Patent Publication Number: US-2015080967-A1

Title: System for making a bone repair

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority from earlier filed U.S. Provisional Patent Application No. 60/972,029, filed Sep. 13, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to a method and system for use in the positive and secure positioning of fractured bones. More specifically, the present invention relates to double plate assembly for use in repairing bone fractures that demonstrates improved stability when buttressing fractures that exhibit complex articular patterns and comminution. 
     The human skeleton consists of 206 individual bones that cooperate to perform a variety of important functions such as support, movement, protection, storage of minerals, and formation of blood cells. The bones within the skeleton are generally grouped into two categories, the axial skeleton and the appendicular skeleton. The axial skeleton includes 80 bones that make up the body&#39;s center of gravity and the appendicular skeleton includes the remaining 126 bones that make up the body&#39;s appendages. 
     When a person suffers a bone injury such as a bone fracture, it is important that the fractured bone be repaired promptly and properly. When such a fracture is severe enough, repair often requires remedies that may include surgical intervention. The typical treatment for a fractured bone involves the use of a fixation device that serves to reinforce the fractured bone and keep the adjacent portions of the bone aligned during healing. A wide variety of fixation devices are employed to maintain bone alignment. Further, these bone fixation devices take a variety of forms, including external devices such as casts and internal devices such as bone plates and screws. As can be appreciated by one skilled in the art, bone repairs employing external devices are minimally invasive, allowing reduction and fixation of simple fractures from outside the body. In contrast, bone plates are internal devices that mount directly to bone to span and support the fracture and require a fairly invasive process for placement and installation thereof. 
     While most bones in the skeleton are susceptible to injury or fracture, the repair method used depends on the location of the bone and the proximity of the break to a joint. Further, some bones require a more precise repair as compared to others in order to insure stability of the joint. For example, the radius is one of two long bones found in the human forearm. Distal fractures of the radius are a common result of forward falls, with the palms facing downward, particularly among the elderly. In such falls, force exerted on the distal radius at impact frequently produces dorsal displacement of one or more bone fragments created distal to the fracture site. Unfortunately, internal fixation of such dorsally displaced bone fragments using bone plates has proved problematic. Using dorsal fixation, a surgeon may apply a reducing force on the fracture by attaching a bone plate to the dorsal side of the radius. However, unless the bone plate has a very low profile, dorsal tendons overlying the bone plate may rub against it, producing tendon irritation or even tendon rupture. 
     Alternatively, fixation may be performed volarly. In this approach, a surgeon may attach a bone plate to the volar side of the radius. The volar side of the radius may be more accessible surgically and defines a distal pocket in which the distal portion of the bone plate may be disposed. Accordingly, the bone plate may be less obtrusive and its placement at this location may produce less tendon irritation, even if the bone plate is thicker and sturdier. However, while volar fixation provides advantages as compared to dorsal fixation, there are settings where a single volar or dorsal implant does not provide enough stability to provide reliable support for the bony structures. This is particularly problematic in elderly patients that generally have poor quality bone or in high-speed injuries with highly comminuted fracture patterns. In these situations, bone screws used for fastening the plate in place are inserted through openings in the plate. The difficulty is that when the screws are installed into the distal radius, they may not find sufficient bone structure to hold distal bone fragments in position against the bone plate. In addition, it should be appreciated by one skilled in the art that this scenario is not unique to distal radius fractures. It also happens, for example, in distal humerus, proximal olecranon, distal ulna, proximal tibia and distal tibia (pilon) injuries when in certain situations it is necessary to use double plates in order to provide the best mechanical construct. 
     Therefore there is a need for an alternative strategy for reducing and fixing bone fractures that exhibit complex articular patterns and comminution. There is a further need for a method and system that retains the fractured portions of bone in a rigid structure that does not rely on fastening directly to the bone itself for reducing and fixing the bone fracture 
     BRIEF SUMMARY OF THE INVENTION 
     In this regard, the present invention provides a method and system for making a bone repair that is useful in repairing bone fractures at fracture locations where high levels of stability are required. Generally, the present invention is directed to a bone repair system that employs two plates to buttress a fracture from both the dorsal and volar sides and a method of employing the system to achieve an effective bone repair. The plates are affixed to one another using screws that are installed from a volar plate, through the bone and into a dorsal plate. The use of these complimentary dorsal and volar plates creates a highly stable repair structure while requiring fewer screws as compared to the prior art. 
