Abstract:
A fixator for use in the reconstruction of acute, chronic and traumatic injuries to the upper and lower extremities. The fixator has a unique clamping system that allows for the snapping in of pins and rails, and for multi-planar fixation of bones.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. patent application Ser. No. 13/937,772, filed Jul. 9, 2013, which is a continuation of U.S. patent application Ser. No. 13/551,185, filed Jul. 17, 2012 (now U.S. Pat. No. 8,486,069), which is a continuation of U.S. patent application Ser. No. 12/643,371, filed Dec. 21, 2009 (now U.S. Pat. No. 8,235,994), which is a continuation of U.S. patent application Ser. No. 11/368,783, which was filed on Mar. 6, 2006 (now abandoned) claiming priority to U.S. Provisional Patent Application No. 60/659,227, filed on Mar. 7, 2005, the entireties of which are incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to external fixation devices, and more particularly to an external fixation device for use in the reconstruction of acute, chronic and traumatic injuries to the upper and lower extremities. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the medical field, patients can suffer from acute, chronic, and/or traumatic injuries to the upper and lower extremities. In such circumstances, it is often desirable to stabilize and reconstruct the bones of the afflicted area. To that end, systems have been developed to help stabilize and reconstruct injured bones. One type of system employed in the past is an external fixation system. 
         [0004]    All bone injuries are not the same. As a result, the best mode of treatment for a bone injury can vary significantly depending on the size of the person, size of the injured bone, and type of bone injury. Specifically, it is often times desirable to have an external fixation device that is capable of accommodating a wide variety of pin placements. However, it is simultaneously desirable to have a relatively simple system that can be readily taught to practitioners in the field. Further, it is also necessary to have a stable system that effectively treats the bone injury. Finally, it is desirable to have a cost effective system. It is therefore desirable to have an external fixation device that allows for versatile pin placement, is relatively simple, stable, and cost effective. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention comprises an external fixation device (“fixator”) for use in the reconstruction of acute, chronic and traumatic injuries to the upper and lower extremities. The fixator&#39;s functions include, but are not limited to, immobilization, compression, joint realignment, arthrodesis, bone distraction and lengthening, fracture reduction/stabilization, and treatment of Charcot arthropathy. More specifically, potential uses for the fixator include acute stabilization and chronic reconstruction of bones, particularly those of the hand or foot. Advantages of using the fixator include, but are not limited to, the ability to gradually correct over time, to fixate away from the injury site if necessary, to provide additional manipulation or additional correction, and to provide assistance in interpositional bone grafting. 
         [0006]    The fixator can be used in multi-planar and multi joint correction, is percutaneous and, therefore, minimally invasive, and can provide additional stability and mobility when compared to fixation devices currently in use. Additional advantages of the present invention over existing devices include the design and adjustability to easily assemble and disassemble components of the system without disturbing pins already set into the patient&#39;s bone or the rest of the system itself. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The drawings may not be to scale. The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which: 
           [0008]      FIG. 1  is a side perspective view of one embodiment of the fixator. 
           [0009]      FIG. 2  is a side perspective view of a second embodiment of the fixator. 
           [0010]      FIG. 3  is a side and top view of one embodiment of a clamp system. 
           [0011]      FIG. 4  is a side view of one embodiment of the fixator. 
           [0012]      FIG. 5  is a top view of one embodiment of the fixator. 
           [0013]      FIG. 6  is an angled view of one embodiment of parts of the clamp system. 
           [0014]      FIG. 7  is a side view of one embodiment of the clamp system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    While the present invention is susceptible of embodiments of various forms, there is shown in the drawings, and will hereinafter be described some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention. It is not intended to limit the invention to the specific embodiments listed. 
