AU2016231338A1

AU2016231338A1 - Cutting block made of plastic with a saw blade guide made of ceramics

Info

Publication number: AU2016231338A1
Application number: AU2016231338A
Authority: AU
Inventors: Mathias Kiem; Jens SIEGFRIED
Original assignee: Ceramtec GmbH
Current assignee: Ceramtec GmbH
Priority date: 2015-03-06
Filing date: 2016-03-01
Publication date: 2017-10-19
Also published as: WO2016142213A1; JP2018507090A; KR20170134473A; RU2017135547A; CN107427306A; TW201641083A; EP3264999A1; BR112017018928A2; DE102016203351A1

Abstract

The invention relates to a cutting block (1) consisting of a base body (2) made of plastic with slot-like recesses (3) for guiding a saw blade (4) at guide surfaces which are located opposite one another. In order to reduce the plastic abrasion and allergy risk, it is proposed according to the invention that ceramic elements (5) are arranged in the base body, which form the guide surfaces for the saw blade (4).

Description

CUTTING BLOCK MADE OF PLASTIC WITH A SAW BLADE GUIDE MADE OF

CERAMIC

The invention relates to a cutting block, consisting of a base body made of plastic with slot-like recesses for guiding a saw blade on guide surfaces that are located opposite one another.

With each knee TEP implantation a cutting block also referred to as a cutting template is secured on the femur or tibia. In the normal case the distal bone cut is made using the femoral cutting block. With another femoral cutting block, four to five additional cuts are made (anterior, posterior, obliquely anterior, obliquely posterior and possibly a cut of the femoral notch) to adjust the thighbone (femur) to the geometry of the femur implant. A cut is also made on the tibia by using a cutting block. A distal, obliquely posterior and posterior saw cut is usually made on the femur for processing the bone of a unicondylar implant. A horizontal and sagittal cut is required on the tibia. The cut slots are 1 mm to 1.5 mm high, depending on the manufacturer and the knee system.

Recent additive manufacturing methods make it possible to create patient-specific cutting blocks from various plastics. In addition, plastic parts are being used to an increasing extent as alternatives to metallic instruments in knee systems. Cutting blocks made of plastic or metal cannot adequately withstand the friction created by an oscillating saw blade. This results in abrasion of material. The resulting abrasion particles are not and/or cannot be removed adequately from the wound intraoperatively. This abrasion can in turn lead to infections and/or allergic reactions in the patient. For this reason, such abrasion should be fundamentally reduced and/or prevented. This is the case in particular when a CrCoMo-free or ceramic femur component is used in a potentially allergic or metal-sensitive patient and an implant reaction is to be avoided. EP 2 624 764 A1 discloses a cutting template consisting of a single "block" made of a ceramic, which is very expensive to manufacture for this reason.

The invention is based on the object of improving upon a cutting block according to the preamble of claim 1 as follows: a) reducing the metal abrasion in comparison with previous approaches using metal. b) reducing the plastic abrasion. c) reducing the risk of allergy and/or the allergic reactions in patients and reducing the risk of infections.

According to the present invention, this object is achieved by a cutting block according to the features of claim 1.

The risk of an allergy and/or allergic reactions in patients and the risk of infections are greatly reduced due to the fact that the cutting block consists of a base body made of plastic, having slot-like recesses for guiding a saw blade on guide surfaces that are opposite one another, and ceramic elements, which form the guide surfaces for the saw blade, are arranged in the base body, so that there is no metal abrasion and hardly any plastic abrasion is formed.

The ceramic elements can preferably be inserted, impressed, deployed, clicked in or on, slid or pushed into the base body. Any type of fastening in the base body is appropriate.

In a preferred embodiment, the ceramic elements are rods, in particular having a rectangular, round or triangular cross section, or they may be lamellae.

The base body of the cutting block may be designed in one or more parts.

In one specific embodiment, the base body is designed one part and has receiving holes, such that the ceramic elements can be inserted into the receiving holes from the outside. This is especially advantageous if the ceramic elements are rods. Such a cutting block is described further below on the basis of figures.

