WO2014057190A1

WO2014057190A1 - Cutting guide for osteotomy

Info

Publication number: WO2014057190A1
Application number: PCT/FR2013/052333
Authority: WO
Inventors: Guillaume Derouet; Benoît GAYRAUD
Original assignee: Neosteo
Priority date: 2012-10-09
Filing date: 2013-10-01
Publication date: 2014-04-17
Also published as: FR2996441B1; FR2996441A1; FR2996440A1

Abstract

A cutting guide (1) for carrying out an osteotomy procedure associated with an opening or closing axis, comprising; a support (11) for a guide means (12) for guiding a cutting tool intended to perform said osteotomy procedure, said support being capable of defining a cutting plane; means for positioning and/or holding said support on a bone (2), said positioning and/or holding means comprising a cradle (13) comprising means for visually marking, relative to the bone, a reference axis (B) intended to be placed in coincidence with said opening or closing axis and two ends (13A, 13B) formed respectively by a clamping means (133, 134, 14) capable of exerting pressure, at a clamping point (135), on said bone (2), and a means (131) for bearing on said bone (2) at an anchoring point (132), the axis linking said anchoring point (132) and clamping point (135) forming a clamping axis (A) transverse to said reference axis (B), characterised in that the clamping axis (A) forms an angle different to 90° with the reference axis (B).

Description

CUTTING GUIDE FOR OSTEOTOMY

The field of the invention is that of the design and manufacture of osteosynthesis equipment and, more specifically, cutting guides intended to be used during osteotomy operations.

It relates more particularly to a cutting guide for performing an osteotomy associated with an opening or closing axis, comprising:

a support of a guide means for a cutting tool for producing said osteotomy, said support being able to define a cutting plane;

means for positioning and / or maintaining said support on a bone, said positioning and / or holding means comprising a hoop comprising means for visually identifying with respect to the bone a reference axis intended to be placed in coincidence with said opening or closing axis and two ends formed respectively by a clamping means capable of exerting pressure, at a clamping point on said bone, and a support means on said bone at a point of anchoring, the axis connecting said anchoring and clamping points constituting a clamping axis transverse to said reference axis.

An osteotomy operation aims at modifying the structure of a carrier bone, for example to relieve a joint or a worn part.

Such an operation consists in partially cutting the bone (tibia, femur in particular), then rotate the two parts of the bone separated by the cut, so that the axis of the bone is straightened in a direction previously determined.

Depending on the desired straightening, the operation may be accompanied by opening or closing the bone around the cut. The osteotomy is therefore associated with an opening or closing axis around which two parts of the severed bone are pivoted.

In the case of a tibial osteotomy by opening, a surgeon inserts a wedge into the cut made to open the bone by rotating the two parts of the bone, generally at an angle of 6 to 14 °. When the desired angle is reached, it removes the wedge and can insert a bone graft (pelvis extract, in general) into the notch. He then fixes a plate to the two parts of the bone delimited by the notch, in order to freeze their spacing. The notched bone then regenerates, by natural ossification, during a period of the order of a few months during which the plate remains fixed on the patient's bone, in order to stabilize the entire bone and prevent excessive fragmentary mobility. . When fully regenerated, the bone is strong enough for the plaque to be removed from the patient's body.

A closure osteotomy is different from an opening osteotomy, in that the partial cut in the bone defines a beveled wedge, or "orange quarter" shaped, to be removed, for both parts to be removed. the bone delimiting the void left by the beveled corner are brought together, before being secured by a plate. The opening osteotomy is said to be internal because the cutting takes place on the internal side of the bone whereas the closing osteotomy is said to be external because the cutting takes place on the outer side of the bone.

When performing these types of osteotomy, the surgeon can use a cutting guide, intended to guide the cutting tool (an oscillating blade saw, for example) with which he wishes to cut the bone.

For this, a cutting guide traditionally comprises a guide means, such as pins for insertion into the bone, and a support of the guide means, such as guidewires for sliding pins.

The guide means support generally defines a cutting plane, to allow precise guidance of the cutting tool blade, as the case may be, as the tool, held by the practitioner, enters the cutting plane. 'bone.

A cutting guide according to the prior art also comprises means for positioning and / or maintaining the support of the guide means, so that the guide means is precisely set up, depending on the cutting plane. defined by its support. These positioning and / or holding means generally cause the surgeon to define and fix a position of the cutting guide on the bone, prior to the placement of the support, the integration of the guide means and finally the use of the cutting tool.

Such positioning and / or holding means may in particular be made by pins, inserted in parts of the bone directly impacted or not by cutting.

Once the cut is made, the cutting tool and the cutting guide are evacuated, to allow the opening (or closing) of the bone and the mounting of a fixing plate.

