MXPA00010466A - Connecting element for a monolateral external fixation system for traumatology and orthopaedics - Google Patents

Abstract

A device for external fixation of parts of broken bones, comprising a longitudinal connecting element (1) with a centre axis (7). In the direction of the centre axis, the connecting element (1) is telescopic and torsionally rigid. Jaws (2) for the fixation of bone screws can be detachably arranged on said connecting element (1). The connecting element (1) has a centre part (8) and two outer parts (16;17) that can be displaced along the centre axis (7). The connecting element (1) can be extended on both sides by means of said displaceable outer parts (16;17) and has thesame diameter lengthwise apart from a small centre piece. The interchangeable centre piece (8) and outer parts (16;17) render the connecting element (1) selectably rigid.

Description

CONNECTION ELEMENT FOR AN EXTERNAL MONOLATERAL FIXING SYSTEM FOR TRAUMATOLOGY AND ORTHOPEDICS Description of the invention The invention relates to a device for externally fixing fractured bone parts according to the preamble of claim 1. By the state of the art it is known to EP 0 011 258 to the ORTHOFIX a device for externally fixing the parts of a fractured bone. This known invention comprises an elongated central body constituted by two parts that can be displaced parallel to its longitudinal axis with respect to each other, each part of the central body being provided with a trapping device for nails or bone screws applicable to a part of a body. bone, and a pressure and traction device that attacks both parts of the central body. The clamping devices are housed by spherical joints at the ends of the movable parts of the central body, which allows a tilting of the trapping devices and of the nails or screws applicable to the bone parts with three degrees of freedom. Another device for the external fixation of bones by pins known from the state of the art is disclosed in US 5,160,335 WAGENKNECHT.

This known invention comprises a fixation rod which can also be telescopic with clamping elements for clamping the bone pins, connection parts with curved seating surfaces for the clamping elements, and clamps for clamping the clamping elements with the connecting parts on the fixing rod. The connection parts are configured in such a way that the clamping elements can swing with respect to the clamps with three degrees of freedom. Both devices known from the state of the art have the disadvantage that, although it is true that the fixing rod is telescopic, however the movement of the telescopic parts is produced by a pressure and traction device mounted externally to the fixing rod or by means of a fixing screw placed on the fixing rod. Furthermore, in both of the known devices, the fixing rod can only be extended on one side and the fixing rod does not have the same diameter over its entire length, so that the jaws can not be mounted on a point at the discretion of the support rod. To this he wants to remedy the invention. The object of the invention is the task of designing a connection element that can be extended internally and by both sides. With this, bilateral elongations are possible, which could reduce the treatment time by half. It should also be possible to choose the rigidity of the connection element by exchanging various parts in parts made of different materials. The invention solves the proposed problem with a device for externally fixing parts of fractured bones having the features of claim 1. Further advantageous refinements of the invention are characterized in the dependent claims. In a preferred embodiment of the device according to the invention, it comprises a longitudinal connection element with a central axis. The connection element is bilaterally telescopic in the direction of this central axis and it is possible to mount jaws on the connecting element, to removably fix screws or bone pins. The connection element comprises a central part and two external parts movable along the central axis. Due to the displaceable external parts, the connection element can be lengthened bilaterally and has the same diameter over its length. The interchangeability of central part or respectively of the external parts allows a rigidity at the discretion of the connection element.

