WO2015185865A1 - Instrument-guiding device for performing cutting and/or piercing operations on a bone part for the placement of an orthopaedic implant - Google Patents

Abstract

The device comprises a polymer block (1) produced by means of additive manufacturing such that inserts (2) are fully and non-removably integrated in the thickness thereof, said inserts being made from a high-hardness material and connected to slots (1b) or holes for guiding the instrument in the form of a blade or spindle. The inserts (2) define a guiding path for the instrument, preventing same from coming into contact with the constituent material

Description

 DEVICE FOR GUIDING AN INSTRUMENT TO PERFORM CUTTING AND / OR DRILLING OPERATIONS ON A BONE PART FOR

 The invention relates to the technical field of cutting and / or drilling guides for the placement of an orthopedic implant.

The invention finds an application for any type of orthopedic joint implant such as knee prostheses, shoulder prostheses and, more generally, any type of orthopedic implant requiring to be performed, at the level of the anatomical bone area to be prosthesis, cuts and / or piercings.

It is well known to a person skilled in the art to use different instruments, commonly called ancillaries for laying various orthopedic implants. For example, the instruments may consist of tibial cutting blocks, femoral cutting blocks, etc. These blocks incorporate in their thickness slots for the passage and guiding of organs such as cutting blades, which slots are properly oriented according to the bone cuts that must be made for the implant placement. In the same way, such blocks may have holes for guiding a wick, for example. Most of these instruments are made of metal.

However, in the context of realization of customized single-use instruments, or single-use instruments, it has appeared interesting to make these polymer instruments such as plastics. However, by definition, such a material does not have sufficient hardness, so that the introduction and action of the cutting and / or piercing member engaged in the arrangements of the block considered, may cause debris, which may not be acceptable in the surgical field. Moreover, phenomena of wear will appear.

In an attempt to remedy these drawbacks, a solution emerges from the teaching of US20050228393 which concerns an orthopedic cutting block. This block has at least two components, one of which is made of a polymeric material. The polymeric material constitutes the central core of the cutting block and has specific arrangements for cooperating with two metal plates shaped in section to form guides to a cutting blade, for example. This results in a certain complexity in its manufacture, requiring the assembly of several components. Such an orthopedic cutting block is not really a disposable instrument.

The object of the invention is to remedy these disadvantages in a simple, safe, effective and rational manner.

The problem to be solved by the invention is to be able to achieve, inexpensively, a tibial or other type of cutting block of the type commonly used, in polymer, advantageously using an additive manufacturing technology, by emancipating itself disadvantages related to this type of material namely a low resistance to friction with cutting tools such as blades, bits, reamers, ... To solve such a problem, it has been designed and developed an instrument guiding device for performing cutting and / or drilling operations on a portion of bone for the placement of an orthopedic implant comprising a polymer block, produced by additive manufacturing (or by addition of layers one after the other in order to achieve the volume of the final part) to integrate indeterminately into its thickness inserts, said inserts are made of a material with a high hardness and are in communication with slots or holes for guiding the instrument in the form of a blade or a wick, said inserts defining a guide path for the instrument by preventing it from being in contact with the constituent material of the block.

It follows from these characteristics that the inserts are integrated in the thickness of the polymer block and that in a way that can not be dismantled (neither voluntarily nor accidentally). The indémontable character is obtained by arrangements that are not feasible in conventional machining by removal of material but only in additive manufacturing.

To solve the problem that the blades, the locks or others are not in contact with the polymer, not only at the time of introduction but also during the cutting operation, drilling or otherwise, the inserts overflow a few tenths of millimeters, on both sides, slits. In one embodiment with the aim of reducing costs, the metal inserts are constituted by rods of round sections protruding by their generatrix in the slots. Advantageously, the rods protrude, on either side of the slot to form, in pairs, the guide path. The stems are positioned at each end of the slit considered. The rods are arranged, two by two, in the same alignment.

In another embodiment, the metal inserts are constituted by washers whose bore overflows into the holes.

The invention is described below in more detail with reference to the figures of the accompanying drawings, in which:

 - Figure 1 is a perspective view of an exemplary embodiment of a guide device according to the invention in the form of a cutting block;

 FIG. 2 is a side view of the cutting block illustrated in FIG. 1; - Figure 3 is a sectional view along the line C-C of Figure 2;

 FIG. 4 is a front view of the cutting block illustrated in FIG. 1;

- Figure 5 is a sectional view along the lines D-D of Figure 4;

 - Figure 6 is a perspective view of the guide device in the form of a drill guide;

 FIG. 7 is a partial perspective view corresponding to FIG. 6;

 - Figure 8 is a longitudinal sectional view of the cutting guide according to Figure 6.

