Abstract:
A femoral intramedullary rod system capable of treating a variety of femoral bone fractures using a uniform intramedullary rod design. The system generally comprising an intramedullary rod defining an opening having an upper surface and a transverse member including a bone engaging portion and a connection portion defining a thru-hole with the nail sized to pass therethrough. A pin is selectively coupled to the transverse member to rigidly assemble the transverse member to the nail when the nail is passed through the thru-hole and the pin is received within the opening.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to techniques for treating bone fractures. Specifically, but not exclusively, the invention relates to a system for treating a variety of typical femoral fractures using a uniform intramedullary rod design. 
     BACKGROUND OF THE INVENTION 
     The femur generally comprises an elongated shaft extending from the hip to the knee. The proximal end of the femoral shaft includes a neck segment connected to a head portion. The head portion fits into a concavity of the hip bone to form a ball and socket joint at the hip. The distal end of the femoral shaft engages the upper end of the tibia to form the knee joint. Overall, the femur is one of the longest and strongest bones in the human body; however, portions of the femur are extremely susceptible to fracture. 
     Internal fixation of femoral fractures is one of the most common orthopedic surgical procedures. Many different types of femoral fractures are encountered in practice, including fractures of the femoral neck, midshaft, and distal regions. When the femur is fractured, treatment requires that the fractured bone be substantially immobilized and held together in an abutting relationship during the healing process. Any longitudinal, transverse, or rotational movement of one section of the fractured bone relative to the other can cause substantial delay in healing time or cause improper healing to occur. In general, two different internal fixation approaches have been used to immobilize the area surrounding the fracture site. 
     One approach involves driving metallic pins through the two sections of bone to be joined and connecting them to one or more plates bearing against the external surface of the bones. However, such an arrangement injures the flesh and muscle surrounding the bones and a large number of pins driven through the bone tend to weaken its hard outer layer. Plates also tend to stress the bone and are not always able to bear sufficient stress for many femoral fracture applications. 
     Further, bone beneath the plate does not always become as strong as it would in the absence of the plate. A second approach to treating femoral fractures involves the use of an intramedullary nail which is inserted into the medullary canal of the femur and affixed therein by a number of different methods. After complete healing of the bone at the fracture site, the nail may be removed through a hole drilled in the proximal end of the femur. A wide variety of devices have been developed over the years for use in the internal fixation of femoral fractures utilizing the method of intramedullar stabilization and immobilization. While there have been a number of technological advances made within the area of intramedullary fixation of femoral fractures, several problem areas remain. 
     One such problem arises from the fact that most intramedullary fixation systems currently available are adapted to a specific type of femoral fracture, resulting in a large number of highly specialized configurations. This has led to the disadvantageous consequence that hospitals and trauma centers have to keep a large inventory of incremental nail lengths with varying configurations and ancillary parts in order to accommodate a random and diverse incoming patient population. Maintaining such a high level of inventory to handle all expected contingencies is not only complex, but is also very expensive. Correspondingly, the possibility of error during selection and implantation of the fixation device by the surgeon is elevated. Likewise, the inventory costs associated with varying methods of intramedullary fixation are drastically increased and, in the case of smaller medical facilities, may necessitate switching to a less costly and potentially less effective method of treating femoral fractures. 
     Another problem may result from intramedullary rod systems used to specifically treat fractures of the neck or head of the femur. These devices typically include a transverse fixation member (nail, pin, screw, etc.) adapted to be positioned along the longitudinal axis of the femoral neck with its leading end portion embedded in the femoral head so as to grip the femoral head and thereby stabilize the fracture site. The fixation member is operably connected to the intramedullary rod to maintain a fixed relationship between the fixation member and the rod. Unfortunately, this structural connection does not always prevent rotational or translational movement of the fixation member relative to the intramedullary rod in response to forces commonly resulting from the normal activity of a convalescing patient. Additionally, the intramedullary rods used in these devices are typically specialized for use with this single fixation application and can not be used in other applications. Therefore, the costs associated with maintaining increased levels of inventory are substantially increased. Furthermore, if it is desired to vary the angle of the fixation member relative to the rod, substantial modifications must typically be made to either the fixation member or the rod member to accommodate for such an angular variation, again driving up inventory levels and associated inventory costs. 
     In still another problem area, on occasion, it is necessary to use transverse locking bone screws to lock the rod into position relative to the femur. In order to prevent the screws from backing out, locking nuts can be threaded onto the distal ends of the locking screws. Unfortunately, the installation of locking nuts onto the ends of the locking screws requires additional surgical incisions and commonly causes soft tissue irritation. 
     In yet another problem area, when an intramedullary rod is inserted into the medullary canal and anchored to the femur by two or more bone screws, despite the best efforts of the surgeon, the fracture site may have either been over-compressed or over-distracted as a result of the insertion of the rod. Unfortunately, with conventional intramedullary rods, it is virtually impossible to adjust the amount of distraction or compression without first removing one or more of the bone screws and manually distracting or compressing the fracture site. The intramedullary rod must then be re-anchored to the femur by reinserting the bone screws at different positions along the femur. 
     Thus, there is a demand for bone treatment techniques to address these problems. The present invention meets this demand and provides other benefits and advantages in a novel and unobvious manner. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to techniques for treating bone fractures. Various aspects of the invention are novel, nonobvious and provide various advantages. While the actual nature of the invention covered herein can only be determined with reference to the claims appended hereto, selected forms and features of the preferred embodiment as disclosed herein, are described briefly as follows. 
     One form of the present invention includes treating a bone fracture with a nail that defines an opening and a transverse member including a bone engaging portion and a connection portion. The connection portion defines a through-hole and the nail is sized to pass through the through-hole. A pin is adjustably coupled to the transverse member to rigidly assemble the transverse member to the nail. 
     In a further form of the present invention, a method of treating a bone fracture includes forming a first hole in a femur transverse to the medullary canal and introducing a transverse member through the first hole. The transverse member includes a through-hole that is positioned relative to the medullary canal of the femur, and is preferably aligned therewith. The method further includes forming a second hole intersecting the medullary canal and inserting an intramedullary nail into the medullary canal via the second hole. The nail passes through the through-hole of the transverse member. The nail may include an opening aligned with the transverse member to facilitate rigid assembly to the transverse member by positioning a pin coupled to the transverse member in the nail opening. 
     In still another form of the present invention, a system for treating bone fractures includes a nail having a first end portion opposite a second end portion along a longitudinal axis. The first end portion defines an opening extending through the nail and has an angled surface oriented at an oblique angle relative to the longitudinal axis of the nail. Also included is a sleeve that includes a pair of apertures positioned on opposite sides of the sleeve. The apertures and the opening align to form a passageway when the sleeve is fitted over an end portion. A bone engaging member is received within the passageway in an abutting relationship with the angled surface. 
     In yet another form of the present invention, a bone fracture treatment apparatus includes an elongated nail having a longitudinal axis and a transverse axis generally perpendicular to the longitudinal axis. The nail defines a transverse opening extending along the transverse axis with the opening being bound by an upper surface and an opposite lower surface. At least one of the upper or lower surface defines a projection extending in a longitudinal direction to thereby narrow a dimension of the opening within the nail. The nail opening, and projection may be arranged to cooperate with one or more other members suitable to treat a particular type of bone fracture, such as a fracture of the femur. 
     According to another form of the present invention, a system for treating bone fractures includes a nail defining a longitudinal axis, a transverse axis and an opening extending along the transverse axis with the opening being bound by a bearing surface. Also included is a sleeve having a pair of apertures positioned on opposite sides thereof. The apertures and the opening are aligned to form a passageway when the sleeve is fitted over the nail. A bone engaging member is sized to pass through the passageway. Additionally, the system may include a means for biasing the sleeve in a longitudinal direction to clamp the bone engaging member against the bearing surface. 
     Still a further form of the present invention includes a technique for treating bone fractures with a nail that defines a longitudinal axis, an elongated opening extending therethrough, and a longitudinal passage intersecting the opening. A bone engaging member passes through the opening and a positioning device is provided that may be adjusted to change position of the bone engaging member along the longitudinal axis relative to the nail when the member is positioned through the nail opening. This device may be utilized to facilitate compression or distraction of a bone fracture. 
     Accordingly, one object of the present invention is to provide an improved bone fracture treatment system. Preferably, this system may be used to treat fractures of the femur. 
     Additionally or alternatively, another object is to provide an improved method of treating bone fractures, particularly fractures of elongated bones such as the femur. 
     Additionally or alternatively, still another object is to reduce the complexity and inventory costs associated with treating bone fractures. 
