Improved external fixation strut

Abstract

To provide a new fixator structure having functional and structural features for an external fixator.SOLUTION: An external fixation strut 200 comprises: an elongated body comprising first and second hollow tubular shafts 210, 220; opposite connectors 201, 202 respectively coupled to an end portion of the first or the second shaft and each including a ball and socket joint; one shaft having an internal diameter that is slightly larger than the external diameter of the other shaft to host internally the other shaft in a slidably and telescopic manner; and the first and second shafts of the strut realized by a synthetic radiolucent plastic material.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an improved structure for an external fixation system and apparatus, and more particularly to an improved external fixation strut.

Background Art

[0002] The present invention is described with respect to an external fixation device, and more particularly, connection struts and rods. Generally speaking, external fixation devices are commonly used in various surgical procedures such as limb fractures, limb lengthening, and deformity correction. The above methods involve a rigid framework with several rings or arches arranged around the limb externally, and the several rings or arches are attached to the bone segments using wires and half-pins inserted into the bone segments and are connected to the relevant parts of the above external rigid framework.

[0003] The rings of the above rigid framework that are positioned opposite to each other are interconnected by either threaded and / or telescopic rods, either directly or together with a uniplanar hinge or a multiplanar hinge, whereby a surgeon can adjust the positions of the rings relative to each other longitudinally, rotationally, horizontally, or in terms of angle over a period of time.

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

[0005] In the case of limb lengthening, the opposing rings are directly interconnected by at least three or four threaded or telescopic rods, the length of which is regularly adjusted and which allow the gradual separation of the bone segments in the longitudinal direction.

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

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

[0008] [Prior Art] One common type of 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. In the case of correcting angular deformities, opposing rings of the Ilizarov device are connected by a pair of hinges that provide an axis of rotation to the bone segments and an angular distractor that gradually pushes the two rings and the associated bone segments apart.

[0009] Another common external fixation device is the Taylor Spatial Frame, a six - legged external fixation device based on the so - called Stewart platform, which shares many elements and features with the Ilizarov device.

[0010] The Taylor Spatial Frame comprises two external fixation rings that are attached to bone segments by wires and half pins and are connected together by five or six telescoping struts to multi - planar hinges located at both ends of the struts. Each strut can be lengthened or shortened as needed to pull the two interconnected ring segments towards each other or push them apart.

[0011] Each strut of the Taylor Spatial Frame has a threaded rod partially disposed inside a hollow shaft, and the hollow shaft includes an adjustment nut that mates with the threaded rod. However, performing rapid or slow strut length adjustment with respect to the length of the strut is time - consuming, and it is often necessary to replace the strut with a longer one during treatment.

[0012] Furthermore, without using an external support or other stabilization mechanism to support the rest of the frame, it would be impossible to replace or remove a strut from the Taylor Spatial Frame during the course of treatment. This is because if one strut is removed from the frame, it becomes unstable and collapses.

[0013] Other examples of this type of fixation device are commercially known as TrueLok and Sheffield, the latter of which is shown in Figure 1 with reference numeral 100.

[0014] These solutions are often used to address bone trauma situations where it is very important for the surgeon to quickly reduce the fracture and check the results of the reduction using x-ray radiography.

[0015] Both of the above-described products enable the attachment of struts that have the ability to be quickly connected to rings that are configured to quickly free the second ring with respect to the first ring. This simple attachment system enables the fracture to be reduced and stabilized in a relatively short time, and further enables the adjustment of the relative inclination between the rings.

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

[0017] First, the struts are obstacles in any x-ray image and often obscure the visibility of the fracture for the surgeon.

[0018] Second, while the attachment is relatively simple, the above-known solutions require a relatively long time to assemble and place on the patient. This is also because the struts have a substantial weight that makes their application to the patient uncomfortable.

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

[0020] External fixation devices based on the prior art are disclosed, for example, in U.S. Patent Application Publication No. 2016 / 199099, which is a prior art document, and Chinese Patent Application Publication No. 103494634.

