Device and method for making spacers

Abstract

The invention relates to a device for producing a spacer, comprising a lower mold part (1) comprising a cavity (2), a mold wall (3) extending circumferentially away from the edge of the cavity (2) and open on the opposite side, an upper mold part (5) comprising a molding surface (6), wherein the upper mold part (5) can be inserted into an inner space (4) of the lower mold part (1) and can be moved in the direction of the cavity (2), thereby forming a hollow space bounded by the cavity (2), the molding surface (6) and the mold wall (3), in which a spacer can be molded, at least one container (7) for receiving excess bone cement paste, and at least one opening (8) in the molding surface (6) and / or the cavity (2), which opens into the at least one container (7) for receiving excess bone cement paste. The invention also relates to a method for producing a spacer using such a device.

Description

Technical Field

[0001] The present invention relates to a device for making a spacer by solidifying a bone cement (bone cement) paste in a casting mold, wherein the spacer is provided in the medical field for temporarily replacing a joint or a joint part including a joint articulation surface, in particular temporarily replacing a hip joint, a knee joint or a shoulder joint. In medical applications, the spacer is provided as a temporary placeholder for temporarily replacing a joint or a joint part including a joint articulation surface. The spacer is preferably suitable for and provided for temporarily replacing a hip joint, a knee joint or a shoulder joint. Therefore, the device is preferably provided for making a hip joint spacer, a knee joint spacer or a shoulder joint spacer. The present invention also relates to a method for making such a spacer using such a device.

[0002] Thus, the present invention provides, inter alia, a device for intraoperative production of hip, shoulder and knee spacers, which are used as temporary placeholders (spacers) in the transitional phase of secondary repair of infected hip, shoulder and knee endoprostheses. The device is suitable for producing spacers using low-viscosity and high-viscosity polymethylmethacrylate bone cement pastes. The present invention also provides a method for producing spacers using the device. Background Art

[0003] Intraarticular prostheses, such as hip, knee and shoulder endoprostheses, are widely implanted worldwide. Unfortunately, in a few cases, intraarticular prostheses are colonized by bacterial microorganisms, in particular Gram-positive as well as Gram-negative bacteria, and to a lesser extent by yeasts and fungi. These bacterial microorganisms - mainly typical skin microorganisms such as Staphylococcus aureus and Staphylococcus epidermidis - may enter the patient's body during surgical operations (OP). Bacterial microorganisms may also enter the intraarticular prosthesis via hematopoiesis. In the case of colonization of the intraarticular prosthesis with bacterial microorganisms, the surrounding bone and soft tissue are also infected and damaged by bacterial microorganisms.

[0004] The prior art mainly includes two methods for treating infected hip endoprostheses, namely, primary suppurative repair and secondary suppurative repair. In the case of primary repair, the infected endoprostheses are first removed in one OP, followed by the next lesion removal, and then the repair endoprostheses are implanted.

[0005] The hip spacer consists of a stem, a collar, a neck and a ball head, and replicates the shape and size of the hip prosthesis. Similarly, the shoulder spacer replicates the shape and size of the shoulder prosthesis. The knee spacer has a tibial component and a femoral component, and substantially replicates the shape and size of the knee prosthesis. The tibial component has a stem and a tibial plateau, wherein the tibial plateau forms a sliding or rolling surface of the knee joint, and the stem can be anchored to the tibia. The femoral component has a stem for anchoring in the femur and two condyles for rolling on the tibial plateau. The tibial component and the femoral component are anchored to their respective bones with bone cement, for example, in the case of the femoral component, anchored in the distal femur or in the femoral canal, and in the case of the tibial component, fixed with a stem in the proximal tibia or in the tibial canal.

[0006] The spacer is anchored with bone cement to the corresponding bone, i.e., in the case of a hip spacer, to the proximal femur or femoral canal. The spacer remains in the patient for several weeks until the inflammation subsides and clinical signs of inflammation disappear. The spacer is then removed in a second OP and a revision endoprosthesis is implanted after fresh debridement.

[0007] For the spacers, antibiotics have been added to the cement powder before the actual spacer production. Using this antimicrobial modified bone cement powder, a bone cement paste is then produced by adding and mixing a monomer liquid, and the spacer is molded from this bone cement paste, which is then cured by polymerization with the help of the monomer liquid added to the bone cement powder. Therefore, the bone cement paste basically encapsulates the antibiotic. Under the action of body fluids such as wound secretions, the antibiotic particles located in the area near the surface are released. The release of the active ingredient is maximum at the beginning and then gradually decreases over a few days.

[0008] US 2010 / 0042213 A1 discloses a hip prosthesis having a reservoir for a liquid inside the implant. A hip spacer having an indentation into which a substance for treating the bone can be introduced is known from WO 2017 / 178951 A1. Patent US 6,245,111 B1 proposes a hip prosthesis coated with an antibiotic. Patent US 5,681,289 discloses a device for dispensing a liquid active ingredient with the aid of a capsule within the device. EP 1 991 170 B1 and US 2011 / 0015754 A1 describe a hip spacer containing an active ingredient. US 2019 / 0290833 A1 discloses a flushable hip spacer that can be used to create a liquid circuit. WO 2016 / 205077 A1 and US Pat. No. 8,900,322 B2 further describe spacers with a flushing function.

[0009] In the secondary suppurative repair, in the first OP, the infected joint prosthesis is first removed, then debridement is performed, and thereafter the spacer is implanted. In the secondary suppurative replacement surgery of knee, hip and shoulder endoprostheses, the spacer is of great significance as a temporary placeholder in the transitional stage. During the intraoperative production of these spacers, medical personnel can add one or more antibiotics specifically for the microorganism to the polymethyl methacrylate (PMMA) bone cement according to the available antibacterial spectrum of the microorganism causing the infection. This bone cement is known, for example, in EP 1 985 317 B1. For the intraoperative production of spacers using polymethyl methacrylate bone cement, resin casting is conventional. This casting is known, for example, in patents EP 2 617 393 B1 and EP 3 075 357B1 and European patent applications EP 20 164 534 and EP20 164 541, which are not previously disclosed. A heatable casting mold is known from EP 2 818 138 B1.

[0010] On the one hand, the spacer can be made by the OP personnel during the OP itself from PMMA bone cement powder, antibiotics and monomer liquid, for example using a spacer mold, as described in patent DE 10 2015 104 704 B4 or EP 2 617 393 B1; on the other hand, it is also common to use hip spacers prefabricated industrially from bone cement. Resin casting molds for making one-piece hip spacers during surgery are described in US 6,361,731B1. These casting molds are transparent and have two separate filling openings. As a result, even high-viscosity bone cement paste balls can be introduced into the casting mold under less pressure due to the relatively short flow path of the bone cement paste ball. When using non-high-viscosity bone cement paste balls, once the filling of the casting mold is completed, the risk of the bone cement paste ball flowing back from the filling opening before curing begins arises.

[0011] As a further development, patents US 7,637,729 B2, US 7,789,646 B2, US 8,480,389 B2 and US 8,801,983 B2 propose multi-component castings for making modular hip spacers. These modular hip spacers include a spacer head and a separate rod. Therefore, a casting mold is required for the spacer head and a separate casting mold for the rod. The casting mold for the rod is integral and has threads at the filling opening for connecting the casting mold to a cement barrel containing a bone cement paste. This modular system must be assembled separately to the correct size and the parts must be connected together so that they can withstand the injection pressure of the bone cement paste, which is usually of high viscosity. Therefore, the cost of the multi-component casting is very high and it is also complicated to use.

[0012] US 7,789,646 B2 describes a casting mold, wherein after the bone cement paste mass is introduced into the casting mold, the filling opening of the casting mold can be closed with a plug. However, before this, the casting mold must be screwed off from the cement cartridge. Therefore, when using a low-viscosity cement paste mass, if the casting mold is fixed in an unfavorable manner, before the plug is screwed in, when the casting mold is separated from the cement cartridge, the cement paste mass may flow out. When using a high-viscosity bone cement paste mass, there is basically the same risk, because the pressure required for filling can cause elastic deformation of the casting mold, and when the casting mold returns to its shape, the bone cement paste mass inside can be pressed out from the opened filling opening.

[0013] US 2007 / 0222114 A1 describes a hip spacer mold. The spacer mold consists of multiple mold segments connected together. Due to the multiple segments, the spacer mold can be adapted to the patient's anatomical environment very accurately. The spacer mold segments are connected together by worm-driven hose clamps. PMMA bone cement paste (polymethyl methacrylate bone cement paste) is introduced through a channel in the spacer mold. After the PMMA bone cement paste is cured, the complex structure of the mold makes it very complicated to connect the spacer mold segments together and remove the hip spacer.

[0014] WO 2009 / 073781 A2 proposes a spacer mold for a hip spacer, which consists of two parts that can be moved relative to each other so that the length of the rod can be adjusted. Another casting mold is disclosed in EP 2 522 310 A1. The device consists of at least two parts, wherein an insertion part is provided in the first part and an insertion bracket is provided in the second part. The two parts can be inserted into each other and form a casting mold for making the rod of the hip spacer. EP2 787 928 A1 describes a complex casting mold. This makes it possible to make hip spacers with different ball heads. Connecting elements are used to fix multiple elements of the casting mold in place. Patent US 7,789,646 B2 describes a casting mold, wherein after the bone cement paste dough is introduced into the casting mold, the filling opening of the casting mold can be closed with a plug. However, before this, the casting mold must be unscrewed from the bone cement cartridge. Therefore, when using a non-high viscosity cement paste, if the casting mold is held in an unfavorable manner, the cement paste may flow out when the casting mold is separated from the cement cartridge before the plug is screwed in or inserted.

[0015] Documents EP 2 931 180 B1, US 2010 / 0102484 A1 and EP 2 532 323 B1 disclose various bone cement molds for making tibial components of knee spacers suitable for delivering antibiotics. However, assembling the multiple mold parts and fixing them together requires considerable effort. In addition, due to the multiple necessary components, the casting mold is complex, expensive and complicated to use. Patent EP 3 143 963 B1 discloses a three-part spacer mold, which includes a tibial spacer mold, a femoral spacer mold and a third mold for making a component for filling the intramedullary canal.

[0016] US 10,071,511 B2 discloses a plurality of castings for producing the tibial component of a knee spacer. Tibial components of different heights can be made using these castings. The castings comprise a lower part and an upper part which form a hollow space into which a polymethylmethacrylate bone cement paste mass can be injected through a port. The height of the tibial component to be cast is defined by a toothed latch mechanism which sets the distance between the lower and upper parts of the casting.

[0017] A similar concept is known from US 9,433,506 B2, which claims a mold for a knee spacer. The mold here contains a port, which after demoulding is present as a stem in the intramedullary space. With the aid of a cement cartridge, the mold is filled through the port. Summary of the invention

[0018] The object of the present invention is therefore to overcome the disadvantages of the prior art. In particular, the object of the present invention is to develop a low-cost device for making spacers by curing a bone cement paste in a casting mold with minimal effort, and to develop a method for making spacers by curing a bone cement paste in a casting mold that can be performed simply and inexpensively, by which medical personnel in an operating room can use bone cement paste, in particular polymethyl methacrylate bone cement, to make one-piece spacers, in particular hip and shoulder spacers.

[0019] The object of the present invention is therefore to develop a device which is inexpensive and simple to manufacture, with which the operating room staff can very directly manufacture articulated knee, hip and shoulder spacers as well as the tibial and femoral components of a knee spacer using polymethylmethacrylate bone cement. The structure of the hip and shoulder spacers is similar. They comprise a stem and a spacer head. For the purpose of mechanical stabilization, a metal core can be or has been provided in the hip and shoulder spacers. The knee spacer consists of the tibial and femoral components. It should be possible to manufacture the spacers not only using low-viscosity or non-high-viscosity, but also using high-viscosity (polymethylmethacrylate) bone cement pastes.

[0020] The device should preferably be configured to not require a bone cement system based on a dischargeable bone cement cartridge when making the spacer. The spacer can be made using a bone cement paste mass manually mixed in a mixing bowl with a mixing spatula. The device should preferably be able to be filled without using a bone cement cartridge to discharge the device. Any excess bone cement paste mass that overflows should be avoided as much as possible to contaminate medical staff and the operating room environment.

