WO2013135361A1

WO2013135361A1 - Device for bone cement application, particularly for arthroprosthesis implants

Info

Publication number: WO2013135361A1
Application number: PCT/EP2013/000700
Authority: WO
Inventors: Daniele MONTANARO
Original assignee: Montanaro Daniele
Priority date: 2012-03-12
Filing date: 2013-03-08
Publication date: 2013-09-19
Also published as: ITMI20120385A1

Abstract

A device for bone cement application (1), particularly for arthroprosthesis implants, which comprises a box-like body (4) which has at least one open portion (12), and at least one closing element (2) which can be engaged with the open portion (12) of the box-like body (4). The box- like body (4) and the closing element (2) are adapted to contain a prosthesis component (3). The box-like body (4) and the closing element (2) define a gap (6) which adjoins at least one surface of the prosthesis component (3) which is engageable with at least one bone portion of a joint. The gap (6) is adapted to be filled in with bone cement.

Description

DEVICE FOR BONE CEMENT APPLICATION, PARTICULARLY FOR ARTHROPROSTHESIS IMPLANTS

The present invention relates to a device for bone cement application, particularly for arthroprosthesis implants.

Currently, several types of orthopedic implants are used for most of the joints of the human body, such as, for example, hip, knee, ankle, elbow, wrist, shoulder, skull and spine. These prostheses, commonly known as arthroprostheses, or endoprostheses, can be implanted in patients either by means of bone cement, or without bone cement. In the first case, they are called "cemented prostheses", in the second case they are called "uncemented prostheses" or "press-fit prostheses". Arthroprostheses can include one or more prosthetic components. In the case of knee prostheses, for example, these components can be the tibial component, the femoral component and the articulating insert. In the case of hip prostheses, such prosthetic components can be the femoral stem, the head, the acetabular cup, and the acetabular insert.

Bone cements are used to secure and to anchor the prosthesis to the bone, to ensure the primary stability of the prosthesis, to distribute the load from the prosthesis to the confining load transmission area of the bone, to ensure a shock-absorbing effect, to strengthen the bone structure, to correct and to stabilize defects, and finally to distribute locally various types of drugs, such as, for example, antibiotics.

In the case of cemented prostheses, today, there is a great deal of attention with regard to the preparation of the bone cement, since it is known that good cementation results in a longer life of the prosthetic implant itself. The optimal preparation of bone cement requires the bone cement to be homogeneously mixed, cleared from impurities and air inclusions, thus resulting in a cement with high mechanical properties. Nowadays, the bone cement is mainly manually applied to the prosthesis and to the surface of the bone of the joint where the prosthesis is to be implanted. For example, in the case of the so-called "re-surfacing" prostheses, i.e. prostheses without stems, which cover the bone of a joint, such as a primary knee prosthesis applied to the ends of the tibia and/or the femur, the known techniques of bone cement application require the bone cement to be applied to the prosthetic components directly by a medical operator, for example, the orthopedic surgeon, by hands, or, in some cases, by means of a spatula or the like.

In the case of hip prostheses, which have a stem, the known techniques of bone cement application require the bone cement to be suitably introduced into the intramedullary canal, and this operation, when not performed manually, is performed by means of a special pressure gun provided with cartridge containing bone cement. The cartridge nozzle is adapted to inject, by pressure, the bone cement into the bone cavity to be filled in.

The bone cement can be mixed with suitable dyes or pigments, such as Methylene blue or Chlorophyll, in order to color it, so that it can be clearly distinguished from the bone surrounding the prosthetic implant, and so that the cement in excess can be easily removed.

Such known techniques of bone cement application suffer drawbacks, such as the fact that a manual application of the bone cement is not free from errors that can affect the entire surgical operation and the prosthetic implant follow- up.

Another drawback of the known techniques consists in that the manual application of the cement does not allow an adequate distribution of the cement itself on the prosthetic components and/or on the corresponding joint bone portions, and it does not allow a distribution in appropriate quantities. It is indeed known that, once the prosthesis has been implanted, it is mandatory to remove the bone cement in excess, since it may restrict the range of movement of the movable components of the prosthetic implant itself. Furthermore, the presence of bone cement in excess can adversely affect the most delicate parts of a prosthesis, such as the polyethylene articulating inserts, whose mechanical wear would cause the release of free fragments of polyethylene which, in the most severe cases, could intrude between the bone and the prosthesis, causing an aseptic loosening of the prosthetic components (in medical jargon, "wear debris osteolysis").