In practice, the opening (or closing) axis of the osteotomy is substantially coincidental with the distal (usually straight) edge of the cutting tool, when the latter is engaged to the maximum of its stroke in the 'bone.

The realization of this axis of opening or closure, also called pivot axis in the following text, follows from the insertion of the guide means, the penetration of the cutting tool and the shape of the latter .

More specifically, the pivot axis contains points located at the intersection with the direction of the guide means.

Traditionally, a theoretical pivot axis is defined with a cutting direction to be made in the bone, preoperatively.

The placement on the bone of a cutting guide made according to the prior art generally implies that the surgeon first inserts a pin into the bone, intended to facilitate referencing and to allow the installation of the guide. cut, trying to follow the desired cutting direction towards the theoretical pivot axis.

The correct positioning of the cutting guide, dependent on that of the initial pin, is therefore primarily related to the quality of the gesture and the experience of the surgeon. In fact, the surgeon first chooses an entry point on the surface of the bone, depending on the osteotomy plate that he plans to install afterwards. opening or closing. Then, it penetrates the pin, aiming globally at an end located on an opposite surface of the bone. When he feels he has reached the theoretical pivot axis, he stops the advance of the spindle in the bone and installs the cutting guide. For this, it can slide and turn the cutting guide relative to the spindle, seeking to align the guide means support on the theoretical pivot axis, of which only one point at best has been reached by the spindle.

Thus, the installation of a cutting guide according to the prior art is conditioned and limited by the penetration of a pin into the bone, and it leaves a large margin of error as to the production of an axis of osteotomy close to a desired theoretical pivot axis.

In addition, it does not allow to permanently view this target pivot axis, and therefore does not allow it to serve as a reference from the positioning of the cutting guide. At most, the surgeon can rely on imaging means (amplification of brightness ...) to visualize, generally in 2D, on a screen, the penetration of inserted pins, allowing him to have a summary indication ( indication that can be summarized at a single point of the pivot axis) and "a posteriori" concerning the pivot axis realized.

As a result, it is not uncommon for the surgeon to retreat several times in order to insert the guide means in a position that he deems appropriate.

The risk of error on the realization of the pivot axis is important, since the insertion of a first guide pin, and the time spent on this implementation can be consequent.

However, the positioning of a first guide pin, inserted into the bone with in particular the objective of reaching a point of the pivot axis, also conditions the positioning of any additional guide pins, inserted parallel to the first .

Thus, the risk of error is further increased, and the quality of the osteotomy can be significantly reduced. In fact, a wrongly oriented pivot axis can cause the bone to be straightened in the wrong direction, generating a flessum (inability to fully extend a limb) or recurvatum (excessive hyperextension), causing new pain for the patient.

Another major disadvantage, a pivot axis made too close to the end of the bone can weaken the latter in the pivot area, to the point of risking rupture or poor healing of the bone.

Therefore, a cutting guide according to the prior art does not make it possible satisfactorily to achieve the pivot axis around which the bone subjected to the osteotomy is intended to pivot, to open or close. To optimize the realization of the pivot axis according to which the bone is intended, after cutting, to be opened or closed.

A cutting guide equipped with means for visually marking a reference axis intended to be placed in coincidence with the opening or closing axis has been developed as illustrated in US 2010/0087824. This cutting guide is consistent with that described above in the introduction. In this cutting guide, the clamping axis (XX ') and the reference axis (ΥΥ') are orthogonal. This results in a cut according to that shown in Figure 10 which illustrates the state of the art. The hatches illustrate what is actually removed during the osteotomy with respect to the axis (ΥΥ ') of reference materializing the axis of opening / closing and therefore the axis of opening / closing desired. This result has been observed in practice and can be explained for two reasons, namely the near presence of the sciatic nerve represented here by a black circle that prevents too much penetration of the cutting tool OC and the first approach used. The uncut part, represented here by crosses, stiffens the opening and is a source of fracture.

The object of the invention is therefore to provide a cutting guide enabling the osteotomy line to be optimized in order to avoid a subsequent fracture of the bone.

Another object of the invention is to provide such a cutting guide for improving the positioning and insertion of a guide means of a cutting tool. The invention also aims to provide such a cutting guide whose installation is faster and reliable and easy to handle.

The invention also aims to provide a cutting guide compatible with the left and right knees, of any size.

The invention also relates to a cutting guide whose design allows indifferently the realization of an opening or closing osteotomy

The invention also relates to a method for performing a tibial valgation osteotomy associated with an opening or closing axis whose implementation is simplified.

