CN115484883A

CN115484883A - Improved external fixation strut

Info

Publication number: CN115484883A
Application number: CN202180015839.0A
Authority: CN
Inventors: 达妮埃莱·文图里尼; 安德列·奥托博尼; 詹卢卡·米兰; 约翰·大卫·小罗斯; 凯伦·迪维塔·斯坦德费尔; 米哈伊尔·山姆库克; 亚历山大·切尔卡申
Original assignee: Orthofix SRL; Texas Scottish Rite Hospital for Children
Current assignee: Orthofix SRL; Texas Scottish Rite Hospital for Children
Priority date: 2020-03-23
Filing date: 2021-03-18
Publication date: 2022-12-16
Also published as: WO2021191046A1; ZA202209053B; BR112022018952A2; CO2022012371A2; JP2023523388A; IL295416A

Abstract

The present disclosure relates to an improved external fixation strut comprising: an elongate body comprising first and second hollow tubular shafts; opposite connectors coupled to ends of the first or second shaft, respectively, and each including a ball joint; a shaft having an inner diameter slightly larger than an outer diameter of the other shaft to receive the other shaft inside in a slidably telescopic manner; the first and second axes of the strut are realized in a synthetic radiolucent plastic material; a clamping element disposed adjacent the overlapping ends of the first and second shafts for providing a quick clamping action to resist telescoping sliding of one shaft within the other; a manually operated fixing element acting on the clamping element for exerting said rapid clamping action; a sleeve disposed around a central portion of the leg where the first and second shafts overlap; and a clamping band surrounding the sleeve and including opposing and facing clamping portions connected by a threaded connection. Also disclosed is a fixation system comprising at least a first and a second fixation ring and/or at least one fixation arch interconnected by at least one of the above-mentioned fixation struts.

Description

Improved external fixing support

Background

The present disclosure relates to an improved structure for external fixation systems and devices, and more particularly, to an improved external fixation strut.

The invention is described in connection with external fixation devices, particularly connecting struts and rods. Generally, external fixation devices are commonly used in a variety of surgical procedures, including limb fractures, limb lengthening, and deformity correction. The process involves a rigid frame comprising several rings or arches placed externally around the limb and attached to the bone segments using wires and half-needles (half pins) inserted into the bone segments and connected to the relevant part of the external rigid frame.

The rings of the rigid frame, which are opposite each other, are interconnected directly or in combination with single or multi-plane hinges by means of threads and/or telescopic rods, which enable the surgeon to adjust the position of the rings relative to each other longitudinally, rotationally, horizontally or angularly over a period of time.

For example, in limb lengthening, the bone is surgically divided into two sections, and wires and half-needles are inserted into the bone sections above and below the bone surgical incision and attached to loops of a rigid frame interconnected by struts or telescopic connecting rods.

For limb lengthening, the opposed rings are directly interconnected by at least three or four threaded or telescoping rods whose length is periodically adjusted and gradual longitudinal separation of the bone segments is achieved.

The rigid frame is used to gradually longitudinally separate the two bone segments over a period of time (e.g., one millimeter per day). This achieves that bone is gradually formed in the gap between the bone segments created by this separation technique. Once the desired amount of lengthening is reached (e.g., 5-6 cm), the external device is stabilized to a fixed position and left on the bone segments until the newly formed bone is fully mineralized (e.g., 3-6 months, depending on the nature of the pathology and the amount of lengthening).

Similarly, in deformity correction, the bone (usually at the apex of the deformity) is surgically divided into two segments, and then wires and half-needles are inserted into the bone segments above and below the bone surgical incision and attached to the rings of the rigid frame. In this case, the opposing rings of the rigid frame are also connected together by a threaded rod with an attached hinge and an angular distractor for gradually angularly separating the two bone segments over a period of time.

Prior Art

One common fixation device is a round metal structure known as the Ilizarov device. The Ilizarov device, when used for limb lengthening or deformity correction, consists of several rings or arches that are placed externally around the limb and attached to surgically separated bone segments using wires and half-needles. For correction of angular deformities, 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 gradually separates the two rings and associated bone segments.

Another common external fixation device is known as the Taylor Spatial Frame, a hexapod type external fixation device based on the so-called Stewart platform, but with many of the components and features of the Ilizarov device.

The taylor space bracket includes two external fixation rings attached to the bony segment by wires and half-pins and connected together by five or six telescoping struts with multi-planar hinges at both ends of the struts. Each strut may be lengthened or shortened as necessary to pull the two interconnected ring segments toward each other or push them apart.

Each post of the taylor space bracket has a threaded rod partially disposed inside a hollow shaft that includes an adjustment nut that mates with the threaded rod. However, rapid or gradual adjustment of the strut length is time consuming and often requires replacement of the strut with a longer strut during treatment.

Furthermore, if external bracing or other stabilizing mechanisms are not used to support the rest of the frame, it is not possible to replace or remove the struts of the taylor space stent during treatment, because if one strut is removed from the frame, the frame will become unstable and will collapse.

Other examples of such fixtures are commercially known as TrueLok and Sheffield, the last of which is shown in fig. 1, reference numeral 100.

These solutions are often used to address bone trauma situations, and it is important for the surgeon to reduce the fracture quickly and to check the reduction results radiographically.

Both of the above products allow the installation of a post that can be quickly connected to the corresponding ring, thus quickly releasing the second ring with respect to the first. This simple mounting system allows the fracture to be restored and stabilized in a relatively short time and further achieves a relative inclination between the adjustment rings.

However, both types of products have some disadvantages.

First, the struts represent an obstacle in any radiograph, often hindering the surgeon's visibility of the fracture.

