WO2013167962A1

WO2013167962A1 - Universal fixation device for the junction of wires, for reduction and stabilisation of fractures, by using the kirschner wire technique

Info

Publication number: WO2013167962A1
Application number: PCT/IB2013/000946
Authority: WO
Inventors: Radoslava YORDANOVA
Original assignee: Easy Easy Ltd
Priority date: 2012-05-10
Filing date: 2013-05-09
Publication date: 2013-11-14
Also published as: EP2849662A1; MA20150278A1; ITRM20120205A1

Abstract

A universal fixation device for the junction of wires, for reduction and stabilisation of fractures, by using the Kirschner wire technique, has cooperating clamping plates (4, 5) being provided with a central hole (7) and retained between a head (8) of a screw (2) passing through their central hole (7) and a nut (6). The clamping plates (4, 5) have facing faces (10, 11) provided with corresponding grooves (12, 13) in order to block wires (f), and opposite faces (17, 18). A spring (3) is inserted concentrically in the screw (2). A clamping plate has a hollow prismatic member (14) surrounding the central hole (7) and projecting from its face (10) facing the other clamping plate (5) having corresponding recesses (15) adapted to guide said hollow prismatic member (14).

Description

UNIVERSAL FIXATION DEVICE FOR THE JUNCTION OF WIRES, FOR REDUCTION AND STABILISATION OF FRACTURES, BY USING THE KIRSCHNER WIRE TECHNIQUE

Technical field

The present invention relates to a universal fixation device for the junction of wires, for reduction and stabilisation of fractures, by using the Kirschner wire technique.

More specifically, the invention is inherent in a universal fixation device, i.e. an internal, external or hybrid fixation device, for the stabilisation following a preliminary reconstruction of the fractures with the Kirschner wire technique. The invention allows the above technique to be used in the treatment of various fractures, such as epiphyseal, diaphyseal, multiple, and comminuted and simple fractures.

Background art

As is well known, the Kirschner wire technique is widely used in the treatment of fractures and consists of the insertion of wires under radioscopic control in a bone tissue. These wires having different diameters depending on the bone segment to be treated (phalanges, metacarpals, ulna, radius, humerus, femur, tibia, metatarsals), are inserted into the bone tissue through a turning movement by means of appropriate toolkits. Afterward, parts of the wires that protrude from the patient's skin are externally blocked with appropriate fixation devices.

The patent application U.S. 2006/0287652 describes an adjustable fastening device having a first and a second clamping units arranged around a central spindle. Each clamping unit has a couple of clamping plates provided with a couple of male-female elements positioned symmetrically with respect to the central spindle and designed to prevent the relative rotation of the clamping plates. The clamping plates have slots for at least two fixing components such as screws, pins or wires. The patent EP 2250968 discloses an external fixation device for the reduction and stabilisation of fractures, comprising at least a couple of perforated clamping plates, a central screw which passes through them, and a nut. In the facing faces of the clamping plates there are corresponding slots in which two or more wires can be placed. At least one spring is inserted on the central screw in order to keep the two clamping plates close to each other when the nut is partially screwed onto the central screw. In this way the wires are allowed to be snap inserted laterally by acting against the action of spring. A male element and a female element that are meshed in a manner to prevent relative rotation of the clamping plates are formed in the same facing faces of the clamping plates. These male-female elements are provided in a position offset from the central screw.

In both of the aforementioned documents the presence of male-female elements, which prevents the relative rotation of the clamping plates, hinders a spreading of the same for the lateral insertion of the Kirschner wires, especially when the housing in which they must be received is located near said at least one couple of male-female elements that is offset from the central screw.

