Adjustable strut assemblies for external fixation systems

Abstract

To provide length-adjustable strut assemblies and corresponding external fixation systems.SOLUTION: A strut assembly 10 includes elongate first and second end members, an elongate intermediate member, and first and second adjustment mechanisms. The intermediate member comprises a threaded rod fixedly coupled within an axial cavity of the member, and is rotatably fixed and axially translatable within an axial cavity of the first end member 12. An end portion of the second end member 14 is received within the axial cavity of the intermediate member 16, and the second end member comprises an axial cavity threadably coupled with the threaded rod. The first adjustment mechanism is configured to selectively axially fix the intermediate member relative to the first end member. The second adjustment mechanism is configured to selectively rotate the second end member with respect to the threaded rod to axially translate the second end member relative to the intermediate member.SELECTED DRAWING: Figure 1

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application completes and claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 724,462, entitled "Struts and Strut Assemblies for External Bone Fixation Systems," filed August 29, 2018, the contents of which are expressly incorporated herein by reference in their entirety. [Technical Field]

[0002] The present disclosure relates generally to struts for external fixation systems and related methods, and more particularly to adjustable strut assemblies for external fixation systems and related methods that provide relatively rapid length adjustment over a relatively wide length adjustment range. [Background technology]

[0003] External fixation devices have been used to treat bone and tissue conditions by positioning and orienting bone or tissue fragments in desired relative positions and orientations and adjusting their relative positions and orientations based on specific clinical needs. One form of external fixation device is a hexapod-type fixation device. A hexapod-type device, or more formally known as a Stewart platform, includes a six-degree-of-freedom (6DOF) parallel manipulator or column. Generally, these devices have the ability to manipulate an object relative to a base point in translation on all three orthogonal axes (X, Y, Z position) and rotation about all three orthogonal axes (roll, pitch, yaw attitude). Other types of external fixation devices utilize fewer or more than six columns.

[0004] External fixation systems also typically include a pair of bases or "rings" that serve as the foundation for bone fixation. The bases are typically connected to six struts that extend between them. The struts and bases are usually connected via spherical or cardan joints that allow three degrees of rotation around three orthogonal axes. Some of these struts allow for length adjustment, but the minimum and / or maximum length may not meet the needs of a particular clinical situation. For example, minimizing the distance between the bases to a distance shorter than that achieved by a particular strut requires the use of shorter struts, which naturally limits the adjustment range (i.e., maximum length) of the struts.

[0005] As a result, current hexapod bone fixation systems utilize a set of struts of varying lengths (i.e., a range of lengths) that provide "short" struts for use when the bases need to be closer together and "long" struts for use when the bases need to be further apart. In many instances, these struts must be replaced with struts of the next length to gradually lengthen or shorten them during the bone or tissue correction process, which can be time-consuming and, if the replaced struts cannot be reused, expensive. Further complicating such systems is the fact that different situations require struts of different lengths. For example, when there is excessive initial flexion or rotation, different lengths of struts are usually required. Selecting the correct combination of strut lengths for such situations is a time-consuming process that is typically performed by trial and error in the operating room. Such systems and situations also result in excessive inventory, which is costly and often confusing to use properly.

[0006] Aside from being cumbersome, physically altering the struts also limits the available range of motion of the system when attempting to correct the deformity in an emergency manner. In this situation, struts are typically not added until such an emergency correction is performed and maintenance of the reduction is left to the operating room staff, while another member of the operating room staff selects which struts fit between the bases in the prescribed positions. This process takes a lot of time and requires a large amount of inventory.

[0007] Current hexapod fixation systems also typically utilize connections between the base and the struts that require the use of one or more fasteners that must be tightened during application. Connecting the ends of the six struts to the base (i.e., 12 connections) can be a difficult and time-consuming task, sometimes involving trial and error. Compounding the problem is the fact that many current hexapod fixation systems utilize separate fasteners that must be applied with tools. These fasteners and tools further increase the collection of parts and materials that must be kept track of in the operating room environment while the fixation system is in use, e.g., while attempting to maintain reduction.

[0008] Therefore, a strut assembly, an external fixation system including such a strut assembly, and related methods that provide a wide range of length adjustment and that can be adjusted relatively quickly and easily, especially while connected to the base / user, are desirable. Summary of the Invention

[0009] In one aspect, the present disclosure provides a strut assembly for an external fixation system for bone and / or tissue, the strut assembly comprising: an elongate tubular first end member; an elongate tubular intermediate member rotationally fixed and axially translatable within an axial cavity of the first end member and extending therefrom out a first end portion of the first end member; and an elongate tubular second end member received within the axial cavity of the intermediate member and extending therefrom out a second end portion of the intermediate member. An intermediate strut body is rotationally fixed and axially translatably coupled within the first end member and extends axially from the first end member out the first end portion of the first end member. The strut assembly further comprises a first adjustment mechanism provided at a first free end portion of the first end member configured to selectively allow the intermediate member to translate freely axially within the first end member and to selectively axially secure the first end member and the intermediate member. The strut assembly further comprises a threaded rod secured within an axial interior cavity of the intermediate member. The axial cavity of the second member is threadably engaged with the threaded rod within the cavity of the intermediate member and extends axially from the cavity out the second end portion of the intermediate member. The strut assembly further comprises a second adjustment mechanism provided at a second free end portion of the intermediate member configured to selectively rotate the second end member relative to the intermediate member and the threaded rod to axially translate the second end member relative to the intermediate member.

