Apparatus and related methods for coating implants

Abstract

The present invention provides an apparatus for coating elongated implants, a system comprising such an apparatus, a method for using the apparatus, and a method for coating elongated implants. [Solution] The apparatus 10 for coating an elongated implant 5 includes a reservoir 12 for holding a coating agent 8 and a lower part 15 connected to or connectable to the reservoir and having an opening 16. The material forming the opening is rubber-elastic and functions as a wiper for wiping away excess coating agent.

Description

Technical Field

[0001] The present invention relates to an apparatus for coating an elongated implant, a system comprising such an apparatus, the use of the apparatus, and a method for coating an elongated implant.

[0002] Intramedullary nails and bone plates are used, for example, in trauma surgery to treat fractures. This occurs particularly in the case of fractures of long bones such as the femur (thigh bone), tibia (shin bone), or humerus (upper arm bone). After such a procedure, infections of the surrounding bone and / or soft tissue can occur due to bacteria such as Staphylococcus aureus or Staphylococcus epidermidis. This requires surgical debridement, during which the infected tissue is removed. In addition, systemic antibacterial agents and / or local anti-infective agents are used to combat the infection on a targeted basis.

[0003] This is desirable, for example, when mechanical stabilization of the fractured bone tissue is still possible through an elongated implant such as an intramedullary nail and / or a bone plate after surgical debridement, and these can simultaneously release a local anti-infective agent to locally suppress the microorganisms remaining in the tissue excised from the wound surface.

[0004] The use of intramedullary nails with antimicrobial coatings of polymethyl methacrylate bone cement is known (N. Walter et al.: "Individual and commercially available antimicrobial coatings for intramedullary nails for the treatment of infected long bone non-unions - a systematic review", Injury2022, DOI:10.1016 / j.injury.2022.05.008). The antimicrobial agent from the bone cement is dissolved from the coating by aqueous bodily fluids such as wound secretions and blood, resulting in a locally high concentration of the antimicrobial agent. In combination with systemic antimicrobial agents, this can reduce the number of bacteria that may remain after debridement.

[0005] Furthermore, it is desirable to create such coatings during surgery. This would allow for the incorporation of antiinfective agents precisely matched to the present bacteria into the coating material. To date, in-surgery coating has been performed by preparing bone cement containing the necessary antiinfective agents and manually forming a layer of bone cement around the intramedullary nail to be coated. Achieving a uniform layer thickness along the entire length of the intramedullary nail is extremely difficult. Often, the coated nail has a cross-section that is at least partially too large, making it impossible to implant it into the debridemented bone. Due to the strong adhesion of polymethyl methacrylate bone cement to the metal surface, the applied bone cement can no longer be removed from the surface of the intramedullary nail even after a short time. In some areas, the layer thickness may be too thin, resulting in insufficient amounts of available antiinfective agent, at least locally.

[0006] U.S. Patent Application Publication No. 2007 / 0134287(A1) describes an antimicrobial coating solution comprising an antimicrobial agent dissolved in a readily evaporating solvent. U.S. Patent Application Publication No. 11517650(B2) describes a similar coating solution in which the antimicrobial agent is dissolved in a rapidly or moderately evaporating solvent, and energy is supplied by ultrasound to accelerate the dissolution process. European Patent Application Publication No. 1243259(B1) discloses a coating comprising polymethyl methacrylate and a hydrophilic polymer in which the antimicrobial agent is suspended. A similar solution is described in European Patent Application Publication No. 1112095(B1). In this document, the suspension is applied to the implant surface, the solvent evaporates, and a D,L-polylactide film with immobilized antimicrobial agent particles remains.

[0007] The features described above can be combined with various aspects of the present invention as desired.

[0008] The objective of the present invention is to provide an elongated implant having a specified coating in a simple manner.

[0009] This objective is achieved by the apparatus described in claim 1, as well as by the systems, uses, and methods described in additional independent claims. Advantageous embodiments are provided in the dependent claims.

[0010] To achieve this objective, a device for coating elongated implants is used. This device includes a reservoir for holding the coating agent, along with a lower section. In particular, the lower section is connected to or can be connected to the reservoir. The lower section includes an opening. The material forming the opening is rubber-elastic and functions as a wiper for wiping away excess coating agent.

[0011] During intended use, the reservoir is located above the bottom. The coating agent is placed inside the reservoir. The elongated implant is moved downward, typically along the central axis of the device, through the reservoir and opening. The implant can be moistened with the coating agent in the reservoir and / or within the area of ​​the base portion of the device. A wiper removes excess coating agent from the surface of the implant. In this way, a uniform coating is possible. The area forming the opening conforms to the shape of the implant and thus allows for uniform wiping. The coating can then be cured within a few minutes.

