Abstract:
An orthopaedic tray trial includes a base plate and at least one movable fastening member attached to the base plate. The fastening member includes a striking element and a bone penetrating pin extending from the striking element. The fastening element may be rotatably attached to the base plate using a hinge pin to connect the striking element to the base plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to an orthopaedic tray trial having at least one attached fastening element. 
     BACKGROUND OF THE INVENTION 
     During knee replacement surgery tibial trials are used to assist a surgeon in preparing the tibial surface for implantation of the tibial portion of the artificial knee. A surgeon uses a tibial tray trial to determine the tibial implant size, to make the appropriate cuts and reams in the bone, and to ensure a proper alignment and tibial component thickness prior to implanting the tibial components. 
     Such a procedure typically entails making an initial tibial plateau cut on the proximal tibial portion of the knee; determining a preferred size tray trial (and ultimately tray implants); placing the selected tray trial over the tibial surface; performing a trial reduction to ensure proper tibial component thickness and alignment; attaching a punch guide to the tibial tray trial; and cutting or reaming the tibial bone through openings in the punch guide and tray trial to prepare it to receive a stem or keel of the tibial implant. During this procedure it is necessary to fix the tray trial to the tibia, at least before cutting or reaming the tibial bone through openings in the punch guide and tray trial. 
     Known tibial tray trials, as illustrated in FIG. 1, typically include a tibial alignment handle  10  is attached to the tibial tray trial  12  to properly locate the trial with respect to a prepared tibia  14 . Pins  16  are then driven through holes in the tray trial to fix the tray trial to the tibia  14 . At least three hands are require to fix tibial tray trial  12  to tibia  14 : one hand holds the tray trial  12  in place using handle  10 ; a second holds a pin  16  in place; and a third hand drives pin  14  through tray trial  12  into tibia  14  to fix the tray trial  12  thereto. 
     One difficulty with the known method for fixing a tibial tray trial to a tibia is that, because it requires more than two hands, a surgeon cannot fix the tray trial without help. Another problem involves the pins themselves. Because the pins must be removed in order to remove the trial to place the permanent prosthesis, they typically include portions that extend above the tray trial to facilitate their removal. However, trialing sometimes involves, particularly when implanting a rotating platform knee tibial prosthesis, moving or rotating a trial insert with respect to the tibial tray trial. When the pins extend above the surface of the tibial tray trial, the pins can prevent relative movement between the tray trial and the trial insert. In addition, pins that are separate from the tray may become lost during surgery, cleaning, or transportation. 
     SUMMARY OF THE INVENTION 
     The present invention provides an orthopaedic tray trial for attachment to a resected bone surface having a base plate and at least one movable fastening element attached to the base plate. The base plate has a bone contacting surface and an opposed working surface. The fastening element includes a striking element and a bone penetrating pin attached to the striking element and extending in a direction from the working surface toward the bone contacting surface of the base plate. 
     The fastening elements may be selectively movable between an open position and a closed position. In the open position, the bone penetrating pin does not extend beyond the bone contacting surface of the base plate, and in the closed position, the striking element does not extend beyond the working surface. 
     In one embodiment, the fastening element is rotatably attached to the base plate using a hinge pin to connect the striking element to the base plate. The orthopaedic tray trial of the invention may be configured for use as a tibial tray trail for attachment to a resected tibia. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more fully understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a side view of a prior art tibial tray trial fixation system; 
     FIG. 2 is a perspective view of an orthopaedic tray trial of the invention in an open position; 
     FIG. 3 is a perspective view of the orthopaedic tray trial of FIG. 2 in a closed position; 
     FIG. 4 is a side view of the orthopaedic tray trial of FIG. 2 in a closed position; and 
     FIG. 5 is a side view of the orthopaedic tray trial of FIG. 2 in an open position set atop a tibia. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Orthopaedic tray trial  20 , illustrated in FIGS. 2-5, comprises a plate portion  22 , a handle mating portion  24 , and a punch guide opening  26  formed in the tray trial plate  22 . Orthopaedic tray trial  20  is generally shaped for use as a tibial tray trial and includes an generally flat, inferior bone contacting surface  28  and an opposed superior working surface  30 . The mating portion  24  includes holes  32  for receiving bolts of an alignment handle. Tibial tray trial  20  may also include a rim (not shown) around the outer circumference of the plate  22  extending transversely from the working surface  30 . A rim may be useful to seat a trial tibial insert. Alternatively, where a rotating platform knee tibial prosthesis will be employed, tibial tray trail  20  typically does not have a circumferential rim. 