[0021] The object of the invention is achieved by a device for producing a spacer by curing a bone cement paste dough in a casting mold, wherein in the medical field the spacer is provided for temporary replacement of a joint or a joint part comprising a joint articulation surface, in particular for temporary replacement of a hip joint, a knee joint or a shoulder joint, the device comprising:

[0022] A casting mold lower part, wherein the casting mold lower part has a cavity for receiving a bone cement dough and for molding a first surface area of ​​the spacer from the bone cement dough;

[0023] a mold wall portion extending circumferentially from a circumferential edge of the mold cavity of the mold lower part away from the mold cavity and being open on a side opposite to the mold cavity, whereby the mold cavity can be approached (entered, operated) through an interior space defined by the mold wall portion;

[0024] an upper mold part, wherein the upper mold part has a molding surface for molding a second surface area of ​​the spacer from a bone cement paste dough, wherein the upper mold part can be inserted into the inner space through an open side of the mold wall opposite to the mold cavity and can be displaced in the direction of the mold cavity (towards the mold cavity) to form a hollow space, which is delimited by the mold cavity of the lower mold part, the molding surface of the upper mold part and the mold wall, and the spacer can be molded in this hollow space;

[0025] at least one container for receiving excess (excess) bone cement paste; and

[0026] at least one opening in the molding surface of the upper mold part and / or in the mold cavity of the lower mold part, wherein the at least one opening opens into the at least one container for receiving excess bone cement paste, wherein

[0027] The device has one or two covers, by means of which the upper part of the mold is or can be closed to the outside on the side opposite to the molding surface of the upper part of the mold, thereby forming an upper container closed to the outside between the upper part of the mold and the cover to serve as one of the at least one container for receiving the bone cement paste ball, and / or by means of the cover, the lower part of the mold is or can be closed to the outside on the side opposite to the mold cavity of the lower part of the mold, thereby forming a lower container closed to the outside between the lower part of the mold and the cover to serve as one of the at least one container for receiving the bone cement paste ball, and

[0028] The cover or one of the cover(s) is or can be placed above or inside the upper part of the mold, or above or inside the inner wall of the upper part of the mold, so as to close the side opposite to the molding surface of the upper part of the mold to the outside and form a closed container for receiving excess bone cement paste therein, and / or the cover or one of the cover(s) is or can be placed above or inside the lower part of the mold, so as to close the side opposite to the mold cavity of the lower part of the mold to the outside and form a closed container for receiving excess bone cement paste therein.

[0029] It is preferably conceivable that the casting mold wall has a height of at least 10 mm.

[0030] The at least one opening is preferably only arranged in the molding surface of the casting mold upper part. Like this, low-viscosity bone cement also can be introduced into the mold cavity, and can not flow out through the at least one opening in the mold cavity.

[0031] The molding surface of the upper part of the casting mold can also be formed as a mold cavity.

[0032] The casting mold wall preferably encloses an interior space which adjoins the volume bounded by the cavity of the casting mold lower part.

[0033] The container may be open, but is preferably or can be sealed impermeably to the bone cement mass to prevent the bone cement mass from contaminating the surrounding environment.

[0034] When making hip and shoulder spacers, the mold is preferably divided into a lower mold part and an upper mold part in the center of the spacer to be made. This means that half of the spacer is formed by the cavity of the lower mold part and the other half is formed by the molding surface of the upper mold part.

[0035] In the case of the tibial and femoral components of the knee spacer, it is advantageous and preferred that the cavity of the lower mold part reproduces the shape of the sliding surface and the molding surface of the upper mold part reproduces the corresponding back side of the knee spacer component. In this case, the dividing line is advantageously located at the upper edge of the back side of the knee spacer component.

[0036] The device is preferably suitable for low-viscosity bone cement dough or for cooling medium-high-viscosity bone cement dough.

[0037] The at least one container for receiving the bone cement dough is preferably sealed impermeably with respect to the outside with respect to the bone cement dough.

[0038] The cavity is preferably formed in the manner of a hemispherical shell.

[0039] In the device according to the invention, it is conceivable that mutually opposing parts of the mold wall are oriented parallel to each other, or that the mold wall is slightly tapered in the direction of the cavity, or that the mold wall has an upright or inclined, roughly cylindrical shape, the base area of ​​which is delimited by the circumferential edge of the cavity.

[0040] In this way, the mold upper part can be moved linearly (straightly) in the mold wall and, in addition to at least one opening, can also seal the hollow space at the top at the same time. Therefore, the bone cement paste mass in the mold can be pressed into a desired shape.

[0041] The casting mold is slightly conical in the direction of the cavity, which means that the acute angle of the cone or the angle at which the walls are inclined relative to one another does not exceed 15°, preferably does not exceed 4°, particularly preferably does not exceed 1°.

[0042] The generally cylindrical shape is obtained by a linear displacement of the base area, which in this case is bounded by the peripheral edge of the cavity. In a straight cylinder, the displacement is carried out perpendicularly to the base area, while in an inclined cylinder it is carried out at an angle other than 90°.

[0043] Furthermore, it is also conceivable that the inner wall extends circumferentially from the circumferential edge of the molding surface of the upper part of the mold in a direction away from the cavity of the lower part of the mold, wherein the inner wall preferably at least partially (in certain locations) defines the at least one container and / or mutually opposing parts of the inner wall are oriented parallel to each other, or the inner wall has a vertical or inclined, roughly cylindrical shape, the base area of ​​which is defined by the circumferential edge of the molding surface of the upper part of the mold.

[0044] The inner wall can provide a flat seal to the mold wall.At the same time, the mold upper part is stably guided in the mold wall.

[0045] The inner wall is called the inner wall because it is arranged on the inner side relative to the mold wall. In this case, the inner wall should not be considered to refer to the inward side of the wall under any circumstances, but to the physical wall with volume.

[0046] The inner wall can preferably be formed in one piece with the upper part of the casting mold and particularly preferably is part of the upper part of the casting mold.

[0047] It is also conceivable that the inner wall has a height of at least 10 mm.

[0048] Furthermore, it is also conceivable that the outer circumferential length of the inner wall is exactly the same as or slightly smaller than the inner circumferential length of the wall of the casting mold.

[0049] It is also conceivable that the inner wall and the mold wall abut flush against each other when the mold upper part is pushed into the mold wall and / or that the inner wall forms a seal against the mold wall for the bone cement paste ball when the mold upper part is pushed into the mold wall.

[0050] In this way, a hollow space is formed inside the assembled mold parts of the device, which is sealed to the outside and serves to form the spacer. In addition, this prevents the upper mold part from tilting relative to the lower mold part. Thus, unintentional tilting of the surfaces of the spacers relative to one another, for example an unintentional tilting of the tibial plateau relative to a remaining tibial knee spacer, can be prevented. In addition, the punch-type upper mold part is stabilized in this way, so that the upper mold part can also be produced from a thin plastic film.

[0051] It is envisaged that the device has one or two covers, through which the upper part of the mold is or can be closed to the outside on the side opposite to the molding surface of the upper part of the mold, thereby forming an upper container closed to the outside between the upper part of the mold and the cover to serve as the at least one container for receiving the bone cement paste ball, and / or through which the lower part of the mold is or can be closed to the outside on the side opposite to the mold cavity of the lower part of the mold, thereby forming a lower container closed to the outside between the lower part of the mold and the cover to serve as the at least one container for receiving the bone cement paste ball.

[0052] It is envisaged that the cover or one of the cover members is or can be placed above or inside the upper part of the mold, or above or inside the inner wall of the upper part of the mold, so as to close the side opposite to the molding surface of the upper part of the mold to the outside and form a closed container for receiving excess bone cement paste there, and / or the cover or one of the cover members is or can be placed above or inside the lower part of the mold, so as to close the side opposite to the mold cavity of the lower part of the mold to the outside and form a closed container for receiving excess bone cement paste.

[0053] The cover can mechanically stabilize the mold upper part and / or the mold lower part, in particular if the mold upper part and the mold lower part are made of or have a plastic film. This further prevents the bone cement paste mass that overflows from the at least one opening from contaminating or soiling the surroundings. In this way, the user can avoid any possible harmful contact with the bone cement paste mass and prevent contamination of the spacer through the at least one opening, or at least make it more difficult to contaminate.

[0054] A further development of the invention can provide that the cover element (or the cover elements) have at least one ventilation opening and / or that the cover element together with the casting mould upper part is or can be sealed gas-permeably.

[0055] In this way, when the bone cement paste mass flows through the at least one opening in the container, air can escape from the upper or lower container defined by the cover or the container defined by the cover. Any possible gas back pressure can thus be prevented from occurring.

[0056] Furthermore, it is also conceivable that the sum of the volume of the cavity of the lower mold part and the volume bounded by the mold wall is greater than the volume of the spacer element to be produced.

[0057] This ensures that the cement bolus can be introduced in excess to avoid air inclusions in the spacer.

[0058] It is also conceivable that the mold wall and the mold lower part are formed as one piece, wherein the mold wall is preferably part of the mold lower part.

[0059] In this way, the device has lower cost and is simpler to manufacture.

[0060] It is also conceivable that the device has a mixing system for mixing bone cement dough, cement powder and monomer liquid, wherein the cement powder and the monomer liquid are stored separately from one another, wherein the bone cement dough can be mixed from the cement powder and the monomer liquid by means of the mixing system.

[0061] It is also conceivable that the mixing system preferably comprises a mixing cup, which preferably has a mouth for introducing the bone cement paste dough from the mixing cup into the mold cavity and the inner space defined by the mold wall. It is also conceivable that the mixing system is a bone cement cartridge for storing and mixing cement powder and monomer liquid and for conveying the mixed bone cement paste dough from the bone cement cartridge, wherein the bone cement cartridge preferably contains the cement powder and the monomer liquid in areas separated from each other in a liquid-tight manner.

[0062] The hybrid system further completes the device and can be used directly to make spacers.

[0063] In principle, the device can also comprise only cement powder and monomer liquid, preferably a closed first container containing cement powder and a closed second container containing monomer liquid.

[0064] It is further conceivable that the lower mold part and the upper mold part, preferably also the mold wall and the cover part if present, consist of or essentially consist of plastic film, or that the lower mold part and the upper mold part, preferably also the mold wall and the cover part if present, each consist of two or more plastic films that are connected together, in particular preferably welded or adhesively joined together.

[0065] In this way, the structure is particularly cheap, but surprisingly still strong enough to mold the bone cement spacer therein. In addition, after use, the device can be processed cheaply and cleanly by incineration.

[0066] The mold lower part and the mold upper part, as well as the mold wall and / or the cover if present, essentially consist of a plastic film or two or more plastic films connected together, which means that at least 50% of the volume or weight of the mold lower part and the mold upper part and the optional mold wall and / or the cover consists of a plastic film or two or more plastic films connected together.

[0067] The casting mold lower part and the casting mold upper part, preferably also the casting mold wall and, if present, the cover, are preferably produced from thermoformed plastic films.

[0068] For the purposes of this patent application, the film preferably has a thickness of at most 2 mm, preferably at most 1 mm.

[0069] The film or films connected together should preferably be self-supporting, ie not in the form of a coating.

[0070] It is also conceivable that the mold lower part, the mold upper part and the mold wall and the cover if present are essentially or completely composed of plastic material, preferably made of polyolefin, polyethylene (PE) or polypropylene (PP), particularly preferably made of PETG film and / or polyamide film and / or PE film.

[0071] In this way, the structure is also particularly cheap. In addition, after use, the device can be disposed of cheaply and hygienically by incineration.

[0072] It is conceivable that the at least one opening has a minimum cross-sectional length of at most 2.5 mm, preferably a minimum cross-sectional length of at most 2 mm, particularly preferably a minimum cross-sectional length of at most 1.5 mm, very particularly preferably a minimum cross-sectional length of at most 1 mm.

[0073] The maximum cross-sectional length ensures that the cement mass solidifies in the at least one opening, i.e. the gate formed in the at least one opening, can still be sheared or broken off without tools to demould the spacer. Once the cement mass solidifies, the small diameter of the at least one opening means that the cement gate through the opening, i.e. the gate connecting the solidified spacer and the excess cement mass on the side opposite to the molding surface of the upper part of the casting mold, can be easily separated by shearing or breaking off.