     In one preferred embodiment of the present invention two bone plates are employed on opposing sides of the bone that has suffered a fracture that must be buttressed. Depending on the extent and severity of the fracture being buttressed, the method and system of the present invention may employ two full plates extending along opposing sides of the bone or a full plate on the volar side of the bone and at least one partial plate on the dorsal side. Generally, the object of the present invention is to provide a volar plate that spans and buttresses the fracture while providing at least one secondary dorsal plate that provides support into which the bone screw extending upwardly from the volar plate engages thereby eliminating the need to anchor the bone screw in the bone structure itself. 
     By installing the bone plates of the present invention, fixation of the bone fragments is achieved using screws that engage both the dorsal and volar plates in a manner that rigidly maintains the plates in position relative to one another and the bone to be repaired without requiring that the fasteners engage with the bone itself. This allows the method and system of the present invention to be particularly useful in applications where the fractures is particularly severe, exhibiting complex articular patterns and comminution and applications where the fasteners cannot be reliably fastened into the bone itself. 
     Additionally, the method provided in the present invention provides for the insertion of a first Kirschner wire (K-wire) for temporary reduction and fixation of the fracture. Installation of at least a first bone fixation plate using the installed K-wires for alignment. Installation of at least a second partial bone plate adjacent the bone to be repaired and opposite the first bone plate. Installation of fasteners that fasten the two opposing bone plates to one another such that the fasteners rigidly engage both of the bone plates. 
     It is therefore an object of the present invention to provide a method and system for reducing and fixing bone fractures that exhibit complex articular patterns and comminution. It is a further object of the present invention to provide a method and system that retains the fractured portions of bone in a rigid structure that does not rely on fastening directly to the bone itself for reducing and fixing the bone fracture. 
     These together with other objects of the invention, along with various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
         FIG. 1  is a perspective view of the system of the present invention installed about a bone; 
         FIG. 2  is a cross-sectional view of the system of the present invention along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the system of the present invention along line  2 - 2  of  FIG. 1  depicting an alternate dorsal plate; 
         FIG. 4  is an illustration of various fasteners and locking aperture configurations that may be employed in the context of the present invention; 
         FIG. 5  is a guide device employed in the bone repair system of the present invention; and 
         FIGS. 6   a - 6   d  are illustrations showing the method of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now referring to the drawings, the bone repair system of the present invention is shown and generally illustrated at  FIGS. 1-5  while the method of the present invention is depicted at  FIG. 6 . Generally, the present invention is directed to a bone repair system that employs two complimentary opposing plates to buttress a fracture from both sides of a bone. In one example, in a repair involving a wrist fracture, the plates are affixed to one another using screws that are installed from a volar plate, through the bone and into the dorsal plate. The use of these complimentary volar and dorsal plates creates a highly stable repair structure while requiring fewer screws thereby minimizing the degree of soft tissue dissection. 
     Turning now to  FIG. 1 , in the preferred embodiment of the present invention two complimentary opposing bone plates  2 ,  4  are employed on opposing sides of the bone  6  having the fracture  8  to be buttressed. While the bone  6  to be repaired as depicted in  FIG. 1  is the radius, one skilled in the art can appreciate that the method and system of the present invention is equally applicable to a number of bones throughout the body and accordingly, the teachings of this invention are not limited to the repair of the radius but are equally applicable to any fracture that requires a high stability repair. Generally, the object of the present invention is to provide a first plate  2  that spans and buttresses the fracture while providing at least one secondary plate  4  that provides support into which the bone screw extending upwardly from the volar plate engages, as will be described in detail below, thereby eliminating the need to anchor the bone screw in the bone  6  structure itself. 
