Abstract:
A cutting implement includes a first tubular portion and a second tubular portion. Each tubular portion is hollow and includes a blade element at a distal end. The blade element helps define an aperture that allows access to the interior hollow portion of the tubular portion. A ligament graft element is threaded through the aperture of each tubular portion and the respective tubular portions are interoperated to cut the ligament graft.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 13/832,638, filed Mar. 15, 2013, issued as U.S. Pat. No. 8,894,676, which is a continuation-in-part of co-pending U.S. Ser. No. 13/493,320, filed Jun. 11, 2012, issued as U.S. Pat. No. 8,894,675. Each of the identified applications is incorporated by reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to a cutting instrument adapted to help a surgeon harvest a replacement tendon for an anterior cruciate ligament (ACL) injury from the quadriceps tendon. 
     BACKGROUND 
     Most people can go through the majority of their life without ever appreciating the complicated structure of the knee that helps them walk. However, the knee remains a fragile mechanical structure that is readily susceptible to damage. While medical advances have made repairing the knee possible, repair of certain types of injuries results in other long term effects. To assist the reader,  FIG. 1  is provided with a brief explanation of the components of the knee. 
     For the purposes of the present disclosure, and as illustrated, the knee may be composed of the quadriceps muscles  10 , the femur  12 , the articular cartilage  14 , the lateral condyle  16 , the posterior cruciate ligament  18 , the anterior cruciate ligament  20 , the lateral collateral ligament  22 , the fibula  24 , the tibia  26 , the patellar tendon  28 , the meniscus  30 , the medial collateral ligament  32 , the patella  34  (shown slightly displaced to the side—it normally rests in the center of the knee) and the quadriceps tendon  36 . Of particular interest for the purposes of the present disclosure is the anterior cruciate ligament (ACL)  20  and what is done to repair the ACL  20 . 
     ACL tears are common in athletes and are usually season ending injuries. The ACL  20  cannot heal—it must be surgically reconstructed. The reconstruction requires replacement tissue. The most common tissue used is a central slip of the patient&#39;s own patellar tendon  28 . In practice, the patellar tendon  28  has proven to be generally effective, but the size of the graft that can be used is limited to the size of the patient&#39;s own patellar tendon  28 . As a rule of thumb, only a third of the patellar tendon  28  may be harvested as a graft. Thus, a doctor will measure the width of the patellar tendon  28 , divide by three, and take the middle third of the patellar tendon  28 . Such harvested grafts are rarely more than 10 mm wide and may be smaller. Taking this tissue from a person&#39;s patellar tendon  28  also causes significant pain and discomfort in the post operative healing period, which may last up to a year, and up to twenty (20) percent of these patients are left with chronic anterior knee pain. 
     Some doctors recommend and use other graft sources, such as cadaver grafts, but cadaver grafts have a higher failure rate. Additionally, there is a non-zero chance of disease transmission or rejection by the patient&#39;s immune system. As a final drawback, cadaver grafts are usually quite expensive and may not be covered by some insurance companies. 
     Other doctors use hamstring tendons (e.g., the distal semitendinosus tendon) because the scar created during harvesting is relatively small and there is less pain during the rehabilitation, but again, the hamstring tendon has its own collection of disadvantages. The disadvantages include the fact that once the graft is taken, a patient&#39;s hamstring will never recover to its previous strength. Further, all hamstring reconstructions stretch and are looser than the original ACL  20 . This loosening is particularly problematic in younger female athletes. 
