Abstract:
A method for securing a soft tissue replacement in a bone tunnel includes forming a first and second tunnel in the bone. The second tunnel intersects the first tunnel and defines a first and second access passage. A first flexible member is passed through the tunnel and includes a first end extending out of the first passage, an intermediate portion supporting the soft tissue replacement and a second end extending out of the second passage. The first end of the first flexible member is fastened to an insertion member. A crosspin is positioned between the first passage and the insertion member. The second end of the first flexible member is advanced until a distal portion of the crosspin advances into the first access passage. The insertion member is impacted thereby pushing the crosspin into an engaged position with the bone.

Description:
FIELD OF THE INVENTION 
     The present invention relates to endoscopic soft tissue replacement fixation. More particularly, the present invention relates to an apparatus and a method to reconstruct an anterior cruciate ligament with soft tissue replacements within a femoral tunnel. 
     BACKGROUND OF THE INVENTION 
     The knee joint is frequently the object of injury and is often repaired using arthroscopic surgical procedures. An example of such arthroscopic surgery is the replacement of anterior cruciate ligaments of the knee. The tearing of these ligaments is common in sports activities such as football or skiing. 
     In some prior art procedures, it has been difficult to insert and fasten a soft tissue replacement in a blind bore or tunnel. Attempts have been made to thread the soft tissue replacement through the tunnel and over an anchor, but with some difficulty. Thus far, there is need for improvement in the prior art to develop a quick and efficient method to implant a soft tissue replacement over an implanted anchoring system. 
     Other techniques attempt to use biological fixation to augment or replace mechanical fixation. While increasing fixation strength, these techniques require time to fully realize their fixation potential. Additionally, the techniques may take additional surgical time and resources that a purely mechanical fixation technique may not require. 
     SUMMARY OF THE INVENTION 
     A method for securing a soft tissue replacement in a bone tunnel includes forming a first tunnel in the bone. A second tunnel is formed through the bone and defines a first and second access passage on opposite ends of the second tunnel. The second tunnel intersects the first tunnel. A first flexible member is passed through the tunnel and includes a first end extending out of the first passage, an intermediate portion supporting the soft tissue replacement and a second end extending out of the second passage. 
     The first end of the first flexible member is fastened to an insertion member. A crosspin is positioned between the first passage and the insertion member. The second end of the first flexible member is advanced until a distal portion of the crosspin advances into the first access passage. The insertion member is impacted thereby pushing the crosspin into an engaged position with the bone. 
     A system for securing a soft tissue replacement in a bone tunnel includes a crosspin adapted to be inserted into a femoral tunnel and support the soft tissue replacement. An insertion member includes a distal end adapted to matingly engage a proximal end of the crosspin. The insertion member is adapted to push the crosspin into an engaged position whereby the soft tissue replacement is in a secure relationship with the bone. 
     According to other features, a first flexible member is adapted to be pulled through the femoral tunnel. The first flexible member is adapted to be coupled to the insertion member and pull the insertion member toward the bone thereby locating the crosspin into an engaged position with the femoral tunnel. The system further comprises an impacting tool for imposing a force onto the insertion member in a direction toward the bone. 
     A crosspin for use in soft tissue replacement surgery includes a distal tip portion, an intermediate portion transitioning from the distal portion at a ramp portion, and a longitudinal slot defined by the intermediate portion. The longitudinal slot extends from a first outer longitudinal surface to a terminal longitudinal surface. The terminal longitudinal surface defines a terminal axis, wherein the terminal axis is offset from an axis defining a centerline of a longitudinal axis of the crosspin. 
     A crosspin for use in soft tissue replacement surgery includes a distal portion, an intermediate portion and a proximal portion having a proximal end. The proximal end includes fin portions formed thereon and defines a first outer dimension. The fin portions are adapted to progressively deflect inwardly upon impacting the proximal end in a direction toward the distal portion during insertion of the crosspin into a bone tunnel. The fin portions provide an outward retention force onto a surface of the bone tunnel in an installed position. 