[0021] The technical problem underlying the present invention is to provide a new support for an external fixation device and a new structure of a fixation device having functional and structural features that overcome the drawbacks affecting the prior art solution methods.

[0022] The main objective of the improved external fixation support of the present disclosure is to improve the visibility of the fracture site for the surgeon while allowing easy axial movement of the support for possible micrometric dynamization in micrometer units. Summary of the Invention

[0023] The idea of the solution underlying the present disclosure is to realize the main part of a ring that connects a plurality of supports with a radiation - permeable material that utilizes a joint part to receive micrometric regulation of the length of the support.

[0024] According to such an idea of the solution, the technical problem underlying the invention is solved by an improved external fixation support having the following elements. An elongate body having first and second hollow tubular shafts, Opposite connectors respectively connected to the ends of the first or second shaft, each connector including a ball joint, One shaft has an inner diameter slightly larger than the outer diameter of the other shaft to slidably and telescopically receive the other shaft inside. The first and second shafts of the support column are realized by a radiation - transmissive synthetic plastic material. Clamp elements provided near the overlapping ends of the first and second shafts to provide a fast gripping action that stops the telescopic sliding of one shaft inside the other shaft. A manually - operated fixing element that acts on the clamp element to perform the above - mentioned fast gripping action.

[0025] Various embodiments of an improved external fixation support column are included in the present disclosure. In one embodiment, the external fixation support column includes the following elements. A sleeve provided around the central portion of the support column where the first and second shafts overlap. A clamp band that is located around the above - mentioned sleeve and includes opposing gripping portions, at least one of which has a threaded central hole for receiving the threaded shaft of a tightening bolt, and the above - mentioned tightening bolt has a head connected to a removable manual operation key.

[0026] Also, various embodiments for a fixation system including at least first and second fixation rings and / or at least fixation arches interconnected by several fixation support columns are included in the present disclosure, where at least one of the fixation support columns comprises the following elements. An elongate body comprising first and second hollow tubular shafts. Connectors on both sides respectively connected to the ends of the first or second shaft, each connector including a ball 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 internally, The first and second shafts of the above-mentioned struts realized by a radiation-transparent synthetic plastic material, A clamp element provided near the overlapping ends of the first and second shafts to provide a fast gripping action to stop the telescopic sliding of one shaft inside the other shaft, A manually operated fixing element that acts on the clamp element to perform the above-mentioned fast gripping action, A sleeve provided around the central portion of the above-mentioned strut where the first and second shafts overlap, A clamp band located around the above-mentioned sleeve and including opposing and facing gripping portions, wherein the above-mentioned gripping portions are connected by a threaded connector.

[0027] Furthermore, in the above-mentioned fixing system, each strut includes a male connector and a female connector that are opposing and that each include a ball joint that enables angular movement of the corresponding strut at a spherical angle of at least 90° for folding the above-mentioned fixing system for packaging and transportation purposes.

Brief Description of the Drawings

[0028] To more fully understand the features and advantages of the present disclosure, reference is now made to the detailed description of the present disclosure in conjunction with the following accompanying drawings.

[0029]

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DETAILED DESCRIPTION OF THE INVENTION

[0030] While the manufacture and use of various embodiments of the present disclosure are discussed below, it should be recognized 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 particular ways of making and using the present disclosure and do not define the scope of the present disclosure.

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

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

[0033] The strut 200 has a main elongated body formed by a pair of coaxial hollow tubular shafts 210 and 220. In embodiments of the present disclosure, these shafts have a cylindrical shape, although other shapes are also possible.

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

[0035] The dimensional relationship between the first shaft 210 and the second shaft 220 gives the strut 200 an ensemble a telescopic configuration such that the length can be adjusted according to the need to keep the interconnected rings in a predetermined relative spatial relationship.

[0036] The shafts 201 and 220 of the strut 200 are realized by a radiation - transmissive, i.e., X - ray - passing synthetic plastic material.

