Patent Abstract:
A prosthetic bone implant, the bone implant forming one side of a joint and including a prosthesis and a soft tissue attachment component. The soft tissue attachment component is connected to the bone implant and extends outwardly therefrom and towards a joint line. The soft tissue attachment component is moveable with respect to the prosthesis while connected thereto.

Full Description:
FIELD OF THE INVENTION 
     The present technology relates to surgical procedural devices. The present technology can be used, for example, to attach soft tissue such as tendinous tissue to a bone prosthesis. 
     BACKGROUND OF THE INVENTION 
     Certain surgical procedures require the resection of bone where critical soft tissues, such as tendons, ligaments and muscles, in particular the patella tendon, attach to the bone. It has been difficult to secure attachment of these soft tissues to prosthesis for multiple reasons. 
     First, in natural attachment to bone, there is transition region of soft tissue to bone (i.e., muscle-tendon-bone) that has a gradual change from flexible to rigid. In the reattachment of soft tissue to bone, this transition region is often lost resulting in failure of the soft tissue prosthesis interface from the flexibility of soft tissue to the very rigid metal implant. 
     Second, in certain procedures resection of surrounding soft tissues along with bony resections are required (i.e., resection to obtain adequate surgical margins during the removal of bone cancer such as osteosarcoma). This soft tissue resection often leaves the remaining soft tissues too short to reach their original attachment sites, even if adequate method of attachment directly to metal were available. 
     Currently, several methods are used to create a functional bridge between soft tissue and prosthesis, which exhibit limited success. Where there exists enough length for the soft tissue to reach the prosthesis, the soft tissue is often sutured directly to the prosthesis. Advances have been made in the material and surface treatment of the attachment sites (i.e., the use of porous or foam metals) to improve and promote the in-growth of soft tissue after surgery. However, the relative stiffness of these attachment sites compared to the soft tissue being attached continues to be a problem. 
     When soft tissue length is not adequate to reach the natural attachment site on the prosthesis, a graft is sometimes used to create a bridge. Autograft (via transplant or flap) can help to provide additional functional length of the soft tissue, but does not address the stiffness issue. Also, function of the graft host site is reduced. Allograft is also an option, however, again stiffness is not addressed and known issues of rejection and/or lack of integration with the graft tissue exist. Synthetic materials such as aorta-graft materials have been used to create a sleeve or bridge between the prosthesis and bone. This can address the stiffness issue at the soft tissue attachment site. However, the lack of direct integration of the synthetic material with the prosthesis means that long term loads must be borne by sutures or other suitable materials are used to secure the graft to the prosthesis. As a result, failure of the interface merely moves from the soft tissue/prosthesis interface to the graft/prosthesis interface. 
     In all of the above cases, the preparation and attachment of all of these grafts requires significant time and effort during the surgical setting, which exposes the patient to additional OR time in what can be an already lengthy surgical procedure. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present technology provides a prosthetic bone implant, the bone implant forming one side of a joint and comprising a prosthesis and a soft tissue attachment component connected to the bone implant and extending outwardly therefrom and towards a joint line. The soft tissue attachment component may be moveable with respect to the prosthesis while connected thereto. Furthermore, the soft tissue attachment may extend beyond the joint line and have a first end and a second end, the first end configured to attach to the prosthesis and the second end including a tip, such as, for example, a forked tip configured to engage a soft tissue. 
     In one embodiment, the prosthetic bone implant may further comprise a plurality of filaments attached to the soft tissue attachment component, wherein the filaments are configured to connect the soft tissue attachment component to soft tissue. Alternatively, the soft tissue attachment component may have a first end and a second end, the first end configured to attach to the prosthesis and the second end including a plug configured for attachment to bone. In yet another embodiment, the soft tissue attachment component may have a first end and a second end, the first end configured to attach to the prosthesis and the second end attached to a replacement or resurfacing element for a bony structure. The soft tissue attachment component may be formed integrally with the replacement or resurfacing element. Furthermore, the soft tissue attachment component may have a sufficient length to provide attachment to a piece of soft tissue that has been at least partially resected. 
     The soft tissue attachment may extend from a region of the prosthetic configured to promote ingrowth or on-growth of the soft tissue, such as a porous or foam metal, and hence load share with the soft tissue. The soft tissue attachment mechanism may extend toward or beyond the soft tissues natural attachment site from a region distal to (away from the joint line) the natural attachment site so that when tissue prosthesis integration occurs, it will be at the natural site. 