     Another alternative graft source is the quadriceps tendon  36 . The quadriceps tendon  36  is larger and stronger than either the patellar tendon  28  or the hamstring tendon. The quadriceps tendon  36  is likewise stiffer and less prone to stretching or plastic deformation. However, the qualities that make the quadriceps tendon  36  attractive also contribute to the difficulty in harvesting a graft from the quadriceps tendon  36 . Existing surgical implements require a large incision up the longitudinal axis of the femur  12  on the front or ventral/anterior side of the thigh to cut down to the level of the quadriceps tendon  36 , resulting in a large post operative scar. Additionally, the quadriceps tendon  36  has a consistency similar to the proverbial shoe leather, making it difficult to cut. However, an ACL  20  repaired with grafts from the quadriceps tendon  36  generally results in almost no anterior knee pain postoperatively over the short or long term and recovers quicker. 
     The present inventor&#39;s prior application, U.S. patent application Ser. No. 13/102,562 (&#39;562 application), filed May 6, 2011 (which is hereby incorporated by reference in its entirety), provides a number of devices designed to create a graft from the quadriceps tendon  36  and discloses an element to make the initial cut on the quadriceps tendon  36  as well as a number of secondary cutting implements to trim the distal end of the graft. While these secondary cutting implements are adequate to perform their intended purpose, alternate devices may be more cost effective or have easier engineering realities. The previously incorporated &#39;320 application also provides suitable secondary cutting implements, but again, alternate devices may be more cost effective, be more efficacious at cutting, or have easier engineering realities. 
     SUMMARY 
     The present disclosure provides a secondary cutting implement that is adapted to trim a distal end of a preliminarily harvested graft from the quadriceps tendon in a minimally invasive manner. Once the quadriceps tendon graft is secured, it may be used in conventional manners to repair the anterior cruciate ligament (ACL). 
     The secondary cutting implement comprises a first hollow tubular element and a second hollow tubular element that telescopingly fits within the first tubular element. The distal ends of each tubular element include an interior blade element positioned perpendicular to a longitudinal axis of the tubular element. The interior blade elements are sized such that the distal end of each tubular portion is at least partially open. That is, the blade elements help define an aperture at the distal end of the tubular hollow elements. 
     In use, the quadriceps tendon is cut to a desired length and then the graft portion is threaded through the open distal end of the first tubular element. The graft portion is also threaded through the open distal end of the second tubular element. The tubular elements are rotated in opposite directions causing the interior blade elements to trim the distal end of the graft. 
     An additional embodiment differs in that only a single one of the tubular elements has a blade. Likewise, the distal ends of the tubular elements include a cutaway or notch that facilitates insertion of the bone plug portion of the graft as the graft is threaded through the open distal end. Additionally, a third tubular element may be included that upon insertion closes the cutaway or notches in the first and second tubular elements to improve cutting when the notches are partially aligned. 
     While the present disclosure focuses on the use of the tubular cutting implement in the context of cutting quadriceps tendons for repairing ACL injuries, the present disclosure is not so limited, and the tubular cutting implement may be used in other sorts of procedures. 
     Those skilled in the art will appreciate the scope of the disclosure and realize additional aspects thereof after reading the following detailed description in association with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure. 