A further drawback of such known techniques consists in that the issue of distributing adequately the cement over the entire surface of the prosthetic component, causes a prolongation of the operative session, and a corresponding increase of the risks of infections. It is indeed known that a longer wound exposure increases the risk of infection. Moreover also the need to carefully remove the cement in excess determines a prolongation of the operative session.

Another drawback of the known techniques is that when the cement is applied in excessive amounts, it can cover holes, hooks or other systems or mechanical parts that are used to put correctly into place the prosthetic implant, resulting in an inaccurate placement of the prosthesis.

A further drawback consists in that, when only small quantities of cement are applied, in order to prevent the following laborious removal of any cement in excess, the prosthesis can be unstable, and the risk of detachment of the same from the bone seat can be high.

Another drawback of the manual techniques of bone cement application regards the possible contamination of the sterile prosthetic components, caused by the fact that they have to be handled manually by the medical operator till all the bone cement has been adequately distributed. A further drawback regards the waste of bone cement, due to the fact that it is always difficult to predict the right amount of bone cement necessary for the prosthetic implant, and therefore bone cement is always prepared in excess. In the case of bone cement application into bone cavities formed to accommodate prosthetic stems, which is performed by means of pressure guns, a drawback consists in that the excessive pressure exerted by the bone cement injected into the bone cavity may cause embolisms and other serious consequences for the patient.

A further drawback of the known techniques of bone cement application, particularly when antibiotic loaded bone cement is adopted, in order to release locally antibiotic drugs, regards the problem of establishing the maximum percentage of antibiotic to be added to the bone cement. Because of the unpredictable amount of bone cement that will actually be applied onto the prosthesis and onto the bone, and/or subsequently removed, there is a risk of adding insufficient or excessive quantities of antibiotic, with serious consequences for the prosthetic implant follow-up.

The aim of the present invention consists in providing a device for bone cement application, particularly for arthroprosthesis implants, which solves the problems and the drawbacks mentioned above and which overcomes the limits of the prior art, by allowing a known and optimal quantity of bone cement to be distributed on the prosthetic component to be implanted, thus improving the prosthetic implant surgery and the prosthetic implant follow- up.

Within this aim, an object of the invention is to provide a device for bone cement application which reduces the need of handling manually the prosthetic components during surgery, thus reducing the risks of contamination and ensuring sterility. Another object of the invention consists in that the application of an adequate dose of bone cement prevents the problem of removing the bone cement in excess, thus eliminating also the problem that residual bone cement may limit the movement of the prosthetic joint or damage, injure or scratch the implanted prosthetic components.

A further object of the invention consists in that the application of an adequate dose of bone cement prevents the risk of premature loosening and detachment of the implanted prosthetic components.

Another object of the invention consists in speeding up the surgical preparation phases, thus reducing the duration of the surgery and therefore reducing the risks of infections for the patient.

A further object of the invention consists in optimizing the dose of bone cement to be prepared, reducing bone cement waste, and thus also reducing costs.

Another object of the invention consists in being able to control the precise and accurate amount of antibiotic drugs, which will be released locally in the patient, to be added to the bone cement mixture, during its preparation.

A further object of the invention consists in providing a device for bone cement application that is highly reliable and safe to use.

Another object of the invention consists in providing a device for bone cement application that is easy to produce and cost competitive.

This aim and these other objects, which will become better apparent hereinafter, are achieved by a device for bone cement application, particularly for arthroprosthesis implants, characterized in that it comprises a box-like body which has at least one open portion, and at least one closing element which can be engaged with said open portion of said box-like body, said boxlike body and said at least one closing element being able to contain a prosthesis component, said box-like body and said at least one closing element defining a gap, said gap adjoining at least one surface of said prosthesis component, said gap being able to be filled in with bone cement, said at least one surface of said prosthesis component being engageable with at least one bone portion of a joint.

