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`US005171244A
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,171,244
`Dec. 15, 1992
`
`.
`
`United States Patent [19]
`Caspari et a1.
`
`[54] METHODS AND APPARATUS FOR
`ARTHROSCOPIC PROSTHETIC KNEE
`REPLACEMENT
`
`[76] Inventors: Richard B. Caspari, 2192 Sheppard
`Town Rd., Maidens, Va. 23102;
`Jeffrey G. Roberts, 3688 Montclair
`Dr., Palm Harbor, Fla. 34684, James
`T. Treace, 2701 Bluffs Dr., Largo,
`Fl 34640
`a‘
`[21] APPL No‘; 462,529 ‘
`.
`[22] Filed:
`
`Jan. 8, 1990
`
`-
`
`4,722,330 2/1988 Russell et al. .
`4,736,737 4/1988 Fafgle e131- -
`4,738,253 4/1988 Buechel et al. .
`4,738,254 4/1988 Buechel et al. .
`4,757,810 7/1988 Reese .
`4,759,350 7/1988 Dunn et a1. .
`goble et a1. ........................ .. 606/66
`4,787,383 11/1988 Kenna '
`
`1
`
`,
`
`ctersen .
`
`4,791,919 12/1988 Elloy et a1. .
`_ 4,822,362 4/1989 Walker et a]. .
`4,825,857 5/1989 Kenna .
`4,830,000 5/ 1989 Shutt .
`4,862,881 9/1989 Shea, Jr. ,
`
`[51] Int. Cl; i ‘ I . I
`_ . _ I " A61B 19/00; A611: 2/38
`[52] US. Cl. ...................................... .. 606/88; 606/87;
`.
`‘306/54; ‘306/80; 128/898; 623/20
`[58] Field of Search ..................... .. 623/18, 20, 39, 40,
`42’ 43, 44’ 45’
`54’ 79’ 80,
`87, 88, 92, 93, 94, 99, 102, 172; 128/898
`_
`References 019d
`U.S. PATENT DOCUMENTS
`
`[561
`
`5,002,547 3/1991 Pogg1e et al. ....................... .. 606/88
`OTHER PUBLICATIONS
`Harry E. Groth, M. D. et al., The MultFRadius m
`T I K
`.h S
`G .d d I
`.
`013
`nee wlt ‘ urgeOn- 111 e
`nstrumcntatlon,
`197,8’ m?- 23-31’ 21mm“ USA
`Ch1tran_]an S. Banawat, M. D., Total Condylar Knee
`Prosthesis Surgical Technique, 1978, p. 2, Howmedica
`Surgical Techniques.
`
`3,255,747 6/1966 Cochran et al. .................... .. 606/93
`4,274,163 6/1981 Malcolm et a1. .................... .. 606/94
`4,349,018 9/1982 Chambers .
`4,421,112 12/1983 Mains et al. .
`4,457,307 7 1984 5'11
`11 .
`4,467,801 82984 vslg?zzide _
`4,474,177 10/1934 whimside _
`4,487,203 12/1984 Androphy .
`4,502,483 3/1935 Lacey -
`4’524'766 6/1985 Pelersen '
`4’567’885 2/1986 Androphy '
`4.567,886 2/1986 Petersen .
`4,574,794 3/1986 Cooke et a1. _
`4,646,729 3/1987 Kenna er a1, _
`4,653,488 3/ 1987 Kenna .
`lz;
`glohclum ~
`4,711,233 12/1987 Brown ................................. .. 606/94
`4,718,413 1/1988 Johnson .
`'
`4,719,908 l/1988 Averill et a1. .
`4,721,104 1/1988 Kaufman 81 a1. .
`
`Y
`
`,
`
`o _
`
`Primary Examiner-Stephen C, Pellegrino
`ASSiSmmExaml-ner_G1enn K_ Dawson
`
`[57]
`ABSTRACT
`_
`Methods and apparatus for prosthetic knee replacement
`permit preparation of tibial plateau and femoral condyle
`surfaces and implant of tibial and femoral protheses
`components with the use of arthroscopic surgical tech
`niques, The bone surfaces are resected by moving a
`rotatin millin cutter lon itudin 11
`re s the be e
`g
`g.