These objectives, as well as others which will appear later, are achieved thanks to the invention which relates to a cutting guide for performing an osteotomy associated with an axis of opening or closing, comprising:

means for positioning and / or maintaining said support on a bone, said positioning and / or holding means comprising a hoop comprising means for visually identifying with respect to the bone a reference axis intended to be placed in coincidence with said opening or closing axis and two ends formed respectively by a clamping means capable of exerting pressure, at a clamping point on said bone, and a support means on said bone at a point of anchoring, the axis connecting said anchoring points and clamping constituting a clamping axis transverse to said reference axis, characterized in that the clamping axis forms with the reference axis an angle other than 90 °.

By installing such a cutting guide, the surgeon can locate, directly on the bone to be cut, the pivot axis relative to which it then wish to open or close the bone.

The guide means support may be installed in an orientation dependent on the position of this pivot axis, so that the guide means precisely guides the cutting tool until it reaches the pivot axis.

The risk of poor insertion of the guide means is then greatly reduced and the achievement of the pivot axis is optimized.

The positioning and / or holding means comprise a hoop comprising means for locating said reference axis and provided with two ends respectively formed by a support means and a clamping means.

The adjustment and fixing of a hoop around the bone, by means of the support and clamping means, allow to define and freeze the position of the pivot axis, while taking into account a minimum distance to be respected so that the hinge of the bone contains enough material.

The design of such a hoop, with a judicious positioning of the locating means of the reference axis, also makes it possible to make the cutting guide compatible with a large number of bones, right and left in particular, and to allow simple turning of the arch to practice on the same bone an osteotomy of opening or closing.

The positioning and / or holding means also comprise a clamping means capable of exerting pressure, at a clamping point on said bone, such that said cutting guide remains in contact with said bone at said anchor point and point of contact. Tightening.

In this way, the support means may first be positioned relative to the bone, and then its locked position by the clamping means.

The contact between the cutting guide and the bone at the anchoring points and clamping allows to create an axis between these two points, around which the cutting guide is likely to be rotatable. This rotational mobility then makes it possible to adjust the positioning of the cutting guide. Preferably, the clamping axis forms with the reference axis, anchoring point side an angle of between 65 ° and 85 °. The clamping axis forms with the reference axis, on the clamping point side an angle β between 95 ° and 115 °.

Generally, the clamping axis and reference axis are coplanar and form an arch plane.

So, it can be very easy for the surgeon to visualize the correct orientation of the pivot axis, through the correct positioning of the arch.

In particular, the pivot axis is horizontal as soon as the hoop plane itself is horizontal, which the surgeon easily achieves by pivoting the hoop tight on the bone around the axis Clamping.

This manipulation is all the easier for the surgeon, it can be located on a plane of the bone (tibial plateau, for example) to place the hoop.

Preferably, the reference axis and the straight line parallel to said reference axis and passing through the anchor point are separated from each other by a predetermined distance of between 2 mm and 12 mm, preferably close to 5 mm. .

Thus, whatever the size of the bone, the osteotomy axis is always positioned at a distance from the periphery of the bone.

Preferably, said locating means comprise a pin intended at least to come into contact with said bone and to extend in coincidence with said axis of opening or closing.

In this way, the reference axis intended to be placed in coincidence with the pivot axis can be materialized by an element both thin and rigid, whose shape naturally resembles an axis of rotation.

The pin intended at least to come into contact with said bone and to extend in coincidence with said axis of opening or closing is able to penetrate inside said bone so that said pin makes it possible to materialize the pivot axis as well. well outside than inside the bone. It is therefore easily identifiable by the surgeon, on the outside, and it can constitute a stop for stopping the guiding means, or even the cutting tool, inside. Internal tracking of the axis pivot is, of course, primarily intended for bones in which its insertion has little or no risk of interference with other organs (nerves ...).

Preferably, the visual reference pin of the reference axis is inserted inside a pin holder, such as a guide barrel or barrel or tube formed on the bow, in the extension of a through hole formed in said hoop, said spindle holder extending along the reference axis. Said spindle holder can therefore be used as visual identification means and axis of rotation of the support.

Preferably, said support has an arc shape located outside the hoop and partially matching the shape thereof.

Advantageously, said support comprises receiving means capable of positioning said guide means in the direction of said reference axis.

Thus, the guide means can be inserted very precisely into the bone, for example by sliding relative to its support, and in an orientation whose target, materialized by means such as a spindle, is destined to coincide with the pivot axis.

This characteristic of the cutting guide therefore significantly improves the positioning and insertion of the guide means.

Preferably, said guide means comprises at least two guide pins intended to penetrate said bone towards said reference axis, and said reception means comprise a plurality of orifices each adapted to receive one of said guide pins.

The cooperation between pins and orifices present in the support makes it possible to simply perform a precise and reversible movement of the guide means in its support.

The plurality of orifices also makes it possible to increase the possibilities of insertion of the guiding means, depending on the bone and the cutting tool in particular. Advantageously, said support is rotatable about said reference axis.

