Abstract:
An implant operable to alter morphology of a long bone can comprise a first longitudinal member, a second longitudinal member, and an adjusting member. The first longitudinal member can have a bone attachment end and a first connecting end. The second longitudinal member can have a second bone attachment end and a second connecting end. The adjusting member can connect to both of the first and second connecting ends. The adjusting member can be selectively moveable from a first implanted position where the first and second connecting ends are fixed to respective ends of the long bone and spaced apart a first distance to a second implanted position where the first and second connecting ends are fixed to the respective ends of the long bone and spaced apart a second distance. The second distance is less than the first distance causing a long bone to be compressed between the first and second bone attachment ends.

Description:
FIELD 
     The present disclosure relates generally to long bones and more particularly to various implants and methods for reshaping a long bone that may have an unsatisfactory mechanical axis. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     In some examples, a long bone such as a tibia may become misaligned relative to a knee causing cartilage degeneration and/or joint misalignment. In these examples, it may be desired to reshape the bone in an effort to shift the mechanical axis of the bone such as to unload a diseased knee compartment. One known method of correcting various misalignments is an osteotomy that includes cutting the bone and allowing the bone to regrow in the area of the cut. In some examples, a surgeon may cut out a wedge or similar shape to facilitate the realignment and resultant bone growth. In some examples however, cutting the bone in this manner may be unsatisfactory. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     An implant operable to alter morphology of a long bone can comprise a first longitudinal member, a second longitudinal member, and an adjusting member. The first longitudinal member can have a bone attachment end and a first connecting end. The second longitudinal member can have a second bone attachment end and a second connecting end. The adjusting member can connect to both of the first and second connecting ends. The adjusting member can be selectively moveable from a first implanted position to a second implanted position. In the first implanted position, the first connecting end and the second connecting end are fixed to respective ends of the long bone and spaced apart a first distance. In the second implanted position, the first connecting end and the second connecting end are fixed to the respective ends of the long bone and spaced apart a second distance. The second distance is less than the first distance causing a long bone to be compressed between the first and second bone attachment ends. 
     According to additional features, the first bone attachment end can define at least one passage. The second bone attachment end can define at least one passage. The implant can further comprise bone screws that are configured to be received by the respective passages. One of the first and second connecting ends can comprise a first threaded portion. One of the adjusting member or the other of the first and second connecting ends can comprise a second threaded portion. The first and second threaded portions can be configured to threadably mate. The first connecting end can comprise the first threaded portion. The adjusting member can comprise the second threaded portion. The first threaded portion can comprise a male threaded portion and the adjusting member can comprise a female threaded portion. 
     According to other features, the second connecting end can comprise a raised collar that engages a complementary raised flange formed on the adjusting member. The adjusting member can comprise a cylindrical sleeve that has a complementary raised flange. The cylindrical sleeve also comprises the female threaded portion. The complementary raised flange and the threaded portion are both formed on an inner diameter of the cylindrical sleeve. 
     A method of altering morphology of a long bone according to the present teachings can comprise coupling a first bone attachment end of a longitudinal plate to a first portion of the long bone. The long bone can be distracted without fracturing the long bone. A second bone attachment end of the longitudinal plate can be coupled to a second portion of the long bone causing the long bone to be in compression at a first area of the long bone and be in tension at a second area of the long bone. 
     According to additional features of the instant method, distracting the long bone can comprise applying a force onto the second portion of the long bone such that a distance between the first and second portions of long bone changes. Distracting the long bone can comprise applying a force onto the second portion of the long bone such that a distance between the first and second portions is reduced. 
     According to other features of the instant method, coupling the first and second bone attachment ends can comprise advancing bone screws through passages defined through the first and second attachment ends of the longitudinal plate and into the long bone. According to one example, prior to the distracting, the long bone has a first mechanical axis. Subsequent to coupling the second long bone attachment end, the long bone has a second mechanical axis. The first and second mechanical axes are different. 