Secondly, although relatively easy to install, the known solutions require a relatively long time to assemble and position on the patient, also because the struts have an inherent weight, which makes the application uncomfortable on the patient.

Moreover, the transport and storage of those known external fixators is always complicated by their size and encumbrance.

External fixators according to the prior art are for example disclosed in prior art documents US2016/199099A1 and CN 103494634A.

The technical problem underlying the present invention is that of providing a new strut for an external fixator and a new fixator structure with functional and structural features to overcome the drawbacks affecting the prior art solutions.

The primary purpose of the improved external fixator struts of the present disclosure is to improve surgeon visibility of the fracture site while enabling easy axial movement of the strut to enable possible micrometric dynamisation.

Disclosure of Invention

The solution idea underlying the present disclosure is to realize the main part of the ring of interconnected struts with a radiolucent material to carry the fine tuning of the strut length with the joining part.

According to such solution concept, it is emphasized that the technical problem of the present invention is solved by an improved external fixator support comprising:

-an elongate body comprising first and second hollow tubular shafts;

-opposite connecting members coupled to the ends of the first or second shaft respectively and each comprising a ball joint;

-one shaft having an inner diameter slightly larger than the outer diameter of the other shaft to receive the other shaft inside in a slidable telescopic manner;

-the first and second axes of the strut are realized in a synthetic radiolucent plastic material;

-a clamping element, provided in the vicinity of the overlapping ends of the first and second shafts, for providing a quick clamping action to prevent telescopic sliding of one shaft inside the other shaft;

-a manually operated fixing element acting on the gripping element for applying said quick gripping action.

The present disclosure includes various embodiments of an improved external fixation strut. In one embodiment, the external fixation strut comprises:

-a sleeve arranged around a central part of the strut where the first and second shafts overlap; and

-a clamping band surrounding the sleeve and comprising opposite and facing clamping portions, wherein at least one clamping portion has a central threaded hole receiving a threaded shaft of a clamping bolt. The clamping bolt has a head coupled to a removable manually operable key.

The present disclosure also includes various embodiments for a fixation system comprising at least first and second fixation rings and/or at least fixation arches interconnected by a number of fixation struts, wherein at least one of the fixation struts comprises:

-an elongate body comprising first and second hollow tubular shafts;

-one shaft having an inner diameter slightly larger than the outer diameter of the other shaft for receiving the other shaft inside in a slidable telescopic manner;

-a manually operated fixing element acting on the gripping element for applying said quick gripping action;

-a sleeve arranged around a central part of the strut where the first and second shafts overlap;

-a clamping band surrounding the sleeve and comprising opposite and facing clamping portions connected by a threaded connection.

Furthermore, in the above-described securing system, each post comprises opposing male and female connectors, each comprising a ball-and-socket joint, such that the corresponding post undergoes angular movement through a spherical angle of up to at least 90 ° to fold the securing system for packaging and shipping purposes.

Drawings

For a more complete understanding of the features and advantages of the present disclosure, reference is now made to the detailed description of the disclosure and to the accompanying drawings, in which:

FIG. 1 is a perspective view of one embodiment of an external fixation system including a post, implemented in accordance with the prior art;

FIG. 2 is a perspective view of an embodiment of an external fixation strut of the present disclosure;

FIG. 2A is a perspective view of an assembly of external fixation struts of the present disclosure;

FIG. 2B is a cross-sectional view of the assembly shown in FIG. 2A mounted on an external fixation strut of the present disclosure;

FIG. 3 is a perspective schematic view of a central portion of a strut of the present disclosure;

FIG. 3A is a perspective view of the central portion of the external fixation strut of the present disclosure with the nut and bolt securing the clamp strap to the center sleeve removed;

FIG. 4 is another perspective view of the external fixation strut of the present disclosure in a different configuration;

FIG. 5 is a perspective view of one embodiment of an external fixation system including a post, implemented in accordance with the present disclosure;

fig. 6A is another perspective view of another embodiment of an external fixation system including at least three struts implemented according to the present disclosure;

FIG. 6B is a perspective view of the embodiment of FIG. 6A in a folded configuration;

figures 7A and 7B respectively show cross-sectional views of the external fixation strut of the present disclosure taken from opposite perspectives;

FIG. 8 is a perspective view of a male connector associated with one end of an external fixation strut of the present disclosure;

FIG. 9 is a cross-sectional view of the male coupling of FIG. 8;

FIG. 10 is a perspective view of a female connector associated with one end of an external fixation strut of the present disclosure;

FIG. 11A is a cross-sectional view of the female coupling of FIG. 10;

FIG. 11B is another cross-sectional view of the female coupling of FIG. 11A taken from a vertical perspective;

FIG. 12A is another perspective view of the female coupling of FIG. 10;

FIG. 12B is a perspective view of the female coupling of FIG. 10 with an internal spring-loaded mechanism visible therein;

FIG. 12C is a slightly enlarged cross-sectional view of the female coupling of FIG. 12B;

13A, 13B, and 13C show enlarged cross-sectional views of the female connection of the present disclosure in different configurations, respectively;

14A, 14B, and 14C show enlarged cross-sectional views of an alternative embodiment of a female connection of the present disclosure in different configurations, respectively;

fig. 15A, 15B and 15C show enlarged cross-sectional views of another embodiment of the female connector of the present disclosure in different configurations, respectively.

Detailed Description

While the making and using of various embodiments of the present disclosure are discussed in detail 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 invention, and do not delimit the scope of the present invention.

Fig. 2 shows a schematic view 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 attach to respective fixation rings or arches of an external fixator.

The ring of the external fixator to which the strut 200 is attached is shown in another figure which will be disclosed later.