     Other objects, features, forms, embodiments, aspects, advantages and benefits of the present invention will become apparent to persons of ordinary skill in the art from the following written description and accompanying figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view, partly in section, of a rod system of the present invention with a transverse member shown in an antegrade position. 
     FIG. 2 is a side view, partly in section, of the system of FIG. 1 with the transverse member in a retrograde position. 
     FIG. 3 is a partial side view of the proximal end portion of the rod of FIGS. 1 and 2. 
     FIG. 4 is a partial side view of the sleeve of FIGS. 1 and 2. 
     FIG. 5 is a partial, sectional side view of the proximal end portion of the rod shown in FIG.  3  and the sleeve of FIG. 4 assembled together with the locking member of FIGS. 1 and 2. 
     FIG. 6 is a side view, partly in section, of another rod system of the present invention implanted in the neck and head of a femur. 
     FIG. 7 is a partial, sectional side view of the proximal end portion of the system of FIG.  6 . 
     FIG. 8A is a side view of the fixed angle pin of FIG.  7 . 
     FIG. 8B is an end view of the fixed angle pin of FIG.  7 . 
     FIG. 9 is a partial, sectional side view of the proximal end of yet another system of the present invention having a variable angle pin positioned at 135 degrees relative to a rod. 
     FIG. 10A is a side view of the leading portion of the variable angle pin of FIG.  9 . 
     FIG. 10B is an end view of the leading portion of the variable angle pin of FIG. 9 taken along view line  10 B— 10 B of FIG.  10 A. 
     FIG. 11A is a side view of the trailing portion of the variable angle pin of FIG.  9 . 
     FIG. 11B is an end view of the trailing portion of the variable angle pin of FIG. 9 taken along view line  11 B— 11 B of FIG.  11 A. 
     FIG. 12 is a partial, sectional side view of the proximal end of the system of FIG. 9 showing the variable angle pin at 140 degrees relative to the rod. 
     FIG. 13 is a side view, partly in section, of still another rod system of the present invention illustrating implantation of an intramedullary nail inserted in a retrograde direction. 
     FIG. 14 is a partial, sectional side view of the proximal end portion of a further system of the present invention. 
     FIG. 15 is a side view, partly in section, of another rod system of the present invention for performing distraction of a bone fracture. 
     FIG. 16 is a partial, sectional side view of the proximal end portion of the rod of FIG.  15 . 
     FIG. 17 is a partial, sectional side view of the proximal end portion of the system of FIG. 15, illustrating a first operational position. 
     FIG. 18 is a partial, sectional side view of the proximal end portion of the system of FIG. 15, illustrating a second operational position. 
     FIG. 19 is a side view, partly in section, of an additional intramedullary rod system of the present invention for performing compression of a bone fracture. 
     FIG. 20 is a partial, sectional side view of the proximal end portion of the system of FIG. 19, illustrating a first operational position. 
     FIG. 21 is a partial, sectional side view of the proximal end portion of the system of FIG. 19, illustrating a second operational position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, any alterations and further modifications in the illustrated embodiments, and any further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     FIGS. 1-2 depict intramedullary system  10  according to one embodiment of the present invention. System  10  is shown implanted in femur  12  and includes an elongated intramedullary rod or nail  14 , sleeve  16  and bone engaging member  18 . System  10  also includes fasteners  20  and locking bone screws  22   a ,  22   b . FIG. 1 illustrates system  10  as used in a first locking configuration with bone engaging member  18  placed in an antegrade direction within femur  12 . FIG. 2 illustrates a second locking configuration of system  10 ; where bone engaging member  18  is placed in a retrograde position within femur  12 . The tip of the greater trochanter  12   a , the neck  12   b , and the head  12   c  of femur  12  are designated in FIGS. 1 and 2. Although system  10  is shown implanted in a human femur  12 , system  10  could also be used in conjunction with other bones as would occur to one skilled in the art, including, but not limited to, the tibia, humerus, radius, ulna and fibula. 
     Nail  14  includes a proximal end portion  14   a  and a distal end portion  14   b . Nail  14  also defines a longitudinal centerline axis L 1  running along the length of nail  14  between proximal end portion  14   a  and distal end portion  14   b . For application to an adult human femur, proximal end portion  14   a  preferably has a diameter of about 11-13 millimeters. The diameter of the remainder of nail  14  may vary depending upon the requirements of the fixation procedure and the surgeon&#39;s preference. While nail  14  has a generally circular cross section, other suitable shapes are also contemplated as would occur to one skilled in the art. 
     Referring additionally to FIGS. 3-5, portion  14   b  of nail  14  defines generally parallel transverse bores  24   a ,  24   b , each sized to respectively receive locking bone screws  22   a ,  22   b  therein. Distal end portion  14   b  also defines transverse bore  24   c,  aligned generally perpendicular to transverse bores  24   a ,  24   b  and sized to receive locking bone screw  22   c  (not shown). Proximal end portion  14   a  defines an opening  26  and a threaded transverse bore  28 , both extending through nail  14  generally transverse to axis L 1  from a first side  14   c  to a second side  14   d . Side  14   c  generally opposes side  14   d . Proximal end portion  14   a  also defines threaded longitudinal bore  29  generally extending along axis L 1  for receiving nail insertion and extraction instrumentation (not shown) used to guide nail  14  into and out of femur  12 . Nail  14  also defines a longitudinal passage  30  intersecting bore  29  and extending generally along axis L 1  to allow for the optional use of a guide wire (not shown) to aid in the insertion of nail  14  into femur  12 . 
     Referring more specifically to FIGS. 3 and 5, opening  26  is bound by lower surface  31  opposite upper surface  32 . Lower surface  31  includes a first angled surface  31   a  oriented generally parallel to transverse axis T 1 . Upper surface  32  includes a second angled surface  32   a  offset from first angled surface  31   a  along axis T 1 . Angled surfaces  31   a ,  32   a  are generally parallel to transverse axis T 1 . Transverse axis T 1  is aligned at an oblique angle α 1  relative to longitudinal axis L 1  of nail  14 . Angle α 1  is preferably in a range of about 120-150 degrees, with the more preferred angle being about 135 degrees. First angled surface  31   a  and second angled surface  32   a  cooperate to define pathway  33  generally oriented at angle α 1  relative to axis L 1 . First pathway  33  is sized to receive bone engaging member  18  therethrough. 
     Lower surface  31  also includes a third angled surface  31   b  aligned generally parallel to transverse axis T 2 . Upper surface  32  also includes a fourth angled surface  32   b  generally offset from third angled surface  31   b  along axis T 2  that is also generally parallel to transverse axis T 2 . Comparing to FIG. 2, transverse axis T 2  is also aligned at an oblique angle α 2  relative to longitudinal axis L 1  of nail  14 . Angle α 2  is preferably in a range of about 120-150 degrees, with the more preferred angle being about 135 degrees. Third angled surface  31   b  and fourth angled surface  32   b  cooperate to define pathway  34  generally oriented at angle α 2  relative to axis L 1 . Second pathway  34  is sized to receive bone engaging member  18  therethrough. 
     First angled surface  31   a  and third angled surface  31   b  cooperate to define a first projection  35  extending in a longitudinal direction which narrows a dimension of opening  26  within nail  14  along axis L 1 . Similarly, second angled surface  32   a  and fourth angled surface  32   b  cooperate to define a second projection  36  extending in a longitudinal direction generally opposite first projection  35  to further narrow a dimension of opening  26  within nail  14  along axis L 1 . In a preferred embodiment, each projection  35 ,  36  defines an apex, resulting in a convergent-divergent throat  36   a  about midway between sides  14   c  and  14   d  of nail  14 . However, first projection  35  and second projection  36  could alternatively define any other geometric configuration as would occur to those skilled in the art. For example, first projection  35  and second projection  36  could be rounded. Likewise, in other alternative embodiments, one or more of projections  35 ,  36  may be absent. While angled surfaces  31   a ,  31   b ,  32   a ,  32   b  are generally concave to compliment member  18 , other shapes are also contemplated as would occur to those skilled in the art. For example, angled surfaces  31   a ,  31   b ,  32   a ,  32   b  could be flat or have other configurations corresponding to the outer surface of bone engaging member  18 . 
