Method and apparatus for tibial resection

A method an apparatus for resecting a proximal tibia during a knee replacement operation is provided. The apparatus includes an ankle clamp, an alignment rod, a fixation head, cutting guide clamps having cutting guide slots therein, and a milling bit. The method includes the steps of attaching the ankle clamp about the ankle, interconnecting the distal end of the alignment rod with the ankle clamp, interconnecting the fixation head with the proximal end of the alignment rod, partially attaching the fixation head to the proximal tibia, aligning the alignment rod, completely attaching the fixation head to the proximal tibia, interconnecting the cutting guide clamps with the alignment rod, positioning the cutting guide clamps about the proximal tibia, securing the cutting guide clamps to the tibia at a proper location, removing the fixation head, placing the milling bit within the cutting guide slots, and cutting the proximal tibia with the milling bit.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention generally relates to a method and apparatus for resecting a 
proximal human tibia to allow it to properly accept a proximal tibial 
prosthesis in the context of a total knee replacement operation. 
2. Related Art 
In the past, efforts have been made to develop methods and apparatus to 
resect the proximal human tibia in the context of knee replacement 
surgery. Many of these previous efforts, as shown in the previous relevant 
patents, align the tibia resection off of the intermedullary canal of the 
tibia, while others base alignment off of exterior alignment rods. These 
previous efforts also include alignment adjustment mechanisms, though 
these mechanisms tend to be complicated and generally inaccurate. None of 
the methods or apparatus that have been developed can consistently and 
accurately locate and properly align the tibia resection, while minimizing 
the cutting skill necessary to properly and safely resect the tibia, as 
well as smoothly cutting the tibia. Nor do any of the previous efforts 
disclose a simple but effective method and apparatus for efficiently 
resecting the proximal tibia. These past efforts include: 
Stillwell, U.S. Pat. No. 4,457,307, which discloses a movable saw and saw 
carriage which may be mounted to the femur for resecting the femur. The 
saw and saw carriage are adjustable through a plurality of positions to 
make desired cuts in the femur. Additionally, the device may be used to 
cut the proximal tibia. First, the knee is extended, the collateral 
ligaments are tensioned and balanced, and the proximal tibia cortex is 
scored. Then, the knee is flexed, the saw and saw carriage readjusted, and 
the tibia cortex cut is completed. 
Androphy, U.S. Pat. No. 4,487,203, discloses a knee resection system 
comprising a guide member, femur and tibia guide rods, a tibia adaptor, a 
tibia bar, and a femur bar. After the distal femoral condyles are 
resected, the guide member is attached to the tibia guide rod extending 
into the tibia. The tibia guide rod has a second guide at a right angle 
for receiving the guide member. When properly aligned, the guide member is 
fixed to the anterior side of the proximal tibia with pins. The tibia is 
then resected with an oscillating saw inserted through slots in the guide 
member. 
Rohr, Jr., U.S. Pat. No. 4,566,488, discloses a ligament tensor device 
having a first member to engage the tibia and a second member to engage 
the intercondylar notch of the femur. This device includes means for 
moving the first member with respect to the second member for applying a 
selected tension to the ligaments of the knee joint. The device includes a 
tibia cutting guide which supports a tibia cutting guide head which is 
positioned and angled to guide the cutting of the tibial plateau. The 
cutting guide head includes a transverse cutting guide slot. An ankle 
guide bracket is attached to the lower end of the tibia cutting guide and 
attaches to the tibia at the ankle for supporting and aligning the tibia 
cutting guide structure. 
Kenna, U.S. Pat. Nos. 4,653,488 and 4,787,383, disclose a tibial cutting 
jig for cutting a tibia after the femur has been resected. The tibia is 
aligned off of the resected femur through longitudinal traction and 
manipulation to bring the ankle under the femur to produce a tibial angle 
of 2.5 degrees resulting in an overall valgus alignment. The alignment is 
verified by sight. The knee joint is then immobilized, the transverse 
tibial cutting jig is pinned to the tibia, the knee is moved to flexion, 
and the tibia is cut by resting the saw blade on the top surface of the 
cutting jig. 
Russell, et al., U.S. Pat. No. 4,722,330, discloses a distal femoral 
surface guide for mounting on an intermedullary alignment guide for use in 
shaping the distal femoral surface. A conventional shaping means such as 
an oscillating saw or hand saw is introduced into slots in the surface 
guide to resect the femur. The device also includes stabilizing members 
that extend along the sides of the femur to stabilize the device. 