     Turning now to the cross-sectional view depicted at  FIG. 2  in connection with  FIG. 1 , it can be seen that the first plate  2  is preferably a full plate installed adjacent the volar side of the bone and includes holes  10  or more preferably slots therein that allow the placement of bone screws  12  therethrough. The holes  10  or slots are configured to allow the shank of the screw  12  to pass yet to engage the head of the screw  12  once the screw  12  is fully installed and tightened. The at least one secondary plate  4  positioned adjacent the dorsal side of the bone includes a hole  14  therein that is particularly configured to receive and engage the threads on the distal end  13  of the screw  12  opposite the head  11 . Upon tightening of the screw  12 , the screw  12  draws the secondary plate  14  against the fractured bone fragment  8  drawing the fractured bone fragment  8  against the first plate  2  and clamping the bone  6  between the two complimentary opposing plates  2 , 4 . 
     The plates  2 , 4  and fasteners  12  may be formed from any medical grade material suitable for permanent placement within the human body including but not limited to titanium, stainless steel, and absorbable materials. Further, it should be appreciated by one skilled in the art that the inner surfaces of the first and second plates  2 , 4  may be provided with an inner surface that is contoured to fit the bone  6  held therebetween. 
       FIG. 3  depicts an alternate cross-sectional view wherein a second plate employed on the dorsal side is actually a pair of partial plates  4   a , 4   b  that are installed at the fastener  12  locations. In this regard, it should be appreciated that the present invention may also be implemented by installing a full plate  2  on the volar side and at least one partial plate  4   a  on the dorsal side or a plurality of partial plates  4   a ,  4   b  on the dorsal side. 
     In the most general sense therefore, referring back to  FIGS. 1-3 , the present invention provides a system for fixation of bone fractures that includes a first plate  2  having a proximal portion  7 , a distal portion  9  and a plurality of apertures  10  formed therethrough, wherein the first plate  2  is configured to be received adjacent a first side of a fractured region  8  in a bone  6 . At least one second plate member  4  is provided wherein the second plate  4  includes at least one aperture  10  formed therethrough, the second plate  4  being configured to be received adjacent a second opposing side of the fractured region  8  in a bone  6 . Finally, a fastener  12  having a proximal end  11  and a distal end  13  is installed through the bone  6  to engage the first plate  2  and second plate  4  via the apertures  10  therein in order to lock the plates  2 , 4  relative to one another and provide stability and support to the fractured region  8 . 
     Turning now to  FIG. 4 , a plurality of fastener configurations  12   a ,  12   b ,  12   c  are depicted that is suitable for use in connection with the present invention. In the most general sense, as depicted in the first fastener  12   a  at the left of  FIG. 4 , the fastener  12   a  is a screw that includes a head  11   a  that engages with the aperture  10  formed in the first plate  2  either using the tapered head or a pan head screw residing in a recess formed in the top surface of the first plate  2  so that the screw head  11   a  does not protrude over the top surface of the plate  2  resulting in irritation of the tissues surrounding the plate  2 . At the distal end  13   a  of the faster  12   a , threads are shown that engage with corresponding threads  15   a  in the aperture  10  formed in the second plate  4 . Again, a fastener  12   a  is employed of the appropriate length such that the distal end  13   a  does not protrude through the surface of the second plate  4 . 
     The second fastener  12   b  depicted at the center of  FIG. 4  shows threads  15   b ,  17   b  on both the head at the proximal end  11   b  of the fastener  12   b  as well as distal end  13   b  of the fastener  12   b  wherein the threads  17   b ,  15   b  on the fastener  12   b  engage corresponding threads formed in the apertures  10  of the first plate  2  and second plate  4 . This allows the plates  2 ,  4  to be engaged with one another and maintained in rigid spaced relation relative to one another despite the condition of the bone at the fractured region. It should be further appreciated that the threading shown and described herein is intended to be of a locking type such as known in the art wherein a differential in the thread pattern on the screw and the thread pattern in the aperture causes the screw to lock relative to the plates once installed and fully tightened. Such locking methods are well known in the art and therefore do not need to be more fully detailed herein. 
     Turning to the fastener  12   c  depicted at the left of  FIG. 4 , the faster  12   c  is shown to be cannulated. In other words, the fastener  12   c  includes a passage  19  therethrough that extends between the proximal  11   c  and distal ends  13   c . Such a passageway  19  allows the screw  12   c  to be installed over a guide such as a Kirchner wire (K-wire) as will be described in more detail below. Further, the distal end  13   c  of the fastener  12   c  is preferably self-drilling to allow it to be installed directly through the bone in accordance with the method as detailed below. 