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

[0038] The sleeve 230 is provided around the central portion of the strut 200 where the first shaft 210 and the second shaft overlap, or, more preferably, near the overlapping ends of the first and second shafts.

[0039] This sleeve 230 presents a recess that hosts a clamp band 204 having gripping portions 205, 206 that face each other and that can be brought closer to each other by the operation of a removable manual key 250, for example, a butterfly key.

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

[0041] The tightening of the tightening bolt 260 within the threaded nut 207 draws the gripping portions 205, 206 closer to each other. The head 261 of the tightening bolt 260 is connected to a removable manual operation key 250.

[0042] More specifically, the manual key 250 described above may be structured as a knob or a butterfly wrench that can manually operate a tightening bolt that brings one of the two parts 205, 206 closer to the other. The threaded shaft 215 is part of a bolt 260 having a recessed head, and the manual key 25 is mechanically connected to such a 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 that slides inside the other shaft 210, and thus adjust the axial main extension of the support column 200. This operation is performed by manually and quickly pre-closing the telescopic stroke of the support column 200.

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

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

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

[0047] The adjustment mechanism 212 can be considered an on-off dynamization section that allows a surgeon to pass from a rigid strut to an elastic strut having an axis of at least 3 mm without moving under load. Dynamization is achieved by a deformable element, such as an elastic element like a spring housed inside the end portion of the shaft, particularly inside the female connector. Two alternative embodiments of the dynamization mechanism 212 will be disclosed later.

[0048] FIG. 2A shows a perspective view of the components of the external fixation strut 200 of the present disclosure. More specifically, this component is a sleeve 230 provided 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 substantially corresponds to the outer diameter of the first shaft 210 and a second sleeve portion 235 having an inner diameter that substantially corresponds 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 particularly, the second sleeve portion comprises two opposed semi-tubular wings 227, 237 that project from the first sleeve portion 225 and are separated from each other by an air gap 229. In that regard, the second sleeve portion 235 appears to be longitudinally open along the opposed air gaps 229 and substantially forms a second sleeve portion 235 having a smaller diameter when compared to the diameter of the first sleeve portion 225. For this purpose, the two tubular wings 227, 237 have inner surfaces facing each other.

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

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

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

[0056] The second shaft 220 has an inner end 245 facing 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 to be the end of the stroke.

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

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

[0059] When 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 tightening operation performed by the tightening band 204. This tightening operation performs a rapid gripping action that stops the telescopic sliding of the second shaft 220 inside the first shaft 210.

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

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

[0062] The clamping band 204 is received and provided in the recessed portion of the second sleeve portion 235 with its facing gripping portions 205, 206 protruding laterally from the sleeve portion 230.

[0063] The threaded nut 207 received within the seat on the gripping portion 205 receives the threaded shaft 215 of the tightening bolt 260 having a polygonal head, for example, a hexagonal head.

[0064] The butterfly wrench 250 is laid over the head portion of the bolt 260 with the protruding flange 270 regularly arranged in a polygonal layout substantially corresponding to the faces of the polygonal head of the bolt 260.

[0065] Of course, another configuration may be adopted. For example, the wrench 250 may be structured to have a polygonal hole that fits or is put on the polygonal head of the tightening bolt 260.

[0066] That is, the butterfly wrench 250 is a user adaptor for the tightening bolt 260 that enables the user to perform a gripping operation that is a manually performed gripping operation more quickly and strongly, and that brings one of the two portions 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 axial relative movement of one shaft sliding within the other shaft, and thus adjust the axial main extension of the support 200.

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

[0069] In this figure, the tightening bolt 260 and the corresponding threaded nut 207 for tightening the gripping portions 205, 206 are shown in a disassembled state. Accordingly, the aligned threaded holes 211 of the gripping portions can be clearly visualized. The holes of the gripping portion 205 are enlarged at a seat intended to accommodate the threaded nut 207.