[0010] In another aspect, the present disclosure provides a strut assembly for an external fixation system, comprising an elongated first end member, an elongated intermediate member, an elongated second end member, a first adjustment mechanism, and a second adjustment mechanism. The first end member comprises a first end portion, a second end portion, and a first axial cavity extending from the second end portion. The intermediate member comprises a third end portion, a fourth end portion, a second axial cavity extending from the third end portion, and a threaded rod fixedly connected within the second axial cavity. The intermediate member is pivotally fixed within the first axial cavity of the first end member and axially translatable, extending from the first axial cavity through the second end portion. The second end member comprises a fifth end portion, a sixth end portion, and a third axial cavity extending from the fifth end portion. At least a fifth end portion of the second end member is received within the second axial cavity of the intermediate member, and the third axial cavity is threadedly engaged with the threaded rod of the intermediate member. The second end member extends from the second axial cavity through the fourth end portion. A first adjustment mechanism is disposed at the second end portion of the first end member and configured to selectively allow the intermediate member to translate freely axially within the first axial cavity and selectively axially fix the intermediate member relative to the first end member. A second adjustment mechanism is disposed at the fourth free end portion of the intermediate member and configured to selectively rotate the second end member relative to the intermediate member and the threaded rod to translate the second end member axially relative to the intermediate member.

[0011] In some embodiments, the first end portion of the first end member comprises a first joint configured to couple to a first external fixation base, and in some embodiments, the sixth end portion of the second end member comprises a second joint configured to couple to a second external fixation base.

[0012] In some embodiments, the body portion of the first end member includes an axially extending slot, and the intermediate member is pivotally fixed and axially translatable within the axial cavity of the first end member by a radially extending first pin coupled to the intermediate member and received in the slot of the first end member. In some such embodiments, the first pin is coupled to a third end portion of the intermediate member. In some such embodiments, the first pin is further coupled to the threaded rod to pivotally and axially fixedly couple the threaded rod and the intermediate member. In some such embodiments, the first pin is coupled to a distal end portion of the threaded rod.

[0013] In some embodiments, at least a fifth end portion of the second end member received within the second axial cavity of the intermediate member is radially disposed between the threaded rod and the body portion of the intermediate member, hi some embodiments, the third axial cavity of the intermediate member includes internal threads, and the threaded rod includes external threads that threadably mate with the internal threads of the third axial cavity.

[0014] In some such embodiments, the second end portion of the first end member includes external threads, and the first adjustment mechanism includes a first collar member having internal threads that mesh with the external threads of the second end portion, and rotation of the first collar member about the second end portion causes the first collar to translate axially along the second end portion. In some such embodiments, the fastening portion of the first collar member is disposed axially past the second end portion of the first end member and includes a tapered bearing surface, and the first adjustment mechanism further includes a friction member disposed radially between the outer surface of the body portion of the intermediate member and the bearing surface. In some such embodiments, axial translation of the first collar along the second end portion toward the first end portion causes the bearing surface to press the friction member radially against the outer surface of the body portion of the intermediate member, thereby selectively axially securing the intermediate member relative to the first end member. In some embodiments, the bearing surface comprises a surface that slopes toward the outer surface of the body portion of the intermediate member as it extends axially away from the second end portion. In some embodiments, the friction member comprises a deformable ring member. In some such embodiments, the deformable ring member comprises a segmented ring or a split ring. In some such embodiments, the outer surface of the body portion of the intermediate member comprises a surface texture that increases friction.

[0015] In some such embodiments, the second adjustment mechanism includes a second collar member axially fixed and pivotally coupled to the fourth end portion of the intermediate member, hi some such embodiments, the body portion of the second end member includes an axially extending slot, and the second collar member is pivotally fixed to the second end member by a second radially extending pin coupled to the second collar member and received in the slot of the second end member such that rotation of the second collar member about the fourth end portion causes axial translation of the second end member relative to the intermediate member.

[0016] In another aspect, the present disclosure provides an external fixation system for bone and / or tissue comprising a first base, a second base, and a plurality of posts extending between the first base and the second base, at least one of the plurality of posts comprising a post assembly disclosed herein.

[0017] In some embodiments, more than one of the plurality of struts comprises a strut assembly disclosed herein. In some embodiments, each of the plurality of struts comprises a strut assembly disclosed herein. In some embodiments, the plurality of struts comprises six struts. In some embodiments, the first base is configured to couple with a first bone and / or tissue of the patient, and the second base is configured to couple with a second bone and / or tissue.

[0018] In some embodiments, the first end portion of the first end member includes a first joint configured to couple to a first external mounting. In some embodiments, the sixth end portion of the second end member includes a second joint configured to couple to a second external mounting. In some embodiments, the body portion of the first end member includes an axially extending slot, and the intermediate member is pivotally fixed and axially translatable within the first axial cavity of the first end member by a radially extending first pin coupled to the intermediate member and received in the slot of the first end member. In some such embodiments, the first pin is coupled to a third end portion of the intermediate member. In other such embodiments, the first pin is further coupled to the threaded rod, pivotally and axially fixedly coupling the threaded rod and the intermediate member. In some embodiments, the first pin is coupled to a distal end portion of the threaded rod.

