WO2008149308A1

WO2008149308A1 - Osteosynthesis staple

Info

Publication number: WO2008149308A1
Application number: PCT/IB2008/052215
Authority: WO
Inventors: Jean-Jacques Martin
Original assignee: Small Bone Innovations International SAS
Current assignee: Small Bone Innovations International SAS
Priority date: 2007-06-05
Filing date: 2008-06-05
Publication date: 2008-12-11
Anticipated expiration: 2009-12-05
Also published as: FR2916954A1; FR2962027A1; FR2916954B1

Abstract

This staple (1)comprises a central branch(1a)and two lateral branches (1b) intended to be inserted in the two bone parts (100a, 100b) to be connected; the central branch (1a) can adopt a first shape, in which the two lateral branches (1b) are distanced from each other, and a second shape, in which the two lateral branches (1b) are brought closer to each other, and these lateral branches (1b) are substantially parallel to each other in the first shape and converge toward each other in the direction of their free ends in said second shape; According to the invention, the central branch(1a)has, in said first shape, a substantially rectilinear shape, and, in said second shape, an arched or angular position, such that the central branch (1a) forms a concave curve on the side opposite that on which the lateral branches (1b) extend, or a 'V' opening from the side opposite that on which these lateral branches (1b) extend, the curve or angle of the central branch (1a) in said second shape being such that this central branch (1a) extends, after implantation, close to the cortices of the bone parts (100a, 100b) in which this staple (1) is implanted.

Description

The present invention relates to an osteosynthesis staple made of a hyperelastic or shape memory material, in particular intended for corrective surgery of the hallux valgus. It may, however, be used for any other osteosynthesis technique for which it proves to be effective. The invention also relates to an equipment including said osteosynthesis staple and a piercing guide usable for placement of this staple.

In order to maintain two bone parts in position after an osteotomy, in particular upon corrective surgery of the hallux valgus, it is well known to use hyperelastic or shape memory staples. This type of staple comprises two lateral branches and one central branch connecting these lateral branches, each lateral branch being intended to be inserted in one of the two bone parts.

A known staple comprises, at its central branch, a clevis going, by shape memory, from an elongated shape before implantation to a contracted shape after implantation, such that the two lateral branches of the staple are brought closer to each other. These lateral branches also rotate slightly after implantation, such that their free ends converge toward each other, achieving a certain compression of the interfaces of the two bone parts generated by the osteotomy.

This staple has the disadvantage of not being perfectly applied between the bone parts after implantation and therefore is in the way of the surrounding soft tissues. Moreover, the pressure exerted by the pivoting of the lateral branches on the cortices of the two bone parts results in a tendency for the staple to push itself out. Moreover and most importantly, this staple does not perfectly maintain the two bone parts, particularly with regard to pivoting of one bone part relative to the other in the longitudinal direction, and the bone interfaces are not perfectly maintained pressing against each other.

Another known staple comprises a central, S-shaped or broken line branch, the inflections of which become more marked after implantation, by shape memory, also bringing the two lateral branches of the staple closer together.

The disadvantages of this staple are substantially the same as those of the preceding staple, with the additional drawback of a deformation of the central branch which may include a certain twisting, which can lead to defective positioning of the two bone parts relative to each other. To install either of these staples, the practitioner must perform the osteotomy, then osteosynthesis of the two bone parts, which is not easy given that the distal fragment is unstable and the piercing guide used to prepare the holes for insertion of the lateral branches of the staples must be applied on these unstable fragments. The result is that this piercing guide is very often poorly centered relative to the bone parts, which requires the practitioner and his assistant to resort to the use of either forceps or temporary fixation pins, thus creating additional steps and leading to cluttering of the operation site, and creating a risk of poor positioning of the two bone parts relative to each other.

The present invention aims to resolve all of these drawbacks. The staple to which it relates comprises, in a known manner, a central branch and two lateral branches connected to the central branch, these two lateral branches each being intended to be inserted in one of the two bone parts to be connected; the central branch is modeled such that it can adopt a first shape, in which the two lateral branches are distanced from each other, and a second shape, in which the two lateral branches are brought closer to each other, and these lateral branches are substantially parallel to each other in the first shape and converge toward each other in the direction of their free ends in said second shape.