In one alternative specific embodiment, the base body is designed to consist of multiple submodules and receiving holes are arranged in one or more submodule(s), wherein the ceramic elements can be inserted or pushed into the receiving holes. The base body is preferably designed in two parts, i.e., consisting of two submodules. Such a cutting block is described in greater detail below on the basis of figures.

In order to ensure guidance in assembling two submodules to form a cutting block, one submodule preferably has a protruding guide pin and another submodule has a guide hole, into which the guide pin fits and is situated in the installed state of the cutting block, and receiving holes are provided in the submodules to receive the ceramic elements. The receiving holes in the two submodules are arranged in alignment with one another, so that the ceramic elements may be designed as rods and can then preferably be inserted.

In a preferred embodiment, submodules are locked together, in particular by means of clips. This means that the cutting block, which consists of a plurality of submodules, is easier to handle. However, the ceramic elements must be inserted before the parts are locked together.

In one embodiment variant, the cutting block is produced by means of additive manufacturing methods. For example, this may be done for each patient individually.

Use in medical technology, in particular in surgical procedures, to treat a bone, for example, in a knee TEP implantation, is preferred. A saw blade according to the invention for use with a cutting block according to the invention is characterized in that protruding ceramic contact elements are arranged on the saw blade, sliding along the guide surfaces in the cutting block during cutting.

The contact elements may preferably comprise a ceramic coating or round, rectangular or elongated ceramic nubs.

The ceramic elements according to the invention, also known as ceramic guide plates/rails/inserts for oscillating saw blades (metal or ceramic) as solid or modular inserts (single or multiple products) in "patient-specific cutting blocks," single use cutting blocks or cutting blocks made of plastic for unicondylar and bicondylar femur/tibia processing can reduce abrasion in comparison with the metal and plastic embodiments used in the past. The ceramic elements and/or ceramic guide plates/rails/inserts may be inserted manually (impressed, deployed, clicked in or on) during production as well as immediately before surgery in corresponding "patient-specific cutting blocks," single use cutting blocks or cutting blocks made of plastic for femur processing and/or tibia processing. Depending on the design, they can be discarded after surgery or dismantled, sterilized and reused.

The cutting block according to the invention is made of plastic with the ceramic elements inserted, wherein only the guide and/or support for the oscillating saw blade is made of ceramic, while the base body is made of plastic.

The base body can be fabricated in a patient-specific shape as a disposable article and/or by means of additive manufacturing (based on X-rays, CT or MRI data records).

The ceramic elements and/or ceramic guide plates/rails/inserts can be inserted into the base body and/or its submodules (pressed, pushed, placed, clicked on or off) during production or intraoperatively - just before the insert.

The ceramic elements or flat ceramic supports for the saw blade may be used for all femur and tibia bone cuts in unicondylar and bicondylar knee surgeries.

The invention is explained in greater detail below on the basis of figures.

Figures 1 and 2 show a cutting block 1 according to the invention, also referred to as a cutting template, which is secured on the femur or in another embodiment of the base body, it is secured on the tibia and serves as a guide for saw blade (see Figures 11 to 13). The cutting block consists of a base body 2 made of plastic. For fastening, lateral straps 11 with through-holes 13 may be provided on the base body 2, for example, so that the base body 2 and/or the cutting block 1 can be secured on the femur or tibia by means of screws through these holes. Figure 1 shows the cutting block 1 from above, i.e., the side facing away from the bone, and Figure 2 shows the cutting block from below, i.e., the side facing the bone. Two centering pins 14, which are inserted into corresponding holes in the femur or tibia before fastening, may be provided on the side facing the bone in order to center the cutting block 1. For the saw blade 4 to be guided during cutting, slot-like recesses 3 having opposing guide surfaces are arranged in the cutting block 1. Depending on the required cut, the slot-like recesses 3 are arranged in a rectangular shape or at an angle to the side of the base body 2 facing the bone. One important feature of the invention is that ceramic elements 5 (see below) are arranged in the cutting block 1, forming the guide surfaces for the saw blade 4.