     Referring to FIG. 4, sleeve  16  of system  10  is illustrated therein. Sleeve  16  has a generally cylindrical shape and defines a proximal end  16   a , a distal end  16   b  and a side wall  37 . Sleeve  16  is sized to fit over the proximal end of nail  14  as shown in FIG.  3 . Distal end  16   b  is therefore open to allow for passage of proximal end portion  14   a  therethrough. Sleeve  16  also defines an inwardly tapered edge  38 , terminating at distal end  16   b , to permit easy sliding of sleeve  16  through bone. Proximal end  16   a  defines an opening  39  to permit access to threaded bore  29 , and thus allow for passage of nail insertion and extraction instrumentation (not shown). Side wall  37  defines offset apertures  40   a ,  40   b  positioned on opposite sides of sleeve  16 . Apertures  40   a ,  40   b  are generally circular and are aligned and sized to receive bone engaging member  18  therethrough. Side wall  37  further defines opposing transverse apertures  42   a ,  42   b  positioned on opposite sides of sleeve  16 . Apertures  42   a ,  42   b  are generally circular and are aligned and sized to receive fastener  20  therethrough. 
     Referring to FIG. 5, therein is illustrated bone engaging member  18 . Bone engaging member  18  includes a proximal end portion  18   a  and a distal end portion  18   b . Bone engaging member  18  has a generally circular cross section and preferably has a diameter of about 5.5-6.5 millimeters for applications treating fractured adult human femurs. Distal end portion  18   b  includes a means for fixedly engaging and gripping bone  44 . Bone engaging member  18  may be a bone screw having a threaded distal end portion  18   b  as shown in FIG. 5, or a bone blade having distal end portion  18   b  formed from a plate with a helical twist (not shown). Alternately, distal end portion  18   b  may be otherwise configured for engaging bone as would occur to those skilled in the art. 
     As illustrated in FIG. 5, when sleeve  16  is fitted over proximal end portion  14   a  of nail  14 , apertures  40   a ,  40   b  of sleeve  16  are positioned to align with opening  26  of nail  14 , and register with pathway  33  along transverse axis T 1 . Collectively, apertures  40   a ,  40   b  and opening  26  define passageway  50  coincident with pathway  33 . Passageway  50  is bound on one side by first angled surface  31   a  and on another side by second angled surface  32   a . As bone engaging member  18  is slidably received within passageway  50  and guided along transverse axis T 1 , bone engaging member  18  forms an abutting relationship with either or both of first and second angled surface  31   a ,  32   a . This relationship may be load bearing in nature. Bone engaging member  18  is sized relative to passageway  50  so that its rotational position about axis L 1  and its translational position along axis L 1  are generally fixed when positioned therethrough. 
     As illustrated in FIG. 5, when sleeve  16  is fitted over proximal end portion  14   a  of nail  14 , apertures  42   a ,  42   b  of sleeve  16  are aligned with bore  28  of nail  14 . A fastener  20  is passed through aperture  42   a  and threaded into bore  28  to thereby releasably secure sleeve  16  to nail  14 . Another fastener  20  is passed through aperture  42   b  and threaded into bore  28  to further secure sleeve  16  to nail  14 . While two fasteners  20  are shown to releasably secure sleeve  16  to nail  14 , it is also contemplated that a single fastener may be used to sufficiently secure sleeve  16  to nail  14 . To avoid interfering with the optional use of a guide wire (not shown) to aid in the insertion of nail  14  into femur  12 , fastener  20  has a length which penetrates bore  28  far enough to secure sleeve  16  to nail  14 , but without obstructing longitudinal passage  30 . In still other embodiments, one or more of fasteners  20 , bore  28 , and apertures  42   a ,  42   b  may not be utilized at all. 
     Notably, by rotating sleeve  16  180 degrees relative to nail  14 , system  10  may be reconfigured from an antegrade orientation of bone engaging member  18  to a retrograde orientation, or vice-versa. Similarly, regardless of which locking configuration is used, the same components of system  10  can be used to treat either a left or right femur by simply rotating sleeve  16  180 degrees relative to nail  14 . As a result, apertures  40   a ,  40   b  of sleeve  16  are repositioned to align with pathway  34  through opening  26  of nail  14  along transverse axis T 2 . Collectively, apertures  40   a ,  40   b  and opening  26  define passageway  52  which is coincident with pathway  34 . Passageway  52  is bound on one side by third angled surface  31   b  and on another side by fourth angled surface  32   b  (see FIGS.  2  and  5 ). As bone engaging member  18  is slidably received within passageway  52  and guided along transverse axis T 2 , bone engaging member  18  forms an abutting relationship with either or both of the third and fourth angled surfaces  31   b ,  32   b . Preferably, this relationship is suitable for load bearing, and generally fixes member  18  with respect to rotation about axis L 1  or translation along axis L 1  . 
     In other embodiments of system  10 , the angular alignment of bone engaging member  18  relative to axis L 1  may be varied by changing the configuration of sleeve  16 . More specifically, apertures  40   a ,  40   b  can be aligned at an angle other than α 1 . In these embodiments, first passageway  50  does not fall along transverse axis T 1  of nail  14 . Thus, as bone engaging member  18  is slidably received within first passageway  50 , bone engaging member  18  will contact either first projection  35  or second projection  36 , but will not form an abutting relationship with first angled surface  31   a  or second angled surface  32   a . However, the alternative arrangement is still suitable to fix bone engaging member  18  axially and rotationally relative to nail  14 . 
     Referring again to FIGS. 1 and 2, a femur implantation procedure corresponding to system  10  is next described. The implant procedure generally includes forming a longitudinal hole into, and generally parallel with, the medullary canal from a position slightly medial to the tip of the greater trochanter  12   a . The longitudinal hole is sized to receive nail  14  therethrough. Preferably, the longitudinal hole is formed by drilling. Sleeve  16  is fitted over proximal end portion  14   a  of nail  14  and sleeve  16  is secured to nail  14  by threading fasteners  20  into bore  28 . As discussed above, system  10  can be used in either a first or second locking configuration depending on the rotational orientation of sleeve  16  relative to nail  14 . 
     FIG. 1 illustrates system  10  in a first locking configuration corresponding to an antegrade configuration for the depicted femur  12 . In this first locking configuration, sleeve  16  is secured to nail  14  with apertures  40   a ,  40   b  positioned relative to opening  26  of nail  14  to define passageway  52  along transverse axis T 2 . Nail  14 , with sleeve  16  secured thereto, is inserted through the longitudinal hole and into the medullary canal. A transverse hole is formed through femur  12  across the medullary canal corresponding to transverse axis T 2 . The transverse hole intersects the medullary canal and is sized to receive bone engaging member  18  therein. Preferably this transverse hole also is formed by drilling. Bone engaging member  18  is inserted into the transverse hole and through passageway  52  formed by nail  14  and sleeve  16 . As a result, member  18  is preferably secured against translation along axis L 1  or rotation about axis L 1 . When received in passageway  52 , member  18  generally extends between a femur entry point slightly lateral to the greater trochanter  12   a  to a terminal point below the base of neck  12   b . Generally parallel bores are formed through femur  12  transverse to the medullary canal and generally perpendicular to axis L 1  to align with transverse bores  24   a ,  24   b  of nail  14 . Preferably these bores are also formed by drilling. Nail  14  is further locked into position by inserting locking bone screws  22   a ,  22   b  through femur  12  and into transverse bores  24   a ,  24   b  of nail  14 . 
     FIGS. 2 and 5 illustrates system  10  in a second locking configuration corresponding to a retrograde arrangement relative to the depicted femur  12 . In this second locking configuration, sleeve  16  is secured to nail  14  with apertures  40   a ,  40   b  positioned relative to opening  26  of nail  14  to define passageway  50  along transverse axis T 1 . The medullary canal is accessed in generally the same manner as described in connection with FIG.  1 . Nail  14 , with sleeve  16  secured thereto, is inserted through the longitudinal hole medial to the greater trochanter  12   a  and into the medullary canal. A transverse hole is drilled into femur  12  across the medullary canal corresponding to transverse axis T 1  and sized to receive bone engaging member  18  therein. Bone engaging member  18  is inserted into the transverse hole through passageway  50 . So arranged, member  18  generally extends through neck  12   b  into head  12   c . Generally parallel bores are formed through femur  12  transverse to the medullary canal and generally perpendicular to axis L 1 . These bores are generally aligned with transverse bores  24   a ,  24   b  of nail  14 . Nail  14  is further locked into position by inserting locking bone screws  22   a ,  22   b  through femur  12  and into transverse bores  24   a ,  24   b  of nail  14 . 
     Next, a preferred method of manufacturing nail  14  is described. This preferred method includes drilling a first bore through proximal portion  14   a  in a direction corresponding to transverse axis T 1  (aligned at angle α 1 ). A second bore is then drilled through proximal portion  14   a  corresponding to transverse axis T 2  (aligned at angle α 2 ) and intersecting the first bore at a point generally corresponding to the centerline of nail  14 . The first and second bores are each sized to receive bone engaging member  18  therethrough. The first bore thereby defines first angled surface  31   a  and second angled surface  32   a , and the second bore thereby defines third angled surface  31   b  and fourth angled surface  32   b . The remaining material between lower surface  31  and upper surface  32  may then be removed to form opening  26  through nail  14 , having projections  35 ,  36  as depicted. 