The patent application US20120095462 discloses a clamping device for an external fixation system including a first clamp having an opening for receiving an external fixation element, the first clamp having an axle seat. A swivel element comprises an axle and a post. The axle is disposed on the axle seat of the first clamp. The post extends from the axle through a second external fixation clamp. The post is arranged to swivel relative to the axle seat. The above clamping device does not allow two fixation wires to be inserted parallel to each other in the same plane as it lacks of corresponding slots. Although said device is provided of a couple of male-female elements, such male-female elements permit a limited rotation of said two clamps in a horizontal plane, so that male-female elements can not act as longitudinal guides.

Another problem of the fixation devices of the known technique is represented by the fact that these male-female elements do not give the operator the possibility to manage the fixation device and the relevant wires to be locked with reliability and safety. This is due to the fact that the couple of male-female elements is designed above all to prevent the rotation of the clamping plates, and not to improve the handling of the clamping plates in order to achieve a final locking. This requirement is particularly required in the use of Kirschner wires.

Disclosure of invention

A main object of the present invention is to provide a universal fixation device which allows internal, external and hybrid syntheses to be made in a quick, simple and versatile way.

In particular, an object of the invention is to enable a reliable lateral insertion of the Kirschner wires in a universal fixation device in which a mutual sliding of the clamping plates in the direction of the axis of the central screw and a relative divergence of the clamping plates occur for the lateral insertion of the Kirschner wires in each of its slots.

A further object of the invention is to enable a reliable manipulation of a universal fixation device before a definitive locking thereof. To achieve this object, the Applicants have foreseen that they could resort to prismatic coupling guides normally used in the common bench vices.

Therefore the present invention provides a universal fixation device for the junction of wires, for reduction and stabilisation of fractures, by using the Kirschner wire technique, comprising at least a couple of co-operating clamping plates being provided with a central hole and retained between a head of a screw passing through their central hole and a nut, the co-operating clamping plates of each couple having facing faces provided of corresponding grooves in order to form housing means adapted to receive and block wires, and opposite faces, at least a spring being inserted concentrically in said screw so to maintain the co-operating clamping plates one near to the other when the nut is partially screwed on the screw and permit wires to be laterally snap inserted in the universal fixation device by acting against the spring, universal fixation device in which, in each couple of co-operating clamping plates, a clamping plate has a hollow coupling member surrounding said central hole and projecting from its face facing the other clamping plate having corresponding recesses adapted to guide said hollow coupling member.

Moreover, advantageously, the clamping plates are externally provided, in correspondence of each housing for the Kirschner wires, an inwardly inclined profile to facilitate the insertion of the Kirschner wires. In addition, the inclined profile may be provided with projections which serve to retain the wires within the housing after their insertion.

Moreover, the housings are in the form of grooves having a transversal cross-section reducing in their sizes downward thanks to a step-shaped side in order to provide a varying groove profile susceptible to be adapted to different diameters of Kirschner wires to be received.

Still the device according to the invention can be made of one of several biocompatible, recyclable, if any, and also cheap plastic materials allowing a drastic reduction of production costs.

The fixation device according to the present invention has the advantage of being assembled before the wires are inserted and can be managed by a single operator also with a consequent time saving.

The fixation device according to the invention permits the wires to be adjusted in their fixing tension by means of the relative sliding of the locking plans of the fixation device on the same wires during the fixing operation, and the fixation device to be blocked by acting on the fixing bolt in a reversible way.

The fixation device according to the present invention, whereas the few metal parts and the Kirschner wires are made of titanium, is also compatible with environments which have intense static magnetic fields (Magnetic Resonances).

Brief description of drawings

The present invention will now be described for illustrative but not limiting purposes in its preferred embodiments, with particular reference to the accompanying drawings, in which:

- Figure 1 shows an exploded perspective view of a first embodiment of a fixation device for the reduction of fractures according to the present invention;

- Figure 2 shows an exploded, sectioned longitudinally, perspective view of the fixation device in Figure 1;

- Figures 3 and 4 show enlarged perspective views of clamping plates of the fixation device in Figure 1;

- Figures 5 and 6 show enlarged perspective views of a variation of the clamping plates in Figure 1;

- Figure 7 shows a closed perspective view of the form of the embodiment in Figure 1;

- Figures 8 and 9 show closed perspective views of a second embodiment of a fixation device according to the present invention, as seen from two different angles;

- Figures 10 and 11 show cross-sectioned perspective views of components of the fixation device in Figures 8 and 9; and

- Figures 12 and 13 are enlarged perspective views of variations of clamping plates.