Fargie, et al., U.S. Pat. No. 4,736,737 discloses a tibial cutting jig 
having a base that interconnects with an intermedullary alignment rod 
installed along the axis of the tibia. The base includes outriggers 
carrying measurement keys for spacing the base a preselected distance 
above the tibia. A saw guide having slots is attached to the base and is 
positioned to allow for the cutting of the tibia, by means of an 
oscillating saw, at a selected position. 
Whiteside, et al., U.S. Pat. No. 5,002,545, discloses a shaping device for 
shaping the tibial plateau comprising an alignment rod located anterior to 
the anterior cruciate ligament and along the anterior cortex of the 
intermedullary canal of the tibia. The shaping guide is interconnected 
with the rod and is adjustable with respect to the rod to control the 
amount of resection of the tibial plateau by raising or lowering the 
cutting guide surfaces. The device includes a pin which is inserted into a 
hole on the alignment guide for setting rotation alignment by aligning the 
pin with the intercondylar notch of the femur. 
Poggie, et al., U.S. Pat. No. 5,250,050 discloses an apparatus for use in 
preparing the bone surfaces for a total knee prothesis, comprising cutting 
guides, templates, alignment guides, a distractor and clamping 
instruments. The instrument for alignment of the cutting surface for 
resecting the tibia includes an ankle clamp, an adjustable alignment rod, 
and a cutting platform. After the cutting platform is properly aligned on 
the tibia, it is pinned thereto and the tibia may be resected using an 
oscillating saw. Also disclosed is a patella resection guide comprising a 
scissor-type clamp having distal gripping arms, each of which define a 
cutting surface, and gripping teeth. 
Caspari, et al., U.S. Pat. Nos. 5,263,498, 5,228,459, and 5,304,181 
disclose a method and apparatus for orthoscopically preparing bone 
surfaces for a knee replacement. A tibial jig is attached to the tibia at 
just above the ankle at a lower end and to just below the tibial tubercle 
at an upper end. One portal is formed in the knee for insertion of an 
orthoscope for viewing the knee, and another portal is formed for 
introducing resecting instruments. A cutting platform is aligned and 
secured in position and a cutting module is attached. Initially, a plunge 
cut across the tibial eminence is produced. This procedure is repeated 
until the surface of the tibial plateau is covered with trails having 
ridges therebetween. Thereafter, the device is passed back and forth over 
the tibial plateau to remove the ridges. 
Morgan, U.S. Pat. No. 5,269,786, discloses a PCL oriented placement tibial 
guide method for guiding the tibial tunnel placement both inside and 
outside the knee in endoscopic ACL reconstruction. 
Mikhail, U.S. Pat. No. 5,284,842, discloses a universal patellar clamp 
having an articular surface clamping member with a central aperture 
defining a centerline axis. An anterior clamping member is positioned 
along the centerline axis and is movable with respect to the articular 
clamping member to effect clamping of the patella for accepting a reamer 
for reaming a cavity in the patella of sufficient size to receive a 
patellar implant. 
Johnson et al., U.S. Pat. No. 5,306,276, discloses a tibial resector guide 
including a tibial alignment jig having an ankle adjustment mechanism, a 
telescoping rod and a tibial resector guide which includes a head having a 
slot for receiving a bone saw. The head includes angled side walls along 
the slot which permit the guide to have a narrow anterior aperture, yet 
allow the saw blade to completely pass through the tibia. 
Peterson, U.S. Pat. No. 5,342,368, discloses an intermedullary tibial 
resector guide which is affixed to the tibia by means of an intermedullary 
rod. An elongated bar extends from the intermedullary rod and carries a 
sleeve that supports a saw guide having a slot for receiving an 
oscillating saw. 
Whitlock, et al., U.S. Pat. No. 5,147,365, discloses a patella osteotomy 
guide comprising a plier-like appliance with curved jaws for grasping a 
patella. A row of teeth face inwardly from the jaws and a rotating 
calibrated stylus measures the position of the patella with respect to an 
integral saw capture slot in each of the jaws. The jaws are curved with 
concave inner sides generally corresponding to the shape of a patella. 