[0070] Figure 4 shows a schematic perspective view of the disclosed external fixation strut 200 with the butterfly wrench 250 removed after a manual closing operation performed prior to the telescopic stroke of the strut 200 without the need to access an external key. This is to reduce the time and complexity of the operation. Finally, the above wrench 250 is manually removed and definitive locking is done with the aid of a key.

[0071] Without the butterfly wrench 250, the above bolt head is exposed and the configuration employed can be tightened using a key.

[0072] Figure 5 is a perspective view of one embodiment of an external fixation system 500 including the strut 200 realized based on the present disclosure.

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

[0074] The fixing rings 510 and 520 are interconnected through several fixing struts 200, for example, at least three or four struts, as described above. However, it does not prevent the adoption of a system configuration including a large number of struts, for example, six.

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

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

[0077] Preferably, the strut 200 is connected to the rings 510 and 520 through the opposite connectors 201 and 202 on both sides, that is, the male connector 201 and the female connector 202.

[0078] The above connectors cooperate with holes (not shown) regularly provided along the above rings or arches and are fixed to the above rings or arches through fixing bolts 530.

[0079] To enable angular movement of the corresponding struts at a spherical angle of at least 90° and an operating angle of at least 45°, each connector is further associated with a ball joint.

[0080] The freedom of the connectors 201 and 202 with respect to the angle enables the fixing system 500 to be folded for packaging and transportation purposes.

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

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

[0083] The struts 200 shown in this figure do not present a butterfly wrench 250. That is, the telescopic length of the struts 200 has already been adjusted, and the adoption of the ball joints 201 and 202 at both ends enables the overall structure to be folded in the direction of the curved arrow 650 to obtain a substantially flat configuration of the fixation system 600.

[0084] Thus, thanks to the possibility provided by the angle of the ball joints up to a maximum of 90°, it is possible to pre-assemble a fixation system including at least two rings and two to four struts that are already assembled and folded. This configuration is supplied in a sterile package with a reduced size.

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

[0086] The connecting elements 201 and 202 can be angled up to a maximum of 90°, and as shown in FIG. 6B, it is possible to lead the two rings 510 and 520 substantially onto the same plane together with the connected struts 200.

[0087] Thanks to the larger slots on the connecting elements described in detail later, angling to 90° can be achieved at both the female and male ends. The other slots remain the same as those of the current strut.

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

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

[0090] Figure 7B shows another cross-sectional view of the external fixation strut of the present disclosure from the opposite perspective.

[0091] In this Figure 7B, the gripping portion 205 cut across by the threaded shaft 205 of the tightening bolt can be clearly visualized.

[0092] The dynamization mechanism 212 is associated with the female connector 202. However, an alternative embodiment where the above dynamization mechanism is associated with the male connector 201 in a reversed manner cannot be excluded.

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

[0094] More specifically, the male connector 201 is associated with one free end 810 of the second shaft 220 and includes a set of stages 840 and 850 that are mechanically connected in a sequence. The first stage 840 is an interconnecting stage for the ball joint stage 850 that brings the threaded rod 280 of the male connector 201.

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

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

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

[0098]

[0099] The second stage 850 includes a ball 855 for the ball joint, where the ball cage 848 represents the socket described above and a threaded rod 280 integrally formed with the ball 855.

[0100]

[0101] A more protruding portion of this threaded rod 280 represents a male connection for one or the other of the fixing rings 510, 520 of the fixing system 500. More specifically, the threaded rod 280 may be inserted into one of a plurality of holes typically provided in the fixing ring and fixed by a tightening bolt 530. A special closing cap 890 is attached to the threaded rod 280 to close the socket portion of the ball joint formed by the ball cage 848 and the ball 855.This special closing cap 890 is formed by two cylindrical portions having different diameters. A first higher or thicker portion 870 has a set of opposing flat surfaces 860 to allow the insertion of an operating key (not shown).