[0012] This device is easy to manufacture, cost-effective, and easy to use, enabling the reproducible creation of specified coatings. Because application is simple and rapid, it can even be performed during surgery, resulting in the use of coatings with individually tailored active ingredients.

[0013] The coating agent may include, for example, bone cement or polymer. Alternatively, or additionally, the coating agent may include one or more active ingredients, such as anti-infective agents. The active ingredients may be dissolved or suspended in one or more polymers. The implant may be, for example, an intramedullary nail or a bone splint.

[0014] The reservoir is open, in particular, on the side opposite the top or opening. In this way, the implant and / or coating can be inserted into or added to the reservoir from above.

[0015] The reservoir may include a rotationally symmetric base shape. "Rotationally symmetric base shape" means that the underlying shape is rotationally symmetric. Attachments, additional parts, recesses, holes, etc., may exist on or within this base shape, resulting in the actual shape deviating from the rotationally symmetric shape. Other deviations from the rotationally symmetric shape may include being thicker or flatter. The reservoir encloses a cavity for holding the coating material.

[0016] The lower part is the area of ​​the device that forms the opening. The opening helps to remove the implant from the device after coating. The walls of the opening can be designed as a wiper. The wiper typically includes an edge that helps to wipe and may also be called a wiper lip. The wiper is designed so that slightly viscous liquids cannot flow between the wiper and the implant.

[0017] The lower section is mechanically connected to or connectable to a reservoir. Manual and / or reversible connections may be provided. These connections are particularly liquid-tight. The lower section may be indirectly connected to or connectable to a reservoir.

[0018] The material forming the opening is made of a rubber-elastic material. In particular, the lower part is made of a rubber-elastic material, at least partially. This allows for elastic deformation of the opening. Typically, rubber elasticity is such that a body with a diameter 10% larger than the diameter of the opening can pass through the opening without damage. This preferably also applies to diameters 20% or 30% larger. In particular, the opening with the wiper is slightly smaller than the implant being coated. This prevents uncontrolled flow of the coating agent.

[0019] Rubber elasticity also allows for variable elongation along the longitudinal axis, enabling the coating of implants with variable diameters, for example. Such implants are actually used frequently. Stretching of the material forming the opening allows for a defined coating.

[0020] An elongated implant in the sense of the present invention is an implant in which the elongation in the main elongation direction is at least three times greater than the elongation in all directions transverse to the main elongation direction. The cross-section of the implant can be, for example, circular, elliptical, or polygonal. A polygonal cross-section has at least three angles. The implant may be rod-shaped.

[0021] In one embodiment, the lower part includes a hollow conical portion. In particular, the conical portion is made partially or entirely of a rubber elastic material.

[0022] Therefore, the device is constructed from two parts. The upper part is defined by a reservoir, and the lower part includes a conical portion. During intended use, the reservoir is typically located above the conical portion. The coating agent can be placed in the reservoir and / or within the conical portion. The implant can come into contact with the coating agent in the reservoir and / or within the conical portion. The conical portion can conform to the shape of the implant, thus enabling particularly effective coating.

[0023] The lower portion can connect to the opening of a reservoir and / or function to coat the implant. The lower portion and / or conical portion typically define a cavity that can hold the coating material and / or allow the implant to move. The reservoir cavity connects to the cavity in the lower portion or the conical portion. In particular, the opening is located on the side of the conical portion facing away from the reservoir.

[0024] The conical portion includes, in particular, a conical outer surface. The inner surface can also be conical. The wall thickness may be constant. In particular, the central axis of the conical portion extends from a larger first side to a smaller second side. The conical portion can include rotational symmetry, rotational symmetry (about an axis), mirror symmetry, and / or an elongated basic shape. The central axis can coincide with the axis of rotation, the axis of symmetry, and / or the central axis of the plane of symmetry. The conical portion is particularly elongated. Therefore, the longitudinal axis of the conical portion can coincide with the central axis. The conical portion can include the shape of a hollow truncated cone. The opening is located, in particular, on the side of the conical portion facing away from the smaller second side and / or the reservoir.

[0025] The angle between the outside of the conical part and the central axis of the conical part is typically at most 45°, preferably at most 35°, particularly at most 25°. Particularly preferably, the angle is at most 20°, particularly at most 15°. This angle is typically at least 2°, particularly at least 5°.

