Improved external fixation strut

Abstract

The present disclosure relates to an improved external fixation strut comprising the following components: an external fixation strut comprising an elongate body with first and second hollow tubular shafts; opposite connectors respectively connected to the ends of the first or second shafts, each connector including a ball-and-socket joint; one shaft having an inner diameter slightly larger than the outer diameter of the other shaft for slidably and telescopically receiving the other shaft therein; the first and second shafts of the strut being made of a radiolucent synthetic plastic material; clamping elements provided near the overlapping ends of the first and second shafts for providing a quick gripping action to stop the telescopic sliding of one shaft inside the other shaft; a manually operated fixation element acting on the clamping element to effect the quick gripping action; a sleeve provided around a central portion of the strut where the first and second shafts overlap; and a clamping band located around the sleeve and including opposing gripping portions connected by a threaded connector. Also disclosed is a fixation system including at least first and second fixation rings and / or at least fixation arches interconnected by at least one of said fixation struts.

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to improved structures for external fixation systems and devices, and more particularly to improved external fixation posts. [Background technology]

[0002] The present invention is described in terms of external fixation devices, particularly connecting posts and rods. Generally speaking, external fixation devices are commonly used in various surgical procedures, such as limb fractures, limb lengthening, and deformity correction. The method involves a rigid framework comprising several rings or arches placed externally around the limb, which are attached to bone segments using wires and half pins inserted into the bone segments and connected to the relevant parts of the external rigid framework.

[0003] The opposing rings of the rigid framework are connected to each other either directly or with uniplanar or multiplanar hinges by threaded and / or telescopic rods, which allow the surgeon to adjust the position of the rings relative to each other longitudinally, rotationally, horizontally or angularly over time.

[0004] For example, in limb lengthening, a bone is surgically divided into two sections, and wires and half pins are inserted into the bone segments above or below the surgical bone cut and attached to rings of a rigid framework interconnected by struts or telescoping connecting rods.

[0005] In the case of limb lengthening, the opposing rings are directly interconnected by at least three or four threaded or telescopic rods whose length can be regularly adjusted and which allow for gradual separation of the bone segments longitudinally.

[0006] A rigid framework is used to gradually push the two bone segments apart longitudinally over a period of time (e.g., 1 millimeter per day), allowing bone to gradually form in the gap between the bone segments created by this distraction technique. Once the desired amount of distraction is achieved (e.g., 5-6 cm), the external apparatus is stabilized in a fixed position and left on the bone segments until mineralization of the newly formed bone is complete (e.g., 3-6 months, depending on the nature of the pathology and the amount of distraction).

[0007] Similarly, in deformity correction, the bone is surgically divided into two portions (usually at the apex of the deformity), and wires and half pins are inserted into the bone segments above or below the surgical bone cut and attached to rings of a rigid framework. Again, the opposing rings of the rigid framework are connected together by threaded rods to an attachment hinge and an angular distractor that gradually pushes the two bone segments angularly apart over a period of time.

[0008] [Prior art] One common fixation device is a circular metal structure known as the Ilizarov device. When used for limb lengthening or deformity correction, the Ilizarov device consists of several rings or arches that are placed externally around the limb and attached to surgically separated bone segments using wires and half pins. For angular deformity correction, the opposing rings of the Ilizarov device are connected by a pair of hinges that provide an axis of rotation for the bone segments and an angular distractor that gently pushes the two rings and associated bone segments apart.

[0009] Another common external fixator is known as the Taylor Spatial Frame, a hexapod external fixator based on the so-called Stewart platform, but it shares many elements and features of the Ilizarov device.

[0010] The Taylor Spatial Frame consists of two external fixator rings attached to bone segments by wires and half pins, connected together by five or six telescoping struts at multiplanar hinges at each end of the struts. Each strut can be lengthened or shortened as needed to pull the two interconnected ring segments toward or push them away from each other.

[0011] Each strut in the Taylor Spatial Frame has a threaded rod partially positioned inside a hollow shaft that includes an adjustment nut that mates with the threaded rod. However, performing quick or slow strut length adjustments is time consuming, and replacing struts with longer ones during treatment is often required.

[0012] Furthermore, without the use of external support or other stabilization mechanisms to support the rest of the frame, it is not possible to replace or remove posts from a Taylor Spatial Frame during the course of treatment because if one post were to be removed from the frame, it would become unstable and collapse.

[0013] Other examples of this type of fixation device are commercially known as TrueLok and Sheffield, the latter of which is shown in FIG.

[0014] These solutions are often used to solve traumatic bone situations where it is very important for the surgeon to quickly reduce the fracture and check the results of the reduction by radiography using X-rays.

[0015] Both of the above-mentioned products allow for the attachment of a post that has the ability to quickly connect to a corresponding ring to quickly free the second ring relative to the first. This simple attachment system allows for the reduction and stabilization of a fracture in a relatively short amount of time, and also allows for adjustment of the relative inclination between the rings.

[0016] However, both types of products have some drawbacks.

[0017] First, the strut is an obstruction in any x-ray image, often obscuring the visibility of the fracture to the surgeon.

[0018] Secondly, while relatively easy to install, the above known solutions require a relatively long time to assemble and place on the patient, also because the posts have an inherent weight that makes them uncomfortable to apply to the patient.

[0019] Furthermore, transport and storage of these known external fixation devices is always complicated due to their size and encumbrance.

[0020] An external fixation device based on the prior art is described, for example, in the prior art document U.S. Patent Application Publication No. 2016 / 199099. 、 Chinese Patent Application Publication No. 103 494 634 and U.S. Patent Application Publication No. 2020 / 0000492 is disclosed in.

[0021] The technical problem underlying the present invention is to provide a novel post for an external fixation device and a novel fixation device design having functional and structural features that overcome the drawbacks affecting prior art solutions.