     FIG. 6 depicts intramedullary system  100  according to another embodiment of the present invention; where like reference numerals represent like features previously described in connection with system  10 . System  100  is shown implanted in femur  12  and includes intramedullary rod or nail  14 , transverse member  102 , pin  103 , locking screw  104  and set screw  105 . System  100  also includes locking bone screws  22   a ,  22   b . Although system  100  is shown implanted in human femur  12 , system  100  could also be used in conjunction with other bones as would occur to one skilled in the art, including the tibia, humerus, radius, ulna and fibula to name a few. While system  100  could be used to treat the same indications as system  10  in the second locking configuration, as illustrated in FIG.  2  and discussed above, it is preferably used for fractures of the proximal portion of femur  12 , and more preferably fractures between the neck  12   b  and head  12   c . The same components of system  100  can be used to treat either a left or right femur by rotating transverse member  102  180 degrees relative to nail  14 . 
     FIGS. 7-12 provide additional details concerning the structure and assembly of system  100 . Referring to FIG. 7, various structural details of transverse member  102  and pin  103  are shown therein. Transverse member  102  defines a longitudinal centerline axis L 2  and includes a barrel connection portion  106  and a bone engaging portion  108 . Connection portion  106  is generally cylindrical and has a side wall  110 . Side wall  110  defines a passage  112  extending generally along axis L 2 . Connection portion  106  also includes a proximal portion  106   a  and a distal portion  106   b . Proximal portion  106   a  includes an internal threaded portion  114  extending along a portion of passage  112 . Distal portion  106   b  defines an external inward taper  116  to promote ease of movement through bone when transverse member  102  is advanced into femur  12 . Distal portion  106   b  also defines an inner retaining lip  118  for provisionally maintaining bone engaging portion  108  in sliding engagement with connection portion  106 , the operation of which will become apparent hereinafter. 
     A thru-hole  120  is formed through connection portion  106 . Thru-hole  120  is generally cylindrical and has a diameter slightly greater than the outer diameter of proximal portion  14   a  of nail  14 . Alternately, thru-hole  120  could be elliptical or any other shape corresponding to proximal portion  14   a  of nail  14 . Additionally, thru-hole  120  and portion  14   a  of nail  14  could be asymmetrical and of similar profile to prevent rotational movement of transverse member  102  relative to nail  14  when proximal portion  14   a  is received within thru-hole  120 . Similarly, if thru-hole  120  and portion  14   a  of nail  14  where both tapered in the same direction and at about the same angle, the resulting tight engagement between transverse member  102  and nail  14  would aid in preventing rotational movement. 
     Thru-hole  120  is formed through connection portion  102  to provide a selected angular relationship with axis L 1  when nail  14  passes therethrough. This relationship corresponds to angle α 3  between axes L 1  and L 2 , and is preferably in a range of about 130-145 degrees. More preferably, for system  100 , angle α 3  is about 135 degrees and is equal to angle α 2  as depicted in FIG.  6 . As will become apparent from later discussion, angle α 3  corresponds to the angle of fixation between transverse member  102  and nail  14 . 
     Bone engaging portion  108  includes a proximal portion  108   a  and a distal portion  108   b.  A bone engaging and gripping thread  122  is formed on distal portion  108   b.  Additionally or alternatively, a different bone gripping means may be utilized, such as a bone blade having distal portion  108   b  formed from a plate with a helical twist, or such other means as would occur to those skilled in the art. 
     Proximal portion  108   a  includes a hex recess  124  for receiving a driving tool (not shown), such as an Allen wrench, preferably suited to drive bone engaging portion  108  into neck  12   b  and head  12   c  of femur  12 . Bone engaging portion  108  defines a longitudinal passage  126  extending therethrough and generally along axis L 2  to allow for the optional use of a guide wire (not shown) to aid in the insertion of bone engaging portion  108  into bone. Proximal portion  108   a  is sized to be received within passage  112  of connection portion  106  to allow slidable movement of bone engaging portion  108  generally along axis L 2  over a predetermined range. A keeper  128  is provided on, in association with, or integral to proximal portion  108   a  to provisionally maintain bone engaging portion  108  and connection portion  106  in a telescopic sliding relationship. Keeper  128  is comprised of a cylindrical sleeve that is preferably laser welded onto shaft  130  of bone engaging portion  108  after it has been positioned within connection portion  106 . The outer diameter of keeper  128  is slightly smaller but in close tolerance with the inner diameter of passage  112 . 
     Pin  103  is shown positioned within passage  112  of connection portion  106 . FIGS. 8A and 8B additionally illustrate various structural details of pin  103 . Pin  103  has a longitudinal centerline axis L 3  and includes a leading portion  132  integrally connected to a trailing portion  134 . Leading portion  132  has a generally circular, elongated body and is sized to be received within opening  26  of nail  14 . Leading portion  132  also includes an angled, annular engaging surface  135  configured to co-act with a surface of nail  14 . Engaging surface  135  is aligned at an angle α 4  relative to axis L 3 . Angle α 4  is in a range of about 130-145 degrees. Most preferably, angle α 4  should be approximately equal to angle α 2 . Leading portion  132  additionally includes a tapered tip  136 . Trailing portion  134  is provided with an externally threaded portion  137  configured to threadedly engage threaded portion  114  of connection portion  106 . A hex recess  138  is defined by trailing portion  134  for receiving a driving tool (not shown), such as an Allen wrench, to advance pin  103  into portion  106  or remove pin  103  from portion  106  by turning in a corresponding rotational direction. In other embodiments, pin  103  additionally or alternatively has a different means for positioning relative to connection portion  106 , such as a ratcheting mechanism, a cabling arrangement, or any other method capable of advancing pin  103  along axis L 2  as would occur to those skilled in the art. 
     In order to prevent pin  103  from migrating once positioned in a desired position within passage  112 , system  100  includes locking screw  104 . Locking screw  104  is provided with external threads  142  configured to threadedly engage threaded portion  114  of connection portion  106 . A hex recess  144  is defined by trailing end  146  for receiving a driving tool (not shown), such as an Allen wrench, to rotationally advance locking screw  104  along connection portion  106 . Locking screw  104  is axially advanced along axis L 2  until it tightly engages trailing portion  134  of pin  103 . In other embodiments, system  100  additionally or alternatively includes another locking means as would normally occur to one skilled in the art to prevent pin  103  from migrating relative to connection portion  106 . 
     To further aid in preventing pin  103  from rotating, loosening or migrating once positioned in a desired axial position within passage  112 , system  100  includes set screw  105 . Set screw  105  includes a threaded portion  150  and an elongated stem portion  152 . Threaded portion  150  is configured to threadedly engage bore  29  of nail  14 . Threaded portion  150  also includes a hex recess  154  for receiving a driving tool (not shown), such as an Allen wrench, to rotationally advance set screw  105  along bore  29 . Elongated stem portion  152  is sized to be slidably received within longitudinal passage  30  of nail  14 . Stem  152  also defines a tapered or contoured end  156  conforming with an outer surface of leading portion  132  of pin  103  to provide improved mechanical interlocking between set screw  105  and pin  103 . 
     Referring generally to FIGS. 6,  7 ,  8 A, and  8 B, another embodiment of a femur implantation procedure in accordance with the present invention is described with respect to system  100 . This femur implantation procedure generally includes forming a transverse passage into femur  12  that crosses the medullary canal and is sized to receive transverse member  102  therein. Preferably, this transverse passage is formed by drilling and begins at the lateral side of femur  12 , extends into neck  12   b  and terminates in head  12   c  to orient transverse member  102  as depicted in FIG.  6 . Also shown in FIG. 6, it is preferred that the transverse passage form an oblique angle approximately the same as angle α 3  with respect to axis L 1  or the medullary canal. 
     Next, transverse member  102  is introduced through the transverse passage with thru-hole  120  positioned to at least overlap the medullary canal of femur  12 , and preferably to be generally centered with respect to the medullary canal of femur  12 . At least a portion of bone engaging portion  108  is threaded into femur  12  at this stage. Preferably, bone engaging portion  108  is threaded into a portion of head  12   c  of femur  12  by engaging hex recess  124  with a suitable tool and turning portion  108  in a corresponding rotational direction generally about axis L 2 . 