Further features and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of a device for bone cement application, particularly for arthroprosthesis implants, illustrated by way of non-limiting example in the accompanying figures, wherein:

Figure 1 is a top perspective view of an embodiment of a device for bone cement application, according to the invention;

Figure 2 is a bottom perspective view of the device of Figure 1, according to the invention;

Figure 3 is a bottom perspective view of the device of Figure 1, in a closed configuration;

Figure 4 is a front view of the device of Figure 3;

Figure 5 is a sectional view of the device for bone cement application illustrated in Figure 4, taken along axis VV;

Figure 6 is a plan view from below of the device of Figure 3;

Figure 7 is a top plan view of the device of Figure 3;

Figure 8 is a sectional view of the device for bone cement application illustrated in Figure 7, taken along axis VIII-VIII.

With reference to the figures, the device for bone cement application, particularly for arthroprosthesis implants, is generally designated by the reference number 1 and, by way of example, it is illustrated in the accompanying figures in relation to an knee implant.

According to the invention, the device for bone cement application 1 comprises a box-like body 4, which has at least one open portion 12, and a closing element 2, which is adapted to engage with such open portion 12 of the box-like body 4. The box-like body 4 and the closing element 2 are adapted to contain a prosthetic component 3. The device, shown in Figures 3 to 8 in its closed configuration, is such that the prosthetic component 3 is inserted in the box-like body 4 and the box-like body is closed by means of the closing element 2. In this closed configuration, a gap 6 is formed between the box-like body 4, the closing element 2 and at least one surface of the prosthetic component 3. This gap 6 is adapted to be filled with bone cement, so that the bone cement extends over the surface of the prosthetic component 3, and it distributes and spreads onto it. Such surface of the prosthetic component 3 will then engage a bone portion of the joint of the patient who is receiving the prosthetic implant.

The box-like body 4 and the closing element 2 define a gap 6, which is configured to extend over the surface of the prosthesis component 3 in the closed configuration of the device 1 (i.e., when the prosthesis component 3 is inserted in the box-like body 4 and the box-like body 4 is closed by the closing element 2).

In other words, the box-like body 4 and the closing element 2 define, in the closed configuration of the device 1, a cavity. The cavity is adapted to receive a prosthetic component 3, so that, when the prosthetic component 3 is inserted into the cavity, a gap 6 is formed between the box-like body 4 and the closing element 2, wherein the gap 6 is configured to extend over the surface of the prosthetic component 3 where the bone cement is to be applied.

The device 1 can be configured to receive any prosthetic component 3. Preferably, it can be configured to receive already existing standard prosthetic components, which are also commercially available. No structural modifications o redesigns are required to existing prosthetic components in order for them to be used in the device for bone cement application, according to the invention.

The device for bone cement application 1 further comprises at least one bore 7, advantageously made in the closing element 2, which is configured to let the surplus bone cement (the bone cement in excess) coming out, when the closing element 2 is inserted into the box-like body 4 containing the prosthetic component 3. According to further embodiments of the invention, the bone cement in excess can escape from the outer perimeter of the closing element 2, or from holes made in the box-like body 4.

As clearly shown in Figure 8, the box-like body 4 is configured to receive and contain the prosthetic component 3 in a pre-determined and well-defined position, so that when the closing element 2 is inserted into the box-like body 4, it comes into contact with the prosthetic component 3 and it cannot travel further, thus forming the desired gap 6.

Advantageously, the insertion of the closing element 2 can be stopped at the right position by other types of locks or stopping mechanisms, made for example in the box-like body 4 itself.

The device for bone cement application 1 also comprises an extraction key 5 equipped with dedicated pins 8 adapted to slide within corresponding holes 9 in the box-like body 4, in order to facilitate the extraction of the prosthetic component 3 from the box-like body 4. Such extraction key 5 may be advantageously equipped with a handle 10 for its easier use.

The closing element 2 may comprise a gripping element 11 , adapted to handle the closing element 2, for its insertion and its removal from the box -like body 4.

In the embodiment of the device for bone cement application 1 illustrated in the accompanying figures, the gap 6 has a substantially constant thickness throughout the surface of the prosthetic component 3 which receives the bone cement. In this way, it is possible to determine a priori, according to geometric calculations, the amount of bone cement required to fill the gap 6, in terms of volume.

Differently, this gap 6 can have a greater thickness in correspondence with the portions of the prosthetic component 3 which will engage with cancellous bone portions of the joint, in order to ensure a sufficient penetration of the bone cement into the bone itself. By contrast, the gap 6 can have smaller thicknesses towards the extremities, or towards the perimetral portions of the prosthetic component, in order to prevent, during implantation, the bone cement in excess from pouring out.

