Abstract:
A device for reducing migration of a pin of an intramedullary fixation device, especially to reduce migration of a clavicle pin introduced in the medullary canal of the clavicle to fix a fractured clavicle bone. A clavicle nail with a curved tip is inserted within the medullary canal of the clavicle. The back end of the nail that extends out of the clavicle is provided with indentations or grooves. The back end of the nail is received in a hollow cavity of a cap, which locks onto the indentations or grooves of the nail. A screw is placed through an eyelet of the cap and turned into the clavicle to secure the cap to the clavicle. As a result, the nail is fixed within the medullary canal and undesirable migration of the pin within the medullary canal is reduced.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/168,125, filed on Apr. 9, 2009, the entire disclosure of which is incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to methods and apparatus for surgical procedures and, more particularly, to a locking clavicular device for securing a fracture nail in the collarbone. 
     BACKGROUND OF THE INVENTION 
     Clavicle fractures (also known as broken collarbones) are a common injury. For a long time, the treatment of a clavicle fracture has been simply conservative, non-surgical care (non-operative treatment). Over the last few years, however, various devices such as plates, screws and pins have been developed to aid in the operative treatment of clavicle fractures, reducing the chronic pain, weakness and high nonunion rate typically associated with the non-operative treatment of the clavicle fractures. 
     For example, clavicle plates have been developed to fix broken collarbones by means of a metal plate placed on top of the broken bone and secured in place with screws through the bone. Similarly, intramedullary fixation devices (which have been used primarily for long bones of the legs and arms) have been also developed for clavicle fractures. Pin fixation within the medullary canal of a broken clavicle is often associated, however, with undesirable migration of the pin within the medullary canal. 
     Accordingly, an intramedullary fixation device designed specifically for repairing broken collarbones and for holding the fracture nail in place in the collarbone (without medial and lateral movement) is needed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fixation assembly for repairing clavicle (collarbone) fractures. The clavicle fixation assembly of the present invention includes a clavicle end cap (terminal button or terminal cap) configured to securely capture and retain a fracture nail. The end cap is provided with a retaining device and a clavicular nail receptor (locking mechanism). The retaining device has a through opening to allow a fixation device (for example, a screw) to be inserted through the opening and into the broken clavicle to secure the clavicle fixation assembly to the broken clavicle. 
     The clavicular nail may be provided in incremental diameters between about 1.5 mm to about 3.5 mm. The size chosen is based upon the internal diameter of the patient&#39;s intramedullary canal. The nail is designed with a plurality of circumferential grooves or indentations on one end which will mate with the nail receptor of the end cap. The clavicular nail receptor (locking mechanism) of the end cap is designed with a body (having a cylindrical configuration, for example) provided with a cavity extending partially therethrough. The cavity receives an end of the fracture nail and securely retains the captured fracture nail. To aid in the capturing and retention of the fracture nail, the body of the clavicular nail receptor is provided with a plurality of slots that extend about parallel to the longitudinal axis of the end cap. The slots allow the body of the end cap to “spring” open or flare open when the fracture nail is pressed into the open end of the end cap. After the fracture nail is advanced into the cavity of the end cap, the end cap returns to the initial diameter, and securely captures the fracture nail within one of the grooves in the fracture nail. By providing the slots within the body of the end cap, the nail receptor prohibits any lateral and/or medial movement of the captured fracture nail and prevents both lateral and medial migration of the nail, improving therefore the overall success of the fracture repair and preventing possible physiological damage from an internal loose body. 
     Also provided is an apparatus for surgery including a nail for insertion into a bone having a distal end and a proximal end, the nail having an indentation near the proximal end. The apparatus further includes a retaining device having a circular cross-section with a proximal end and a distal end and a cavity extending from the distal end toward the proximal end, the cavity capable of receiving the proximal end of the nail, the device further having an opening between an inner portion of the cavity and an outer surface of the device, the opening extending from the distal end toward the proximal end of the device. Also the apparatus has a locking mechanism coupled to the distal end of the device, the locking mechanism having a hole that extends through the mechanism and a fastener that extends through the hole of the mechanism to secure the mechanism to the bone. 
