Abstract:
An orthopaedic bone plate includes a flexible bag having a plurality of through holes; and a hardened polymer within the bag. The bone plate is attached to a bone by placing the bag against the bone; affixing the bag to the bone using a plurality of fasteners which extend through the bag; injecting a polymer into the bag; and hardening the polymer in the bag.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to orthopaedic devices, and, more particularly, to bone plates. 
     2. Description of the Related Art 
     An orthopaedic bone plate is attached to a bone and used to support different bones relative to each other, or support pieces of an individual bone during the healing process. Typically, a bone plate is manufactured to approximate the shape of a bone to which it is to be attached. The shape of the bone plate may be based upon statistical analysis of a common size and shape of a particular bone. However, since the actual size and shape of a bone may vary from one patient to another, it is often times necessary to manually deform the bone plate during surgery to achieve a proper fit. The bone plate may be placed against the bone, observed for deviation, removed from the bone and deformed using manual bending techniques. The bone plate is then placed against the bone and again visualized to determine any further necessary adjustments. This process may be somewhat time consuming during surgery. 
     What is needed in the art is a bone plate which is easy and fast to install, and easily contours to the shape of the bone to which it is attached. 
     SUMMARY OF THE INVENTION 
     The present invention provides an orthopaedic bone plate including a bag, structural support disposed within the bag and high strength polymer surrounding the structural support within the bag. 
     The invention comprises, in one form thereof, an orthopaedic bone plate including a flexible bag having a plurality of through holes; and a hardened polymer within the bag. The bone plate is attached to a bone by placing the bag against the bone; affixing the bag to the bone using a plurality of fasteners which extend through the bag; injecting a polymer into the bag; and hardening the polymer in the bag. 
     An advantage of the present invention is that the orthopaedic bone plate is contourable to the shape of the bone to which it is attached. 
     Another advantage is that a structural support may be positioned within the bag to provide enhanced structural rigidity to the bone plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of an embodiment of an orthopaedic bone plate of the present invention for fixating a spine; 
     FIG. 2 is a side view of the orthopaedic bone plate shown in FIG. 1 attached to the spine; 
     FIG. 3 is a side view of the orthopaedic bone plate shown in FIGS. 1 and 2; 
     FIG. 4 is another embodiment of an orthopaedic bone plate of the present invention; 
     FIG. 5 illustrates yet another embodiment of an orthopaedic bone plate of the present invention; 
     FIG. 6 is a frontal view of a cut tibia to which a bone plate of the present invention may be attached; 
     FIG. 7 is a perspective view of another embodiment of a bone plate shown in relation to the tibia of FIG. 6; 
     FIG. 8 is a front view of the bone plate and tibia of FIG. 7, with the bone plate placed against the tibia; and 
     FIG. 9 is a top view of the bone plate and tibia of FIGS. 7-8, with the bone plate attached to the tibia. 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to FIGS. 1-3, there is shown an embodiment of an orthopaedic bone plate  10  of the present invention which is attached and used to fixate vertebrae  12  in a spine  14 . 
     Orthopaedic bone plate  10  generally includes a flexible bag  16 , a structural support  18  disposed therein and a high strength polymer surrounding structural support  18  and disposed within bag  16 . Bag  16  has a generally H-shape and is configured to fixate three sequentially adjacent vertebrae  12  relative to each other. Bag  16  has a first pair of holes  22 , a second pair of holes  24  and a third pair of holes  26 . Each pair of holes  22 ,  24  and  26  is associated with a respective vertebrae  12  and allows the passage of a fastener such as a bone screw  28  therethrough to attach orthopaedic bone plate  10  to the three associated vertebrae  12 . 
     Bag  16  may be formed from any suitable material. Bag  16  is shown as a contoured bag with a specific H-shape in the embodiment illustrated in FIGS. 1-3. However, the material from which bag  16  is constructed may allow expansion under pressure to some extent. Moreover, bag  16  may be constructed from a porous or non-porous material allowing at least some of the polymer 20 disposed therein to flow or seep therethrough and adhere bag  16  with an adjacent bone. The porous material would provide for the venting of air as the polymer is injected into the bag. 
