Patent Document

FIELD OF DISCLOSURE 
     The disclosed system and method relate implants. More specifically, the disclosed system and method relate to installing an implant for treating hammer toe. 
     BACKGROUND 
     Hammer toe is a deformity of the toe that affects the alignment of the bones adjacent to the proximal interphalangeal (PIP) joint. Hammer toe can cause pain and can lead to difficulty in walking or wearing shoes. A hammer toe can often result in an open sore or wound on the foot. In some instances, surgery may be required to correct the deformity by fusing one or both of the PIP and distal interphalangeal (DIP) joints. Improved implants and surgical devices are desirable. 
     SUMMARY 
     In some embodiments, an implant includes an elongate threaded portion defining a first central longitudinal axis and a groove. The groove defines a second longitudinal central axis that extends in the same direction as the first central longitudinal axis. A blade portion extends from the elongate threaded portion and has a taper terminating at a point. 
     In some embodiments, a method includes forming an incision to gain access to a joint between first and second bones, flexing the first and second bones such that the first and second bones are disposed at an angle with respect to one another, and inserting a surgical device into a first end of the first bone until a trailing end of the surgical device is disposed adjacent to the first end of the first bone. A slot is formed in the first end of the first bone adjacent to a location at which the surgical device is received within the first bone, and a threaded portion of an implant is advanced into a first end of the second bone. The first bone is repositioned such that the slot formed in the first bone aligns with a blade portion of the implant that extends from the first end of the second bone. The first bone is forced into engagement with the blade portion of the implant, and the first surgical device is advanced across the joint and into engagement with a groove defined by the threaded portion of the implant. 
     A method includes inserting a leading end of a surgical device into an exposed first end of a first bone until a trailing end of the surgical device is disposed adjacent to the first end of the first bone. A threaded portion of an implant is advanced into an exposed first end of a second bone, and the first bone is repositioned such that a slot formed in the first bone adjacent to the surgical device aligns with a blade portion of the implant that extends from the first end of the second bone. The first bone is forced into engagement with a blade portion of the implant, and the trailing end of the surgical device is advanced across a joint between the first and second bones and into a groove defined by the threaded portion of the implant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will be more fully disclosed in, or rendered obvious by the following detailed description of preferred embodiments, which are to be considered together with the accompanying drawings wherein like numbers refer to like parts and further wherein: 
         FIG. 1  is an isometric view of one example of an improved hammer toe implant in accordance with some embodiments; 
         FIG. 2  is another isometric view of the hammer toe implant illustrated in  FIG. 1  in accordance with some embodiments; 
         FIG. 3  is a side view of the hammer toe implant illustrated in  FIG. 1  in accordance with some embodiments; 
         FIG. 4  is an end on view of the hammer toe implant illustrated in  FIG. 1  in accordance with some embodiments; 
         FIG. 5  is a sectional view of the hammer toe implant illustrated in  FIG. 1  taken along line  5 - 5  in  FIG. 4  in accordance with some embodiments; 
         FIG. 6  is an isometric view of the hammer toe implant illustrated in  FIG. 1  coupled to a surgical device in accordance with some embodiments; 
         FIG. 7  is an end view of the hammer toe implant illustrated in  FIG. 1  coupled to a surgical device in accordance with some embodiments; 
         FIG. 8  is a cross-sectional view taken along line  8 - 8  in  FIG. 7  of the hammer toe implant illustrated in  FIG. 1  coupled to a surgical device in accordance with some embodiments; 
         FIG. 9  illustrates one example of an incision being made to gain access to a joint between at least two bones in accordance with some embodiments. 
         FIG. 10  illustrates one example of a cutting blade being used to resect faces of adjacent bones of a joint in accordance with some embodiments. 
         FIG. 11  illustrates a surgical device being inserted into a bone adjacent to a broach or drill site in accordance with some embodiments; 
         FIG. 12  illustrates one example of an implant being driven into a bone using a driving tool in accordance with some embodiments. 
         FIG. 13  illustrates an implant in accordance with  FIG. 1  having been inserted into a bone disposed adjacent to the bone in which a surgical device is inserted in accordance with some embodiments; 
         FIG. 14  illustrates the surgical device being advanced into bones and engaging a portion of the implant in accordance with some embodiments; and 
         FIG. 15  illustrates the surgical device being removed from bone and its engagement with the implant in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     This description of preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. The drawing figures are not necessarily to scale and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top,” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral,” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling, and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. 
     The disclosed implant, systems, and methods advantageously enable an implant to be installed through a small incision while stabilizing a joint, such as a metatarsophalangeal joint. Additionally, the implant is capable of being completely disposed within a toe of a patient, which prevents the implant from being caught on bed sheets or other objects like the conventional pins when installed for treating a joint condition. 