     The present invention also provides a method of repair of a clavicle fracture. The method of clavicle repair of the present invention comprises inter alia the steps of: (i) providing a clavicle fixation assembly that includes a clavicle end cap (terminal button or terminal cap) configured to securely capture and retain a fracture nail, the end cap including a retaining device and a clavicular nail receptor (locking mechanism); (ii) inserting the clavicular fracture nail into the broken clavicle until pieces of the broken clavicle are secured adjacent one another; (iii) cutting off (or shortening) the clavicle nail to the proper length based upon the patient&#39;s bone length; (iv) securing the clavicular nail receptor of the end cap (terminal button or terminal cap) at an end of the fracture nail that extends from the clavicle; and (v) inserting a fixation device (for example, a screw or fastener) through an opening of the retaining device of the end cap, and securing the fixation device to the broken clavicle. 
     Also provided is a method of surgery that includes providing a retaining device having a circular cross-section with a proximal end and a distal end and a cavity extending from the distal end toward the proximal end, the device having an opening between an inner portion of the cavity and an outer surface of the device, the opening extending from the distal end toward the proximal end of the device. The method further involves providing a locking mechanism coupled to the proximal end of the device, the mechanism having a hole that extends through the mechanism and providing a nail having a distal end and a proximal end and an indentation near the proximal end. Further including inserting the distal end of the nail into a bone, inserting the proximal end of the nail into the cavity of the device and inserting a fastener through the hole of the mechanism and into the bone to secure the mechanism to the bone. 
     Other features and advantages of the present invention will become apparent from the following description of the invention, which refers to the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1(   a ) and ( b ) illustrates a top view and a cross-sectional view of a clavicle nail assembly of the present invention. 
         FIGS. 2(   a ), ( b ), ( c ), and ( d ) illustrates various views of the end cap (terminal button or terminal cap) of the assembly of  FIG. 1 . 
         FIGS. 3(   a ) and ( b ) illustrates various views of the fracture nail of the assembly of  FIG. 1 . 
         FIG. 4  illustrates the distinct parts of the assembly of  FIG. 1 . 
         FIG. 5  illustrates another view of the assembly of  FIG. 1 . 
         FIG. 6  illustrates a superior view of a broken clavicle bone. 
         FIG. 7  illustrates a superior view of the assembly of  FIG. 1  within a clavicle bone. 
         FIG. 8  illustrates an anterior view of the assembly of  FIG. 1  within a clavicle bone. 
         FIG. 9  illustrates a cross-sectional view of the assembly of  FIG. 1  within a clavicle bone. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following detailed description, reference is made to a specific embodiment in which the invention may be practiced. This embodiment is described with sufficient detail to enable those skilled in the art to practice the invention and it is to be understood that other embodiments may be employed, and that structural and logical changes may be made without departing from the spirit or scope of the present invention. 
     The present invention provides a fixation assembly for fixing clavicle (collarbone) fractures. The clavicle fixation assembly of the present invention includes a clavicle end cap (terminal button or terminal cap) configured to securely capture and retain a fracture nail. The end cap is provided with a retaining device and a clavicular nail receptor. 
     The retaining device is provided with a through opening to allow a fixation device (for example, a screw or fastener) to be inserted through the opening and into the broken clavicle to secure the clavicle fixation assembly to the broken clavicle. 
     The clavicular nail receptor (locking mechanism) of the end cap is designed with a body (having a cylindrical configuration, for example) provided with a cavity extending partially therethrough. The cavity receives an end of the fracture nail and securely retains the captured fracture nail. To aid in the capturing and retention of the fracture nail, the body of the clavicular nail receptor is provided with a plurality of slots that run about parallel to the longitudinal axis of the end cap. The slots allow the body of the end cap to “spring” open or flare open when the fracture nail is pressed into the open end of the end cap. After the fracture nail is advanced into the cavity of the end cap, the end cap returns to the initial diameter and securely captures the fracture nail within one of the grooves in the fracture nail. By providing the slots within the body of the end cap, the nail receptor prohibits any lateral and/or medial movement of the captured fracture nail and prevents both lateral and medial migration of the nail improving the overall success of the fracture repair. 