This characteristic induces that the positioning of the support can be adjusted, adjusted according to the type of osteotomy desired, the bone concerned and the osteosynthesis plate model to be fixed, while maintaining a correct orientation of the guide means, in the direction of the pivot axis.

In particular, the rotational mobility of the support relative to the pivot axis can be used to cut the bone in two places, without disassembly of the cutting guide, to achieve a closing osteotomy.

Preferably, the support is pivotally mounted around the spindle carrier.

This design allows mounting of the bracket in the absence of mounting pin support without having to touch the pin.

Said spindle holder can therefore be used as visual identification means and axis of rotation of the support. The longitudinal axis of said guide barrel is disposed in the arch plane passing through the clamping and reference axes and coincides with the reference axis.

Preferably, said positioning and / or holding means comprise a rod removably mounted on said hoop and perpendicular to said hoop plane.

Such a rod, in addition to its gripping function may facilitate handling, may allow the surgeon to verify that the cutting guide is correctly positioned relative to the axis of the bone.

In particular, when the arch is parallel to the tibial plateau, the rod can be found parallel and superimposed on the axis of the tibia, which is easy and quick to check for the surgeon.

Once the cutting guide is positioned on the bone, it is then interesting that the rod is removed, to release greater access for the installation of the guide means, and for the passage of the cutting tool . According to an advantageous embodiment, said support is removably mounted on said hoop.

Indeed, when positioning the arch on the bone, the presence of the support is not necessary and can even be troublesome.

It is therefore particularly interesting that the support can be installed only after positioning the arch, for the introduction of the guide means of the cutting tool.

Similarly, when the guide means is correctly installed in the bone, it is advantageous to remove the support, in order to free access for the use of the cutting tool.

Preferably, the support and the hoop are made transparent to the radiation.

Preferably, said support comprises two separable parts, a first part comprising said reception means of said guide means of the cutting tool and a second part intended to be mounted rotatably about said reference axis.

In this way, it is sufficient to separate the two parts of the support to remove the latter, after insertion of the guide means in the bone in a different direction of the pivot axis.

The invention also relates to a method for performing a tibial valgation osteotomy associated with an opening or closing axis using a cutting guide of the aforementioned type, characterized in that said method comprises at least one step of placing means for positioning and / or maintaining said support on a bone so that the reference axis is placed in coincidence with said axis of opening or closure and a step of mounting the support on the means positioning and / or maintaining rotation around the reference axis for, by simple angular displacement of the support, to vary at will the position of the cutting plane of said support. Since the cutting plane is adjustable by simple rotational movement of the support around the reference axis, it is easy for the surgeon to modify the position of the cutting plane in a non-invasive manner to take account of the anatomy of the patient. bone.

The method further comprises a step of placing in the bone the one or more guide means carried by said support and a step of making the cut using a cutting tool, such as a saw, guided by said guide means to an end position preferably formed by the visual registration means relative to the bone of the reference axis.

The cutting guide being of the type of which the positioning and / or holding means comprise a hoop comprising the means for visually identifying with respect to the bone a reference axis intended to be placed in coincidence with the axis of opening or closing, a support means on said bone at an anchor point located at a predetermined minimum distance from said reference axis, a clamping means capable of exerting pressure, at a clamping point on said bone the axis connecting said anchoring and clamping points constituting a clamping axis transverse to said reference axis, said clamping and reference axes being coplanar and forming a plane called the rollbar plane, the intersection point of the axes; clamping and reference being spaced from the anchor point by a predetermined minimum distance, the method is characterized in that it comprises, during the positioning step of the positioning and / or holding means said support on a tibia so that the reference axis is placed in coincidence with said opening or closing axis, the positioning of the hoop with the plane of the hoop extending substantially parallel to the plane of the tibial plateau and with the anchoring and clamping points positioned under the tibial plateau at a distance of between 10 and 15 mm from the plate and substantially equidistant from the anterior and posterior faces of the tibia so that the clamping axis extends substantially parallel to the axis Theoretical of the femoro-tibial joint.

The method comprises, prior to the positioning of the arch, the selection of the direction of use of the arch between a first direction of use corresponding to an opening osteotomy in which the anchoring and clamping points are respectively positionable one on the outer side, also called the fibula side, of the tibia, the other on the inner side of the tibia, and a second direction of use corresponding to a closing osteotomy in which the anchoring and clamping points are respectively positionable one on the inner side of the tibia, the other on the outer side of the tibia, the selection being made by simply reversing the arch.

