fig1 - 3 depict the surgical drill in accordance with the present invention , which comprises drill guide 20 , pin 60 , and flexible drill 70 . the surgical drill of the present invention provides a second hole along an axis y that may be at an angle relative to a first hole along an axis x . more specifically , particularly in view of the problems associated with the prior art described herein , the surgeon can drill a tunnel in the femur at an angle relative to a tunnel in the tibia . because the surgeon can access the femur via the tunnel in the tibia , the surgical drill of the present invention obviates the need for a second hole in the tissue and also makes placement of femoral tunnel 90 more precise for securement of the ligament or tendon graft within the tunnel . as discussed in the prior art , placement of the femoral tunnel was problematic and poor placement may lead to improperly secured ligaments or tendons . referencing fig1 , drill guide 20 of the surgical drill comprises a head 22 , rotatably connected to a body 24 , an actuator assembly 26 , a handle 28 , and an internal longitudinal channel 30 having an opening 32 for releasably accepting guide pin 60 . the channel 30 extends through the body 24 and into the head 22 . as shown in more detail in fig5 , actuator assembly 26 comprises a rod 34 having a distal end 36 and a proximal end 38 , a screw 40 having external threads 42 , and a knob 44 threadably connected to the screw 40 . the distal end 36 of the rod 34 is connected to the head and the proximal end 38 is connected to the screw 40 . the actuator assembly is contained within a housing 46 . to adjust the angle a of head 22 relative to body 24 , a user rotates knob 44 . due to their threaded connection , this rotation of the knob 44 translates into linear movement of screw 40 and rod 38 . to provide rotation of the head 22 with actuation of the rod 40 , the rod is connected to the head at a point radially spaced apart from the pivot point 48 where the head 22 connects to the body 24 . in the present embodiment , clockwise rotation of the knob 44 causes the rod 38 to advance towards the distal end 36 , which causes the head 22 to accordingly rotate clockwise . counter - clockwise rotation of the knob 44 causes the rod 38 to retract towards the proximal end 38 , which , in turn , causes the head to rotate counter - clockwise . in a preferred embodiment , the ratio of rotation of the knob to angular rotation of the head is 18 : 1 , meaning that for every 18 degrees of rotation of knob 44 , angle a will change by 1 degree . thus , to adjust angle a by 15 degrees , the knob 44 must be rotated by 270 degrees . this ratio provides the user with acceptable precision for adjustment of angle a , yet allows full range of motion of the head with only one turning motion . other ratios are contemplated herein and could be easily adjusted by one having skill in the art . in addition , other mechanisms , such as a trigger , are contemplated for adjusting the angular orientation of the head 22 with respect to the body 24 . guide pin 60 of the surgical drill , depicted in fig2 , has a distal end 62 and a proximal end 64 . pin head 66 , located at the distal end 62 , is pointed in the present embodiment so that it may penetrate a patient &# 39 ; s femur bone . in an alternative embodiment , distal end 62 may be formed as a screw so that it may be screwed into a patient &# 39 ; s femur bone . as shown in fig6 ( a ) and 6 ( b ), angular adjustment of head 22 causes an angular displacement a of pin 60 with respect to the body 24 . thus , guide pin 60 is made of a flexible material such that it can bend when the angle a of the head 22 of the drill guide 20 is adjusted . however , the material must be rigid enough so that it will maintain its shape when the drill 70 is passed over the guide pin 60 . drill 70 of the surgical drill , depicted in fig3 , has a distal end 72 and a proximal end 74 . located at the distal end 72 is the drill bit 76 and flexible portion 78 . an internal channel 80 that runs the length of the drill 70 is also provided so that the drill 70 may be slid over the guide pin 60 . flexible portion 78 allows the drill 70 to pass over the guide pin 60 in a bent shape . in operation , known methods are used to create a tibial tunnel 80 in the tibia 82 that extends towards the femur 84 . typically , a drill guide specifically designed for drilling tibial tunnels is placed against the tissue . a guide pin is then inserted into the drill guide for piercing the