[0019] In some embodiments, at least a fifth end portion of the second end member received within the second axial cavity of the intermediate member is radially disposed between the threaded rod and the body portion of the intermediate member, hi some such embodiments, the third axial cavity of the intermediate member includes internal threads, and the threaded rod includes external threads that threadably mate with the internal threads of the third axial cavity.

[0020] In some such embodiments, the second end portion of the first end member includes external threads, and the first adjustment mechanism includes a first collar member having internal threads that mesh with the external threads of the second end portion, and rotation of the first collar member about the second end portion causes the first collar to translate axially along the second end portion. In some such embodiments, the fastening portion of the first collar member is disposed axially past the second end portion of the first end member and includes a tapered bearing surface, and the first adjustment mechanism further includes a friction member disposed radially between the outer surface of the body portion of the intermediate member and the bearing surface. In some such embodiments, axial translation of the first collar along the second end portion toward the first end portion causes the bearing surface to press the friction member radially against the outer surface of the body portion of the intermediate member, thereby selectively axially securing the intermediate member relative to the first end member. In some such embodiments, the bearing surface comprises a surface that slopes toward the outer surface of the body portion of the intermediate member as it extends axially away from the second end portion. In some such embodiments, the friction member comprises a deformable ring member. In some such embodiments, the deformable ring member comprises a segmented ring or a split ring. In some embodiments, the outer surface of the body portion of the intermediate member comprises a surface texture that increases friction.

[0021] In some embodiments, the second adjustment mechanism includes a second collar member axially fixed and pivotally coupled to the fourth end portion of the intermediate member. In some such embodiments, the body portion of the second end member includes an axially extending slot, and the second collar member is pivotally fixed to the second end member by a second radially extending pin coupled to the second collar member and received in the slot of the second end member, such that rotation of the second collar member about the fourth end portion causes axial translation of the second end member relative to the intermediate member. These and other objects, features, and advantages of the present disclosure will become apparent from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings.

[0022] For purposes of illustrating the external bone fixation systems and related methods described herein, example embodiments are shown, which are in no way limiting as to the exact configuration and operation of the disclosed external fixation systems, and other similar embodiments are contemplated. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a front perspective view of an exemplary adjustable strut assembly according to the present disclosure. [Figure 2] FIG. 2 is a rear perspective view of the example adjustable strut assembly of FIG. 1 in accordance with the present disclosure. [Figure 3] FIG. 2 is a rear view of the example adjustable strut assembly of FIG. 1 in accordance with the present disclosure. [Figure 4] FIG. 2 is a side view of the example adjustable strut assembly of FIG. 1 in accordance with the present disclosure. [Figure 5] FIG. 2 is a front view of the example adjustable column assembly of FIG. 1 according to the present disclosure. [Figure 6] 6 illustrates a vertical cross section as shown in FIG. 5 of the exemplary adjustable column assembly of FIG. 1 in accordance with the present disclosure. [Figure 7] 7 is a partial enlarged view of the cross-sectional view of FIG. 6 illustrating the example adjustable strut assembly of FIG. 1 according to the present disclosure. [Figure 8] 8 is a partial enlarged view of the cross-sectional view of FIG. 7 showing the example adjustable strut assembly of FIG. 1 according to the present disclosure. [Figure 9] 8 is another enlarged partial view of the cross-sectional view of FIG. 7 illustrating the example adjustable strut assembly of FIG. 1 according to the present disclosure. [Figure 10] 2 illustrates a top end of the example adjustable column assembly of FIG. 1 in accordance with the present disclosure. [Figure 11] 2 illustrates a rear end of the example adjustable strut assembly of FIG. 1 in accordance with the present disclosure. [Figure 12] FIG. 10 is a top perspective view of an exemplary external fixation system utilizing the exemplary strut assembly of FIGS. 1-9 in a first, relatively reduced configuration according to the present disclosure. [Figure 13] FIG. 13 is a front view of the exemplary external fixation system of FIG. 12 in accordance with the present disclosure. [Figure 14] FIG. 13 is a side view of the exemplary external fixation system of FIG. 12 in accordance with the present disclosure. [Figure 15] FIG. 13 is a top view of the exemplary external fixation system of FIG. 12 in accordance with the present disclosure. [Figure 16] FIG. 16 is a top perspective view showing the exemplary external fixation system of FIGS. 12-15 in a second, relatively expanded configuration in accordance with the present disclosure. [Figure 17] FIG. 17 is a front view of the exemplary external fixation system of FIG. 16 in accordance with the present disclosure. [Figure 18] FIG. 17 is a side view of the exemplary external fixation system of FIG. 16 in accordance with the present disclosure. [Figure 19] FIG. 17 is a top view of the exemplary external fixation system of FIG. 16 in accordance with the present disclosure. Detailed Description

[0024] When describing elements of various embodiments of the present invention, the articles "a," "one," "one "An," "the," and "said" refer to one or more components. The terms "comprising," "including," and "having" are intended to mean "comprising," "including," and "having" are intended to be non-exclusive and mean that there may be additional elements other than the listed elements. Example parameters do not exclude other parameters of the disclosed embodiments. Components, aspects, features, configurations, arrangements, methods of use, etc. described, exemplified, or otherwise disclosed herein with respect to any particular embodiment are equally applicable to any other embodiment disclosed herein.