[0074] The minimum cross-sectional length of an opening refers to the narrowest dimension of the cross-sectional area suitable for free flow (perpendicular to the flow direction). In the case of a slit-shaped opening, for example, this is the width of the slit, not the length.

[0075] Furthermore, it is also conceivable that the at least one opening has a minimum cross-sectional length of at least 0.2 mm, preferably at least 0.5 mm, particularly preferably at least 1 mm.

[0076] The minimum cross-sectional length ensures that even if the viscosity of the cement dough is very high, the cement dough can be pressed through the at least one opening without excessive mechanical pressure. Excess cement dough can flow through the opening designed in this way without any excessive pressure being applied to the cement dough, which pressure either cannot be applied manually or could damage or destroy the casting mold.

[0077] The at least one opening is preferably not elongated, and particularly preferably its length is at most twice its width.

[0078] A further development can be envisaged in which a limit stop is provided at the end of the mold wall opposite to the cavity of the lower part of the mold, for limiting the movement of the upper part of the mold in the direction of the cavity within the mold wall, wherein the contact surface is preferably provided as a limit stop at the end of the mold wall opposite to the cavity of the lower part of the mold, and the contact surface particularly preferably extends at a right angle from the mold wall.

[0079] In this way, the upper mold part can be pushed into the mold wall until the limit stop is reached in order to mold the spacer from the bone cement dough.

[0080] It is also conceivable that the device has a metal core which will be or has been arranged in the mold cavity, wherein the device preferably has a plurality of spacer parts which keep the metal core spaced apart from the inner side of the mold cavity and the inner side of the mold wall in the mold cavity, wherein the spacer parts are particularly preferably composed of cured bone cement, in particular polymethyl methacrylate.

[0081] In this way, a mechanically stable reinforcement in the form of a metal core can be provided in the spacer to be produced.

[0082] In a device with a metal core, it is conceivable that the metal core has a hole (cavity) for receiving a pin-shaped spacer part, wherein the hole is preferably not arranged in the cavity area for molding the sliding surface of the spacer, and it is particularly preferred that the hole is arranged in the cavity area for molding the spacer rod.

[0083] When making hip and shoulder spacers, it is advantageous to provide a metal core in the lower part of the mold, which is spaced from the wall of the lower part of the mold by a spacer element. Polymethyl methacrylate pins are particularly suitable as spacer elements. These pins are bonded to the bone cement dough and can be trimmed to the contour of the spacer after curing.

[0084] Furthermore, it is also conceivable that the mold lower part or the mold upper part and the mold wall, or the mold lower part, the mold wall and the mold upper part are transparent or translucent.

[0085] In this way, during the process of filling the cavity and forming the spacer, it is possible to visually monitor whether and how the spacer mold is filled with the bone cement paste and how the bone cement paste is solidified therein. Therefore, it is possible to visually monitor whether the spacer has obtained the desired shape.

[0086] It is further conceivable that the at least one opening is arranged in a region which is the highest point of the hollow space in the normal configuration of the casting mould.

[0087] In this way, the formation of trapped air in the hollow space which cannot escape from the hollow space can be prevented.

[0088] It is also conceivable that the outer edge of the molding surface of the mold upper part bears against the mold wall on the inside (of the mold wall) and when the mold upper part is pushed in, the edge slides on the inside on the mold wall, wherein the edge preferably has a scraping edge or a scraping lip.

[0089] This ensures that the bone cement dough can be used in the inner space of the casting mould when the casting mould upper part is pushed in to gather and compress the bone cement dough.

[0090] Furthermore, it is also conceivable that the device has a support, wherein the lower part of the mold can be inserted into the support, and the support and the lower part of the mold therein are suitable for being placed on a flat support, wherein the support preferably consists essentially or completely of a plastic film or of two or more plastic films connected together, particularly preferably welded or adhesively joined together.

[0091] The advantage of doing this is that, during the molding process of the spacer, the device can be placed on a flat support such as a table. At the same time, the bracket can be used for stabilizing the casting mold, in particular the lower part of the casting mold.

[0092] The stent may consist essentially or entirely of PE, PP or a polyolefin.

[0093] A stent substantially consisting of a plastic film or consisting of two or more plastic films connected together means that at least 50% of the volume or weight of the stent consists of a plastic film or two or more plastic films connected together.

[0094] The object of the present invention is also achieved by a method for making a spacer, which is used to temporarily replace a joint or a joint part, especially a hip joint, a knee joint or a shoulder joint, and the joint part includes the articulation surface of the joint, wherein the method is carried out using the above-mentioned device and comprises the following steps arranged in time.

[0095] A) introducing a flowable bone cement paste mass into the mold cavity and the inner space defined by the wall portion of the casting mold, wherein the volume of the introduced flowable bone cement paste mass is greater than the volume required by the spacer;

[0096] B) inserting the upper mold part into the mold wall, wherein the molding surface points in the direction of the mold cavity;

[0097] C) pushing the upper part of the mold into the mold wall in the direction of the mold cavity;

[0098] D) when the upper part of the casting mold is continuously pushed in, excess bone cement paste overflows through the at least one opening, wherein the excess bone cement paste flows into at least one container for receiving the excess bone cement paste;

[0099] E) When the limit stop is reached or the desired height of the spacer is reached, the pushing is ended;

[0100] F) allowing the bone cement paste mass to solidify in the hollow space formed by the mold cavity, the molding surface of the upper part of the mold and the wall of the mold; and

[0101] G) removing the spacer molded and cured in this way from the hollow space, wherein the gate of the cured bone cement dough formed in the at least one opening is separated;

[0102] The method is preferably performed using a PMMA bone cement paste.

[0103] The method preferably uses a low viscosity bone cement paste or a cooled medium to high viscosity bone cement paste.

[0104] It is conceivable that in step D), the excess bone cement paste flows into a lower container closed by a cover for receiving excess bone cement paste on the lower part of the casting mold and is sealed in the lower container, and / or flows into an upper container closed by a cover for receiving excess bone cement paste on the upper part of the casting mold and is sealed in the upper container, wherein, when the cured spacer is demolded after step F) or in step G), the cured excess bone cement paste remains in the lower container and / or the upper container.

[0105] This prevents the cement clump from flowing out and contaminating the surrounding environment.

[0106] Furthermore, it is also conceivable that before step A), a bone cement dough is mixed from a monomer liquid and cement powder, in particular until a homogeneous bone cement dough is obtained, and that a metal core is preferably arranged in step A), wherein the metal core is preferably spaced apart from the inner walls of the cavity and the mold wall by means of pin-shaped spacer parts.

[0107] This completes the method.

[0108] It is also conceivable that in step C), air is discharged from the hollow space defined by the cavity of the mold lower part, the molding surface of the mold upper part and the mold wall through the at least one opening.

[0109] This prevents trapped air from forming unwanted defects in the spacer.

[0110] Finally, it is conceivable that, after step F) and before step G), the upper part of the casting mold is removed from the open end of the casting mold wall.

[0111] This simplifies demoulding of the spacer.

[0112] The present invention is based on a surprising realization that by pushing two parts of a casting mold into each other, the casting mold contains excess bone cement paste mass for making a spacer, and through a highly simplified and inexpensive casting mold, the excess bone cement paste mass can overflow from the casting mold through at least one suitable opening in the molding surface. The overflowing bone cement paste mass is preferably captured and enclosed in a closed area on the casting mold. The at least one opening is preferably arranged at a point (position) of the casting mold, which is located at the top during the use of the casting mold so that the residual air can escape through the at least one opening, thereby avoiding defects in the spacer. When using the device, at least one container for receiving excess bone cement paste mass can prevent the user and the surrounding environment from being polluted by the bone cement paste mass overflowing from the casting mold. At the same time, the use of the device is also simplified.

[0113] An exemplary device according to the present invention may consist of the following parts:

[0114] a) a lower mold part comprising at its top at least one cavity for molding the spacer,

[0115] b) a mold wall arranged vertically and upwardly and adjacent to the mold cavity, wherein mutually opposing wall portions of the mold wall are parallel to one another, wherein the circumferential mold wall encloses the interior space,

[0116] c) a mold upper part comprising at its bottom at least one surface for forming the spacer,

[0117] d) an inner wall arranged vertically and upwardly and adjacent to the forming surface, wherein mutually opposing wall portions of the inner wall are parallel to each other,

[0118] e) a cover which is inserted into the upper part of the casting mold and closes the space formed by the top and the inner wall of the upper part of the casting mold, said space serving as a container for receiving excess bone cement paste,

[0119] f) at least one opening in the wall of the upper mold part, said opening connecting the molding surface of the upper mold part with the space formed by the top and the inner wall of the upper mold part,

[0120] g) wherein the upper mold part is arranged to slide vertically on the lower mold part,

[0121] h) wherein the sum of the volumes of the cavity and the interior space delimited by the circumferential mold wall is greater than the volume of the spacer to be produced, and

[0122] i) wherein, once the mould cavity and the interior space delimited by the circumferential mould wall have been filled with the bone cement dough and the upper mould part is subsequently pushed in the direction of the mould cavity, excess bone cement dough overflows through at least one opening in a container for receiving the excess bone cement dough and remains in the container, which is closed at the top by a cover.

[0123] The device according to the present invention is used in such a way that first a mass of bone cement is introduced into the cavity of the lower part of the mold and the inner space defined by the mold wall. The volume of the mass of bone cement should be larger than the volume of the spacer to be made. Subsequently, the upper part of the mold is inserted into the lower part of the mold. The outer side of the inner wall of the upper part of the mold abuts against the mold wall of the lower part of the mold from the inside. Then pressure is applied to the upper part of the mold or the cover of the upper part of the mold to move the upper part of the mold downward in the direction of the cavity of the lower part of the mold. The air above the mass of bone cement in the interior defined by the mold wall and the molding surface of the upper part of the mold escapes through at least one opening in the space formed by the top and the inner wall of the upper part of the mold, i.e., enters a container for receiving excess mass of bone cement. The mass of bone cement contacts the molding surface of the upper part of the mold and then covers the surface. As it continues to move, the bone cement paste mass flows along the contour of the cavity wall (inside of the cavity) of the mold bottom part, until the bone cement paste mass arrives at least one opening. The cavity of the mold bottom part and the molding surface of the mold top part are therefore filled with the bone cement paste mass. The spacer is thus molded. Then, the bone cement paste mass solidifies by free radical polymerization. Once solidification is completed, the mold top part is removed from the mold bottom part. The molded spacer is usually still adhered to the mold top part, because it is connected to the mold top part by the undercut in the region of at least one opening. Then the mold top part is separated from the spacer. In the process, the bone cement gate passing at least one opening is sheared off, and stays in the container for receiving excess bone cement paste mass.