       FIGS. 1-8  illustrate one example of an improved implant  100  for treating hammer toe in accordance with some embodiments. As best seen in  FIGS. 1 and 2 , implant  100  includes a threaded portion  102  and a blade portion  104 , which are connected together at an engagement portion  106 . Implant  100  may have a substantially linear geometry, such that a longitudinal axis defined by blade portion  104  is aligned or collinear with a longitudinal axis defined by threaded portion  102 , and have an overall length of approximately 19 mm (approximately 0.75 inches). However, in some embodiments, blade portion  104  is disposed at angle with respect to a longitudinal axis defined by the threaded portion  102  such that a longitudinal axis defined by the blade portion  104  is not aligned nor collinear with a longitudinal axis defined by threaded portion  102 . For example, in some embodiments, the angle is between zero and 45 degrees, and more particularly between approximately five and fifteen degrees. Commonly assigned U.S. patent application Ser. No. 13/086,136, filed Apr. 13, 2011 and which is incorporated by reference herein in its entirety, discloses one example of an implant having an angled (e.g., non-linear) configuration. One of ordinary skill in the art will understand that implant  100  may have other dimensions and be provided in different sizes. For example, implant  100  may be provided in lengths of 16 mm and 22 mm, to identify only a few potential lengths. 
     Threaded portion  102  includes a plurality of threads  108  disposed along its entire length. In some embodiments, the length of threaded portion  102  is approximately 13 mm (approximately 0.5 inches). Threaded portion  102  tapers to a pointed tip  110  to facilitate the advancement of threads  108  into bone. In some embodiments, threads  108  have a maximum outer diameter of approximately 2 mm (approximately 0.08 inches), although one skilled in the art will understand that thread portion  102  may have other dimensions and be configured to be received within a phalanx bone of a person. For example, in some embodiments, threads  108  have an outer diameter of between approximately 1.6 mm and 4 mm, such as, for example, 1.6 mm, 2.4 mm, 3.2 mm, and 4.0 mm, to identify only a few potential possibilities. 
     Threaded portion  102  includes a groove  109  sized and configured to receive a k-wire, pin, or other surgical device or instrument therein as described in greater detail below. Groove  109  extend along the length of threaded portion  102  in a direction that is parallel to a longitudinal length defined by threaded portion  102 . In some embodiments, as best seen in  FIGS. 1 and 2 , a central axis of groove  109  is disposed adjacent to a central longitudinal axis defined by threaded portion  102 . Put another way, the central axis defined by groove  109  is not collinear with, and is parallel to, the central axis defined by threaded portion  102 , which extends through the center of threaded portion  102  and blade portion  104 . In some embodiments, groove  109  is disposed such that it is tangent to a minor diameter of threads  108 . Although not shown, in some embodiments groove  109  is collinear with the central axis defined by threaded portion  102  (and blade portion  104 ).  FIGS. 6 and 7  show a k-wire  10  disposed within groove  109 . In some embodiments, such as the embodiment illustrated in  FIG. 7 , a gap G is provided between k-wire  10  and a side  128  of blade portion  104 , which is disposed opposite of side  130  of blade portion  104  as shown in  FIGS. 4 and 8 . Gap G enables bone to be received between surgical device  10  and blade portion  104 . 
     As best seen in  FIG. 1 , blade portion  104  includes a plurality of serrated edges  112  on first side  114  and on a second side  116 . Serrated edges  112  each have a thickness that is approximately equal to the thickness of blade portion  104 . Put another way, in some embodiments, blade portion  104  does not taper along its thickness direction as best seen in  FIG. 3 . Serrated edges are separated from one another by valleys or indentations  126  shown in  FIGS. 1 and 3 . Blade portion  104  may have a width that is greater than its thickness as best seen in  FIGS. 1 and 2 . For example, blade portion  104  may have a width of approximately 0.4 centimeters (approximately 0.16 inches) and a thickness of approximately 0.1 centimeters (approximately 0.04 inches) each of which taper to point  118  at the distal-most end of blade portion  104 . In some embodiments, blade portion  104  has a substantially rectangular cross-sectional area as illustrated in  FIG. 4 , although one skilled in the art will understand that blade portion  104  may have other cross-sectional geometries. 
     Engagement portion  106  includes a pair of protrusions  120  extending from opposite sides of implant  100  and having rounded outer edges  122  as best seen in  FIGS. 1 and 2 . The sides  124  of protrusions  120  may be substantially parallel with each other as shown in  FIG. 5 . Protrusions extend away from one another in a direction that is perpendicular with respect to a longitudinal direction of implant  100 . 
     A method of installing implant  100  in a joint between at least two bones is described with reference to  FIGS. 9-15 . Although the method is described as installing an implant in the bones of a proximal interphelangeal joint (PIP)  200 , i.e., the joint between proximal phalange  202  and middle phalange  304 , one of ordinary skill in the art will understand that the technique for installing the implant  100  may be applied to other joints, such as, for example, the distal interphelangeal (DIP) joint, i.e., joint  208  between middle phalange  304  and distal phalange  206 . As shown in  FIG. 9 , an incision is made to open the PIP joint  200 . In some embodiments, a cutting tool  300  having a blade  302  is used to resect adjacent faces of proximal phalanx  202  and middle phalanx  204  as shown in  FIG. 10 . The resected surfaces of proximal phalanx  202  and middle phalanx  204  may be debrided as understood by one of ordinary skill in the art. 