[0025] The present disclosure provides a length-adjustable strut assembly 10 for an external fixation system, as shown in FIGS. 1-11 , that has a wide adjustment range and can be quickly and easily manually adjusted while still coupled to a foundation / base plate (and therefore to a user). The present disclosure also provides an external fixation / parallel manipulator system 100 (e.g., a six-degree-of-freedom (6DOF) fixation system) incorporating one or more strut assemblies 10, as well as related fixation methods, as shown in FIGS. 12-19 . For example, in some embodiments, the external fixation system 100 can include at least one strut assembly 10. In other embodiments, the external fixation system 100 can include multiple strut assemblies 10. In some embodiments, each strut of the external fixation system 100 can be comprised of a strut assembly 10. In some embodiments, the external fixation system 100 is a bone and / or tissue fixation system.

[0026] The strut assembly 10 enables the external fixation system 100 to have the desirable stability and mobility characteristics of conventional parallel manipulator systems, but without the time-consuming strut length selection, strut length constraints, and difficult strut assembly and disassembly. The strut assembly 10, and therefore a fixation system 100 including one or more strut assemblies 10, provides a relatively wide range of motion / adjustment (including coarse and fine adjustment ranges), eliminating (or at least reducing) the need for replacement of one or more strut assemblies 10 during reduction / distraction procedures. In some embodiments, the strut assembly 10, and therefore a fixation system 100 including one or more strut assemblies 10, is particularly advantageous for repairing fractures or deformities, such as fractures or deformities of relatively long bones.

[0027] 1-11, each strut assembly 10 is formed from an assembly of an axially elongated tubular first end member or strut body 12, a second axially elongated tubular first end member or strut body 14, and an axially elongated tubular intermediate member strut body 16 connecting and extending between the first end member 12 and the second end member 14. As described further below, the strut assembly 10 further comprises a threaded rod 18 fixed within the intermediate member 16 and threadedly engaged within the axially extending cavity of the second end member 14. The intermediate member 16 is further coupled for axial translation within the axially extending cavity of the first end strut body 12. The strut assembly 10 may have or define a longitudinal axis X-X, as shown in Figures 1, 4, and 5, and the overall length of the assembly along the axis X-X may be adjustable (either coarsely or finely). The axial ends of the strut assembly formed by the first and second end members 12, 14 may include first and second joints or connection mechanisms 22, 24, respectively, as shown in Figures 1-6, 10, and 11. The first and second joints 22, 24 are configured to couple to / with one of the first and second foundations or base plates 120, 130 of the external fixation system 100, as shown in Figures 12-19.

[0028] 12-19, the first coupling 22 can be coupled to the first base 120, and the second coupling 24 can be coupled to the second base 130. In this manner, the relative axial positioning of the intermediate member 16 within / along the first end member 12 and / or the relative axial positioning of the second end member 14 within / along the intermediate member 16 can be adjusted along the axis X-X of the strut assembly 10 to provide a relatively wide range of length adjustment of the strut assembly 10, and consequently the distance and / or orientation between the first and second bases 120, 130, as shown, for example, in FIGS. 10-13 compared to FIGS. 14-17.

[0029] The first and second bases 120, 130 may be annelid or partially annelid, extending at least partially around the opening and / or axis (and potentially at least partially around bone and / or tissue when worn on the body). Multiple strut assemblies 10 may be coupled to the first and second bases 120, 130 around their axes and / or openings. For example, as shown in FIGS. 12-19 , multiple strut assemblies 10 may be circumferentially arranged and coupled to the first and second bases 120, 130, and each strut assembly 110 may be attached to the first and second bases 120, 130 via first and second joints 22, 24, respectively, at various positions around the base axes and / or openings. As such, the strut assemblies 10 may be angled relative to the axes of the first and second bases 120, 130.

[0030] As shown in Figures 12-19, the strut assemblies 10 can be arranged and coupled in pairs to the first and second bases 120, 130 via coupling members 132, and such pairs of strut assemblies 10 (and coupling members 132) can be circumferentially arranged / spaced apart on the first and second bases 120, 130. Each pair of strut assemblies 10 can be coupled to the first and second bases 120, 130 in alternating orientations, as shown in Figures 12-19. Each pair of strut assemblies 10 coupled to the first and second bases 120, 130 can extend in opposite axial and / or angular directions to the other base 120, 130. For example, as shown in Figures 12-19, one support column assembly 10 of a pair may extend and connect from a first base 120 to a second base 130 via a first joint 22 at a clockwise angle (and arrangement), and the other support column assembly 10 of the pair may extend and connect from the first base 120 to the second base 130 via a second joint 24 at a counterclockwise angle (and arrangement).

[0031] The intermediate member 16 can be selectively slidably axially adjusted within the cavity of the first end member 12 to provide coarse adjustment of the axial length of the strut assembly 10. The second end member 14 can be selectively threadably axially adjusted within the cavity of the first end member 12 and about / along a threaded rod 18 fixed within the cavity of the intermediate member 16 to provide relatively fine adjustment of the axial length of the strut assembly 10. In this manner, the strut assembly 10 can have a relatively wide range of adjustment to reduce or increase the axial distance between the portions of the first and second bases 120, 130 (and between bone or tissue fragments coupled to the bases), as shown in Figures 12-19. This relatively wide range of axial adjustment of the strut assembly 10 is provided without the need to replace or add strut assemblies 10, which advantageously frees the surgeon to focus on the orthopedic condition and the reduction of the fracture or deformity, and also reduces inventory requirements.