The strut 200 has an elongate body formed by a pair of aligned and coaxial hollow

tubular shafts

210 and 220. In the embodiments of the present disclosure, the shafts have a cylindrical shape, but other shapes may also be employed.

In the exemplary embodiment disclosed herein, the inner diameter of the first shaft 210 is slightly larger than the outer diameter of the second shaft 220 such that the second shaft 220 is slidably received inside the first shaft 210. In other words, the second shaft 220 may slide along the lumen of the first shaft 210.

This dimensional relationship between the first shaft 210 and the second shaft 220 gives the strut 200 an overall telescopic construction that can be adjusted in length as needed to maintain the interconnecting rings in a predetermined relative spatial relationship.

The

shafts

210 and 220 of the support column 200 are realized from a radiolucent, i.e. X-ray radiolucent, synthetic plastic material.

As a possible example, these shafts may be realized in a high-tech polymeric material, for example in PEEK (polyetheretherketone). Such high-tech polymers are characterized by excellent heat resistance and chemical resistance; in addition, it has good tribological, mechanical and dielectric properties, since it supports sterilization cycles and is resistant to ionizing radiation, making it a good alternative to metallic materials. The sleeve 230 is disposed about a 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.

The sleeve 230 has a recessed portion that receives the clamping band 204 having opposed and facing clamping

portions

205, 206 that are brought into proximity with one another by action of a removable manual key 250, such as a butterfly key.

The clamping

portions

205, 206 have aligned through holes 211 through which the threaded shafts 215 of the clamping bolts 260 pass. The free end of the threaded shaft is received in a nut 207 which is arranged on the opposite side of the clamping

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 bore of one of the clamping

portions

205, 206, rather than engaging a loose nut.

Tightening the clamping bolt 260 within the nut 207 brings the clamping

portions

205, 206 closer to each other. The head 261 of the clamping bolt 260 is coupled to a removable manual operating key 250.

More specifically, said manual key 250 may be configured as a knob or a butterfly wrench, which can be manually operated for tightening a bolt, thereby forcing the two

portions

205, 206 towards each other. The threaded shaft 215 is part of a bolt 260 having a recessed head, and the manual key 250 is mechanically coupled to such a bolt 260 in a removable manner.

By acting on the thumb wrench 250, the operator can prevent the relative axial movement of one shaft 220 sliding within the other shaft 210, thereby adjusting the main axial extension of the strut 200. This action is used to manually and quickly pre-close the telescoping travel of the strut 200.

Butterfly wrench 250 is removably associated with one clamping portion 206 of the two facing clamping

portions

205, 206 and can be removed to expose a recessed head of bolt 260, which can receive and accommodate a key or fastening tool, as will be described in detail later with respect to another figure.

The external fixation strut 200 of the present disclosure has

connectors

201, 202, including ball joints associated with opposite ends thereof, and may be attached to the outer or inner surface of a fixation ring or arch. These ball

joint connectors

201, 202 are associated with the final male and

female connectors

280, 290, respectively, for faster connection to the corresponding rings of the ring holder.

At least one of these ball

joint connections

201, 202 is housed in an adjustment mechanism 212, enabling an independent, rapid and progressive fine dynamic adjustment of the length of the column 200, as we will see in the following part of the present description.

The adjustment mechanism 212 may be considered to be a switching power section that enables the surgeon to change from a rigid strut that does not move under load to a resilient strut that reaches at least 3mm axially. The dynamization is achieved by means of a deformable element, for example an elastic element, such as a spring housed in a terminal portion of the shaft, in particular a female connector. Two alternative embodiments of the dynamic mechanism 212 will be disclosed later.

Fig. 2A illustrates a perspective view of the components of the external fixation strut 200 of the present disclosure. More specifically, the component is a sleeve 230 disposed about overlapping inner ends of the first and

second shafts

210, 220.

The sleeve 230 is comprised of a first sleeve portion 225 having an inner diameter substantially corresponding to the outer diameter of the first shaft 210 and a second sleeve portion 235 having an inner diameter substantially corresponding to the outer diameter of the second shaft 220.

The first and

second sleeve portions

225 and 235 are integrally formed as a one-piece structure.

More specifically, the second sleeve portion includes two opposing

semi-tubular wings

227 and 237 projecting from the first sleeve portion 225 and spaced from each other by an air gap 229. The inner surfaces of the two

tubular wings

227, 237 face each other to substantially form a second sleeve portion 235 that appears to open longitudinally along the opposing air gap 229 and has a smaller diameter if compared to the diameter of the first sleeve portion 225.

The smaller diameter of the second sleeve portion 235 creates a radial step 232 where the second and

first sleeves

235, 225 are connected to each other.

At the free end of each tubular wing 227 and 237 a collar 228 is provided. 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 grip strip 204 is received.

Fig. 2B shows a cross-sectional view of a sleeve 230 mounted on the improved external fixation strut of the present disclosure.

As can be appreciated from this cross-sectional view, the first sleeve portion 225 is secured around and on an inner end 240 of the first shaft 210, while the other sleeve portion 235 abuts such inner end 240 in correspondence with the radial step 232.

The inner end 245 of the second shaft 220 faces the inner end 240 of the first shaft 210 and is slidable within the first shaft in a telescoping manner. The inner end 245 of the second shaft is closed by a cap 248 which can be considered the end of travel.

The grip strip 204 is received in an annular space or groove of the second sleeve 235 between the radial step 232 and the collar 228.

In this figure, one clamping portion 205 of the clamping band 204 can be seen with a nut 207 for receiving the threaded shaft of the thumb wrench 250.