With the guide attached to a patella, a sagittal saw can be passed through 
the saw capture slots to cut away a portion of the patella. 
None of these previous efforts are as simple and easy to use as the present 
invention. Additionally, none of these previous efforts disclose all of 
the benefits and advantages of the present invention, nor do they teach or 
suggest all of the elements of the present invention. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is a primary object of the present invention to provide a method and 
apparatus for properly resecting the proximal human tibia in connection 
with knee replacement surgery. 
It is also an object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which minimizes the skill 
necessary to complete the procedure. 
It is another object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which properly orients 
the resection of the proximal tibia. 
It is even another object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which is easy to use. 
It is yet another object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which orients the 
resection in accordance with what is desired in the art. 
It is still yet another object of the present invention to provide a method 
and apparatus for resecting the proximal human tibia which minimizes the 
amount of bone cut. 
It is a further object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which allows one to 
visually inspect the location of the cut prior to making the cut. 
It is even a further object of the present invention to provide a method 
and apparatus for resecting the proximal human tibia which is simple in 
design and precise and accurate in operation. 
It is yet a further object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which physically removes 
material from the proximal tibia along a surface dictated by a guide 
device. 
It is still a further object of the present invention to provide a method 
and apparatus for resecting the proximal human tibia which employs a 
milling bit for removing material from the proximal tibia. 
It is also object of the present invention to provide a method and 
apparatus for resecting the proximal human tibia which includes a 
component which is operated, and looks and functions, like pliers or 
clamps. 
It is even another object of the present invention to provide an alternate 
embodiment of the method and apparatus for resecting the proximal human 
tibia which includes a component that resembles a U-shaped device for 
placing about the tibia. 
It is even a further object of the present invention to provide an 
alternate embodiment of the method and apparatus for resecting the 
proximal human tibia which includes a component that resembles an 
adjustable, square, U-shaped device for placing about the tibia. 
These objects and others are met and accomplished by the method and 
apparatus of the present invention for resecting the proximal tibia. 
The apparatus of the present invention comprises a number of components 
including an ankle clamp, an alignment rod, a fixation head, cutting guide 
clamps having an integral attachment mechanism, and a milling bit. 
The method of present invention includes the steps of attaching the ankle 
clamp about the ankle, interconnecting the distal end of the alignment rod 
with the ankle clamp, interconnecting the fixation head with the proximal 
end of the alignment rod, partially attaching the fixation head to the 
proximal tibia, aligning the alignment rod, completely attaching the 
fixation head to the proximal tibia, interconnecting the cutting guide 
clamps with the alignment rod, positioning the cutting guide clamps about 
the proximal tibia, securing the cutting guide clamps to the tibia at a 
proper location, removing the fixation head, and cutting the proximal 
tibia with the milling bit.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in FIGS. 1-6, the tibial resection apparatus of the present 
invention includes a number of components, namely, cutting guide clamps 
generally indicated at 10, cutting guides generally indicated at 20, ankle 
clamp generally indicated at 50, alignment rod generally indicated at 60, 
cutting guide clamp linkage generally indicated at 70, fixation block 
generally indicated at 80, proximal tibial referencing stylus generally 
indicated at 90, and milling bit generally indicated at 55. It should be 
noted that the cutting guides 20 may be formed integrally with the cutting 
guide clamps 10 as shown in FIGS. 1 and 2, or a separate members as shown 
in FIGS. 4, 5 and 6. Also, the cutting guides 20 may ride the alignment 60 
as shown in FIGS. 1 and 2, or they may interconnect with the alignment rod 
60 by means of cutting guide clamp linkage 70 as shown in FIGS. 4, 5 and 
6. 
As shown in FIG. 1, the ankle clamp 50 is attached at or just above the 
ankle and exterior to the skin. Any conventional ankle clamp may be used 
to firmly engage the ankle, or to engage the tibia above the ankle, to 
obtain a reference point for the other components of the present 
invention. 
The ankle clamp is interconnected with and locked into place on the 
alignment rod 60 in any way known in the art. Preferably, though not 
necessarily, the alignment rod 60 is vertically adjustable with respect to 
the ankle clamp 50. This vertical adjustment can be achieved at the ankle 
clamp 50, at the interconnection of the ankle clamp 50 and the alignment 
rod 60, or within the alignment rod 60 itself. As shown in FIG. 1, the 
alignment rod includes a first lower end 62 having an aperture 63 
extending vertically therein for telescopically receiving a second upper 
end 65 of the alignment rod 60. A set screw 64 is provided for fixing the 
upper end 65 with respect to the lower end 62. 