[0022] The primary objective of the improved external fixation strut of the present disclosure is to improve the surgeon's visibility of the fracture site while allowing easy axial movement of the strut for possible micrometric dynamization. Summary of the Invention

[0023] The solution idea underlying this disclosure is to realize the main part of the ring interconnecting the struts in a radiolucent material that utilizes articulations to host micrometric regulation of the strut length.

[0024] According to such a solution idea, the technical problem underlying the invention is solved by an improved external fixation strut comprising the following elements: an elongate body having first and second hollow tubular shafts; opposite connectors respectively coupled to the ends of the first and second shafts, each connector including a ball joint; one shaft having an inner diameter slightly larger than the outer diameter of the other shaft for hosting the other shaft therein in a slidably and telescopic manner; the first and second shafts of the struts are realized by a radiolucent synthetic plastic material; a clamping element provided near the overlapping ends of the first and second shafts to provide a fast gripping action to stop telescopic sliding of one shaft inside the other shaft; A manually operated fixing element acting on the clamping element to effect said rapid gripping action.

[0025] Various embodiments of the improved external fixator post are included in the present disclosure. In one embodiment, the external fixator post includes the following elements: a sleeve disposed around a central portion of the support where the first and second shafts overlap; A clamp band positioned around the sleeve and including opposite and facing gripping portions, at least one of which has a threaded central bore for receiving a threaded shaft of a clamping bolt, the clamping bolt having a head connected to a removable manually operated key.

[0026] Also included in the present disclosure are various embodiments for a fixation system comprising at least first and second fixation rings and / or at least fixation arches interconnected by several fixation struts, where at least one of said fixation struts comprises the following elements: an elongate body having first and second hollow tubular shafts; two connectors respectively connected to the ends of the first and second shafts, each connector including a ball joint; one shaft having an inner diameter slightly larger than the outer diameter of the other shaft for hosting the other shaft therein in a slidably and telescopic manner; the first and second shafts of the strut being realized by a radiolucent synthetic plastic material; a clamping element provided near the overlapping ends of the first and second shafts to provide a fast gripping action to stop telescopic sliding of one shaft inside the other shaft; a manually operated fixing element acting on the clamping element to effect said rapid gripping action; a sleeve disposed around a central portion of the support where the first and second shafts overlap; A clamp band positioned around the sleeve and including opposite and facing gripping portions, the gripping portions being connected by a threaded connector.

[0027] Furthermore, in the above-described fastening system, each strut comprises opposing male and female connectors, each including a ball-and-socket joint that allows angular movement of the corresponding strut through a spherical angle of at least 90° to collapse the above-described fastening system for packaging and transport purposes. [Brief explanation of the drawings]

[0028] For a more complete understanding of the features and advantages of the present disclosure, reference is now made to the following detailed description of the disclosure taken in conjunction with the accompanying drawings, in which:

[0029] [Figure 1] 1 is a perspective view of an embodiment of an external fixation system including a post according to the prior art; FIG. [Figure 2]1 is a schematic perspective view of an embodiment of an external fixation post of the present disclosure. FIG. [Figure 2A] 1 is a perspective view of the components of an external fixation post of the present disclosure; FIG. [Figure 2B] FIG. 2B is a cross-sectional view of the components shown in FIG. 2A when attached to an external fixation post of the present disclosure. [Figure 3] FIG. 2 is a schematic perspective view of the central portion of the support post of the present disclosure. [Figure 3A] FIG. 12 is a schematic perspective view of the central portion of the external fixation post of the present disclosure with the nuts and bolts that secure the clamping band on the central sleeve removed. [Figure 4] 10A-10C show another schematic perspective view of the external fixation post of the present disclosure in a different configuration. [Figure 5] 1 is a perspective view of one embodiment of an external fixation system including a post implemented in accordance with the present disclosure; FIG. [Figure 6A] FIG. 10 is another perspective view of a further embodiment of an external fixation system including at least three posts realized in accordance with the present disclosure. [Figure 6B] FIG. 6B is a perspective view of the embodiment of FIG. 6A in a folded configuration. [Figure 7A] FIG. 7C is a cross-sectional view of the external fixation strut of the present disclosure from an opposite perspective to that of FIG. 7B. [Figure 7B] 7B is a cross-sectional view of the external fixation strut of the present disclosure from an opposite perspective to that of FIG. 7A. [Figure 8] FIG. 1 is a perspective view of a male connector associated with one end of an external fixation post of the present disclosure. [Figure 9] FIG. 9 is a cross-sectional view of the male connector of FIG. 8. [Figure 10] FIG. 1 is a perspective view of a female connector associated with one end of an external fixation post of the present disclosure. [Figure 11A] FIG. 11 is a cross-sectional view of the female connector of FIG. [Figure 11B] 11B is a further cross-sectional view of the female connector of FIG. 11A taken from a perpendicular perspective. [Figure 12A] FIG. 11 is another perspective view of the female connector of FIG. 10. [Figure 12B] 11 is another perspective view of the female connector of FIG. 10, in which the internal spring-loaded mechanism is visible. [Figure 12C] FIG. 12C is a slightly enlarged cross-sectional view of the female connector of FIG. 12B. [Figure 13A] 13B and 13C show enlarged cross-sectional views of the female connector of the present disclosure in a different configuration. [Figure 13B] 13B shows an enlarged cross-sectional view of a female connector of the present disclosure in a different configuration than that shown in FIGS. 13A and 13C. FIG. [Figure 13C] 13A and 13B show enlarged cross-sectional views of the female connector of the present disclosure in a different configuration. [Figure 14A] 14B and 14C show enlarged cross-sectional views of an alternative embodiment of the female connector of the present disclosure in a different configuration. [Figure 14B] 14B shows an enlarged cross-sectional view of an alternative embodiment of the female connector of the present disclosure in a different configuration than FIGS. 14A and 14C. [Figure 14C] 14A and 14B show enlarged cross-sectional views of alternative embodiments of the female connector of the present disclosure in a different configuration. [Figure 15A] 15B and 15C show enlarged cross-sectional views of further embodiments of female connectors of the present disclosure in a different configuration. [Figure 15B] 15B shows an enlarged cross-sectional view of a further embodiment of a female connector of the present disclosure in a different configuration than that of FIGS. 15A and 15C. [Figure 15C] 15A and 15B show enlarged cross-sectional views of further embodiments of female connectors of the present disclosure in a different configuration. DETAILED DESCRIPTION OF THE INVENTION

[0030] While the making and use of various embodiments of the present disclosure are discussed below, it should be appreciated that the present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the present disclosure and do not delimit the scope of the disclosure.