Advantageously, the gap 6 has a thickness and a geometry which is known and defined a priori, and which is variable depending on the type and the model of the prosthetic component adopted, in order to optimize the distribution of bone cement on the prosthetic component, before its implantation into the joint.

The device for bone cement application 1 is advantageously made of a material which is substantially non-adherent to the bone cement, so as to facilitate the removal of the closing element 2 and of the prosthetic component 3 from the box-like body 4, thus avoiding unwanted removal of bone cement from the prosthetic component surface. Such material can be advantageously selected among materials belonging to the categories of silicones for medical use, rubber, plastic, metal, or among materials belonging to the category of metal alloys.

A device bone cement application of 1, according to the invention and according to alternative embodiments not illustrated in the accompanying figures, can advantageously be applied to arthroprostheses for different joints, such as for example hip, elbow, shoulder, spine or skull. According to the invention, arthroprostheses for different joints, but also different types and/or models of an arthroprosthesis, will result in devices for bone cement application with different designs and geometries.

In the case of hip arthroplasty, for example, the box-like body can be configured in such a way that, once closed by the closing element, the gap for the application of the bone cement is defined all around the stem of the prosthetic component which will then be inserted in the femur. The gap can be also designed so as to optimize the distribution of bone cement, for example, by presenting a variable thickness, greater towards the tip of the stem and smaller towards the base, so as to facilitate the penetration of bone cement towards the bottom of the intramedullary cavity obtained for inserting the stem of the prosthetic component.

According to an additional embodiment, the box-like body and the closing element can advantageously be linked to one another by means of a hinge element, such as, for example, a weakening line of the material that connects the box-like body and the closing element, or by means of a flexible material, which allows a relative rotation of the closing element with respect to the box-like body, so as to close the open portion of the latter, in order to include the prosthetic component and to create the gap to be filled in with the bone cement.

In a further embodiment, and particularly in the case of a hip prosthesis, where a femoral stem prosthetic component is applied, the closing element of the box-like body can be constituted by the prosthetic component itself which, when inserted into the box-like body, closes the open portion of the box-like body and defines the gap which is going to receive the desired amount of bone cement.

The device for bone cement application 1, according to the invention, can be advantageously included in a kit, which also includes the specific prosthetic component 3, wherein the box-like body 4, the closing element 2, the extraction key 5 and the prosthetic component 3 are included together in a sealed package that is sterile. The package can be opened directly by the surgeon in the sterile operating room.

In case the device for bone cement application 1 is an accessory of the prosthetic implant, and it is not offered together with the prosthetic component itself, it can be advantageously provided in a sterile or sterilizable package, and it can be disposable or reusable.

The operation of the device for bone cement application, particularly for arthroprosthesis implants, is described below.

The method for bone cement application by means of the device for bone cement application 1 , according to the invention, comprises the steps of:

-applying the bone cement, manually by means of a spatula, a pressure gun, or any other means, onto the surface of the prosthesis component 3 contained in the box-like body 4, through the open portion 12 of the box-like body 4;

-inserting the closing element 2 in the open portion 12 of the box-like body 4, so as to close the box-like body 4; the insertion of the closing element

2 causes the distribution of the bone cement inside the gap 6 and the filling of the gap 6 by the bone cement, as well as the possible pouring out of the bone cement in excess;

-removing the closing element 2 from the box-like body 4, using, for example, the gripping element 11 ;

-extracting the prosthesis component 3 from the box-like body 4, using, for example, the extraction key 5, via the handle 10; the prosthesis component

3 will then have a pre-defined layer of bone cement on the surface which is going to be engaged with the bone portion of the joint. If the prosthetic component 3 and the device for bone cement application 1 are available separately, it is necessary to introduce the prosthetic component 3 inside the box-like body 4, before performing the above steps. If the device for bone cement application 1 is provided together with the prosthetic component 3 in a kit which is sealed in a sterile condition, the prosthetic component 3 will be already advantageously contained in the box-like body 4, and the kit can be opened directly in the operating room.

The method for the application of bone cement by means of the device for bone cement application may comprise a further step of applying bone cement inside the box-like body, followed by a step of placing the prosthetic component inside the box-like body, in case the gap extends all around the surface of a part of the prosthesis, such as the stem of a hip prosthesis. The subsequent steps of applying the bone cement and inserting the closing element will result in the homogeneous and/or desired distribution of the bone cement in such gap extending around this part of the prosthesis.