The fixation block 80 is interconnected with an upper end of the alignment 
rod 60 by means of an aperture 82 in the fixation block 80 sized to 
receive the alignment rod 60 therethrough, or in any other manner known in 
the art. A set screw 84 may be provided to extend into the fixation block 
80, through set screw aperture 86 in fixation block 80, to contact the 
alignment rod 60, to lock the fixation block 80 onto the alignment rod 60. 
The fixation block 80 additionally includes apertures extending vertically 
therethrough for receiving fixation pins 88 for affixing the fixation 
block 80 to the proximal tibia 8. 
In operation, the ankle clamp 50 is attached about the ankle, or about the 
tibia just above the ankle, on the exterior of the skin. The fixation 
block 80 is already interconnected with the alignment rod 60. It is 
preliminarily positioned over the proximal tibia 8, and one of the 
fixation pins 88 is driven into the proximal tibia 8. Thereafter, the 
alignment rod 60 is adjusted to establish proper varus/valgus alignment 
and flexion/extension angulation as is conventionally known. Upon proper 
alignment of the alignment rod 60, the other fixation pin 88 is driven 
into the proximal tibia 8 to completely fix the fixation block 80 to the 
proximal tibia 8 to lock in the proper alignment of the alignment rod 60. 
Then, the fixation block 80 may be locked into position on the alignment 
rod 60. 
After properly aligning and locking in the alignment of the alignment rod 
60, the cutting guide clamps 10 and the cutting guides 20 may be employed. 
The cutting guide clamps 10 are interconnected with the alignment rod 60 
by means of cutting guide linkage 70. Alternatively, the cutting guide 
clamps 10 could directly interconnect with the alignment rod 60 through 
apertures in the cutting guide clamps 10 as shown in FIGS. 1 and 2. As 
shown in FIG. 3, the cutting guide clamp linkage 70 comprises a body 71 
having an alignment rod aperture 72 for receiving and riding the alignment 
rod 60 and a pivot locking set screw 74 which extends into the cutting 
guide clamp linkage 70 through set screw aperture 75 for contacting the 
alignment rod 60 and locking the cutting guide clamp linkage 70 with 
respect to the alignment rod 60. It should be pointed out that it may be 
desirable for the alignment rod 60 to have a flattened surface extending 
longitudinally along the alignment rod 60 for coacting with set screw 74 
for maintaining proper alignment between the cutting guide clamp linkage 
70 and the alignment rod 60. 
The cutting guide clamp linkage 70 also includes a pivot shaft 76 rigidly 
interconnected with the body 71 of the cutting guide clamp linkage 70 by 
member 77 to position the pivot shaft 76 a distance away from the body 71 
such that the cutting guide clamps 10 can be interconnected with the pivot 
shaft 76 and can be properly utilized without interfering with the body 71 
of the cutting guide clamp linkage 70. 
After the alignment rod 60 is properly aligned and locked into position, 
the cutting guide clamp linkage 70 is moved into its approximate desired 
position at the proximal tibia 8. It should be noted that the cutting 
guide clamp linkage 70 of present invention is positioned on the alignment 
rod 60 at the beginning of the procedure, prior to aligning the alignment 
rod 60, and prior to interconnecting the fixation block 80 with the 
alignment rod 60. However, it is within the scope of the present invention 
to provide a cutting guide clamp linkage 70 which is attachable to the 
alignment rod 60 after the alignment rod 60 has been aligned and locked 
into position. 
After the cutting guide clamp linkage 70 is preliminarily approximately 
located, it is locked into place on the alignment rod 60. Thereafter, the 
cutting guide clamps 10 may be interconnected with the pivot shaft 76 by 
means of corresponding pivot apertures 17 in the cutting guide clamps 10. 
As shown in FIGS. 4 and 5, the cutting guide clamps 10 include opposing 
hand grips 12 for grasping and manipulating the cutting guide clamps 10. 
Cross bar members 14 extend from the hand grips 12 to clamp members 18. 