         [0016]    As can be seen in  FIGS. 1-7 , in one embodiment of the present invention, a fixator  10  comprises a rail  12 , at least one clamp system  14 , and a pin  16 . Generally, the clamp system  14  is configured to attach to both the rail  12  and the pin  16 , which is connected to the bone  40  for fixation and stabilization. The fixator  10  may further include compression and distraction nuts  18  functionally connected to the fixator  10  to allow for additional manipulation of bone healing and growth. The clamp systems  14  can be splined to receive and hold rails  12  and pins  16 . 
         [0017]    The rails  12  may be any size or shape, and persons of skill in the art will recognize that different application require rails  12  of many differing sizes or shapes, all of which are contemplated herein. The rails  12  may, for example, have a circular, oblong, square, rectangular, or other-shaped cross section. Typically, however, the rails  12  have a round or circular cross-section and are sized in a manner suitable for fixation of small bones  41 , such as those of the foot or hand. The rails  12  may be composed of many materials including, for example, carbon fiber or high density plastic, which allows the rod to be radiolucent. Optionally, the rails  12  may also be threaded to allow for attachment of clamp systems  14 , distraction/compression nuts  18 , or other components of a fixator  10 . 
         [0018]    In one embodiment of the present invention, the rail  12  has a “negative” thread pattern, in which the threads  22  are grooves in the surface of the rail  12  rather than protrusions. In this specification, reference to a threaded component will be a disclosure of both a positive and negative thread. The negative thread pattern allows, for example, the clamp system  14  to easily slide up and down the rail  12 , while still allowing for the attachment of compression nuts  18  or other components which could be threaded onto the rail  12 . In such situations, the corresponding component, such as a compression nut  18 , will have a positive thread pattern. In a preferred embodiment, the rail  12  has a thread pitch of approx 1 mm so one revolution of around the threaded rail  12  produces 1 mm of linear movement. In another embodiment, the rail  12  can be geared. In such an embodiment, the rail has a rack and pinion design  20  that allows for compression or distraction. This geared version can have a scale  24  indicating the amount of compression or distraction. 
         [0019]    As can be seen more specifically in  FIGS. 6 and 7 , in a preferred embodiment, the clamp system  14  comprises a first clamp area  32  and a second clamp area  42 . Preferably, the first clamp area  32  comprises a pin clamp  34  while the second clamp area  42  comprises a rail or bar clamp  44 . Preferably, the first clamp area  32  is functionally connected to the second clamp area  42  such that the object held by the different clamp areas, either pins  16  or rails  12 , can lie in different planes. 
         [0020]    Preferably, the first clamp area  32  is a pin clamp  34  that can comprise a pin clamp top  36 , a pin clamp bottom  38  and a first clamp bolt  40 . The pin clamp top  36  and bottom  38  are each configured to allow the first clamp bolt  40  to pass through them. In one embodiment, the first clamp bolt  40  is threaded, and the pin clamp top  36  and pin clamp bottom  38  have internal, threaded holes configured to receive the threaded first clamp bolt  40 . When held by the first clamp bolt  40 , the pin clamp top  36  and bottom  38  can be thought of as a set that together define at least one pin passage  33  capable of receiving the pin  16 . Preferably, the pin clamp top and bottom  36 ,  38  each have inner surfaces  35  that together define two distinct pin passages  33  each capable of receiving the pin  16 . It is preferred that the inner surfaces  35  of the pin passages  33  be textured to allow for more secure engagement of the pin  16 . For example, the inner surfaces  35  may have a 2× diamond face with grooves 90 degrees to each other. In addition to the inner surfaces  35  being textured, other surfaces of the pin clamp top and bottom  36 ,  38  may be textured where a more secure engagement is desired. 
         [0021]    In one embodiment, the two distinct pin passages  33  are configured to receive the same size pin  16 . In another embodiment, one pin passage  33  is configured to receive one size pin  16 , for example a half pin, while the other pin passage  33  is configured to receive a second size pin  16 , for example a transfixing pin. It is contemplated that the pin passage  33  will extend in a direction substantially perpendicular to the first clamp bolt  40 . In one embodiment, the pin clamp top and bottom  36 ,  38  can be rotated around the first clamp bolt  40  such that the pins  16  can be orientated in any direction in the plane perpendicular to the first clamp bolt  40 . 