     A crosspin for use in soft tissue replacement surgery includes a distal portion, an intermediate portion, a proximal portion and a breakaway portion. The breakaway portion extends from the proximal portion and is adapted to be disconnected from the proximal portion upon locating the crosspin at a desired depth in the bone tunnel. 
     According to other features, a driver is provided and is adapted to cooperate with the breakaway portion and impose a force onto the breakaway portion causing the breakaway portion to disconnect from the proximal portion. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is an anterior view of a guide wire forming a preliminary tunnel through a portion of the tibia and femur; 
         FIG. 2  is an anterior view of a cannulated drill forming a tunnel in the tibia and femur; 
         FIG. 3  is an anterior view of a guide wire and cannulated drill forming a femoral tunnel; 
         FIG. 4  is an anterior view of the respective tibial and femoral tunnels; 
         FIG. 5  is an anterior view of an insertion instrument cooperating with a flexible member; 
         FIG. 5A  is a perspective view of an insertion instrument according to additional features; 
         FIG. 5B  is a perspective view of an insertion instrument according to additional features; 
         FIG. 5C  is a perspective view of an insertion instrument according to additional features; 
         FIG. 6  is an anterior view of the insertion instrument locating a looped portion of the flexible member into the femoral tunnel; 
         FIG. 7  is an anterior view of a pin inserted into the femoral tunnel to pass through the loop in the flexible member; 
         FIG. 8  is an anterior view of  FIG. 7  shown with the insertion instrument removed and the flexible member looped over and supported by the pin; 
         FIG. 9  is an anterior view of the soft tissue replacement being passed over the pin; 
         FIG. 10  is an anterior view of the soft tissue replacement looped over and supported by the pin; 
         FIG. 11  is an anterior view of a flexible member being drawn through the femoral tunnel by the pin; 
         FIG. 12  is a sectional view of a crosspin and an insertion member used to push a crosspin into a desired location in the femoral tunnel; 
         FIG. 13  is a sectional view of the crosspin shown being driven into the desired area with an impacting instrument to support the soft tissue replacement; 
         FIG. 14  is a perspective view of a crosspin according to additional features; 
         FIG. 15  is a partial sectional view of the crosspin of  FIG. 14  shown driven into a desired location in the femoral tunnel; 
         FIG. 16  is a perspective view of a crosspin according to additional features; 
         FIG. 17  is a sectional view of the crosspin of  FIG. 16  shown being driven into the femoral tunnel with an impacting instrument; 
         FIG. 18  is a sectional view of the crosspin of  FIG. 17  shown inserted into a desired location in the femoral tunnel; 
         FIG. 19  is a perspective view of a crosspin according to additional features shown with a driver; 
         FIG. 20  is a sectional view of the crosspin and driver of  FIG. 19  shown with the crosspin inserted into a desired location in the femoral tunnel; and 
         FIG. 21  is a sectional view of the crosspin and driver of  FIG. 20  shown with a proximal portion of the crosspin disconnected from the body of the crosspin. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Moreover, while the present teachings are discussed in detail below with regard to ACL reconstruction, those skilled in the art will recognize the other types of soft tissue fixation may employ the present teachings. 
     Referring to the drawings, a crosspin  10  ( FIG. 11 ) and a method for implanting the crosspin  10  during ACL reconstruction is shown. With particular reference to  FIGS. 1-4 , a knee  12  generally includes at least a tibia  14  and a femur  18  surrounded by soft tissue  28 . The knee  12  is initially prepared by forming a tibial tunnel  20  and a femoral tunnel  24  which are substantially in line with one another such that a straight and solid object could engage both the tibial tunnel  20  and the femoral tunnel  24  without a substantial amount of stress when the knee  10  is placed in flexion between about 30 and about 110 degrees. It is understood that incisions must first be made in the soft tissue  28  ( FIG. 1 ) surrounding the tibia  14  such that a tool may engage the tibia  14  and the femur  18  to form the tibial tunnel  20  and the femoral tunnel  24 . 