[0031] FIG. 2 shows a schematic diagram of an improved external fixation strut 200 according to the present disclosure, having an elongated shape with opposite ends provided with connectors 201, 202 configured to be attached to respective fixation rings or arches of an external fixation device.

[0032] The ring of the external fixation device to which the strut 200 is attached is shown in other figures described later.

[0033] The strut 200 has a main elongate body formed by a pair of coaxially aligned hollow tubular shafts 210 and 220. In the disclosed embodiment, the shafts have a cylindrical shape, although other shapes are possible.

[0034] In the exemplary embodiment disclosed herein, the first shaft 210 has an inner diameter that is slightly larger than the outer diameter of the second shaft such that the second shaft 220 can be slidably received within the first shaft 210. That is, the second shaft 220 can slide along the internal cavity of the first shaft 210.

[0035] The dimensional relationship between the first shaft 210 and the second shaft 220 provides a telescopic configuration to the ensemble of struts 200 whose length can be adjusted as needed to maintain the interconnected rings in a predetermined relative spatial relationship.

[0036] The shafts 201 and 220 of the strut 200 are made of a synthetic plastic material that is radiolucent, ie that allows X-rays to pass through.

[0037] As a possible example, these shafts may be realized in a techno-polymeric material, such as PEEK (polyetheretherketone). This techno-polymer is characterized by excellent heat and chemical resistance. Furthermore, it supports sterilization cycles, is resistant to ionizing radiation, and presents good tribological, mechanical, and dielectric properties that make it a good alternative to metallic materials.

[0038] A sleeve 230 is provided around the central portion of the strut 200 where the first shaft 210 and the second shaft overlap, or better, near the ends where the first shaft and the second shaft overlap.

[0039] The sleeve 230 presents a recess hosting a clamp band 204 having opposing gripping portions 205, 206 that move toward one another upon operation of a removable manual key 250, e.g., a butterfly key.

[0040] The grippers 205, 206 have aligned through holes 211 that are traversed by the threaded shaft 215 of the clamping bolt 260. The threaded shaft is received at its free end in a threaded nut 207 and set on the opposite side of the grippers 205, 206 relative to the head 261 of the clamping bolt. In an alternative embodiment, the clamping bolt 260 may be received in a threaded hole in one of the grippers 205, 206 instead of engaging a loose threaded nut.

[0041] Tightening of the clamping bolt 260 within the threaded nut 207 draws the grippers 205, 206 closer together. The head 261 of the clamping bolt 260 is connected to the removable manual operation key 250.

[0042] More specifically, the manual key 250 may be structured as a knob or butterfly wrench that can manually operate a clamping bolt that brings one of the two parts 205, 206 closer to the other. The threaded shaft 215 is part of a bolt 260 that has a recessed head, and the manual key 25 is mechanically coupled to such bolt 260 in a removable manner.

[0043] By operating the butterfly wrench 250, the operator can stop the relative axial movement of one shaft 220 sliding inside the other shaft 210, and thus adjust the axial main extension of the strut 200. This is done by manually and quickly pre-closing the telescopic stroke of the strut 200.

[0044] The butterfly wrench 250 is removably associated with one 206 of the two opposing gripping portions 205, 206 and may be removed leaving exposed the recessed head of the bolt 260 which can receive and host a key or tightening tool as will be disclosed in more detail later with respect to other figures.

[0045] The external fixator strut 200 of the present disclosure has connectors 201, 202 including ball joints that are associated with both ends of the external fixator strut 200 and are attachable to the outer or inner surface of a fixation ring or arch. These ball joint connectors 201, 202 are associated with male and female final connectors 280, 290, respectively, for quicker connection to corresponding rings of the ring fixator.

[0046] At least one 201 of these ball joint connectors 201, 202 is housed in an adjustment mechanism 212 that allows for independent, rapid, incremental and fine dynamization adjustment of the length of the strut 200, as will be seen in the remainder of this description.

[0047] The adjustment mechanism 212 can be thought of as an on-off dynamization section that allows the surgeon to thread from a rigid post to a resilient post with an axis of at least 3 mm without movement under load. Dynamization is achieved by a deformable element, for example, a spring-like resilient element housed inside the distal portion of the shaft, specifically the female connector. Two alternative embodiments of the dynamization mechanism 212 are disclosed below.

[0048] 2A shows a perspective view of a component of the presently disclosed external fixator strut 200. More specifically, this component is a sleeve 230 disposed around the overlapping inner ends of the first and second shafts 210, 220.

[0049] The sleeve 230 is structured with a first sleeve portion 225 having an inner diameter that corresponds approximately to the outer diameter of the first shaft 210, and a second sleeve portion 235 having an inner diameter that corresponds approximately to the outer diameter of the second shaft 220.

[0050] The first and second sleeve portions 225 and 235 are integrally formed as a single piece construction.

[0051] More specifically, the second sleeve portion includes two opposing semi-tubular wings 227, 237 that protrude from the first sleeve portion 225 and are separated from each other by an air gap 229. There, the two tubular wings 227, 237 have inner surfaces facing one another to substantially form the second sleeve portion 235 that appears to be longitudinally open along the opposing air gap 229 and that has a smaller diameter when compared to the diameter of the first sleeve portion 225.

[0052] The smaller diameter of the second sleeve portion 235 produces a radial step 232 between the second and first sleeves 235, 225 where they are linked.

[0053] A collar 228 is provided at the free end of each of the annular wings 227 and 237. The collar 228 from one side and the radial step 232 from the other side define with the tubular wings 227 and 237 an annular space in which the clamp band 204 is hosted.