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

[0103] The second smaller portion 880 of the closing cap 890 has a larger diameter and a knurled or milled surface 885 to allow manual rotation by the 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 as the elements disclosed in FIG. 8 carry the same reference numerals.

[0105] FIG. 9 is a schematic perspective view of a cross-section of the male connector 201 already disclosed with respect to FIG. 8.

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

[0107] This shaft end element 940 has a first portion 942 on the end 810 of the second shaft, which is in particular press-fitted or fixed internally to such an end. A second intermediate portion 944 wraps the end 810 as a surrounding collar, while a third extension portion 946 is provided for interconnecting with the support element of the interconnection stage 840.

[0108] The second intermediate portion 944 corresponds to the base 830 shown in FIG. 8.

[0109] Furthermore, the extension portion 940 is externally threaded and provides a passing hole 948 for hosting a rod 842 that supports the 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 screwed into the intermediate portion 944 at the end of the stroke, i.e., the externally threaded portion of the extension 946 adjacent to the base 830.

[0112] However, the screwing operation of the support element 845 can be adjusted to obtain a controlled axial movement of the entire support column 200 in micrometer units when attached to the opposing fixed rings 510, 520.

[0113] In other words, by operating on 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 column 200 can be very precisely controlled when attached between the two rings 510, 520.

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

[0115] The ball 855 is formed in one-piece construction with a threaded rod 280 that also exhibits a diameter 960 expanded closer to the ball 855 and is provided with an externally threaded surface 965.

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

[0117] From the cross-section of FIG. 9, the inner portion of the closure cap 890 has a hemispherical shape 970, which defines a sort of closure of the ball cage 848 and, together with the ball cage 848, defines a spherical chamber in which the ball 855 of the ball joint moves angularly.

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

[0119] More specifically, the female connector 202 is associated with one free end 1010 of a first shaft 210 and comprises a set of stages 1040 and 1050 that are mechanically connected in a sequence. The first stage 1040 is a joint stage for the last stage 1050 that includes a female element 1060 (joint stage).

[0120] The first joint 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 connected to the base 1020 of the ball joint 1030.

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

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

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

[0124] The ball joint 1030 protruding from the base 1020 has a plurality of regularly spaced openings 1037, for example four openings. One of these openings 1033 is larger than the other openings 1037.

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

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

[0127] FIG. 11A shows a cross-sectional perspective view of the same female connector 202 of FIG. 10 and shows in more detail the already described adjustment mechanism 212 which allows for independent, rapid and progressive fine adjustment of the entire length of the support 200.

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

[0129] From this cross-sectional view, it is recognized that the ball joint 1030 projects 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 has a T-shaped inner shaft 1125 that slides within a hole 1135 of the support element 1045, and presents a passing hole 1110 for hosting a pin 1120 having an expansion portion 140 that slides along a passing hole 1110.

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

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

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

[0134] The T-shaped inner shaft 1120 is advantageously realized by a component of a radiation-transparent material, such as aluminum, or alternatively, a reinforced plastic material.

[0135] The elastic element 1150 is provided inside the support element 1045. More specifically, the spring 1150 is wound around the handle portion 1125 of the inner shaft 1120 inside the support element 1045 in order to exert an elastic action in cooperation with the screwing action of the threaded adjustment ring 1035 on the threaded portion 1025 outside the base 1020.

[0136] The second transverse pin 1142 is fixed at the base 1020 and crosses the extended portion 1140 of the T-shaped inner shaft 1120. This second transverse pin 1142 is slidable inside an elongated slot 1122, similar to a button hole, formed centrally in the T-shaped inner shaft 1120 and arranged along the main axis of the T-shaped inner shaft 1120. The relative movement between the support element 1045 and the base 1020 of the first stage 1040 is accompanied by a corresponding relative movement of the second transverse pin 1142 inside the elongated slot 1122.

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

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

[0139] The threaded adjustment ring 1035 can be manually operated 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 leaf spring 1150. In this way, it enables a smooth, independent, rapid, progressive and fine adjustment of the overall length of the strut 200 through this adjustment mechanism 212.