     With specific reference to  FIGS. 1 and 2 , a device such as a guide wire or K-wire  30  is used to produce a preliminary tunnel passing through a portion of the tibia  14  and a portion of the femur  18  when the knee is flexed. A blind femoral tunnel  34  is then formed in the femur  18  with a cannulated drill/reamer  36  guided along the guide wire  30  to enlarge the tunnel  20 . The blind femoral tunnel  34  terminates below the surface of the femur  18  and includes an entrance but no discernable exit. It is appreciated that the femoral tunnel  34  may alternatively form an exit through the femur  18 . 
     Turning to  FIGS. 3 and 4 , the femoral tunnel  24  is formed by forming a preliminary tunnel with a guide wire  38 . Next, a cannulated drill/reamer  40  is guided along the guide wire  38  to form the femoral tunnel  24  defining a first and second access passage  44  and  46 , respectively. The respective femoral tunnels  20  and  24  intersect at an intersection area  48  ( FIG. 4 ). While the femoral tunnel  24  is shown having a consistent outer diameter from the first and second access passages  44  and  46 , it is appreciated that the femoral tunnel  24  may alternatively be reamed to a predetermined location between the intersection area  48  and the second access passage  46  or a distance sufficient to accept the crosspin  10  into a desired position. 
     Those skilled in the art will appreciate that any suitable tool may produce the respective tunnels such as a pneumatic or electric drill or reamer. Furthermore, the diameter of the tibial tunnel  20  and the femoral tunnel  24  depends upon the size of the soft tissue replacement (described further herein) to be implanted into the patient. The larger the replacement needed, the larger the diameter of the tibial tunnel  20  and the femoral tunnel  24 . The tibial tunnel  20  and the femoral tunnel  24  may be of any required diameter, but are generally between about 5 and about 18 millimeters. It is appreciated, however, should a larger diameter replacement be necessary, a larger diameter may be produced in the tibia  14  and the femur  18  to receive the implant. Likewise, smaller tunnels may be formed if a smaller implant is necessary. 
     With further reference to  FIGS. 5-8 , the method of implanting the crosspin  10  will be further described. Once the respective tibial and femoral tunnels  20  and  24  are formed, a flexible member  50  is introduced into the tibial tunnel. The flexible member  50  may be any generally known flexible member suitable for the purpose such as a mono- or poly-filament suture, a flexible wire, or cord made of any suitable material. The flexible member  50  is positioned at the intersection area  48  with an insertion instrument or fork  54 . Specifically, the fork  54  includes a shaft portion  56  and a pair of cannulated finger portions  58  and  60 . The flexible member  50  is across the respective finger portions  58  and  60  of the cannulated fork  54  such that opposite ends  62  and  64  of the flexible member  50  extend adjacent to proximal end  68  of the fork  54 . A loop portion  70  is formed at an intermediate portion  72  of the flexible member  50  and extends between the respective fingers  58  and  60 . 
     With reference to  FIG. 5A , an insertion instrument  54 ′ according to additional features is shown. The insertion instrument  54 ′ includes a pair of fingers  58 ′ and  60 ′. A transverse passage  59 ′ accommodates a flexible member  50  therethrough. With reference to  FIG. 5B , an insertion instrument  54 ″ according to additional features is shown. The insertion instrument  54 ″ includes a dual tube configuration having a passage  59 ″ defined at a distal end for accommodating a flexible member  50 . With reference to  FIG. 5C , an insertion instrument  54 ′″ according to additional features is shown. The insertion instrument  54 ′″ includes a single tube configuration having a passage  59 ′″ defined at a distal end for accommodating a flexible member  50 . Those skilled in the art will appreciate that an intermediate portion  72  of the flexible member  50  may be inserted at the intersection area  48  by other methods and with other devices. 