[0032] As shown in Figures 1-7 and described above, each strut 10 includes a first end member 12, a second end member 14, and an intermediate member 16 connecting and extending between the first end member 12 and the second end member 14. The strut 10 includes a threaded rod 18 fixed within a cavity of the intermediate member 16 and threadedly engaged within a cavity of the second end member 14. The intermediate member 16 is selectively axially translatably coupled to the interior of the cavity of the first end member 12 via a first adjustment mechanism provided at a distal portion of the first end member 12, as shown in Figures 1-8. First and second coupling or connection mechanisms 22, 24 can be provided at distal or free ends of the first end member 12 and the second end member 14, respectively, as shown in Figures 1-7, 10, and 11.

[0033] As shown in Figures 1-6, the first end member 12 comprises a tubular or cylindrical strut body with or defining an internal cavity extending axially from an end portion of the first end member 12 opposite the first fitting 22. Also shown in Figures 1-6, the first end member 12 includes an axially extending slot 40 in the strut body that communicates with the internal cavity. The intermediate member 16 also comprises a tubular or cylindrical strut body with or defining an internal cavity extending axially from an end portion of the intermediate member 16 near the first fitting 22 (and distal from the second fitting 24), as shown in Figures 1-6. The intermediate member 16 is axially slidably or translatably received within the internal cavity of the first end member 12, as shown in Figures 1-6, and extends from / past the end portion of the first end member 12 opposite the first coupling 22. As shown in Figures 1-9, the outer surface of the strut body of the intermediate member 16 may include a surface texture to increase the friction of the outer surface. For example, the outer surface of the intermediate member 16 may include axially spaced circumferential grooves / serrations, a friction coating, or any other roughness or frictional configuration or material.

[0034] 1 and 5-7, the intermediate member 16 can be coupled to (or otherwise comprise) a radially extending pin member / portion 48 that is coupled to a portion of the intermediate member inside the internal cavity of the first end member 12. For example, the pin member 48 can be fixedly coupled to an end portion of the intermediate member 16. The pin member 48 is disposed / received within the slot 40 of the first end member 12 such that the intermediate member 16 is axially slidably received along / within the internal cavity of the first end member 12 but rotationally fixed. This allows the intermediate member 16 to be axially telescopically coupled to but rotationally fixed to the first end member 12.

[0035] As shown in FIGS. 6 and 7 , the pin member 48 can also be connected to the threaded rod 18 to provide a rotationally and axially fixed connection between the threaded rod 18 and the intermediate member 16. For example, the pin member 48 can be fixedly connected to a distal portion of the intermediate member 16. As shown in FIGS. 6 and 7 , the intermediate member 16 can include a sleeve, spacer, collar, or the like 50 disposed radially within a cavity therein between the threaded rod 18 and the inner surface of the strut body (i.e., the outer circumferential wall of the cavity). The sleeve can then radially space (and potentially center) the threaded rod 18 from the wall of the strut body / cavity, thereby enabling the second end member 14 to threadably engage and axially and rotationally translate about the threaded rod 18, as described below. As a result, at least a distal portion of the second end member 16 can be received within the axial cavity of the intermediate member 16 and radially disposed between the threaded rod 18 and the body portion of the intermediate member 16.

[0036] As discussed above, strut assembly 10 includes a first adjustment mechanism on the distal end portion, sleeve, or bushing 42 of first end member 12 that is configured to selectively allow intermediate member 16 to translate freely axially within the axial cavity of first end member 12 and selectively axially fix intermediate member 16 relative to first end member 12. As shown in Figures 1-8, 10, and 11, the first adjustment mechanism of strut assembly 10 includes a first collar, ring, knob, or pivot member 44 that is rotatably threadedly engaged with distal end portion 42 of first end member 12. Distal end portion 42 of first end member 12 may be integral with first end member 12 or may be fixedly connected thereto. The terminal portion 42 may have external threads, and the collar member 44 may have internal threads that mesh with the external threads of the terminal portion 42 so that the first collar 44 translates axially along the terminal portion 42 as the collar member 44 rotates about the second terminal portion 42.

[0037] 7 and 8, the clamping portion of collar member 44 is disposed axially past terminal portion 42 of first end member 12 and includes bearing surface 21. In some embodiments, as shown in FIG. 8, the bearing surface may include a tapered surface, such as a surface that slopes toward the outer surface of the body portion of intermediate member 16 as it extends axially away from first fitting 22 toward second fitting 24.

[0038] 7 and 8, the strut assembly 10 may include a friction or support member 46 radially disposed between the outer surface of the body portion of the intermediate member 16 and the bearing surface 21. In some embodiments, the friction member 46 may include a radially deformable member, such as a radially deformable ring member. In some such embodiments, the support member 46 may include a segmented ring, split ring, or similar member.