         FIG. 1  illustrates a conventional knee; 
         FIG. 2  illustrates an exploded perspective view of an exemplary embodiment of the secondary cutting implement of the present disclosure; 
         FIGS. 3A-3F  schematically illustrate operation of the secondary cutting element; 
         FIG. 4  illustrates a flow chart describing the operation of the secondary cutting element; 
         FIG. 5  illustrates an exploded perspective view of an exemplary embodiment of the secondary cutting implement of the present disclosure; 
         FIG. 6  illustrates a side view of the secondary cutting implement of  FIG. 5 ; 
         FIG. 7  illustrates a perspective close up of the cutting end of the secondary cutting implement of  FIG. 5 ; 
         FIG. 8  illustrates a side close up of the cutting end of the cutting implement of  FIG. 5 ; and 
         FIG. 9  illustrates a top close up of the cutting end of the cutting implement of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the disclosure and illustrate the best mode of practicing the disclosure. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
       FIG. 2  illustrates a first exemplary embodiment of a secondary cutting implement  50  according to the present disclosure. The secondary cutting implement  50  is useful for trimming a graft (e.g. graft  80  explained below) being harvested from the quadriceps tendon  36 , such as occurs when the cutting implement of the previously incorporated &#39;562 application is used to cut a graft from the quadriceps tendon  36 . The secondary cutting implement  50  has a first element  52 , which is hollow and has a first handle end  55  and a first distal end  56 . The first distal end  56  includes a first blade element  58 . The first blade element  58  is positioned perpendicular to a longitudinal axis  60  of the first element  52 . The first blade element  58  may be integrally formed with the body of the first element  52  or fixedly secured thereto. In an exemplary embodiment, the first element  52  is adapted to be reusable while the first blade element  58  is removably affixed thereto such that it can be replaced readily. Thus, the first blade element  58  may be considered disposable or reusable as desired. The first blade element  58  extends, in an exemplary embodiment, approximately halfway across first distal end  56  (e.g., covering approximately 45-55% (and in an exemplary embodiment approximately 51%) of the area of the first distal end  56 ) and partially defines a first aperture  62  through which a graft may be threaded as explained in greater detail below. In an exemplary embodiment, the first element  52  is made from a metal such as surgical stainless steel (e.g., made out of chromium, nickel, molybdenum, and/or titanium) such as 316L, 316LVM and/or compliant with ASTM F138. In an alternate embodiment, the first element  52  is made from a polymer based material. The first blade element  58  may be made from surgical steel, glass, obsidian, diamond, or the like as desired. In an exemplary embodiment, the first element  52  may be approximately 100 mm long. 
     The second element  54 , which is hollow and has a second handle end  64  and a second distal end  66 . The second distal end  66  includes a second blade element  68 . The second blade element  68  is positioned perpendicular to a longitudinal axis  70  of the second element  54 . The second blade element  68  may be integrally formed with the body of the second element  54  or fixedly secured thereto. In an exemplary embodiment, the second element  54  is adapted to be reusable while the second blade element  68  is removably affixed thereto such that it can be replaced readily. Thus, the second blade element  68  may be considered disposable or reusable as desired. The second blade element  68  extends, in an exemplary embodiment, approximately halfway across second distal end  66  (e.g., covering approximately 45-55% (and in an exemplary embodiment approximately 51%) of the area of the second distal end  66 ) and at least partially defines a second aperture  72  through which a graft may be threaded as explained in greater detail below. In an exemplary embodiment, the second element  54  is made from a metal such as surgical stainless steel (e.g., made out of chromium, nickel, molybdenum, and/or titanium) such as 316L, 316LVM and/or compliant with ASTM F138. In an alternate embodiment, the second element  54  is made from a polymer based material. The second blade element  68  may be made from surgical steel, glass, obsidian, diamond, or the like as desired. In an exemplary embodiment, the second element  54  may be approximately 120 mm long and 23 mm in interior diameter. The first element  52  may be sized such that its interior diameter is just large enough to fit around the exterior diameter of second element  54 . 
     By design, the first element  52  is shorter than the second element  54 , and the second element  54  telescopingly fits within the first element  52  such that the second handle end  64  extends out past the first handle end  55  so as to facilitate manipulation of the second element  54  within the first element  52 . 
     In an exemplary embodiment, the handle ends  55  and  64  may be abraded, knurled, or otherwise textured to provide a firm gripping surface. In an alternate embodiment, there may be an explicit handle attached to or formed on the handle ends  55  and  64  to make manipulation and grip more natural. 
       FIGS. 3A-3F  illustrate a technique of using the secondary cutting implement  50  as further explained in the flowchart of  FIG. 4 . The process  100  of harvesting the graft  80  begins with the incision being made (block  102 ) and the tendon being cut to form the graft  80  (block  104 ). As explained in the previously incorporated &#39;562 application, the graft  80  may be created from the quadriceps tendon  36 , and may include a terminal bone plug formed from the patella. 