[0054] FIG. 2B shows a cross-sectional view of a sleeve 230 attached to an improved external fixation post of the present disclosure.

[0055] From this cross-sectional view, it can be seen that when the first sleeve portion 225 is fixed around and over the inner end 240 of the first shaft 210, the other sleeve portion 235 abuts against such inner end 240 in correspondence with the radial step 232.

[0056] The second shaft 220 has an inner end 245 that faces to the inner end 240 of the first shaft 210 and is slidable within the first shaft in a telescopic manner. The inner end 245 of the second shaft is closed by a cap 248, which is considered the end of the stroke.

[0057] The clamp band 204 is hosted in an annular space or recess in the second sleeve 235 between the radial step 232 and the collar 228 .

[0058] In this view, one gripping portion 205 of the clamp band 204 is visible, which has a threaded nut 207 for receiving the threaded shaft of the butterfly wrench 250 .

[0059] As the gripping portions 205 and 206 are brought closer together by the butterfly wrench 250, a tight pressure around the second sleeve is obtained by the clamping action performed by the clamping band 204. This clamping action provides a rapid gripping action that stops the telescopic sliding of the second shaft 220 inside the first shaft 210.

[0060] 3 shows another perspective view of one embodiment of the external fixator post of the present disclosure for an outer ring fixation device. The external fixator post 200 is shown at its central portion where two shafts 210 and 220 overlap in a telescopic manner.

[0061] The sleeve portion 230 encases a central portion of the strut 200 where the first shaft 210 and the coaxial second shaft 220 overlap.

[0062] The clamp band 204 is hosted and mounted in a recessed portion of the second sleeve portion 235 with its opposing gripping portions 205 , 206 projecting laterally from the sleeve portion 230 .

[0063] A threaded nut 207 housed in a seat on the gripper 205 receives the threaded shaft 215 of a clamping bolt 260 having a polygonal, for example hexagonal, head.

[0064] The butterfly wrench 250 is placed against the head of the bolt 260 with the protruding flanges 270 regularly arranged in a polygonal layout that generally corresponds to the faces of the polygonal head of the bolt 260 .

[0065] Of course, other configurations may be employed. For example, wrench 250 may be structured with a polygonal hole that fits or puts on the polygonal head of clamping bolt 260.

[0066] In other words, the butterfly wrench 250 is a user adaptor for the clamping bolt 260 that allows the user to perform a faster and stronger manual gripping action that brings one of the two parts 205, 206 closer to the other through the threaded action of the bolt 260.

[0067] By operating this butterfly wrench 250, the operator can stop the relative axial movement of one shaft sliding inside the other shaft, thus adjusting an axial main extension of the strut 200.

[0068] 3A shows another perspective view of one embodiment of the external fixator post of the present disclosure for an outer ring fixation device. The external fixator post 200 is shown in a central portion where two shafts 210 and 220 overlap in a telescopic manner.

[0069] In this view, the clamping bolt 260 and the corresponding threaded nut 207 that clamp the grippers 205, 206 are shown in an exploded state. The aligned threaded holes 211 of the grippers are therefore clearly visible. The hole in gripper 205 is enlarged at the seat intended to receive the threaded nut 207.

[0070] 4 shows a schematic perspective view of the external fixation strut 200 of the present disclosure with the butterfly wrench 250 removed after a preliminary manual closing operation of the telescopic stroke of the strut 200 without needing access to an external key, in order to reduce the time and complexity of the operation. Finally, said wrench 250 is manually removed and definitive locking is performed with the help of a key.

[0071] Without the butterfly wrench 250, the bolt heads are exposed and the arrangement employed can be tightened using a key.

[0072] FIG. 5 is a perspective view of one embodiment of an external fixation system 500 including a strut 200 made in accordance with the present disclosure.

[0073] The fixation system 500 includes at least a pair of fixation rings 510 and 520. Alternatively, at least one of the fixation rings may be a fixation arch (not shown), for example, at a distal portion of the fixation system 500.

[0074] The fixation rings 510 and 520 are interconnected through several fixation posts 200, for example at least three or four posts, as described above, although nothing prevents a system configuration including a larger number of posts, for example six.

[0075] Each of the struts 200 is structured as disclosed in the previous passage of this disclosure, however, due to the need to have at least one strut provided with special dynamization features, at least one strut having a different configuration may be used.

[0076] In other words, the above-described fastening system 500 may include at least one strut 200 according to the present disclosure.

[0077] Preferably, the struts 200 are connected to the rings 510 and 520 through opposite connectors 201, 202, namely a male connector 201 and a female connector 202.

[0078] The connectors cooperate with holes (not shown) regularly spaced along the ring or arch and are fixed to the ring or arch through fixing bolts 530 .

[0079] Each connector is further associated with a ball joint to allow angular movement of the corresponding strut through a spherical angle of at least 90° and an operating angle of at least 45°.

[0080] The angular flexibility of connectors 201 and 202 allows fastening system 500 to be collapsed for packaging and transport purposes.

[0081] Furthermore, the above-described system 500 may be structured in a pre-assembled configuration that is prepared in a sterile environment and then packed for subsequent rapid use by the surgeon.

[0082] FIG. 6A shows a perspective view of a further embodiment of an external fixation system 600 including three posts 200 implemented in accordance with the present disclosure.

[0083] The strut 200 shown in this figure does not present the butterfly wrench 250. That is, the telescopic length of the strut 200 is already adjusted, and the use of ball joints 201 and 202 at both ends allows the entire structure to be folded in the direction of the curved arrow 650 to obtain a generally flat configuration of the fastening system 600.

[0084] Thus, thanks to the possibilities offered by the angle of the ball joints up to 90°, it is possible to preassemble a fastening system comprising at least two rings and two to four support posts already assembled and folded, which is supplied in a reduced size and in a sterile package.

[0085] FIG. 6B shows a perspective view of the embodiment of FIG. 6A in a collapsed configuration.

