CA2063484A1 - Osteosynthesis plate and fastener with dynamic compressive restraint characteristics - Google Patents

Abstract

STAPLE AND SELF-RETENTIVE DYNAMICALLY COMPRESSED OSTEOSYNTHESIS PLATE. This osteosynthesis clip is made of thermo-elastic martensitic alloy, the transformation temperatures of which are: - martensitic transformation temperature Ms less than 10 .degree. VS; - austenitic transformation temperature As greater than 15.degree. VS ; and has two branches (2,3), intended to be forcibly inserted on either side of the focal point of the fracture of the bone to be repaired, said branches (2,3) being educated to deform and in particular to approach under the effect of the temperature above the austenitic transformation temperature As, said branches being connected by a connection base (1). This clip is characterized in that the connection base (1) or plate is educated to be in rectilinear form at a temperature below the martensitic transformation temperature Ms of the material which composes it, and in wavy form, inducing a shortening of its length, at a temperature higher than the austenitic transformation temperature As of said material.

Description

, r ~
AGRAP ~ AND PL ~ E ~ Ç ~ T ~ OSYNTHESE A COMPRESSION D ~ YNj ~ MIQU ~
SELF-RETENTIVE.

The invention relates to a new type of clip and 5 osteosynthesis plate with characteristics dynamic compression and self-retention.

By "dynamic compression" is meant the faculty gue present these staples or plates to generate a 10 compression force resulting ~ nte between the two poi ~ ts at level of which they are implanted and, more particularly on either side of a bone fracture focus seux.

Surgical staples used for fixation bones and soft tissue must have multiple essential characteristics. First, they should wind develop constant compression over time.
In addition, they must be anchored perfectly, 20 so as to avoid the attachment after the ~ lr implantation, stall generally due to movements of the culation or simply the bone on which they are implanted-. Finally, the a ~ implantation or removal mode staples and plagues should be simple, easy ~ put 25 in use, and generating a minimum of bone trauma.

To date, we know different types of staples or of plaques aimed at achieving these goals. We have for example proposed, to ensure their retention in soft bone, 30 staples, the lateral branches of which are provided with protrusions or edges, intended to prevent the removing the clip from the fabric (FR-A-2 52S 102). However less, if certainly this type of staples cancels any risk of anchoring out of the bone to be maintained, it generates no 35 dynamic compression, and furthermore the removal of the staple generates significant bone trauma.

We also proposed, notably in the document DE-A-2 703 529, to make staples out of material mar-tensitics (made of Ni-Ti or Ti-Nb type alloys), and give the branches of the agra ~ es a shape memory, 5 likely to bring their end closer together above the austenitic temperature of said material martensitic which composes it. This phenomenon of "memory of form "is due to the thermo-martensitic transformation reversible elastic. This well-known phenomenon consists 10 to give a material a defined shape that we treat at a temperature higher than the austenitic temperature that ace of mat ~ riau, then give it another form also defined, at a temperature below the martensitic temperature Ms of said material, and finally at lS repeat this operation several times depending on the nature of the alloy used, in order to give this material his final form memory. This temperature Ms is below the temperature As.

However, if certainly with this type of staples we obtain holds dynamic compression at the end staples, it turns out generaleme ~ t insufficient for the entire fracture at which is stapled, and even sometimes prohibitive because 25 this compression is asymmetrical, in fact, it brings the deepest parts of the fracture zone together and spreads the superficial part of this same zone.

The invention aims to overcome these various disadvantages.
30 customers. It aims at a staple or a plate of osteosyn-thesis likely to meet different requirements stated above, and capable of generating compression global dynamics, at the level of the fracture properly said on which is implanted ~ the clip or the pla ~ ue, and 35 further presenting qualities of self-retention.

This osteosynthesis plate is made of alloy thermoelastic martensitic age, whose temperatures are:
- martensitic transformation temperature Ms less than 10 C;
- austenitic transformation temperature As greater than 15- C, the transition from martensitic temperature to temperature austenitic ture inducing a shortening of the 10 plate length.