The cross bar members 14 cross over each other at cross over point 15 
whereat the cross bar members 14 have mating recessed portions 16 which 
function to maintain the hand grips 12 in the same plane as the clamp 
members 18. At the cross over point 15, the cross bar members 14 can pivot 
with respect to each other such that movement of the hand grips 12 towards 
each other moves the clamp members 18 together, and likewise, movement of 
the hand grip members 12 away from each other serves to move the clamp 
members 18 apart in the same manner as scissors or pliers. At the cross 
over point 15, the cross bar members 14 have corresponding pivot apertures 
17 for receiving the pivot shaft 76 of the cutting guide clamp linkage 70. 
Thus, the cutting guide clamps 10 pivot about the pivot shaft 76 of the 
cutting guide clamp linkage 70. It should be noted that the cross bar 
members 14 could be interconnected with each other by a rivet or other 
means known in the art, or could be entirely independent pieces which 
coact as set forth above only upon being seated on pivot shaft 76. 
The clamp members 18 of the cutting guide clamps 10 include cutting guide 
adjustment screw apertures 19 at the far ends thereof for receiving A-P 
adjustment screws 30 for adjustably interconnecting the cutting guides 20 
with the clamp members 18, for adjustable movement in the direction shown 
by arrow C in FIG. 4. The clamp members 18 may be adjustably 
interconnected with the cutting guides 20 in any way known in the art. In 
one embodiment, the cutting guide adjustment screw apertures 18 are 
threaded and the cutting guides 20 have corresponding elongated apertures 
28 extending over a portion of the length thereof for receiving the A-P 
adjustment screws at a desired location therealong. The A-P adjustment 
screws include a head 31, a retaining head 32, and a threaded shaft 34. 
When the cutting guides 20 are positioned correctly with respect to the 
clamp members 18, the A-P adjustment screws 30 are tightened down to lock 
the cutting guides 20 onto the clamp members 18 by actuating the head 31 
to turn down the threaded shaft 34 with respect to the clamp member 18. 
Note the retaining head 32 of the A-P adjustment screws prevent the shaft 
34 from being backed off out of engagement with the clamp member 18. 
As shown in FIGS. 7 and 8, respectively, the clamp members 18 are shaped 
with opposing interior edges having chamfers 38 and the opposite exterior 
edges of the cutting guides 20 have mating recesses 39, both of said 
profiles extending along the contacting surfaces of the clamp members 18, 
as seen along line A--A in FIG. 5, and the cutting guides 20, as seen 
along line B--B in FIG. 5, to maintain a proper planar alignment 
therebetween. It should of course be noted that any other method known in 
the art may be employed to maintain the clamp members 18 and the cutting 
guides 20 in alignment. Additionally, the cutting guides 20 may include 
A-P adjustment screw recesses 37 for receiving the head 31 of the A-P 
adjustment screw 30. 
The cutting guides 20 further include tibia attachment means for attaching 
the cutting guides 20 to the tibia 8. Any known attachment means may be 
employed to attach the cutting guides 20 to the tibia 8. As shown in FIGS. 
2 and 4, a preferred attachment means for attaching the cutting guides 20 
to the tibia 8 are pins 36 extending through pin apertures 27 in the 
cutting guides 20. The pins 36 may be captured in the pin apertures 27, or 
they may be entirely separate. Preferably, means exist on the cutting 
guides 20 for preliminarily attaching the cutting guides 20 to the tibia 8 
prior to pinning the cutting guides 20 thereto, so that after proper 
positioning of the cutting guides 20, the hand grips 12 can be actuated by 
squeezing the hand grips 12 together to contact the cutting guides 20 
against the tibia 8 so that the cutting guides 20 are preliminarily 
attached to the tibia 8. Such means may include a plurality of small pins 
captured by the cutting guide 20, or any other suitable means. After the 
preliminary attachment of the cutting guides 20 to the tibia 8, final 
attachment may be made by attachment pins 36 or by any other means known 
in the art. 