     A method of altering morphology of a long bone according to another example of the present teachings can include coupling a first bone attachment end of a longitudinal plate to a first portion of the long bone. A securing member can be advanced through an opening in the longitudinal plate and partially into the long bone. The securing member is continued to be advanced into the long bone such that a portion of the securing member slidably engages the longitudinal plate causing the longitudinal plate to be in tension between the first bone attachment end and the opening while concurrently causing a portion of the long bone to be in compression. 
     According to other features of the instant method, coupling the first bone attachment end of the longitudinal plate can comprise advancing at least one bone screw through a passage defined through the first bone attachment end. Advancing the securing member can comprise advancing a screw having a threaded distal end and a conical proximal head. The continuing of the advancing of the securing member can comprise slidably advancing the conical proximal head along the longitudinal plate at the opening. Advancing the conical proximal head can comprise slidably advancing the conical head along a ramp portion defined on the longitudinal plate at the opening. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is an anterior view of an exemplary tibia shown prior to altering its axis (solid line) and subsequent to altering its axis according to the present teachings (phantom line). 
         FIG. 2  is an anterior view of an exemplary right tibia and fibula of an exemplary patient and shown with an implant implanted according to one example of the present teachings. 
         FIG. 3  is a plan view of an implant constructed in accordance to a second example of the present teachings and prior to implantation. 
         FIG. 4  is an anterior view of an exemplary tibia and shown subsequent to implantation of the implant of  FIG. 3 . 
         FIG. 5  is an anterior view of an exemplary tibia shown with an implant constructed in accordance to a third example of the present teachings and shown prior to adjusting an adjusting member of the implant and subsequent to adjusting the adjusting member of the implant. 
         FIG. 6  is an anterior view of an exemplary tibia shown with a pair of implants constructed in accordance to a fourth example of the present teachings and illustrating the implants being placed in tension causing the adjacent bone to therefore be in compression. 
         FIG. 7  is a plan view of an implant shown in  FIG. 6 . 
         FIG. 8  is a cross-sectional view of the implant of  FIG. 7  taken along lines  8 - 8  and shown with a securing member initially driven into the bone. 
         FIG. 9  is a cross-sectional view of the implant of  FIG. 8  and shown with the securing member further advanced into the bone causing a conical head of the securing member to urge a portion of the implant leftward causing the implant to be in tension while concurrently placing the adjacent bone in compression. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
     The following description will be directed toward an implant and method for altering morphology of a long bone. The exemplary description will be directed toward a right tibia  10 . The tibia  10  generally includes a lateral condyle  12 , medial condyle  14 , and medial malleolus  16 . An axis of the tibia  10  is generally defined between a point  20  taken through a horizontal slice of the proximal tibia and a point  22   a  extending through the talus  24 . As viewed in  FIG. 1 , the axis  28  is therefore identified between the points  20  and  22   a . The axis  28  will be referred to herein as an initial axis. The implants and methods according to the present teachings are directed toward realigning this initial axis  28   a  to a desired axis  28   b . The desired axis  28   b  can therefore be defined between the point  20  and a point  22   b . The initial axis  28   a  and the desired axis  28   b  can therefore provide an angle Θ therebetween. It will be appreciated that according to the present teachings, various implants and methods will be described herein where the tibia  10  will be described as being “bent”. The intent however, is not necessarily to reshape the intermediate portion of the tibia  10  to have a bent or bowed contour. The intent is to ultimately change the long axis of the bone and therefore change the angle Θ. 
     Turning now to  FIG. 2 , an exemplary implant  30  will be described. The tibia  10  is shown together with a fibula  32  having a lateral malleolus  34 . In the example shown in  FIG. 2 , the tibia  10  is shown generally before manipulation with the implant  30  in phantom line and after manipulation in solid line. The implant  30  generally comprises a longitudinal member  40  having a first bone attachment end  42  and a second bone attachment end  44 . The longitudinal member  40  can be generally in the form of a plate or rod or other elongated structure. The first bone attachment end  42  defines passages  46  for receiving bone screws  48  therein. Similarly, the second bone attachment end  44  defines passages  50  for receiving bone screws  52  therethrough. 