     Notably, bone engaging portion  108  is telescopically received within passage  112  of connection portion  106  to allow axial movement of bone engaging portion  108  over a predetermined range along axis L 2 . Keeper  128  cooperates with inner retaining lip  118  to prevent disengagement of bone engaging portion  108  from connection portion  106 . The cooperation between inner retaining lip  118  and keeper  128  also acts to stabilize bone engaging portion  108 , thus aiding in the sliding motion of bone engaging portion  108  to provide the preferred telescopic functioning of transverse member  102 . Since connection portion  106  provisionally maintains bone engaging portion  108  in a captive, telescopic relationship, the alignment of bone engaging portion  108  along axis L 2  is always maintained. Thus, when the procedure includes turning thread  122  through neck  12   b  of femur  12  and into head  12   c , head  12   c  will become fixed in an angular relationship relative to transverse member  102 . By maintaining the angular alignment between neck  12   b  and head  12   c , and allowing them to slide telescopically relative to one another, system  100  can accommodate for changes during patient movement and expedite the bone healing process. 
     After transverse member  102  is inserted, an opening is formed, preferably by drilling, into and generally along the medullary canal from a position slightly medial relative to the tip of the greater trochanter  12   a  and sized to receive nail  14  therethrough. Nail  14  is inserted through the longitudinal hole and into the medullary canal. Nail  14  passes through thru-hole  120  of connection portion  106 . Thru-hole  120  of transverse member  102  receives nail  14  in a close sliding fit, thereby permitting limited axial and rotational movement of transverse member  102  along axis L 1  of nail  14 . Transverse member  102  is longitudinally positioned on nail  14  so that passage  112  of connection portion  106  registers with opening  26  of nail  14 . If desired, bone engaging portion is further advanced into the bone at this stage. 
     Next, pin  103  is axially advanced through passage  112  by engaging hex recess  144  with an appropriate tool and rotating in a corresponding direction. As threaded portion  137  of pin  103  engages threaded portion  114  of connection portion  106 , leading portion  132  is slidably received within opening  26  to engage one or more surfaces  31   b ,  32   b . Even if passage  112  and opening  26  are misaligned, in many instances tapered tip  136  allows pin  103  to self-center, thereby aiding in the insertion of leading portion  132  within opening  26 . As pin  103  is slidably received within pathway  34  of opening  26  and guided along transverse axis T 2 , leading portion  132  forms an abutting relationship with one or both of angled surfaces  31   b ,  32   b . Pin  103  thus becomes oriented at angle α 2  relative to axis L 1 , aiding in the fixation of transverse member  102  relative to nail  14 . As pin  103  is further advanced through passage  112 , engaging surface  135  is firmly pressed against nail  14  and transverse member  102  is pulled in a proximal direction. Correspondingly, an inner surface of transverse member  102  that borders thru-hole  120  is clamped against an outer surface of nail  14  while generally maintaining angle α 2  of transverse member  102  relative to axis L 1 . 
     After securely clamping transverse member  102  and nail  14  together, generally parallel passages are formed, preferably by drilling through femur  12  transverse to the medullary canal and aligned with transverse bores  24   a ,  24   b  of nail  14 . Nail  14  is further locked into position by inserting locking bone screws  22   a ,  22   b  through femur  12  and into transverse bores  24   a ,  24   b  of nail  14 . 
     Referring to FIG. 9, system  160  of another embodiment of the present invention is illustrated; where reference numerals like those of previous embodiments refer to like features. System  160  includes transverse member  102 ′ which is the same as transverse member  102  except that pin  103 ′ is utilized in place of pin  103 . FIGS. 10A,  10 B,  11 A and  11 B illustrate selected details of pin  103 ′. Pin  103 ′ includes a leading portion  162  and a non-integral trailing portion  164 . Leading portion  162  preferably has a generally circular, elongated body and is sized to be received within opening  26  of nail  14 . Leading portion  162  also includes an angled, annular engaging surface  165  configured to co-act with a surface of nail  14 . Engaging surface  165  is aligned at an angle α 4  relative to axis L 4  of pin  103 ′. Leading portion  162  additionally includes a tapered tip  166 . 
     Leading portion  162  is articulated to trailing portion  164  to facilitate pivotal movement of portion  162  relative to portion  164 . Trailing portion  164  includes externally threaded portion  167  configured to threadedly engage threaded portion  114  of connection portion  106 . A hex recess  168  is defined by trailing portion  164  for receiving a driving tool (not shown), such as an Allen wrench, to advance pin  103 ′ axially along connection portion  106 . In other embodiments, pin  103 ′ is alternatively or additionally configured with a different means to be axially advanced through connection portion  106 , such as a ratcheting mechanism or a cabling arrangement. In still other embodiments, techniques are utilized as would occur to one skilled in the art. 
     Leading portion  162  has a longitudinal centerline axis L 4  and trailing portion  164  has a longitudinal centerline axis L 5 . Unlike pin  103 , leading portion  162  and trailing portion  164  are not integral and are coupled to permit leading portion  162  to pivot relative to trailing portion  164 . This pivoting or articulation permits angular variation of portion  162  relative to axis L 2 . In one preferred embodiment, leading portion  162  includes a ball and socket joint  170  to provide the angular adjustment capability. 
     The rear portion of leading portion  162  defines a concave surface  174  generally centered about axis L 4 . Projecting proximally from concave surface  174  along axis L 4  is stem  178 . Stem  178  has a generally circular cross section, but also preferably defines a pair of parallel, opposing flats  180   a ,  180   b . A ball member  182  is positioned at the end of stem  178  and is generally spherical-shaped. Trailing portion  164  defines a convex surface  184  generally centered about axis L 5  and configured to closely conform with concave surface  174  of leading portion  162 . Trailing portion  164  also defines a transverse socket  186  extending partially therethrough and aligned generally perpendicular to axis L 5 . 
     Transverse socket  186  has a diameter slightly larger than the diameter of ball member  182 . Transverse socket  186  terminates at concave bottom surface  188 . Concave bottom surface  188  substantially conforms with the outer surface of ball member  182 . Trailing portion  164  also defines a longitudinal bore  190  aligned with axis L 5 . Longitudinal bore  190  extends from convex surface  184  to transverse socket  186 . Longitudinal bore  190  is outwardly tapered with wide end  190   a  intersecting convex surface  184  and narrow end  190   b  intersecting transverse socket  186 , thus defining taper angle α 5  relative to axis L 5 . Preferably, taper angle α 5  is between about 5 degrees and 20 degrees. Most preferably, taper angle α 5  is about 10 degrees. Trailing portion  164  further defines a transverse slot  192  extending partially therethrough and substantially aligned with transverse socket  186 . Slot  192  has a width W extending along longitudinal bore  190  from convex surface  184  to transverse socket  186 . Slot  192  has a depth sufficient to intersect narrow end  190   b  of transverse bore  190 . Height H of slot  192  is slightly greater than the distance between flats  180   a ,  180   b  of stem  190 . Collectively, socket  186  and slot  192  are configured to receive ball member  182  and stem  178  therein, respectively. 
     In another embodiment of pin  103 ′, a flexible, readily deformable intermediate section is positioned between leading portion  162  and trailing portion  164  that may be additionally or alternatively used to provide means for allowing angular variation between axis L 4  and axis L 5 . In still another embodiment, portion  162  is journaled to portion  164  by a shaft through a bore, permitting rotation of portion  162  relative to portion  164 . In other embodiments, another suitable means for providing angular variation between axis L 4  and L 5  may alternatively or additionally be utilized as would occur to those skilled in the art. 
     As illustrated in FIG. 9, pin  103 ′ operates generally in the same manner as pin  103  described in connection with system  100 . Although pin  103 ′ can be used in instances where angles α 2  and α 3  are substantially equal (as shown in FIG.  9 ), the more preferred application arises in configurations where angles α 2  and α 3  are different. The articulation of leading portion  162  relative to trailing portion  164  facilitates secure clamping to nail  14  despite a mismatch between the angled surfaces  31   a ,  32   a , or  31   b ,  32   b  and the angular relationship of member  102 ′ to axis L 1  defined by thru-hole  120 . For example, referring additionally to FIG. 12, angles α 2  and α 3  are about 135 and 140 degrees, respectively, relative to axis L 1 . Preferably, the pivot range of leading portion  162  accommodates a range of different angular orientations of thru-hole  120  corresponding to α 3 . In one more preferred range, leading portion  162  pivots to accommodate a variation of angle α 3  from about 130 to about 145 degrees. 