[0086] The connecting elements 201 and 202 can be angled up to 90°, allowing the two rings 510 and 520 to lead together with the connecting strut 200 in a substantially coplanar manner, as shown in FIG. 6B.

[0087] The 90° angle can be achieved on both the female and male ends thanks to a larger slot on the connecting element, which will be described in detail later. The other slots remain the same as those of the current strut.

[0088] 7A shows a cross-sectional view of the external fixation strut of the present disclosure. The two shafts 210 and 220 overlap in a telescopic manner, and sleeve portions 225, 227 encase the central portion of the strut 200 where the first 210 and coaxial second shaft 220 overlap.

[0089] A recessed portion 204 of the second sleeve portion 225 is provided to host a clamp band.

[0090] FIG. 7B shows another cross-sectional view of the external fixator post of the present disclosure from an opposite perspective.

[0091] In this FIG. 7B, the gripping portion 205 traversed by the threaded shaft 205 of the clamping bolt is clearly visible.

[0092] A dynamization mechanism 212 is associated with the female connector 202. However, an alternative embodiment cannot be excluded in which the above dynamization mechanism is reversed and associated with the male connector 201.

[0093] FIG. 8 is a perspective view of a male connector 201 associated with one end of a post 200 according to the present disclosure.

[0094] More specifically, male connector 201 comprises a pair of stages 840 and 850 associated with and linked in a mechanical sequence to one free end 810 of second shaft 220. First stage 840 is an interconnection stage for ball-and-socket joint stage 850, which brings threaded rod 280 of male connector 201.

[0095] The first stage 840 includes a support element 845 for a rod 842 connected to the end 810 of the second shaft and having an end portion configured as a ball cage 848 for a ball joint of the second stage 850.

[0096] The support element 845 is associated with a base 830 fixed to the free end 810 of the second shaft 220 and presents a central portion having at least two opposing flat surfaces 846 provided to allow insertion of an operating key (not shown).

[0097] The rod 842 may be structurally independent from the support element 845 or may be integrally formed with such a support element. In the first case, the rod 842 protrudes from a central hole in the support element 845 so as to be substantially coaxial with the second shaft 220.

[0098] The second stage 850 comprises a ball 855 for a ball joint, where the ball cage 848 represents the socket and threaded rod 280 integrally formed with the ball 855 .

[0099] The more protruding portion of this threaded rod 280 represents a male connection for one or other of the fixation rings 510, 520 of the fixation system 500. More specifically, the threaded rod 280 may be inserted into one of a number of holes typically provided in the fixation ring and secured by a clamping bolt 530.

[0100] A special closure cap 890 is attached to the threaded rod 280 and closes the socket of the ball joint formed by the ball cage 848 and the ball 855 .

[0101] This particular closure cap 890 is formed by two cylindrical portions having different diameters: a first higher or thicker portion 870 includes a pair of opposing flat surfaces 860 to allow insertion of an operating key (not shown).

[0102] This first portion 870 has a knurled or milled surface 875 to improve adherence between the male connector 201 and the corresponding ring 510 or 520 of the fastening system 500.

[0103] A second, smaller portion 880 of the closure cap 890 has a larger diameter and a knurled or milled surface 885 to allow manual rotation by an operator.

[0104] A more detailed description of the internal structure of the male connector 201 is reported in the following disclosure of FIG. 9, and parts and components having the same structure and function of the elements disclosed in FIG. 8 bear the same reference signs.

[0105] FIG. 9 is a schematic perspective view of a cross section of the male connector 201 already disclosed with respect to FIG.

[0106] The first stage 840 is coupled to the end 810 of the second shaft 220 and includes a special shaft end element 940 .

[0107] The shaft end element 940 has a first portion 942 that is press-fitted or fixed onto the end 810 of the second shaft, in particular, within such end. A second intermediate portion 944 encases the end 810 as a surrounding collar, while a third extension portion 946 is provided for interconnection with a support element of the interconnection stage 840.

[0108] The second intermediate portion 944 corresponds to the base portion 830 shown in FIG.

[0109] Additionally, extension portion 940 is externally threaded and presents a passing hole 948 for hosting rod 842 that supports ball joint stage 850 .

[0110] The rod 842 passes through the hole 948 and a further hole in the support element 845 .

[0111] The support element 845 is threaded at the end of the stroke into the outer threaded portion of the intermediate portion 944 , ie, the extension portion 946 adjacent the base 830 .

[0112] However, the threading action of the support element 845 can be adjusted to obtain controlled micrometer axial movement of the entire support post 200 when attached to the opposing locking rings 510, 520.

[0113] In other words, by manipulating the number of turns of the screwed coupling between the support element 845 and the externally threaded extension 946, the stroke of the entire support 200 when mounted between the two rings 510, 520 can be controlled very precisely.

[0114] Ball cage 848 is the protruding portion of rod 842 and represents the seat or socket for ball joint stage 850 .

[0115] The ball 855 is formed in one-piece construction with a threaded rod 280 which also presents an enlarged diameter 960 closer to the ball 855 and is provided with an outer threaded surface 965 .

[0116] A special closure cap 890 is threaded onto the outer threaded surface 965 of the rod portion 280 having the expanded diameter 960 up to the moment wherein the second, smaller portion 880 of the closure cap 890 abuts the ball cage 848.

[0117] From the cross section of Figure 9, the interior portion of the closure cap 890 has a hemispherical shape 970 which defines a sort of closure for the ball cage 848 and together with the ball cage 848 defines a spherical chamber within which the balls 855 of the ball joint move angularly.

[0118] FIG. 10 is a perspective view of a female connector 202 associated with one end of a post 200 according to the present disclosure.

[0119] More specifically, the female connector 202 is associated with one free end 1010 of the first shaft 210 and comprises a pair of stages 1040 and 1050 linked in a mechanical sequence. The first stage 1040 is a joint stage for the final stage 1050, which includes a female element 1060.