[0026] Preferably, the lower part is mechanically connected to or connectable to the reservoir. A manual and / or reversible connection may be provided. This connection is particularly liquid-tight.

[0027] Particularly, the conical part is made at least partially or entirely of an elastomeric material. This enables elastic deformation.

[0028] In one embodiment, the material forming the opening, the material of the lower part, or the material of the conical part is a material having a Shore A hardness of at least 30, preferably at least 50. Particularly, the Shore A hardness of the material is at most 80.

[0029] In one embodiment, the larger first side of the conical part faces the reservoir, and the smaller second side of the conical part faces away from the reservoir. Particularly, the opening is located on the second side.

[0030] The conical part particularly includes two sides at opposite positions with respect to the longitudinal axis and / or the central axis of the conical part. The larger side is larger than the smaller side. The first side is particularly connected to or connectable to the reservoir. The wiper can be arranged on the second side. The wiper is particularly located at the end of the conical part facing away from the reservoir or the free end.

[0031] The first side includes an opening continuously connected to the reservoir. The extension of this opening, for example, the free diameter, corresponds at least to the lateral extension of the implant to be coated, for example, the outer diameter.

[0032] In one embodiment, the reservoir includes a first connection region, and the lower part includes a corresponding second connection region. In particular, the first and second connection regions can be mechanically reversibly connected to each other.

[0033] Therefore, the lower and upper parts can be connected reversibly. "Reversible" means that the connection can be disconnected without causing damage. In particular, the connection can be manually locked and / or disconnected. For example, the connection area is configured as a corresponding thread, as a corresponding part of a bayonet lock, or as a corresponding part of a plug connection.

[0034] This allows for easy replacement of the cone portion or installation of the desired cone portion. Different cone portions can be provided for different implants. For example, a cone portion for an implant with a circular cross-section may include an opening with a circular base shape, and / or a cone portion for a flat implant may include an opening with an elongated base shape. The actual shape may differ from the base shape, for example, due to spacers. However, on the side facing the reservoir, different cone portions may have the same or similar shape.

[0035] In one embodiment, the opening exhibits a basic circular or slit shape. This allows for particularly uniform coating of intramedullary nails with a circular cross-section or bone splints with a flat cross-section. The actual shape of the opening may differ from the basic shape, for example, due to spacers.

[0036] In one embodiment, a spacer is placed on the wiper to ensure a distance between the wiper and the elongated implant to be coated. The spacer ensures a defined distance between the wiper and the implant as the implant moves through the opening. This allows for a coating with a uniform thickness.

[0037] Since the spacer is in direct contact with the implant, there is little to no coating material at these contact points. In this case, a longitudinal strip without coating is formed on the surface of the implant. Some coating materials, such as low-viscosity bone cement, have been shown to flow into the uncoated areas after coating, thus achieving a uniform coating.

[0038] In particular, the spacers protrude radially inward. Preferably, the spacers are designed so that a large portion of the implant surface is coated. Therefore, the proportion of the implant surface to which the coating is applied is at least the same as, and preferably larger than, the proportion of the surface in contact with the spacer. To ensure effective delivery of the active ingredient, it has been shown that coating at least 50% of the surface is sufficient. Preferably, the spacers are arranged at equal intervals to ensure uniform application of the coating.

[0039] The spacer is positioned particularly on the conical portion and / or on the inner surface of the wiper. In this way, a distance can be maintained between the wiper and the implant when wiping off the coating agent.

[0040] In particular, the spacers are distributed in the longitudinal direction and preferably arranged at equal intervals. The spacers can be designed, for example, to be pin-shaped or rib-shaped.

[0041] The spacer is fixed or molded into the conical region. In particular, the spacer is made of a material with higher hardness than the rubber-elastic material of the conical portion.

[0042] In the case of a slit-shaped opening, only the longer side can be coated when viewed in cross-section. In this case, no spacers are placed on the narrower side. Alternatively, or additionally, only one side may be coated. In this case, no spacers are placed on the uncoated side, and as a result, the coating agent is wiped off completely or almost completely.

[0043] Spacers are typically not made of rubber-elastic material that forms the opening. Spacers are typically made of a harder and / or stronger material. Rubber-elastic deflection of the spacer is undesirable. In one embodiment, the spacer is made of plastic, preferably thermoplastic.

[0044] The spacer can be fixed to the conical portion. Alternatively, or additionally, the spacer can be fixed to a separate structure, particularly the lower part. In this case, the spacer may be in contact with the conical portion.