[0124] According to the present invention, an exemplary method for making a spacer using the device according to the present invention may comprise the following consecutive steps:

[0125] a) mixing cement powder with monomer liquid and mixing the cement components uniformly until a uniform bone cement paste mass is obtained,

[0126] b) introducing a mass of bone cement into the cavity of the lower part of the casting mold and into the interior space defined by the casting mold wall,

[0127] c) inserting the upper mold part into the inner space of the lower mold part which is defined by the mold wall,

[0128] d) pressing the upper mold part downwards in the direction of the cavity of the lower mold part,

[0129] e) allowing air to escape from the interior space of the casting mold between the bone cement dough and the molding surface of the casting mold upper part through the at least one opening and into the space formed by the top and the inner wall of the casting mold upper part,

[0130] f) allowing excess bone cement paste to be discharged from the inner space of the casting mold through the at least one opening and into the space formed by the top and inner wall of the upper part of the casting mold as a container for receiving the excess bone cement paste,

[0131] g) solidifying the bone cement paste,

[0132] h) remove the upper part of the mold, and

[0133] i) Demolding the solidified spacer, wherein the solidified excess bone cement mass remains in the space formed by the top and the inner wall of the upper part of the casting mold as a container for receiving the excess bone cement mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0134] The exemplary embodiments of the present invention are further explained below with reference to thirty-five schematic drawings, but the present invention is not limited thereby. In the drawings:

[0135] Figure 1 shows a schematic perspective exterior view of a first exemplary embodiment of the invention as an apparatus for producing a hip spacer, with the individual parts depicted separately;

[0136] Figure 2 A schematic plan view of an opened upper part of a casting mold is shown;

[0137] Figure 3 The following diagram shows the process of placing the metal core in the lower part of the mold before Figure 1 and Figure 2 A schematic perspective exterior view of a first exemplary embodiment of ;

[0138] Figure 4 shows a schematic perspective exterior view of the casting mold of the first exemplary embodiment during the introduction of a bone cement dough;

[0139] Figure 5 shows a schematic perspective exterior view of a first exemplary embodiment before the upper casting mold part is inserted into the lower casting mold part;

[0140] Figure 6 shows a schematic plan view of a closed casting mold of a first exemplary embodiment with section B indicated;

[0141] Figure 7 The first exemplary embodiment is shown in a closed state. Figure 6 A schematic cross-sectional view of section B;

[0142] Figure 8 shows a schematic perspective oblique cross-sectional view of a casting mold filled with a bone cement dough of a first exemplary embodiment in a closed state;

[0143] Fig. 9 Shown without cover Figure 8 A schematic perspective view of a device;

[0144] Fig.10 Shows the use of Figures 1 to 9 A schematic perspective view of a spacer produced by the apparatus of the first exemplary embodiment;

[0145] Fig.11 Shows the separation of the spacer parts according to Fig.10 A schematic cross-sectional view of a spacer;

[0146] Fig.12 shows a schematic perspective view of the various components of a second exemplary embodiment of the present invention as an apparatus for making a shoulder joint spacer;

[0147] Fig.13 The following diagram shows the process of placing the metal core in the lower part of the mold before Fig.12 A schematic perspective exterior view of a second exemplary embodiment of ;

[0148] Fig.14 shows a schematic perspective exterior view of a casting mold of a second exemplary embodiment during the introduction of a bone cement dough;

[0149] Fig.15 shows a schematic perspective exterior view of a second exemplary embodiment before the casting mold upper part is inserted into the casting mold lower part;

[0150] Fig.16 shows a schematic perspective view of a closed casting mold of a second exemplary embodiment;

[0151] Fig.17 shows a schematic perspective view of a first exemplary embodiment during removal of a cured spacer;

[0152] Fig.18 Shows the use of Figures 12 to 17 A schematic perspective side view of a spacer produced by the apparatus of the second exemplary embodiment;

[0153] Fig.19 shows a schematic plan view of a closed casting mold of a second exemplary embodiment with sections A and B indicated;

[0154] Fig. 20 The second exemplary embodiment in the closed state is shown according to Fig.19 A schematic cross-sectional view of section B;

[0155] Fig.21 The second exemplary embodiment in the closed state is shown according to Fig.19 A schematic cross-sectional view of section A;

[0156] Fig. 22 shows a schematic perspective cross-sectional view of a casting mold filled with a bone cement dough according to a second exemplary embodiment in a closed state;

[0157] Fig.23 A schematic perspective view of the individual components of a third exemplary embodiment of the invention as a two-component apparatus for making an articulated spacer for a knee joint is shown;

[0158] Fig.24 The lower part of the mold is shown in FIG. Fig.23 A schematic perspective exterior view of a third exemplary embodiment of ;

[0159] Fig.25 shows a schematic perspective exterior view of a casting mold of a third exemplary embodiment during the introduction of a bone cement paste dough;

[0160] Fig.26 shows a schematic perspective exterior view of a third exemplary embodiment before the casting mold upper part is inserted into the casting mold lower part;

[0161] Fig. 27 shows a schematic perspective exterior view of a third exemplary embodiment during the insertion of the casting mold upper part into the casting mold lower part;

[0162] Fig.28 shows a schematic perspective view of a closed casting mold of a third exemplary embodiment;

[0163] Fig.29A schematic perspective sectional view of a casting mold filled with a bone cement dough according to a third exemplary embodiment is shown in a closed state;

[0164] Fig.30 shows a schematic perspective exterior view of a third exemplary embodiment when the casting mold upper part is removed from the casting mold lower part;

[0165] Fig.31 shows a schematic perspective view of the individual components of a third exemplary embodiment with two spacers for a knee joint;

[0166] Fig.32 shows a schematic perspective view of a third exemplary embodiment with a closed casting mold and a support for the casting mold;

[0167] Fig.33 shows a schematic cross-sectional view of a casting mold of a third exemplary embodiment in a closed state;

[0168] Fig.34 A schematic perspective view showing two parts of a spacer produced using an apparatus according to a third exemplary embodiment; and

[0169] Fig.35 A schematic plan view of a casting mold without a cover member of a third exemplary embodiment is shown. DETAILED DESCRIPTION

[0170] Figures 1 to 9 Various views showing a first exemplary embodiment of a device for making a hip joint spacer according to the invention and components of said device. Figures 1 to 11 The process of a first exemplary embodiment of a method according to the present invention is shown, the method being carried out using a device according to the first exemplary embodiment.

[0171] A first device according to the invention is suitable and provided for making a spacer 42 for a hip joint (see Fig.10 and 11 The device comprises a multi-part casting mold. The casting mold comprises a lower casting mold part 1 and an upper casting mold part 5. A cavity 2 is provided in the lower casting mold part 1 for receiving a bone cement paste mass 36 (see Figure 4 , 5and 8) and are used to form a partial surface of the spacer 42 to be made. The cavity 2 can form the shape of half of the spacer 42. The mold wall 3 can be arranged at the edge of the cavity 2, and the mold wall 3 extends the hollow space formed by the cavity 2 and the inner space 4. The mold wall 3 can surround the edge of the cavity 2 circumferentially (on the periphery) for this purpose. The walls of the mold wall 3 can be oriented parallel to each other so that the mold wall 3 has a roughly cylindrical geometry, wherein the bottom area of ​​the roughly cylindrical shape is limited by the area that defines the edge of the cavity 2. The inner space 4 for introducing the bone cement paste mass 36 is arranged in the wall of the mold wall 3, and the inner space is connected to the cavity 2 and is preferably also aligned with the cavity 2.

[0172] The upper mold part 5 can preferably be inserted or pushed into the lower mold part 1. The upper mold part 5 has a molding surface 6 at its bottom, by which a further part of the surface of the spacer 42 to be produced is moldable, preferably the remaining part of the surface of the spacer 42 to be produced is moldable. Together with the cavity 2, the molding surface 6 can define the entire surface of the spacer 42 or at least 90% of the entire surface of the spacer 42. The molding surface 6 can form an indentation in the upper mold part 5. It is also possible that a part of the mold wall 3 forms a part of the surface of the spacer 42, or that one or more inserts (not shown) that mold a part of the surface of the spacer 42 are inserted into the cavity 2 and / or placed on the molding surface 6.

[0173] Container 7 (see Figure 8 and 9 ) can be arranged on the side of the upper part 5 of the mold opposite to the molding surface 6. There can be openings 8 in the molding surface 6, which provide a connection channel for the excess bone cement paste mass 38 from one side of the molding surface 6 to the container 7. The openings 8 are preferably arranged at points of the molding surface 6, which are the highest molding points of the mold in a suitable configuration of the device. In this way, the gas trapped in the mold can escape through the openings 8, thereby avoiding the residual air in the spacer 42 to be produced.

[0174] The container 7 can be or has been closed by the cover 9 so that the cement mass 36 is impermeable to the outside. The inner wall 11 that delimits the container 7 can start from the back of the molding surface 6 and extend from the back. The inner wall 11 can be aligned with the mold wall 3 on the outside in a perfect fit (form fit, perfect fit). In this way, the mold upper part 5 can be inserted into the mold wall 3 of the mold lower part 1 in a perfect fit, and the bone cement mass 36 is accordingly gathered from the inside of the mold wall 3 and pressed into the mold cavity 2 and the molding surface 6. It is also sufficient to achieve this purpose if the mold wall 3 tapers in the direction of the mold cavity 2, wherein the taper angle must be an acute angle.

[0175] The container 7 can be connected to the surrounding environment in a gas-permeable manner. For this purpose, it is conceivable that the cover 9 is not closed with a compression seal and / or that a small ventilation opening (not visible in the figure) is provided on the cover and / or the inner wall 11.

[0176] A metal core 10 may be provided as a reinforcement for the spacer 42. To this end, the metal core 10 may be spaced apart from the inside of the cavity 2 and the mold wall 3 by means of a pin-shaped spacer element 12 of solidified PMMA, so that the bone cement paste mass 36 may flow completely around the metal core 10 between the metal core 10 and the inside of the cavity 2 and the molding surface 6. In order to position the spacer element 12, a hole 14 may be provided in the metal core 10 for receiving one end of the pin-shaped spacer element 12. Similarly, a matching indentation may also be provided on the inside of the cavity 2 for receiving the other end of the pin-shaped spacer element 12.

[0177] A support 16 may be provided, into which the mould lower part 1 may be placed or inserted, to position the mould correctly, with the mould lower part 1 below and the mould wall 3 vertically above. The support 16 may be provided to be placed on a flat surface, such as a table.

[0178] The mold bottom part 1, the mold top part 5, the cover 9 and the support 16 can be made inexpensively from a plastic film or a plurality of plastic films connected together, in particular by injection molding or thermoforming. In the assembled state, the parts of the device made of plastic film are mechanically stabilized against each other. The plastic film preferably comprises a polyolefin, polyethylene (PET) or ethylene glycol-modified PET (PETG). When a plurality of films are used, they can be laminated together with an adhesive or by high temperature.

[0179] Internal grooves 18 and external gates 19 may be provided in the mold wall 3, extending downward from a limit stop 20 on the side of the mold wall 3 opposite to the cavity 2 to the edge of the cavity 2. The gate 19 may include a space for forming the grooves 18. The ends of the pin-shaped spacing members 12 inserted into and protruding from the holes 14 of the metal core 10 may be guided to the cavity 2 along these grooves 18.

[0180] A groove 21 matching the gate 19 can be provided inside the support 16. Therefore, the mold lower part 1 can be pushed into the support 16 in a guided manner, and the mold lower part 1 is not so easy to separate from the support 16, nor is it so easy to move relative to the support 16.

[0181] To fix the spacing elements 12 and thus the metal core 10 in place, matching recesses 23 may be provided at the edge of the molding surface 6 of the mold upper part 5. The recesses 23 may be provided at the edge of the molding surface 6 so that when the mold upper part 5 is pushed into the mold wall 3 of the mold lower part 1, they can move along the grooves 18 of the mold wall 3. The ends of the spacing elements 12 extending from the metal core 10 are accordingly clamped in the mold and located between the mold upper part 5 and the mold lower part 1.

[0182] The limit stop 20 can be provided as a circumferential strip-shaped edge which projects vertically from the mold wall 3 on the side of the mold wall 3 facing away from the mold cavity 2. The limit stop 20 can limit the extent to which the mold upper part 5 can be pushed into the mold lower part 1. For this purpose, the mold upper part 5 can have a counter-stop 22 in the form of a circumferential edge which projects vertically from the inner wall 11 and is arranged on the side of the inner wall 11 opposite to the molding surface 6. When the mold upper part 5 is completely pushed into the mold lower part 1, the counter-stop 22 abuts against the limit stop 20. In the same way, a cover edge 24 can be provided on the cover 9, which can be placed on the side of the counter-stop 22 opposite to the limit stop 20. Since the limit stop 20, the counter-stop 22 and the cover edge 24 project from the adjacent parts at a certain angle, the shape of the mold lower part 1, the mold upper part 5 and the cover 9 is mechanically stabilized in the assembled state. This is particularly helpful if the parts are produced from a plastic film or multiple plastic films by thermoforming.

[0183] The apparatus may also include a mixing cup 26 having a spout 28 for pouring the bone cement paste 36 from the mixing cup 26 (see Figure 3 ), as well as a film bag 30 filled with cement powder, an ampoule 32 filled with monomer liquid and a spatula 34 for mixing cement powder and monomer liquid in a mixing cup 26. Then, before being introduced into the mold or the lower part of the mold 1, the bone cement paste 36 can be mixed in the mixing cup 26. However, the bone cement paste 36 can also be made in other ways before being introduced into the mold. Therefore, the device does not necessarily require a mixing cup 26, nor does it require a bone cement paste 36 or its starting components. The device can be applied and used in principle with any other known system for making bone cement paste, for example, with a suitable cartridge system for storing and mixing bone cement paste.