[0039] 8 , the first end member 12, collar member 44, and friction member 46 are configured so that, as the collar member 44 advances axially (e.g., by rotation) along the end portion 42 of the first end member 12 toward the first joint 22, the bearing surface 21 of the collar member 44 acts to move toward the friction member 46 and press the friction member 46 radially against the outer surface of the intermediate member 16, applying a compressive / frictional force to the intermediate member (i.e., between the outer surface of the intermediate member 16 and the friction member 46 (and bearing surface 21)). In other words, as the collar member 44 translates axially along the end portion 42 of the first end member 12 toward the first joint 22 (or the end portion of the first end member 12 connected to the first joint 22), the bearing surface 21 presses the friction member 46 radially against the outer surface of the main body portion of the intermediate member 16, axially securing the intermediate member 16 to the first end member 12. Conversely, the first end member 12, collar member 44, and friction member 46 are further moved by axially advancing (e.g., by rotation) collar member 44 along distal end portion 42 of first end member 12 toward second end member 14 and / or second joint 44. , the bearing surface 21 is configured to translate away from the friction member 46 to release the friction member, and as a result, to allow the friction member 46 to move radially away from the outer surface of the intermediate member 16, i.e., not contact the outer surface, and / or not apply (or at least reduce) a compressive force to the outer surface of the intermediate member 16, selectively allowing the intermediate member 16 to translate substantially freely axially within the axial cavity of the first end member 12. In this way, the axial arrangement of the intermediate member 16 and the first end member 12, and consequently the overall axial length of the strut assembly 10, can be easily and quickly roughly selected / configured / adjusted by the user via the collar member 44 (and potentially the engagement of the first end member and / or the intermediate member 16 (or, for example, the second end member 14)), as shown, for example, in the contrast between the arrangement of the strut assembly 10 of the fixation system 100 in Figures 12-16 and the arrangement of the strut assembly 10 of the fixation system 100 in Figures 16-19.

[0040] As discussed above, the strut assembly 10 includes a second adjustment mechanism configured to selectively rotate the second end member 14 relative to the intermediate member 16 and the threaded rod 18 to axially translate the second end member 14 relative to the intermediate member 16 and thereby fine-tune the overall axial length of the strut assembly 10, as shown in Figures 1-7 and 9. As shown in Figures 1-7 and 9, the second adjustment mechanism may be provided on a distal portion of the intermediate member 16 proximal to the second joint 24 (and distal from the first joint 22).

[0041] As further discussed above and shown in FIGS. 6-9 , at least the rod-engaging portion 52 of the axial cavity of the intermediate member 16 (i.e., of the inner surface or wall of the strut body portion of the intermediate member 16 that forms the interior cavity of the intermediate member 16) can be threadably engaged with a threaded rod. In some embodiments, the engaging portion 52 of the intermediate member 16 can be coupled to the inner surface or wall of the strut body portion of the intermediate member 16 that forms the interior cavity of the intermediate member 16, as shown in FIGS. 6-9 . In other embodiments, the engaging portion 52 of the intermediate member 16 can be integral with, i.e., at least a portion of, the inner surface or wall of the strut body portion of the intermediate member 16 that forms the interior cavity of the intermediate member 16.

[0042] 6-9, the engaging portion 52 of the intermediate member 16 includes internal threads, and the threaded rod includes external threads that mate with the internal threads of the engaging portion 52 of the intermediate member 16. In alternative embodiments (not shown), the engaging portion 52 of the intermediate member 16 includes external threads, and the threaded rod includes internal threads that mate with the external threads of the engaging portion 52 of the intermediate member 16.

[0043] As shown in Figures 1-7 and 9, the second adjustment mechanism includes a second collar member 54 that is axially fixed and pivotally coupled to the distal end portion 53 of the intermediate member 16. As shown in Figures 6, 7 and 9, a first portion of the second collar member 54 may extend over and / or around the distal end portion 53 of the intermediate member 16 and be pivotally coupled to and axially fixed thereto. For example, the inner side of the second collar member 54 and the outer side of the distal end portion 53 of the intermediate member 16 may include axially co-located circumferential slots or openings and washers, split rings, O-rings or similar members 56 extending into the slots or openings, as shown in Figures 6, 7 and 9. As a result, the washer or ring member 56 allows the first portion of the second collar member 54 to rotate (about axis X-X) on the end portion 53 of the intermediate member 16, but prevents the second collar member 54 from axially translating (i.e., translating along axis X-X) on the end portion 53 of the intermediate member 16.

[0044] As shown in Figures 6, 7, and 9, the second portion of the second collar member 54 can extend over and / or around the second end member 14 and be pivotally fixed to (i.e., fixedly coupled to) the second end member. In some embodiments, as shown in Figures 6, 7, and 9, the second portion of the second collar member 54 can be coupled to (or otherwise comprise) a radially extending pin member / portion 55. As shown in Figures 2, 3, and 6-9, the outer surface of the strut body portion of the second end member 14 can include an axially extending slot 72 that receives or accommodates the pin member 55 therein. The pin member 55 and slot 72 are configured to allow axial translation of the pin member 55 along the axial length of the slot 72. As a result, the pin member 55 (extending through the slot 72 in the pin member 55 and the second end member) pivotally fixes or fixedly connects the second collar member 54 and the second end member together, but allows the second end member 14 to translate axially relative to the pin member 55, and consequently relative to the intermediate member 16.