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

[0141] The structure of the female connector 202 is completed by a spring-loaded mechanism 1100 provided around the female element 1060 at the last stage 1050.

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

[0143] The rod 1160 has a distal portion 1195 threaded to be screwed into a corresponding seat provided at the ball joint 1030.

[0144] The spring-loaded mechanism 1100 includes a spring 1111 hosted inside the first tubular chamber 1180 and surrounding a more proximal portion of the rod 1160 in which the female element 1060 is formed.

[0145] The rod 1160 extends through the opening 1133 of the ball joint 1030, which communicates with a larger opening 1033 of the ball joint 1030 that enables rotation of the ball joint 1030 around at least 90° within the last stage 1050 including the proximal cylindrical portion 1090 of the female element 1060.

[0146] By manually operating the extended 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 described above can be adjusted, thus adjusting the relative spacing between the last stage 1050 and the first stage 1040. This enables reaching the 90° "foldable" configuration of the connector 202, which is different from the working configuration where the angular movement between the first and last stages 1040, 1050 is in the range of 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 carry the same reference numerals as in FIG. 11A.

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

[0150] The threaded adjustment ring 1035 is shown at a position closer to the base 1020, where a clearance is provided with respect to the end 1010 of the shaft 210 in a state where the spring 1150 is released.

[0151] The larger opening 1033 of the ball joint 1030 is also shown in comparison to the one on the opposite side of the smaller opening 1037.

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

[0153] Figure 12B is a perspective view of the female connector of Figure 10, in which an internal spring biasing mechanism 1100 including a spring 1111 wound around the rod 1160 is visible.

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

[0155] Figure 12C is a slightly enlarged cross-sectional view of the female connector of Figure 12B, more specifically, of the distal threaded portion 1195 of the rod 1160 screwed into the seat provided in the ball joint 1030, at the end where it can be clearly seen, at the last stage 1050.

[0156] Rotation of the annular ferrule 1080 adjusts the cohesion between the last stage 1050 and the first stage 1040 including the ball joint 1030, and enables the last stage 1050 to be rotated towards a larger angular movement in order to reach a 90° "foldable" configuration.

[0157] Figure 13A shows a cross-sectional view of the first stage 1040 of the female connector 202 and an adjustment mechanism 212 that enables independent, rapid, progressive, and fine adjustment of the length of the support 200.

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

[0159] The maximum extension of this screwing action can be adjusted as required. In the preferred embodiments disclosed herein without limiting the applicant's rights, this maximum extension is selected within 3 mm, as shown in FIG. 13B.

[0160] In the configuration of the maximum extension 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 screwed onto the largest part of the threaded portion 1025 outside the base 1020 while the extended portion 1140 of the T-shaped inner shaft 1120 protrudes deeper towards the ball shaft 1030, thus reducing the overall extension of the support column 200.

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

[0163] Now, referring more particularly to FIGS. 14A - 14C, an alternative embodiment of the female connector 202 of the present disclosure is disclosed.

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

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

[0166] This alternative dynamization mechanism 1412 is provided with an internal shaft 1410 made of a radiation-transparent alloy, such as aluminum, which is fixed to the support element 1045 by a first distal transverse pin 1149.

[0167] A bushing 1420 is provided around the internal shaft 1410 at the bottom of the seat for receiving the elastic element 1150. This bushing allows for easy movement between the two parts 1045 and 1410. Further, the first distal transverse pin 1149 is fixed to the internal shaft 1410 and slides with this shaft inside a slot 1414 provided in the sleeve support element 1045. This transverse pin 1194 is used to avoid any accidental disassembly of the strut.

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

[0169] Also in this embodiment, when the adjustment ring 1035 abuts against the closing collar 1046 of the support element 1045, the screwing action of the adjustment ring 1035 can be exerted on the threaded portion 1025 outside the base 1020, and thus, the base 1020 can be moved toward the support element 1045.