     Once the looped portion  70  is presented at the intersection area  48 , a guide wire or pin  76  is inserted into the femoral tunnel  24  at the first access passage  44 . The pin  76  passes through the loop portion  70  of the flexible member  50  and is passed until a distal end  80  ( FIG. 7 ) extends through the second access passage  46  ( FIG. 8 ). Next, the insertion instrument  54  may be removed from the tibial tunnel  20 . Movement of the insertion instrument  54  downward (as viewed in  FIG. 7 ) allows the flexible member  50 , supported by the pin  76 , to maintain the intermediate portion  72  at a location passing over and supported by the pin  76 . The opposite ends  62  and  64  of the flexible member  50  extend out of the tibial tunnel  20 . It is appreciated that while the pin  76  is described herein as a distinct component from the drill bit  38  used to form the femoral tunnel  24 , the drill bit  38  may likewise be employed to support the flexible member  50 . 
     With particular reference to  FIGS. 9 and 10  the positioning of a soft tissue replacement  86  will be described. The soft tissue replacement  86  is affixed to the first end  62  of the flexible member  50 . The first end  62  of the flexible member  50  will hereinafter be referred to as the trailing end and the second end  64  of the flexible member  50  will hereinafter be referred to as the leading end for illustrative purposes. It is appreciated that the second end  64  of the flexible member  50  may alternatively be affixed to the soft tissue replacement  86  and therefore identified as the trailing end. 
     The soft tissue replacement  86  may be any suitable replacement such as a hamstring portion, an allograft tissue replacement, a xenograft tissue replacement or an artificial soft tissue replacement which may be produced from materials such as polymers or metal. After the soft tissue replacement  86  has been affixed to the trailing end  62 , the leading end  64  of the flexible member  50  is pulled thereby drawing the soft tissue replacement  86  first through the tibial tunnel  20  and then through the femoral tunnel  24  over the pin  76  and back down the blind tunnel  34  and out through the tibial tunnel  20 . This action produces a loop  90  of the soft tissue replacement  86  over the pin  76  inside of the femoral tunnel  24 . After being looped over the pin  76 , two free ends  92  and  94  of the soft tissue replacement  86  extend from the tibial tunnel  20  adjacent to the tibia  14  ( FIG. 10 ). 
     Turning now to  FIGS. 11-13 , once the soft tissue replacement  86  has been looped over the pin  76 , the crosspin  10  is located into the femoral tunnel  24 . First, a second flexible member  100  is drawn through the femoral tunnel  24  and under the soft tissue replacement  86 . The second flexible member  100  is coupled to an eyelet  104  on the pin  76  and pulled through the tunnel  24  from the first access passage  44  and out the second access passage  42 . It is appreciated that if the drill bit  38  was utilized to support the soft tissue replacement  86 , an eyelet incorporated on a proximal end of the drill bit  38  may utilized to couple the second flexible member  100  thereat, and thereafter, draw the flexible member  100  through the tunnel  24 . 
     Once the flexible member  100  extends out of the first access passage  44 , it is passed through a cannulated portion  108  formed through the crosspin  10 . Next, the flexible member  100  is coupled to an insertion member  110  proximate to a proximal end  114  of the crosspin  10 . A distal end  118  of the crosspin  10  is then aligned at the first access passage  44  and the flexible member  100  is subsequently pulled from the second access passage  46  in a direction leftward as viewed from  FIG. 12 . This action allows the distal end  118  of the crosspin  10  to ingress into the tunnel  24  while locating the insertion member  110  into a nested, engaged position with the proximal end  114  of the crosspin  10  ( FIG. 13 ). 