Another embodiment of the device according to the invention differs from the previously described embodiment in that the connecting element is constituted by a cylindrical central part and two concentric external parts in the form of hollow cylinders. The external parts are mounted on the central part so that they can slide axially and are telescopically torsionally rigid. Yet another embodiment of the device according to the invention differs from the previously described embodiments only in that the cross section of the central part has a polygonal external shape and the cross section of the external parts has a polygonal internal shape which corresponds to this external polygonal shape of the central part. Also in this embodiment the external parts are mounted axially slidable on the central part. The telescopic movement of the external parts without being able to rotate with respect to each other and with respect to the central part is guaranteed by the external polygonal shape of the central part and by means of the internally polygonal shape of the external parts. Another embodiment of the device according to the invention differs from the embodiments described above in that the external jacket surface of the central part is configured as a multiple key axis and that the external parts have an internal shape in cross section that corresponds to that. Another embodiment of the device according to the invention differs from the embodiments described above only because the axial position of the external parts with respect to the central part can be adjusted or fixed by transport screws. The transport spindles can be operated from the external ends of the connection element and allow unilateral or bilateral elongation of the connection element without the transport spindles interfering with each other. Yet another embodiment of the device according to the invention differs from the previously described embodiment in that the transport screws can be blocked by screw-in terminal parts on the external parts. Another embodiment of the device according to the invention differs from the embodiment described above in that one of the end pieces is a revolving cover and that by means of a gradual unscrewing of this energizing cap can axially release the axial tension of the threaded spindle, by means of which the external part can be displaced axially by a controllable quantity and by means of it a dynamization of the fracture can be achieved. Other embodiments of the device according to the invention differ from the embodiments described above only in that the stiffness of the connecting element can be selected by choosing the material of the central part and the external parts. For the central part, for the central part with the transport device, which can be made, for example by means of a conveyor thread, and for the external parts the following materials are conceivable: aluminum steel titanium carbon fibers. With them, combinations of various materials can also be produced for the central part and the external parts, with which the rigidity of the connection element can be influenced. Yet another embodiment of the device according to the invention differs from the forms of previously described embodiment only in that it is possible to insert an intermediate element on the central part between the external parts, which can be moved on the central part and is torsionally rigid. In addition, this intermediate element has the same external diameter as the external parts, whereby one or more clamps can be mounted on this intermediate element to fix screws or bone pins. A groove in the intermediate element passing along the longitudinal axis of the intermediate element allows the intermediate element thus grooved to be fixed on the central part due to the clamping force of a jaw mounted on the intermediate element. Instead of a single slot, the intermediate element can also have two grooves made on two opposite sides. The advantages achieved by the invention consist mainly in that the connecting element can be extended internally bilaterally and that it has the same external diameter along its entire length with the exception of a small central part. Because of this, it is possible to assemble at any point at the discretion of the connecting element, the jaws used to house and fix the bone screws. An additional intermediate element allows the positioning of one or several jaws also at a point between the external parts. It is also possible assembling the central part and the external parts that are constituted by different materials, by means of which the rigidity of the connection element can be influenced. The invention and the improvements of the invention are explained in more detail below on the basis of the partially schematic representations of several exemplary embodiments. They show: fig. 1 a lifting of an embodiment of the device according to the invention with two jaws for fixing bone screws; fig. 2 a longitudinal section through the connecting element according to an embodiment of the device according to the invention; and fig. 3 a partial view of an embodiment of the device according to the invention. Figure 1 shows an embodiment of the device according to the invention with a connection element 1 comprising the central axis 7. Coaxial to the central axis 7 are the parts 16 arranged; 17 hollow external cylindrical, the central part 8. In parts 16; 17 externally perforations are provided so that they can slide on the central part 8 and can be displaced in the direction of the central axis, whereby the connecting element becomes bilaterally telescopic. On parts 16; 17 externally removable clamps 2 are fixed for the housing and the fixation of 3 bone screws. The jaws 2 can be moved on the parts 16; 17 external along the central axis 7, and if necessary it is possible to incorporate other jaws 2. Figure 2 shows a longitudinal section through the connection element 1 according to an embodiment of the device according to the invention. The connecting element 1 comprises as telescopic elements the central part 8 and parts 16; 17 external sliding on this central part 8, being that the central part 8 and the parts 16; 17 external ones have hollow cylindrical configuration. The outer jacket surface 21 of the central portion 8 is configured as a multiple key shaft. The holes 22 at the ends 23; 24 inmates of the parties 16; 17 external ones are configured so that they correspond to this multiple key axis, so that the parts 16; 17 are telescopic in rigid torsion form. At the ends 25; 26 external axially of the central part 8 internal threads 27 are provided in which the spindles 19 can be screwed and unscrewed; 20 threaded provided for the axial displacement of the parts 16; 17 external, by which the axial length of the connection element 1 is established.