The cutting guides 20, importantly, include cutting slots 22 which each 
comprise lower cutting slot guide surface 23 and upper cutting slot 
retaining surface 25, as well as cutting slot entrance and exit 24 at one 
end thereof and cutting slot end wall 26 at the other end thereof. The 
cutting slot 22 is of a length sufficient to extend across the proximal 
tibia 8, at a desired angle to the intermedullary canal, at the widest 
point of the proximal tibia 8, to allow the entire upper surface of the 
proximal tibia 8 to be cut. The cutting slot 22 is of a size sufficient to 
receive a cylindrical milling bit 55 such as that shown in FIG. 2 and 
described in co-pending patent application No. 08/300,379, filed Sep. 2, 
1994 by Goldstein, et al. The milling bit 55 comprises central cutting 
portion 57 having helical cutting teeth along its length for cutting bone. 
The milling bit 55 further comprises spindles 56 extending from the 
central cutting portion 57 for supporting the central cutting portion 57. 
The milling bit 55 is inserted into and received in the cutting slot 22 
through cutting slot entrance 24, along the direction shown by arrow A in 
FIG. 2. Note that the cutting slot entrance 24 may by of a wider slot area 
or an upturned portion of the slot 22 or the milling bit 55 may merely be 
inserted and removed from the slot 22 at an end thereof. The spindles 56 
extend through and coact with the lower cutting guide surface 23 and the 
upper retaining surface 25 of the cutting slot 22 to guide the milling bit 
55 along the cutting slot 22 to resect the proximal tibia 8, along the 
direction shown by arrow B in FIG. 2. At an end of one or both of the 
spindles 56 is a means for engaging the milling bit 55 with a drive means 
such as an electric drill, or other drive means. This engagement means may 
include a hexagonal head on one of the spindles, or any other suitable 
method of engagement known in the art. Additionally, bushings may be 
employed, either on the milling bit 55 or captured by the cutting slot 22, 
to provide a non-metallic bearing between the spindles 56 of the milling 
bit 55 and the cutting slot 22 to avoid galling and to insure smooth 
articulation of the milling bit 55 along the cutting slots 22. 
Importantly, the configuration of the milling bit 55 may be varied in 
accordance with what is known in the art, as long as the cutting device 
can follow the cutting path of the cutting slot to resect the proximal 
tibia. Additionally, it should also be pointed out that other cutting 
tools may be used in accordance with present invention, including an 
oscillating or reciprocating saw or other means for resecting the tibia by 
following the cutting slots on the cutting guides. 
After the cutting guide clamps 10 are preliminarily located along the 
alignment rod 60, the cutting guides 20 are adjusted with respect to the 
clamp members 18 for proper anterior-posterior positioning to extend along 
the proximal tibia 8 for guiding the milling bit 55. Importantly, the 
cutting slots 22 should extend beyond the edges of the proximal tibia 8. 
Once proper anterior-posterior alignment is obtained, the cutting guides 
20 may be locked into place on the clamp members 18. 
Thereafter, a proximal tibial referencing stylus 90 may be attached to a 
referencing bracket 92 on the cutting guides 20. The referencing bracket 
92 may be positioned in any location on the cutting guides 20, or on any 
other convenient component of the tibia resection system of the present 
invention. Alternatively, the referencing stylus 90 may be formed as part 
of a component of the present invention, or as a separate component which 
could function merely by contacting the cutting guides 20 of the present 
invention of any other component thereof. The referencing stylus 90 shown 
in FIG. 6 includes stylus body 94 which may be interconnected with the 
referencing bracket 92 in any manner known in the art, preferably by a 
quick release and connect mechanism or a threaded connection. The stylus 
body 94 supports a stylus arm 96, which is rotatable with respect to the 
stylus body 94 and configured to extend out and down from the stylus body 
94 to contact the proximal tibia 8 at a tip 98 of the stylus arm 96. The 
stylus body 94, arm 96 and tip 98 are sized to contact the proximal tibia 
8 to reference the positioning of the cutting guides 20 to cut the 
proximal tibia at a proper distance below the proximal tibia 8 as is known 
in the art. The stylus arm 96 may include more than one tip 98, such other 
tips extending down from the stylus body 94 in varying distances. 