`g.
`2 .y ac s
`“
`surface and movmg the rotating milling cutter substan
`t1ally laterally across the bone. Cement is supplied be
`tween the prostheses and the bone surfaces after posi
`tioning of the prostheses on the bone, and cement bond
`311g 15 an“??? b5; “32mg 5mm to the bone to draw
`e “men 1“ o e
`“e'
`
`.
`
`.
`
`.
`
`.
`
`15 Claims, 12 Drawing Sheets
`
`Smith & Nephew Ex. 1055
`IPR Petition - USP 8,377,129
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 1 of 12
`Sheet 1 of 12
`
`5,171,244
`5,171,244
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 2 of 12
`Sheet 2 of 12
`
`5,171,244
`5,171,244
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`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 3 of 12
`Sheet 3 of 12
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`5,171,244
`5,171,244
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`55.;
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`

`
`US. Patent
`U.S. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 4 of 12
`Sheet 4 of 12
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`5,171,244
`5,171,244
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`2-—.'|'.Iu!_.
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`\|"
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 5 of 12
`Sheet 5 of 12
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`5,171,244
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`
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`
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 5 of 12
`Sheet 6 of 12
`
`5,171,244
`5,171,244
`
`100
`
`
`
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`
`
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15,1992
`Dec. 15,1992
`
`Sheet 7 of 12
`Sheet 7 of 12
`
`5,171,244
`5,171,244
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`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 8 of 12
`Sheet 8 of 12
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`5,171,244
`5,171,244
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`'214
`
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`

`
`US. Patent
`U.S. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 9 of 12
`Sheet 9 of 12
`
`5,171,244
`5,171,244
`
`

`
`US. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 10 of 12
`Sheet 10 of 12
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`5,171,244
`5,171,244
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`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 11 of 12
`Sheet 11 of 12
`
`5,171,244
`5,171,244
`
`/‘/6.24
`
`

`
`U.S. Patent
`US. Patent
`
`Dec. 15, 1992
`Dec. 15, 1992
`
`Sheet 12 of 12
`Sheet 12 of 12
`
`5,171,244
`5,171,244
`
`H6. 25
`
`114
`
`F/é. 29
`
`F/G. 30
`
`

`
`1
`
`0
`
`METHODS AND APPARATUS FOR
`ARTHROSCOPIC PROSTHETIC KNEE
`REPLACEMENT
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention pertains to resection of bones
`for receiving prosthetic components of particular use in
`knee replacement procedures and, more speci?cally, to
`methods and apparatus for arthroscopic knee replace
`ment.
`2. Discussion of the Prior Art
`Prosthetic replacement of the knee is a procedure of
`substantial importance to recreate the knee joint with a
`pain-free functional arc of motion and antero-posterior
`and varus-valgus stability. The knee is, basically,
`formed of medial and lateral tibial plateaus, medial and
`lateral femoral condyles and menisci between the tibial
`plateaus and the femoral condyles along with the patella
`which covers the anterior surface of the knee, and pros
`thetic replacement of the knee as described herein re
`lates to the tibial plateaus, the femoral condyles and the
`menisci. Various types of prostheses are presently avail
`able, as described in detail in Replacement of the Knee,
`Laskin, Denham and Apley, Springer-Verlag Berlin
`Heidelberg, 1984, and are commonly grouped as partial
`or unicompartmental replacements of the medial or
`lateral portion of the tibio-femoral joint, surface re
`placements to prevent contact between worn surfaces
`and jack the joint surfaces apart, linked joints and ?xed
`hinge joints. The type of prothesis employed must be
`matched to the needs of the patient. By selecting the '
`proper prothesis, antero-posterior and varus-valgus
`stability can be achieved by prosthetic replacement
`coupled with bone surfacing or resection. In the past,
`prosthetic replacement has been a last resort in treat
`ment for knee problems due to the facts that prior art
`protheses and surgical procedures have not led to reli
`able, close to natural, results and the open surgery re
`quired results in great trauma and substantial recovery
`time. Much effort has been expended in attempts to
`improve the accuracy with which articular joint sur
`faces can be positioned with leg alignment; however,
`procedures and apparatus available at this time do not
`provide the required accuracy to restore normal leg
`alignment and prevent early failure of the prothesis.
