layered structure, wherein the internal layer or layers provide mechanical durability and the external layer made of plastic provides elasticity. The elasticity of the cup 1 and the stem 3 is approximate to the elasticity of bone, i.e. it does not substantially differ from the elasticity of bone such as in case of the endoprostheses having the cup 1 and the stem 3 made only of hard metals such as titanium with a Young's modulus exceeding 100. Preferably, the elasticity of the cup 1 and the stem 3 is lower than the elasticity of the bone. Preferably, the elasticity of the cup 1 and of the stem 3 expressed by Young's modulus is approximate to the Young's modulus of bone, namely from 50% to 200% of the average value of Young's modulus of the bone, which for most bones varies from 1 to 20. Preferably, the elasticity of the cup 1 and the bone 3 expressed as a Young's modulus is lower than 50.
The plastic layers 6, 14 may comprise, as a whole or in parts, carbon nanotubes or carbon fibers, preferably aligned directionally, for the local patterning of the elasticity of these layers. The plastic layers 6, 14 may also comprise silver nanoparticles for bactericidal purposes. The plastic layers 6, 14 may further comprise other materials.
The extended surface 15 of the cup 1 and the extended surface 16 of the stem 3 are shaped in such a way as to allow bone ingrowth, as shown in Fig. 4- 5. They may have a porous form, a hairy form, a form of Velcro-like hooks, or may comprise partially moulded-in woven or non-woven fabric. The extended surface can be obtained by appropriately shaped forming moulds, mechanical working by means of numerically controlled machine tools, or connecting the surface with woven or non-woven fabric by means of a laser etc.
SECOND MODE FOR CARRYING OUT THE INVENTION The joint endoprosthesis according to the second embodiment, shown in
Figs. 5-6, comprises elements equivalent to elements of the embodiment shown in Fig. 1-4. The equivalent elements have been indicated with the same reference numbers.
The joint endoprosthesis comprises an acetabulum cup 1 , a ball 2 and a stem 3. The cup 1 has the shape of a spherical shell made of a ceramic 4, which forms a cap 5 for housing the ball 2. The external part of the shell is covered by a layer of plastic, preferably polyethylene 6, having a thickness of 2- 15 mm, depending on the series of the endoprosthesis. Openings 7 for fittings, preferably, screws are made in the polyethylene part, which facilitate the further immobilization of the cup in the pelvic bone if necessary. The ball 2 with surface 8 is a spherical shell made of ceramic 9, preferably corundum ceramic, having a wall thickness from 2 to 6 mm, filled with a layer of plastics 10, preferably polyethylene. It has an internal seat 11 having the shape of a truncated cone for mounting the stem 3.
The stem 3 of the endoprosthesis is made of metal or metal alloys 12, has a top part shaped like a truncated cone 13, making it possible to mount the ball 2 of the hip joint thereon. The stem is covered by a layer of plastic 14, preferably polyethylene having a thickness not smaller than 0.1 mm. The external shape of the stem 3 depends on the series. The endoprosthesis according to the invention is shaped depending on the series, wherein the series covers gender, age, height, body weight and/or physical condition of the patient. The endoprosthesis is useful for bone surgery of joint, in particular for implants of hip joints, knee joints, elbow joints, tarsal joints, acromioclavicular joints, as well as joints of the hand and foot.