Other characteristics and advantages of the invention will emerge more clearly on reading the following description of a preferred embodiment of the invention, given by way of illustrative and nonlimiting example, and the appended drawings among which:

Figure 1 is a perspective view of a cutting guide according to the invention, set up and maintained on a bone, during the installation of a locating pin of a reference axis; - Figure 2 is a perspective view of a cutting guide according to the invention, set up and maintained on a bone, after installation of a guide means support and a guide means; Figure 3 is a top view of a cutting guide according to the invention, after anchoring to a bone;

- Figure 4 is a top view of a cutting guide according to the invention after clamping on a bone;

Figure 5 is a top view of a cutting guide according to the invention, set up and maintained on a bone, after installation of a locating pin of a reference axis;

FIG. 6 is a perspective view of a cutting guide according to the invention, set up and maintained on a bone, after installation of a guide means support;

Figure 7 is a top view of a cutting guide according to the invention, set up and maintained on a bone, after installation of a guide means support and a guide means; Figure 8 is a side view of a cutting guide according to the invention, set up and maintained on a bone, after installation of a guide means support and a guide means; FIG. 9 schematically illustrates the section made on a bone in comparison with the state of the art, as represented in FIG.

Figure 10 schematically illustrates the state of the art in terms of cutting made on a bone. As indicated above, the principle of the invention is to provide a cutting guide for osteotomy, allowing visualization and optimization of the embodiment of the axis according to which the sectioned bone is to be opened or closed.

With reference to FIGS. 1 and 2, a cutting guide 1 for producing an osteotomy associated with an opening or closing axis is placed on a bone 2, in this case a tibia, in order to facilitate guidance. a cutting tool (not shown).

For this, the cutting guide 1 comprises means for positioning and holding the support 11 on the bone 2, having a bow 13, this bow being shown in a position where it surrounds the bone, 180 ° (cf figure 3).

At one end of the arch 13, a point 131 facing the surface of the bone 2 constitutes a support means on the bone at an anchor point 132.

At the other end of the arch 13, a tubular portion 133 extends along an axis aligned with the anchor point 132 and the axis of the tip 131. The tubular portion 133 accommodates a counter spindle 14, whose diameter is adjusted to slide in the tubular portion (see Figure 4).

A lever system 134, known per se, makes it possible to exert a radial pressure on the counter-spindle 14, in order to maintain its longitudinal position in the tubular part 133. This lever system is internal to the tubular part 133 of the hoop and is automatic operation. This lever system is in the form of a spring blade capable of being inserted into ridges of the counter-spindle 14 in a given angular position of the counter-spindle.

When the counter-spindle 14 slides in the tubular portion 133 until exerting a pressure on the bone 2, the latter can be clamped between a clamping point 135 and the anchor point 132. The lever system 134 makes it possible to releasing the pressure exerted, while maintaining the hoop 13 secured to the bone.

In other words, the positioning and holding means comprise a clamping means 133, 134, 14 able to exert pressure, at a clamping point 135 on the bone 2, such that the cutting guide 1 remains in contact with the anchoring point 132 and clamping point 135.

More specifically, the hoop 13 is provided with two ends 13A, 13B respectively forming a support means and a clamping means.

When the arch 13 is thus secured to the bone 2, it can pivot about the axis A connecting the anchor point 132 to the clamping point 135.

Note that, in the illustrated embodiment, this axis A is also the axis along which extend the tubular portion 133 and the tip 131.

Moreover, the arch 13 supports a pin 15 which comes into contact with the bone 2 and which extends along an axis B transverse to the axis A. It is noted that the pin 15 passes completely through the bone 2, for open on the opposite side to the side where it is introduced, but it may also not open, especially when the risk of interference with a nerve (sciatica, for example) shown in SC in Figure 9 is important.

The connection between the hoop 13 and the spindle 15 comprises a spindle holder 136, such as a tube or barrel 136 extending along the axis B and adapted to guide the pin along this axis. The diameter of the pin 15 is adjusted to slide in the tube 136 (see Figure 5).

The axis B is a reference axis of the arch 13, intended to coincide with the axis of opening or closing with respect to which the two parts of the bone resulting from the osteotomy are then intended to rotate.

The positioning and the retention of the arch on the bone 2 make it possible to freeze the position of this axis B, which then constitutes a permanent reference for the surgeon, which is particularly advantageous for guiding the cutting tool on a means of guidance inserted into the bone.

Thus, in a cutting guide according to the invention, the positioning and holding means comprise means 136, 15 of visual registration with respect to the bone, a reference axis B intended to be placed in coincidence with the opening or closing axis with which the osteotomy is associated.

In addition, according to the illustrated embodiment, these locating means of the reference axis B are included in the hoop 13 and formed by a pin 15 intended to penetrate the bone 2 in coincidence with the opening axis. or closing.

In addition, the axis connecting the anchoring points 132 and clamping 135 forms a clamping axis A, transverse to the reference axis B, the axes A and B being coplanar and forming a hoop plane. In particular, the clamping axis A forms with the reference axis B, anchoring point side 132 an angle of between 65 ° and 85 °. The clamping axis A forms with the reference axis B, on the clamping point side 135 an angle β between 95 ° and 115 °.