`Open surgery required for prior art prosthetic re
`placements typically necessitates a long incision, on the‘
`order of ten inches, along the anterior midline of the
`knee from above the patella to below the tibial tubercle
`followed by a deep dissection around the medial, border
`of the patella and along the patellar ligament to the
`tibial tubercle with detachment of the medial third of
`the quadriceps attachment from the upper border of the
`55
`patella. The tendinous margin is then pulled downwards
`and medially while the patella is pulled downwards and
`laterally. The quadriceps tendon is then split, and the
`patella is displaced laterally and everted. While the
`above is a simpli?ed explanation of open knee surgery,
`it serves to explain the substantial trauma and recovery
`time associated therewith. Arthroscopic surgery has
`been used for many surgical procedures on the knee to
`avoid open surgery with great success; however, the
`obstacles presented by articular bone surface resecting
`or shaping to receive an implant coupled with the need
`for precise positioning and alignment of the prostheses
`has been insurmountable with arthroscopic procedures
`
`5,171,244
`2
`prior to the present invention. Not only is there a great
`need for an arthroscopic prosthetic knee replacement
`procedure but there is also a great need for improve
`ment in the accuracy of prosthesis placement to restore
`normal leg alignment.
`SUMMARY OF THE INVENTION
`Accordingly, it is a primary object of the present
`invention to overcome the above mentioned disadvan
`tages associated with prior art prosthetic knee replace
`ment surgical procedures with an arthroscopic pros
`thetic knee replacement.
`Another object of the present invention is to accu
`rately resect tibial plateau and femoral condyle planar
`surfaces relative to each other such that the tibial pla
`teau and femoral condyle surfaces are constrained to be
`disposed in planes perpendicular to a substantially verti
`cal reference plane.
`A further object of the present invention is to cement
`a prosthesis to a tissue surface after the prosthesis is
`accurately placed on the tissue surface.
`An additional object of the present invention is to
`perform a least invasive prosthetic knee replacement
`with the use of arthroscopy and requiring only arthro
`scopic size portals.
`The present invention has another object in the per
`forming of all procedures for a prosthetic knee replace- '
`ment, including surface preparation, ?tting and implant
`ing, arthroscopically through small portals enlarged
`only for insertion of the ?nal components.
`Yet an additional object of the present invention is to
`arthroscopically resect tibial plateau and femoral con
`dyle surfaces using existing surface anatomy as a refer
`ence point.
`A further object of the present invention is to im
`prove the mechanical bond created by cement between
`a prosthesis and a bone surface by applying suction to
`the bone to draw the cement into the bone.
`Some of the advantages of the present invention over
`prior art prosthetic knee replacements are that, by using
`arthroscopic surgical techniques and small portals in
`place of the long incisions required for open knee proce
`dures, trauma and recovery time are substantially re
`duced, alignment of the tibial and femoral prosthesis
`components is assured by ?xing the femoral cutting jig
`with reference to the tibial cutting jig and, therefore,
`resecting the femoral condyle with reference to the
`resected tibial plateau, the knee is restored to a normal,
`healthy condition by resecting the tibial plateau and the
`tibial condyle using the existing surface anatomy as a
`reference point, and prostheses are cemented after accu
`rate positioning of the prostheses on the bone.
`Generally, the present invention contemplates the use
`of a milling cutter to prepare a bone surface to receive
`a prosthesis such that bone surfaces can be resected
`through small portals allowing prosthesis implantation
`using arthroscopic surgical techniques and, more partic
`ularly, allowing arthroscopic, unicompartmental, pros
`thetic total knee replacement. Tibial and femoral pros
`thesis components are bonded to the bone surfaces by
`injecting cement after the components are accurately
`positioned on the bone, the cement being injected
`through the components to be received in chambers
`defined by recesses in the ?xation surfaces of the com
`ponents and the cement bond being enhanced by apply
`ing suction to the bone to draw the cement into the
`bone.