When the clamping

portions

205 and 206 are brought closer by the thumb wrench 250, the clamping action performed by the clamping band 204 obtains a tightening pressure around the second sleeve 235. This clamping action performs a quick clamping action, stopping the telescopic sliding of the second shaft 220 within the first shaft 210.

FIG. 3 illustrates another perspective view of one embodiment of the external fixation strut of the present disclosure for an external ring fixation device. The central part of the outer fixing strut 200 is shown, wherein the two

shafts

210 and 220 overlap in a telescopic manner.

The sleeve portion 230 wraps around a central portion of the strut 200 where the first concentric shaft 210 and the second concentric shaft 220 overlap.

The grip strip 204 is received and arranged in a recessed portion of the second sleeve portion 235, the facing

grip portions

205, 206 of which project laterally from the sleeve portion 230.

A nut 207 received in a seat on the clamping portion 205 receives a threaded shaft 215 of a fastening bolt 260 having a polygonal head (e.g., a hexagonal head).

The butterfly wrench 250 overlaps the head of the bolt 260, and the protruding flanges 270 are regularly arranged in a polygonal layout, which substantially corresponds to the surface of the polygonal head of the bolt 260.

Obviously, other configurations may be employed. For example, wrench 250 may be configured with a polygonal bore to fit or rest on the polygonal head of fastening bolt 260.

In other words, the thumb wrench 250 is a user adjustment for tightening the bolt 260, enabling the user to apply a faster and stronger manually operated clamping action, forcing the two

parts

205, 206 towards each other by the screwing action of the bolt 260.

By acting on this butterfly wrench 250, the operator can stop the relative axial movement of one shaft sliding inside the other, thus adjusting the main axial extension of the prop 200.

Fig. 3A illustrates another perspective view of one embodiment of an external fixation strut of the present disclosure for an external ring fixation device. The central portion of the outer fixation strut 200 is shown with the two

shafts

210 and 220 overlapping in a telescoping manner.

In this figure, the fastening bolts 260 and the corresponding nuts 207 fastening the clamping

portions

205, 206 are shown in a disassembled state. The alignment through holes 211 of the clamping portion are clearly visible; the hole in the clamping portion 205 is enlarged to receive the base of the nut 207.

Fig. 4 shows a perspective schematic view of the externally fixed strut 200 of the present disclosure, wherein the thumb wrench 250 has been removed after the manual pre-closing action of the telescoping stroke of the strut 200 without accessing the outer keys. This is to reduce the time and complexity of the operation. Finally, the wrench 250 is manually removed and the final locking is done with the help of a key.

Without the thumb wrench 250, the bolt head is exposed and the configuration employed can be tightened using a key.

Fig. 5 is a perspective view of one embodiment of an external fixation system 500 including a strut 200 implemented according to the present disclosure.

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

The securing rings 510 and 520 are interconnected by some securing struts 200 as previously disclosed, for example at least three or four struts. However, a system configuration including more struts (e.g., six struts) may also be employed.

The structure of each strut 200 is as disclosed in the preceding paragraphs of the present disclosure. However, at least one strut having a different configuration may be used, as it requires a particular dynamic function of at least one strut.

In other words, the fixation system 500 may include at least one strut 200 according to the present disclosure.

Advantageously, the strut 200 is connected to the

rings

510 and 520 by means of the

opposite connectors

201, 202; namely a male connector 201 and a female connector 202.

The connectors are fitted with holes (not shown) regularly arranged along the ring or arch and fixed to the ring or arch by means of fixing bolts 530.

Each link is also associated with a ball joint to allow angular movement of the corresponding strut, with a spherical angle of at least 90 ° and an operating angle of at least 45 °.

The angular freedom of the

connectors

201 and 202 allows the fixing system 500 to be folded for packaging and transportation purposes.

Further, the system 500 may be configured in a pre-assembled configuration that is prepared in a sterile environment and packaged accordingly for later, faster use by the surgeon.

Fig. 6A illustrates a perspective view of another embodiment of an external fixation system 600 including three struts 200 implemented according to the present disclosure.

The strut 200 shown in this figure does not have a butterfly wrench 250, meaning that the telescoping length of the strut 200 has been adjusted, with the opposing ball joints 201 and 202 being used to fold the entire structure along the curved direction arrow 650 to achieve the substantially flat configuration of the binding system 600.

Thus, thanks to the angle of the ball joint up to 90 °, it is possible to preassemble a fixing system comprising at least two rings and two to four already assembled and folded struts. This configuration is provided in a reduced size sterile package.

Fig. 6B shows a perspective view of the embodiment of fig. 6A in a folded configuration.

The

coupling elements

201 and 202 achieve an angle of up to 90 ° and are able to guide the two

rings

510 and 520 with the struts 200 connected almost on the same plane, as shown in fig. 6B.

Due to the larger slots on the coupling element, which will be disclosed in detail below, a 90 ° angle can be achieved at both the male and female ends. The other slots remain the same as the current strut.

Fig. 7A shows a cross-sectional view of an external fixation strut of the present disclosure. The two

shafts

210 and 220 overlap in a telescoping manner, and

sleeve portions

225, 227 wrap around the overlapping central portions of the first and second

concentric shafts

210, 220 of the strut 200.

The recessed portion 204 of the second sleeve section 225 is used to receive a grip strip.

Fig. 7B illustrates another cross-sectional view of the external fixation strut of the present disclosure taken from an opposite perspective.

In this fig. 7B, the clamping portion 205 through which the threaded shaft 215 of the clamping bolt passes is clearly visible.

The dynamic mechanism 212 is associated with the female coupling 202. However, alternative reverse embodiments cannot be excluded in which the dynamic mechanism is associated with the male connection 201.

