EP3402422A1

EP3402422A1 - Orthopaedic attachment device

Info

Publication number: EP3402422A1
Application number: EP17700802.6A
Authority: EP
Inventors: Jean-Pierre Perret; Filadelfio MARLETTA
Original assignee: Gexfix SA
Current assignee: Gexfix SA
Priority date: 2016-01-15
Filing date: 2017-01-12
Publication date: 2018-11-21
Also published as: US10864017B2; FR3046725B1; US20190110815A1; BR112018014367A2; FR3046725A1; WO2017121781A1

Abstract

The invention relates to an orthopaedic attachment device (1), which can adopt at least two positions, namely an inoperative position and a locked position and which includes two clamps (2a, 2b) that are mounted opposite one another via a resilient means and are held by a tightening rod, along a median axis, via through-holes, while each of the clamps (2a, 2b) consists of a part body which includes an outer jaw (4b) and an inner jaw (4a), connected by a joining wall (5), defining an opening intended for receiving a reinforcing bar or a pin via an insert, said opening extending towards the inside of the clamp (2a, 2b) as far as the joining wall (5) towards a passage and a hinge region, characterised in that, in the inoperative position, the outer jaw (4b) is stationary, while the inner jaw (4a) is movable towards the inside, namely towards the resilient means.

Description

ORTHOPEDIC FIXING DEVICE

The present invention relates to an orthopedic fixation device for external fixators.

An orthopedic external fixator for the reduction and elongation of bone fragments is generally composed of fixation clamps in combination of stiffening bar making the connection between fixed pins in the bone parts to be treated.

Surgical methods for the installation of an external fixator generally include the insertion of pins into the bones to be reduced or lengthened, the placement of the joints and stiffening bars, the adjustment of the length and the inclination, and finally, the locking of the various mechanical elements.

Usually a fastening and articulation device is articulated around two fastening clamps formed by an assembly of independent jaws connected by a threaded rod, as disclosed by the documents EP 0 806 185, EP 1 935 357, EP 2 465 454, US 8,277,448, US 8,523,858 and US 9,138,260. The jaws of a clamp are locked in rotation, such as by a tenon engaged in a mortise, while the holding in position and the fixing of the rods and pins is ensured by the blocking of the rod passing through the clamps.

In order to simplify these orthopedic fixation devices, one-piece clamps have been developed, such as those disclosed by documents EP 2 319 436, EP 1 627 608 and US 2007/0038217. These clamps are formed of two jaws arranged in opposition, connected by a wall, forming a hinge. A clamping rod connects two clamps arranged in opposition.

The jaws of these clamps are arranged perpendicularly to the clamping rod passing through them. The major disadvantage of these clamps is that a pin or a bar can be inserted laterally, by sliding, after fixing the clamps to the rod or frontally, by clipping, before assembling the clamps to the clamping rod. It still seems possible, when the rod is not completely locked, to insert frontal way, a bar in one of the clamps. However, when a bar is inserted in one of the clamps, it is impossible to frontally introduce another bar or a pin into the second clamp.

The free ends of the jaws end with guide zones of the elements to be introduced into the clamps. These guiding zones, formed of a rounded or outwardly directed slope, serve to guide a bar or pin before clipping, but do not limit the force to be produced to engage and insert a bar into a clamp , necessary for its spacing. The present invention thus proposes an orthopedic fixation device making it possible to overcome the aforementioned drawbacks.

Thus, the orthopedic fixation device according to the invention can take at least two positions, namely a rest position and a locking position. The orthopedic fixation device comprises two clamps mounted in opposition by means of an elastic means, and held by a clamping rod, along a median axis, by through holes, while each of the clamps consists of a body piece which comprises an outer jaw and an inner jaw, connected by a junction wall, defining an opening for receiving a stiffening bar or a pin via an insert. The opening extends inwardly from the clamp to the junction wall to a passage and a hinge zone, while in the rest position the outer jaw is fixed, while the inner jaw is movable to inside, namely towards the elastic means. In addition, in the rest position, each of the inner jaws is directed outwards, namely toward the ends of the clamping rod.

Note that in the rest position, the outer surfaces of the movable inner jaws, make an acute angle directed outwardly relative to the central axis of the clamping rod. Note that the acute angle is between 80 and 88 degrees, preferably between 82 and 87 degrees. According to one feature, the outer end of each of the jaws comprises a ramp for engaging and positioning a stiffening bar or a pin via an insert, which is provided by a surface perpendicular or substantially perpendicular to the axis median of the clamping rod.