[0120] The first joining stage 1040 is connected to the end 1010 of the first shaft 210 and includes a support element 1045 that is attached to the end 1010 of the shaft 210 as a closure cap but is coupled to the base 1020 of the ball joint 1030.

[0121] The support element 1045 has a closure collar 1046 that abuts the end 1010 of the shaft 210 .

[0122] The base 1020 has an outer threaded portion 1025 and is connected to a support element 1045 by a threaded adjustment ring 1035. This ring 1035 is part of the adjustment mechanism 212, disclosed in more detail with reference to FIG. 11 below, which has a knurled or milled peripheral surface to allow manual rotation by an operator.

[0123] Advantageously, the adjustment ring is made of a reinforced plastic material that is transparent to X-ray radiation.

[0124] A ball joint 1030 protruding from the base 1020 has a number of regularly spaced openings 1037, for example four openings, one of which, opening 1033, is larger than the other openings 1037.

[0125] The final stage 1050 of the female connector 202 has a more distal portion 1055 connected to the ball joint 1030 and a proximity and final cylindrical portion 1090 including an internally threaded female element 1060 for receiving an interconnecting bolt (not shown) for connecting one end of the strut 200 to a ring of the fixation system 500.

[0126] The proximal final cylindrical portion 1090 is provided with opposing flat surfaces 1070 for insertion of an operating key, while the distal portion 1055 has an enlarged annular ferrule 1080 with a knurled or milled peripheral surface to allow manual rotation by the operator.

[0127] FIG. 11A shows a cross-sectional perspective view of the same female connector 202 of FIG. 10, but in greater detail shows the previously described adjustment mechanism 212 that allows for independent, rapid, incremental, and fine adjustment of the overall length of the strut 200.

[0128] As before, parts and components having the same structure and function as those already disclosed are identified with the same reference signs.

[0129] From this cross-sectional view, it can be seen that the ball joint 1030 protrudes from the externally threaded base 1020 .

[0130] The above special structure including the ball joint 130 and its base 1020 is mounted on a support element 1045 fixed at the end 1010 of the shaft 210 and presents a passing hole 1110 hosting a pin 1120 having a T-shaped inner shaft 1125 that slides within a hole 1135 of the support element 1045 and an extension portion 140 that slides along the passing hole 1110.

[0131] A first transverse pin 1148 is fixed to the support element 1045 and crosses the stem of the inner shaft 1125 at its distal portion.

[0132] The support element 1045 is made of a synthetic plastic material that is transparent to X-ray radiation and may be considered as a plastic sleeve that closes the end 1010 of the shaft 210 while simultaneously providing a seat for the dynamization mechanism that will be disclosed later.

[0133] More specifically, the support element 1045 is structured as a kind of double sleeve having a portion that is inserted into the shaft end 1010, a collar 1046 that abuts the shaft end 1010, and a protrusion 1047 that slidably supports a portion inside the base 1020 of the first stage 1040.

[0134] The T-shaped inner shaft 1120 is advantageously realized by a component of radiolucent material, for example aluminum, or alternatively, reinforced plastic material.

[0135] A resilient element 1150 is provided inside the support element 1045. More specifically, the spring 1150 is wound around the shank 1125 of the inner shaft 1120 inside the support element 1045 to provide a resilient action in cooperation with the screwing action of the threaded adjustment ring 1035 on the outer threaded portion 1025 of the base 1020.

[0136] A second transverse pin 1142 is fixed at the base 1020 and crosses the extension 1140 of the T-shaped inner shaft 1120. This second transverse pin 1142 is slidable within an elongated buttonhole-like slot 1122 that is centrally formed in and aligned with the major axis of the T-shaped inner shaft 1120. Relative movement between the support element 1045 and the base 1020 of the first stage 1040 is accompanied by corresponding relative movement of the second transverse pin 1142 within the elongated slot 1122.

[0137] The following components all together form the dynamization adjustment mechanism 212: support element or plastic sleeve 1045, base 1020 i.e. threaded portion 1025, threaded adjustment ring 1035, T-shaped inner shaft 1120, and spring 1150.

[0138] The dynamization adjustment mechanism 212 in this embodiment includes a T-shaped inner shaft 1120 made of plastic material assembled to a plastic support element 1045 with a first transverse pin 1148 used to assemble the two plastic parts. A second transverse pin 1142 is used as a mechanical stop for compression of the spring 1150 and to avoid any accidental disassembly of the strut.

[0139] The threaded adjustment ring 1035 can be manually manipulated to adjust the excursion of the base 1020 together with the ball joint 1030 with respect to the end 1010 of the shaft 210 and against the elastic action of the spring 1150. In this manner, it allows for smooth, independent, rapid, incremental, and fine adjustment of the overall length of the strut 200 through this adjustment mechanism 212.

[0140] In a preferred embodiment, this adjustment in length is an adjustment of at least 3 millimeters.

[0141] The construction of the female connector 202 is completed in the final stage 1050 by a spring-loaded mechanism 1100 mounted around the female element 1060 .

[0142] More specifically, the female element 1060 of the female connector 202 is realized at the end of a rod 1160 that is slidable inside a tubular bore 1180 formed by first and second coaxial tubular chambers 1180, 1190 having different diameters, and is realized internally relative to a proximal final cylindrical portion 1090.

[0143] The rod 1160 has a threaded distal portion 1195 for screwing into a corresponding seat provided in the ball joint 1030 .

[0144] The spring biasing mechanism 1100 includes a spring 1111 hosted within a first tubular chamber 1180 that encases a more proximal portion of a rod 1160 from which the female element 1060 is formed.

[0145] The rod 1160 extends through an opening 1133 in the ball joint 1030, which is in communication with a larger opening 1033 in the ball joint 1030 that allows the final stage 1050, including the proximal cylindrical portion 1090 of the female element 1060, to rotate around the ball joint 1030 by at least 90°.