tissue to create a first tissue hole . once the guide pin is anchored in the tibia , the drill guide is removed and a standard drill is slid over the drill guide and is used to create tibial tunnel 80 . referring now to fig7 and 8 , to create a femoral tunnel 90 , guide pin 60 is inserted into opening 32 of drill guide 20 . together , the drill guide 20 and guide pin 60 are inserted into the tibial tunnel 80 until the guide 20 is in close proximity to the femur and the head 22 has passed through tibial tunnel 80 . the user , typically a surgeon , then rotates knob 44 to adjust the angle a of head 22 . because the body 24 of the drill guide 20 remains stationary within the tibial tunnel 80 while the head 22 is free to rotate with respect to the body 24 , the drill guide of the present invention allows the user to drill a second ( femur ) tunnel at an angle to the first ( tibia ) tunnel . once a desired angle is achieved , pin 60 is pushed further through the internal channel 30 until pin head 66 passes through the now angled head 22 and in comes in contact with femur 84 . once in contact with femur 84 , further force is needed to anchor pin head 66 within femur 84 . in some cases , this further force is achieved by drilling the pin through drill guide 20 . notably , the drill guide of the present invention is versatile in that it provides a surgeon with a large range of angles at which to place the femoral tunnel with respect to the tibial tunnel . thus , the surgeon is not limited to either drilling a straight femoral tunnel or to drilling the femoral tunnel at a single , fixed angle , as is the case with the straight or fixed angle drill guides of the prior art . drill guide 20 is then removed by sliding it away from the femur 84 back through the tibial tunnel 80 and away from the patient . as shown in fig9 , guide pin 60 is left in place anchored to femur 84 . flexible drill 70 is then inserted around pin 60 toward the patient by passing pin 60 through internal channel 80 of flexible drill 70 . the diameter of flexible drill 70 should be the same as or smaller than the diameter of tibia hole 80 such that flexible drill 70 passes through tibia hole 80 and toward femur 84 . it should be understood that pin 60 acts as a guide for leading flexible drill 70 toward femur 84 at the angle set by pin 60 and head 22 . once in contact with femur 84 , flexible drill 70 drills femoral tunnel 90 by being rotated about with a standard driller , or machine for rotating a drill bit . after femoral tunnel 90 is drilled , flexible drill 70 and guide pin 60 are removed from the patient . as shown in fig1 , resulting is a femoral tunnel placed at an angle with respect to the tibial tunnel . in another embodiment , flexible pin 60 and flexible drill 70 are used to drill both tibial tunnel 80 and femoral tunnel 90 . this is accomplished by pin 60 first being anchored in tibia 82 , at which point the tibia drill guide is removed from pin 60 as described above . flexible drill 70 is then slid over pin 60 , but this time to simply create a straight tunnel , or a tunnel being straight relative to body 24 . since tibia hole 80 is straight , either a straight drill ( not shown ) standard in the industry or prior art , or flexible drill 70 may be used . once tibial tunnel 80 is created , flexible drill 70 is removed and the drill guide 20 is inserted in order to locate femur hole 90 at an angle relative to tibia hole 80 . the above description for placing femur hole 90 is then followed . it should be understood that the foregoing is illustrative and not limiting , and that obvious modifications may be made by those skilled in the art without departing from the spirit of the invention . accordingly , reference should be made primarily to the accompanying claims , rather than the foregoing specification , to determine the scope of the invention .
a surgical drill for providing holes at an angle for use in repair and replacement of the acl is disclosed , generally comprising a drill guide having a head that is angularly adjustable with respect to a body , a flexible guide pin and a flexible drill . the adjustable head of the drill guide allows a surgeon to drill a hole in the femur at an angle to a tunnel provided in the tibia . because the surgeon can access the femur via the hole in the tibia , the surgical drill of the present invention obviates the need for a second hole in the tissue and also makes placement of femur hole more precise for securement of the ligament or tendon graft within the hole .