Note that when the hoop 13 is held on the bone 2 at the anchoring points 132 and 135, the insertion of the pin 15 in the bone prevents the rotation of the hoop about the axis A and freezes the position of the cutting guide 1 relative to the bone.

In FIG. 1, a rod 16 is mounted on the arch 13, perpendicular to the hoop. Absent in FIG. 2, in particular, this rod is indeed destined to be disassembled after fixing the arch of the cutting guide 1.

Thus, the positioning and holding means comprise a rod 16 removably mounted on the hoop 13 and perpendicular to the hoop plane.

The rod 16 allows the surgeon to have an immediate visual reference of the positioning of the arch with respect to the bone on which it puts it in place.

Indeed, in the case of an osteotomy on a tibia, for example, the surgeon seeks that the hoop 13 is in a substantially horizontal plane, parallel to that of the tibial plateau, which it reaches when the stem is substantially vertical and parallel to the axis of the tibia.

The connection between the rod 16 and the hoop 13 is symmetrical, so that the rod can extend perpendicularly to the hoop, on either side of the hoop plane. In this way, the cutting guide 1 can be used, indifferently, on a bone of a left limb and on the same bone of the right limb. In addition, this flexibility allows in some cases the surgeon is not bothered by the size of the rod and maintain optimum visibility, when adjusting the cutting guide on the bone.

According to the illustrated embodiment, concerning a tibial osteotomy, the tigel6 is located on the arch 13 in a position such that in front view, at 90 ° to the vertical plane in which the tip 131 bears on the bone, the stem projects on the diaphysis of the tibia. This arrangement further improves the visual cue available to the surgeon when installing the cutting guide.

More generally, the position of the connection between the rod 16 and the hoop 13 can be defined according to the anchoring point 132, during the design of the cutting guide, so that the rod, by projection, coincides with a medium sized bone. To further facilitate this adjustment, the rod is slidable with respect to the hoop, by a known system. In order to fix the positioning of the arch 13 on the bone, the end of the rod not connected to the arch may rest on another bone (the ankle for example, in the case of illustrated tibial osteotomy).

For this, the rod 16 is equipped with a system (known per se: telescopic ...) allowing the adjustment of its length.

The rod 16 may also include support elements on the bone (support Y for example, to adopt a relatively stable position relative to the bone) and support on the bone (pins ...). The cutting guide 1 further comprises a support 11 of a guide means 12 of the cutting tool for performing the osteotomy.

The guide means 12 comprises guide pins 120 (two in number, in FIG. 2), parallel, which penetrate into the bone 2, possibly at a mark 21 consisting of an alignment of two lines like this. will be described below.

Referring to Figures 2, 7 and 8, the support 11 has an arcuate shape outside the arch 13 and partially conforming to the shape thereof.

The support January 1 is mounted by one of its ends on the arch 13, in a pivot connection, around the tube 136.

In this way, the support 11 is rotatable around the reference axis B and the guide pins 120 which will be described below can remain oriented in the direction of the reference axis B, regardless of the rotational position. of the support. These guide pins 120 therefore point towards the reference axis B.

Thus, since the hoop 13 is positioned and maintained relative to the bone 2, the position of the support 11 and thus the guide means 12 can be adjusted without changing that of the reference axis B.

The surgeon can, easily and without risk of losing this marker, bring the guide pins 120 on the mark 21 previously identified on the bone. It can also, without having to disassemble the cutting guide, perform a second cut in the bone, such as that performed in the case of a closure osteotomy, remaining perfectly oriented towards the desired closure axis. The support 11, not shown in FIG. 1, is removably mounted on the arch 13.

This characteristic of the connection between the support 11 and the hoop 13 can be accompanied by locking in position and be performed by various means, known per se (sliding ...) and not shown.

In addition, the support 11 comprises two separable parts, a first portion 111 comprising the receiving means of the guide means 12 of the cutting tool and a second portion 112 intended to be mounted rotatably around the axis B reference. The separation between these two parts (not shown) can be achieved by unlocking and sliding relative to each other (systems known per se). It facilitates the removal of the support 11, for guiding the cutting tool.

The guide pins 120 pass through the support January 1 at the level of orifices 110 (ten in number, in the example illustrated in FIG. 8), each capable of receiving one of the guide pins, and extending along axes parallel and coplanar.

The diameter of the guide pins 120 being adjusted to be able to slide in the orifices 110, the guide means 12 is guided by the support 11 during its penetration into the bone 2.

Thus, the support 11 is able to define a cutting plane.

It should be noted that the guide means 12 may comprise more than two guide pins 120, and that the guide pins may be more or less spaced apart, provided that they are smaller than the orifices 110, which makes it possible to adapt to different types of cutting tools, including different blade sizes, and different bone sizes. The guide pins 120, regardless of their number, are intended to penetrate the bone 2 in the direction of the reference axis B.