It is characterized in that it is educated for be in rectilinear form at a temperature below the martensiti-15 than Ms, and in corrugated form at a higher temperature.
re at the austenitic transformation temperature As The invention also relates to an osteo staple synthesis presenting two branches intended to be i ~ se-20 rees on either side of the focal point of the bone fracture to be repaired, said branches being educated to deform and in particular move closer under the effect of temperature, above the transformation temperature austenitic tion As, said branches being connected 25 by a connection base, consisting of a plate of the type previously mentioned.

In this way, when the entire staple is at a temperature greater than or equal to the temperature of 30 austenitic transformation, not just the end of staples is approaching but moreover and above all, the connection base itself shortens, inducing at the level of the fracture on which it is implanted, dynamic compression ta ~ t at the bone spon-35 gieux than at the level of the cortical bone, or at the level of the two upper and lower parts of the cortical bone when ~
the clip goes right through the bone 4 2 ~
Advantageously in practice:
- The clip is a one-piece clip;
- the branches are reported on the basis of cordage;
- only a portion of the connection base is educated;
- the portion of the reduced and educated base is section lower than the total section of the base;
- the connection plate or base present at 10 minus two through holes in the vicinity of their end, and intended to allow the fixing of said plate or base by any appropriate means, and in particular by screws;
- the free ends of the lateral branches of 15 the clip are also edged to increase their surface in the general plane containing them at a temperature rature higher than the austenitic temperature;
- one of the side branches is constituted ~ e of minus three sections, respectively a first and a 20 third sections, educated to be broadly per-pendulars ~ the connection base at a temperature lower than the martensitic temperature, the first section, contiguous to said base ~ so educated to spread-ter on the other side branch at a higher temperature 25 higher than the austenitic temperature, and the third section being educated to on the contrary approach the other side branch at a temperature above the austenitic temperature, said first and third sth sections being further connected by a second 30 section, generally parallel to the connection base;
- the free end of the third ~ ection is split longitudinally, the two zones thus defined being educated to stay parallel and in the prolet-management of said third section at a temperature 35 below the martensitic temperature, and for deviate in the plane of said section at a temperature ture higher than the austenitic temperature;

- the staple consists of two staples of the guestion, joined together in the vicinity of the middle of their connection base, these being educated either side of this joining zone, or of a 5 rated only;
- the clip has three branches, in a shape of Y, the bases for connecting said branches to the joining area, or only part of it they being ~ duced in accordance with the invention;
- the alloy of the clip is an alloy based on titanium-nickel or copper-aluminum-zinc alloy.

The manner in which the invention can be carried out in the resulting benefits will be more apparent from 15 examples of embodiments which follow, given for information dicative and not limiting in support of the appended figures in which :
- Figure 1 is a sc ~ ematic view of the clip according to the invention at a lower temperature 20 at the martensitic transformation temperature;
- Figure 2 is a view similar to that of the figure 1 at a temperature higher than the temperature austenitic transformation;
- Figure 3 is a view of an osteosyn plate 25 thesis according to the invention at a lower temperature re at the martensitic transformation temperature;
- Figure 4 is a view similar to that of the figure 3 at a temperature higher than the temperature austenitic transformation;
- Figure 5 is a view of another form of reaction stapling, at a temperature below the martensitic temperature;
- Figure 6 is a view similar to that of Figure 5, at a temperature higher than the temperature Austenitic;
- Figure 7 is a representation of another embodiment of the clip, at a lower temperature lower than martensitic temperature;