[0045] In one embodiment, the spacers are arranged to be uniformly distributed in the circumferential direction. This allows for uniform application of the coating. In particular, at least three spacers, preferably at least four or at least five spacers, are present in the circumferential direction. In one embodiment, six or more spacers are arranged in the circumferential direction.

[0046] In one embodiment, the spacer is configured to be rib-shaped. "Rib-shaped" means a shape in which the first extension direction is many times longer than the second and third extension directions, and both the second and third extension directions are perpendicular to the first extension direction and to each other. For example, the first extension direction may be at least 3 times, preferably at least 5 times, and particularly preferably at least 8 or 10 times, larger than the second and / or third extension directions. The rib-shaped spacer can be placed in a conical portion.

[0047] Preferably, the rib-shaped spacer extends in the longitudinal direction of the device and / or the conical portion.

[0048] In one embodiment, the spacer extends at an angle of less than 30° with respect to the central axis of the device. However, due to the conical shape of the conical portion, the spacer does not extend precisely parallel to the central axis or outer wall of the conical portion, but rather extends at an angle to it, as well as to the outside of the conical portion. The angle between the longitudinal axis of the rib-shaped spacer and the central axis of the conical portion can, in principle, be at most 45°, preferably at most 35°, and particularly at most 25°. Particularly preferably, the angle is at most 20°, and particularly at most 15°. This angle is typically at least 2°, and particularly at least 5°.

[0049] Due to its elongated shape, the spacer cannot bend longitudinally. This ensures that the distance is maintained in a particularly safe manner as the implant moves along the central axis through the device. The rib-shaped spacer allows for the creation of a coating with a constant thickness, even if the material forming the opening is stretched due to a change in the cross-section of the implant.

[0050] In one embodiment, the rib-shaped spacer is shaped to contact up to 35%, preferably up to 25%, and particularly preferably up to 15% of the outer circumference of the implant.

[0051] In one embodiment, the rib-shaped spacer has a length of at least 3 mm, preferably at least 5 mm, and / or up to 20 mm, preferably up to 15 mm, along its main elongation direction. In one embodiment, the rib-shaped spacer has a width of at least 0.5 mm, particularly at least 1.0 mm, and / or up to 5.0 mm, particularly up to 3.0 mm, in the direction lateral to its main elongation direction. This applies to both directions transverse to the main elongation direction. The two directions may include the same or different elongation. The elongation of the spacer in the radial direction defines the layer thickness. In particular, all spacers have the same elongation at least in the radial direction, and preferably in all other directions as well.

[0052] In one embodiment, the rib-shaped spacer includes a cross-section having a contact side and a free side. In particular, the first width of the contact side spacer is greater in at least some areas than the second width of the free side spacer, measured parallel to the first width. The contact side can contact and fix to the conical portion. The free side protrudes freely inward and functions to contact the implant.

[0053] In other words, the spacer includes a lateral extension measured perpendicular to the longitudinal extension, and the lateral extension is wider than the free end region in at least some areas, in the region of the inner wall of the conical portion.

[0054] In this way, the contact area between the implant and the spacer is minimized. As a result, the uncoated area on the implant surface is reduced. In this manner, a particularly uniform coating can be achieved.

[0055] In one embodiment, the rib-shaped spacer includes triangular, trapezoidal, rectangular, or hemispherical cross-sections. Such shapes of spacers minimize the uncoated area of ​​the implant, are easy to manufacture, and are particularly dimensionally stable. The corners of the cross-sections may be rounded.

[0056] In one embodiment, one end of a rib-shaped spacer facing the reservoir is designed to be rounded. This simplifies implant insertion and ensures, in particular, a reproducible coating.

[0057] In one embodiment, at least one side of the reservoir facing away from the lower and / or conical portion is designed as a cylinder. In particular, the device further includes a piston corresponding to the cylinder for pressing the coating agent. The piston is typically a separate component.

[0058] The cylinder and piston are shaped accordingly. The piston can typically be manually moved within the cylinder to press the coating material from the reservoir toward the conical portion and / or opening. This is particularly advantageous in the case of viscous or highly viscous bone cement that flows only slowly. In this case, it is possible that the bone cement adhering to the implant may be discharged downward from the conical portion faster than the bone cement flows out of the reservoir. The ability to push the bone cement downward prevents coating defects due to bone cement loss and ensures a rapid and uniform coating.

[0059] Part or all of the reservoir may be configured as a cylinder. The cylinder does not have to be circular and can have any cross-sectional area. However, circular cylinders are particularly easy to manufacture. In particular, the piston and cylinder share a common central axis, and relative motion occurs along this central axis. The piston may have a U-shaped cross-section. Alternatively, the piston may be designed as, for example, a convex hollow body.