[0045] As a result, rotation of the second collar member 54 on and / or around the second end member 14 (i.e., about axis X-X) causes the second end member 14 to rotate within the cavity of the intermediate member 16 and about the threaded rod 18 (i.e., rotate axially within the cavity relative to the intermediate member 16 and threaded rod 18). Because the engagement portion 52 of the second end member 14 and the threaded rod 18 are threadedly engaged, rotation of the second collar member 54 causes the second end member 14 to rotate relative to the threaded rod 18, resulting in axial translation of the second end member 14 relative to the intermediate member 16. In this way, the axial arrangement of the intermediate member 16 and the second end member 14, and consequently the overall axial length of the strut assembly 10, can be easily, quickly, and precisely selected / configured / adjusted by the user via the second collar member 54 (i.e., by rotating the second collar member 54 in a particular angular direction about the axis X-X), as shown, for example, in the comparison between the arrangement of the strut assembly 10 of the fixation system 100 in Figures 12-16 and the arrangement of the strut assembly 10 of the fixation system 100 in Figures 16-19.

[0046] It should be understood that the above description is intended to be illustrative, and not limiting. Numerous modifications and variations can be made herein by those skilled in the art without departing from the overall spirit and scope of the invention as defined by the following claims and their equivalents. For example, the above-described embodiments (and / or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments without departing from their scope. The dimensions and types of materials described herein are intended to define the parameters of the various embodiments, but they are by no means limiting and are merely exemplary. Many other embodiments will be apparent to those skilled in the art upon review of the above description. Therefore, the scope of the various embodiments should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" may be used interchangeably. are used as the plain English equivalents of the terms "comprising" and "wherein," respectively. Furthermore, in the claims that follow: The terms "first," "second," "third," etc., are used merely as labels and are not intended to impose numerical requirements on the objects of such terms. Furthermore, the term "operably connected" is used herein to refer both to connections resulting from the direct or indirect joining of separate and distinct components, and to connections resulting from integrally formed (i.e., monolithic) components. Furthermore, limitations in the following claims are not written in means-plus-function form, and are not intended to be construed under the sixth paragraph of 35 U.S.C. 112 unless such claim limitations clearly use the words "means for" to recite a function without further structure. It is to be understood that not necessarily all of the objects or advantages described above may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or performed in a manner that achieves or optimizes one advantage or group of advantages taught herein, and may not necessarily achieve other objectives or advantages taught or suggested herein.

[0047] While the present invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the present invention can be modified to incorporate any number of variations, modifications, substitutions, or equivalent arrangements not previously described herein, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it should be understood that aspects of the disclosure may comprise only some of the described embodiments. Accordingly, the present invention should not be deemed limited by the foregoing description, but is limited only by the scope of the appended claims.

[0048] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. 1. A strut assembly for an external fixation system, comprising: an elongate first end member having a first end portion, a second end portion, and a first axial cavity extending from the second end portion; an elongate intermediate member having a third end portion, a fourth end portion, a second axial cavity extending from the third end portion, and a threaded rod fixedly connected within the second axial cavity, the intermediate member being pivotally secured within and axially translatable within the first axial cavity of the first end member and extending from the first axial cavity through the second end portion; an elongated second end member having a fifth end portion, a sixth end portion, and a third axial cavity extending from the fifth end portion, wherein at least the fifth end portion of the second end member is received within the second axial cavity of the intermediate member, and the third axial cavity is in threaded engagement with the threaded rod of the intermediate member, the second end member extending from the second axial cavity through the fourth end portion; a first adjustment mechanism at the second end portion of the first end member, the first adjustment mechanism configured to selectively allow the intermediate member to translate freely axially within the first axial cavity and to selectively axially fix the intermediate member relative to the first end member; and a second adjustment mechanism at the fourth free end portion of the intermediate member, the second adjustment mechanism configured to selectively rotate the second end member relative to the intermediate member and the threaded rod to axially translate the second end member relative to the intermediate member; A strut assembly comprising:

2. 10. The strut assembly of claim 1, wherein the first end portion of the first end member comprises a first joint configured to connect to a first external fixation base.

3. 3. The strut assembly of claim 1 or 2, wherein the sixth terminal portion of the second end member comprises a second joint configured to connect to a second external fixation base.

4. 2. The strut assembly of claim 1, wherein the body portion of the first end member includes an axially extending slot, and the intermediate member is pivotally secured and axially translatable within a first axial cavity of the first end member by a first radially extending pin connected to the intermediate member and received within the slot of the first end member.

5. The strut assembly of claim 4 , wherein the first pin is connected to the third end portion of the intermediate member.

6. 6. The strut assembly of claim 4 or 5, wherein the first pin is further connected to the threaded rod to provide a pivotally and axially fixed connection between the threaded rod and the intermediate member.

7. The strut assembly of claim 6 , wherein the first pin is connected to a terminal portion of the threaded rod.

8. 2. The strut assembly of claim 1, wherein at least a fifth terminal portion of the second end member received within the second axial cavity of the intermediate member is radially disposed between the threaded rod and the body portion of the intermediate member.

9. 10. The strut assembly of claim 1 or 8, wherein the third axial cavity of the intermediate member has internal threads and the threaded rod has external threads that mate with the internal threads of the third axial cavity.

10. 2. The strut assembly of claim 1, wherein the second end portion of the first end member comprises external threads, and the first adjustment mechanism comprises a first collar member with internal threads that mesh with the external threads of the second end portion, and wherein rotation of the first collar member about the second end portion causes axial translation of the first collar along the second end portion.

11. 11. The strut assembly of claim 10, wherein the fastening portion of the first collar member is disposed axially past the second end portion of the first end member and comprises a tapered bearing surface, and the first adjustment mechanism further comprises a friction member disposed radially between the outer surface of the body portion of the intermediate member and the bearing surface.