According to one embodiment, the difference in heights between the end and the center of an opening is between 5 and 25 percent, preferably between 10 and 15 percent.

According to an additional characteristic, at the level of the passage, at least one jaw comprises a compression abutment which extends at least as far as the jaw opposite to that which carries it, more preferably each of the jaws comprises a compression abutment, the abutments compression being arranged in opposition.

Note that the outer surfaces of the inner jaws each comprise a means of assembly by shape cooperation.

It should be noted that the outer surfaces each comprise a circular groove, the circular grooves into which the elastic means engage, are arranged in opposition.

Other features and advantages of the invention will become apparent from the description which follows, with reference to the accompanying drawings which are given by way of non-limiting examples.

Figures 1 to 10 are views of the orthopedic fixation device according to one embodiment.

Figure 1 is a perspective view.

Figure 2 is a side view in the locking position.

Figure 3 is a side view in the engaged position.

Figure 4 is a side view in the rest position.

Figure 5 is a rear view. Figure 6 is a sectional view of Figure 5 according to F.

Figure 7 is a side view of a clamp.

Figure 8 is a sectional view of a distal forceps, according to F.

Figure 9 is a sectional view of a proximal clamp, according to F. Figure 10 is an upper view of a clamp.

Thus, the orthopedic fixation device (1), according to the invention, comprises, in a manner known per se, a pair of adjacent clamps (2), namely a clamp in the proximal position (2a) and a clamp in the distal position (2b). ), connected by a clamping rod (3) along a median axis (X, X '), threaded at one of its ends.

Let us add that each of the clamps is formed of a single workpiece body, which comprises two jaws (4a, 4b), namely a movable inner jaw (4a) towards the inside, towards the center of the clamping rod (3). , and a fixed outer jaw (4b). The jaws (4a, 4b) of a clamp are arranged in opposition, define an opening (7) at one of their lateral ends and are connected by a junction wall (5) to their other lateral ends. These clamps (2a, 2b) each comprise a through hole (6) in which is inserted the clamping rod (3).

Note that the opening (7) of a clamp (2) is extended by a passage (8) and a hinge zone (8 ') which extends to the junction wall (5).

The proximal position and the distal position are referenced with respect to the head of the clamping rod (3).

The inner position corresponds to a position towards the center of the clamping rod (3), while an outer position corresponds to a position towards the ends of the clamping rod (3).

According to one characteristic, the fixed outer jaw (4b) of the distal clamp (2b) comprises at its through hole (6) a complementary thread to the thread of the clamping rod (3). This tapping is preferably arranged in an insert (10) engaged, advantageously end, in a blind hole arranged in the opening hole (6) of the outer jaw (4b) of the distal clamp (2b), as illustrated in FIG. Figure 9. The clamping rod (3) is advantageously a thread at one of its ends and a clamping means, such as a bolted head (11) at its other end. The part of the clamping rod (3) located below the clamping means has a length advantageously less than or equal to the thickness of two clamps (2) for fixing, so that once the clamping rod (3) inserted completely into the two clamps (2), it does not protrude from the fastening device (1).

It is understood that the clamping rod (3) can extend beyond the clamps (2) and be held together by a bolt.

According to a further feature, each of the outer surfaces, the inner jaws (4a), comprises a form cooperating means (12), such as a striated disk, as illustrated in FIG.

Note that these outer surfaces each comprise a circular groove (13) arranged in opposition, in which is engaged an elastic means (14).

According to the illustrated embodiment, the elastic means (14) is provided by a hollow cylinder of elastic material, which has a height greater than the sum of the heights of the circular grooves (13) arranged in opposition to each of the clamps (2). According to another embodiment, the elastic means (14) is a spring.

During tightening, the elastic means (14) is compressed in the circular grooves (13), until the form-fitting assembly means (12) arranged on the outer surfaces of the clamps (2) come into operation. contact and interlock against each other, ensuring a holding in the stressed position of the clamps (2) for fixing. This clamping configuration, reduces the size of the fastening device (1), by assembling two clamps (2) for fixing against each other, without insert increasing their spacing.

The fixing device (1), according to the illustrated embodiment, in particular in Figure 2, is only two clamps (2) mounted in collaboration with a clamping rod (3).

Recall that each of the clamps (2) comprises a movable inner jaw (4a) and a fixed outer jaw (4b) which delimit an opening (7) for fixing either a stiffening bar (16) or a pin (17) via a suitable insert (18), as explained in more detail in the following description.