         [0022]    In a preferred embodiment, the first clamp area  32  further comprises another pin clamp  34  or a rail clamp  44 . An example of a first clamp area  32  with at least two pin clamps can be found in  FIG. 7 . As can be seen in  FIG. 7 , two sets of pin clamp top and bottom clamps  36 ,  38  can be arranged proximate each other on the pin clamp bolt  40 . In such a set up, four distinct pin passages  33 , each capable of receiving a pin  16 , can be defined by the pin clamp top and bottoms  36 ,  38 . In a preferred embodiment, the first clamp area  32  further comprises springs  46  which are functionally attached to the first clamp area  32  and that exert pressure on some of the pin clamp tops and bottoms  36 ,  38 . In such a configuration, the pin clamps  34  can be “snap in.” That is, one can exert force on the pin clamp top and/or bottom  36 ,  38 . When so doing, the pin clamp top and/or bottom  36 ,  38  will push against the springs  46  and thereby be in a position that defines an opening  48  leading into the pin passage  33  capable of allowing the pin  16  to be pressed into that pin passage  33 . When the force is released, the springs  46  again exert full pressure on the pin clamp top and/or bottom  36 ,  38 , causing the pin clamp top and bottom  36 ,  38  set to clamp on the pin  16  and hold it in a fixed position. In addition, a nut  52  can then be tightened to more securely hold the rail  12  or pin  16  in place. 
         [0023]    In another embodiment, the first clamp area further comprises a rail clamp  44 . The rail clamp  44  comprises a rail clamp top  46 , a rail clamp bottom  47  and a rail clamp bolt  49 . The rail clamp top and bottom  46 ,  47  are each configured to allow the rail clamp bolt  49  to pass through them. In one embodiment, the rail clamp bolt  49  is threaded, and the rail clamp top and rail clamp bottom  46 ,  47  have internal, threaded holes configured to receive the threaded rail clamp bolt  49 . When held by the rail clamp bolt  49 , the rail clamp top and bottom  46 ,  47  can be thought of as a set that together define at least one rail passage  54  capable of receiving the rail  12 . It is contemplated that the inner surfaces  56  of the rail passage  54  can be textured to allow for more secure engagement of the rail  12 . For example, the inner surfaces  56  may have a 2.times. diamond face with grooves 90 degrees to each other. In addition to the inner surfaces  56  being textured, other surfaces of the rail clamp top and bottom  46 ,  47  may be textured where a more secure engagement is desired. As seen in  FIG. 5 , the first clamp area  32  can comprise a rail clamp  44  and a pin clamp  34 . In such cases, the rail passage  54  can be in a different plane than the pin passage  33 . The first clamp area  32  can be configured to allow for the rail  12  in the rail passage  54  to be disposed in a different direction than the pin  16  in the pin passage  33 . For example, the pin  16  may extend at an angle generally perpendicular to the bone or bones  41  to be fixed so that it can be anchored in the bone  41  while the rail  12  may extend at an angle generally parallel to the bone or bones  41  to be fixed. 
         [0024]    In one embodiment, a hinge  60  is attached to the first clamp bolt  40  proximate to either a pin or rail clamp bottom  38 ,  47 . In a preferred embodiment, the hinge  60  has a male element  62  and a female element  64 . The use of the terms male and female elements  62 ,  64  is not meant to suggest a certain structure, but only to disclose that the two elements are configured to work together to provide a hinged connection. The male element  62  has a first section  66  and a second section  68  that are connected to each other. The first section and the second section  66 ,  68  can be disposed at about a  90  degree angle in relation to each other. Preferably, the first section  66  is configured to receive the first clamp bolt  40  by having a hole therethrough. The hole may be threaded. It is also preferred that the surface  69  of the first section  66  proximate the pin clamp  34  be textured. For example, the surface may have a 2× diamond face with grooves 90 degrees to each other. Preferably, the second section  28  is configured to receive a hinge bolt  70  by having a hole therethrough. The hole may be threaded. 