In the specific embodiment illustrated in Figures 1 and 2, the base body 2 consists of two submodules 7a and 7b, which are connected to one another by clips 10.

In Figures 3 and 4 the two submodules 7a and 7b are shown in greater detail. These two submodules when assembled together form the base body 2 (see Figures 1 and 2), which in turn yields the finished cutting block 1 with the ceramic elements 5 inserted (see further below).

Flook-shaped clips 10 facing the submodule 7b, which engage in corresponding pockets 15 in the submodule 7b (see Figure 4) are mounted on the submodule 7a, so that the hook-shaped end of the clip 10 engages in an enlargement in the pocket 15 and becomes hooked there. For centering, a guide pin 8 facing the submodule 7b is arranged on the submodule 7a and engages in a guide hole 9 in the submodule 7b when the two submodules 7a, 7b are joined.

As already mentioned, ceramic elements 5, which form the guide surfaces for the saw blade 4, are arranged in the cutting block 1 and/or the base body 2. In one embodiment of the invention, these ceramic elements 5 are ceramic rods 5a with a round cross section. To be able to accommodate these rods 5a, receiving holes 6, which are arranged in alignment with one another, are provided in the two submodules 7a and 7b. Figure 4 shows the contact surface facing the submodule 7a with the receiving holes 6. Before joining the two submodules, the rods 5a are inserted into these receiving holes 6 in one of the submodules, and then the two submodules 7a, 7b are joined together and anchored by the clips 10.

The opposing guide surfaces of the slot-like recesses are formed by at least three rods 5a. Figure 4 shows two opposing receiving holes 6 as an example, so that the two guide surfaces of one slot-like recess are formed by a total of four rods. Figure 4 also shows a guide surface formed by only one rod 5a. However, the guide surface opposite this rod is formed by two rods 5a.

Figure 5 shows the two submodules 7a, 7b (see Figures 1 through 4) before being joined with the rods 5a inserted into the submodule 7b. Since all the receiving holes 6 run so they are aligned with one another, the submodules 7a, 7b can also be assembled with the inserted rods 5a.

Figure 6 shows a view of the contact surface of the submodule 7b with the rods 5a inserted. This shows well one of the two centering pins 14. The guide surfaces formed by the rods 5a can also be seen in this figure.

Figure 7 shows a rod 5a with a circular cross section, which is made of a ceramic like all the ceramic elements. Preferred ceramics include sintered ceramics, for example, aluminum oxide or aluminum nitride. Figure 7 also shows other possible cross sections for rods such as squares 5b and triangles 5c. According to the invention, ceramic lamellae may also be used as ceramic elements 5, and may have a rectangular cross section 5d or a circular cross section 5e, for example. Figure 7 shows these embodiments.

Figure 8 shows the same cutting block as that shown in Figures 1 through 6, but this one has a slightly different type of joining by means of clips 10. There are again two submodules 7a and 7b, which, when assembled, form the base body 2, which in turn yields the finished cutting block 1 when the ceramic elements 5 are inserted. In this embodiment, hook-shaped clips 10 facing the submodule 7b are mounted on the submodule 7a and engage in corresponding pockets 15 in the submodule 7b, so that the hook-shaped end of the clip 10 engages in an enlarged portion of the pocket 15, where it becomes hooked. Each clip 10 consists of two individual clips 10a and 10b.

The hook-shaped ends of the individual clips 10a, 10b are arranged with a 90° offset in relation to the hook-shaped ends of the clips 10 and thus extend at a right angle to the side of the cutting block facing the bone and/or the side of the base body 2 facing the bone. For joining the two submodules 7a, 7b, the individual clips 10a, 10b engage in corresponding pockets 15 in the submodule 7b, where the hook-shaped ends of the individual clips 10a, 10b engage in enlarged portions of the pockets 15, so that they become hooked there. Since each clip 10 consists of two individual clips 10a, 10b, the result is a secure connection of the two submodules 7a, 7b. Inadvertent release of the two submodules 7a, 7b from one another is thus virtually ruled out. This embodiment may, but need not necessarily, have a guide pin 8 (see Figure 3).

