Abstract:
A bone plating system to aid in tibial rotational osteotomy correction. Also, a method for correcting a long bone that has an angular misalignment.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 60/985,448, filed Nov. 5, 2007, all of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Various embodiments of the present invention pertain to methods and apparatus for correction of an angular misalignment in a bone, and in particular to a system of plates that supports both sections of a cut bone in which the angle has been corrected. 
       BACKGROUND OF THE INVENTION 
       [0003]    Angular misalignment of a long bone such as a tibia can result in a permanent toeing-in position of the foot, sometimes referred to pigeon toe. This condition can be corrected by surgery. Currently, surgeons will drill two pins into the bone then cut the tibia in two. Once cut, they rotate the bone while observing the pin locations. Once the desired rotation is achieved, they couple the two pieces of bone together with a single plate that extends across the cut, with the intent of not changing the desired rotation. 
       SUMMARY OF THE INVENTION 
       [0004]    One aspect of some embodiments of the present invention pertain to a tibial plating system for use in performing rotational tibial osteotomies. 
         [0005]    Yet another aspect of some embodiments pertain to a method that uses two primary plates that are aligned and screwed into place prior to cutting the tibia. Once the primary plates are screwed into place, the tibia is cut. This allows the surgeon to rotate the tibia to make the correction. After rotation, a secondary plate is fastened to each primary plate to maintain the correction. 
         [0006]    Yet another aspect pertains to an orthopedic plating system that includes first and second primary plates attached to a long bone. These plates are interconnected by a secondary plate that is curved about a first axis generally parallel to the longitudinal axis of a long bone, and further curved about a second axis that is at least partly orthogonal to the first axis. 
         [0007]    It will be appreciated that the various apparatus and methods described in this summary section, as well as elsewhere in this application, can be expressed as a large number of different combinations and subcombinations. All such useful, novel, and inventive combinations and subcombinations are contemplated herein, it being recognized that the explicit expression of each of these myriad combinations is excessive and unnecessary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0008]      FIG. 1  shows a representation of a method of repairing a bone according to one embodiment of the present invention. 
           [0009]      FIG. 2  represents a succeeding part of the method begun in  FIG. 1 . 
           [0010]      FIG. 3  represents a succeeding part of the method begun in  FIG. 1 . 
           [0011]      FIG. 3   a  is a cross sectional view of the aligned bone portions as viewed from line  3   a - 3   a  of  FIG. 3 . 
           [0012]      FIG. 4  is a frontal view of a secondary plate according to one embodiment of the present invention. 
           [0013]      FIG. 5  is a view of the plate of  FIG. 4  as taken along line  5 - 5 . 
           [0014]      FIG. 6  is a view of the plate of  FIG. 4  as taken along line  6 - 6 . 
           [0015]      FIG. 7  shows frontal, side, and top views of a primary plate according to one embodiment of the present invention. 
           [0016]      FIG. 8  shows frontal, side, and top views of a primary spacing device according to one embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0018]    The use of an N-series prefix for an element number (NXX.XX) refers to an element that is the same as the non-prefixed element (XX.XX), except as shown and described thereafter. As an example, an element  1020 . 1  would be the same as element  20 . 1 , except for those different features of element  1020 . 1  shown and described. Further, common elements and common features of related elements are drawn in the same manner in different figures, and/or use the same symbology in different figures. As such, it is not necessary to describe the features of  1020 . 1  and  20 . 1  that are the same, since these common features are apparent to a person of ordinary skill in the related field of technology. Although various specific quantities (spatial dimensions, temperatures, pressures, times, force, resistance, current, voltage, concentrations, wavelengths, frequencies, etc.) may be stated herein, such specific quantities are presented as examples only, and are not to be construed as limiting. 
         [0019]    Various embodiments presented herein pertain to methods and apparatus for correcting an angular offset in a bone, such as a tibia or other long bone. Some embodiments include attachment and coupling plates that are sized for pediatric patients. In pediatric applications, the system of plates described herein are preferably not placed across the growth plate of the bone, so as to not interfere with bone growth in the patient. However, other embodiments of the present invention contemplate attachment of plates to the bone at any location. Further, other embodiments of the present invention are adapted and configured to couple to adult bones. 