     The proximal end  114  of the crosspin  10  generally defines a square cross section. An intermediate portion  132  generally defines a circular cross section for mating with the wall of the femoral tunnel  24 . The distal end  118  defines a circular stepped down extension from the intermediate portion  132 . It is appreciated that the proximal end  114  and a proximal surface  120  of the crosspin  10  are configured to facilitate a mating engagement with an engagement end  124  of the insertion member  110 . 
     With reference to  FIG. 13 , an impacting instrument  130  is used to impact an impacting surface  138  of the insertion member  110  in a direction toward the crosspin  10 . Subsequent impacting causes the crosspin  10  to be pushed into the tunnel  24  until a desired location is achieved. During translation of the crosspin  10  from the first access passage  44  toward the second access passage  46 , the soft tissue replacement  86  transitions from a looped relationship at the outer diameter of the distal portion  118  of the crosspin  10  to a looped relationship at the intermediate portion  132  of the crosspin  10 . The insertion member  110  includes a neck portion  140  adapted to be received a predetermined distance into the femoral tunnel  24  at the first access passage  44 . The insertion member  110  is subsequently disconnected from the flexible member  100 . The crosspin  10  is comprised of a bioabsorbable material or any suitable biocompatible material. 
     With reference to  FIGS. 14 and 15  a crosspin  210  according to other features is shown. The crosspin  210  includes a distal tip portion  212 , an intermediate portion  216  and a proximal portion  218 . A ramped transition portion  220  leads from the distal tip portion  212  to the intermediate portion  216 . The ramped transition portion  220 , intermediate portion  216  and the proximal portion  218  define a groove or longitudinal slot  224 . The slot  224  is adapted to accept the flexible member  100  therethrough. The slot  224  is arranged from a first longitudinal surface  228  of the crosspin  210  to a terminal location  230  beyond a centerline  232  of the crosspin. In this way, the slot  224  of the crosspin  210  is offset from the centerline  232 . 
     The distal tip portion  212  of the crosspin  210  extends from a second longitudinal surface  238  to the ramped portion  220  at the terminal location  230  of the slot  224 . In this regard, the distal tip portion  212  presents a low profile approach to negotiate under the looped portion  90  of the soft tissue replacement  86 . As the crosspin  210  is pushed into the tunnel  24  with the insertion member  110  according to the teachings above, the soft tissue replacement  86  is initially passed under by the distal tip portion  212 , urged up the ramped portion  220  and finally communicated along the first longitudinal surface  228  until the desired location is achieved ( FIG. 15 ). 
     Turning now to  FIGS. 16-18  a crosspin  310  according to other features will be described. The crosspin  310  generally includes a distal tip portion  312 , an intermediate portion  316  and a proximal portion  318  having a proximal end  330 . The proximal portion  318  includes a plurality of fin portions  334  formed thereon defining an outer dimension  340 . The fin portions  334  are adapted to progressively deflect inwardly ( FIG. 17 ) as the crosspin  310  ingresses into the femoral tunnel  24  upon impacting the proximal end  330  with an impacting tool  342 . As the fin portions  334  ingress into the femoral tunnel, they provide a radial outward force into the wall of the femoral tunnel  24  thereby improving retention of the crosspin  10  in the femoral tunnel  24 . 
     The impacting tool  342 , such as a mallet, is adapted to impact the proximal end in a direction toward the distal portion  312  during insertion of the crosspin  310  into the femoral tunnel  24  to a desired location ( FIG. 18 ). The fin portions  334  are tapered outwardly from the intermediate portion  316  to the proximal end  330 . The fin portions  334  include arcuate outer surfaces  348  for cooperating with the outer wall of the femoral tunnel  24 . In this way, the outer dimension  340  of the fins  334  define a conical surface. The outer surfaces  348  are threaded for facilitating removal of the crosspin  310 . 