Figure 9 shows a section through a cutting block according to the invention, consisting of two submodules with the ceramic elements 5 inserted, so that the ceramic elements 5d are designed in the form of lamellae and have a rectangular cross section. This can be seen well in Figure 9. With this embodiment of the inserted ceramic elements, the number of these elements may also be varied.

Figure 10 shows a one-piece base body 2 having receiving holes 6, wherein the ceramic elements 5 are inserted into the receiving holes 6 from the outside. In this embodiment, there are not two submodules but instead there is only a single one-piece base body. This eliminates the joining of the two submodules and thus eliminates the risk that the two submodules might become detached from one another. The ceramic elements 5 are formed as lamellae in the embodiment shown here. Adapting to this, the receiving holes 6 have a rectangular cross section. The cutting block according to Figure 10 is identical to the cutting block in Figure 9 with regard to the receiving holes 6 and the ceramic elements 5.

Figures 11 through 13 shows saw blades 4 according to the invention, which may be used with the cutting blocks 1 according to the invention. As a particular advantage in comparison with known saw blades, protruding ceramic contact elements 12, which slide along on the guide surfaces in the cutting block during cutting, are provided. This minimizes abrasion due to the saw blade.

Figure 11 shows one side of a saw blade 4 on which a rectangular ceramic contact element 12 is arranged. This contact element 12 slides along the guide surfaces in the cutting block during cutting.

Figure 12 shows one side of a saw blade 4, on which two rectangular ceramic contact elements 12 are arranged. During cutting, these contact elements 12 slide along the guide surfaces in the cutting block.

Figure 13 shows one side of a saw blade 4, on which round ceramic contact elements 12, which are also referred as nubs, are arranged. These contact elements 12 slide along the guide surfaces in the cutting block during cutting.

Claims

Claims

1. A cutting block (1) consisting of a base body (2) made of plastic with slot-like recesses (3) for guiding a saw blade (4) on guide surfaces that are opposite one another, characterized in that ceramic elements (5), which form the guide surfaces for the saw blade (4), are arranged in the base body.
2. The cutting block according to claim 1, characterized in that the ceramic elements (5) can be inserted, impressed, clicked in or on, deployed or pushed into the base body (2).
3. The cutting block according to claim 1 or 2, characterized in that the ceramic elements (5) are rods (5a), in particular having a rectangular, round or triangular cross section, or lamellae (5b).
4. The cutting block according to any one of claims 1 to 3, characterized in that the base body (2) is designed in one piece and has receiving holes (6), wherein the ceramic elements (5) can be inserted from the outside into the receiving holes (6).
5. The cutting block according to any one of claims 1 to 3, characterized in that the base body (2) is designed in multiple parts consisting of submodules (7a, 7b) and receiving holes (6) are arranged in one or more submodule(s) (7a, 7b), wherein the ceramic elements (5) can be inserted or pressed into the receiving holes (6).
6. The cutting block according to claim 5, characterized in that a submodule (7a) has a protruding guide pin (8) and another submodule (7b) has a guide hole (9) which fits with the guide pin (8) and, in the installed state of the cutting block (1), the guide pin (8) is in the guide hole (9) and receiving holes (6) to receive the ceramic elements (5) are arranged in the submodules (7a, 7b).
7. The cutting block according to claim 5 or 6, characterized in that submodules (7a, 7b) are locked together, in particular by means of clips (10).
8. The cutting block according to any one of claims 1 to 7, characterized in that the cutting block (1) is produced by means of additive manufacturing methods.
9. A use of a cutting block (1) according to any one of claims 1 to 8, in medical technology, in particular in surgery for treatment of a bone.
10. The use of a cutting block according to claim 9 in a knee TEP implantation.
11. A saw blade (4) for use with a cutting block (1) according to any one of claims 1 to 8, characterized in that protruding ceramic contact elements (12) are arranged on the saw blade (4) and slide along the guide faces in the cutting block (1) during cutting.
12. The saw blade (4) according to claim 11, characterized in that the contact elements (12) comprise a ceramic coating or round, rectangular or elongated ceramic nubs.