     In another embodiment, the prosthesis and the soft tissue attachment component may be formed as a one-piece construct. Alternatively, the prosthesis and the soft tissue attachment mechanism may be configured to be connected at the time of surgery. In addition, the soft tissue attachment component may be configured to be modified by a surgeon according to the size and tension needs of a particular procedure. 
     The soft tissue attachment component of the prosthetic bone implant may be composed of a material that is either synthetic or biologic, or a composite of synthetic and biologic materials. Furthermore, the soft tissue attachment component may be composed of a material that is biodegradable or bioresorbable such that over time it is replaced by natural tissue. Still furthermore, the soft tissue attachment component may be at least partially porous. In one embodiment, the soft tissue attachment component may have a variable porosity throughout its length or throughout its cross section, or throughout both its length and its cross section. 
     The soft tissue attachment component of the prosthetic bone implant may be composed at least in part of a material selected from the group consisting of silk mesh or resorbable mesh, Dacron, polytetra fluoroethylene, Texturized or Open-weave poly(ethylene terephthalate), waterswolen poly(2-hydroxyethyl methacrylate), polydioxanone, PDO/Elastin Weave, polyurethane, aromatic porous polyurethane, poly-(L-lactic acid), Polyetheretherketone, allograft or xenograft tendon or ligament, small-intestinal submucosa, collagen, cell seeded collagen matrices, hydrogels, Chitosan, or other known cell scaffold materials. 
     A further aspect of the invention provides a method of securing soft tissue to a prosthetic bone implant. The method may comprise implanting a joint bone prosthesis adjacent to a joint at or near a natural soft tissue attachment site, the prosthesis connected to a one-piece soft tissue attachment component. The method may also include suturing the soft tissue attachment component to the natural soft tissue with filaments. 
     In one embodiment of the method, the step of attaching the soft tissue attachment component to natural soft tissue may include fixing the natural soft tissue between the prongs of a forked end of the soft tissue attachment component. In another embodiment, attaching the soft tissue attachment component to natural soft tissue may include suturing the natural soft tissue to the soft tissue attachment component with filaments connected to the end of the soft tissue attachment component. Other embodiments may include attaching the soft tissue attachment component to a bony structure by implanting a plug into the bony structure, wherein the plug is connected to the soft tissue attachment component, or attaching the soft tissue attachment component to a bony structure by fixing a replacement or resurfacing component to the bony structure, where the replacement or resurfacing component is connected to the soft tissue attachment component. 
     As used herein when referring to bones or other parts of the body, the term “proximal” means close to the heart and the term “distal” means more distant from the heart. The term “inferior” means toward the feet and the term “superior” means toward the head. The term “anterior” means toward the front part or the face and the term “posterior” means toward the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present technology will be better understood on reading the following detailed description of nonlimiting embodiments thereof, and on examining the accompanying drawings, in which: 
         FIG. 1   a  is an isometric view of a prosthetic tibial implant including the soft tissue attachment device of the present invention; 
         FIG. 1   b  is a lateral view of the tibial implant including soft tissue attachment device of the present invention; 
         FIG. 1   c  is an anterior view of the prosthetic tibia shown in  FIGS. 1   a  and  1   b;    
         FIG. 1   d  is a top view of the prosthetic tibial components of  FIGS. 1   a  through  1   c  showing the superior surfaces thereof; 
         FIG. 2   a  is a prosthetic tibia including a modular soft tissue attachment device of the present invention; 
         FIG. 2   b  is a lateral view of the tibia of  FIG. 2   a  showing the soft tissue attachment device spaced anteriorly of the tibia; 
         FIG. 3   a  is an alternate prosthetic component having a receptacle for receiving soft tissue as shown; 
         FIG. 3   b  is an anterior view of the prosthetic component of  FIG. 3   a;    
         FIG. 4   a  is an isometric view of a prosthetic tibial implant having yet an additional alternate embodiment of the soft tissue attachment device of the present invention; 
         FIG. 4   b  is an anterior view of the prosthetic tibial component of  FIG. 4   a;    
         FIG. 4   c  is a lateral view of the prosthetic tibial components of  FIGS. 4   a  and  4   b;    