Advantageously, the sliding of the closing element 2 during its insertion in the box-like body 4, can be stopped by the contact with the prosthesis itself, or, for example by suitable locks or stopping mechanisms, which can also be adjustable directly on the operative field, so that the desired gap 6 can be defined by the medical operator directly in the operating room. If bone cement is present in excess, during the insertion of the closing element 2, such cement can leak out from the holes 7 of the closing element 2.

In practice it has been found that the device for bone cement application, particularly for arthroprosthesis implants, according to the invention, fully achieves the intended aim and objects, since it allows to improve the performance of surgical operations for joint prosthesis implantation, reducing the surgical time and the risks for the patient. Another advantage of the device for bone cement application, according to the invention, consists in that it achieves a precise application of bone cement in known amounts on the desired surfaces of the prosthetic component to be implanted.

A further advantage of the device for bone cement application, according to the invention, consists in eliminating the amount of bone cement in excess, thus avoiding possible serious damages in the follow-up of the prosthetic implant.

Another advantage of the device for bone cement application, according to the invention, consists in ensuring the exact quantification of the amount of antibiotic drugs to be added to the mixture of cement, knowing exactly, a priori, the volume of cement to be used.

A further advantage of the device for bone cement application, according to the invention, particularly in the case where it is available in a kit comprising also the prosthetic component, consists in that a better sterility is achieved and in that the manual handling of the prosthetic component by the medical staff during surgery is reduced.

The device for bone cement application, according to the invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be replaced by other technically equivalent elements.

In practice, the materials employed, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements.

Claims

1. A device for bone cement application (1), particularly for arthroprosthesis implants, characterized in that it comprises a box-like body (4) which has at least one open portion (12), and at least one closing element (2) which can be engaged with said open portion (12) of said box-like body (4), said box- like body (4) and said at least one closing element (2) being able to contain a prosthesis component (3), said box-like body (4) and said at least one closing element (2) defining a gap (6), said gap (6) adjoining at least one surface of said prosthesis component (3), said gap (6) being able to be filled in with bone cement, said at least one surface of said prosthesis component (3) being engageable with at least one bone portion of a joint.

2. The device for bone cement application (1), according to claim 1, characterized in that said closing element (2) comprises at least one bore (7) for letting the surplus bone cement out.

3. The device for bone cement application (1), according to claim 1 and/or 2, characterized in that it comprises an extraction key (5) for the extraction of said prosthesis component (3) from said box-like body (4).

4. The device for bone cement application (1), according to one or more of the preceding claims, characterized in that said gap (6) has a known and preset thickness.

5. The device for bone cement application (1), according to one or more of the preceding claims, characterized in that said gap (6) has a substantially constant thickness extending over said at least one surface of said prosthesis component (3).

6. The device for bone cement application (1), according to one or more of the preceding claims, characterized in that said closing element (2) comprises a gripping element (11) for the removal of said closing element (2) from said box-like body (4).

7. The device for bone cement application (1), according to one or more of the preceding claims, characterized in that it is made of a material substantially not sticking to said bone cement.

8. The device for bone cement application (1), according to one or more of the preceding claims, characterized in that said prosthesis component (3) is a component of a hip prosthesis, or of a knee prosthesis, or of a elbow prosthesis, or of a shoulder prosthesis, or of a spine prosthesis, or of a skull prosthesis.

9. Kit of a device for bone cement application (1), according to one or more of claims 1 to 8, characterized in that it comprises said prosthesis component

(3), sealed in sterile packaging.

10. Method for bone cement application by means of a device for bone cement application (1) according to one or more of claims 1 to 8, characterized in that it comprises the steps of:

-applying said bone cement on said at least one surface of said prosthesis component (3) contained in said box-like body (4) having at least one open portion (12);

-inserting said at least one closing element (2) in said at least one open portion (12) in said box-like body (4), for closing said box-like body (4), said step of inserting said at least one closing element (2) causing the distribution of said bone cement in said gap (6) and the filling of said gap (6) by said bone cement;

-removing said at least one closing element (2) from said box-like body (4); -extracting said prosthesis component (3) from said box-like body (4); said prosthesis component (3) having said bone cement on said at least one surface to be engaged with a bone portion of a joint.