       FIG. 5  shows a guide device  20  for use in connection with the bone repair system of the present invention. The guide device  20  has a body  22  that includes an alignment tube  24  extending therethrough. The guide tube  24  is positioned adjacent an aperture  10  in the first plate  2 . In addition, the guide device  20  includes a secondary guide element  26  that extends thereform wherein the secondary guide element  26  is positioned in alignment with an aperture  10  in the second plate  4  on the opposite side of the bone  6 . In this arrangement, the guide device  20  holds the first plate  2  and second plate  4  in compression relative to one another and the guide tube  24  is held in alignment such that the longitudinal axis of the guide tube  24  is precisely aligned through the apertures  10  in the first and second plates  2 ,  4 . 
     In terms of a method for repairing a bone fracture, the present invention provides a method for fixation of bone fractures as depicted at  FIGS. 6   a - 6   d . In the most general embodiment of the method, a first plate  2  having a proximal portion, a distal portion and a plurality of apertures  10  formed therethrough is positioned adjacent a first side of a fractured region in a bone  6 , at least one second plate  4  member having at least one aperture  10  formed therethrough is then positioned adjacent a second opposing side of said fractured region in a bone  6 . With the plates  2 ,  4  positioned, the first plate  2  and second plate  4  are secured to one another using at least one fastener  12  having a proximal end and a distal end that engages between one of the apertures  10  in the first plate  2 , through the bone  6  and into one of the apertures  10  in the second plate  4 . 
     More preferably the method includes a step as shown at  FIG. 6   a  wherein a Kirschner wire  28  is installed through the bone. Preferably this installation is accomplished using a guide  20  such as is depicted at  FIG. 5  to precisely align and install the K-wire  28  into the bone. The K-wire  28 , upon installation includes a first end  28   a  extending from one side of the bone  6  and a second end  28   b  extending from an opposing side of the bone  6 . Once the K-wire  28  is installed, the first plate  2  is positioned by aligning one of the plurality of apertures  10  therein about the first end  28   a  of the Kirschner wire  28  (see  FIG. 6   b ). Subsequently, the at least one second plate  4  is positioned about the second end  28   b  of the Kirschner wire  28  (see  FIG. 6   c ). Finally, a cannulated fastener  12  is installed directly over the K-wire  28  such that the fastener  12  is self-drilling and is guided into place about the K-wire  28  (see  FIG. 6   d ). The fastener  12  then engages the first plate  2  and second plate  4  as described above. 
     Alternately, the steps of the method may proceed by first installing a guide device  20  in alignment with a first aperture  10  in the first plate  2  adjacent a first side of the bone  6  such that the guide device  20  secondary guide element  26  is in alignment with a second position on an opposing side of the bone  6 . The guide device  20  is then used to install a Kirschner wire  28  having a first end  28   a  extending from the first aperture  10  and a second end  28   b  extending from said second position on the opposing side of the bone  6 . Next, at least one second plate  4  is positioned by aligning at least one aperture  10  therein about the second end  28   b  of the Kirschner wire  28 . Finally, the first plate  2  is secured to the at least one second plate  4  by installing at least one fastener  12  having a proximal end and a distal end and a cannulated passage extending therebetween, wherein the cannulated passage is installed over the Kirschner wire  28 , such that the fastener  12  installation is directed by the Kirschner wire  28  between the first aperture  10  in the first plate  2 , through the bone  6  and into engagement with the at least one aperture  10  in the second plate  4 . Further, the above process may be accomplished by first positioning the first plate  2  and second plate  4  and aligning the guide device  20  using the apertures  10  therein. 
     Such a system as disclosed within the present invention provides for the application of high rigidity buttressing to fractures without requiring that the screw anchor into the bone fragments themselves. As a result, fewer screws are required to secure fractures exhibiting comminution and higher stability is achieved. 
     It can therefore be seen that the present invention provides a system and method that facilitates the application of high rigidity buttressing to fractures without requiring that the screw anchor into the bone fragments themselves. As a result, fewer screws are required to secure fractures exhibiting comminution and higher stability is achieved. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit. 
     While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.