     A k-wire, pin, or other suitable surgical device  10  is inserted into the middle phalange  204  and driven through distal phalange  206  and out the end of the toe as shown in  FIG. 11 . In some embodiments, middle phalange  204  is broached or pre-drilled to create an opening  210  also shown in  FIG. 11 , and a pilot hole  212  is formed in proximal phalange  202  using a drill, broach, or other suitable surgical device (not shown). The hole  210  created by the broach is located at a distance from the k-wire  10  that corresponds to the distance of gap G. 
     K-wire  10  is inserted such that trailing end  10 B (not shown in  FIG. 11 ) is disposed within middle phalange  204  or otherwise positioned with respect to joint  200  such that implant  100  can be driven into proximal phalange  202 . In some embodiments, threaded portion  102  of implant  100  is driven into proximal phalange  202  using a driving tool. For example,  FIG. 12  illustrates implant  100  being driven into middle phalange  204  using a driving tool  400 , such as a driving tool disclosed in commonly assigned U.S. patent application Ser. No. 13/086,136, which is incorporated by reference herein in its entirety. One of ordinary skill in the art will understand that other driving tools can be used. Shaft  402  of driving tool  400  can be engaged with a chuck of a drill (not shown) to advance threaded portion  102  of implant  100  into pilot hole  212 . Implant  100  is driven into bone until engagement portion abuts bone. Implant  100  is decoupled from driving tool  400  by axially pulling handle (not shown) away from implant  100  with sufficient force to flex o-ring  404  and separate driving tool  400  from implant  100 . 
       FIG. 13  illustrates threaded portion  102  of implant  100  disposed within a first bone, such as proximal phalange  202 , and end  10 B of surgical device  10  disposed within a second bone, such as middle phalange  204 . Blade portion  104  is exposed as it extends from the distal end of middle phalange  202 . 
     The middle phalange  204  is repositioned such that hole  210  formed by broaching the middle phalange  204  aligns with the blade portion  104  of implant  100 , which extends from the end of proximal phalange  202 . Additionally, k-wire  10  disposed within middle phalange  204  aligns with the groove  109  defined by blade portion  104  of implant  100 , which is disposed within proximal phalange  202 . Middle phalange  204  is pressed into engagement with the blade portion  104  as shown in  FIG. 14 . Serrated edges  112  of blade portion  104  help to maintain the engagement between middle phalanx  204  and blade portion  104  of implant  100 . 
     In some embodiments, k-wire  10  is advanced across joint  200 , into and through middle phalange  202 , and into metatarsal  214  through implant  100  as shown in  FIG. 14 . The k-wire  10  is received within groove  109  such that implant  100  engages surgical device  10 . What was initially leading end  10 A ( FIGS. 11 and 13 ), can be blunted or capped to provide an exposed blunt end  10 C shown in  FIG. 14 . The surgical device  10  can remain within a patient for a period of time, e.g., minutes, hours, days, or months, and then be removed as shown in  FIG. 15  to leave behind implant  100 . 
     Thus, in some embodiments a surgical method includes forming an incision to gain access to a joint between the first bone and the second bone, resecting at least one of the first end of the first bone and the first and of the second bone, and flexing the first bone relative to the second bone to expose the first end of the first bone and the first end of the second bone. A first surgical device is inserted into the first bone until a trailing end of the first surgical device disposed adjacent to a first end of the first bone. The first end of the first bone is broached at a location that is adjacent to a location at which the first surgical device is disposed in the first bone. A pilot hole is formed in the first end of the second bone, and a threaded portion of an implant is advanced into the pilot hole formed in the second bone. The first bone is repositioned such that the hole formed in the first end of the first bone by the broach is aligned with a blade portion of the implant extending from the first end of the second bone. The first bone is forced into engagement with the blade portion of the implant. The first surgical device is advanced across the joint, into the second bone such that first surgical device is received within a groove defined by the threaded portion of the implant. The first surgical device is further advanced across a second joint into a third bone. After a period of time, the first surgical device is removed from its engagement with the implant and the first, second, and third bones while the implant remains disposed within the first and second bones. 
     The implant described above may advantageously be installed through a small incision as described above. Further, the inclusion of a groove in the implant that is sized and configured to receive a k-wire enables the implant to be installed while the joint is stabilized. 
     Although the disclosed implant, system, and method have been described in terms of exemplary embodiments, they are not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the system, implant, and method, which may be made by those skilled in the art without departing from the scope and range of equivalents of the implant, system, and method.

Technology Category: 1