[0146] By manually manipulating the expanded annular ferrule 1080 of the distal portion 1055, the penetration of the threaded distal portion 1195 of the rod 1160 into the corresponding seat of the ball joint can be adjusted, and thus the relative spacing between the last stage 1050 and the first stage 1040. This allows angular movement between the first and last stages 1040, 1050 to reach a 90° "foldable" configuration of the connector 202, which differs from the working configuration, which ranges from 0° to 45°.

[0147] FIG. 11B shows a cross-sectional perspective view of the same female connector 202 of FIG. 11A from a vertical perspective.

[0148] The components shown in this figure are the same and report the same reference numbers as in FIG. 11A.

[0149] In this view, the T-shaped inner shaft 1120, made of plastic material and integrated into the plastic support element 1045, together with the first transverse pin 1148, which is used to connect the two plastic parts, is particularly evident. The second transverse pin 1142 is also evident and is used as a mechanical stop for the compression of the spring 1150 and to avoid any accidental disassembly of the strut.

[0150] The threaded adjustment ring 1035 is shown in a position closer to the base 1020 and spaced apart from the end 1010 of the shaft 210 with the spring 1150 released.

[0151] The larger opening 1033 of the ball joint 1030 is also shown compared to the smaller opening 1037 on the other side.

[0152] 12A is another perspective view of the female connector of FIG. 10 from a different vantage point.

[0153] FIG. 12B is a perspective view of the female connector of FIG. 10, showing the internal spring biasing mechanism 1100 including a spring 1111 wrapped around a rod 1160.

[0154] Rotation of the annular ferrule 1080 of the distal portion 1055 may adjust the compression of the spring 1111 .

[0155] 12C is a slightly enlarged cross-sectional view of the female connector of FIG. 12B, more specifically of the stage 1050 at its end, in which the distal threaded portion 1195 of the rod 1160 threaded into a seat provided in the ball joint 1030 is clearly visible.

[0156] Rotation of the annular ferrule 1080 adjusts the cohesion between the final stage 1050 and the first stage 1040, including the ball joint 1030, allowing the final stage 1050 to rotate for greater angular movement to reach the 90° "foldable" configuration.

[0157] FIG. 13A shows a cross-sectional view of the first stage 1040 of the female connector 202 and the adjustment mechanism 212 that allows for independent, rapid, incremental, and fine adjustment of the length of the struts 200.

[0158] As can be appreciated, when the adjustment ring 1035 abuts the closure collar 1046 of the support element 1045, the screwing action of the adjustment ring can be exerted on the outer threaded portion 1025 of the base 1020, thus moving the base 1020 toward the support element 1045.

[0159] The maximum extension of this screwing action can be adjusted as needed, and in the preferred embodiment disclosed herein without limiting the applicant's rights, this maximum extension is selected to be within 3 mm, as shown in Figure 13B.

[0160] In the maximum extension configuration of FIGS. 13A and 13B, the second transverse pin 1120 is located at one end of the elongated slot 1042 and the spring 1150 is at its maximum relaxed extension.

[0161] FIG. 13C is another cross-sectional view of the first stage 1040 in which the adjustment ring 1035 is threaded onto the largest portion of the outer threaded portion 1025 of the base 1020 while the extension portion 1140 of the T-shaped inner shaft 1120 protrudes deeper toward the ball shaft 1030, thus reducing the overall extension of the support 200.

[0162] In this FIG. 13C, as compared to the other FIGS. 13A and 13B, it can be seen that in the final contracted configuration, the second transverse pin 1122 abuts the opposite end of the elongated slot 1046.

[0163] 14A-14C in more detail, an alternative embodiment of the female connector 202 of the present disclosure is disclosed.

[0164] More specifically, the alternative embodiment relates to a dynamization adjustment mechanism 1412 associated with the female connector 202.

[0165] Figure 14A is a cross-sectional view of an alternative embodiment of a dynamization mechanism 1412 associated with a first stage 1440 of a female connector 202, in which parts and components having the same structure and function as the elements disclosed in Figures 10, 11, 12, and 13 above are reported with the same reference numbers.

[0166] This alternative dynamization mechanism 1412 is provided with an inner shaft 1410 made of a radiolucent alloy, such as aluminum, and secured to the support element 1045 by a first distal transverse pin 1149.

[0167] A bushing 1420 is provided around the inner shaft 1410 at the bottom of the seat that hosts the elastic element 1150. This bushing allows easy movement between the two parts 1045 and 1410. Furthermore, a first distal transverse pin 1149 is fixed on the inner shaft 1410 and slides with this shaft inside a slot 1414 provided in the sleeve support element 1045. This transverse pin 1149 is used to avoid any accidental disassembly of the strut.

[0168] A distal portion 1430 of the inner shaft 1410 is connected in shape to the interior portion of the base 1020 and presents an extension crossed by a proximal second pin 1441 that secures the shaft to the base 1020. Thus, a dynamization mechanism 1412 associated with the first stage 1440 of this female connector embodiment provides fine length adjustment of at least up to 3 mm relative to the compression of the spring 1150 and the distal cross pin 1149 that slides within the slot 1414.

[0169] Also in this embodiment, when the adjustment ring 1035 abuts against the closure collar 1046 of the support element 1045, the screwing action of the adjustment ring 1035 can be exerted on the outer threaded portion 1025 of the base 1020, thus moving the base 1020 towards the support element 1045.

[0170] The maximum extension of this screwing action can be adjusted as needed, and in the preferred embodiment disclosed herein without limiting the applicant's rights, this maximum extension is selected to be within 3 mm, as shown in Figure 14B.

[0171] FIG. 14C is another cross-sectional view of the first stage 1440 in which the adjustment ring 1035 is threaded onto the largest portion of the outer threaded portion 1025 of the base 1020 while the first distal transverse pin 1149 reaches the end of the slot 1414, compacting the base 1020 and support element 1045, thus reducing the overall extension of the strut 200.

[0172] 15A-15C, an alternative embodiment of the presently disclosed female connector 202 is disclosed. More specifically, the alternative embodiment relates to a dynamization adjustment mechanism 1512 associated with the female connector 202.