According to one characteristic, in the rest position, as explained in more detail in the following description, the ends of the inner jaws are directed outwards, namely that the wall formed by the inner jaw (4a) does not is not perpendicular to the median axis (X, X '), but makes an acute angle (A) with the latter, as illustrated in Figure 7. More specifically, the outer surface (40) of the movable inner jaw (4a) of each of the clamps (2), makes an acute angle (A) directed outwards, with respect to the central axis (X, X ') of the clamping rod (3). According to the preceding characteristic, the acute angle (A) is between

80 and 88 degrees, preferably between 82 and 87 degrees.

Note that the outer jaw (4b) of the proximal clamp (2a) is considered fixed, since it is blocked in displacement by the bolted head (11) of the clamping rod (3), while the outer jaw (4b) of the distal clamp (2b) is considered fixed, since it is blocked in displacement either by the cooperation of the thread of the clamping rod (3) and the insertion thread (10), or by the cooperation of the thread of the clamping rod (3) and the tapping of a bolt.

The inner jaws (4a) of each of the clamps (2) are considered as movable, when the orthopedic fixation device (1) is in the rest position, given the presence of the elastic means which allows a spacing of the clamps (2), leaving the inner jaws (4a) free movement inwardly, namely towards the center of the clamping rod (3), due to the flexibility of their respective junction wall (5). The inner jaws (4a) are adapted to snap a stiffening bar (16) or a pin (17) via an insert (18). Note that an opening (7) corresponds to the sum of half-cylinder and a pad corresponding to the dimensioning of the passage (8) between the jaws (4).

More specifically, the diameter of the opening (7), when a stiffening bar or a pin via an insert is held in a clamp (2), corresponds to the sum of the radii of the two half-cylinders plus the height of the passage (8).

Note that in the rest position, the end of the inner jaw (4a) being directed outwards, the passage (8) narrows towards the opening (7). Add that the orthopedic fixation device (1) can take three positions, namely a rest position, an engaged position and a locking position.

The position of rest corresponds to a position where the clamping rod (3) is engaged in the clamps (2), the clamping rod (3) not being locked completely, so that a gap is present between the two clamps (2), the elastic means (14) not being completely compressed, the inner jaws (4a) of each of the clamps (2) are movable. The clamps are held, their angular position relative to each other, can be adjusted, by rotation of one of the clamps relative to each other. The engaged position corresponds to a position in which each of the clamps maintains a stiffening bar (16) or a pin (17) via an insert (18). The tightening of the rod (3) is in the same position as in the rest position. A gap is always present between the clamps (2), which is of course reduced compared to that of the rest position, the movable inner jaws (4a) being more open, namely the acute angles (A), of their surfaces. outside the median axis (X, X ') being larger. The locking position corresponds to the clamping rod that is properly locked, the elastic means (14) is completely compressed, the interlocking locking means (12) are in contact and interlocked. According to an additional feature, each of the jaws (4) is extended beyond the opening (7) by an engagement ramp (15) and pre-positioning, according to the illustrated embodiment, the engagement ramps (15) are parallel or substantially parallel walls, namely perpendicular or substantially perpendicular to the median axis (X, X ').

As previously introduced, in common, the end of an opening of a fastening clip abruptly ends with a rounded or outwardly directed slope. The passage of a stiffening bar (16) or a spindle insert (18), from the outside to the inside of the opening of a clamp, is realized in one go, so abrupt, generating strong vibrations in the pin (s) and therefore in the patient's bones.

The passage in these parallel ramps of engagement (15) and prepositioning, according to the invention, of a stiffening bar (16) or a spindle insert (18) (17), causes the spacing of the jaws (4), towards a position of equilibrium, while the insertion of a stiffening bar or a spindle insert, in the opening (7) is thus achieved in two stages by progressive effort, thus generating a more controlled insertion, limiting the effort of engagement and thus limiting the resulting stresses for the patient.

In order to facilitate the insertion of a stiffening bar (16) or a spindle insert (18) into an opening (7) and thus to further limit the stresses generated, the difference in height between the center of the opening (7), namely the sum of the half-cylinders and the block corresponding to the sizing of the passage (8), and the end of the opening (7), namely between the engagement ramps (15) is between 5 and 25 percent, preferably between 10 and 20 percent, more preferably between 10 and 15 percent. By way of example, according to the embodiment illustrated in FIG. 4, the difference in height between the end and the center of the opening (7), in the locked position, is about 12 percent,

The length of an engagement ramp (15) is between one-third and one-time the radius of the opening (7), namely between one sixth and one half of the height in the center of the opening (7). ).

Let us add that the passage (8) is crossed by the clamping rod (3) and further has at least one compression stop (9) arranged on at least one of the jaws (4).