The figures of the drawings show an example of the guiding device according to the features of the invention adapted, for example, to make tibial cuts without thereby excluding other applications in depending on the type of orthopedic implant to implant, for example, a femoral implant.

 Whatever the embodiment, the device comprises a block (1) of polymer, in particular plastic. Furthermore, this block (1) has any type of arrangement (la) to be adapted on a support intended to be fixed on a portion of the bone to be protected. In the example illustrated in Figures 1 to 5 the block (1) has slots (lb) for engaging and guiding a cutting tool, for example, in the form of a blade. The number of slots (lb) and their angular positioning depends on the type of cut to be made on the part of bone considered (tibial cut, femoral cut, ...).

According to a feature which is the basis of the invention, each of the slots (1b) is in communication with point zones made of a material of high hardness such as steel and, more generally, any material of at least equal hardness but generally greater than that of the tool considered, for example, the cutting blade in the illustrated examples. These point areas are suitably positioned to delimit a guide path for the cutting blade or the like, by avoiding him to be in contact with the constituent material of the block (1) for example, the plastic material.

Advantageously, these point areas are made, for each of the slots considered, by inserts (2), for example metal, protruding a few tenths of millimeters only, on either side, said slots (Ib). These inserts are constituted by rods of round sections, or others, for example, in the form of a pin protruding by their generatrix in the slots (lb) in a tangent or quasi-tangent way, with the aim of avoiding contact with the cutting blade with the constituent material of the block (1) at the moment of engagement of the cutting blade with its actuation.

As shown in particular, Figures 3 and 5, the rods (2) protrude, on either side of each slot (lb) to form two by two the guide path. Preferably, the rods (2) are positioned at each end of the slot considered (lb). Similarly, the rods (2) are arranged in pairs in a same alignment, (Figure 5). As indicated, the shape of the block (1) illustrated in FIGS. 1 to 5 is given as a non-limiting indication. For example, the block may constitute a drilling guide (3) (FIGS. 6 to 8).

 In this embodiment, the block (1) is made from a cylindrical body, also made of plastic. In this case, the inserts (2) may be constituted by washers whose internal diameter, after insertion of said washers in the plastic body, overflows the bore of said body (Figures 7 and 8).

Importantly, irrespective of the embodiment of the guiding device and in particular of the plastic block, the inserts (2) in the form of pins, washers or the like, are integrated in the thickness of the block (1) which is performed according to a known additive manufacturing technology. Such a technology makes it possible, if necessary, to completely integrate these inserts (2) in the thickness of the block in a way that can not be dismounted by being, moreover, completely embedded in the block made of polymer. This additive manufacturing process is well known to those skilled in the art. In the context of an application of this manufacturing method to the device according to the invention, when the printer arrives at the upper level of the cavity receiving the washer, for example, the 3D printer is stopped to allow to arrange the metal insert. The 3D printing process is then restarted until the desired shape of the block (1) is obtained. The metal insert (s) is / are, therefore, complemented in the polymer.

The advantages stand out well from the description, in particular one underlines and recalls:

 the possibility of producing polymer block blocks of global shapes identical to those of the metal cutting blocks, with integration of metal inserts, of a low cost in order to avoid any contact of the functional zones to avoid wear,

 the possibility of making these cutting blocks or other plastic blocks,

 - the possibility of making customized and / or disposable cutting blocks.

Finally, it is observed that the inserts metal or not, in the form of brushes, washers, occupy a place and a percentage by volume very small compared to all of the constituent material (polymer) of the block (1) or other, thus avoiding, to significantly increase, the weight of the block made in a light material.

Claims

R E V E N D I C A T IO N S -1- Device for guiding an instrument for performing cutting and / or drilling operations on a bone part for the placement of an orthopedic implant characterized in that it comprises a block (1) in polymer, made by additive manufacturing to integrate inserts (2) indemountably into its thickness, said inserts are made of a material of high hardness and are in communication with slots (1b) or holes for guiding the instrument in the form of a blade or a wick, said inserts (2) defining a guide path for the instrument by avoiding him to be in contact with the constituent material of the block (1). -2- Device according to claim 1, characterized in that the inserts (2) are constituted by rods protruding by their generatrix in the slots (lb). -3- Device according to claim 2, characterized in that the rods (2) protrude on either side of the slot (lb) to form, in pairs, the guide path (3). -4- Device according to claim 2, characterized in that the rods (2) are positioned at each end of the slot (Ib) considered. -5- Device according to claim 2, characterized in that the rods (2) are arranged, two by two, in a same alignment. -6- Device according to claim 1, characterized in that the inserts (2) are constituted by washers whose bore overflows into the holes. -7- Device according to any one of claims 1 to 6, characterized in that the block (1) is a tibial or femoral cutting block.