[0060] In one embodiment, the piston may include a central opening into which an implant can be inserted. The opening may be partially or completely closed with a cover, particularly a rubber elastic cover. As a rule, the plunger is used with high-viscosity bone cement so that the plunger can push the bone cement downward despite the presence of the opening. A wiper may be positioned in the area of ​​the opening.

[0061] The reservoir, lower section, and / or conical section are made of plastic and / or rubber. Preferably, the reservoir and lower section, except for the conical section, are made of plastic, and / or the conical section is made of a rubber-elastic material such as rubber.

[0062] A further aspect of the present invention is a system for coating particularly elongated implants. The system comprises an apparatus according to the present invention. The system further comprises an additional lower section having an opening, wherein the material forming the opening is rubber-elastic and functions as a wiper. The additional lower section includes a second connection section corresponding to a first connection section of the apparatus and which can be mechanically and reversibly connected to the first connection section.

[0063] In this way, the desired layer thickness can be set before coating by selecting and connecting the desired conical portion. The system may also be called a kit. In particular, the components of the system are packaged together so that the appropriate conical portion, i.e., the lower part of the device, can be selected and used during surgery. In other words, the system includes an upper part and at least two lower parts. There may be several additional lower parts, and each opening in each lower part exhibits a different shape and / or size.

[0064] All the features, advantages, and embodiments of the apparatus, use, and method described above can also be applied to systems, and vice versa.

[0065] In one embodiment, the system further includes components for producing bone cement. In particular, these components are such that bone cement can be produced without the addition of additional materials. For example, the components include polymethyl methacrylate bone cement powder and monomer liquid. Specifically, each component is contained in separate packaging. Optional active ingredients typically need to be added.

[0066] In one embodiment, the system further comprises a mixing device for mixing bone cement. The mixing device may comprise a mixing bowl and one or more mixing utensils, such as one or more spatulas. Alternatively, or additionally, the mixing device may comprise a mixing system with, for example, a cartridge having an integrated or attached mixing rod.

[0067] A further aspect of the present invention is the use of the apparatus according to the present invention for coating elongated implants. All the features, advantages and embodiments of the apparatus, systems and methods described above can also be applied to the use, and vice versa.

[0068] The implants are, in particular, surgical implants such as locked or unlocked intramedullary nails or osteosynthesis plates. Implants may be made of, for example, titanium, titanium alloys, steel, composite materials, and / or one or more plastics, or may contain one or more of these materials. The implants to be coated may, in principle, be any other elongated implants such as implantable electrodes, tubular artificial blood vessels, or plastic tubes. In principle, other elongated objects may also be coated.

[0069] In particular, these are paste-like coating agents, such as bone cement, such as polymethyl methacrylate bone cement coatings. Polymethyl methacrylate bone cement is prepared by mixing polymethyl methacrylate bone cement powder with a methyl methacrylate monomer liquid, and spontaneously hardens within minutes by the radical polymerization of methyl methacrylate. Specifically, the coating contains at least one pharmaceutical active ingredient suspended or dissolved therein.

[0070] Alternatively, or in addition, polymers or polymer solutions can be used. Suitable materials for this purpose include polylactides, polymethyl methacrylates, polyvinyl acetate, and / or polyvinyl chloride, which are soluble in volatile solvents such as acetone and / or chloroform. The volatile solvent can evaporate from the polymer solution after coating, leaving an adhesive polymer film on the implant surface.

[0071] In particular, the coating agent contains at least one pharmaceutical active ingredient, which is preferably an anti-infective agent, such as gentamicin, tobramycin, amikacin, vancomycin, dalbavancin, teicoplanin, daptomycin, clindamycin, meropenem, colistin, ampicillin, amoxicillin, ofloxacin, levofloxacin, moxifloxacin, ciprofloxacin, amphotericin B, micafungin, fluconazole, or any mixture of at least two of the above. The coated implant is suitable for local release of the active ingredient in addition to its actual, usually mechanical, function.

[0072] A further aspect of the present invention is a method for coating a longitudinal implant using a device. The method comprises providing a device having a reservoir in which a coating agent is held. The method further comprises moving an elongated implant through an opening at the bottom of the device through the coating agent. Excess coating agent is wiped away from the implant by a wiper of the device.

[0073] Movement is carried out in one direction, particularly from the reservoir to the conical portion. Movement of the implant through the coating agent can be carried out, for example, within the reservoir and / or within the lower portion. Wiping is carried out, particularly when leaving the lower portion, preferably through an opening that includes or forms a wiper. The implant may be longer or shorter than the device. The uncoated portion of the implant may be located on the coating agent, while excess coating agent is wiped away from the already coated portion of the implant. The implant may pass through the entire device. In particular, the device is the device according to the present invention.