     In one preferred implantation procedure, transverse member  102 ′ and nail  14  are implanted in accordance with the same procedure for inserting bone engaging member  108 , connection portion  106  and nail  14 , with the engagement of pin  103 ′ in place of pin  103 . For pin  103 ′, ball member  182  is inserted into socket  186  by aligning flats  180   a ,  180   b  of stem  178  with slot  192  and then guiding ball member  182  within transverse socket  186  until ball member  182  is positioned adjacent concave bottom surface  188 . A slight rotation or angulation of leading portion  162  relative to trailing portion  164  securely engages the two portions. As a result, leading portion  162  is rotatably coupled to trailing portion  164  by ball and socket joint  170 . Thus, leading portion  162  can rotate freely over a predetermined range within passage  112  as limited by taper angle α 5 . In one preferred embodiment, taper angle α 5  permits angular variation between leading portion  162  and trailing portion  164  of about 10 degrees in any direction. The assembly of leading portion  162  to trailing portion  164  may be performed during the implantation procedure just before insertion into passage  112  or in advance of the procedure as desired. 
     Once leading portion  162  and trailing portion  164  are assembled, Pin  103 ′ is advanced through passage  112  of connection portion  106  by engaging hex recess  168  and turning in the appropriate rotational direction. Pin  103 ′ is slidably received within pathway  34  of opening  26  and leading portion  162  is guided along transverse axis T 2  to form an abutting relationship with one or both of angled surfaces  31   b ,  32   b . If, as mentioned above, thru-hole  120  is disposed in connection portion  106  in correspondence to a different angle α 3  relative to axis L 1  (such as 140 degrees), leading portion  162  is forced to pivot relative to trailing portion  164  and thereby aligns at angle α 2  (such as 135 degrees). As trailing portion  164  is tightened in connection portion  106 , a rigid, secure construct forms between transverse member  102 ′ and nail  14  as described in connection with the operation of system  100 , except that pin  103 ′ may pivot, contacting an inner surface of connection portion  106  as illustrated in FIG.  12 . Notably, like system  10 , system  100  and  160  may be reconfigured to accommodate either the left or right femur or an antegrade or retrograde application; however, in other embodiments of the present invention, rod  14  may be modified to define only one generally linear pathway therethrough. 
     Referring now to FIG. 13, system  195  according to another embodiment of the present invention is illustrated; where reference numerals of previously described embodiments refer to like features. Preferably, system  195  is implanted in femur  12  as shown, and includes intramedullary rod or nail  14 , set screw  105 , and locking bone screws  22   a ,  22   b ,  22   c . In other embodiments, system  195  may be used in conjunction with other bones as would occur to one skilled in the art, such as the tibia, humerus, radius, ulna, or fibula to name a few. Additionally, the same components of system  195  can be used to treat either a left or right femur by simply rotating nail  14  180 degrees relative to longitudinal axis L 1 . Unlike systems  10 ,  100  and  160 ; system  195  positions nail  14  with the proximal and distal end portions reversed within femur  12  corresponding to implantation of nail  14  in a retrograde direction. Unlike existing systems, nail  14  need not be modified to operate in a retrograde direction. Indeed, nail  14  may be used in either an antegrade direction, as illustrated in connection with systems  10 ,  100 , and  160 , or a retrograde direction as illustrated in FIG.  13 . 
     One preferred implant procedure for system  195  includes forming a longitudinal hole along femur  12 , intersecting the medullary canal from a point generally central to distal end portion  12   d . The longitudinal hole is sized to receive nail  14  therethrough and is preferably formed by drilling into femur  12 . Nail  14  is inserted through the longitudinal hole and into the medullary canal. A pair of generally parallel, transverse passageways are formed, preferably by drilling, through femur  12  transverse to and intersecting with the medullary canal. These passageways are in registry with opening  26  and transverse bore  28 , respectively. Nail  14  is locked into position by inserting locking bone screws  22   a ,  22   b  into the transverse passageways and correspondingly through opening  26  and transverse bore  28 . Another transverse passageway is drilled through femur  12  across the medullary canal and intersecting therewith that is generally aligned with transverse bore  24   c  formed in distal portion  14   b  of nail  14 . Nail  14  is further locked into position by inserting locking bone screw  22   c  into this distal transverse passageway and correspondingly through transverse bore  24   c . Although system  195  does not require a sleeve to lock bone screws  22   a ,  22   b  into position relative to nail  14 , as discussed below, such a feature may optionally be utilized. 
     Referring now to FIG. 14, shown is bone treatment system  200  according to yet another embodiment of the present invention; where reference numerals of previously described embodiments refer to like features. System  200  is shown implanted in femur  12  and includes intramedullary nail  14 , sleeve  202 , bone engaging members  204 ,  205  and biasing sleeve  202 . Preferably, system  200  is utilized to treat fractures of the human femur, but may be used in conjunction with any other bone as would occur to those skilled in the art. Additionally, while system  200  can be used with any nail and sleeve configuration, it is preferably used in conjunction with retrograde implantation of nail  14  as described in connection with FIG. 13 herein. 
     In FIG. 14, opening  26  extends generally along transverse centerline axis T 3  and transverse bore  28  extends generally along transverse centerline axis T 4 . Opening  26  is bounded by a bearing surface  26   a  and bore  28  is bounded by a bearing surface  28   a . Sleeve  202  has a generally cylindrical shape and defines a proximal end  202   a , a distal end  202   b , and a side wall  208 . Sleeve  202  is sized to fit over proximal end portion  14   a  of nail  14 . Distal end  202   b  is therefore open to allow for passage of proximal end portion  14   a . Sleeve  202  defines an inwardly tapered edge  210 , terminating at distal end  202   b , to facilitate movement of sleeve  202  through bone. Proximal end  202   a  is also open to allow for the passage of nail insertion and extraction instrumentation (not shown). The interior surface of side wall  208  immediately adjacent proximal end  202   a  defines a threaded portion  211 . Side wall  208  also defines two sets of opposing apertures  212   a ,  212   b  and  214   a ,  214   b . Apertures  212   a ,  214   a  oppose apertures  212   b ,  214   b  in a direction along axes T 3 , T 4 , respectively. Aperture sets  212   a ,  212   b , and  214   a ,  214   b  are generally circular and are aligned and sized to respectively receive bone engaging members  204 ,  205  therethrough. Apertures  212   a ,  212   b  define circumferential engaging surfaces  213   a ,  213   b , respectively, and apertures  214   a ,  214   b  define circumferential engaging surfaces  215   a ,  215   b , respectively. 
     Bone engaging member  204  includes a proximal end portion  204   a  opposite a distal end portion  204   b . Bone engaging member  204  has a generally circular cross section and preferably has a diameter of about 5.5-6.5 millimeters for a femur application. Distal end portion  204   b  includes thread  216  for engaging and gripping bone. Alternatively or additionally, member  204  may include a different bone engaging or gripping means such as a bone blade having distal end portion  204   b  formed from a plate with a helical twist or an expansion device. Bone engaging member  205  includes a proximal end  205   a  and a distal end  205   b  and is preferably configured the same as bone engaging member  204 . 
     System  200  includes biasing end cap  220 . End cap  220  is generally circular and includes a first threaded portion  222  configured to threadingly engage threaded portion  211  of sleeve  202 . A second threaded portion  224  is configured to threadingly engage longitudinal bore  29  of nail  14 . End cap  220  proximally terminates in an enlarged, flat end portion  226  having protruding flange  228 . Flat end portion  226  also defines hex recess  230  for receiving a driving tool (not shown). 
     System  200  is utilized in accordance with one preferred femur implantation procedure by inserting nail  14  as described in connection with FIG. 13, except, proximal end  14   a  also carries sleeve  202  thereon by loosely threading end cap  220  into sleeve  202  and rod  14 . Accordingly, protruding flange  228  of flat end portion  226  bears against proximal end  202   a  of sleeve  202 . With sleeve  202  so oriented, apertures  212   a ,  212   b  are generally in alignment with transverse bore  28  along axis T 4  to define passageway  232 . Correspondingly, apertures  214   a ,  214   b  are generally aligned with opening  26  along transverse axis T 3  to defined passageway  234 . 
     Once the nail  14  and sleeve  202  are in place within femur  12 , two transverse passages are formed through the bone that are in registry with passageways  232 ,  234 . Next, bone engaging members  204 ,  205  are received through the bone and passageways  232 ,  234 , respectively. Once bone engaging members are in place. Sleeve  202  is biased by further tightening of end cap  220 . As end cap  220  is tightened, is moves sleeve  202  and nail  14  in opposite directions along axes L 1 . Correspondingly, surfaces  213   a ,  213   b  move to bear against bone engaging member  204  and engaging surfaces  214   a ,  214   b  bear against bone engaging member  205 . In turn, bone engaging member  204  is tightly clamped against bearing surface  26   a  of opening  26  and bone engaging member  205  is tightly clamped against bearing surface  28   a  of bore  28 . The tight engagement between bone engaging members  204 ,  205  and bearing surfaces  26   a ,  28   a  thereby clamps bone engaging members  204 ,  205  into position relative to nail  14  and prevents lateral migration. Locking nuts, which have in the past been used to prevent such lateral migration, are generally not needed for system  200 , so that additional surgical incisions normally required to engage locking nuts onto the bone engaging members need not be made and soft tissue irritation commonly associated with the presence of the locking nuts is also eliminated. Preparations and implantation of one or more bone engaging members may optionally be performed at distal end  14   b  of nail  14 . 