[0184] Refer to the following Figure 1-11 The process of a first exemplary embodiment of a method according to the present invention is described.

[0185] The device may first be removed from its sterile packaging (not shown) and then may be used as Figure 1 Medium or Figure 3Or as shown in Figure 4. If the mold lower part 1 has not yet been inserted into the support 16, the mold lower part 1 can be pushed into the support 16 through the groove 21. If not yet, the metal core 10 can be inserted into the cavity 2 (see Figure 3 ). In this way, the protruding end of the spacer element 12 slides in the groove 18 of the mold wall 3.

[0186] The cement powder from the film bag 30 and the monomer liquid from the ampoule 32 are mixed in the mixing cup 26 by means of a spatula 34 to form a bone cement paste 36. Alternatively, the bone cement paste 36 may be made in any other manner.

[0187] When the metal core 10 is inserted into the cavity 2 or the inner space 4, the bone cement paste mass 36 may be excessively introduced into the inner space 4 and the cavity 2 (see Figure 4 ). The mold upper part 5 can then be inserted and pushed into the mold lower part 1 or into the mold wall 3. For this purpose, the container 7 can be closed with a cover 9 (see Figure 5 ).

[0188] The mold upper part 5 can be pushed into the interior space 4 of the mold lower part 1 until the mating stop 22 abuts against the limit stop 20 (see Figure 6 and Figure 7 , the bone cement paste mass enclosed in the mold is not shown in the figure). When the upper mold part 5 is pushed in, the existing bone cement paste mass 36 can be pressed into the mold cavity 2, and the volume in the mold is continuously reduced. The excess bone cement paste mass 38 is pressed out through the opening 8 and enters the container 7 (see Figure 8 and 9 ). With the help of the cover 9, the excess bone cement paste ball 38 can be enclosed in the container 7.

[0189] The bone cement paste 36 can then be cured in the mold, wherein its surface is molded by the surface of the mold cavity 2 of the lower mold part 1 and the molding surface 6 of the upper mold part 5. This results in, for example, Fig.10 and 1142. During the curing process of the bone cement paste mass 36, a gate 40 connecting the spacer 42 and the excess bone cement paste mass 38 cured in the container 7 can be formed in the opening 8. The spacer 42 is demoulded by separating from the lower part 1 of the mold and the upper part 5 of the mold. In this way, the gate 40 can be cut off or broken off. To ensure direct demoulding, the diameter of the gate 40 must be small enough to be manually broken or cut off when the spacer 42 is separated from the upper part 5 of the mold. It has been proven that the diameter of the gate 40 is 2.5 cm at most and preferably 2 cm at most for this purpose. Therefore, the inner diameter of the opening 8 should be 2.5 cm at most, preferably 2 cm. A smaller diameter can also be selected to further simplify the separation of the gate 40. However, the diameter of the opening 8 should not be less than 0.2 mm so that the bone cement paste mass 36 can still be pressed out through the opening 8 without excessive resistance. Otherwise, depending on the viscosity of the bone cement paste mass 36, the resistance when pushing the upper mold part 5 into the lower mold part 1 may become too great, so that it may still be necessary to do it manually, or damage or destruction of the mold may occur, which should be avoided. The optimal diameter of the opening 8 depends on the viscosity of the bone cement paste mass 36 used. For typical bone cements, a highly suitable diameter is between 1 mm and 20 mm. According to experience, the higher the viscosity of the bone cement paste mass 36, the larger the inner diameter of the selected opening 8 should be.

[0190] After demoulding, the protruding spacing parts 12, any burrs formed at the junction between the lower mold part 1 and the upper mold part 5, and the protruding remains of the gate 40 can be removed, for example by trimming them with a knife or a scalpel or grinding them off with a grinding head. Fig.11 The spacer 42 is shown.

[0191] Figures 12 to 22 is a diagram showing various views of a second exemplary embodiment of an apparatus for making a shoulder joint spacer according to the present invention, components of the apparatus, and a spacer made using the apparatus. Figures 12 to 18 22 show the process of a second exemplary embodiment of a method according to the present invention, which is performed using a device according to the second exemplary embodiment.

[0192] A second device according to the invention is suitable and provided for making a spacer 92 of a shoulder joint (see Fig.17 and 18 The device comprises a multi-part casting mold. The casting mold comprises a casting mold lower part 51 and a casting mold upper part 55. A mold cavity 52 is provided in the casting mold lower part 51 for receiving a bone cement paste mass 36 (see Figures 12 to 15) and is used to form a partial surface of the spacer 92 to be made. The cavity 52 can shape half of the spacer 92. The mold wall 53 can be arranged at the edge of the cavity 52, and the mold wall extends the hollow space formed by the cavity 52 and the inner space 54. The mold wall 53 can surround the edge of the cavity 52 circumferentially for this purpose. The walls of the mold wall 53 can be oriented parallel to each other so that the mold wall 53 has a roughly cylindrical geometry, wherein the roughly cylindrical bottom area is defined by the area that defines the edge of the cavity 52. ​​The inner space 54 for introducing the bone cement paste mass 36 is arranged in the wall of the mold wall 53, and the inner space is connected to the cavity 52 and is preferably aligned with the cavity 52.

[0193] The upper mold part 55 can preferably be inserted or pushed into the lower mold part 51. The upper mold part 55 has a molding surface 56 at its bottom, with which a further part of the surface of the spacer 92 to be produced is moldable, preferably the remaining part of the surface of the spacer 92 to be produced is moldable. Together with the cavity 52, the molding surface 56 can define the entire surface of the spacer 92 or at least 90% of the entire surface of the spacer 92. The molding surface 56 can form an impression in the upper mold part 55. It is also possible that a part of the mold wall 53 forms a part of the surface of the spacer 92, or that one or more inserts (not shown) that mold a part of the surface of the spacer 92 are inserted into the cavity 52 and / or placed on the molding surface 56.

[0194] For receiving excess bone cement paste 38 (see Fig. 22 ) can be arranged on the side of the upper part 55 of the mold opposite to the molding surface 56. There can be openings 58 in the molding surface 56, which provide a connection channel for the excess bone cement paste mass 38 from one side of the molding surface 56 to the container 57. The openings 58 are preferably arranged at points of the molding surface 56, which are the highest molding points of the mold in the appropriate configuration of the device. In this way, the gas trapped in the mold can escape through the openings 58, thereby avoiding the residual air in the spacer 92 to be made.

[0195] The container 57 can be or has been closed with a cover 59 in such a way that the cement mass 36 is impermeable to the outside. The inner wall 61, which delimits the container 57, can start from the back of the molding surface 56 and extend from the back. The inner wall 61 can be aligned with the mold wall 53 on the outside in a completely fitting manner. In this way, the mold upper part 55 can be inserted into the mold wall 53 of the mold lower part 51 in a completely fitting manner, and the bone cement mass 36 is accordingly gathered from the inside of the mold wall 53 and pressed into the mold cavity 52 and the molding surface 56. It is also sufficient to achieve this purpose if the mold wall 53 tapers in the direction of the mold cavity 52, wherein the angle of taper must be an acute angle.

[0196] The container 57 can be connected to the surrounding environment in a gas-permeable manner. For this purpose, it is conceivable that the cover 59 is not hermetically closed and / or that small ventilation openings (not visible in the figure) are provided on the cover and / or the inner wall 61.

[0197] A metal core 60 may be provided as a reinforcement for the spacer 92. To this end, the metal core 60 may be spaced apart from the inside of the cavity 52 and the mold wall 53 by means of the solidified PMMA pin-shaped spacer element 62, so that the bone cement paste ball 36 may flow completely around the metal core 60 between the metal core 60 and the inside of the cavity 52 and between the metal core 60 and the molding surface 56. To position the spacer element 62, a hole (not visible) may be provided in the metal core 60 for receiving one end of the pin-shaped spacer element 62. Likewise, a mating indentation may also be provided on the inside of the cavity 52 for receiving the other end of the pin-shaped spacer element 62.

[0198] A support 66 may be provided into which the mold lower part 51 may be placed or inserted in order to position the mold correctly with the mold lower part 51 below and the mold wall 53 vertically above. The support 66 may be provided to be placed on a flat surface, such as a table.

[0199] The mold bottom part 51, the mold top part 55, the cover 59 and the support 66 can be made of a plastic film or a plurality of plastic films connected together at low cost, in particular by injection molding or thermoforming. In the assembled state, the parts of the device made of plastic film are mechanically stabilized against each other. The plastic film preferably consists of polyolefins, polyethylene (PET) or ethylene glycol-modified PET (PETG). When a plurality of films are used, they can be laminated together with an adhesive or by high temperature.

[0200] Internal grooves 68 and external gates 69 may be provided in the mold wall 53, extending downward from a limit stop 70 on the side of the mold wall 53 opposite to the cavity 52 to the edge of the cavity 52. ​​The gate 69 may include a space for forming the grooves 68. The ends of the pin-shaped spacing members 62 extending from the metal core 60 may be guided to the cavity 52 along these grooves 68.

[0201] A groove 71 matching the gate 69 may be provided inside the bracket 66. Therefore, the mold lower part 51 can be pushed into the bracket 66 in a guided manner, and the mold lower part 51 is not so easy to separate from the bracket 66, nor is it so easy to move relative to the bracket 66.

[0202] To secure the spacing elements 62 and thus the metal core 60 in place, matching recesses 73 may be provided at the edge of the molding surface 56 of the mold upper part 55. The recesses 73 may be provided at the edge of the molding surface 56 so that when the mold upper part 55 is pushed into the mold wall 53 of the mold lower part 51, they move along the grooves 68 of the mold wall 53. The ends of the spacing elements 62 extending from the metal core 60 are accordingly clamped in the mold and located between the mold upper part 55 and the mold lower part 51.

[0203] The limit stop 70 can be provided as a circumferential strip-shaped edge extending vertically from the mold wall 53 on the side of the mold wall 53 facing away from the mold cavity 52. ​​The limit stop 70 can limit the extent to which the mold upper part 55 can be pushed into the mold lower part 51. To this end, the mold upper part 55 can have a counter-stop 72 in the form of a circumferential edge extending vertically from the inner wall 61 and arranged on the side of the inner wall 61 opposite to the molding surface 56. When the mold upper part 55 is fully pushed into the mold lower part 51, the counter-stop 72 abuts against the limit stop 70. In the same way, a cover edge 74 can be provided on the cover 59, which can be placed on the side of the counter-stop 72 opposite to the limit stop 70. Since the limit stop 70, the counter stop 72 and the cover edge 74 extend at an angle from the adjacent parts, the shapes of the molded lower part 51, the molded upper part 55 and the cover 59 are mechanically stabilized in the assembled state. This is particularly helpful if these parts are made from a plastic film or a plurality of plastic films by thermoforming.

[0204] The apparatus may also include a mixing cup 26 having a spout 28 for pouring the bone cement paste 36 from the mixing cup 26 (see Fig.14 ). The device may also include the starting components of the bone cement paste 36 contained in a separate container (not shown). Then, before being introduced into the casting mold or the lower part 51 of the casting mold, the bone cement paste 36 can be mixed in the mixing cup 26. However, the bone cement paste 36 can also be made in other ways before being introduced into the casting mold. Therefore, the device does not necessarily require a mixing cup 26, nor does it require the bone cement paste 36 or its starting components. The device can be applied and used in principle with any other known system for making bone cement paste, for example, with a suitable cylindrical system for storing and mixing bone cement paste.

[0205] Refer to the following Figure 12-22 The process of a second exemplary embodiment of the method according to the present invention is described.

[0206] The device may first be removed from a sterile packaging (not shown) and then may be used as Fig.12 or Fig.13If the mold lower part 51 has not yet been inserted into the bracket 66, the mold lower part 51 can be pushed into the bracket 66 through the groove 71. If not yet, the metal core 60 can be inserted into the cavity 52 (see Fig.13 ). In this way, the protruding end of the spacer member 62 slides in the groove 68 of the mold wall portion 53.