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

More specifically, the male connector 201 is associated with one free end 810 of the second shaft 220 and comprises a pair of

stages

840 and 850 coupled in mechanical order. The first stage 840 is an interconnect stage for the ball joint stage 850 that exits the threaded stem 280 of the male connector 201.

The first stage 840 is connected to the end 810 of the second shaft and includes a support member 845 for a rod 842 whose terminal portion is configured as the ball cage 848 of the ball-and-socket joint for the second stage 850.

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

The rod 842 may be structurally independent of the bracing element 845 or may be integrally formed therewith. In the first case, the rod 842 protrudes from the central hole of the supporting element 845 so as to be substantially coaxial with the second shaft 220.

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

The more protruding portion of the threaded rod 280 represents a male connection for one or the other of the securing rings 510, 520 of the securing system 500. More specifically, threaded rod 280 may be inserted into one of the holes typically provided in the retaining ring and then secured with retaining bolt 530.

A special closing cap 890 is mounted on the screw 280 and closes the socket of the ball-and-socket joint formed by the ball cage 848 and the ball 855.

The special closing cap 890 is formed by two cylindrical portions having different diameters. The first higher or thicker portion 870 is provided with a pair of opposed flat surfaces 860 for allowing insertion of an operating key (not shown).

The first portion 870 has a knurled or milled surface 875 for improving adhesion between the male connector 201 and the

corresponding ring

510 or 520 of the fixation system 500.

The second, smaller portion 880 of the closure cap 890 has a larger diameter and a knurled or milled peripheral surface 885 to enable manual rotation by an operator.

A more detailed description of the internal structure of the male connector 201 is given in the following disclosure of fig. 9, wherein parts and assemblies having the same structure and function as the elements disclosed in fig. 8 are given the same reference numerals.

Fig. 9 is a schematic perspective view of a cross section of the male connector 201 already disclosed with reference to fig. 8.

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

The shaft termination element 940 has a first portion 942 that is interference fit or secured to the end 810 of the second shaft, particularly within the end. The second intermediate portion 944 wraps over the end portion 810 as a peripheral collar, while the third extension portion 946 is provided to interconnect to the support element 845 of the interconnect stage 840.

The second mid portion 944 corresponds to the base portion 830 shown in fig. 8.

In addition, the extension 946 is externally threaded and has a through hole 948 for receiving the stem 842 supporting the ball joint stage 850.

The rod 842 passes through the hole 948 and through another hole of the support element 845.

The support member 845 is threaded onto the externally threaded portion of the extension portion 946, abutting the mid-portion 944, i.e., the base portion 830, at the end of the stroke.

However, when connected to the opposing securing rings 510, 520, the screwing action of the bracing elements 845 may be adjusted to obtain a controlled micrometric axial movement of the entire strut 200.

In other words, by acting on the number of turns of the threaded coupling between the support element 845 and the externally threaded extension 946, the stroke of the entire strut 200 can be controlled very precisely when installed between the two

rings

510, 520.

The ball cage 848 is a protruding portion of the rod 842 and represents the base or socket of the ball joint stage 850.

The ball 855 is of unitary construction with the threaded rod 280, which also has an enlarged diameter 960 closer to the ball 855 and is provided with an externally threaded surface 965.

The particular closure cap 890 is threaded onto the externally threaded surface 965 of the stem portion 280 having the enlarged diameter 960 until such time as the second, smaller portion 880 of the closure cap 890 abuts the ball cage 848.

As can be seen in the cross-section of fig. 9, the interior portion of the closure cap 890 has a hemispherical shape 970 that defines a closure for the ball cage 848 and, together with the ball cage 848, defines a spherical chamber in which the ball 855 of the ball-and-socket joint can move angularly.

Fig. 10 is a perspective view of a female connector 202 associated with one end of a strut 200 according to the present disclosure.

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 coupled in mechanical sequence. The first stage 1040 is a junction stage of the final stage 1050, and the final stage 1050 includes a female element 1060.

The first joint stage 1040 is connected to the end 1010 of the first shaft 210 and comprises a support element 1045 mounted on the end 1010 of the shaft 210 as a closure cap but coupled to the base 1020 of the ball joint 1030.

The support element 1045 has a closed collar 1046 abutting the end 1010 of the shaft 210.

The base portion 1020 has an externally threaded portion 1025 and is connected to a support element 1045 by a threaded adjustment ring 1035. The ring 1035 is part of the adjustment mechanism 212, which will be described in detail with reference to fig. 11 below, and has a knurled or milled peripheral surface for manual rotation by an operator.

Advantageously, the adjusting ring is made of a reinforced plastic material transparent to X-ray radiation.

The ball-and-socket joint 1030 protruding from the base 1020 has a plurality of regularly spaced holes 1037, for example four holes. One of the holes 1033 is larger than the other holes 1037.

The final stage 1050 of the female connector 202 has a more distal portion 1055 coupled to the ball joint 1030 and a final cylindrical portion 1090 including a proximal end of a female element 1060 with internal threads for receiving an interconnecting bolt (not shown) to connect one end of the strut 200 to the ring of the fixation system 500.

The proximal final cylindrical portion 1090 is provided with an opposite flat surface 1070 for insertion of the operating key, while the distal portion 1055 has an enlarged annular collar 1080 with a knurled or milled peripheral surface for manual rotation by the operator.

Fig. 11A shows a cross-sectional perspective view of the same female connector 202 of fig. 10, but showing in more detail the already mentioned adjustment mechanism 212, which enables an independent quick and gradual fine adjustment of the length of the entire prop 200.

Generally, the components and assemblies having the same structure and function as disclosed are denoted by the same reference numerals.