- Figure 8 is a view slmilaire to that of Figure 7, at a higher temperature ~ the temperature austenitigue;
- Figure 9 is a representation of another 5 embodiment of the clip, at a lower temperature lower than martensitic temperature;
- Figure 10 is a view similar to that of the Figure 9 ~ at a temperature higher than the temperature austenitic;
- Figure 11 is a schematic representation ~ se ~ tation another form of r ~ realization of the clip, to u ~ e tem-lower temperature ~ martensitic temperature;
- Figure 12 is a view similar to that of the figure 11, at a temperature higher than the temperature Austenitic;
- Figure 13 is a schematic representation of another embodiment of the clip, at a time temperature below the market temperature ~ sitic;
- Figure 14 is a view similar to that of Figure 13, at a temperature higher than the temperature austenitic.
An osteosynthesis clip is basically consisting of a base (1) on which are reported the two lateral branches (2,3). These side branches 25 (2,3) are smooth, or grainy, and may be slightly tapered at their free end (7,8), in order to facilitate their insertion during the implantation of the clip at the martensitic temperature, at the level of bone tissue from the fracture. In a known manner, and according to 30 particular therapeutic applications, the long branch branch ~ 2,3) may be the same or even different annuity. The branches can also be perpendicular res or inclined with respect to the connection base.
According to a fundamental characteristic of the invention 35 tion, the clip is made of a martensitiquethermo-elastic material, meeting the criteria ~ res of biocompati-bility required. Typically, this martensitigue material consists of a nickel-titanium alloy or an alloy based on aluminum copper and zinc.

7 ~ ~ 3; ~
The martensitic temperature Ms of the material is typically close to 10 C. At this temperature, the lateral branches (2,3) on the one hand and the connection base dement (1) on the other hand undergo repeated deformations 5 tees in order to induce a shape memory effect, which will be restored when crossing the threshold ~ e temperature-austenitic ture namely typically 25-C. This mem-re form can be acquired by different ele-elements, ie lateral branches and connection base 10 by giving them a particular shape at a temperature rature higher ~ the transformation temperature also tenitic As and then giving them another form and especially a straight shape at a lower temperature martensitic transformation temperature. In rehearsal 15 so many times these mechanical transformations nics, a rectilinear memory, respectively for the connection base and side branches to a temperature below the martensiti-that, and a wavy shape memory, as shown 20 tee in Figure 2 for the connection base with the side branches approximates ~ hant for a temperature above the austenitic threshold, are obtained.

In a particular embodiment, 25 the clip is one piece. However, in another form it is conceivable that the lateral branches rales (2,3) are reported, and this by all means bare, on the connection base (1).

In another form of realization, represented in FIGS. 5 and 6, the connection base is cons-consisting of three parts, namely two extreme parts (4,5) of given profile, and an intermediate part (6) of lower section, joining these two parts. Of the 35 so you can give a unique shape memory ment to this intermediate part, wavy shape memory lée, as shown in Figure 6. This wavy-tion of the intermediate section (6) can be carried out in the general plan of the connection base (1), as r, r as shown in figure 6, or in another plane, and in particular in a plane perpendicular to the general plane of said base (1). This undulation of the section in-intermediate (6) induces a shortening of the base of 5 connection (l) of the clip, and consequently dynamic compression of the fracture at this level. We can see in Figures 3, 4, 5 and 6, that the length jor 1 of the junction section (6) when it is straight, that is, at a temperature below 10 the transformation temperature goes ~ sitic Ms, se reduced to length l <l at a higher temperature at the austenitlque transformation temperature. This reduction results in reduction of total length L
of the connection base to a value L '<k, this 15 reduction with a typical value close to one millimeter three and a half (1.5 mm).

When the connection base ~ 1) reaches a certain length, it may be necessary to join 20 tighten it to the bone to be repaired. We realize this solida-with screws, which are inserted into the bone at through through orifices (9,10) formed therein Ci in the vicinity of its ends (see Figure 3 - 6).

In other words, the clip according to the invention provides a double compression effect and this both intramedullally, through lateral branches (2,3) whose ends (7,8) are approach, that at the external level ~ the very surface of 30 the bone, at the level of the cortical bone. In addition, given deformation of the ends of the lateral branches of the clip, it is self-retentive.

For its installation, we wear the set of 35 the clip at a temperature lower than the temperature martensitic transformation. At this temperature, the connection base (1) and the two lateral branches (2,3) are made rectilinear, said branches being generally perpendicular to the connection base 9 ~ r (1). We then implant the clip in the rectilinear position on either side of the focus of the fracture, and this by compaction, pre-holes having been previously made by the surgeon. Human body temperature 5 being higher than the austenitic temperature, the clip is formed and adopts a form defined by the memory of form already acquired. On the one hand, there is a shortcut of its connection base, and on the other hand a approximation of free extremities (7,8) of its branches 10 side shields (2,3), leading in addition to a double compression effect already mentioned, to a self-resetting result stapling.