To axially fix the spindles 19; 20 threaded bushes 31 and parts 30 are incorporated; 38 terminals in the perforations of the parts 16; 17 external, at the ends 28; 29 external parties 16; 17, so that the disks 32 mounted on one of the ends 33, 34 of the spindles 19; 20 threaded are fixed axially between the bushings 31 and the parts 30; 38 terminals. If it becomes necessary to dynamize the fracture, the axial clamping of the spindle (20 threaded) can be released millimetrically by means of a gradual unscrewing of the terminal part (38). By this the outer part (17) becomes axially slidable by a controllable amount. The terminal part (38) used as the tamper cap is kept in an adjustable position and protected against loss by the elastic ring (40). Figure 3 shows an embodiment of the device according to the invention which differs from those of figure 1 and 2 in that an intermediate element 35 between the parts 16 is additionally arranged on the central part 8; 17 separate external. This intermediate element 35 is slidable on the central part 8 and is arranged torsionally rigid by means of a bore 37 corresponding to the embodiment of the multiple key shaft of the part 8. central. On one side of the intermediate element 35 there is provided a through slot (39) along the central axis (7). The axial position of the intermediate element 35 is fixed by means of the clamping force of the jaws 2, whereby the intermediate element 35 is compressed and clamped on the central part (8).

Claims (23)

1. CLAIMS 1. Device for externally fixing parts of fractured bones comprising a longitudinal connection element with a central axis, wherein A) the connection element is rigidly telescopic to the torsion in the direction of this central axis; B) it is possible to assemble jaws in removable form on the connection element, to fix bone screws; C) the connection element comprises a central part and two external parts slidable along the central axis of the central part; and D) it is possible to elongate the connection element bilaterally by the external parts that can be inserted and removed in / from the opposite ends of the central part; characterized in that E) the axial position of the external parts relative to the central part can be adjusted and fixed by transport elements arranged inside the external parts. Device according to claim 1, characterized in that the central part on one side and the external parts on the other hand are constituted of different materials, and because each part is interchangeable, with what it is possible to control the rigidity of the connection element in its entirety assembling parts made of different materials. Device according to claim 1 or 2, characterized in that the external parts have the same diameter over their entire length. Device according to one of Claims 1 to 3, characterized in that the external parts arranged at the opposite ends of the central part can be removed and inserted independently of one another. Device according to one of claims 1 to 4, characterized in that the external jacket surface of the central part is configured as a multiple key axis and the external parts have an internal shape whose cross section corresponds to that of the former. Device according to one of Claims 1 to 5, characterized in that the transport elements are transport screws which can be screwed and unscrewed in / from the central part. Device according to one of claims 1 to 6, characterized in that the transport elements configured as transport spindles can be blocked by screw-in terminal parts on the external parts. 8. Device according to claim 7, characterized in that at least one terminal part screwable on the external parts is configured as a revolving lid with an elastic ring, the dynamization consisting in which it is possible to release the axial fastening of at least one transport element millimetrically by unscrewing The at least one terminal piece can be gradually formed, by means of which it is possible to displace axially by a controllable quantity at least one external part, by means of which a dynamization of the fracture is achieved. Device according to one of claims 1 to 8, characterized in that on the central part it is possible to insert at least one intermediate element between the external parts, which is slidable and rigid to the torsion on the central part and can be fixed on the central part in a desired position. Device according to claim 9, characterized in that at least one clamp can be mounted on the external circumference of the intermediate element. 11. Device according to claim 9 or 10, characterized in that a through slot is provided along the central axis on one side of the intermediate element. Device according to claim 9 or 10, characterized in that a through groove is provided length of the central axis on two opposite sides of the intermediate element. Device according to one of Claims 9 to 12, characterized in that the intermediate element can be compressed by the clamping force of the clamp and thereby fixed on the central part. Device according to one of claims 9 to 13, characterized in that the external parts are made of aluminum. Device according to one of claims 9 to 13, characterized in that the external parts are made of steel. Device according to one of claims 9 to 13, characterized in that the external parts are made of a carbon fiber material. Device according to one of claims 9 to 13, characterized in that the external parts are made of titanium. Device according to one of claims 9 to 17, characterized in that the central part is made of aluminum. Device according to one of claims 9 to 17, characterized in that the central part is made of steel. 20. Device according to one of claims 9 to 17, characterized in that the central part is made of a carbon fiber material. Device according to one of claims 9 to 17, characterized in that the central part is made of titanium. Device according to one of claims 9 to 21, characterized in that the external surfaces of the external parts extending coaxial to the central axis are rotationally symmetrical. Device according to one of the claims 9 to 22, characterized in that the central part has a polygonal outer shape in cross section, and the external parts have a polygonal internal shape in correspondence with this external polygonal shape.