     In one example of implanting the implant  30 , a surgeon can first bend or deflect the tibia  10  toward a profile suitable to attain the desired axis. In this regard, a surgeon can apply stress to the tibia  10  and fix the tibia  10  while in a stressed or deflected position. In one example, one of the first or second bone attachment ends  42  or  44  can be secured to the proximal or distal tibia with the bone screws  48  or  52 . With one end of the implant  30  secured to the tibia, a surgeon can apply a force at an opposite end of the tibia while concurrently securing the other of the first or second bone attachment end  42  or  44  to the tibia. As can be appreciated, the implant  30  will tend to draw the proximal and distal ends of the tibia toward each other and encourage the tibia  10  to reshape to accommodate this stress as a result of the tibia&#39;s natural remodeling mechanism. It will be appreciated that a series of implants  30  having different lengths can be provided to a surgeon to accommodate tibias of different lengths. It will also be appreciated that in some examples, a surgeon can use a first implant  30  to reshape the tibia to a first position and once the first position is attained, a surgeon can implant another implant  30 , or manipulate the first implant  30  to further encourage the bone to reshape. In other words, the reshaping of the tibia  10  may be conducted with multiple steps. 
     Turning now to  FIG. 3 , an implant  60  is shown. The implant  60  generally comprises a longitudinal member  62  having a main body  64 , a first bone attachment end  66 , and a second bone attachment end  68 . The first bone attachment end  66  can define passages  70  for receiving bone screws  72 . Similarly, the second bone attachment end  68  can define passages  74  configured to receive bone screws  76 . The main body  64  of the implant  60  can generally have an arcuate profile that defines a radius R 1 . 
     Turning now to  FIG. 4 , the tibia  10  is shown prior to implantation of the implant  30  in phantom line and subsequent to implantation of the implant  30  in solid line. Again, in some examples, a surgeon can first secure either the first or second bone attachment end  66  or  68  to the tibia  10 . Next, a surgeon can apply a force to the opposite end of the tibia  10  while securing the other of the first or second bone attachment ends  66  or  68  to the tibia. As shown in  FIG. 4 , the main body  64  of the implant  60  now defines a radius R 2 . In the implanted position, the radius R 2  is greater than the radius R 1 . As can be appreciated, the main body  64  of the implant  60  will tend to want to return to its original radius R 1 . In doing so, the first bone attachment end  66  and the second bone attachment end  68  will tend to urge the respective proximal and distal ends of the tibia rightward as viewed in  FIG. 4  (medially). Concurrently, an intermediate portion of the main body  64  will tend to therefore influence a corresponding intermediate portion of the tibia  10  leftward as viewed in  FIG. 4  (laterally). Again, it will be appreciated that the implant  60  will encourage the tibia  10  to reshape in an effort to realign the axis toward the desired axis  28   b  ( FIG. 1 ). 
     Turning now to  FIG. 5 , an implant constructed in accordance to another example of the present teachings is shown and generally identified at reference numeral  80 . The implant  80  generally includes a first longitudinal member  82 , a second longitudinal member  84 , and an adjusting member  86 . The first longitudinal member  82  generally includes an elongated body portion  92  having a first bone attachment end  94  and a first connecting end  96 . The second longitudinal member  84  can generally comprise a longitudinal body portion  100  having a second bone attachment end  102  and a second connecting end  104 . The first bone attachment end  94  can generally define passages  108  configured to receive bone screws  110  therein. Similarly, the second bone attachment end  102  can define passages  112  configured to receive bone screws  114  therein. While the first and second longitudinal members  82  and  84  are shown as having a generally linear profile, one or both of them can define an arcuate profile. The first connecting end  96  can generally include a threaded portion  120 . The second connecting end  104  can define an annular flange  122  thereon. Those skilled in the art will appreciate that the threaded portion  120  can alternatively be provided on the second connecting end  104  while the raised flange  122  can be provided on the first connecting end  96 . The adjusting member  86  can generally comprise a cannulated cylindrical body  130  having a raised collar  132  and female threads  134  formed thereon. 