According to the invention, the central branch has, in said first shape, a substantially rectilinear shape, and, in said second shape, an arched or angular position, such that the central branch forms a concave curve on the side opposite that on which the lateral branches extend, or a "V" opening from the side opposite that on which these lateral branches extend, the curve or angle of the central branch in said second shape being such that this central branch extends, after implantation, close to the cortices of the bone parts in which this staple is implanted.

Thanks to the aforementioned curved or angled shape of the central branch after implantation, and also thanks to the aforementioned pivoting of the lateral branches, the staple according to the invention enables compression of the zones of the bone surfaces close to this central branch, all while having a weak tendency to push itself out. Moreover, the arched or angular shape of the central branch of the staple corresponds substantially to the angulation of the two bone parts to be brought together, such that this staple protrudes slightly beyond the cortex of the bone parts and never comes into any particular conflict with the surrounding soft tissues.

Preferably, the central branch comprises two holes going through it, on either side of its median zone, each intended to receive a screw fixing the staple to the corresponding bone part.

These screws make it possible to ensure perfect fixing of the staple to the bone parts. Moreover, when the staple is of the memory shape type, the aforementioned pivoting of the lateral branches is done after implementation of the screws and enables these lateral branches to bear against the fixing screws in the direction bringing the free ends of these screws closer to each other, which makes it possible to compress the zones of the bone surfaces distanced from the central branch of the staple. The staple thus makes it possible to ensure perfect compression of the bone surfaces, which is an essential condition to carry out the osteosynthesis properly. The piercing guide which may be used to place this staple comprises, according to the invention, a first block comprising a first hole for guiding piercing and a second block comprising a second hole guiding piercing, these two blocks being able to slide in relation to each other in order to bring said holes closer together or further apart. This piercing guide thus makes it possible to pierce holes in the bone before performing the osteotomy, therefore simply and easily, in stable bone parts.

Preferably,

- the sliding means of the two blocks are such that each of the two blocks can come into contact with the other block at the level of the transverse surfaces of the interface comprised by the blocks, and

- on each block, the distance separating the hole for guiding piercing and the transverse surface of the corresponding interface is equal to the distance separating each lateral branch of the staple and the median zone of the central branch of this staple.

The piercing guide according to the invention thus makes it possible, using said transverse surfaces of the interface, to locate, on the proximal cortex, the size of the osteotomy to be carried out, and to develop, in the bone, the holes for receiving the lateral branches of the staple, at the appropriate distance relative to the bone interfaces which will result from the osteotomy. Perfect positioning of the holes for receiving the lateral branches of the staple is thus obtained regardless of the width of the osteotomy to be carried out on the proximal cortex.

In practice, the two blocks are separated from each other according to the proximal width of the osteotomy to be carried out and the piercing guide is applied against the proximal cortex; the width of the osteotomy to be carried out is them determined to the right of said transverse surfaces of the interface, then the holes for receiving the lateral branches of the staple are pierced. The piercing guide is then withdrawn and the osteotomy is carried out. After pivoting the two bone parts thus formed, the staple is placed by engagement of its lateral branches in the aforementioned reception holes, the median transverse zone of the central branch positioning itself precisely aligned with the osteotomy interfaces. The staple then assumes the second shape, achieving compression of the proximal zones of the bone interfaces by the marked curvature or marked angulation of its central branch and by pivoting its lateral branches, and achieving compression of the distal zones of the bone interfaces.

When the staple comprises fixing screws, these fixing screws are installed after implantation of the staple; the bearing of the lateral branches against the screws following pivoting of these lateral branches favors compression of the distal zones of the bone interfaces as well as maintaining the screws in the bone.

Preferably, the surfaces of the piercing guide intended to come into contact with the bone have a concave shape allowing them to adapt to the convex shape of the bone, which facilitates positioning of this guide on this bone.

The invention will be well understood, and other characteristics and advantages will appear, in reference to the annexed diagrammatic drawing, illustrating, as a non-exhaustive example, several possible embodiments of the staple to which it relates.

Figures 1 to 3 are views according to a first embodiment, from the side in a non-deformed state, in a perspective view in this non-deformed state, and from the side in a deformed state, respectively; figures 4 to 6 are views according to a second embodiment, from the side in a non-deformed state, a perspective view in this non-deformed state, and from the side in a deformed state, respectively; figures 7 and 8 are perspective views according to a third embodiment, in a first shape and second shape, respectively; figure 9 is a perspective view of a cutting block making it possible to place the staple; figure 10 is a view of this block and a metatarsal bone intended to undergo treatment of a hallux valgus; figure 11 is a view of this bone after performing an osteotomy and during placement of the staple according to figures 7 and 8, and figure 12 is a view similar to figure 11 , after permanent fixing of the bone staple.