As can be appreciated from this cross-sectional view, ball joint 1030 protrudes from base 1020 which has external threads.

This particular structure, comprising a ball joint 1030 and its base 1020, is mounted on a support element 1045 fixed at the end 1010 of the shaft 210 and has a through hole 1110 housing a pin 1120 having a T-shaped inner shaft 1125 sliding in the hole 1135 of the support element 1045 and an enlarged portion 1140 sliding along the through hole 1110.

A first transverse pin 1148 is fixed by means of a support element 1045 and passes through the stem of the inner shaft 1125 at its distal end portion.

The support element 1045 is realized by a synthetic plastic material transparent to X-ray radiation and can be considered as a plastic sleeve closing the end 1010 of the shaft 210, while providing a base for a dynamic mechanism to be disclosed below.

More specifically, support element 1045 is configured as a double sleeve, with a portion inserted into shaft end 1010, collar 1046 bearing against shaft end 1010, and a nose 1047 slidably supporting the interior of base 1020 of first stage 1040.

The T-shaped inner shaft 1120 is advantageously implemented by a radiolucent metal component, such as aluminum, or alternatively a reinforced plastic material.

The elastic element 1150 is disposed inside the support element 1045. More specifically, the spring 1150 is wound around the rod 1125 of the inner shaft 1120 inside the support element 1045 to produce a resilient action in cooperation with the screwing action of the threaded adjustment ring 1035 of the externally threaded portion 1025 of the base 1020.

A second transverse pin 1142 is secured with the base 1020 and passes through the enlarged portion 1140 of the T-shaped inner shaft 1120. The second transverse pin 1142 is slidable within the elongated slot 1122, similar to a grommet formed in the center of the T-shaped inner shaft 1120, and is aligned along 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 elongate slot 1122.

The following components: a support element or plastic sleeve 1045, a base 1020; the threaded portion 1025, the threaded adjustment ring 1035, the inner T-shaped shaft 1120, and the spring 1150 together comprise the dynamic adjustment mechanism 212.

The dynamizing mechanism 212 of the present embodiment includes a T-shaped inner shaft 1120 made of a plastic material assembled to a plastic support element 1045 along with a first transverse pin 1148 for assembling the two plastic parts. The second transverse pin 1142 acts as a mechanical stop for the compression spring 1150 and avoids any accidental disassembly of the strut.

Acting manually on the threaded adjustment ring 1035, the offset of the base 1020 relative to the end 1010 of the shaft 210 can be adjusted using the ball joint 1030 and against the resilient force of the spring 1150. In this manner, a smooth, independent, quick and gradual fine adjustment of the length of the entire stanchion 200 is possible via the adjustment mechanism 212.

In a preferred embodiment, this length adjustment is at least 3 millimeters.

The structure of the female coupling 202 is completed by a spring-loaded mechanism 1100 disposed in the final stage 1050 around the female element 1060.

More specifically, the female element 1060 of the female connector 202 is realized at the end of the stem 1160, slidable in a tubular hole 1180 formed by a first and a second coaxial

tubular cavities

1180, 1190 having different diameters, and realized inside the final proximal cylindrical portion 1090.

The stem 1160 has a distal portion 1195 which is threaded to screw into a corresponding seat provided in the ball joint 1030.

The spring-loaded mechanism 1100 includes a spring 1111 housed inside the first tubular cavity 1180 and wound around a more proximal portion of the rod 1160 forming the female element 1060.

The post 1160 extends through the aperture 1133 of ball joint 1030 and this aperture 1133 communicates with the larger aperture 1033 of ball joint 1030 such that the final stage 1050, which includes the proximal cylindrical portion 1090 of female element 1060, rotates at least 90 ° about ball joint 1030.

The penetration of the threaded distal portion 1195 of the stem 1160 in the corresponding seat of the ball joint can be adjusted by manually acting on the enlarged annular collar 1080 of the distal portion 1055, thereby adjusting the relative distance between the final stage 1050 and the first stage 1040. This also achieves a 90 "collapsible" configuration of connector 202 that is different from the working configuration in which the angular motion between first stage 1040 and final stage 1050 is in the range of 0 to 45.

Fig. 11B shows a cross-sectional perspective view, taken from a vertical perspective, of the same female connector 202 of fig. 11A.

The components shown in this figure are identical and are given the same reference numerals as in figure 11A.

In this figure, it is particularly evident that the inner T-shaped shaft 1120 is made of plastic material and is assembled in a plastic support element 1045 together with a first transverse pin 1148 for connecting the two plastic parts. The second transverse pin 1142 is also distinct and acts as a mechanical stop for the compression spring 1150 and avoids any accidental disassembly of the strut.

Threaded adjustment ring 1035 is shown in a position closer to base 1020 and where a gap is provided with respect to end 1010 of shaft 210 and spring 1150 is released.

A comparison of the larger bore 1033 of ball joint 1030 with the opposite smaller bore 1037 is also shown.

Fig. 12A is another perspective view of the female coupling of fig. 10 taken from a different perspective.

Fig. 12B is a perspective view of the female coupling of fig. 10, where it can be seen that the internal spring-loaded mechanism 1100 includes a spring 1111 wrapped around a rod 1160.

Rotation of the annular collar 1080 of the distal portion 1055 may adjust the compression of the spring 1111.

Fig. 12C is a slightly enlarged cross-sectional view of the female coupling of fig. 12B, and more particularly of the final stage 1050 thereof, wherein it can be clearly seen that the distal threaded portion 1195 of the stem 1160 is threaded into a seat provided in the ball joint 1030.