`
`40
`
`45
`
`65
`
`

`
`15
`
`25
`
`35
`
`5,171,244
`3
`4
`Other objects and advantages of the present invention
`FIGS. 27, 28 and 29 are perspective views showing
`will become apparent from the following description of
`use of the stylus for positioning the cutter platform for
`the preferred embodiment taken in conjunction with the
`resecting the tibial plateau and the femoral condyle.
`accompanying drawings.
`FIG. 30 is a broken perspective view showing use of
`a gauge for selecting the size of a femoral prosthesis
`BRIEF DESCRIPTION OF THE DRAWINGS
`component.
`FIG. 1 is a perspective view of a tibial jig mounted to
`the tibia in accordance with the present invention.
`FIG. 2 is an exploded view of the tibial jig, a support
`assembly and a milling cutter module in accordance
`with the present invention.
`FIG. 3 is a side view of the apparatus of FIG. 2 in
`position for resecting the tibial plateau.
`FIG. 3a is a view taken along lines 3a—-3a of FIG. 3
`showing a depth of gauge scale.
`FIG. 4 is a front view of the tibial plateau during the
`resecting thereof.
`FIG. 5 is a top view of the tibial plateau after longitu
`dinal cuts are made therein.
`FIG. 6 is a side view of the tibial plateau after resect
`ing to produce a planar tibial plateau surface.
`FIG. 7 is a plan view of the milling cutter module
`mounted on a support platform.
`FIG. 7a is a section taken along lines 7A—7A of FIG.
`7 showing a stop for limiting pivotal movement of the
`milling cutter.
`FIG. 8 is a side view, partly in section, of the milling
`cutter module on a slide member of the platform.
`FIG. 9 is a broken plan view of the milling cutter
`according to the present invention.
`FIG. 10 is a section taken along lines 10—10 of FIG.
`9.
`FIG. 10a is a distal end view of the milling cutter of
`FIG. 9.
`FIG. 11 is a side view of the cutter platform with an
`alignment bridge mounted thereon for drilling holes in
`the femur.
`FIG. 12 is a perspective view of the alignment bridge.
`FIG. 13 is a top view taken along line 13—13 of FIG.
`11.
`FIG. 14 is a top view showing rods passing through
`the holes drilled in the femur for attachment of a femo
`ral jig.
`FIG. 15 is a broken side view partly in section of a
`rod for passing through the femur.
`FIG. 16 is an exploded broken view, partly in section,
`of sleeves received on the rods.
`FIG. 17 is an exploded perspective view of a femoral
`support base.
`FIG. 18 is a top plan view of the femoral support
`base.
`FIG. 19 is a broken side view of the femoral jig with
`the cutter platform and the cutter module mounted
`thereon.
`FIGS. 20, 21 and 22 are perspective views showing
`resecting of a femoral condyle to produce planar poste
`rior, distal and chamfer surfaces, respectively.
`FIG. 23 is a broken section of a holding detent for the
`tibial jig.
`FIG. 24 is an exploded view illustrating the prepared
`tibial plateau and femoral condyle surfaces and position
`ing of the tibial and femoral prothesis components
`thereon.
`FIG. 25 is a side view of a stylus for use in resecting
`the tibial plateau and the femoral condyle.
`FIG. 26 is a perspective view of a module for the
`stylus mounted on the ‘platform slide member.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`The apparatus and method for prosthetic knee re
`placement in accordance with the present invention
`requires only small portals to perform all bone and
`tissue preparation procedures as well as implanting the
`prosthetic tibial and femoral components and cement
`ing the components in place. Accordingly, prosthetic
`knee replacement in accordance with the present inven
`tion can be performed with the use of arthroscopic
`surgical procedures. By “portal” is meant a puncture or
`stab wound of the type made by a plunge cut with a
`scalpel or trocar and of the type commonly used in
`conventional arthoscopic procedures, the size of the
`portal being just large enough to allow insertion of
`instruments.
