as shown in fig1 , the femoral distractor unit 10 includes a knee support bar 11 at one end for supporting a patient &# 39 ; s knee during surgery and a base support bar 12 at the opposite end for attaching to a support base 13 , similar to that described within u . s . pat . no . 7 , 003 , 827 entitled “ operating table support clamp ”, which patent is incorporated herein for purposes of reference . an outer cylinder 19 interconnects between the support bar 11 and support base 13 via the support bar 12 at one end and the u - shaped support 21 at the opposite end thereof . the support bar 12 is attached to the support base 13 via connector pin 15 in press - fit relation to allow the unit 10 to move along the knee positioner carriage rail ( not shown ) via the extended slot 14 . although the unit 10 is arranged herein for attachment to the knee positioner , device , per se , as described in the aforementioned u . s . pat . no . 7 , 003 , 827 , for example , it is to be understood that the unit could be directly attached to an operating table side rail , via a modified clamp ( not shown .) the driver rod 18 extends within the outer cylinder 19 and is attached to the support bar 11 , via screw 17 to move the support bar 11 in the indicated vertical direction against the bias of the compression spring 9 arranged within the u - shaped support 21 . a sterile foam cylinder 27 is arranged on the support bar 11 to insure sterile contact with the patient &# 39 ; s knee ( not shown ). the lever 26 , arranged on the driver rod 18 in press - fit relation , extends , at one end , under the lever pin 25 . the handle lever 22 is pivotally attached to the flange 23 extending from the u - shaped support 21 via pivot pin 24 . when the handle lever 22 is moved toward the outer cylinder 19 , lever pin 25 drives the spring lever 26 and the attached driver rod 18 in the vertical direction against the bias of the compression spring 9 to thereby move the attached support bar 11 in the vertical direction . the relative movement of the handle lever 22 towards the outer cylinder 19 governs the associated movement of the driver rod and attached support bar 11 in a controlled manner . maintaining the handle lever 22 in a determined position relative to the outer cylinder 19 holds the support bar in an associated determined position , during knee surgery , which is an important feature of the instant invention . when the patient &# 39 ; s knee ( not shown ) is arranged over the support bar 11 and the knee is incised to separate the femur and tibia , movement of the handle lever 22 controls the position of the knee and accordingly determines the precise distance that the femur is separated from the tibia , during the course of the knee surgery . to move the femur toward the tibia , tension on the handle lever 22 is controllably released to allow the compression spring 9 to force the driver rod 18 and attached support bar 11 to thereby move the femur in the opposite vertical direction . the arrangement of the components within the femoral distractor unit 10 is best seen by now referring to fig2 . the outer cylinder 19 having the support bar 12 welded at the end , receives the connector pin 15 for attachment to a knee positioner , as described earlier , along with a threaded opening 19 b for allowing the attachment of the outer cylinder 19 to a surgical knee positioner unit ( not shown ) via threaded bolt 16 . the u - shaped support 21 is welded at the opposite end of the outer cylinder 19 and receives the driver spring 9 and release spring lever 26 , which includes an opening 26 a for receiving the driver rod 18 in press - fit relation . the handle lever 22 includes apertures 22 a , for attachment to the u - shaped support 21 via aperture 28 and pivot pin 24 along with apertures 22 b for receiving lever pin 25 that is positioned under one end 26 b of the spring lever 26 for the purposes described earlier with reference to fig1 . the driver rod 18 extends thru aperture 11 a , at one end of the support bar 11 , for attachment to the support bar via screw 17 . prior to surgery , the sterile foam cylinder 27 is positioned over the support bar 11 to provide sterile contact with the patient &# 39 ; s knee ( not shown ). a simple and efficient arrangement has been described herein whereby a patient &# 39 ; s femur can be precisely separated from the tibia during knee surgery without requiring insertions of pins , rods , spreaders and the like into the femur / tibia space or medullar canal as often required with prior knee surgery operations .
a femoral distractor includes a top post for positioning under a patient &# 39 ; s knee and a bottom pin for fixed attachment to a hospital bed rail . a vertical rod extends between the top post and horizontal bottom pin to move the knee joint in the vertical direction upon operation of a trigger assembly .