Claims

1. A joint endoprosthesis comprising a cup (1), a ball (2) and a stem (3), characterized in that the contact of bones with the endoprosthesis occurs via a layer of plastic (6, 14), wherein the cup (1) and the stem (3) have a layered structure providing mechanical durability and elasticity approximate to the elasticity of the bones.
2. The joint endoprosthesis according to claim 1 , characterized in that the plastic is polyethylene.
3. The joint endoprosthesis according to any of claims 1-2, characterized in that it is a hip joint endoprosthesis.
4. The joint endoprosthesis according to any of claims 1-3, characterized in that the elasticity of the cup (1) and of the stem (3) is lower than the elasticity of bones.
5. The joint endoprosthesis according to any of claims 1-3, characterized in that the elasticity of the cup (1) and of the stem (3) expressed in terms of a
Young's modulus value is from 50% to 200% of the value of the Young's modulus of bones.
6. The joint endoprosthesis according to any of claims 1-3, characterized in that the elasticity of the cup (1) and of the stem (3) expressed in terms of a
Young's modulus value is lower than 50.
7. The joint endoprosthesis according to any of claims 1-6, characterized in that the cup (1) is made of ceramic and plastic.
8. The joint endoprosthesis according to any of claims 1-7, characterized in that the ball (2) is made of ceramic and plastic.
9. The joint endoprosthesis according to any of claims 1-7, characterized in that the ball (2) is made of a ceramic.
10. The joint endoprosthesis according to any of claims 1-9, characterized in that the stem (3) is made of plastic and metal or metal alloys.
11. The joint endoprosthesis according to any of claims 1-10, characterized in that the ball (2) is mounted in the cup (1) and the conical seat (11) of the ball (2) is mounted on a conical part (13) of the stem (3).
12. The joint endoprosthesis according to any of claims 1-11 , characterized in that the cup (1), the ball (2) and the stem (3) are selected from a series covering the gender, age, height, body weight and/or physical condition of the patient.
13. The joint endoprosthesis according to claim 12, characterized in that the cup (1) is made of a ceramic (4) covered by a layer of plastic (6), having a thickness and external shape dependent on the series.
14. The joint endoprosthesis according to claim 13, characterized in that the thickness of the plastic layer (6) covering the ceramic (4) of the cup (1) is from 2 to 15 mm.
15. The joint endoprosthesis according to any of claims 13 or 14, characterized in that the ceramic (4) of the cup (1) is a corundum ceramic having a wall thickness from 2 to 6 mm.
16. The joint endoprosthesis according to claim 12, characterized in that the stem (3) comprises a core (12) made of metal or metal alloys covered by a layer of plastic (14) having a thickness and external shape depending on the series.
17. The joint endoprosthesis according to claim 16, characterized in that the layer of plastic (14) covering the core (12) of the stem (3) has a thickness of at least 0.1 mm.
18. The joint endoprosthesis according to any of claims 1-17, characterized in that the ball (2) has a shape of a spherical shell made of corundum ceramic with a wall thickness from 2 to 6 mm.
19. The joint endoprosthesis according to any of claims 1-18, characterized in that the ball (2) has an internal part filled with a plastic (10), in which a conical seat (11) is formed for mounting the stem (3).
20. The joint endoprosthesis according to any of claims 1-19, characterized in that the external extended surface (15) of the cup (1) and the extended surface (16) of the stem (3) are configured to allow ingrowth of bone tissue.
21. The joint endoprosthesis according to claim 20, characterized in that the external extended surface (15) of the cup (1) and/or the extended surface (16) of the stem (3) have a porous structure.
22. The joint endoprosthesis according to claim 20, characterized in that the external extended surface (15) of the cup (1) and/or the extended surface (16) of the stem (3) comprise Velcro-like hooks.
23. The joint endoprosthesis according to claim 20, characterized in that the external extended surface (15) of the cup (1) and/or the extended surface (16) of the stem (3) comprise a partially moulded woven or non-woven fabric.
24. The joint endoprosthesis according to any of claims 1-23, characterized in that the layers of plastic (6, 14) are formed in moulding forms.
25. The joint endoprosthesis according to any of claims 1-24, characterized in that the layers of plastic (6, 14) comprise carbon nanotubes and/or carbon fibers.
26. The joint endoprosthesis according to any of claims 1-25, characterized in that the layers of plastic (6, 14) comprise silver nanoparticles.
PCT/PL2010/000055 2009-07-06 2010-07-05 A joint endoprosthesis WO2011005126A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PLP388465 2009-07-06
PL388465A PL219087B1 (en) 2009-07-06 2009-07-06 Flexible endoprosthesis, especially of the hip joint

Publications (1)

Publication Number Publication Date
WO2011005126A1 true WO2011005126A1 (en) 2011-01-13

Family

ID=43048864

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/PL2010/000055 WO2011005126A1 (en) 2009-07-06 2010-07-05 A joint endoprosthesis

Country Status (2)

Country Link
PL (1) PL219087B1 (en)
WO (1) WO2011005126A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102973335A (en) * 2012-12-24 2013-03-20 刘昌星 Novel artificial hip joint and manufacturing method thereof
EP2730254A1 (en) * 2012-06-18 2014-05-14 DePuy Synthes Products, LLC Dual modulus hip stem
JP2014176687A (en) * 2013-03-14 2014-09-25 Depuy Synthes Products Llc Femoral component for implantable hip prosthesis
CZ306816B6 (en) * 2014-12-22 2017-07-26 Beznoska, S.R.O. A joint implant and the method of its manufacture
WO2019076420A1 (en) * 2017-10-22 2019-04-25 Hafez Mahmoud Alm El Din A patient specific spacer

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2618763A1 (en) 1975-05-05 1976-11-18 Ceraver PROSTHESIS TO REPLACE A JOINT
PL111200B2 (en) 1978-11-20 1980-08-30 Endoprosthesis of hip joint
EP0019044A1 (en) * 1979-05-19 1980-11-26 Sigri Elektrographit Gmbh Stem part of a hip joint endoprosthesis and process for its manufacture
GB2216425A (en) * 1988-03-22 1989-10-11 Bristol Myers Co A bone implant
DE4441695A1 (en) 1994-11-23 1996-06-13 Gerd Hoermansdoerfer Anisotropically elastic hip joint endoprosthesis for implantation in narrow space of upper leg bone
RU2198624C2 (en) 2001-01-23 2003-02-20 Научно-исследовательский центр Татарстана "Восстановительная травматология и ортопедия" Hip joint implant
US20040102854A1 (en) * 2002-11-22 2004-05-27 Mengke Zhu Implantable orthopedic prosthesis with textured polymeric surfaces
US20050060040A1 (en) * 2003-09-15 2005-03-17 Benoist Girard Sas Prosthetic acetabular cup and prosthetic femoral joint incorporating such a cup