So, as long as the temperature of the 15 fe remains above the austenitic temp ~ rature, the clip remains firmly implanted at the bone.
To remove the staple, simply cool the staple to a temperature below the transformation temperature martensitic, by any means whatsoever. We can 20 thus gently remove the staple, without risk of generating bone trauma.

There is shown in Figures 3 and 4, a plate osteosynthesis, of a type quite similar to the 25 connection base above. This plate, includes notably through holes (9,10), intended for allow its fixing by means of screws on the bone to be repaired.
As in the previous case, at a higher temperature at aust ~ niti ~ ue temperature, the intermediate section 30 is reduced from a length l to a length 1 ′ <1, induces-thus being at the level of the bone to repair a compression dynamic.

In a particular embodiment 35 described in Figures 7 and 8, the free end (7,8) of each side branch of the staple is educated to increase its surface in the plane each containing said ~ ranches (Figure 8), at a higher temperature higher than the austenitic temperature. This enlargement (11,12) thus makes it possible to increase the bearing surface of the say ends at the level of the cancellous bone, and so 5 to improve the dynamic compression "internal" to the bone to fix.

In another embodiment described in liai-sound with Figures 9 and 10, more particularly ~ adap-10 knee, one of the lateral branches (3) is consisting of three sections (13,14,15), each of them they being rectilinear ~ a temperature lower ~ lower ~ the martensitic transformation temperature. At such temperature, the first section (13) is slightly 15 apart by education, from the vertical, and this will their neighbor 15 degrees. However, the management of the third section (15) is generally perpendicular to the connection base (1) of the clip. They are interconnected by a second section (14), sensi-20 clearly parallel to said base (1). In addition, the third fifth section (15) has a slot at its end longitudinal t16), extending over a few millimeters, typically ten millimeters.

The first section (13) receives an education from shape memory such that at a higher temperature at the austenitic temperature, it approaches the au-be lateral branch (2), and becomes generally perpetual dicular to the connection base (1), inducing by 30 see consequently, a reconciliation of the other sections (14,15) of said branch t2).

- The third section (15) also receives an edu-cation of shape memory, and this on two levels. All 35 first, at a temperature higher than the temperature austenitic, said third section (15) approaches of the lateral branch (2), in order to induce an effect C ~
he dynamic compression, similar to that described in the previous examples. Then at such a temperature-re, the two zones (17,18) defined by the slot (16) at level of the end (8) of this section deviate 5 from each other in the plane of said section (15), in order to induce a retention effect at this level.

We can also provide, for this form of reaction lization, to provide through holes (not shown 10 sent ~ s) on the one hand on the connection base (1), and on the other hand on the second section (14) of the branch lateral, to allow greater fixation of the staple on its location.

In another form of realization more particularly rely described in Figures 11 and 12, the clip has the shaped like an X, and actually consists of two staples of a type previously described, joined together, for example by welding in the vicinity of the middle (19) of 20 their connection base. In this particular case, the-said connection bases (1) are edged to take dre a wavy shape at a temperature above the austenitic transformation temperature As of the material who composes them. More specifically, and in a ~ elm 25 of advantageous embodiment, said connection bases each have two intermediate parts (6) of lower section, positioned on either side of the joining area of the two clips. In this way, the resulting clip is particularly suitable 30 to reduction of complex fracture.

Similarly, the embodiment shown in Figures 13 and 14 relates to a staple complex, in the form of a Y. The three 35 branches (20) of the Y are joined together by example by welding. However, it is conceivable that this particular morphology is obtained by folding ~ ,,! J, ~

a simple staple, the two original ends of which are educated to curl inward at a temperature higher than the transformation temperature austenitic material, as for the previous staples 5 as described, and of which the fold zone (21), constitutes killing the end of the base branch (22) of the Y, is also educated to adopt this particular profile.

Furthermore, it is conceivable that each of the branches 10 has an intermediate portion of lower section (6), as previously described, or only certai-nes of them are provided with such a section, edu-quée to adopt a wavy shape ~ a temperature higher than the austenitic transformation temperature 15 as the material that composes them, so ~ induireun shortening of the branch concerned. So in depending on the particular application of the staple, can choose the most suitable morphology.