     An exemplary method of implanting and using the implant  80  will now be described. Again, the tibia  10  is shown prior to implantation of the implant  80  in phantom line and subsequent to implantation of the implant  80  in solid line. At the outset, a surgeon can attach one of the first or second bone attachment ends  94  or  102  to the tibia. Next, a surgeon may apply a force to the opposite end of the tibia while connecting the other of the first or second bone attachment ends  94  and  102  to the tibia. In another example, a surgeon can attach both of the first and second bone attachment ends  94  and  102  to the tibia  10  without applying an external force onto the tibia  10 . 
     The adjusting member  86  can then be rotated such that the female threads  134  of the cylindrical body  130  threadably advance along the threads  120  on the first connecting end  96 . As can be appreciated, the raised flange  122  on the adjusting member  86  will engage and pull the raised collar  132  (upward as viewed in  FIG. 5 ) on the second longitudinal member  84 . Continued advancement of the adjusting member  86  will tend to urge the respective proximal and distal ends of the tibia toward each other thereby reshaping the tibia  10  and altering the desired axis ( 28   b ,  FIG. 1 ). According to some examples, it may be desirable for a surgeon to advance the adjusting member  86  a first distance along the threads  120  on the first connecting end  96  and allow the tibia to reshape to accommodate such an initial force. Thereafter, a surgeon can then advance the adjusting member  86  further along the first connecting end  96  to encourage the tibia  10  to further reshape. As can be appreciated, one or many adjustment periods may be desired depending on a particular patient. 
     Turning now to  FIGS. 6-9 , an implant  150  constructed in accordance to additional features of the present teachings will be described. The implant  150  generally includes a longitudinal body  152  having a first end  154  and a second end  156 . In one example, the longitudinal body  152  can include a longitudinal plate. The first end  154  generally defines passages  158  configured to receive bone screws  160  therein. The second end  156  can optionally define passages  164  therethrough. The implant  150  can define an opening  170  therethrough. The opening  170  can further be defined by a ramp  172  ( FIGS. 8-9 ). In one example, the opening  170  can define a generally oblong profile. The opening  170  can be configured to receive a securing member  174  therein. The securing member  174  can generally include a distal threaded end  176  and a conical head  178 . 
     An exemplary method of implanting the implant  150  according to the present teachings will now be described. At the outset, a surgeon can secure the first end  154  of the implant  150  to the tibia  10  by advancing the bone screws  160  through the passages  158 . Next, a surgeon can initially locate the securing member  174  into the opening  170  ( FIG. 8 ). The surgeon can then partially advance the distal threaded end  176  into the tibia  10  to a point at which the conical head  178  initially engages the ramp  172  on the body  152  of the implant  150 . Next, the surgeon can further advance the securing member  174  into the bone  10  causing the conical head  178  to slidably advance along the ramp  172  and as a result, urge the implant  150  generally away from the bone screws  160 . In this regard, and as illustrated in  FIG. 9 , advancement of the conical head  178  along the ramp  172  urges the implant  150  leftward. As shown in  FIG. 6 , such an action will cause the implant  150  to generally be in tension illustrated by arrows  180 . As a result, the adjacent tibial bone will be placed in compression identified by the arrows  182 . It will be appreciated that while there are only two implants  150  shown in  FIG. 6 , one or a plurality of implants  150  may be strategically located onto the implant  10  for influencing compression as a desired area. Furthermore, it will be appreciated that while the implant  150  is illustrated as having a particular span, the implant  150  may be suitable for influencing a generally localized compression  182  onto the tibia  10 . In other examples, the implant  150  may be much longer so as to span a greater length of the tibia such that a compressive force  182  can be influenced generally along a greater distance of the tibia  10 . 
     In each of the examples discussed herein, the implants  30 ,  60 ,  80 , and  150  can be removed from the tibia  10  once desirable reshaping of the tibia  10  has occurred. The tibia  10  will tend to remain in the newly reshaped orientation subsequent to removal of the implants  30 ,  60 ,  80 , and  150 . It will also be appreciated that the reshaping may be accomplished sequentially with more than one implant being used such as in succession. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.