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

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

[0172] Now, referring more specifically to FIGS. 15A - 15C, an alternative embodiment of the female connector 202 of the present disclosure is disclosed. More specifically, the alternative embodiment relates to the dynamicization adjustment mechanism 1512 associated with the female connector 202.

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

[0174] As in the previous embodiment, the radiation - transparent shaft end 1010 is closed by a support element 1545 formed as a double sleeve having a main portion inserted into the shaft end 1010, a collar 1546 abutting against the shaft end, and a protruding portion 1574 slidably supporting an inner portion within the base 1520 of the first stage 1540.

[0175] This alternative dynamization mechanism 1512 is provided with a radiation - transparent alloy, for example, an inner shaft 1510 made of aluminum.

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

[0177] On the distal end 1570 of the inner shaft 1510 opposite the above, there are slots 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 passing through a slot 1542 provided near the distal end of the inner shaft. The transverse pin 1548 is guided along the slot 1542 during dynamization adjustment.

[0179] A collar 1560 is formed at a predetermined interval from the inner shaft end 1570 to support an elastic element, i.e., a spring 1550, trapped between such a collar 1560 and the transverse pin 1548.

[0180] As can be recognized by the example of FIG. 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] In the dynamization mechanisms of FIGS. 15A, 15B, and 15C, an aluminum inner shaft is provided that is fixed to the final female stage of the strut through a first stage 1560. The elastic element is housed in the distal major portion of a plastic support sleeve 1545, thus allowing for a stronger plastic sleeve due to the increased material in the critical area. This construction and configuration helps to maintain the components within the axis and avoid any accidental bending that may occur.

[0182] Furthermore, 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 embodiments disclosed above with their different structures have the common great advantage of providing struts that are easy to use for the surgeon and very practical for transport in a sterile package.

[0184] The use of a reinforced plastic material for the connectors and the telescopic shafts 210 and 220 makes it possible to reduce the weight of the entire strut, resulting in a lighter structure compared to other similar devices of the prior art.

[0185] It is understood that the specific embodiments described herein are shown by way of example and are not intended to limit the present disclosure. The main features of the present disclosure can be used in various embodiments without departing from the scope of the present disclosure. One of ordinary skill in the art can recognize or confirm a number of equivalents equivalent to the specific methods described herein using only routine experimentation. Such equivalents are considered to be within the scope of the present disclosure and are included in the claims.

[0186] The use of the words "a" or "an", when used in the claims and / or the specification in conjunction with the term "comprising", can mean "one", but is also consistent with the meaning of "one or more", "at least one", and "one or more than one". Although this disclosure supports only alternatives and definitions that refer to "and / or", the use of the term "or" in the claims is used to mean "and / or" unless it is clear that only alternatives are being referred to or the alternatives are mutually exclusive. Throughout this application, the term "about" is used to indicate that a value includes the variation of the inherent error of the device, and the above method is used to determine the value, i.e., the variation that exists in the research problem.

[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

Claim 1 An improved external fixation strut (200), wherein the strut (200) comprises: An elongate body comprising a first hollow tubular shaft (210) and a second hollow tubular shaft (220); Connectors (201; 202) on both sides respectively connected to the ends of the first shaft (210) or the second shaft (220), each connector (201; 202) including a ball joint; One shaft (220) having an inner diameter slightly larger than the outer diameter of the other shaft (210) for slidably and telescopically receiving the other shaft (210) therein; The first and second shafts (210; 220) of the strut (200) realized by a radiation - transmissive synthetic plastic material; Clamp elements provided near the overlapping ends of the first and second shafts (210; 220) to provide a quick gripping action to stop the telescopic sliding of one shaft (210) inside the other shaft (220); A manually operated fixing element acting on the clamp element to perform the quick gripping action; Comprising Each of the ball joints is structured to allow angular movement of the corresponding connector (201; 202) at a spherical angle of at least 90°; An improved external fixation strut (200), characterized in that.

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