- Osteosynthesis plates and staples in accordance with the invention, prove to be perfectly suited to the roles assigned to them, and in particular, to generate a double ble dynamic compression effect at fracture level bone res.

Claims (14)

1 / Osteosynthesis plate made of an alloy thermoelastic martensitic, whose temperatures transformation are:
- martensitic transformation temperature Ms less than 10 ° C;
- austenitic transformation temperature As higher than 15 ° C;
the transition from martensitic temperature to temperature austenitic ture inducing a shortening of the plate length, characterized in that she is educated to present herself in rectilinear form at a temperature below the martensitic transformation temperature Ms of the material riau which composes it, and in wavy form 'at a temperature-ture higher than the austerity transformation temperature nitic As of said material. 2 / osteosynthesis plate according to claim 1, characterized in that it comprises in the vicinity of each cune of its ends a through hole (9,10), des-tiné to allow the joining of the plate by means screws in the bone to be repaired. 3 / Osteosynthesis plate according to one of the claims 1 and 2, characterized in that only one portion (6) of said plate is educated. 4 / osteosynthesis plate according to claim 3, characterized in that the educated portion (6) of the plate that is of section smaller than the total section of said plate. 5 / Osteosynthesis clip with two branches (2,3), intended to be inserted on either side of the focus of the bone fracture to be repaired, said branches (2,3) being educated to deform and in particular to bring together under the effect of temperature, above the austenitic transformation temperature As, the-said branches being connected by a connection base (1), characterized in that said base consists by a plate according to one of claims 1 to 4. 6 / Osteosynthesis clip according to claim 5, characterized in that it is in one piece. 7 / osteosynthesis clip according to claim 5, characterized in that the branches (2,3) are brought together tees on the connection base (1). 8 / Osteosynthesis clip according to one of the claims tions 5 to 7, characterized in that the free ends (7,8) lateral branches (2,3) of the clip are also educated to increase their surface in the plane general containing them at a temperature above the austenitic temperature. 9 / Osteosynthesis clip according to one of the claims tions 5 to 7, characterized in that one of the branches lateral (3) consists of at least three sections, respectively :
- a first section (13), adjacent to the base of connection (1), educated to move away from the other branch lateral che (2) at a temperature lower than the martensitic erasure, and to get closer to this so-called lateral branch (2) at a temperature higher than the austenitic temperature, - a third section (15), educated so that its direction be generally perpendicular to the base of connection (1) at a temperature below the time martensitic temperature, and to move away from the other lateral branch (2) at a temperature higher than the austenitic temperature, said first (13) and third section (15) being further connected by a second section (14), globally balement parallel to the connection base (1). 10 / Osteosynthesis clip according to claim 9, characterized in that the free end (8) of the third section (15) is split (16) longitudinally, the two zones (17,18) thus defined being educated for remain parallel and in the extension of said third sth section (15) at a temperature below the time martensitic temperature, and to deviate in the plane of said section at a temperature higher than the temperature austenitic ture. 11 / Osteosynthesis clip according to one of the claims cations 5 to 8, characterized in that it consists of two staples according to claim 5, secured between them near the middle (19) of their base connection (1), to take the form of an X. 12 / Osteosynthesis clip according to claim 11, characterized in that on either side of the area connection (19), the connection bases for two staples have an intermediate portion of reduced section (6), educated to adopt a wavy shape at a temperature above the temperature of austenitic transformation of the material that composes them. 13 / Osteosynthesis clip according to claim 11, characterized in that only one of the portions of the connection bases (1) has an intermediate portion diary of reduced section (6), educated to adopt a wavy shape at a temperature higher than the temperature austenitic transformation of the material which compound. 14 / Osteosynthesis clip according to one of the res-dications 5 to 8, characterized in that it comprises three branches (20,22), and is in the form of a Y, the bases for connecting said branches to the area joining (19), or only part of it they having an intermediate section portion reduced (6), educated to adopt a wavy form to a temperature higher than the transformation temperature austenitic of the material that composes them.