Rotation of the annular collar 1080 adjusts the coupling between the final stage 1050 and the first stage 1040, including ball joint 1030, and causes the final stage 1050 to rotate toward a greater angular motion to achieve a 90 "collapsible" configuration.

Fig. 13A shows a cross-sectional view of the first stage 1040 of the female coupling 202 and the adjustment mechanism 212, enabling independent rapid and gradual fine adjustment of the length of the strut 200.

It will be appreciated that when the adjustment ring 1035 abuts the closed collar 1046 of the support element 1045, the screwing action of the adjustment ring may be exerted on the externally threaded portion 1025 of the base portion 1020, thereby forcing the base portion 1020 toward the support element 1045.

The maximum extension of the screwing action can be adjusted as desired. Without limiting applicant's rights, in the preferred embodiment disclosed herein, this maximum extension has been selected to be 3mm, as shown in fig. 13B.

In the maximum extended configuration of fig. 13A and 13B, the second lateral pin 1122 is at one end of the elongated slot 1042 and the spring 1150 is at its maximum relaxed extension.

Fig. 13C shows another cross-sectional view of the first stage 1040, where the adjustment ring 1035 is threaded over the largest portion of the external threaded portion 1025 of the base 1020, while the enlarged portion 1140 of the T-shaped inner shaft 1120 protrudes deeper towards the ball joint 1030, thereby reducing the overall extension of the strut 200.

In this fig. 13C, it can be appreciated that the second transverse pin 1122 abuts the opposite end of the elongated slot 1046 in the final retracted configuration if compared to the other fig. 13A and 13B.

Referring now more particularly to fig. 14A-14C, an alternative embodiment of the female connector 202 of the present disclosure is disclosed.

More specifically, an alternative embodiment relates to a dynamic adjustment mechanism 1412 associated with the female coupling 202.

Fig. 14A is a cross-sectional view of an alternative embodiment of the dynamic mechanism 1412 associated with the first stage 1440 of the female coupling 202, where components and assemblies having the same structure and function as the elements disclosed in the previous fig. 10, 11, 12, and 13 are given the same reference numerals.

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

A bushing 1420 is disposed about the inner shaft 1410 at the bottom of the base housing the resilient member 1150. The bushing allows for easy movement between the two

portions

1045 and 1410. In addition, a first distal transverse pin 1149 is fixed with the inner shaft 1410 and slides with the shaft within a slot 1414 provided in the sleeve support element 1045. This transverse pin 1149 serves to avoid any accidental disassembly of the stanchion.

The terminal portion 1430 of the inner shaft 1410 is coupled in shape with the interior of the base 1020 and presents an enlarged portion that is traversed by a proximal second pin 1441 that secures the shaft to the base 1020. Thus, the dynamic mechanism 1412 associated with the first stage 1440 of this female connector embodiment provides a length fine adjustment of at least 3mm as compared to the compression of the spring 1150 and the distal transverse pin 1149 sliding within the slot 1414.

Even in this embodiment, when the adjustment ring 1035 is abutted against the closed collar 1046 of the support element 1045, the screwing action of the adjustment ring 1035 may be exerted on the externally threaded portion 1025 of the base portion 1020, thereby forcing the base portion 1020 toward the support element 1045.

The maximum extension of the screwing action can be adjusted as desired. Without limiting applicant's rights, in the preferred embodiment disclosed herein, this maximum extension has been selected to be 3mm, as shown in fig. 14B.

FIG. 14C shows another cross-sectional view of the first stage 1440 with the adjustment ring 1035 threaded onto the largest portion of the externally threaded portion 1025 of the base 1020, while the first distal transverse pin 1149 has reached one end of the slot 1414, compressing the base 1020 and the support element 1045, thereby reducing the overall extension of the strut 200.

Referring now more particularly to fig. 15A-15C, an alternative embodiment of the female connector 202 of the present disclosure is disclosed. More particularly, an alternative embodiment involves a dynamic adjustment mechanism 1512 associated with the female coupling 202.

Fig. 15A is a cross-sectional view of an alternative embodiment of the dynamizing mechanism 1512 associated with the first stage 1540 of the female link 202, wherein components and assemblies having the same structure and function as the elements disclosed in the previous fig. 10, 11, 12, and 13 are given the same reference numerals.

As in the previous embodiment, radiolucent shaft end 1010 is closed by a support member 1545 formed as a double sleeve, with the main portion inserted into shaft end 1010, with collar 1546 abutting against the shaft end, and with nose portion 1547 slidably supporting the interior of base portion 1520 of first stage 1540.

The alternative dynamic mechanism 1512 is provided with an inner shaft 1510 that is made of a radiolucent alloy, such as aluminum.

The inner shaft 1510 has an end 1530 provided with a threaded portion that is secured to the base 1020 of the first stage 1540.

On the opposite distal end 1570 of the inner shaft 1510 is a groove 1542 that is axially aligned along the longitudinal extent of the shaft 1510.

The main portion of the support member 1545 has a transverse pin 1548 that passes through a slot 1542 in the inner shaft disposed near its distal end. During the dynamic adjustment, the transverse pin 1548 is guided along the groove 1542.

A collar 1560 is formed at a predetermined distance from the inner shaft end 1570 to support a resilient member, i.e., a spring 1550, which is captured between such collar 1560 and the transverse pin 1548.

As can be appreciated from the example of fig. 15C, when the base 1520 of the first stage 1540 is fully retracted against the collar 1546 of the support member 1545, the pin 1548 is at one end of the slot 1542 and the spring 1550 is compressed.