Description of embodiments

Reference is made initially to Figures 1 and 2, which show an exploded perspective view and an exploded longitudinally cross-sectioned perspective view of a fixation device 1 for the reduction of fractures according to a first embodiment of the present invention. As seen in these figures, the fixation device 1 comprises a screw 2, an elastic element in the form of a helical spring 3, a first clamping plate or lower plate 4, a second clamping plate or higher plate 5, both being perforated, and a nut 6. The terms "lower" and "higher" are used only for descriptive convenience, with reference to the drawings.

Referring in particular to Figure 2, it should be immediately evident that the couple of lower and higher clamping plates 4, 5 co-operate with each other; each of the clamping plates 4 and 5 is equipped with a central hole 7, through which the screw 2 passes. The screw 2 has a cylindrical head 8 with a hexagon socket 9. The lower clamping plate 4 has a face, indicated as 10, facing the face 11 of the higher clamping plate 5. Formed in the facing face 10 of the lower clamping plate 4 are grooves generally indicated as 12, and formed in the facing face 11 of the higher plate 5 are correspondent grooves generally indicated as 13. The grooves 12, 13 are formed like the sides of a polygon, in particular a square, in the represented embodiment. The grooves have a square cross-section reducing downward thanks to a step-shaped side.

According to the present invention, the lower clamping plate 4 has a hollow coupling member projecting from the face facing 10 that surrounds the central hole 7. This hollow coupling member is shown as a prismatic member having a square plan and being denoted as 14, but it must be understood that this is not a critical feature; other possible variations are given in the following.

The hollow coupling member 14 projects from the face 10 towards the facing face 11 of the higher clamping plate 5. The facing face 11 has recesses 15 adapted to guide the hollow prismatic body 14 in its penetration in the higher clamping plate as a result of the coupling of the lower and higher clamping plates 4, 5. The recesses 15 have substantially the same shape of the hollow prismatic member 14.

When the screw 2 is inserted in the coaxial holes 7 of the higher clamping plate 5 and lower clamping plate 4, the head 8 is in the cylindrical seat 16 that is formed on the opposite face 17 of the higher clamping plate 5, with the interposition of the spring 3 (which is not cross-sectioned in Figure 2). The spring 3 preferably has a conical shape tapered towards the head 8 of the screw 2. In this way it is possible to optimally distribute the stresses on the one hand on the screw 2, and on the other hand on the clamping plate 5.

From the opposite side, the nut 6 is inserted in a seat 18 with hexagonal cross-section formed on the opposite face 19 of the lower clamping plate 4. It is understood that this provision is particularly advantageous because it allows the fixation device to be screwed and unscrewed by simply using a hex wrench on the head 8 of the screw 2. The opposite face 19 of the lower clamping plate 4 is extended in order to accommodate, in addition to the nut 6, also the head of a hex key used for tightening. In this way, the operator has no need of touching with his/her hands the fixation device, which is connected to the wires in that moment.

When the screw 2 is screwed on the nut 6, the facing faces 10, 11 are approached to each other and the grooves 12, 13 form housing means intended to receive and lock the wires f (Figure 1). This arrangement is shown in Figure 7, which shows a closed perspective view of the first embodiment.

Referring to Figures 3 and 4, which show enlarged perspective views of the clamping plates of the fixation device in figure 1, in particular of their facing faces, the conformation of the grooves 12 and 13 is best evident. It is also shown how the facing faces are bounded towards the outside. In particular, generally indicated as 20 in the grooves 12 and 13 is a step being made in correspondence of the bottom of the grooves and acting as an abutment for wires of smaller diameter. Furthermore the grooves 12 and 13 are bounded on the outside by inclined profiles, generally indicated as 21, that allow a comfortable lateral insertion of the wires, when the screw 2 is slightly loose on the nut 6.