     The present invention also provides a method of repair of a clavicle fracture. The method of clavicle repair of the present invention will be described in more detail with reference to  FIGS. 6-9 . In an exemplary embodiment only, the method of the present invention comprises inter alia the steps of: (i) providing a retaining device having a circular cross-section with a proximal end and a distal end and a cavity extending from the distal end toward the proximal end, the device having an opening between an inner portion of the cavity and an outer surface of the device, the opening extending from the distal end toward the proximal end of the device; (ii) providing a locking mechanism coupled to the proximal end of the device, the mechanism having a hole that extends through the mechanism; (iii) providing a nail having a distal end and a proximal end and an indentation near the proximal end; (iv) inserting the distal end of the nail into a bone; (v) inserting the proximal end of the nail into the cavity of the device; and (vi) inserting a fastener through the hole of the mechanism and into the bone to secure the mechanism to the bone. 
     Referring now to the drawings, where like elements are designated by like reference numerals,  FIGS. 1-5  illustrate various components of clavicle fixation assembly  100  of the present invention. As shown in the drawings, clavicle fixation assembly  100  includes a clavicle end cap (terminal button or terminal cap)  10  configured to securely capture and retain a fracture nail  50 . A fixation device  80  (for example, a screw or a fastener) is inserted through an opening of end cap (terminal button or terminal cap)  10  and into the broken clavicle, to secure the clavicle fixation assembly  100  to the broken clavicle. 
       FIGS. 2(   a )-( d ) illustrate various views of the end cap (terminal button or terminal cap)  10  of the assembly  100  of  FIG. 1 . End cap  10  is provided with a retaining device  11  and a clavicular nail receptor  13 . As described below, the clavicular nail receptor  13  acts as a locking mechanism for capturing and securely preventing movement of the fracture nail  50  in at least a medial and lateral direction. 
     As shown in  FIGS. 2(   a )-( d ), clavicular nail receptor  13  (locking mechanism  13 ) is provided with a body (having a cylindrical configuration, for example) defining a cavity  16  extending partially therethrough. The cavity  16  has an annular protrusion  14  that extends toward the center of the cavity  16 . The annular protrusion  14  has a circumference that is smaller than the circumference of the cavity  16 . The circumference of the protrusion  14  is approximately equal to the circumference of the indentations  55  on the nail  50  and the width of the protrusion  14  is approximately equal to the width of the indentations  55 . The indentations  55  haves a smaller circumference then the circumference of the nail  50 . Also, the circumference of the cavity  16  is approximately equal to the circumference of the nail  50 . 
     The cavity  16  receives an end  57  of the fracture nail  50  and securely retains the captured fracture nail ( FIGS. 1(   a ) and  1 ( b )). To aid in the capturing and retention of the fracture nail  50 , the body of the clavicular nail receptor  13  is provided with a plurality of slots  15  that extend about parallel to the longitudinal axis  12  of the end cap  10 . The slots  15  allow the body of the end cap to “spring” open or flare open when the fracture nail  50  is pressed into the open end of cavity  16  of the end cap  10 . 
     The body of the end cap flares open because the circumference of the protrusion  14  is smaller than the circumference of the nail  50 . So as the nail  50  is pressed against the protrusion  14 , the body flares open to allow the nail  50  to pass into the cavity  16 . After the fracture nail  50  is advanced into the cavity  16  of the end cap  13  and the protrusion  14  rest within at least one of the grooves or indentations  55  ( FIG. 3(   b )) the end cap returns to its initial circumference, thereby securely capturing the fracture nail  50  within the cavity  16 . Thus, by providing the slots  15  within the body of the end cap the nail receptor  13  may prevent both lateral and medial migration of the nail  50 , thereby improving the overall success of the fracture repair. 