         FIG. 4   d  is a top view of the prosthetic tibial component of  FIGS. 4   a  through  4   c  joining the superior surface of the component; 
         FIG. 5   a  is an isometric view of yet another alternate soft tissue attachment device of the present invention showing a tibial prosthesis with a proximally extending soft tissue attachment component with resurfacing element; 
         FIG. 5   b  is a posterior view of the prosthetic tibial component of  FIG. 5   a;    
         FIG. 5   c  is a lateral view of the prosthetic tibial component of  FIGS. 5   a  and  5   b;    
         FIG. 5   d  is an anterior view of the soft tissue attachment device of  FIGS. 5   a - 5   c;    
         FIG. 5   e  is a top view of the prosthetic femoral components of  FIGS. 5   a - 5   d;    
         FIG. 6   a  is an isometric view of yet another embodiment of the soft tissue attachment device of the present invention; 
         FIG. 6B  is an isometric view of the embodiment of  FIG. 6A  with the soft tissue attachment element disassembled from the prosthetic tibia; 
         FIG. 7   a  is a front view of an additional embodiment of the present invention; 
         FIG. 7   b  is an isometric view of the ultimate embodiment of  FIG. 7A  with the prosthetic patellar element removed; and 
         FIG. 7   c  is a posterior view of the embodiment of  FIGS. 7   a  and  7   b  with the prosthetic patella disassembled from the soft tissue attachment device. 
     
    
    
     DETAILED DESCRIPTION 
     In describing preferred embodiments of the medical device of the present technology, reference will be made to directional nomenclature used in describing the human body. It is noted that this nomenclature is used only for convenience and that it is not intended to be limiting with respect to the scope or structure of the invention. When referring to specific directions, the device is understood to be described only with respect to its orientation and position during an exemplary application to the human body. 
     Referring to  FIGS. 1   a  through  1   d  there is shown a preferred embodiment of a prosthetic tibial component generally denoted as  10 , which may be part of modular oncology system such as disclosed in U.S. Pat. No. 4,578,081. In such a system large portions of diseased bones are removed and replaced by prosthetic implants such as the proximal tibia. The tibial prosthesis includes a proximal tibial portion  12  and a proximally extending soft tissue attachment device  14 . In the preferred embodiment, soft tissue attachment device  14  includes a stem portion  16 , which is coupled to the proximal end  18  of prosthetic tibia  12 . The device  14  may be one-piece with the proximal tibia such as by being integrally cast therewith or welded thereon. Other techniques such as Selector Laser Melting (SLM) or compression molding may also be used. 
     Soft tissue attachment device  14  includes first and second arms  20  and  22 , which form a generally U-shaped slot  24 . Slot  24  is designed to receive a portion of the patellar tendon. Arms  20  and  22  merge at a junction  26  to form stem  16 . In the preferred embodiment, the proximal superior facing surface of tibial prosthesis  12  is a planar surface  28 . While a U-shaped slot is shown, other shape slots may also be used. 
     In the preferred embodiment, surface  28  includes four proximally extending flange portions  30 ,  32 ,  34 , and  36 . Flange portions  30 ,  32 ,  34 , and  36  are designed to receive a prosthetic bearing surface which, in the preferred embodiment, is made of ultrahigh molecular weight polyethylene (UHMWPE). However, the bearing component may be made of other polymeric or metal materials suitable for prosthetic bearings. When a UHMWPE insert (not shown) is utilized, it may be snapped and locked in recessed grooves  38 ,  40 ,  42 , and  44  formed in flanges  30 ,  32 ,  34 , and  36 , respectively. 
     Referring to  FIGS. 2   a  and  2   b , there is shown a modular connection between the proximally extending tendon attachment device  14  and the proximal portion  18  of tibia prosthesis  12 . The modular attachment includes a flange or plate element  40  having a pair of through holes  42  for receiving screws (not shown), which engage with threaded bores  44  and  46  in tibial prosthesis  12 . Threaded bores  44  and  46  are preferably formed in a recessed area  48  formed in the anterior facing surface of the proximal tibia portion  18 . The recess preferably has a distal surface  50 , which receives a bottom surface  52  of flange portion  40  of the proximally extending stem portion  16  tendon attachment device  14 . Surface  50  provides support for distal surface  52 . As discussed above, stem portion  16  is fixedly attached to or integral with flange portion  40 . The stem portion  16  may be attached by welding so that the tendon attachment device  14  is made one piece with flange portion  40 . 