The dynamic mechanism of fig. 15A, 15B and 15C is provided with an inner shaft made of aluminum that is secured to the final female stage of the strut by a first stage 1560. The resilient element is accommodated in the distal main part of the plastic support sleeve 1545, thus enabling a stronger plastic sleeve due to the increased material in the critical areas. This configuration and construction helps to keep the components on axis, avoiding any accidental bending that may occur.

Furthermore, the transverse pin 1548 acts as a mechanical stop for the compression spring 1550 to avoid any accidental disassembly of the strut.

The embodiments previously disclosed in their various configurations have the common great advantage of providing a post that is easy for the surgeon to use and is very practical to transport in sterile packaging.

The use of reinforced plastic materials for the connectors and

telescoping shafts

210 and 220 results in a reduction in overall strut weight and, if compared to other similar devices of the prior art, a lighter construction.

It should be understood that the particular embodiments described herein are illustrative and not restrictive of the present disclosure. The principal features of the disclosure can be employed 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 procedures described herein. Such equivalents are considered to be within the scope of this disclosure and are covered by the claims.

The use of the word "a" or "an" when used in conjunction with the word "comprising" in the claims and/or the specification may mean "one," but it is also consistent with the meaning of "one or more," at least one, "and" one or more. The word "or" as used in the claims is intended to mean "and/or" unless explicitly indicated to refer only to alternatives or alternatives are mutually exclusive, although the present disclosure supports the definition of alternatives and "and/or". Throughout this application, the word "about" is used to indicate that a value includes the inherent variation of error of the apparatus, method, or subject that is used to determine the value.

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

Claims

1. An improved external fixation brace (200), comprising:

-an elongated body comprising a first hollow tubular shaft (210) and a second hollow tubular shaft (220);

-opposite connectors (201, 202) coupled respectively to an end of the first shaft (210) or to an end of the second shaft (220) and each comprising a ball joint;

-one shaft (220) having an inner diameter slightly larger than the outer diameter of the other shaft (210) so as to house said other shaft (210) inside in a slidable telescopic manner;

-the first and second shafts (210, 220) of the strut (200) are realized in a synthetic radiolucent plastic material;

-a clamping element, provided near the overlapping ends of the first and second shafts (210, 220), for providing a quick clamping action, preventing telescopic sliding of one shaft (210) within the other shaft (220);

-a manually operated fixing element acting on the gripping element for applying the quick gripping action;

-a sleeve (230) arranged around a central portion of the strut (200) where the first and second shafts (210, 220) overlap;

-a clamping band (204) surrounding the sleeve and comprising opposite and facing clamping portions (205, 206), the clamping portions (205.

2. The improved external fixation strut (200) of claim 1, wherein said threaded connection is a clamping bolt (260), said clamping bolt (260) passing through a through hole (211) of said clamping portion (205, 206) and being received within a nut (207).

3. The improved external fixation strut (200) of claim 2, wherein said clamping bolt (260) has a head (261) coupled to a removable manual butterfly wrench (250).

4. The improved external fixation strut (200) of claim 2, wherein said sleeve (230) is configured with a first sleeve portion (225) having an inner diameter substantially corresponding to the outer diameter of the first shaft (210) and a second sleeve portion (235) having an inner diameter substantially corresponding to the outer diameter of the second shaft (220); the grip strap (204) surrounds the second sleeve portion (235).

5. An improved external fixation brace (200), comprising:

-wherein each ball and socket joint is configured such that the corresponding connection (201.

6. An improved external fixation brace (200), comprising:

-one shaft (220) having an inner diameter slightly larger than the outer diameter of the other shaft (210) so as to house the other shaft (210) inside in a slidable telescopic manner;

-wherein a dynamic mechanism (212) is associated with one of said opposite connectors (212) and comprises a first stage (1040); a ball joint (1030) associated with one end (1010) of the shaft (210) and comprising a ball-and-socket joint supported by a base (1020), a screw mechanism adjusting the protrusion of said base (1020) with respect to the internal elastic element and a final stage (1050) comprising a female connector.

7. The improved external fixation strut (200) of claim 6, wherein said protruding base (1020) is axially slidably coupled to a support element (1045, 1545) fixed to a shaft end (1010) and has an external threaded portion engaged by an adjustment ring (1035) against said support element (1045, 1545) to resist the elastic force of said internal elastic element.

8. The improved external fixation strut (200) of claim 7, comprising an inner shaft (1120.

9. The improved external fixation strut (200) of claim 6, wherein said dynamizing mechanism comprises a radiolucent component.

10. The improved external fixation strut (200) according to claim 6, wherein said final stage (1050) is mechanically coupled to a ball joint (1030) of said first stage (1040) by means of a rod, one end of which is screwed into said ball joint (1030) and the other end is provided with a female element of said female connection.

11. The improved external fixation strut (200) of claim 10, wherein said rod is slidable within said final stage (1050) to resist the spring force of a spring-loaded mechanism (1100) incorporated in said final stage (1050) around said rod.

12. The improved external fixation strut (200) according to claim 6, wherein said dynamizing mechanism is for independent rapid and progressive fine dynamizing adjustment of the length of said strut, is associated with said female connector, and comprises a radiolucent assembly.

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

14. The securing system (500) of claim 13, wherein each strut (200) includes opposing male (201) and female (202) connectors, each including a ball-and-socket joint, such that the corresponding strut makes angular movement at a spherical angle of at least 90 ° to fold the securing system (500) for packaging and shipping purposes.

15. A fixation system according to claim 13, wherein a dynamic mechanism comprising a radiolucent assembly is associated with one of the opposite connections (201, 202) and comprises a first stage associated with one end of the shaft and comprising a ball joint supported by a base, a threaded mechanism adjusting the protrusion of the base with respect to the inner elastic element and a final stage comprising a female connection.