For simplification, the parts or elements of an embodiment which are found identically or similarly in another embodiment will be identified using the same numerical references and will not be described again.

Figures 1 to 8 illustrate an osteosynthesis staple 1 , in particular intended for corrective surgery of the hallux valgus.

Correction of a hallux valgus consists, as will appear in figures 10 to 12, of performing an osteotomy 101 on a bone 100 (cf. figure 10), then carrying out an osteosynthesis of the two bone parts 100a, 100b thus generated, while maintaining these two bone parts in the angled correction position (cf. figures 11 and 12). The two bone parts 100a, 100b are maintained in this corrective position by the staple 1. Figures 1 to 3 show a staple 1 in a hyperelastic material, comprising a central branch 1 a and two lateral branches 1 b connected to the central branch 1 a, each lateral branch 1 b being intended to be inserted in one of the two bone parts 100a, 100b to be connected.

The staple 1 may be deformed between a normal state of non- deformation, shown in figures 1 an 2, and a state of elastic deformation, shown in figure 3.

In its non-deformed state, the central branch 1 a of the staple 1 forms an open "V", opening from the side opposite that on which the lateral branches 1 b extend, and the lateral branches 1 b of the staple 1 converge toward each other in the direction of their free ends. In its state of elastic deformation, the staple 1 is brought to a shape in which its central branch 1a is rectilinear or in the shape of a "V" clearly more open than in the normal, non-deformed state, such that the two lateral branches are farther away from each other than in the non-deformed state, following a direction parallel to the length of the central branch 1 a. In this same state of elastic deformation, the lateral branches 1 b of the staple 1 are substantially parallel to each other.

The staple 1 is brought to this state of elastic deformation during its implantation, with the help of a suitable instrument. Figures 4 to 6 show a staple 1 very similar to that shown in figures 1 to 3, except that the central branch 1 a, instead of forming a "V", has an arched shape with its concave curvature turned from the side opposite that on which the lateral branches 1 b extend.

Figures 7 and 8 show a staple 1 in shape memory material, in particular in a nickel-titanium alloy known as "nitinol". This staple 1 a, upon its placement, has the shape shown in figure 7, in which its central branch 1 a is rectilinear or forms a very open "V" and in which its lateral branches 1 b are parallel; the staple 1 adopts, after implantation, by shape memory, the shape shown in figure 8, in which its central branch 1 a forms a closed "V", bringing the lateral branches 1 b together, and in which its lateral branches 1 b converge toward each other in the direction of their free ends.

The staple 1 also comprises two holes 2 placed through its central branch 1 a, for placement of the screw 5 for fixing the staple 1 to the bone 100, visible in figure 12. Figure 9 shows a piercing guide 10 which may be used to place the staple 1. This guide 1 is made up of two blocks 11 , 12, connected to each other, delimiting the transverse surfaces of the interface 13 and surfaces 14 to come into contact with the bone. The block 11 comprises a hole 15 to guide piercing, this hole opening into the surface 14 of its block, and the block 12 comprises a hole 16 for guiding piercing, this hole also opening into the surface 14 of this block. On each block 11 , 12, the distance separating the hole 15, 16 and the transverse surface of the corresponding interface 13 is equal to the distance separating each lateral branch 1 b of the staple 1 and the median zone of the central branch 1 a of this staple. The two blocks 11 , 12 are connected to each other slidingly, such that the two blocks can slide relative to each other to bring the holes 15 and 16 closer together or farther apart. This sliding may be done using any suitable sliding means, in particular in the form of pads integral with one of the blocks, slidingly engaged in sliding grooves provided in the other block. These sliding means are such that each of the two blocks 11 , 12 may come into contact with the other block at said transverse interface surfaces 13.

The surfaces 14 have a concave shape allowing them to adapt themselves to the convex shape of the bone 100. Moreover, the block 11 is integral with a grip shank 17, facilitating manipulation of the guide 10.