`A tibial jig 40 in accordance with the present inven
`tion is illustrated in FIG. 1 and includes a lower V
`block 42 adapted to rest just above the malleoli at the
`ankle and an upper V-block 44 adapted to be secured to
`the tibia just below the tibial tubercle. Lower V-block
`42 is connected to a rod 46 telescopingly received
`within a tube 48 connected to upper V-block 44 which
`is formed of a pair of angled members having a plurality
`of holes 50 therein to receive screws 52 extending here
`through and into the tibia to securely mount the tibial
`jig thereon. As best shown in FIG. 2, tube 48 has spaced
`arms 54 and 56 terminating at the angled members of
`upper V-block 44, and an angular adjustment member
`58 has a tongue 60 disposed between members 54 and 56
`with a hole 62 therein for receiving an adjustment screw
`64 extending through corresponding holes in members
`54 and 56. In this manner, the angular adjustment mem
`ber 58 can be pivoted about screw 64 to a desired posi
`tion and the screw tightened to hold the angular adjust
`ment member in place. A longitudinal adjustment block
`66 has a dovetail slot 68 therein to receive a dovetail 70
`on member 58, and a longitudinal adjustment screw 72
`is held in a non-rotating manner in block 66 and carries
`a head 74 having a dovetail slot 76 therein. Block 66 has
`spaced arms between which is mounted a thumbwheel
`78 threadedly engaging adjustment screw 72 such that
`rotation of thumbwheel 78 causes longitudinal axial
`movement of the screw and the head. A block 80 has a
`dovetail 82 received in slot 76 and mounts a cutter plat
`form generally indicated at 84. As shown in FIGS. 3
`and 3a, a longitudinal or depth of cut gauge 86 is
`mounted on an extension 88 of block 66 and carries
`indicia 90 allowing registration with an index mark on
`screw 72 to indicate the depth of a out being made, as
`will be explained in more detail hereinafter. The gauge
`has a zero center mark with indicia extending in either
`direction therefrom in millimeter graduations.
`The platform 84 includes a semi-circular plate 92
`having a curved peripheral edge 94 and a dovetail 96
`slidably received in a dovetail slot 98 in block 80 to
`permit movement of the platform in a lateral direction
`perpendicular to the longitudinal movement of screw
`72. A linear slide member 100 has a distal end 102 pivot
`ally mounted centrally on plate 92 and carries a toothed
`rack 104 longitudinally thereon. The slide member 100
`
`45
`
`50
`
`55
`
`65
`
`

`
`5,171,244
`5
`6
`extends substantially beyond the peripheral edge 94 of
`into the tibia with the upper and lower V-blocks dis~
`plate 92 and carries on its back side a clamp assembly
`posed just below the tibial tubercle and just above the
`including a lever 106 pivotally mounted on cars 108
`malleoli at the ankle, respectively, with a set screw 163
`provided to maintain the position of telescoping mem
`secured to the slide member, the lever 106 having a
`clamping end 110 and an operating end 112 as best
`bers 46 and 48. A portal 164 is formed in the knee for
`shown in FIG. 8. A trigger like member 114 is pivotally
`insertion of an arthroscope 166 for viewing of the knee
`mounted on a lug 116 extending from the slide member
`and the surgical procedure, while a portal 168 is formed
`and has a ?at portion engaging the operating end 112 of
`in the tissue adjacent the tibial plateau, FIG. 1 illustrat
`lever 106 which is biased against the trigger by means of
`ing the portal 168 for use in resecting the medial tibial
`a. compression spring 118. Accordingly, when trigger
`plateau of the left leg. With the tibial jig 40 secured in
`114 is moved toward the slide member (rotated clock
`alignment with the tibia, the apparatus is assembled as
`wise looking at FIG. 8) the operating end 112 of lever
`illustrated in FIG. 3 with the exception that the cutter
`106 is moved toward the slide member causing the
`module is not mounted on the slide member 100 but
`clamping end 110 to move away from the peripheral
`rather a stylus module 170, as illustrated in FIG. 26, is
`edge 94 of plate 92 thereby allowing pivotal movement
`mounted thereon. The stylus module 170 includes a
`of the slide member relative to the plate. When the
`housing having a dovetail slot for receiving the dovetail
`trigger 114 is released, the spring 118 returns the clamp
`120 of the slide member and mounts a stylus 172 having
`four equally spaced positions controlled by detents, not
`ing end 110 to engagement with the plate to hold the
`slide member in the selected pivotal position.