     In an alternative embodiment, end cap  220  does not include first threaded portion  222 . Thus, as threaded portion  224  engages longitudinal bore  29  of nail  14 , flange  228  of flat end portion  226  contacts proximal end  202   a  of sleeve  202  to advance sleeve  202  in a distal direction relative to nail  14 . In still another embodiment, end cap  220  does not include second threaded portion  224 . Thus, as threaded portion  222  engages threaded portion  211  of sleeve  202 , flat end  222   a  of threaded portion  222  is forced into contact with the proximal end of nail  14 , thereby advancing sleeve  202  in a proximal direction relative to nail  14 . In yet another embodiment of system  200 , the biasing means consists of a spring member operably captured between nail  14  and sleeve  202 . The spring member is configured to urge sleeve  202 , nail  14 , or both to clamp bone engaging members  204 ,  205 . 
     Referring now to FIG. 15, intramedullary system  300  according to still another embodiment of the present invention is illustrated; where reference numerals of previously described embodiments refer to like features. System  300  is shown implanted in femur  12  and includes elongated intramedullary nail  302 , positioning device  304 , bone engaging member  306  and locking bone screw  308 . Femur  12  includes a fracture site  301 , separating femur  12  into two portions  12   f ,  12   e . Fracture site  301  is shown in a compressed state (i.e., portions  12   f ,  12   e  are being pushed together). Although system  300  is shown implanted in femur  12 , system  300  could also be used in conjunction with other bones such as the tibia, humerus, radius, ulna and fibula to name a few. Additionally, the same components of system  300  can be used to treat either a left or right femur by simply rotating nail  302  180 degrees relative to axis L 6 . Although FIG. 15 illustrates nail  302  implanted within femur  12  in a retrograde direction, it is understood that system  300  could also be implanted with nail  302  in an antegrade direction. 
     FIGS. 15 and 16 show various structural details of nail  302 . It should be understood that nail  302  can take on a number of configurations, including that of nail  14  illustrated and described above. However, in a preferred embodiment, nail  302  is configured as described below. Nail  302  includes a proximal end portion  302   a  and a distal end portion  302   b . Nail  302  also defines a longitudinal axis L 6  running along the length of nail  302  between proximal end portion  302   a  and distal end portion  302   b . Proximal end portion  302   a  preferably has a diameter of about 11-12 millimeters for an adult human femur application. The diameter of the remainder of nail  302  can be varied depending upon the requirements of the fixation procedure and the surgeon&#39;s preference. While nail  302  has a generally circular cross section, other suitable shapes are also contemplated as would occur to one skilled in the art. 
     Nail  302  defines a passage  309  extending therethrough along axis L 6  line to allow for the optional use of a guide wire (not shown) to aid in the insertion of nail  302  in femur  12 . Distal end portion  302   b  defines parallel transverse bores  310   b ,  310   c , each sized to receive locking bone screw  308 . Distal end portion  302   b  also defines transverse bore  310   a , aligned generally perpendicular to transverse bores  310   b ,  310   c  and also sized to receive locking bone screw  308 . 
     Proximal end portion  302   a  defines an elongated, longitudinal opening  312  bounded by side walls  313  and sized to receive bone engaging member  306  therein. Opening  312  laterally extends through nail  302  and is elongated in the direction of longitudinal axis L 6 . Opening  312  has a first end portion  312   a  and an opposing second end portion  312   b . Proximal end portion  302   a  of nail  302  also defines a longitudinal passage  314  extending generally along axis L 6  and having a generally circular cross-section. Longitudinal passage  314  intersects opening  312  and terminates in a generally concave bottom surface  316 . A threaded portion  318  is defined about a portion of longitudinal passage  314 . Proximal end portion  302   a  also defines a transverse bore  320  extending through nail  302  generally perpendicular to axis L 6  and aligned with opening  312 . Bore  320  is sized to receive bone engaging member  306  therein. 
     Referring to FIG. 17, therein is shown nail  302 , positioning device  304  and bone engaging member  306  as assembled within system  300 . Positioning device  304  is shown positioned within longitudinal passage  314  and includes a first portion  322  and a second portion  324 . First portion  322  includes a head  326  and a threaded stem  328  extending therefrom generally along longitudinal axis L 6 . Head  326  is substantially circular and has an outer diameter generally corresponding to the outer diameter of nail  302 . Head  326  also includes a hex recess  330  for receiving a driving tool (not shown), such as an Allen wrench. The diameter of threaded stem  328  is less than the diameter of head  326 , thereby defining an annular shoulder  332 . 
     Second portion  324  defines a generally circular, elongated body  333  having a diameter slightly less than the diameter of longitudinal passage  314 . Second portion  324  also defines an internally threaded portion  334  extending generally along longitudinal axis L 6  and configured to threadedly engage threaded stem  328  of first portion  322 . Threaded portion  334  has a depth slightly greater than the length of threaded stem  328 . The end of second portion  324  opposite threaded portion  334  terminates into a generally convex outer surface  336  that substantially corresponds to concave bottom surface  316  of longitudinal passage  314 . Second portion  324  also defines a transverse opening  338  extending therethrough generally perpendicular to longitudinal axis L 6 . Opening  338  is bounded by inner surface  339  and is sized to receive bone engaging member  306  therein. 
     FIG. 17 illustrates a first operational position of system  300 . Positioning device  304  (including first and second portions  322 ,  324 ) is shown inserted within longitudinal passage  314  of nail  302 . Opening  338  of second portion  324  is positioned adjacent second end portion  312   b  of opening  312  and generally aligned with opening  312  to define a passageway  340 . Bone engaging member  306  is shown inserted through passageway  340 . Threaded stem  328  of first portion  322  is partially threadedly engaged within threaded portion  334  of second portion  324 . First portion  322  can be rotated by placing a driving tool (not shown) within hex recess  330  and turning in a clockwise or counterclockwise direction as appropriate. Second portion  324  is prevented from rotating in correspondence with first portion  322  because of engagement between bone engaging member  306  against sidewalls  313  of opening  312 . In one embodiment, threaded stem  328  and threaded portion  334  each have right-handed threads. In this embodiment, as first portion  322  is rotated in a clockwise direction, shoulder  332  of head  326  bears against nail  302 , and second portion  324  correspondingly moves toward first portion  322  generally along longitudinal axis L 6 . As the position of second portion  324  is adjusted along axis L 6 , inner surface  339  of opening  338  bears against bone engaging member  306  and correspondingly adjusts the position of bone engaging member  306  along the length of opening  312 . 
     FIG. 18 illustrates a second operational position of system  300  in which first portion  322  is rotated in a clockwise direction until bone engaging member  306  is positioned adjacent first end portion  312   a  of opening  312 . It should be understood, however, that bone engaging member  306  can be variably positioned anywhere along the length of opening  312 . It should further be understood that the terms “first operational position” and “second operational position” are not necessarily indicative of the initial position and adjusted position of bone engaging member  306 . For example, bone engaging member  306  could originate in a position adjacent first end portion  312   a  and be variably positioned anywhere along the length of opening  312 . 
     In other embodiments of system  300 , nail  302  defines a keyway extending along the length of longitudinal passage  314  generally parallel with axis L 6 . Additionally, second portion  324  defines a key along its length which generally corresponds to the keyway defined in nail  302 . Preferably, the key is radially positioned so that when it is slidably received within the keyway, opening  338  of second portion  324  will correspondingly align with opening  312  of nail  302 . Alternatively, the key could be defined along the length of second portion  324  and, correspondingly, the keyway could be defined along the length of longitudinal passage  314  of nail  302 . 