In order to place a shape memory staple as shown in figures 7 and 8, as this placement is shown in figures 10 to 12, the two blocks 11 , 12 are distanced from each other according to the proximal width of the osteotomy 101 to be performed (a scale located on one of the blocks and mark found on the other block may be included to precisely measure the distance between the two blocks); the distance between the surfaces 13 then constitutes a mark of the width of the osteotomy 101 to be performed; the piercing guide 10 is then applied against the proximal cortex of the bone 100 and marks are made on this cortex to the right of the surfaces 13; the holes 102 for receiving the lateral branches 1 b of the staple 1 are then pierced, using the holes 15 and 16 as piercing guide (figure 10).

The guide 10 is then withdrawn and the osteotomy 101 is performed. After pivoting of the two bone parts 100a, 100b thus formed, the staple 1 is placed on the bone 100 by engaging its lateral branches 1 b in the holes 102, the median transverse zone of the central branch 1a being positioned such that they are precisely aligned with the osteotomy interfaces 103 (figure 11 ).

The fixing screws 5 are then placed, after potential piercing of pre-holes intended to receive them. The staple 1 then resumes, through shape memory, its second shape shown in figure 12, performing the compression of the proximal zones of the osteotomy interfaces 103 by marked angulation of the central branch 1 a of the staple, which brings the lateral branches 1 b closer to each other, and by pivoting these lateral branches 1 b such that they converge in the direction of their free end. This pivoting allows these lateral branches 1 b to bear against the screws 5 in the direction bringing the free ends of these screws closer to each other, which makes it possible to achieve compression of the distal zones of the osteotomy interfaces 103.

The invention thus provides an osteosynthesis staple in hyperelastic or shape memory material, in particular intended for corrective surgery of the hallux valgus, and a piercing guide for the placement of this staple, which definitively resolves the disadvantages of similar materials of the prior art.

The invention was described above in reference to embodiments provided purely as examples. It goes without saying that it is not limited to these embodiments, but that it extends to all other embodiments covered by the annexed claims.

Claims

1 - Osteosynthesis staple (1 ) made of a hyperelastic or shape memory material, in particular intended for corrective surgery of the hallux valgus, comprising a central branch (1a) and two lateral branches (1 b) connected to the central branch (1 a), these two lateral branches (1 b) each being intended to be inserted in one of the two bone parts (100a, 100b) to be connected; the central branch (1 a) is modeled such that it can adopt a first shape, in which the two lateral branches (1 b) are distanced from each other, and a second shape, in which the two lateral branches (1 b) are brought closer to each other, and these lateral branches (1 b) are substantially parallel to each other in the first shape and converge toward each other in the direction of their free ends in said second shape; characterized in that the central branch (1a) has, in said first shape, a substantially rectilinear shape, and, in said second shape, an arched or angular position, such that the central branch (1a) forms a concave curve on the side opposite that on which the lateral branches (1 b) extend, or a "V" opening from the side opposite that on which these lateral branches (1 b) extend, the curve or angle of the central branch (1a) in said second shape being such that this central branch (1a) extends, after implantation, close to the cortices of the bone parts (100a, 100b) in which this staple (1 ) is implanted.

2 - Osteosynthesis staple (1 ) according to claim 1 , characterized in that the central branch (1a) comprises two holes (2) going through it, on either side of its median zone, each intended to receive a screw (5) fixing the staple (1 ) to the corresponding bone part (100a, 100b).

3 - Equipment including the osteosynthesis staple according to anyone of claims 1 -3, characterized in that it further comprises a piercing guide (10) usable to place this osteosynthesis staple (1 ) ; this piercing guide (10) comprises a first block (11 ) comprising a first hole (15) for guiding piercing and a second block (12) comprising a second hole (16) guiding piercing, these two blocks (11 , 12) being able to slide in relation to each other in order to bring said holes (15, 16) closer together or further apart.

4 - Equipment according to claim 3, characterized in that: - the sliding means of the two blocks (11 , 12) are such that each of the two blocks can come into contact with the other block at the level of the transverse surfaces (13) of the interface comprised by the blocks (11 ,12), and

- on each block (11 ,12), the distance separating the hole (15, 16) for guiding piercing and the transverse surface (13) of the corresponding interface is equal to the distance separating each lateral branch (1 b) of the staple (1 ) and the median zone of the central branch (1a) of this staple (1 ).

5 - Equipment according to claim 3 or 4, characterized in that the surfaces (14) of the piercing guide (10) intended to come into contact with the bone (100) have a concave shape allowing them to adapt to the convex shape of the bone.

6 - Equipment according to claim 4 or 5, characterized in that a scale is located on one of the blocks and a mark is located on the other block to precisely measure the distance between the two blocks.