`shown, within the housing. The stylus has a curved
`radially extending tip 174 that can be positioned via the
`The slide member has an elongated dovetail 121 re
`20
`ceived in a slot 122 in a housing 124 of a cutter module
`detents to extend up, down or to either side. The radial
`generally indicated at 126. A pinion 128 having teeth for
`extension of the stylus 174 is preferably equal to the
`engaging rack 104 is mounted on an axle joumaled
`radius of the milling cutter, e.g., 3.5 mm, and the hous
`through housing 124 to terminate at handwheels 132 on
`ing of the stylus module positions the stylus at the same
`either side of the housing. A pneumatic motor 134 has a
`position at which the milling cutter is positioned when
`proximal end receiving drive and exhaust conduits 136
`the cutter module is received on the slide member. With
`the stylus tip turned down, the posterior and anterior
`and a distal end engaging the shaft of a milling cutter
`138 as best shown in FIG. 8. The motor is driven by
`edges of the tibial plateau are contacted with the stylus,
`pressurized ?uid, such as nitrogen or air; and, when the
`and angular adjustment block 58 is pivoted about screw
`drive ?uid is provided at 100 psi, the motor speed and
`64 to alignthe platform with the natural tilt of the tibial
`plateau as sensed by the stylus, the natural tilt being
`torque are 4000 rpm and 50 02-inch, respectively. A
`chamber 140 is formed around the drive coupling and
`normally between 3° and 10° posteriorly. Once the
`natural tilt is established, the stylus is rotated 90 such
`has a port 142 for connection to a source of suction, the
`proximal end of the milling cutter 138 having a hole 144
`that the tip 174 is turned to the right, and the tip of the
`therein for communicating with the chamber and the
`stylus is moved by sliding the plate 92 in block 80 until
`milling cutter 138 being rotatably supported at the distal
`the tip of the stylus contacts the tibial eminence 176 as
`end of the chamber by suitable bearing and journal
`illustrated in FIG. 27. Once the tibial eminence has been
`structure. Stops 146 and 148 are movably secured to the
`located, a screw, not shown, is tightened to secure the
`peripheral edge 94 of plate 92 on opposite sides of slide
`lateral position of the platform. The slide member 100 is
`centrally positioned on the plate 92 during this proce
`member 100; and, as shown in FIG. 7a, are formed of
`4-0
`set screws 150 for engaging the plate 92.
`dure, and the stop 148 is moved to abut the slide mem
`The milling cutter 138, as best shown in FIGS. 9, 10
`ber 100 ‘to prevent pivotal movement of the slide mem
`and 100, includes a shaft having a proximal end 152 for
`ber and the milling cutter mill clockwise looking at
`engaging a locking collet assembly in chamber 140 to be
`FIG. 7. With the tip 174 of the stylus turned down, the
`driven by the pneumatic motor, the shaft being hollow
`lowest point of contact of the tip on the tibial plateau is
`to establish communication between hole 144 in the
`located; and, with the stylus at this contact point,
`proximal end thereof and holes 154 disposed in the
`thumbwheel 78 is locked in place to control the position
`distal portion thereof. The distal portion of the milling
`of the resection to be performed, it being noted that, due
`cutter includes a body 156 having a plurality of helical
`to the dimensional relationship between the cutter mod
`cutting edges 158 extending therealong, and at least one
`ule and the stylus module, the milling cutter will be
`hole 154 is disposed between each pair of body cutting
`aligned with the lowest point on the tibial plateau. As
`edges 158. As shown in FIG. 10, four equally spaced
`shown in dashed lines in FIG. 27, prior to the alignment
`cutting edges are disposed on the ?uted body 156, and
`steps, the anterior portion of the meniscus or cartilage
`has been removed by normal arthroscopic techniques
`holes 154 communicate with a passage 160 formed by
`the hollow shaft of the milling cutter. Cutting edges 162
`leaving a posterior segment indicated at 178 such that
`during the resection procedure, the posterior portion of
`are disposed at the distal end of the milling cutter in a
`plane extending transverse to the longitudinal axis of
`the meniscus provides a cushion to provide the surgeon
`the milling cutter, and each of the body cutting edges
`with an indication of the location of the posterior edge
`of the tibial plateau.