12. 12. The strut assembly of claim 11, wherein axial translation of the first collar along the second end portion toward the first end portion causes the bearing surface of the friction member to radially press against an outer surface of the body portion of the intermediate member to selectively axially secure the intermediate member relative to the first end member.

13. 13. The strut assembly of claim 12, wherein the bearing surface comprises a surface that slopes toward the outer surface of the body portion of the intermediate member as it extends axially away from the second end portion.

14. 14. A strut assembly according to claim 12 or 13, wherein the friction member comprises a deformable ring member.

15. The strut assembly of claim 14 , wherein the deformable ring member comprises a segmented ring or a split ring.

16. 14. A strut assembly according to claim 12 or 13, wherein the outer surface of the body portion of the intermediate member is provided with a surface texture to increase friction.

17. 2. The strut assembly of claim 1, wherein the second adjustment mechanism comprises a second collar member axially fixed and pivotally connected to the fourth end portion of the intermediate member.

18. 18. The strut assembly of claim 17, wherein the body portion of the second end member includes an axially extending slot, and the second collar member is pivotally secured to the second end member by a second radially extending pin coupled to the second collar member and received in the slot of the second end member, such that pivoting of the second collar member about the fourth end portion causes axial translation of the second end member relative to the intermediate member.

19. 1. A bone and / or tissue external fixation system comprising: The first foundation, The second foundation, and a plurality of support posts extending between the first and second bases; It is equipped with A system wherein at least one of the plurality of struts comprises the strut assembly of claim 1 .

20. 20. The bone and / or tissue external fixation system of claim 19, wherein a plurality of the plurality of struts comprises the strut assembly of claim 1.

21. 20. The bone and / or tissue external fixation system of claim 19, wherein each of a plurality of struts comprises a strut assembly according to claim 1.

22. 20. The bone and / or tissue external fixation system of claim 19, wherein the plurality of struts comprises six struts.

23. 23. The bone and / or tissue external fixation system of any one of claims 19 to 22, wherein the first base is configured to be coupled to a first bone and / or tissue of the patient and the second base is configured to be coupled to a second bone and / or tissue of the patient.

24. 23. A strut assembly according to any one of claims 19 to 22, wherein a first end portion of the first end member comprises a first joint configured to connect to a first external fixation base.

25. 23. A strut assembly according to any one of claims 19 to 22, wherein the sixth terminal portion of the second end member comprises a second joint configured to connect to a second external fixation base.

26. 23. A strut assembly as claimed in any one of claims 19 to 22, wherein the body portion of the first end member includes an axially extending slot, and the intermediate member is pivotally fixed and axially translatable within the first axial cavity of the first end member by a first radially extending pin connected to the intermediate member and received in the slot of the first end member.

27. 27. The strut assembly of claim 26, wherein the first pin is connected to the third end portion of the intermediate member.

28. 27. The strut assembly of claim 26, wherein the first pin is further coupled to the threaded rod to provide a pivotally and axially fixed connection between the threaded rod and the intermediate member.

29. 29. The strut assembly of claim 28, wherein the first pin is coupled to a terminal portion of the threaded rod.

30. 23. The strut assembly of any one of claims 19 to 22, wherein at least a fifth terminal portion of the second end member received within the second axial cavity of the intermediate member is radially disposed between the threaded rod and the body portion of the intermediate member.

31. 23. The strut assembly of any one of claims 19 to 22, wherein the third axial cavity of the intermediate member has an internal thread and the threaded rod has an external thread that mates with the internal thread of the third axial cavity.

32. 23. A strut assembly according to any one of claims 19 to 22, wherein the second end portion of the first end member comprises external threads, and the first adjustment mechanism comprises a first collar member with internal threads that engage the external threads of the second end portion, and wherein rotation of the first collar member about the second end portion causes axial translation of the first collar along the second end portion.

33. 33. The strut assembly of claim 32, wherein the fastening portion of the first collar member is disposed axially past the second end portion of the first end member and includes a tapered bearing surface, and the first adjustment mechanism further includes a friction member disposed radially between the outer surface of the body portion of the intermediate member and the bearing surface.

34. 34. The strut assembly of claim 33, wherein axial translation of the first collar along the second end portion toward the first end portion causes the bearing surface of the friction member to radially press against an outer surface of the body portion of the intermediate member to selectively axially secure the intermediate member relative to the first end member.

35. 35. The strut assembly of claim 34, wherein the bearing surface comprises a surface that slopes toward the outer surface of the body portion of the intermediate member as it extends axially away from the second end portion.

36. 36. The strut assembly of claim 35, wherein the friction member comprises a deformable ring member.

37. 37. The strut assembly of claim 36, wherein the deformable ring member comprises a segmented ring or a split ring.

38. 35. The strut assembly of claim 34, wherein an outer surface of the body portion of the intermediate member is provided with a surface texture to increase friction.

39. 23. The strut assembly of any one of claims 19 to 22, wherein the second adjustment mechanism comprises a second collar member axially fixed and pivotally connected to the fourth end portion of the intermediate member.

40. 40. The strut assembly of claim 39, wherein the body portion of the second end member includes an axially extending slot, and the second collar member is pivotally secured to the second end member by a second radially extending pin coupled to the second collar member and received in the slot of the second end member, such that pivoting of the second collar member about the fourth end portion causes axial translation of the second end member relative to the intermediate member.

Images