In Figures 5 and 6, which represent a variation of the clamping plates of the fixation device in Figure 1, the same reference numbers to indicate parts identical to those of figures 3 and 4 are used. Differently from those, the lower and higher clamping plates 40, 50 have grooves 12 and 13, respectively, which are bounded externally by teeth indicated generally as 22. The teeth 22 having a profile inclined from the outside inwards improve the wire retaining effect.

The construction of details such as the steps 20, the inclined profiles 21 and the teeth 22, is facilitated by the type of material that is preferably selected for the manufacture of clamping plates, namely a suitable biocompatible, preferably recyclable, plastic material. In comparison to clamping plates made of other materials, such as metallic materials, such a clamping plate has the advantage of having a negligible weight, and therefore a better portability. Furthermore, the manufacture is definitely cheap.

Referring to Figure 7, there is shown the fixation device according to the present invention in a closed position. In order to unlock the wires f and remove them laterally from the fixation device, the screw 2 needs only to be lightly unscrewed through its head 8.

Reference is made now to Figures 8 and 9, which show closed perspective views of a second embodiment of a fixation device according to the present invention as seen from two different angles. The fixation device comprises two couples of co-operating clamping plates, in which only end plates have cylindrical and hexagonal seats for the screw head 8 and the nut 6, respectively. The two couples of clamping plates are located opposite between the screw head 8 and the nut 6, and intermediate plates 23, 23 have opposite faces in mutual contact. If the clamping plate bearing the head of the screw is indicated as 5, it is equipped with the recesses 15 for coupling with a prismatic member carried by the co-operating intermediate plate 23. The other intermediate plate 23 has a prismatic member that fits in the recesses 15 made in a clamping plate 24 having a seat for the hexagonal nut 6, as shown in Figure 10. Schematically represented in figure 10 is a clamping plate 23 which differs from the clamping plate 4 or 40 only because it lacks of its rear part, namely the one destined to receive the hexagonal cross-section seat for the nut. As for the clamping plate 24 shown in detail in Figure 11, it differs from the clamping plate 5 as it has a hexagonal cross-section seat 18 for the nut 6 instead of the circular cross-section seat 16 for the screw head 8 of the clamping plate 4 or 40 in the first embodiment.

Referring to Figures 12 and 13, which are enlarged perspective views of variations of clamping plates, they show clamping plates 25 and 26 similar to the clamping plates 4, 40, but having different projecting members 27, 28 which, in combination with complementary recesses (not shown) formed in the facing clamping plates, constitute guides for the couple of clamping plates in the universal fixation device according to the present invention. In Figures 12 and 13, where the same reference numerals are used to indicate equal parts, an elliptical member 27 and a cylindrical member 28 respectively, are represented like projecting coupling members having complementary recesses. In order to avoid the relative rotation between the mutually coupled clamping plates, when the projecting hollow coupling member is a cylindrical member 28, there is provided in its internal or external side, the latter being shown in Figure 13, a longitudinal projection 29 intended to engage slidably with similar recessed portion in the opposite clamping plate. It is evident that the recesses of the facing clamping plates (not shown) must be complementary to the hollow coupling member, even in the case of the variations of Figures 12 and 13.

From the foregoing description the advantages should be evident that come from the characteristics of the universal fixation device according to the present invention.

In particular, the hollow coupling member, in co-operation with the complementary recess of the facing clamping plate, is a means that does not allow the reciprocal rotation of the coupled clamping plates, and especially constitutes an effective prismatic coupling, thanks to the recess acting as a guide. This coupling allows the mutual inclination for a lateral insertion of a wire while another wire is already present between the clamping plates, the already present wire not hindering such insertion.