[0173] Figure 15A is a cross-sectional view of an alternative embodiment of a dynamization mechanism 1512 associated with a first stage 1540 of a female connector 202, in which parts and components having the same structure and function as the elements disclosed in Figures 10, 11, 12, and 13 above are reported with the same reference numbers.

[0174] As in the previous embodiment, the radiolucent shaft end 1010 is closed by a support element 1545 formed as a double sleeve having a main portion that is inserted into the shaft end 1010, a collar 1546 that abuts the shaft end, and a protruding portion 1574 that slidably supports the internal portion of the base 1520 of the first stage 1540.

[0175] This alternative dynamization mechanism 1512 is provided with an inner shaft 1510 made from a radiolucent alloy, for example, aluminum.

[0176] The inner shaft 1510 has one end 1530 with a threaded portion that is fixed to the base 1020 of the first stage 1540 .

[0177] On the opposite distal end 1570 of the inner shaft 1510 is a slot 1542 axially aligned along the longitudinal extension of the shaft 1510 .

[0178] The main portion of the support element 1545 has a transverse pin 1548 that passes through a slot 1542 in the inner shaft near its distal end. The transverse pin 1548 is guided along the slot 1542 during dynamization adjustment.

[0179] A collar 1560 is formed at a predetermined distance from the inner shaft end 1570 for supporting a resilient element or spring 1550 trapped between such collar 1560 and the transverse pin 1548 .

[0180] As can be seen from the example of Figure 15C, when the base 1520 of the first stage 1540 is fully retracted and hits the collar 1546 of the support element 1545, the pin 1548 is located at one end of the slot 1542 and the spring 1550 is compressed.

[0181] The dynamization mechanism of Figures 15A, 15B, and 15C is provided with an aluminum inner shaft that is fixed to the final female stage of the support column through the first stage 1560. An elastic element is housed in the distal main part of the plastic support sleeve 1545, thus making it possible to obtain a stronger plastic sleeve by increasing the material in critical areas. This construction and arrangement helps to keep the parts in the axis and avoids any possible accidental bending.

[0182] Additionally, to avoid any accidental disassembly of the strut, the transverse pin 1548 is used as a mechanical stop for the compression of the spring 1550 .

[0183] The above disclosed embodiments in their different configurations have in common the great advantage of providing a support that is easy for the surgeon to use and very practical for transport in a sterile package.

[0184] The use of reinforced plastic materials for the connectors and telescopic shafts 210 and 220 allows for a reduction in the overall weight of the strut, resulting in a lighter structure compared to other similar devices of the heavy prior art.

[0185] It will be understood that the specific embodiments described herein are shown by way of example and not as limitations of the disclosure. The principal features of the disclosure can be used in various embodiments without departing from the scope of the disclosure. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific techniques described herein. Such equivalents are considered to be within the scope of the disclosure and are encompassed by the claims.

[0186] The use of the word "a" or "an," when used in conjunction with the word "comprising" in the claims and / or specification, can mean "one," but also "one or more," "at least one," and "one or more than one." Although the present disclosure supports definitions that refer only to alternatives and "and / or," the use of the term "or" in the claims will be used to mean "and / or" unless it is expressly stated that only alternatives are referred to or the alternatives are not mutually exclusive. Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for the device and the methods described above are used to determine the value, i.e., the inherent variation in the research question.

[0187] As used in this specification and the claims, the words "comprising" (and any form of "comprising," such as "comprise" and "comprises"), "having" (and any form of "having," such as "have" and "has"), "including" (and any form of "including," such as "includes" and "include"), or "containing" (and any form of "containing," such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

Claims

1. An improved external fixation strut (200), said strut (200) comprising: an elongate body comprising a first hollow tubular shaft (210) and a second hollow tubular shaft (220); two connectors (201; 202) respectively connected to the ends of the first hollow tubular shaft (210) or the second hollow tubular shaft (220), each connector (201; 202) including a ball joint; a clamping element provided near the overlapping ends of the first hollow tubular shaft (210) and the second hollow tubular shaft (220) to provide a quick gripping action to stop telescopic sliding between the first hollow tubular shaft (210) and the second hollow tubular shaft (220), the clamping element being a clamping band (204); a manually operated fixation element acting on the clamping element to perform the rapid gripping action, the manually operated fixation element being a threaded connector; Equipped with the first hollow tubular shaft (210) has an inner diameter slightly larger than an outer diameter of the second hollow tubular shaft (220) for slidably and telescopically receiving the second hollow tubular shaft (220) therein; the first hollow tubular shaft (210) and the second hollow tubular shaft (220) of the strut (200) are made of a radiolucent synthetic plastic material; The strut (200) further comprises a sleeve (230) disposed around the portion of the strut (200) where the first hollow tubular shaft (210) and the second hollow tubular shaft (220) overlap; the clamp band (204) is positioned around the sleeve and includes oppositely facing gripping portions (205; 206), the gripping portions (205; 206) being connected by the threaded connector; An improved external fixation strut (200) comprising:

2. the threaded connector is a clamping bolt (260), the clamping bolt (260) being received through a through-hole (211) in the gripping portion (205, 206) and in a threaded nut (207); 10. The improved external fixator strut (200) of claim 1.

3. The clamping bolt (260) has a head (261) that is connected to a removable manual butterfly wrench (250).

3. The improved external fixation device (200) of claim 2.

4. The sleeve (230) is structured with a first sleeve portion (225) having an inner diameter substantially corresponding to the outer diameter of the first hollow tubular shaft (210) and a second sleeve portion (235) having an inner diameter substantially corresponding to the outer diameter of the second hollow tubular shaft (220), and the clamp band (204) is positioned around the second sleeve portion (235).

3. The improved external fixator strut (200) of claim 2.

5. A fastening system (500) comprising at least a first fastening ring (510) or fastening arch and a second fastening ring (520) or fastening arch interconnected by at least some fastening struts (200), At least one of the fixed struts is a fixed strut according to claim 1. A fastening system (500).

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