         [0020]      FIGS. 1 ,  2 , and  3  depict the installation of the apparatus shown in  FIGS. 4 ,  5 ,  6 ,  7  and  8 . Referring first to  FIG. 7 , a primary plate  30  is shown according to one embodiment of the present invention.  FIG. 7  presents a primary plate  30  shown in three orthogonally projected views. Plate  30  can be of relatively constant thickness and in some embodiments having a concave side  36  that is curved to improve its contact with the surface of a bone. 
         [0021]    Plate  30  in some embodiments includes a pair of attachment holes  34   a  and  34   b . Attachment holes  34   a  and  34   b  are adapted and configured to permit plate  30  to simultaneously interface with the bone on the concave side  36  and also interface with a secondary plate  40  on the convex side  38 . In some embodiments, at least one of holes  34   a  or  34   b  extend through the thickness of plate  30  to permit the insertion of a bone anchor therethrough. In some embodiments, both holes  34   a  and  34   b  are through holes. In yet other embodiments, the other one of holes  34   a  or  34   b  are blind holes that are threaded to accept a fastener for securement of secondary plate  40 . 
         [0022]    The present invention contemplates producing primary plate  30  from any material suitable for inclusion in an animal body, and including as examples titanium and stainless steel. 
         [0023]      FIGS. 4 ,  5 , and  6  depict front and top views, respectively, of a secondary plate  40  according to one embodiment of the present invention. In one embodiment secondary plate  40  comprises an upper portion  42  and lower portion  44  interconnected by a central portion  48 . Upper portion  42  includes one or more attachment holes  46   a  and  46   b , and lower portion  44  includes one or more attachment holes  46   c  and  46   d . Attachment holes  46   a  and  46   b  are adapted and configured for coupling of upper portion  42  to a primary plate  30 , as will be described later. Attachment holes  46   c  and  46   d  are adapted and configured for coupling to a primary plate  34  that will be described later. 
         [0024]    In one embodiment, secondary plate  40  is of a relatively constant thickness. However, the present invention also contemplates those embodiments in which the upper portion  42  has a first thickness, lower portion  44  has a second thickness, and the first and second thicknesses are different. This difference in thicknesses can accommodate particular bone geometry after rotation of the bone portions. Yet other embodiments of the present invention contemplate a secondary plate  40  having a variable thickness from upper portion  42  to lower portion  44 . 
         [0025]    As best seen in  FIG. 5 , secondary plate  40  includes a central portion  48  that is curved about an axis  68  that is substantially parallel to the longitudinal axis of a long bone. Therefore, the central axes of holes  46   a  and  46   b  are nonparallel to the central axes of attachment holes  46   c  and  46   d.  This curvature about axes  68  results in an included angle  52  (as projected into a plane perpendicular to axis  68  and parallel to axis  69 ). Secondary plate  40  thereby “wraps around” the longitudinal axis  68  of a long bone. 
         [0026]    In some embodiments secondary plate  40  includes a central portion  48  that is curved about a lateral axis  69  that is substantially perpendicular to longitudinal axis  68 . As best seen in  FIG. 6 , one of attachment holes  46   c  or  46   d  has a central axis that is nonparallel to the central axis of one of holes  46   a  or  46   b.  In some embodiments, there is an included angle  54  that indicates a degree of curvature of central portion  48  about lateral axis  69 . Included angle  54  is shown as projected into a plane that is perpendicular to axis  69  and parallel to axis  68 . 
         [0027]    In yet other embodiments, secondary plate  40  is curved about axis  68  and also curved about axis  69 . In these embodiments, this dual curvature is useful in providing a secure coupling between a pair of primary plates attached to a bone. 
         [0028]    Although what has been shown and described are included angles  52  and  54  as established by the central axis of attachment holes, the present invention also contemplates those embodiments in which the angles  52  and  54  are defined from a first projection normal to the interior, primary plate-contacting surface  41  of upper portion  42  relative to second projection normal projected from the interior, primary plate-contacting surface  41  of lower portion  44 . 
         [0029]    Yet other embodiments of the present invention contemplate a kit  100  that includes a plurality of secondary plates with varying amounts of curvature. As one example, kit  100  includes a plurality of secondary plates such as plate  40  that are curved so as to have an included angle  52  ranging from 5 degrees to 90 degrees in predetermined increments, such as 5 degree increments. In yet other kits contemplated by the present invention each of the previously described incremental families (such as the family having an included angle  52  of 30 degrees) includes its own subfamily of secondary plates that have this same included angle  52 , but are also curved to have an included angle  54  from 0 degrees to 20 degrees in predetermined increments, such as 2 degrees. 