[0074] In principle, movement is relative motion. It is irrelevant whether the implant, the device, or components of both are being moved. For simplicity, we will simply refer to it as "moving" or "moving the implant." All of the aforementioned relative motion possibilities are always intended.

[0075] If the implant has a variable cross-section, the thinner side of the implant is coated first. Then, the implant is moved downward in the device, with the thinner side first.

[0076] In particular, the implant is first moved so that the first end of the implant is positioned in the region of the second opening located in the conical portion, especially at the base. The first end may be pushed through the second opening. Subsequently, the coating agent is filled, in particular, into the reservoir and / or conical portion. In particular, the device is positioned so that the reservoir is located in the center above the conical portion. Following this sequence effectively prevents the coating agent from penetrating into the internal cavity of the implant. Behind this, intramedullary nails and other implants may be designed as hollow bodies with openings at the ends. In these cases, penetration of the coating agent into the cavity is usually undesirable.

[0077] When an implant is placed in the area of ​​an opening, the material forming the opening may be stretched due to contact with the implant.

[0078] Due to gravity, the coating agent can sink downwards within the conical portion. The implant can then be moistened there. The coating agent then adheres to the surface of the implant.

[0079] The implant can be moved downward relative to the device, for example, by pushing the upper end and / or pulling the lower end. Preferably, the entire implant is moved through the device so that each region of the implant contacts the wiper at least once. Meanwhile, the coating agent can flow downward from the reservoir to the conical portion. This can be assisted by pressing the piston.

[0080] For example, spacers such as rib-shaped spacers can come into contact with the implant and thus maintain the distance between the wiper and the implant surface. In this way, a defined, uniform layer thickness corresponding to the radial extension of the spacer can be achieved, at least in the region between the spacers. Excess coating agent is wiped away and remains on the conical portion.

[0081] In particular, post-treatment of the coating is performed to produce the final solid coating. This can be done, for example, by curing the coating agent or by evaporating and / or vaporizing the solvent.

[0082] In one embodiment, the removal of the coating agent is performed, for example, by inserting a pin or plunger through the opening of the implant. This is preferably done before post-treatment.

[0083] Exemplary embodiments of the present invention are also described in more detail below with reference to the drawings. Features of the exemplary embodiments may be individually or combined with multiple claimed subject matter unless otherwise specified. The scope of claimed protection is not limited to the exemplary embodiments. [Brief explanation of the drawing]

[0084] [Figure 1] A perspective cross-sectional view of the device is shown. [Figure 2] Two cross-sectional views of the device are shown. [Figure 3] This shows a cross-sectional view of the device in use. [Figure 4] This shows a cross-sectional view of the device in use. [Figure 5] This shows a coated implant. [Figure 6] The exploded view of the device is shown. [Figure 7] This shows a cross-sectional view of the device in use. [Figure 8] This shows a cross-section of a coated implant. [Figure 9] This shows a cross-section of a coated implant. [Figure 10] A cross-sectional view of the spacer is shown.

[0085] Figure 1 shows an apparatus 10 according to the present invention for coating elongated implants. The apparatus 10 includes a reservoir 12, shown in the center here, for holding the coating agent. The reservoir 12 has a circular cylindrical or rotationally symmetric basic shape and is open at the top and bottom. The reservoir 12 includes a first connection area 31 on the bottom side, which has the shape of a female thread.

[0086] Here, the lower 15, consisting of two components 25, 26 that cannot be nondestructively separated from each other, is located below the reservoir 12. The roughly annular upper component 25 includes a second connector 32 in the shape of a male thread that can be screwed into the female thread of the reservoir 12. The upper component 25 can be made of relatively rigid plastic. The lower component 26 of the lower 15 is configured as a hollow conical portion 20 exhibiting the basic shape of a truncated cone. The lower component 26 can be made of a rubber-elastic material. The larger first side 21 of the conical portion 20 connects to the upper component 25. The smaller second side 22 of the conical portion 20 faces downward and forms an opening 16 of the device. The opening 16 exhibits a basic circular shape. The exact shape of the opening 16 deviates from circular due to a spacer 40 described later. The material 17 forming the opening 16 is rubber-elastic and functions as a wiper 18 for wiping. In particular, the entire lower component 26 and / or the entire conical portion 20 are rubber-elastic. The use of the device 10 is shown in Figures 3 and 4. The upper component 25 may include the spacer 40, as shown in Figure 2, which will be described below.