`158 extends from one of the distal end cutting edges 162.
`The milling cutter preferably has a diameter of 7 mm
`To resect the tibial plateau, the stylus module is re
`and the body cutting edges preferably have substan
`moved and the cutter module is placed thereon as illus
`tially radial leading edges.
`trated in FIG. 3; and, since angular, lateral and longitu
`The operation of the apparatus described above to
`dinal adjustments have already been made and set in
`resect a tibial plateau for unicompartmental prosthetic
`place, only linear and pivotal movements of the milling
`knee replacement utilizing arthroscopic surgical tech
`cutter can be made and such movements can be made
`niques will be described with reference to FIGS. 1 and
`only in _a single plane. With reference to FIGS. 4 and 5,
`3. As previously described, tibial jig 40 is secured to the
`it can be seen that initial forward movement of the
`tibia by screws 52 extending through V-block 44 and
`milling cutter produces a longitudinal plunge cut along
`
`50
`
`55
`
`65
`
`25
`
`45
`
`

`
`5,171,244
`7
`8
`the tibial eminence 176 to produce a trough across the
`A femoral cutting jig 228 is mounted to the femoral
`tibial plateau as indicated at 180, it being noted that the
`support base 214 via threaded posts 230 extending
`through the cylindrical protrusions 220 to receive
`milling cutter cuts on its distal end as well as along the
`?uted body thereof. After the ?rst longitudinal cut has
`threaded nuts 232 tightening the femoral cutting jig in
`been made, the trigger 114 is released allowing pivotal
`rigid position relative to the femoral support base. The
`movement of the slide member slightly; and, after the
`femoral cutting jig includes a U-shaped member 234
`trigger is released to clamp the slide member in position,
`having opposite legs pivotally mounted on ?anges 236
`a second longitudinal cut is made by linear movement of
`each of which is rigidly secured to the femoral support
`the milling cutter as indicated at 182. This procedure is
`base via threaded post 230. As best shown in FIGS. 20,
`repeated until the surface of the tibial plateau is covered
`21 and 22, each of the ?anges 236 has holes 238, 240 and
`with troughs having ridges 184 therebetween. The trig
`242 therein positioned relative to the pivotal axis indi
`ger 114 is now depressed to release the slide member;
`cated at 244 to position a support 246 rigidly connected
`and, with the milling cutter disposed over the tibial
`with the U-shaped member 234 in a plane parallel to the
`plateau, the milling cutter is pivoted back and forth to
`plane passing through the rods through the femur as
`sweep the milling cutter over the tibial plateau remov
`illustrated in FIG. 21, a plane perpendicular to the plane
`ing the ridges, the sweeping movement being substan
`passing through the rods as illustrated in FIG. 20, and a
`tially transverse to the longitudinal movements of the
`plane positioned at an angle of 45° to the plane passing
`milling cutter to form the troughs. During the resecting
`through the rods as illustrated in FIG. 22. The position
`procedure, suction is applied to port 142 such that bone
`of the U-shaped member and therefore the support 246
`chips are evacuated via holes 154 and passage 160
`is controlled by means of spring loaded detents
`through the hollow milling cutter. The suction also
`mounted on ?anges 248 secured to the opposite ends of
`serves to cool the surgical site and prevent cavitation.