     Once the graft  80  is cut from the quadriceps tendon  36 , the cutting implement is removed and the first element  52  is threaded through the first aperture  62  (block  106 ), through the hollow portion of the first element  52  and out the first handle end  55 . Thus, the interior dimensions of the hollow portion of the first element  52  should be sized so as to accommodate the graft  80  and the bit of patella  82  Likewise, the size of the first aperture  62  should be sufficient to pass both the graft  80  and the bit of patella  82 . 
     Note that as used herein “threaded through” or similar phrases draws analogy to threading a needle, and does not refer to the threads on a screw. 
     The graft  80  may then be threaded through the second aperture  72  and the second element  54  (block  108  and  FIG. 3C ). Note that if the apertures  62  and  72  are aligned and the second element  54  is already positioned within the first element  52 , the graft  80  may be threaded through the first and second elements  52 ,  54  concurrently. As is seen in  FIG. 3C , the second handle end  64  extends past the first handle end  55 . Likewise, at least initially, the apertures  62  and  72  are aligned to allow the graft  80  to pass therethrough. 
     The second element  54  is then rotated relative to the first element  52  (block  110 ,  FIGS. 3D &amp; 3E ). As the two elements  52  and  54  are rotated relative to one another, the blade elements  58  and  68  rotate to one another and effectively close the aperture through which the graft  80  has been passed. This allows the blade elements  58  and  68  to scissor together, thereby cutting the graft  80 . Once the rotation has been effectuated sufficiently, the graft  80  is severed (block  112 ). 
     The graft  80  is then removed (block  114 ) as well as the cutting implement  50  (block  116 ,  FIG. 3F ). Then the graft  80  may be used to repair the ACL as desired. 
     In an alternate embodiment, the second cutting element may be eliminated. In this regard, an exemplary embodiment of a secondary cutting implement  150  is illustrated in a perspective exploded format in  FIG. 5 . The secondary cutting implement  150  has a first element  152 , which is hollow and has a first handle end  154  and a first distal end  156 . The first handle end  154  may be encapsulated in a resilient polymeric annulus  155  which may be textured or knurled to provide a secure grip. The first distal end  156  includes a blade element  158 . The blade element  158  is positioned perpendicular to a longitudinal axis  160  of the first element  152 . The blade element  158  may be integrally formed with the body of the first element  152  or fixedly secured thereto. In an exemplary embodiment, the first element  152  is adapted to be reusable while the blade element  158  is removably affixed thereto such that it can be replaced readily. Thus, the blade element  158  may be considered disposable or reusable as desired. The blade element  158  extends, in an exemplary embodiment, approximately halfway across first distal end  156  (e.g., covering approximately 45-55% (and in an exemplary embodiment approximately 51%) of the area of the first distal end  156 ) and partially defines a first aperture  162  through which a bone plug portion of a graft  80  may be threaded as explained above. The first distal end  156  further includes a cut out portion which further defines the first aperture  162 . In an exemplary embodiment, the cut out portion is an L-shaped section removed from the cylinder of the body of the first element  152 . The cut out section may be approximately 25 mm long and remove about 30-50% (and in an exemplary embodiment 49%) of the circumference of the first distal end  156 . The cutout portion provides more room for the first aperture  162  to accommodate the bone plug. 
     In an exemplary embodiment, the first element  152  is made from a metal such as surgical stainless steel (e.g., made out of chromium, nickel, molybdenum, and/or titanium) such as 316L, 316LVM, and/or compliant with ASTM F138. In an alternate embodiment, first element  152  is made from a polymer based material. The blade element  158  may be made from surgical steel, glass, obsidian, diamond, or the like as desired. In an exemplary embodiment, the first element  152  may be approximately 200 mm long. 