In operation, one determines the desired location of the stylus tip 98, 
unlocks the cutting guide clamp linkage 70 to permit the linkage 70 to 
move up and down the alignment rod 60, and places the tip 98 on the lowest 
point of the proximal tibia 8 to reference the position of the of the 
cutting guides with respect to the proximal tibia 8 and with respect to 
the alignment rod 60. Thereafter, the cutting guide clamp linkage 70 is 
locked to the alignment rod 60 to lock the cutting guides 20 into the 
proper position on the alignment rod 60, and accordingly, into proper 
position with respect to the proximal tibia 8. Thereafter, the hand grips 
12 are actuated to press the cutting guides 20 against the proximal tibia 
8 to preliminarily lock them into position on the proximal tibia 8. Next, 
the cutting guides 20 are fixed to the proximal tibia 8 by pins 36 or any 
other desired fixation means. The fixation block 80 can then be removed 
from the proximal tibia 8, and the proximal tibia 8 may be resected. 
The cutting operation is similar to the cutting operation set forth in 
co-pending patent application No. 08/300,379, filed Sep. 2, 1994 by 
Goldstein, et al. Essentially, the cutting operation comprises inserting 
the milling bit 55 into the cutting guide slots 22 through the slot 
entrance/exit 24 to position the central cutting portion 57 between the 
cutting guides 20, the spindles 56 extending through the cutting guide 
slots 22. After the milling bit 55 is positioned, the drive means may be 
interconnected therewith, actuated, and the milling bit 55 moved along the 
cutting slots 22 to resect the proximal tibia 8. 
It should be noted that a handle may be provided for attachment to the 
spindle which is not driven so that such spindle may be guided evenly 
through the cutting slots 22 to facilitate the cutting procedure. 
Alternatively, a handle can be provided which interconnects with both 
spindles to further facilitate control of the milling bit 55 during the 
cutting procedure. Additionally, the bushings that fit over the spindles 
56 of milling bit 55 and ride in the cutting slots 22 may be captured in 
the ends of the handle and the milling bit received therethrough. 
Additionally, it should be pointed out that it is within the scope of the 
present invention to modify the cutting slots 22 such that the upper 
retaining surface is eliminated, and the milling bit 55 merely follows the 
lower cutting guide surface 23. With the cylindrical milling bit 55 herein 
described, this is especially viable as the milling bit 55 tends to pull 
down into the bone as it is cutting, thereby primarily utilizing the lower 
cutting guide surface 23 of the cutting guide 20. 
As shown in FIGS. 9-11, various other embodiments of the cutting guides are 
considered within the scope of the present invention. The cutting guide 
120 shown in FIG. 9 is of a generally U-shaped configuration, having 
cutting guide slots 122, lower cutting guide surface 123, upper retaining 
surface 125, pin apertures 127 and alignment rod aperture 128. This 
cutting guide 120 is used in the same manner as the cutting guides 
hereinbefore described, the differences being that the cutting guide 120 
interconnects directly with the alignment rod and that various size 
cutting guides must be provided to accommodate various sized tibias. 
Likewise, the cutting guide 220 shown in FIG. 10 operates in the same 
manner as the cutting guide devices hereinbefore described, but it does 
not include cutting guide clamps. The cutting guide 220 includes cutting 
slots 222, and it interconnects directly with alignment rod by means of 
aperture 228. The distance between facing members 230 can be adjusted by 
moving base members 232 and 234 with respect to each other to size the 
cutting guide 220 for the tibia to be cut. Upon proper sizing, the base 
members 232 and 234 may be locked with respect to each other by set screw 
236 or any other means known in the art. 
FIG. 11 shows an embodiment of the cutting guide for use when the patellar 
tendon, the patella, or the quad tendon interferes with the placement of 
the other cutting guides of the present invention. As shown in FIG. 11, 
the cutting guide 320 may be directly interconnected with the alignment 
rod, and positioned on the tibia as hereinbefore set forth. Basically, 
this embodiment of the invention includes only one cutting guide. The 
cutting guide 320 and the cutting guide slot 322 may be wider than in the 
previous embodiments to help stabilize the milling bit in operation. In 
this embodiment, the milling bit may be first plunged across the tibia, 
and then moved therealong. The milling bit may be spring loaded to 
increase resistance as it is plunged through the cutting guide to bias the 
bit against being plunged too far across the tibia to cause damage to the 
tissue about the tibia. Additionally, a support member, not shown, could 
be provided to extend from the cutting guide 320, over and across the 
tibia to the other side thereof where it could have a slot to capture the 
milling bit and provide additional support thereto. 
Having thus described the invention in detail, it is to be understood that 
the foregoing description is not intended to limit the spirit and scope 
thereof. What is desired to be protected by Letters Patent is set forth in 
the appended claims.