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2618763A1 (en) 1975-05-05 1976-11-18 Ceraver PROSTHESIS TO REPLACE A JOINT
PL111200B2 (en) 1978-11-20 1980-08-30 Endoprosthesis of hip joint
EP0019044A1 (en) * 1979-05-19 1980-11-26 Sigri Elektrographit Gmbh Stem part of a hip joint endoprosthesis and process for its manufacture
GB2216425A (en) * 1988-03-22 1989-10-11 Bristol Myers Co A bone implant
DE4441695A1 (en) 1994-11-23 1996-06-13 Gerd Hoermansdoerfer Anisotropically elastic hip joint endoprosthesis for implantation in narrow space of upper leg bone
RU2198624C2 (en) 2001-01-23 2003-02-20 Научно-исследовательский центр Татарстана "Восстановительная травматология и ортопедия" Hip joint implant
US20040102854A1 (en) * 2002-11-22 2004-05-27 Mengke Zhu Implantable orthopedic prosthesis with textured polymeric surfaces
US20050060040A1 (en) * 2003-09-15 2005-03-17 Benoist Girard Sas Prosthetic acetabular cup and prosthetic femoral joint incorporating such a cup

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10213310B2 (en) 2012-06-18 2019-02-26 DePuy Synthes Products, Inc. Dual modulus hip stem and method of making the same
EP2730254A1 (en) * 2012-06-18 2014-05-14 DePuy Synthes Products, LLC Dual modulus hip stem
US11020232B2 (en) 2012-06-18 2021-06-01 DePuy Synthes Products, Inc. Dual modulus hip stem and method of making the same
US8906108B2 (en) 2012-06-18 2014-12-09 DePuy Synthes Products, LLC Dual modulus hip stem and method of making the same
US9132013B2 (en) 2012-06-18 2015-09-15 DePuy Synthes Products, Inc. Dual modulus hip stem
CN102973335A (en) * 2012-12-24 2013-03-20 刘昌星 Novel artificial hip joint and manufacturing method thereof
JP2018198958A (en) * 2013-03-14 2018-12-20 デピュイ・シンセス・プロダクツ・インコーポレイテッド Femoral component for implantable hip prosthesis
US10213314B2 (en) 2013-03-14 2019-02-26 DePuy Synthes Products, Inc. Femoral component for an implantable hip prosthesis
US9271839B2 (en) 2013-03-14 2016-03-01 DePuy Synthes Products, Inc. Femoral component for an implantable hip prosthesis
US9717597B2 (en) 2013-03-14 2017-08-01 DePuy Synthes Products, Inc. Femoral component for an implantable hip prosthesis
JP2014176687A (en) * 2013-03-14 2014-09-25 Depuy Synthes Products Llc Femoral component for implantable hip prosthesis
US11058543B2 (en) 2013-03-14 2021-07-13 DePuy Synthes Products, Inc. Femoral component for an implantable hip prosthesis and method of making same
CZ306816B6 (en) * 2014-12-22 2017-07-26 Beznoska, S.R.O. A joint implant and the method of its manufacture
WO2019076420A1 (en) * 2017-10-22 2019-04-25 Hafez Mahmoud Alm El Din A patient specific spacer

Also Published As

Publication number Publication date
PL388465A1 (en) 2011-01-17
PL219087B1 (en) 2015-03-31

Similar Documents

Publication Publication Date Title
US8979935B2 (en) Joint space interpositional prosthetic device with internal bearing surfaces
US10272177B2 (en) Joint replacement or joint resurfacing devices, systems and methods
EP0803234B1 (en) Methods of manufacturing an acetabular cup
JP5596686B2 (en) Orthopedic graft with spatially varying porosity
US20200360146A1 (en) Hip Joint Device
CN111297519B (en) Metal hip joint prosthesis with porous layer structure and preparation method thereof
WO2011005126A1 (en) A joint endoprosthesis
JP2010527706A (en) Acetabular prosthesis
CN104042361A (en) Femoral Component For An Implantable Hip Prosthesis
CN105030381A (en) Artificial acetabular cup
US20100262257A1 (en) Joint Prosthesis for a Human Body and Associated Method
US20230023358A1 (en) Coating for an implant
US11357636B2 (en) Magnetic artificial joint
US20090248168A1 (en) Prosthesis
CN109106474A (en) A kind of orthopaedics implant
CN211156484U (en) Femoral head prosthesis, femoral prosthesis component and hip joint component
CN209048363U (en) A kind of orthopaedics implant
US9848986B2 (en) Joint replacement component with integrated fixation pads
CN215019765U (en) Acetabular cup
US20160367374A1 (en) Implants
AU772302B2 (en) Polyethylene hip joint prosthesis with extended range of motion
JP4580276B2 (en) Hip prostheses and cups for hip prostheses
CN117257528A (en) Acetabular prosthesis, method for producing an acetabular prosthesis and joint prosthesis
GB2408938A (en) Improved bearing compound of sandwich construction with layered stiffness for use in joint prosthesis
CN117257529A (en) Tantalum coating hip joint prosthesis system

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10752446

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10752446

Country of ref document: EP

Kind code of ref document: A1