       FIGS. 2(   a )-( d ) also illustrate retaining device  11  of end cap  10 . Retaining device  11  is coupled to an end of clavicular nail receptor  13  and is configured to secure a locking or fixation device  80 . In an exemplary embodiment only, the retaining device  11  is generally cylindrical and has an opening  11   a  extending therethrough. Opening  11   a  is configured to receive fixation device (screw)  80 , as shown in  FIGS. 1(   a ) and  1 ( b ), for example. Fixation device (screw)  80  is inserted through opening  11   a  and then is secured into the broken clavicle, thereby affixing the locking assembly  100  to the broken clavicle. In an exemplary embodiment, fixation device (screw)  80  is inserted through opening  11   a  so that the longitudinal axis  80   a  of the fixation device (screw)  80  is about perpendicular to the longitudinal axis  17  of the clavicular nail receptor  13 . 
       FIGS. 3(   a ) and  3 ( b ) illustrate various views of the fracture nail  50  employed with clavicle assembly  100  of the present invention. End  53  of the nail  50  may be provided with a bent region (as shown in  FIG. 3(   a )) to facilitate entry of the nail into the clavicle. Specifically, the bent region  53  enables the end of the clavicle nail to tunnel into the clavicle by twisting the nail, thereby easing the insertion of the nail. Preferably, nail  50  is inserted into the clavicle until broken pieces of the clavicle are held securely adjacent one another via nail  50 . A second end  57  of nail  50  remains exposed at the location where nail  50  was inserted into the clavicle. The second end  57  is captured and secured within cavity  16  of the clavicular nail receptor  13  (locking mechanism  13 ). If the second end  57  protrudes too far past the entry hole into the broken clavicle, the nail may be cut to the proper length anywhere within the grooved or indented area  55  of the nail so that the nail may still be captured within the cavity  16  of the clavicle nail receptor  13 . 
     The clavicular nail  50  is generally flexible, but rigid in the axial plane, and may be manufactured from biocompatible materials such as titanium or titanium alloy, among many others. The nail  50  is preferably flexible to enable bending to accommodate a shape of the clavicle while being inserted through the clavicle. The nail  50  may also be fabricated from a material having the requisite strength to support the clavicle as the clavicle heals. Nail  50  also has a length and diameter that is sufficient for insertion through the clavicle. It should be understood by one of ordinary skill in the art that the size of nail  50  varies depending on its use and a size of the patient receiving the nail  50 . 
     The present invention also provides a method of repair of a clavicle fracture as shown in  FIGS. 6-9 .  FIG. 6  shows a superior view of a clavicle  200  with a lateral end  202  and a medial end  204 . The clavicle  200  has a fracture  210 . The method of clavicle repair of the present invention is detailed below: 
     A clavicle fixation assembly  100  is provided that includes a clavicle end cap (terminal button or terminal cap)  10  configured to securely capture and retain a fracture nail  50 , the end cap  10  including a retaining device  11  and a clavicular nail receptor (locking mechanism)  13 . 
     The clavicular fracture nail  50  is inserted into the broken clavicle  200  in the insertion point  220  and passes through the clavicle  200  along path  230  ( FIG. 6 ). After the nail  50  passes into the lateral end  202  of the bone, the fracture nail  50  is twisted until fragments of the broken clavicle are secured adjacent one another. 
     Next, the clavicular nail receptor  13  of the end cap (terminal button or terminal cap)  10  is secured to an end of the fracture nail  50  that extends from the clavicle  200  as shown in  FIGS. 7-9 . 
     Next, a fixation device (for example, a screw or a fastener)  80  is inserted through an opening  11   a  of the retaining device  11  of the end cap  10 , and the fixation device  100  is secured to the broken clavicle  200  as shown in  FIGS. 7-9 . 
     The above description and the drawings illustrate only exemplary and/or preferred embodiments which achieve the objects, features and advantages of the present invention. It is not intended that the present invention be limited to the illustrated embodiments.