     The secondary cutting implement  150  further includes a second element  164 , which is hollow and has a second handle end  166  and a second distal end  168 . Instead of a cutting element, the second element  164  has a blunt edge  172 . The blunt edge  172  is positioned perpendicular to a longitudinal axis  174  of the second element  164 . The blunt edge  172  may be formed from the same material as the body of the second element  164  or may be removably affixed to the body. The blunt edge  172  extends, in an exemplary embodiment, approximately half way across second distal end  168  (e.g., covering approximately 45-55% (and in an exemplary embodiment approximately 51%) of the area of the second distal end  168 ) and at least partially defines a second aperture  170 . The second distal end  168  further includes a cut out section, which, in an exemplary embodiment is L-shaped and helps define the second aperture  170 . The cut out section facilitates threading the bone plug portion of the graft  80  through the hollow portion of the second element  164 . The cut out section may be approximately 25 mm long 
     In an exemplary embodiment, the second element  164  is made from a metal such as surgical stainless steel (e.g., made out of chromium, nickel, molybdenum, and/or titanium) such as 316L, 316LVM, and/or compliant with ASTM F138. In an alternate embodiment, second element  164  is made from a polymer based material. In an exemplary embodiment, the second element  164  may be approximately 460 mm long. By design, the second element  164  has a smaller radius than the first element  152  such that the second element  164  may telescopingly fit within the first element  152 . Likewise, by design the first element  152  is shorter than the second element  164  such that that the second handle end  166  extends out past the first handle end  154  so as to facilitate manipulation of the second element  164  within the first element  152 . 
     In addition to first element  152  and second element  164 , the secondary cutting implement  150  may further (but optionally) include a third element  176  which is provided to lend stability to the secondary cutting implement  150 . In particular, the third element  176  may be included such that on insertion, the third element  176  closes the cutaway or notches in the first element  152  and the second element  164 , so as to improve cutting when the notches are partially aligned. That is, with the cut outs on the first and second elements  152 ,  164 , there is a point in the counter-rotation of the elements  152 ,  164  where the graft  80  is not supported, which makes cutting the tendon difficult. Thus, the third element  176  may be telescopingly inserted between the first element  152  and the second element  164  and provide support for the tendon during cutting. The third element  176  includes a third handle end  178  and a third distal end  180 . The third handle end  178  includes a flange  182  that prevents over-insertion of the third element  176  into the first element  152  and provides a method of maintaining forward pressure on the first element  152  to improve its effectiveness. In an exemplary embodiment, the third element may be approximately 280 mm long. 
       FIG. 6  illustrates the secondary cutting implement  150  assembled. The distal ends  156 ,  168  and  180  are all proximate one another as the elements  152 ,  164 ,  176  telescopingly fit within one another (second inside third inside first). The cut outs on the first and second elements  152 ,  164  line up and allow the bone plug to pass through readily. Additionally, the user may grasp the resilient polymeric annulus  155  and the handle end  166  to rotate the first and second elements  152 ,  164  relative to one another so as to cause the blade element  158  to engage and sever the tendon. The flange  182  may be used to slide the third element  176  back and forth as needed (i.e., it may be retracted during insertion of the bone plug and tendon and then slid forward once the threading is done and the operator is ready to begin cutting). 
       FIGS. 7-9  illustrate a close up of the distal ends  156 ,  168 , and  180  of the first, second and third elements  152 ,  164 ,  176  respectively. As previously explained, the blade element  158  is available to interoperate against the blunt edge  172  to cut the tendon and the third element  176  provides support for the tendon during the cutting. 
     While the illustrated embodiment has the blade element  158  and the blunt edge  172 , these two may be reversed. That is, in such alternate embodiment, the first element  152  has a blunt edge at the first distal end  156  and the second element  164  has a blade element at the second distal end  168 . 
     While the present disclosure has focused on the secondary cutting implement  150  being used to cut the quadriceps tendon as part of an operation to repair an injury to an ACL, the present disclosure is not so limited. The secondary cutting implement  150  may be used in other graft harvesting operations or for other purposes as needed or desired. 
     Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.