[0087] A spacer 40 is positioned in the lower part 15, i.e., the conical portion 20, to ensure a specified distance between the implant surface and the wiper 18. The spacer 40 is configured as a substantially vertical or aligned rib along the central axis A or longitudinal axis of the device 10 and / or the conical portion 20. This prevents the spacer 40 from bending in the vertical direction, also known as the z direction.

[0088] The upper end 44 of the spacer facing the reservoir 12 is designed to be rounded. In this way, undesirable blocking of the implant during its downward movement can be prevented.

[0089] The embodiment shown herein shows three spacers 40 on one side of the device 10, i.e., a total of six spacers 40. The spacers 40 are uniformly distributed in the circumferential direction.

[0090] The apparatus optionally further includes a piston 52. In this case, the upper part of the reservoir 12 is cylindrical, in this case a circular cylinder. The piston 52 fits snugly into the upper part of the reservoir 12 and functions to press the high-viscosity coating agent downward into the conical portion 20. The piston 52 includes an opening 54 that is at least partially closed by a rubber elastic cover 55, in particular a rubber elastic cover having star-shaped slits.

[0091] Figure 2 shows the longitudinal section of the apparatus 10 at the top and the transverse section at the bottom, indicating the viewing direction in the longitudinal section. Apparatus 10 can correspond entirely or partially to the apparatus 10 in Figure 1. In the region of the conical section 20, cuts extend on both sides through each spacer 40. The angle α between the longitudinal axis of the rib-shaped spacer 40 and the central axis A of the apparatus 10, which extends perpendicularly here, corresponds to the angle of the inner surface of the conical section 20 with respect to the central axis A of the apparatus.

[0092] In the lower diagram, it can be seen that the opening 16, which has a basic circular shape, is shaped into a star shape by the spacer 40.

[0093] Figure 3 shows the use of the device 10. The implant 5, in particular the intramedullary nail, is positioned roughly vertically in the device. For example, a coating agent 8, such as bone cement containing the active ingredient, is introduced into the reservoir 12 and / or lower part 15 from above, for example, using a syringe 7. At this time, the lower end of the implant 5 is already in contact with the inner surface of the spacer 40 and / or conical portion 20, or has already been pushed slightly through the opening 16. In this way, the coating agent 8 is prevented from entering the hollow interior of the implant 5.

[0094] Figure 4 shows further steps in the use of the device 10. In this figure, the cross section extends into the area of ​​the conical portion 20, through the spacer 40 on the left side and through the area between the two spacers where no spacer is present on the right side. The implant 5 is moved further downward through roughly the center of the device. It can be seen that the wall of the opening 16 on the right side acts as a wiper 18, wiping away and retaining excess coating agent 8, thereby establishing a constant layer thickness of coating agent 8 on the implant 5. However, on the right side, the spacer 40 is in contact with the implant 5, thus preventing localized adhesion of the coating agent 8.

[0095] It has also been shown that the implant exhibits a diameter that increases towards the top. Due to the rubber-elastic properties of the conical portion 20, the opening 16 can be widened, and thus a certain layer thickness can be achieved in this case as well.

[0096] Furthermore, as shown in Figure 4, a piston 52 can be used to press the coating agent 8 downward. The diagram shows how the implant 5 passes through the opening 54 of the piston 52. The flexible cover 55 of the opening 54 bends into an arc.

[0097] A coated implant 5 is shown as an example in Figure 5. The implant includes strips of coating material 8 extending along its longitudinal axis, with these strips spaced apart by gaps 9 between them. The gaps correspond to the positions where the spacer contacts the implant 5.

[0098] Further embodiments of the device are shown in Figure 6 using an inverted exploded view. The lower section 15 shown above includes a slit-shaped opening 16, within which two rib-shaped spacers 40 are visible on each of the two long sides. The conical section is also slit-shaped or has an elongated cross-section. The device functions to coat a flat implant 5 using an osteosynthesis plate, as illustrated in Figure 7. In this case, the opening 54 of an optional piston 52 can also be designed to be slit-shaped. In principle, the basic shape of the opening is adapted to the outer cross-section of the implant and can be arbitrarily selected.

[0099] Figures 8 and 9 show cross-sections of a coated implant 5. The osseojunction plate is shown as an example against a flat implant 5. Typically, only the longer side is coated in cross-section. When spacers are placed on both sides as in Figure 6, the coating material 8 placed on both sides and the gap 9 between them create the pattern shown in Figure 8. However, when spacers are placed on only one side, the pattern shown in Figure 9 is created. Here, the coating material 8 is placed on only one side, with gaps 9 between them, while on the other side, the entire coating material is wiped off and retained by a wiper.