Moreover, the co-operation between the hollow coupling member with the recess allows a relative sliding of the clamping plates until achieving an optimal position of the wires that will be made definitive by fully tightening the screw.

Corresponding grooves formed on the facing faces of the plates constitute housing means adaptable to wires of different diameter.

The outer side profile of these grooves is formed according to an inclined plane that is continuous, or discontinuous if it is made by separated teeth. The outer side profile allows the wires to be comfortably laterally inserted and retained between the clamping plates, once the screw is fully screwed on the nut against a counteracting force of the spring and of the clamping plates themselves.

It should be evident that certain embodiments and variations of the universal fixation device according to the present invention have been described, and that other modifications and variations can be provided in the scope of the appended claims.

Claims

1. A universal fixation device for the junction of wires, for reduction and stabilisation of fractures, by using the Kirschner wire technique, comprising at least a couple of co-operating clamping plates (4, 5; 40, 50; 5, 23, 23, 24; 25; 26) being provided with a central hole (7) and retained between a head (8) of a screw (2) passing through their central hole (7) and a nut (6), the cooperating clamping plates (4, 5; 40, 50; 5, 23, 23, 24; 25; 26) of each couple having facing faces (10, 11) provided with corresponding grooves (12, 13) in order to form housing means adapted to receive and block wires (f), and opposite faces (17, 18), at least a spring (3) being inserted concentrically in said screw (2) so to maintain the co-operating clamping plates (4, 5; 40, 50; 5, 23, 23, 24; 25; 26) one near to the other when the nut (6) is partially screwed on the screw (2) and permit wires (f) to be laterally snap inserted in the universal fixation device by acting against the spring (3), characterised in that, in each couple of co-operating clamping plates (4, 5; 40, 50; 5, 23, 23, 24; 25; 26), a clamping plate (4; 40; 23, 23) has a hollow coupling member (14; 27; 28) surrounding said central hole (7) and projecting from its face (10; 23, 23) facing the other clamping plate (5; 50; 5, 24) having corresponding recesses (15) adapted to guide said hollow coupling member (14; 27; 28).

2. The universal fixation device according to claim 1, characterised in that said grooves (12, 13) have a square cross-section reducing downward thanks to a step-shaped side.

3. The universal fixation device according to claims 1 and 2, characterised in that said grooves (12, 13) are externally limited by a profile (21) having an inwardly inclined plane.

4. The universal fixation device according to claim 1, characterised in that said grooves (12, 13) are externally limited by teeth (22).

5. The universal fixation device according to claim 1, characterised by comprising only a couple of co-operating clamping plates (4, 5; 40, 50), in which a first clamping plate (4; 40) has, in its opposite face (19), a hexagonal cross-section seat (18) for said nut (6), and a second clamping plate (5; 50) has, in its opposite face (17), a circular cross-section seat (16) for the head (8) of a hexagonal socket screw (2).

6. The universal fixation device according to claim 1, characterised by comprising two couples of co-operating clamping plates (5, 23, 23, 24), that are juxtaposed between the head (8) of the screw (2) and the nut (6), so that a first clamping plate (24) has, in its opposite face, a hexagonal cross-section seat (18) for said nut (6), and a fourth clamping plate (5) has, in its opposite face, a circular cross-section seat for the head (8) of a hexagonal socket screw (2), and intermediate clamping plates (23, 23) have opposite faces in mutual contact.

7. The universal fixation device according to claims 5 and 6, characterised in that said hexagonal cross-section seat (18) for said nut (6) is elongated for further receiving inside a hexagonal head of an alien key.

8. The universal fixation device according to claim 1, characterised in that the co-operating clamping plates (4, 5; 40, 50; 5, 23, 23, 24; 25; 26) are made of plastic material.

9. The universal fixation device according to claim 1, characterised in that said hollow coupling member is of a shape selected among that one of a prismatic member (14), of an elliptical member (27), and of a cylindrical member (28) provided with a longitudinal ridge (29).