     The fin portions  334  of the crosspin  310  are comprised of a flexible material suitable to facilitate inward radial direction upon impacting the proximal surface  330 . A suitable flexible material includes, but is not limited to, Lactosorb available from Biomet, Inc., of Warsaw Indiana or titanium for example. It is appreciated that the crosspin  310  may be formed with the flexible material as a unitary component. Alternatively, the fin portions  334  may be formed separately of flexible material and subsequently, or concurrently, mated with the intermediate portion  316  of the crosspin  310  having an alternate material. The crosspin  310  may be inserted into the femoral tunnel  24  in accordance with the teachings set forth above, or may be used in cooperation with other techniques for locating a soft tissue replacement  86  over the surface of the crosspin  310  in a femoral tunnel  24 . 
     With reference now to  FIGS. 19-21  a crosspin and system for inserting the crosspin  410  according to other features will be described. The crosspin  410  generally includes a distal tip portion  412 , an intermediate portion  416 , a proximal portion  418  and a breakaway portion  419  having a breakaway end  420 . As will be described, the breakaway portion  419  is adapted to be disconnected from the proximal portion  418  upon locating the crosspin  410  at a desired depth into the femoral tunnel  24 . 
     The crosspin  410  transitions from the proximal portion  418  to the breakaway portion  419  at an intersection area  426 . As will be described, the breakaway portion  419  is disconnected from the proximal portion  418  at the intersection area  426 . The breakaway portion  419  tapers inwardly from an engagement surface  430  toward the intersection area  426 . The engagement surface  430  is adapted to be matingly received by a driver  440 . 
     The driver  440  generally includes a first engaging wall  442 , a second engaging wall  444 , a third engaging wall  446  and a fourth engaging wall defined by a slidable cover portion  448 . The breakaway portion  419  of the crosspin  410  is adapted to be inserted into the driver  440  through an access passage  450 . The cover portion  448  is subsequently closed over the breakaway portion  419  of the crosspin  410  thereby capturing the breakaway portion  419  in the driver  440 . It is appreciated that the cover portion  448  may alternatively be a stationary wall whereby the breakaway portion  419  of the crosspin  410  may be inserted axially into an opening defined opposite an end wall  456 . The driver  440  is adapted to impose rotational movement onto the breakaway portion  419  if desired during insertion of the crosspin  410  into the tunnel  24 . Accordingly, the engagement surface  430  defines a hexagonal surface for mating with the engagement walls  442 - 448  of the driver  440 . It is appreciated however, that other complementary engagement surfaces may be employed on the proximal portion  418  and the driver  440 . Furthermore, it is appreciated that a conventional nut driver may similarly be employed. 
     Once the driver  440  locates the crosspin  410  at a desired location in the femoral tunnel  24  ( FIG. 20 ), the breakaway portion  419  is ready to be disconnected from the crosspin  410 . The crosspin  410  is formed as a unitary piece by any suitable biocompatible material. In this regard, a force is imposed onto the driver  440  causing the breakaway portion  419  of the crosspin  410  to fracture or shear from the intermediate portion  416  ( FIG. 21 ). It is appreciated that the breakaway portion  419  may alternatively be formed as a separate component and joined to the proximal portion  418  of the crosspin  410  by any suitable mechanical or chemical fastening techniques. The disconnecting force imposed by the driver  440  in that regard must be adequate to overcome the mechanical or chemical fastening to disconnect the breakaway portion  419  of the crosspin  410  from the proximal portion  418 . It is also appreciated that while the breakaway portion  419  of the crosspin  410  is described as cooperating with the driver  440 , the crosspin  410  alternatively may be urged into the femoral tunnel  24  by the insertion member  110  ( FIG. 12 ) according to the teachings above and subsequently sheared from the proximal portion  418  by an impact force such as imparted by the impacting instrument  130  ( FIG. 13 ). Furthermore, the crosspin  410  may be located into the femoral tunnel  24  by any suitable method and the breakaway portion  419  be disconnected by any method such as with the impacting instrument  130 . 
     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification and the following claims.