     Referring to  FIG. 2   b , flange portion  40  includes a proximally facing surface  54 , which engages a distally facing surface  56  on the recessed portion  48  of prosthetic tibial component  12 . Thus flange portion  40 , once assembled, is prevented from proximal-distal movement by surfaces  50  and  56  of recess  48 . 
     Referring to  FIGS. 3   a  and  3   b , there is shown an alternate method of attaching a tendon  60 . In this embodiment the plurality of filaments are woven or stitched into soft tissue similar to suturing. 
     Referring to  FIGS. 4   a  through  4   d , there is shown yet an additional embodiment of the proximally extending tendon attachment device of the present invention. In this embodiment, prosthetic tibia  12  remains essentially unchanged with an alternate tendon attachment device  14   a  having a stem  16   a  attached to an anteriorly facing surface of proximal portion  18  of tibia prosthesis  12 . The tendon attachment area includes four spaced arms  70 ,  72 ,  74 , and  76 , which form U-shaped open areas facing anteriorly and posteriorly as well as medially and laterally. A proximally facing elongate pin  78  is provided. The four spaced arms  70 ,  72 ,  74  and  76  are attached to the soft tissue in the same manner as described with respect to  FIG. 1  after the plug is implanted into the patella for load sharing. Pin  78  can be cylindrical or can have other shapes. 
     Referring to  FIGS. 5   a  through  5   e , there is shown yet an additional design for the proximally extending tendon attachment device wherein, again the tibial prosthetic portion  12  remains the same. However, in this embodiment, a proximally extending tendon attachment device  14   b  includes a stem portion  16   b  attached to the anteriorly facing surface of the tibial prosthesis  12 . A resurfacing portion  80  is provided at the proximal end of the stem  16   b , which the resurfacing portion includes three pointed pins  82 ,  84 , and  86 . Pins  82 ,  84 , and  86  extend anteriorly from an anterior surface  88  of resurfacing portion  80 . The posterior surface of resurfacing element  80  includes a smooth portion  90 , which may be part spherical in shape. Part spherical surface  90  may act as a prosthetic patellar surface once the patella is attached to pins  82 ,  84 , and  86 . In this embodiment, the stem  16   b  and attachment device  14   b  may extend anteriorly and proximally to locate surface  90  of resurfacing portion  80  at the proper location for engaging a trochlear groove of a prosthetic femoral component (not shown). 
     Referring to  FIGS. 6   a  and  6   b  there is shown an alternate embodiment in which a soft tissue attachment element such as a patellar tendon attachment element  200  is coupled to a prosthetic tibial component  212  by clamping element  202 . Attachment element  200  has a curved distal portion  204  which sits in a groove  206  formed in a recess  208  in the anterior portion of component  212 . Portion  204  is clamped within recess  206  by clamp  202 . Clamp  202  includes a pair of apertures  210  for receiving screws (not shown) which thread into threaded bores  214  formed in the anterior surface of component  212  in the area of recess  208 . Soft tissue attachment element  200  includes an anteriorly extending portion  216  which forms a proximal part of curved distal end portion  204 . Portion  216  fits within cut-out  218  of clamp  202  when the soft tissue attachment element  200  is assembled as shown in  FIG. 6A . 
     Referring to  FIGS. 7   a - 7   c , a proximal tibial component  312  with an integral soft tissue attachment element  300  integrally formed therewith such as by welding or casting. Soft tissue attachment element  300  includes a proximal end  302  having a plurality of through holes  304  for receiving the pegged posterior receiving peg elements  306  of a prosthetic patellar component  308 . A small protrusion  310  is formed on the anterior face of proximal end  302  of soft tissue attachment element  300 . Protrusion  310  extends into a recessed bore  312  formed on the posterior face of prosthetic patella  308 . As in all of the other embodiments the proximal surface  328  includes locking elements  314  for fixing a ultra high molecular weight polyethylene bearing surface to the proximal tibia. Such structures are well known in the art. 
     While the soft tissue attachment element is described herein in relation to a tibia similar elements may be used with a femoral knee joint prosthesis component, an elbow prosthesis component or a humeral prosthetic component or any other suitable locations where soft tissue is attached to bone. 
     Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present technology. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology as defined by the appended claims.

Technology Classification (CPC): 0