`the U-shaped member. As shown in FIG. 23, detents
`Once the tibial plateau has been resected, the cutter
`250 are biased inwardly to extend through holes 238,
`module is removed from the platform, and the platform
`240 or 242 with which they are aligned, and can be
`is removed from block 80. An alignment bridge 186, as
`withdrawn by twisting end 252 to cause the end to cam
`illustrated in FIG. 12, is then coupled with block 80 as
`outwardly as shown in phantom compressing a spring
`illustrated in FIGS. 11 and 13, it being noted that block
`254 to move the detent out of the hole. Accordingly, the
`80 remains ?xed relative to the tibia and, therefore, the
`femoral cutting jig ca be accurately positioned in either
`resected planar tibial plateau. The alignment bridge 186
`of the three positions shown in FIGS. 20, 21 and 22 by
`manipulating the detents and pivoting the U-shaped
`includes a dovetail slide 188 received in the slot 98 in
`block 80, and an arm 190 extends at an angle of 45°
`member relative to the femoral support base. The femo
`between slide 188 and a drill guide 192 having parallel
`ral cutting jig illustrated in FIG. 19 differs slightly from
`bores 194 and 196 therethrough. Accordingly, the bores
`that illustrated in FIGS. 20, 21 and 22 in that the sup
`194 and 196 will be disposed in a plane transverse to the
`port 246 is secured at an angle to the U-shaped member
`plane of the resected tibial plateau. With the leg in full
`234; however, the operation is the same in that position
`ing of the femoral cutting jig only requires accurate
`extension, as illustrated in FIGS. 11 and 13, inserts 198
`and 200 are passed through bores 194 and 196, respec
`positioning of the support 246 to which the longitudinal
`tively, to provide elongated guides for drilling parallel
`adjustment block 66 is attached to mount the cutting
`bores through the femur. The bores are drilled through
`platform and the cutting module in a plane perpendicu
`the femur using conventional orthopedic techniques;
`lar to support 246 in the same manner as described
`and. after the bores are drilled through the femur,
`above with respect to mounting of the cutting platform
`threaded rods 204 are passed through each bore as illus
`and the cutting module on angular adjustment block 58
`trated in FIG. 14. As shown in FIG. 15, one of the
`mounted on the tibial jig. FIG. 19 illustrates the milling
`threaded rods 204 is preferably hollow having a passage
`cutter positioned at an angle of 45° to the plane of the
`206 therethrough providing communication between its
`rods 204 through the femur and further illustrates, in
`end and holes 208 centrally located therein. Threaded
`phantom, the milling cutter positioned in planes perpen
`sleeves 210 are disposed on the outer ends of each rod in
`dicular and parallel to the plane of the rods 204. Since
`threaded engagement with the rods while loosely slid
`the plane of the rods 20 is parallel to the planar resected
`ing sleeves 212 are disposed between sleeves 210 and
`tibial plateau, the milling cutter is constrained to move
`the femur, the sleeves being illustrated in FIG. 16 and
`only in planes parallel to a reference plane extending
`shown in position relative to the femur in FIG. 14. With
`perpendicular to the plane of the resected tibial plateau.
`the sleeves tightened in place and the rods passing
`To resect the femoral condyle, the stylus module 170
`through the epicondylar region of the femur, a support
`is mounted on the slide member 100 with the stylus 172
`for resecting the femoral condyle is established relative
`turned upward as illustrated at 256 in FIG. 29 and the
`to the resected tibial plateau since the rods are disposed
`slide member positioned in a plane parallel to the re
`in a plane perpendicular to the planar tibial plateau.
`sected tibial plateau plane, and the stylus is moved to
`With the rods in place, a femoral support base 214 is
`contact the lowermost point on the posterior surface of
`rigidly attached to the rods to prevent any deflection or
`the femoral condyle. Once this point is located, the
`twisting of the rods. The femoral support base 214 in
`depth gauge 86 is moved to align the “zero” point with
`cludesa U-shaped member 216 having upper ends se
`the index line on the screw 72. With the depth gauge so
`cured saddles 218 each of which has a cylindrical pro
`aligned, the stylus module is removed, and the