         [0025]    The female element  64  can have a first section  72  that is connected to a second section  74 , preferably at about a  90  degree angle in relation to each other. The first section  72  of the female element  64  is preferably configured to receive a rail clamp bolt  49  by having a hole therethrough. The second section  74  of the female element  64  can have a hole therethrough that is able to accommodate the hinge bolt  70 . The female element  64  is hingedly connected to the male element  62 . In a preferred embodiment, both the female element  64  and the male element  62  are disposed on the hinge bolt  70 , and are held thereon by a hinge retaining washer or nut  76 . When the hinge bolt  70  and retaining washer or not  76  are loose, the female element  64  can be rotated in relation to the male element  62 , and vice versa. To stabilize the connection, the hinge bolt  70  is tightened, thus holding the male element  62  against the female element  64 . The surfaces  78  of the female and male elements  62 ,  64  that come into contact with each other may be textured to increase friction and create a more stable connection. In addition, washers  80  may be employed to ensure a stable connection. 
         [0026]    In a preferred embodiment, the first clamp area  32  is connected via the hinge  60  to the second clamp area  42 . The second clamp area  42  can comprise a pin clamp  34 , a rail clamp  44 , or a combination of pin and rail clamps,  32 ,  44 . Preferably, each clamp system  14  allows for multi-planar attachment of rails  12  and pins  16 . 
         [0027]    In another embodiment, the clamp system  14  comprises one clamp area. In such a system, the one or more pin clamps  32  and one or more rail clamps  34  can be linearly attached to the same bolt  82 . For example, as can be seen in  FIG. 3 , such a clamp system comprises one or more pin clamp tops  36  held in spaced relation to one or more corresponding pin clamp bottoms  38 . Together, the pin clamp top and bottom  36 ,  38  define a pin passage  33  that can accept a pin  16 . The pin clamp tops and bottoms  36 ,  38  are configured with a hole therethrough that accepts a pin clamp bolt  82 . The pin clamp tops and bottoms  36 ,  38  can be loosened and tightened to accept a pin  16  and then securely attach to that pin  16 . This embodiment of a clamp system  14  further comprises a clamp body  84  that preferably is configured with a hole therethrough that can accept the pin clamp bolt  82 . The clamp body  84  can further define a rail passage  86  that is capable of accepting a rail  12 . The clamp body  84  can further comprises a device, such as a bar clamp bolt  88 , that is capable of being screwed into the rail passage  86  to secure the rail  12 . 
         [0028]    The pins  16  can be half pins or transfixing pins. In practice, one part of the pin  90  is set into a patient&#39;s bones while a second part of the pin  92  is attached to a clamp area  32 ,  42 . The configuration of the fixator  10  allows for such pins  16  to be placed prior to, during, or after assembly of the other parts of the fixator  10  without comprising the accuracy of the fixation. 
         [0029]    As can be seen in  FIGS. 1 ,  2 ,  4 , and  5 , it is contemplated that the fixator  10  comprise more than one clamp system  14 . A first clamp system  14  is preferably attached to a bone  41  at a first location. A second clamp system  14  is preferably attached to a bone  41 , either the same bone, or a different bone, at a second location. The two clamp systems  14  are connected by a rail  12 , to which both clamps systems  14  are attached via the rail clamp  44 . More than one clamp system  14  and more than one rail  12  can be utilized. In one embodiment, a first clamp system  14  has a rail clamp  44  attached to a first rail  12  and a pin clamp  34  attached to two pins  16 . The pins  16  are attached to a bone  41  at a first location. A second clamp system  14  has a rail clamp  44  attached to the first rail  12 , and a pin clamp  34  attached to two different pins  16 , which are attached to a bone  41  at a second location. The second clamp system  14  also has a second rail clamp  44  attached to a second rail  12 . A third clamp system  14  has a rail clamp  44  attached to the second rail  12  and a pin clamp  34  attached to two pins  16 . These two pins  16  are attached to either the same bone  41 , or a different bone. As can be seen, the fixator  10  described herein, with each clamp system  14  capable of being comprised of one or more adjustable rail or pin clamps  44 ,  34 , allows for a wide range of fixator  10  configurations that allow for effective treatment of a number of injuries. 