[0207] When the metal core 60 is inserted into the cavity 52 or the interior 54, the bone cement paste 36 may be excessively introduced into the interior space 54 and the cavity 52 (see FIG. Fig.14 ). The mold upper part 55 can then be inserted and pushed into the mold lower part 51 or the mold wall 53. For this purpose, the container 57 can be closed with a cover 59 (see Fig.15 ).

[0208] The mold upper part 55 can be pushed into the interior space 54 of the mold lower part 51 until the mating stop 72 abuts against the limit stop 70 (see Fig.16 , 20 and Fig.21 The bone cement paste mass enclosed in the mold is not shown in the figure. Fig. 20 and 21 ) or where the bone cement mass is not visible ( Fig.16 )). When the upper mold part 55 is pushed in, the existing bone cement paste mass 36 can be pressed into the mold cavity 52, and the volume in the mold continues to decrease. The excess bone cement paste mass 38 is pressed out through the opening 58 and into the container 57 (see Fig. 22 ). With the help of the cover 59, the excess bone cement paste ball 38 can be enclosed in the container 57.

[0209] The bone cement paste 36 can then be cured in the mold, wherein its surface is molded by the surface of the mold cavity 52 of the mold lower part 51 and the molding surface 56 of the mold upper part 55. This results in, for example, Fig.17 and 1892 shown in the figure. During the curing process of the bone cement paste mass 36, a gate 90 can be formed in the opening 58, which connects the spacer 92 and the excess bone cement paste mass 38 cured in the container 57. The spacer 92 is demoulded by separating from the mold lower part 51 and the mold upper part 55. In this way, the gate 90 can be cut off or broken. In order to ensure direct demoulding, the diameter of the gate 90 must be small enough to be manually broken or cut off when the spacer 92 is separated from the mold upper part 55. It has been proven that the diameter of the gate 90 is 2.5 cm at most and preferably 2 cm at most for this purpose. Therefore, the inner diameter of the opening 58 should be 2.5 cm at most, preferably 2 cm at most. A smaller diameter can also be selected to further simplify the separation of the gate 90. However, the diameter of the opening 58 should not be less than 0.2 mm so that the bone cement paste mass 36 can still be pressed out through the opening 58 without excessive resistance. Otherwise, depending on the viscosity of the bone cement paste mass 36, the resistance when the mold upper part 55 is pushed into the mold lower part 51 may become too large, thereby still may need to be carried out manually, or damage or destruction to the mold that should be avoided is generated. The optimal diameter of the opening 58 depends on the viscosity of the bone cement paste mass 36 used. For typical bone cement, the highly suitable diameter is between 1 mm and 20 mm. According to experience, the higher the viscosity of the bone cement paste mass 36, the larger the internal diameter of the selected opening 58 should be.

[0210] After demolding, the protruding spacing parts 62, any burrs formed at the interface between the lower mold part 51 and the upper mold part 55, and the protruding remains of the gate 90 can be removed, for example, by trimming them with a knife or a scalpel or grinding them with a grinding head. Fig.18 Spacer 92 is shown.

[0211] Figures 23 to 35 are diagrams showing a third exemplary embodiment of an apparatus for making a knee spacer according to the present invention, components of the spacer and various views of the components of the apparatus. Figures 23 to 31 The procedure of a third exemplary embodiment of a method according to the invention is shown, the method being carried out using a device according to the third exemplary embodiment.

[0212] A third device according to the invention is suitable and provided for making a two-part articulated spacer, which comprises a spacer 142 for the femur and a spacer 192 for the tibia (see Fig.31 and 34 ), an articulated spacer is used to replace the knee joint. The device has two multi-part castings, namely, a femoral component casting (in Figure 23-28 , 30-32 and 35 are located on the left side, Fig.29 and 33) for making a tibial component casting mold of the tibial spacer 192 (at the top of Figure 23-28 , 30-32 and 35 are located on the right side, Fig.29 and 33 For the purposes of the present invention, the third exemplary embodiment may also be understood as two different apparatuses according to the present invention, namely a fourth apparatus for making a femoral spacer 142 and a fifth apparatus for making a tibial spacer 192.

[0213] The femoral component casting mold comprises a casting lower part 101 and a casting upper part 105. A mold cavity 102 is provided in the casting lower part 101 for receiving a bone cement paste mass 36 (see Figure 23-25 , 29 and 33) and is used to form a partial surface of the spacer 142 to be made. The cavity 102 can shape half of the spacer 142. The mold wall 103 can be arranged at the edge of the cavity 102, and the mold wall extends the hollow space formed by the cavity 102 and the inner space 104. The mold wall 103 can surround the edge of the cavity 102 circumferentially for this purpose. The walls of the mold wall 103 can be oriented parallel to each other so that the mold wall 103 has a roughly cylindrical geometry, wherein the bottom area of ​​the roughly cylindrical shape is limited by the area that defines the edge of the cavity 102. The inner space 104 for introducing the bone cement paste mass 36 is arranged in the wall of the mold wall 103, and the inner space is connected to the cavity 102 and is preferably also aligned with the cavity 102.

[0214] The upper mold part 105 can preferably be inserted or pushed into the lower mold part 101. The upper mold part 105 has a molding surface 106 at its bottom, with which a further part of the surface of the spacer 142 to be produced can be molded, preferably the remaining part of the surface of the spacer 142 to be produced can be molded. Together with the cavity 102, the molding surface 106 can define the entire surface of the spacer 142 or at least 90% of the entire surface of the spacer 142. The molding surface 106 can form an impression in the upper mold part 105. It is also possible that a part of the mold wall 103 forms a part of the surface of the spacer 142, or that additionally one or more inserts (not shown) that shape a part of the surface of the spacer 142 are inserted into the cavity 102 and / or placed on the molding surface 106.

[0215] For receiving excess bone cement paste 38 (see Fig.29) container 107 can be arranged on the side of the mold upper part 105 opposite to the molding surface 106. An opening 108 in the form of a channel in the inner wall 111 of the mold upper part 105 can be present in the molding surface 106, and the opening provides a through connection from one side of the molding surface 106 to the container 107 for the redundant bone cement paste mass 38. The opening 108 is preferably arranged at a point of the molding surface 106, which is the highest molding point of the femoral component mold in the appropriate configuration of the device. Like this, the gas entrained in the femoral component mold can escape through the opening 108, thereby avoiding residual air in the spacer 142 to be made.

[0216] The container 107 can be or has been closed with a cover 109 so that the cement mass 36 is impermeable to the outside. The inner wall 111, which delimits the container 107, can start from the back of the molding surface 106 and extend from the back. The inner wall 111 can be aligned with the mold wall 103 on the outside in a completely fitting manner. In this way, the mold upper part 105 can be inserted into the mold wall 103 of the mold lower part 101 in a completely fitting manner, and the cement mass 36 is accordingly gathered from the inside of the mold wall 103 and pressed into the mold cavity 102 and the molding surface 106. It is also sufficient to achieve this purpose if the mold wall 103 tapers in the direction of the mold cavity 102, wherein the angle of the taper must be an acute angle.

[0217] The container 107 can be connected to the surrounding environment in a gas-permeable manner. For this purpose, it is conceivable that the cover 109 is not hermetically closed and / or that small ventilation openings (not visible in the figure) are provided on the cover and / or the inner wall 111.

[0218] According to a preferred variation of the third exemplary embodiment, a support 116 may be provided, into which the mold lower part 101 may be placed or inserted, in order to properly position the femoral component mold, with the mold lower part 101 at the bottom and the mold wall 103 vertically at the top (see FIG. Fig.32 and 33 ). The bracket 116 may be provided to be placed on a flat surface, such as a table.

[0219] The mold bottom part 101, the mold top part 105, the cover 109 and the support 116 can be made inexpensively from a plastic film or a plurality of plastic films connected together, in particular by injection molding or thermoforming. In the assembled state, the parts of the device made of plastic film are mechanically stabilized against each other. The plastic film preferably consists of polyolefins, polyethylene (PET) or ethylene glycol-modified PET (PETG). When a plurality of films are used, they can be laminated together with an adhesive or by high temperature.

[0220] The limit stop 120 may be arranged as a circumferential strip-shaped edge extending vertically from the mold wall 103 on the side of the mold wall 103 remote from the mold cavity 102. The limit stop 120 may limit the extent to which the mold upper part 105 can be pushed into the mold lower part 101. To this end, the mold upper part 105 may have a counter-stop 122 in the form of a circumferential edge, which extends vertically from the inner wall 111 and is arranged on the side of the inner wall 111 opposite to the molding surface 106. When the mold upper part 105 is fully pushed into the mold lower part 101, the counter-stop 122 abuts against the limit stop 120. In the same way, a cover edge 124 may be provided on the cover 109, which cover edge may be placed on the side of the counter-stop 122 opposite to the limit stop 120. Since the limit stop 120, the counter stop 122 and the cover edge 124 protrude from the adjacent parts at a certain angle, the shape of the mold bottom part 101, the mold top part 105 and the cover 109 is mechanically stable in the assembled state. This is particularly beneficial if these parts are made of plastic film or multiple plastic films by thermoforming.

[0221] The structure of the tibial component casting mold is similar to that of the femoral component casting mold, and has a casting mold lower part 151 and a casting mold upper part 155. A mold cavity 152 is provided in the casting mold lower part 151 for receiving the bone cement paste mass 36 (see Figure 23-25 , 29 and 33) and is used to form a partial surface of the spacer 192 to be made. The cavity 152 can shape half of the spacer 192. The mold wall 153 can be arranged at the edge of the cavity 152, and the mold wall extends the hollow space formed by the cavity 152 and the inner space 154. The mold wall 153 can surround the edge of the cavity 152 circumferentially for this purpose. The walls of the mold wall 153 can be oriented parallel to each other, whereby the mold wall 153 has a roughly cylindrical geometry, wherein the bottom area of ​​the roughly cylindrical shape is limited by the area that defines the edge of the cavity 152. The inner space 154 for introducing the bone cement paste mass 36 is arranged in the wall of the mold wall 153, and the inner space is connected to the cavity 152 and is preferably also aligned with the cavity 152.

[0222] The upper mold part 155 can preferably be inserted or pushed into the lower mold part 151. The upper mold part 155 has a molding surface 156 at its bottom, with which a further part of the surface of the spacer 192 to be produced can be molded, preferably the remaining part of the surface of the spacer 192 to be produced can be molded. Together with the cavity 152, the molding surface 156 can define the entire surface of the spacer 192 or at least 90% of the entire surface of the spacer 192. The molding surface 156 can form an impression in the upper mold part 155. It is also possible that a part of the mold wall 153 forms a part of the surface of the spacer 192, or that additionally one or more inserts (not shown) that shape a part of the surface of the spacer 192 are inserted into the cavity 152 and / or placed on the molding surface 156.

[0223] For receiving excess bone cement paste 38 (see Fig.29 ) container 157 can be arranged on the side of the upper part 155 of the casting mold opposite to the molding surface 156. There can be openings 158 in the molding surface 156, which provide a through connection from one side of the molding surface 156 to the container 157 for the excess bone cement paste mass 38. The openings 158 are preferably arranged at points of the molding surface 156, which are the highest molding points of the tibial component casting in the appropriate configuration of the device. In this way, the gas trapped in the tibial component casting can escape through the openings 158, thereby avoiding the residual air in the spacer 192 to be made.

[0224] The container 157 can be or has been closed with a cover 159 so that the bone cement paste mass 36 is impermeable to the outside. The inner wall 161, which delimits the container 157, can start from the back of the molding surface 156 and extend from the back. The inner wall 161 can be aligned with the mold wall 153 on the outside in a completely fitting manner. In this way, the mold upper part 155 can be inserted into the mold wall 153 of the mold lower part 151 in a completely fitting manner, and the bone cement paste mass 36 is accordingly gathered from the inside of the mold wall 153 and pressed into the mold cavity 152 and the molding surface 156. It is also sufficient to achieve this purpose if the mold wall 153 tapers in the direction of the mold cavity 152, wherein the angle of taper must be an acute angle.

[0225] The container 157 can be connected to the surrounding environment in a gas-permeable manner. For this purpose, it is conceivable that the cover 159 is not hermetically closed and / or that a small ventilation opening (not visible in the figure) is provided on the cover and / or the inner wall 161.