By extension, the support 11 comprises reception means, comprising the multiple orifices 110, able to position the guide means 12 in the direction of the reference axis B.

Note that the pin 15 can then, when completely through the interior of the bone 2, constitute a stop mark for the surgeon when using the cutting tool.

In addition, in the design of the arch 13, the position of the anchor point 132, located at the end of the tip 131, is defined according to that of the tube 136, in which the pin 15 slides.

Indeed, the reference axis B and the straight line parallel to said reference axis B and passing through the anchor point 132 are spaced from each other by a predetermined distance D of between 2 mm and 12 mm, preferably adjacent to 5 mm (see Figure 7), to ensure that the bone has enough material in its part, intended to act as a hinge, located in the extension of the osteotomy, beyond the axis of opening or closing. Description of use

Figures 1 to 8 illustrate various steps relating to the use of a cutting guide according to the invention, in the particular and non-limiting case of a tibial osteotomy aperture valgization.

As indicated above, the surgeon may first identify, via a mark 21, points of the bone 2 through which he plans to penetrate the cutting tool and which form a demarcation between the two parts of the bone intended to to be discarded.

This mark 21, made prior to the implementation of the guide of cut, to identify points on the bone surface through which the cutting tool is intended to penetrate.

The surgeon can make the mark 21, for example a pencil line, using a mask (not shown) partially reproducing the plate to be fixed to the bone after opening (or closing) of the bone. This mask, applied on the epiphysis of the bone, ensures that the plate remains congruent to this part of the bone, after osteotomy and opening (or closing) of the bone.

Then, he grasps the cutting guide 1, possibly via the rod 16, and brings the tip 131 of the arch 13 in a substantially horizontal plane, in contact with the bone 2 and on a lateral face of the bone located on a side opposite the mark 21 (Figure 3).

The position of the anchor point 132 is adjusted by the surgeon:

vertically, so that the reference axis B, intended to coincide with the opening axis determined in the preoperative phase, can be placed horizontally at the corresponding height;

in the horizontal plane, so that the anchor point is substantially in the middle of the lateral face of the bone.

It should be noted that a horizontal plane means a plane parallel to the tibial plateau.

The counter spindle 14 is then brought and then tightened, by sliding in the tubular part 133, substantially in the middle of the face of the bone opposite the anchoring point 132 (FIG. 4).

Special attention is paid by the surgeon so that the clamping axis A is parallel to the general plane comprising the legs of the patient, so that the axis of opening, transverse to this plane, allows an optimal correction of the knee varum (phenomenon arched legs).

In addition, the surgeon can visually align the rod 16 on the shaft of the tibia concerned by the osteotomy, to make sure to place the axis A connecting the anchoring points 132 and clamping 135 in a horizontal plane.

At this stage, the arch is held on the bone at anchor points 132 and clamping 135, and it can pivot about the clamping axis A.

The surgeon can therefore rotate the hoop relative to the axis A, holding the rod 16, until a pin 15 placed in the tube 136 extends horizontally, in accordance with the axis opening required (Figure 1).

It should be noted that the surgeon has every interest in correctly placing the clamping axis A horizontally, if necessary by using the visual reference mark that constitutes the rod 16, since it then suffices to bring the bow 13 into a horizontal plane (which is quite simple to check visually), by rotation about the axis A, to be certain that the reference axis B also extends horizontally.

The length of the rod 16 is then adjusted, so that the arch 13 can be horizontal when the rod rests on the patient's ankle.

If necessary, the rod 16 can also be held on the bone.

Therefore, the pin 15 constituting the locating means of the reference axis B can, by a sliding movement in the tube 136 exerted by the surgeon, come into contact with the bone and extend in coincidence with the opening axis with which the osteotomy is associated (Figure 5).

The arch 13 is then perfectly positioned and held on the bone 2, thanks to the anchor point 132, the clamping point 135 and the spindle 15.

The rod 16 is removed from the hoop 13, so as not to clutter the cutting guide and facilitate the mounting of a support 11, rotatable about the axis B, on the hoop (Figure 6).

Guide pins 120 are introduced into orifices 110 of the support 11. By sliding in the orifices and rotation of the support, these guide pins are brought into contact with the surface of the bone, at the mark 21 previously made ( Figure 8).

Note that if the mark 21 can not coincide with all the guide pins 120, the surgeon tries to make the maximum coincide and places any remaining guide pins nearby on the bone, so that that they allow the realization of a cut in the bone that is compatible with the mounting of the osteosynthesis plate envisaged.

The guide pins 120 are then inserted into the bone 2, possibly until they arrive at the axis B (or, abutting on the pin 15 locating this axis B, in the case where the pin 15 penetrates the bone).