         [0030]    In some embodiments, a kit  100  further includes at least a pair of primary plates. In some embodiments, primary plates  30  and  32  are identical. In yet other embodiments, kit  100  includes a plurality of primary plates, each having a different thickness. In yet other families, the pair of attachment holes is moved 90 degrees, referring to  FIG. 7 , so that relative to the convex curvature of the bone-contacting side, the attachment holes are side-by-side laterally. 
         [0031]      FIG. 8  depicts a shim or spacing device  80  according to one embodiment of the present invention. In one embodiment, spacing device  80  has a substantially uniform thickness  82 . Further, spacing device  84  includes one or more through holes. In some embodiments, a spacing device  80  can be placed between a primary plate  30  and the bone undergoing surgery. In yet other embodiments, spacing device  80  is placed between the outer coupling surface  38  of plate  30  and the inner coupling surface  41  of secondary plate  40 . Yet other embodiments of kit  100  include a plurality of spacing devices  80  from about 0.05 inches to about ¼ inch in predetermined increments such as increments of 0.05 inches. 
         [0032]      FIGS. 1 ,  2 , and  3  depict a method and use according to one embodiment of the present invention. Referring to  FIG. 1 , a pair of primary plates  30  and  34  are fastened to a bone. In one embodiment, plate  34  is identical to plate  30 , although other embodiments of the present invention contemplate primary plates  30  and  34  that differ with regards to size, shape, thickness, material, surface finish, and the like. 
         [0033]    Primary plates  30  and  34  are fastened to a bone  60  preferably by a bone anchor adapted and configured for secure attachment to the structure of a bone. The plates are installed along either side of a plane of the bone that is to be cut apart. Plates  30  and  34  are spaced apart by a sufficient distance at least to accommodate the thickness of the saw blade. 
         [0034]    Referring to  FIG. 2 , after the cut the top primary plate  30  is attached to the upper portion of bone  60  and lower primary plate  30  is attached to the lower portion of the bone. The upper and lower portions of the bone are then rotated relative to each other to a new angular relationship. After the proper angular relationship is achieved, a secondary plate  40  is coupled so as to create a fixed relationship between primary plates  30  and  34  (as best seen in  FIG. 3 ). 
         [0035]    Various embodiments of the present invention contemplate different ways of coupling the secondary plate to the primary plate so as to fix the angular relationship of the upper and lower bone portions. Further, various embodiments of the present invention contemplate that the upper and lower primary plates  30  and  34  couple in the same manner to secondary plate  40 , whereas other embodiments contemplate that plates  30  and  34  will be coupled to secondary plate  40  in different ways. 
         [0036]    As one example, a primary plate is fastened to the bone by a bone anchor. A second fastener then couples the primary plate to the secondary plate. In such an embodiment, the primary plate would have one through hole and one threaded hole, and the secondary plate would have at least one through hole that aligns with the threaded hole of the primary plate. 
         [0037]    As another example, the primary plate includes a through hole for fastening to the bone, and further includes a threaded stud that, after assembly, extends through a hole in the secondary plate, after which coupling is achieved by means of a nut. Preferably, the secondary plate includes a recessed portion surrounding the through hole to accommodate the thickness of the nut. 
         [0038]    In yet another embodiment, the primary plate and secondary plate have their relative positions established by the coaction of an alignment pin extending from one of the plates and received within a blind hole of the other plate. in such embodiments, it is further possible to include a fastener that couples the primary plate and the second plate, such as a bolt in a threaded hole or a threaded shaft and a nut. 
         [0039]    In yet other embodiments, the bone anchor that couples the primary plate to the bone is removed prior to installation of the secondary plate. The secondary plate includes a through hole that is aligned with the hole and the primary plate and the hole and the bone, and a bone anchor couples the secondary plate and primary plate to the bone proximate (and underneath) to the primary plate. 
         [0040]    In yet other embodiments, the bone anchor that couples the primary plate to the bone is not firmly attached until the primary and secondary plates have been aligned. In yet other embodiments, the bone anchor is loosened to permit rotation of the primary plate about the anchor. With a loose primary plate, the primary plate and the secondary plate can be changed in their relative alignment, after which the primary plate can be tightened to the bone. 
         [0041]    Yet other embodiments of the present invention contemplate mixing of the various attachment methods discussed herein. 
         [0042]    While the inventions have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.