[0226] According to a preferred variation of the third exemplary embodiment, a bracket 166 may be provided into which the mold lower part 151 may be placed or inserted in order to properly position the tibial component mold, with the mold lower part 151 at the bottom and the mold wall 153 vertically at the top (see FIG. Fig.32 and 33 ). The bracket 166 may be provided to rest on a flat surface, such as a table.

[0227] The mold bottom part 151, the mold top part 155, the cover 159 and the support 166 can be made of a plastic film or a plurality of plastic films connected together at low cost, in particular by injection molding or thermoforming. In the assembled state, the parts of the device made of plastic film are mechanically stabilized against each other. The plastic film preferably consists of polyolefin, polyethylene (PET) or ethylene glycol-modified PET (PETG). When a plurality of films are used, they can be laminated together with an adhesive or by high temperature.

[0228] The limit stop 170 can be provided as a circumferential strip-shaped edge extending vertically from the mold wall 153 on the side of the mold wall 153 away from the mold cavity 152. The limit stop 170 can limit the extent to which the mold upper part 155 can be pushed into the mold lower part 151. To this end, the mold upper part 155 can have a mating stop 172 in the form of a circumferential edge, which extends vertically from the inner wall 161 and is provided on the side of the inner wall 161 opposite to the molding surface 156. When the mold upper part 155 is fully pushed into the mold lower part 151, the mating stop 172 abuts against the limit stop 170. In the same way, a cover edge 174 can be provided on the cover 159, which can be placed on the side of the mating stop 172 opposite to the limit stop 170. Since the limit stop 170, the counter stop 172 and the cover edge 174 protrude at an angle from the adjacent parts, the shape of the molded lower part 151, the molded upper part 155 and the cover 159 is mechanically stable in the assembled state. This is particularly advantageous if these parts are made of a plastic film or a plurality of plastic films by thermoforming.

[0229] The apparatus may further include a mixing cup 26 having a spout 28 for pouring the bone cement paste 36 from the mixing cup 26 (see Fig.23 ), as well as a film bag 30 filled with cement powder, an ampoule 32 filled with monomer liquid and a spatula 34 for mixing cement powder and monomer liquid in a mixing cup 26. Then, before being introduced into the mold or the lower part of the mold 1, the bone cement paste 36 can be mixed in the mixing cup 26. However, the bone cement paste 36 can also be made in other ways before being introduced into the mold. Therefore, the device does not necessarily require a mixing cup 26, nor does it require a bone cement paste 36 or its starting components. The device can be applied and used in principle with any other known system for making bone cement paste, for example, with a suitable cylindrical system for storing and mixing bone cement paste.

[0230] Refer to the following Figure 23-35The procedure of a third exemplary embodiment of the method according to the present invention is described.

[0231] The device may first be removed from a sterile packaging (not shown) and then may be used as Fig.23 or Fig.25 If a support 116 , 166 is present, the mold lower part 101 , 105 is optionally inserted into the support 116 , 166 .

[0232] By mixing the cement powder from the film bag 30 and the monomer liquid from the ampoule 32 in the mixing cup 26 by means of a spatula 34, a bone cement paste 36 can be mixed. In addition, the bone cement paste 36 can also be made in any other way.

[0233] Then, excess amounts of bone cement paste 36 may be introduced into the interior space 104 and the cavity 102 and into the interior space 154 and the cavity 152, respectively (see FIG. Fig.25 ). Then, the mold upper part 105 can be inserted and pushed into the mold lower part 101, and the mold upper part 155 can be inserted into the mold lower part 151. To this end, the container 107 can be closed with the cover 109, and the container 157 can be closed with the cover 159 (see Fig.26 and 27 ).

[0234] The mold upper part 105 can be pushed into the interior space 104 of the mold lower part 101 until the mating stop 122 abuts against the limit stop 120, and the mold upper part 155 can be pushed into the interior space 154 of the mold lower part 151 until the mating stop 172 abuts against the limit stop 170 (see in this regard Fig.28 and 29 ). When the upper mold parts 105, 155 are pushed in, the existing bone cement paste 36 can be pressed into the mold cavity 102, 152, and the space in the femoral component mold and the tibial component mold is continuously reduced. The excess bone cement paste 38 is pressed out through the openings 108, 158 and enters the container 107, 157 (see Fig.29 ). With the help of the cover 109, 159, the excess bone cement paste 38 can be enclosed in the container 107, 157.

[0235] Then, the bone cement paste mass 36 in the femoral component casting mold and the tibial component casting mold can be cured, wherein its surface is molded by the surface of the mold cavity 102 of the casting mold lower part 101 and the molding surface 106 of the casting mold upper part 105 or by the surface of the mold cavity 152 of the casting mold lower part 151 and the molding surface 156 of the casting mold upper part 155. Thus, for example, Fig.31 and 34The spacer 142 for the femur and the spacer 192 for the tibia are shown. During the curing process of the bone cement paste ball 36, a gate 140 can be formed in the opening 108 to connect the femoral spacer 142 and the cured excess bone cement paste ball 38 in the container 107. Similarly, during the curing process of the bone cement paste ball 36, a gate 190 can be formed in the opening 158 to connect the tibial spacer 192 and the cured excess bone cement paste ball 38 in the container 157. The spacers 142, 192 are demolded by separating from the lower mold component 101, 151 and the upper mold component 105, 155. In this way, the gate 140, 190 can be cut off or broken off. In order to ensure direct demolding, the diameter of the gate 140, 190 must be small enough that the gate 140, 190 can be manually broken off or cut off when the spacer 142, 192 is separated from the upper mold component 105, 155. It has been proved that the diameter of gate 140,190 is effective for a maximum of 2.5 centimetres and preferably a maximum of 2 centimetres for this reason.Therefore, the internal diameter of opening 8 should be a maximum of 2.5 centimetres, preferably a maximum of 2 centimetres.Also can select smaller diameter, to further simplify the separation of gate 140,190.But the diameter of opening 108,158 should not be less than 0.2 millimetre, so that bone cement paste mass 36 can still be pressed out by opening 108,158 without producing too much resistance.Otherwise, depending on the viscosity of bone cement paste mass 36, the resistance when mold upper part 105 is pushed into mold lower part 101 or the resistance when mold upper part 155 is pushed into mold lower part 151 may become too large, thereby still may need to carry out by hand, or may produce the damage or destruction to femoral component casting mold and tibial component casting mold that should be avoided.The optimum diameter of opening 108,158 depends on the viscosity of used bone cement paste mass 36 at this. For typical bone cement, the diameter of high suitability is between 1 millimeter and 20 millimeters.According to experience, the higher the viscosity of the bone cement paste mass 36, the larger the inner diameter of the selected opening 108, 158 should be.

[0236] After demolding, any burrs formed at the interface between the lower mold part 101, 151 and the upper mold part 105, 155, as well as protruding residues of the gates 140, 190 can be removed, for example, by trimming with a knife or a scalpel or grinding with a grinding head. Fig.34 The spacers 142, 192 are shown.

[0237] The features of the invention disclosed in the above description and in the claims, drawings and exemplary embodiments can be applied separately or in any combination to realize various embodiments of the invention.

[0238] Reference numerals list

[0239] 1,51,101,151 Lower parts of mold

[0240] 2,52,102,152 Cavity

[0241] 3,53,103,153 Mold wall

[0242] 4,54,104,154 Interior Space

[0243] 5,55,105,155 Casting upper parts

[0244] 6,56,106,156 Molding surface

[0245] 7,57,107,157 Container

[0246] 8,58,108,158 Open

[0247] 9,59,109,159 Cover

[0248] 10,60 metal core

[0249] 11,61,111,161 Inner wall

[0250] 12,62 Spacer parts

[0251] 14 holes

[0252] 16,66,116,166 Bracket

[0253] 18,68 Grooves

[0254] 19,69 Gate

[0255] 20,70,120,170 Limit stop / contact surface

[0256] 21,71 Grooves

[0257] 22,72,122,172 Mating stop / contact surface

[0258] 23,73 recess

[0259] 24,74,124,174 Cover edge

[0260] 26 Mixing cup

[0261] 28 mouth

[0262] 30 Film bag filled with bone cement powder

[0263] 32 Ampoules containing monomer liquid

[0264] 34 Spatula

[0265] 36 Bone cement paste

[0266] 38 Excess bone cement paste

[0267] 40,90,140,190 Gate

[0268] 42,92,142,192 Spacers

[0269] 44,94 Spacer head

[0270] 46,96 Rod.

Claims

1. A device for making a spacer (42, 92, 142, 192) by solidifying a bone cement paste dough (36) in a casting mold, wherein: The spacer (42, 92, 142, 192) is provided in the medical field for temporary replacement of a joint or a joint part including a joint articulation surface, the device having: A casting mold lower part (1, 51, 101, 151), wherein the casting mold lower part (1, 51, 101, 151) has a cavity (2, 52, 102, 152) for receiving a bone cement paste dough (36) and a first surface area for molding the spacer (42, 92, 142, 192) from the bone cement paste dough (36); a mold wall (3, 53, 103, 153) extending circumferentially from a circumferential edge of a mold cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151) away from the mold cavity (2, 52, 102, 152) and being open on a side opposite to the mold cavity (2, 52, 102, 152) so that the mold cavity (2, 52, 102, 152) can be approached through an interior space (4, 54, 104, 154) defined by the mold wall (3, 53, 103, 153); A casting mold upper part (5, 55, 105, 155), wherein the casting mold upper part (5, 55, 105, 155) has a molding surface (6, 56, 106, 156) for molding the second surface area of ​​the spacer (42, 92, 142, 192) from a bone cement paste dough (36), wherein the casting mold upper part (5, 55, 105, 155) can be opened to the inner space (42, 92, 142, 192) through the open side of the casting mold wall (3, 53, 103, 153) opposite to the mold cavity (2, 52, 102, 152). , 54, 104, 154) and can be inserted into the mold cavity (2, 52, 102, 152) and can move in the direction of the mold cavity (2, 52, 102, 152) to form a hollow space, the hollow space is defined by the mold cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151), the molding surface (6, 56, 106, 156) of the mold upper part (5, 55, 105, 155) and the mold wall part (3, 53, 103, 153), and the spacer (42, 92, 142, 192) can be molded in the hollow space; at least one container (7, 57, 107, 157) for receiving excess bone cement paste (38); and At least one opening (8, 58, 108, 158) in the molding surface (6, 56, 106, 156) of the upper mold part (5, 55, 105, 155) and / or in the mold cavity (2, 52, 102, 152) of the lower mold part (1, 51, 101, 151), wherein the at least one opening (8, 58, 108, 158) leads to the at least one container (7, 57, 107, 157) for receiving excess bone cement paste (38), wherein The device has one or two covers (9, 59, 109, 159), By means of the cover, the upper part (5, 55, 105, 155) of the casting mold is or can be closed to the outside on the side of the upper part (5, 55, 105, 155) of the casting mold opposite to the molding surface (6, 56, 106, 156), so that an upper container closed to the outside is formed between the upper part (5, 55, 105, 155) of the casting mold and the cover (9, 59, 109, 159) to serve as one of the at least one container (7, 57, 107, 157) for receiving the bone cement paste dough (36), and / or By means of the cover, the lower part (1, 51, 101, 151) of the casting mold is or can be closed to the outside on the side of the lower part (1, 51, 101, 151) of the casting mold opposite to the mold cavity (2, 52, 102, 152), thereby forming a lower container closed to the outside between the lower part (1, 51, 101, 151) of the casting mold and the cover (9, 59, 109, 159) to serve as one of the at least one container (7, 57, 107, 157) for receiving the bone cement paste dough. The cover (9, 59, 109, 159) or one of the cover is or can be placed in or on the upper part of the mold (5, 55, 105, 155), or in or on the inner wall (11, 61, 111, 161) of the upper part of the mold (5, 55, 105, 155), so as to close the side opposite to the molding surface (6, 56, 106, 156) of the upper part of the mold (5, 55, 105, 155) to the outside and form a space for receiving excess bone water there. A closed container (7, 57, 107, 157) for a cement ball (38), and / or the cover (9, 59, 109, 159) or one of the covers is or can be placed in or on the lower part (1, 51, 101, 151) of the mold so as to close the side opposite to the cavity (2, 52, 102, 152) of the lower part (1, 51, 101, 151) of the mold to the outside and form a closed container (7, 57, 107, 157) for receiving excess bone cement ball (38).