Note that the depth at which each of the guide pins 120 must be inserted to reach the axis B is perfectly controlled, given the rotational movement of the support 11 relative to the axis B.

As soon as the guide pins 120 are firmly anchored in the bone, the support 11 can be removed from the arch 13 to release access to the cutting tool (step not shown).

For this, the two parts of the support 11 are unlocked, if necessary, then separated, by a relative sliding relative to each other, along an axis which is parallel to the axis of the guide pins, either at the B axis.

The surgeon then performs the osteotomy, by means of a cutting tool that it can guide on the guide pins 120, in the direction of the pin 15 which can, again, serve as a stop mark.

Although the guide pins 120 are concentrated between the mark 21 and the pin 15, the cut made in the bone is extended, by means of the cutting tool, over the entire section of the bone between the mark and pin 15.

The bone 2 is then opened by the surgeon, and the opening is maintained by the fixation of an osteosynthesis plate.

Other embodiments, based on the principle of a cutting guide such as that just described, are of course conceivable without departing from the scope of the invention.

In particular, the guide means, support, clamping and materialization may have other shapes and designs.

Claims

1. A cutting guide (1) for performing an osteotomy associated with an opening or closing axis, comprising:

a support (11) for a guide means (12) for a cutting tool for producing said osteotomy, said support being able to define a cutting plane;

means for positioning and / or maintaining said support (11) on a bone (2), said positioning and / or holding means comprising a hoop

(13) comprising means for visually identifying with respect to the bone a reference axis (B) intended to be placed in register with said opening or closing axis and two ends (13A, 13B) formed respectively by a clamping means (133, 134, 14) capable of exerting pressure, at a clamping point (135) on said bone (2), and a support means (131) on said bone (2) at a point d anchorage (132), the axis connecting said anchoring points (132) and clamping points (135) constituting a clamping axis (A) transverse to said reference axis (B), characterized in that the clamping axis (A) forms with the reference axis (B) an angle other than 90 °.

2. cutting guide (1) according to claim 1, characterized in that the clamping axis (A) forms with the reference axis (B), anchor point side (132), an angle a between 65 ° and 85 °, preferably between 70 ° and 80 °, preferably close to 75 °.

3. cutting guide (1) according to any one of the preceding claims, characterized in that the clamping axis (A) forms with the reference axis (B), side clamping point (135), an angle β between 95 ° and 115 °.

4. cutting guide (1) according to any one of the preceding claims, characterized in that said clamping axis (A) and reference axis (B) are coplanar and form a hoop plane.

5. cutting guide (1) according to one of the preceding claims, characterized in that the reference axis (B) and the straight line parallel to said reference axis (B) and passing through the anchor point (132) are spaced from each other by a predetermined distance (D) between 2mm and 12mm, preferably close to 5 mm.

6. .guide cutting (1) according to one of the preceding claims, characterized in that said locating means comprise a pin (15) intended at least to come into contact with said bone (2) and to extend in coincidence with said opening or closing axis.

Cutting guide (1) according to Claim 6, characterized in that the pin (15) for the visual identification of the reference axis is inserted inside a spindle holder (136), such as a guiding barrel or barrel or tube formed on the arch (13), in the extension of a through bore formed in said arch (13), said spindle holder (136) extending along the reference axis ( B)

8. cutting guide (1) according to any one of the preceding claims, characterized in that said support (11) is rotatably mounted about said reference axis (B).

9. Cutting guide (1) according to claim 8 taken in combination with claim 7, characterized in that the support (11) is pivotally mounted around the spindle holder (136).

10. Cutting guide (1) according to any one of the preceding claims, characterized in that said support (11) has an arc shape located at the outside of the arch (13) and partially marrying the shape thereof.

11. Cutting guide (1) according to any one of the preceding claims, characterized in that said support (11) comprises receiving means adapted to position said guide means (12) towards said reference axis (B ).

12. Cutting guide (1) according to any one of the preceding claims, characterized in that said guide means (12) comprises at least two guide pins (120) intended to penetrate said bone (2) in the direction of said reference axis (B), and said reception means comprise a plurality of orifices (110) each adapted to receive one of said guide pins.

13. Cutting guide (1) according to claim 11, characterized in that said support (11) comprises two separable parts, a first portion (11 1) comprising said means for receiving said guide means (12) of the cutting tool and a second portion (112) adapted to be rotatably mounted about said reference axis (B).

14. Cutting guide (1) according to one of the preceding claims taken in combination with claim 4,

characterized in that said positioning and / or holding means comprise a rod (16) removably mounted on said hoop (13) and perpendicular to said hoop plane.

15. Cutting guide (1) according to any one of the preceding claims, characterized in that said support (11) is removably mounted on said hoop (13).