     Tibial tray trial  20  includes two fastening elements  34 . More or fewer fastening elements may be employed consistent with the spirit of the invention depending on the particular use of the orthopaedic tray trial of the invention. Each fastening element  34  includes a striking element  36  having a superior surface  38  and an inferior surface  40 , and a pin  42  extending from the inferior surface  40  in a general direction from the working surface  30  of base plate  22  toward the bone contacting surface  28 . 
     Fastening elements  34  are rotatably connected to base plate  28  by hinge pins  44 . Hinge pins  44  define axes of rotation about which the fastening elements rotate that are coplanar with the base plate  22 . The fastening elements  34  rotate between an open position, shown in FIGS. 2 and 5, wherein the striking element  36  is located above the superior surface  30  and no part of the fastening element  34  extends below the bone contacting surface  28  of the base plate  22 , and a closed position, shown in FIGS. 3-4, wherein pins  42  extend beyond the bone contacting surface  28  of base plate  22  to fix with a bone and no portion of the fastening element  34  extends above the working surface  30  of base plate  22 . 
     Pins  42  may be curved in a plane transverse to the axis of rotation of the fastening elements  34 . This allows pins  42  to enter a bone surface at a perpendicular angle to the surface, and minimizes the amount of bone engaged by pins  42  as they travel into the bone during fixation of the tibial tray trial. 
     Fastening elements  34  and base plate  22  may also have cooperating surfaces  46 ,  48 , respectively (see FIG.  5 ), that are angled so as to stop fastening elements  34  in a closed position wherein the superior surface  38  of the fastening elements is substantially flush with the working surface  30  of the base plate  22 . This configuration prevents a surgeon from over inserting fastening elements  34  into bone. 
     In use, the tibial surface is cut so that the tibial tray trial  20  will rest on a flat surface. Tibial tray trial  20  is then used as a template to select the appropriate size tibial prosthesis for implantation. An alignment handle is used to manipulate the tray trial. Various sizes of tray trials are attached and removed from the alignment handle to select a trial closely matching the tibial plateau. The surgeon may do this with one hand leaving the other hand free. 
     Once the size is selected, the trial is placed to rest on the bone. Holding the handle with one hand, the surgeon can fix the trial to the tibial surface by striking the striking elements  34  with a mallet. Depending on the procedure and the type of tibial prosthesis being implanted, a tibial trial insert (not shown) may be inserted within a rim of tray trial  20 . The insert is used to determine the tibial implant thickness and provide a surface with which a femoral trial, indicative of the implant, will interact. Various trial inserts are tried to select the one of an appropriate thickness. Alignment rods may be used to check the alignment of the tray  20  with the femoral portion of the implant. The surgeon may then remove the alignment handle, replace the patella portion and check the alignment and movement of the trials. Once it has been determined that the trial is appropriately sized and fitted and has been appropriately placed on the tibia, the alignment handle and trial insert are removed. The surgeon will also remove the femoral trial and attach a punch guide to the tray trial. In order to prepare the tibia for the tibial implant, a punch or reaming device is then inserted through a punch guide (not shown) which is placed over the punch guide opening  26 . 
     It will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. All references cited herein are expressly incorporated by reference in their entirety.