2. The device according to claim 1, characterized in that Opposing parts of the mold wall (3, 53, 103, 153) are oriented parallel to each other, or the mold wall (3, 53, 103, 153) is slightly tapered in the direction of the cavity (2, 52, 102, 152), or the mold wall (3, 53, 103, 153) has an upright or inclined overall cylindrical shape, whose base area is bounded by the circumferential edge of the cavity (2, 52, 102, 152).

3. The device according to claim 1 or 2, characterized in that The inner wall (11, 61, 111, 161) of the upper mold part (5, 55, 105, 155) extends circumferentially from the circumferential edge of the molding surface (6, 56, 106, 156) of the upper mold part (5, 55, 105, 155) in a direction away from the cavity (2, 52, 102, 152) of the lower mold part (1, 51, 101, 151).

4. The device according to claim 3, characterized in that The inner wall (11, 61, 111, 161) at least partially delimits the at least one container (7, 57, 107, 157), and / or mutually opposing parts of the inner wall (11, 61, 111, 161) are oriented parallel to each other, or the inner wall (11, 61, 111, 161) has an upright or inclined overall cylindrical shape, the base area of ​​which is delimited by the circumferential edge of the molding surface (6, 56, 106, 156) of the upper part of the mold (5, 55, 105, 155).

5. The device according to claim 3, characterized in that When the mold upper part (5, 55, 105, 155) is pushed into the mold wall (3, 53, 103, 153), the inner wall (11, 61, 111, 161) and the mold wall (3, 53, 103, 153) rest flush with each other, and / or When the upper mold part (5, 55, 105, 155) is pushed into the mold wall (3, 53, 103, 153), the inner wall (11, 61, 111, 161) forms a seal for the bone cement paste ball (36) relative to the mold wall (3, 53, 103, 153).

6. The device according to claim 1 or 2, characterized in that The cover (9, 59, 109, 159) has at least one ventilation opening and / or the cover (9, 59, 109, 159) is or can be gas-permeably closed together with the casting mold upper part (5, 55, 105, 155).

7. The device according to claim 1 or 2, characterized in that The volume of the cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151) and the volume bounded by the mold wall (3, 53, 103, 153) are combined to be greater than the volume of the spacer (42, 92, 142, 192) to be produced.

8. The device according to claim 1 or 2, characterized in that The mold wall (3, 53, 103, 153) and the mold lower part (1, 51, 101, 151) are formed as one part.

9. The device according to claim 8, characterized in that The mold wall (3, 53, 103, 153) is part of the mold lower part (1, 51, 101, 151).

10. The device according to claim 1 or 2, characterized in that The device comprises a mixing system for mixing a bone cement dough (36), cement powder and a monomer liquid, wherein the cement powder and the monomer liquid are stored separately from one another, wherein the bone cement dough (36) can be mixed from the cement powder and the monomer liquid by means of the mixing system.

11. The device according to claim 10, characterized in that The mixing system comprises a mixing cup (26) having a mouth (28) for introducing a mass of bone cement (36) from the mixing cup (26) into a mold cavity (2, 52, 102, 152) and an interior space (4, 54, 104, 154) defined by a mold wall (3, 53, 103, 153), or The mixing system is a bone cement cartridge for storing and mixing cement powder and monomer liquid and for conveying the mixed bone cement dough (36) from the bone cement cartridge, wherein the bone cement cartridge contains the cement powder and the monomer liquid in separate areas in a fluid-tight manner.

12. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151) and the mold upper part (5, 55, 105, 155) and - if present - the cover (9, 59, 109, 159) consist of or consist essentially of a plastic film, or The mold lower part (1, 51, 101, 151) and the mold upper part (5, 55, 105, 155) and, if present, the cover (9, 59, 109, 159) each consist of two or more plastic films connected together.

13. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151) and the mold upper part (5, 55, 105, 155), also the mold wall (3, 53, 103, 153) and - if present - the cover (9, 59, 109, 159) consist of or essentially consist of a plastic film, or The mold bottom part (1, 51, 101, 151) and the mold top part (5, 55, 105, 155), as well as the mold wall (3, 53, 103, 153) and - if present - the cover (9, 59, 109, 159) are each composed of two or more plastic films welded or adhesively bonded together.

14. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151), the mold upper part (5, 55, 105, 155), the mold wall (3, 53, 103, 153) and - if present - the cover (9, 59, 109, 159) consist essentially or completely of plastic material.

15. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151), the mold upper part (5, 55, 105, 155), the mold wall (3, 53, 103, 153) and - if present - the cover (9, 59, 109, 159) are essentially or completely made of polyolefins, polyethylene (PE) or polypropylene (PP).

16. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151), the mold upper part (5, 55, 105, 155), the mold wall (3, 53, 103, 153) and - if present - the cover (9, 59, 109, 159) are essentially or completely made of PETG film and / or polyamide film and / or PE film.

17. The device according to claim 1 or 2, characterized in that The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at most 2.5 mm, and / or The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at least 0.2 mm.

18. The device according to claim 1 or 2, characterized in that The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at most 2 mm, and / or The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at least 0.5 mm.

19. The device according to claim 1 or 2, characterized in that The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at most 1.5 mm, and / or The at least one opening (8, 58, 108, 158) has a minimum cross-sectional length of at least 1 mm.

20. The device according to claim 1 or 2, characterized in that A limit stopper (20, 70, 120, 170) is arranged at one end of the mold wall (3, 53, 103, 153) opposite to the mold cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151) to limit the movement of the mold upper part (5, 55, 105, 155) in the direction of the mold cavity (2, 52, 102, 152) within the mold wall (3, 53, 103, 153).

21. The device according to claim 20, characterized in that The contact surface is arranged as a limit stop (20, 70, 120, 170) at the end of the mold wall (3, 53, 103, 153) opposite the mold cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151).

22. The device according to claim 21, characterized in that The contact surface projects at a right angle from the mold wall (3, 53, 103, 153).

23. The device according to claim 1 or 2, characterized in that The device has a metal core (10, 60) which is to be or has been arranged in a cavity (2, 52).

24. The device according to claim 23, characterized in that The device has a plurality of spacer elements (12, 62) which keep the metal core (10, 60) in the mold cavity (2, 52) spaced apart from the inside of the mold cavity (2, 52) and the inside of the mold wall (3, 53).

25. The device according to claim 24, characterized in that The spacer element (12, 62) consists of cured bone cement.

26. The device according to claim 24, characterized in that The spacer element (12, 62) consists of cured polymethyl methacrylate.

27. The device according to claim 1 or 2, characterized in that The mold lower part (1, 51, 101, 151) or the mold upper part (5, 55, 105, 155) and the mold wall (3, 53, 103, 153), or the mold lower part (1, 51, 101, 151), the mold wall (3, 53, 103, 153) and the mold upper part (5, 55, 105, 155) are each or all transparent or translucent.

28. The device according to claim 1 or 2, characterized in that The at least one opening (8, 58, 108, 158) is arranged in a region of the casting mould which, in the normal configuration, is the highest point of the hollow space.

29. The device according to claim 1 or 2, characterized in that The outer edge of the molding surface (6, 56, 106, 156) of the mold upper part (5, 55, 105, 155) rests internally on the mold wall (3, 53, 103, 153) and when the mold upper part (5, 55, 105, 155) is pushed in, the edge slides internally on the mold wall (3, 53, 103, 153).

30. The device according to claim 29, characterized in that The edge has a scraping edge or scraping lip.

31. The device according to claim 1 or 2, characterized in that The device has a support (16, 66, 116, 166), wherein a mold lower part (1, 51, 101, 151) can be inserted into the support (16, 66, 116, 166), and the support (16, 66, 116, 166) is suitable for being placed on a flat support together with the mold lower part (1, 51, 101, 151) in the support.

32. The device according to claim 31, characterized in that The support (16, 66, 116, 166) is substantially or completely composed of a plastic film or of two or more plastic films connected together.

33. The device according to claim 31, characterized in that The support (16, 66, 116, 166) is substantially or completely composed of a plastic film or of two or more plastic films welded or bonded together.

34. The device according to claim 1 or 2, characterized in that The joint is a hip joint, a knee joint or a shoulder joint.

35. A method for making a spacer (42, 92, 142, 192) for temporarily replacing a joint or a portion of a joint including a joint articulating surface, wherein: The method is carried out using a device according to any one of claims 1 to 33, and comprises the following steps in chronological order: A) introducing a flowable bone cement paste mass (36) into the mold cavity (2, 52, 102, 152) and the inner space (4, 54, 104, 154) defined by the mold wall portion (3, 53, 103, 153), wherein the volume of the introduced flowable bone cement paste mass (36) is greater than the volume required for the spacer (42, 92, 142, 192); B) inserting a mold upper part (5, 55, 105, 155) into a mold wall (3, 53, 103, 153), wherein the molding surface (6, 56, 106, 156) points in the direction of the mold cavity (2, 52, 102, 152); C) pushing the upper mold part (5, 55, 105, 155) into the mold wall (3, 53, 103, 153) in the direction of the mold cavity (2, 52, 102, 152); D) when the upper part (5, 55, 105, 155) of the casting mold is continuously pushed in, the excess bone cement paste (38) overflows through the at least one opening (8, 58, 108, 158), wherein the excess bone cement paste (38) flows into the at least one container (7, 57, 107, 157) for receiving the excess bone cement paste (38); E) when the desired height of the spacer (42, 92, 142, 192) is reached, the pushing is terminated; F) allowing the bone cement paste (36) to solidify in the hollow space formed by the mold cavity (2, 52, 102, 152), the molding surface (6, 56, 106, 156) of the upper part of the mold (5, 55, 105, 155) and the wall part (3, 53, 103, 153), and G) Removing the spacer (42, 92, 142, 192) molded and cured in this manner from the hollow space, wherein the gate (40, 90, 140, 190) of the cured bone cement paste dough (36) formed in the at least one opening (8, 58, 108, 158) is separated.

36. The method according to claim 35, characterized in that In step D), the excess bone cement paste mass (38) flows into a lower container for receiving the excess bone cement paste mass (38) on the lower part (1, 51, 101, 151) of the casting mold and is closed by a cover (9, 59, 109, 159), and is closed in the lower container, and / or flows into an upper container (7, 57, 107, 157) for receiving the excess bone cement paste mass (38) on the upper part (5, 55, 105, 155) of the casting mold and is closed by a cover (9, 59, 109, 159), and is closed in the upper container, wherein: When the cured spacer (42, 92, 142, 192) is demolded after step F) or in step G), the cured excess bone cement mass (38) remains in the lower container and / or the upper container (7, 57, 107, 157).

37. The method according to claim 35 or 36, characterized in that Before step A), the monomer liquid and cement powder are mixed into a bone cement paste (36) until a uniform bone cement paste (36) is obtained.

38. The method according to claim 35 or 36, characterized in that Prior to step A), a metal core (10, 60) is arranged in the mold cavity (2, 52).

39. The method according to claim 38, characterized in that The metal core (10, 60) is spaced apart from the inner wall of the mold cavity (2, 52) and the mold wall (3, 53) by means of pin-shaped spacer parts (12, 62).

40. The method according to claim 35 or 36, characterized in that During step C), air is exhausted from a hollow space defined by the cavity (2, 52, 102, 152) of the mold lower part (1, 51, 101, 151), the molding surface (6, 56, 106, 156) of the mold upper part (5, 55, 105, 155) and the mold wall (3, 53, 103, 153) through the at least one opening (8, 58, 108, 158).

41. The method according to claim 35 or 36, characterized in that After step F) and before step G), the upper mold part (5, 55, 105, 155) is removed from the open end of the mold wall (3, 53, 103, 153).

42. The method according to claim 35 or 36, characterized in that The joint is a hip joint, a knee joint or a shoulder joint.

43. The method according to claim 35 or 36, characterized in that The method is carried out with the device according to claim 20, wherein in step E), the insertion is terminated when a limit stop (20, 70, 120, 170) is reached.

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