     Having described selected structural and operational features of nail  302  and positioning device  304 , the operational characteristics of system  300  will now be described in further detail. Referring back to FIG. 15, nail  302  is shown implanted in femur  12 . Distal end  302   b  of nail  302  is anchored to portion  12   e  of femur  12  by inserting locking bone screw  308  into portion  12   e  and through transverse bore  310   a  (not shown) of nail  302 . Proximal end  302   a  of nail  302  is anchored to portion  12   f  of femur  12  by inserting bone engaging member  306  into portion  12   f  and through passageway  340  (defined by aligning opening  338  with opening  312 ). Preferably, bone engaging member  306  is initially positioned adjacent or near second end portion  312   b  of opening  312 . As first portion  322  of positioning device  304  is rotated in a clockwise direction, bone engaging member  306  is correspondingly repositioned along the length of opening  312 , and more specifically is transferred toward first end portion  312   a . Because bone engaging member  306  is anchored to portion  12   f  of femur  12 , portion  12   f  is correspondingly moved in the direction of arrow “A”, while portion  12   e  of femur  12  remains stationery, securely anchored to distal end  302   b  of nail  302 . Thus, portion  12   f  of femur  12  is repositioned away from portion  12   e , thereby distracting fracture site  301 . 
     One preferred procedure for implanting system  300  within femur  12  includes forming a longitudinal hole along the medullary canal from a point generally central to the distal end portion  12   d  of femur  12 . Preferably this hole is formed by drilling sized to receive nail  302  therethrough. Positioning device  304  is inserted in longitudinal passage  314  of nail  302  and nail  302  is inserted through the longitudinal hole and into the medullary canal. It should be understood that positioning device  304  could alternatively be inserted in longitudinal passage  314  after nail  302  has been implanted in femur  12 . A first passage is formed through femur  12  transverse to the medullary canal and generally aligned with transverse bore  310   a  (not shown) formed in distal portion  302   b  of nail  302 . A second passage is formed through femur  12  transverse to the medullary canal and generally aligned with passageway  340 . Preferably, these transverse passages are formed by drilling. Locking bone screw  308  is threaded into the first passage, passing through transverse bore  310   a . Bone engaging member  306  is threaded into the second passage, passing through passageway  340 . At this point, fracture site  301  can be distracted by following the operational procedure described above. Dashed line  301   a  of FIG. 15 corresponds to the position of the fractured end of portion  12   f  after distraction in accordance with one embodiment of the present invention. 
     Referring now to FIG. 19, intramedullary system  400  according to yet another embodiment of the present invention is illustrated; where like reference numerals of previously described embodiments refer to like features. System  400  is shown implanted in femur  12  and includes elongated intramedullary nail  302 , positioning device  304 ′, bone engaging member  306  and locking bone screw  308 . Femur  12  includes a fracture site  301 ′, separating femur  12  into two portions  12   f ,  12   e . Fracture site  301 ′ is shown in a distracted state (i.e., portion  12   a ,  12   b  are spaced apart relative to one another). Although system  400  is shown implanted in femur  12 , system  400  could also be used in conjunction with other bones as would occur to one skilled in the art, including the tibia, humerus, radius, ulna and fibula, to name a few. Additionally, the same components of system  400  can be used to treat either a left or right femur by simply rotating nail  302  180 degrees relative to axis L 6 . Although FIG.  19  illustrates nail  302  implanted within femur  12  in a retrograde direction, it is understood system  400  may also be implanted with nail  302  in an antegrade direction. 
     Referring to FIG. 20, therein is shown nail  302 , positioning member  304 ′ and bone engaging member  306  as assembled within system  400 . Positioning member  304 ′ is shown positioned within longitudinal passage  314  and includes a first portion  402  and a second portion  404 . First portion  402  includes a threaded upper portion  406  and an elongated lower portion  408  extending therefrom along longitudinal axis L 6 . Upper portion  406  is configured to threadedly engage threaded portion  318  of longitudinal passage  314 . Upper portion  406  also includes a hex recess  410  for receiving a driving tool (not shown), such as an Allen wrench. Lower portion  408  has a generally circular body having an outer diameter slightly less than the diameter of longitudinal passage  314 . A transverse passage  412  extends through lower portion  408  and is aligned generally perpendicular to axis L 6 . The end of lower portion  408  opposite its threaded portion terminates in a generally flat surface  414 . 
     Second portion  404  has a circular body having an outer diameter generally corresponding to the outer diameter of lower portion  408  of first portion  402 . Second portion  404  defines an internally threaded portion  416  extending generally along axis L 6  for engaging insertion instrumentation (not shown). One end of second portion  404  defines a generally flat surface  418 , corresponding to surface  414  of lower portion  408 . The opposing end of second portion  404  terminates in a generally convex outer surface  420  substantially corresponding to concave bottom surface  316  of longitudinal passage  314 . Second portion  404  also defines a transverse opening  422  extending therethrough generally perpendicular to axis L 6 . Opening  422  is bound by inner surface  424  and is sized to receive bone engaging member  306  therein. 
     FIG. 20 illustrates a first operational position of system  400 . Positioning device  304 ′ (including first and second portions  402 ,  404 ) is shown inserted within longitudinal passage  314  of nail  302 . Opening  422  of second portion  404  is positioned adjacent first end portion  312   a  of opening  312  and generally aligned with opening  312  to define a passageway  426 . Bone engaging member  306  is shown inserted through passageway  426 . Upper portion  406  of first portion  402  is partially threadedly engaged within threaded portion  318  of longitudinal passage  314 . First portion  402  can be rotated by placing a driving tool (not shown) within hex recess  410  and turning first portion  402  in a clockwise or counterclockwise direction. In one embodiment, threaded upper portion  406  and threaded portion  318  each have right-handed threads. In this embodiment, as first portion  402  is rotated in a clockwise direction, it will be advanced through longitudinal passage  314  generally along axis L 6 . As first portion  402  is advanced, surface  414  will engage surface  418  of second portion  404 , thereby correspondingly advancing second portion  404  through longitudinal passage  314  generally along axis L 6 . As the position of second portion  404  is adjusted along axis L 6 , inner surface  424  of opening  422  bears against bone engaging member  306  and correspondingly adjusts the position of bone engaging member  306  along the length of opening  312 . 
     FIG. 21 illustrates a second operational position of system  400  in which first portion  402  is rotated in a clockwise direction until bone engaging member  306  is positioned adjacent second end portion  312   b  of opening  312 . It should be understood, however, that bone engaging member  306  can be variably positioned anywhere along the length of opening  312 . It should further be understood that the terms “first operational position” and “second operational position” are not necessarily indicative of the initial position and adjusted position of bone engaging member  306 . For example, bone engaging member  306  could originate in a position adjacent second end portion  312   b  and be variably positioned anywhere along the length of opening  312 . 
     When bone engaging member  306  is positioned adjacent second end portion  312   b  of opening  312 , transverse passage  412  of upper portion  406  will become aligned with transverse bore  320  of nail  302 , thereby defining a passageway  430 . A second bone engaging member  306  can then be inserted through passageway  430  to prevent further rotational movement of first portion  402  relative to nail  302 . However, if transverse passage  412  and transverse bore  320  cannot be aligned to form passageway  430 , a second bone engaging member  306  cannot be used. In this case, in order to prevent first portion  402  from rotating and migrating relative to nail  302 , a locking set screw can be threadedly advanced along threaded portion  318  of nail  302  until it tightly engages upper portion  406 . 
     Having described selected structural and operational features of positioning device  304 ′, the operational characteristics of system  400  will now be described in further detail. Referring back to FIG. 19, nail  302  is shown implanted in femur  12  and is anchored to portions  12   a  and  12   b  in substantially the same manner as described above in system  300 . Preferably, bone engaging member  306  is initially positioned adjacent or near first end portion  312   a  of opening  312 . As first portion  402  of positioning device  304 ′ is rotated in a clockwise direction, bone engaging member  306  is correspondingly repositioned along the length of opening  312 , and more specifically is transferred toward second end portion  312   b  of opening  312 . Because bone engaging member  306  is anchored to portion  12   f  of femur  12 , portion  12   f  is correspondingly moved in the direction of arrow “B”, while portion  12   e  of femur  12  remains stationary, securely anchored to distal end  302   b  of nail  302 . Thus, portion  12   f  of femur  12  is repositioned toward portion  12   e , thereby compressing fracture site  301 ′. Dashed line  301   b  of FIG. 19 corresponds to the fractured end of portion  12   f  after compression in accordance with one embodiment of the present invention. 
     One preferred procedure for implanting system  400  within femur  12  is substantially identical to the procedure for implanting system  300 , except a compression operation as described above is performed instead of the distraction operation as described in connection with system  300 . 
     The components of systems  10 ,  100 ,  165 ,  195 ,  200 ,  300  and  400  maybe fabricated from any suitably strong, bio-compatible material such as stainless steel, titanium, chrome-cobalt, or any other material which would occur to those skilled in the art. 
     While the invention has been illustrated and described in detail in the drawings and foregoing discussion, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.