[0100] Figure 10 shows a cross-section of the rib-shaped spacer 40 in the viewing direction along the inner surface of the conical portion 20. Here, the spacer is shown as trapezoidal in shape as an example. The contact side 41 of the spacer 40 is in contact with the inner surface of the conical portion 20, and the free side 42 protrudes freely radially inward to contact the implant. The width B2 of the free side 42 is smaller than the width B1 of the contact side 41, which is measured parallel to it. [Explanation of symbols]

[0101] 5 Implants 7 Syringe 8 Coating agent 9 Gap 10 equipment 12 Reservoirs 15 Lower 16 Opening 17 Material 18 Wiper 20 Cone section 21 First side 22 Second side 25 Upper components 26 Lower components 31 First connection area 32 Second connection area 40 Spacers 41 Contact side 42 Free side 44 End B1 First width (BS) B2 Second width (FS) 50 cylinders 52 pistons 54 Opening 55 Cover A center axis α angle

Claims

1. A device (10) for coating an elongated implant (5), comprising a reservoir (12) for holding a coating agent (8), and a lower part (15) connected to or connectable to the reservoir (12) and having an opening (16), wherein the material (17) forming the opening (16) is rubber-elastic and functions as a wiper (18) for wiping off excess coating agent (8).

2. The apparatus (10) according to claim 1, wherein the lower part (15) includes a hollow conical portion (20), and the conical portion (20) is made of a rubber elastic material in particular.

3. The apparatus (10) according to claim 2, wherein the larger first side portion (21) of the conical portion (20) faces toward the reservoir (12), the smaller second side portion (22) of the conical portion (20) faces away from the reservoir (12), and the opening (16) is located toward the second side portion (22).

4. The apparatus (10) according to claim 2, wherein the reservoir (12) includes a first connection region (31), the lower part (15) includes a corresponding second connection region (32), and the first connection region (31) and the second connection region (32) are mechanically reversibly connectable to each other.

5. The apparatus (10) according to claim 1, wherein the opening (16) has a basic shape of a circle or a slit.

6. The apparatus (10) according to claim 1, wherein a spacer (40) is placed on the wiper (18) to ensure a distance between the wiper (18) and the elongated implant (5) to be coated.

7. The apparatus (10) according to claim 6, wherein the spacers (40) are arranged to be uniformly distributed in the circumferential direction.

8. The apparatus (10) according to claim 6, wherein the spacer (40) is configured to be rib-shaped and extends at an angle (α) of less than 30° with respect to the central axis (A) of the apparatus (10).

9. The apparatus (10) according to claim 8, wherein the rib-shaped spacer (40) includes a cross-section having a contact side (41) and a free side (42), and the first width (B1) of the spacer (40) on the contact side (41) is greater in at least some regions than the second width (B2) of the spacer (40) on the free side (42), which is measured parallel to the first width (B1).

10. The apparatus (10) according to claim 8, wherein the rib-shaped spacer (40) includes a triangular, trapezoidal, rectangular, or hemispherical cross-section.

11. The apparatus (10) according to claim 8, wherein one end (44) of the rib-shaped spacer (40) facing the reservoir (12) is designed to be rounded.

12. The apparatus (10) according to claim 1, wherein at least one side of the reservoir (12) facing away from the lower part (15) is designed as a cylinder (50), and the apparatus (10) further includes a piston (52) corresponding to the cylinder (50) for pressing the coating agent (8).

13. The apparatus (10) according to claim 6, wherein the lower part (15) includes a hollow conical portion (20), and the coating agent can sink into the hollow conical portion (20) by gravity during use of the apparatus (10).

14. A system comprising the device (10) according to claim 4 and an additional lower part (15) having an opening (16), wherein the material (17) forming the opening (16) is rubber-elastic and functions as a wiper (18), and the additional lower part (15) includes a second connection area (32) that corresponds to the first connection area (31) of the device (10) and can be mechanically and reversibly connected to the first connection area (31).

15. Use of the apparatus (10) according to claim 1 for coating an elongated implant (5).

16. A method for coating an elongated implant (5) using a device (10), comprising: providing a device (10) having a reservoir (12) that holds a coating agent (8); and moving the elongated implant (5) through the coating agent (8) through an opening (16) at the bottom (15) of the device (10), wherein excess coating agent (8) is wiped away from the implant (5) by a wiper (18) of the device (10).

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