     Structural support  18  is in the form of a metal, hollow injection tube which is disposed within bag  16 . Injection tube  18  includes an inlet port  30  extending from bag  16 , and four outlet ports  32  which are associated with each respective leg of H-shaped bag  16 . A fill hose  34  is attached with inlet port  30  at one end thereof, and with a source of pressurized polymer (not shown) at an opposing end thereof. Polymer 20 is injected under pressure through fill hose  34  and injection tube  18  to the interior of bag  16  to thus fill bag  16  at a desired fill pressure. 
     Polymer 20 is hardened within bag  16  to form a substantially rigid orthopaedic bone plate  10 . Polymer 20 is a high strength polymer such as PMMA which is curable upon application of energy such as thermal energy, light energy or X-ray energy, or the addition of a chemical catalyst. If bag  16  is constructed as a porous bag, polymer 20 at least partially flows therethrough and may be selected to be bioresorbable. 
     During surgery, the posterior side of spine  14  is exposed for access to the three sequentially adjacent vertebrae  12 . Orthopaedic bone plate  10  is placed over vertebrae  12  as shown in FIGS. 1 and 2. The location of pilot holes  36  on each vertebrae  12  are marked and drilled within vertebrae  12 . Orthopaedic bone plate  10  may either remain in place against vertebrae  12  or be removed from vertebrae  12  during the formation of pilot holes  36 . Bone screws  28  are then passed through each respective hole  22  in bag  16  and threadingly engaged within each corresponding pilot hole  36 . Polymer  20  is then injected under pressure into bag  16  through fill hose  34  and injection tube  18 . Polymer  20  is then hardened within bag  16  either through the application of energy such as thermal energy, light energy or X-ray energy, or the addition of a chemical catalyst prior to or during the injection process. Fill hose  34  is then detached or cut from inlet port  30 . The incision is then closed over spine  14 . 
     Referring now to FIG. 4, another embodiment of an orthopaedic bone plate  40  of the present invention is shown. Orthopaedic bone plate  40  is similar to orthopaedic bone plate  10  shown in FIGS. 1-3 in the sense that it is also used to fixate sequentially adjacent vertebrae  12  relative to each other. Orthopaedic bone plate  40  includes a flexible bag  42  and a pair of structural supports in the form of a pair of injection tubes  44  therein. Each injection tube  44  is disposed within a corresponding projection  46  extending from bag  42 . A pair of fill hoses  48  are attached with each respective injection tube  44 . 
     During surgery, the posterior side of spine  14  is exposed and orthopaedic bone plate  40  is placed adjacent to a pair of vertebrae  12  to be fixated relative to each other. Pilot holes  50  are marked and drilled in each vertebrae  12 . Orthopaedic bone plate  40  is then connected with each vertebrae  12  such that each projection  46  extends into a corresponding pilot hole  50 . A high strength polymer  52  is then injected under pressure into orthopaedic bone plate  40 . Bag  42  is preferably constructed as a porous bag allowing polymer  52  to pass therethrough and thereby bond each projection  46  within the corresponding pilot hole  50 . Polymer  52  is then hardened through the application of energy such as thermal energy, light energy or X-ray energy, or the addition of a chemical catalyst. 
     Referring to FIG. 5, another embodiment of an orthopaedic bone plate  60  of the present invention is shown. Orthopaedic bone plate  60  includes injection tube  64 , projections  66  and fill hoses  68  similar to the embodiment of orthopaedic bone plate  40  shown in FIG.  5 . The primary difference between orthopaedic bone plate  60  and orthopaedic bone plate  40  is that bag  62  includes an accordion shaped interconnecting portion  70  which allows the spacing and angular orientation between projection  66  to vary to some extent, depending upon the exact placement location and orientation of pilot holes  72  in vertebrae  12 . 
     Referring now to FIGS. 6-9, there is shown another embodiment of an orthopaedic bone plate  80  of the present invention which is attached to a bone in the form of a proximal tibia  82 . Tibia  82  has an articular bearing surface  84  which was not in proper alignment with a mating articular bearing surface of a distal femur. Accordingly, a wedge of bone is removed in a procedure known in the industry as a High Tibial Osteotomy. After the wedge is removed the bone surfaces are brought into contact in a known manner. Orthopaedic bone plate  80  is attached to tibia  82  using bone screws  90  which pass through through holes  92  and bag  94  and are threadingly received within pilot holes  96  in tibia  82 . A structural support  98  within bag  94  includes an inlet port  100  allowing a polymer  104  to be injected under pressure through outlet ports  102  in bag  94 . The polymer  104  is then hardened within bag  94 . 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.