It is understood that at least one compression abutment (9) is located between the through-holes (6) and the joint wall (5), more precisely between the through-holes (6) and the hinge (8 '), level of the passage (8).

At least one compression abutment (9) is provided by a projection extending in a direction opposite to the jaw (4a, 4b) which carries it. It should be noted that at least one compression abutment (9) extends over the entire thickness of the passage (8). In other words, in the rest position and in the locking position, at least one compression abutment (9) ) connects the jaws (4) of a clamp (2) at the passage (8) connecting the opening (7) to the junction wall (5).

Note that in the engaged position, as shown in Figure 3, at least one compression stop (9) is spaced apart at the passage (8).

According to one embodiment, one of the jaws (4a, 4b) comprises a compression abutment (9) which extends to the other jaw (4a, 4b) arranged in correspondence, namely extending at least over the entire thickness of the passage (8).

According to the illustrated embodiment, two compression stops (9) are each located on one of the jaws (4) and come to rest against each other in opposition, the sum of the thicknesses of the compression stops (9) is greater than or equal to, preferably substantially equal to, the thickness of the passage (8). Thus, the transition from the engaged position to the locking position, is achieved by clamping the rod (3), which causes both the approximation and elastic deformation of at least one compression stop (9), preferably the approximation and deformation of two compression stops (9), and the bending of the joint wall (5), which causes the alignment of the inner jaws (4a) perpendicularly or substantially perpendicularly to the median axis (X , X ') and thus the approximation and locking of the outer surfaces of the inner jaws (4a), against each other, by the locking of the form-fitting assembly means (12).

Note that at least one compression abutment (9) distributes the forces exerted during clamping of the rod (3), and thus limit the stresses exerted on the junction wall (5). It should be noted that the absence of at least one compression abutment (9) would cause the junction wall (5) to break when locking the clamps (2).

Claims

An orthopedic fixation device (1), which can take at least two positions, namely a rest position and a locking position, which comprises two clamps (2a, 2b) mounted in opposition through a means resilient (14), and held by a clamping rod (3), along a median axis (X, X '), by through holes (6), while each of the clamps (2a, 2b) consists of a workpiece body which comprises an outer jaw (4b) and an inner jaw (4a), connected by a junction wall (5), defining an opening (7) for receiving a stiffening bar (16) or a spindle (17) ) via an insert (18), said opening (7) extending inwardly of the clamp (2a, 2b) to the connecting wall (5) to a passage (8) and a hinge zone (8). '), while in the rest position, the outer jaw (4b) is fixed, while the inner jaw (4a) is movable inwards, ie towards the m elastic spring (14), characterized in that in the rest position, each of the inner jaws (4a) is directed outwards, namely towards the ends of the clamping rod (3).

2. Orthopedic fixation device (1) according to claim 1, characterized in that in the rest position, the outer surfaces (40) of the movable inner jaws (4a), make an acute angle (A) directed outwards with respect to the median axis (X, X ').

3. Orthopedic fixation device (1) according to the preceding claim, characterized in that the acute angle (A) is between 80 and 88 degrees.

4. Orthopedic fixation device (1) according to claims 2 or 3, characterized in that the acute angle (A) is between 82 and 87 degrees.

5. Orthopedic fixation device (1) according to any one of the preceding claims, characterized in that the outer end of each of the jaws (4) comprises an engagement ramp (15) and positioning a bar of rigidification or pin via an insert, which is presented by a surface perpendicular or substantially perpendicular to the median axis (X, X ').

6. Orthopedic fixation device (1) according to any one of the preceding claims, characterized in that the difference in heights between the end and the center of an opening (7) is between 5 and 25 percent.

An orthopedic fixation device (1) according to any one of the preceding claims, characterized in that the difference in heights between the end and the center of an opening (7) is between 10 and 15 percent,

8. Orthopedic fixation device (1) according to any one of the preceding claims _/ characterized in that at the passage (8), at least one jaw (4a, 4b) comprises a compression stop (9) which extends at least to the jaw (4a, 4b) opposite to that which carries it.

9. Orthopedic fixation device (1) according to the preceding claim, characterized in that each of the jaws (4a, 4b) comprises a compression abutment (9), the compression abutments (9) being arranged in opposition.

10. An orthopedic fixation device (1) according to any one of the preceding claims, characterized in that the outer surfaces (40) of the inner jaws each comprise a form cooperating assembly means (12).

11. Orthopedic fixation device (1) according to any one of the preceding claims, characterized in that the outer surfaces (40) each comprise a circular groove (13), the circular grooves (13), in which is engaged the elastic means (14) are arranged in opposition.