         [0030]    The clamps systems  14  are adjustable with respect to the rail  12  in that each clamp system  14  can slide up or down the rail  12  and also rotate around the rail  12  freely. Once the optimum position for each clamp system  14  is obtained, the clamp system  12  may then be fixed securely in place by simply tightening the rail clamp  44 . Moreover, additional clamp systems  14  may be added to or removed from the fixator  10  easily, both prior to fixation and stabilization and at any point during the healing process, and any number of rail or pin clamps  44 ,  34  may be used, depending upon the number of rails or pins  12 ,  16  necessary for a given treatment. 
         [0031]    The pins  16  can be placed independently of the fixator  10  because of the snap-in functionality of the clamp systems  14  and the ability of the fixator  10  to correct in all planes due to the multi-planar movement of the clamp systems  14 . 
         [0032]    In a further embodiment of the present invention, compression nuts and distraction nuts  18  can attached to the rails  12  and used in conjunction with the clamp systems  14  to further adjust bone healing and growth. The nuts  18  may be used to move the clamp systems  14  incrementally along the rail  12  without moving the pins  16  or other components of the fixator  10 , thus providing additional correction on a minute scale during the healing or growth process. The compression nuts  18  are preferably attached on the rail  12  such that, when moved, they will force two clamp systems  14  to move closer to each other. The distraction nuts  18  are preferably attached on a rail  12  between two clamp systems  14  such that when the distraction nut  18  is moved, it will force one clamp system  14  away from the other. Preferably, more than one compression and or distraction nuts  18  can be attached to the same rail  12  to allow for compression or distraction, i.e., the movement of one or more than one clamp systems  14  in either direction along the rail  12 . Optionally, the compression and distraction nuts  18  may have built in washers. Further, the compression and distraction nuts  18  may have a positive thread and can be used in conjunction with a round rail  12  having a negative thread, as described previously. 
         [0033]    In a further embodiment of the present invention, the fixator  10  may be easily modified in many ways, such as for example to accommodate pins  16  of multiple diameters and lengths. Additionally, many various sizes and shapes of clamps systems  14 , rails  12 , and/or compression/distraction devices may be employed without detracting from the spirit of the invention. Clamp systems  14 , pins  16 , and rails  12  can be easily reproduced, for example, for medium and large applications as well, such as for use on long bones of the leg or arm. 
         [0034]    Because of the exceptional adjustability of the fixator  10 , the fixator described herein can be connected to various parts of the foot or other body parts without being limited by the configuration of the device. Further, the clamp systems  14  also have the mechanical ability to interconnect with other rails and fixation systems, allowing for multiple-rail systems or more complex applications. 
         [0035]    In further embodiments of the present invention, for example, the fixator can be used in conjunction with foot plate (“U ring”) attachments, wires, Ilizarov fixators, or any other compatible external fixator device (none of which are shown) through the use of pins, wires (not shown), and/or transfixing pins. 
         [0036]    The fixator  10  can be comprised of a wide variety of materials. In a preferred embodiment, the components of the fixator  10  are composed of anodized aluminum, stainless steel, or composite polymer. Specifically, the pins  16  can be manufactured from 316L stainless steel and are preferably 2 mm, 2.5 mm, or 3 mm in length.