AU2124701A - Tibial resection instrument - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 DIVISIONAL APPLICATION NAME OF APPLICANT: Smith Nephew, Inc.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street Melbourne, 3000.

IP Australia

R

DoCUrnents (D~\~oo 0 1 5 FFR C Batch No: INVENTION TITLE: "Tibial resection instrument" The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\PHH\2379374 019.DOC 14/2/01 -1I- P:\OPER\PHH\2379374 DIV 018.DOC 14/2101 -2- Tibial Resection Instrument The present invention relates to orthopedic surgical instruments and surgical methods and more particularly relates to an improved apparatus for resecting the patient's proximal tibia for installing a knee prosthesis. Even more particularly, the present invention relates to an improved apparatus for resecting a patient's proximal tibia using a preliminary cutting guide and then secondarily cutting the proximal tibia with a secondary cutting guide that has blades that penetrate the proximal tibia, the blades having upper guide surfaces thereon that guide a sawblade during cutting.

In knee joint replacement surgery, a surgeon typically affixes two prosthesis components to the patient's femur and tibia. These replacement components are typically known as the femoral component and the tibial component.

i The femoral component is placed on a patient's distal femur after the surgeon makes a .:plurality of surgical cuts. One common type of femoral prosthesis has a J-shape. A femoral *ooee prosthesis is usually metallic, having a highly polished outer femoral articulating surface.

20 A common type of tibial prosthesis uses a laterally extending tray that is shaped to conform to the patient's proximal tibia after the proximal tibia has been cut transversely by the surgeon. The tibial prosthesis also includes a stem or plug that extends generally perpendicular to the tray and from the center of the tray. The stem is placed in a surgically formed opening that extends into the patient's intramedullary canal from the transverse cut 25 formed on the proximal tibia.

A plastic polymeric insert is attached to the tibial tray. This insert provides a tibial articulating surface that articulates with the femoral articulating surface as the patient's tibia moves through a full range of motion with respect to the patient's femur.

One of the problems with knee joint replacement surgery is that of accurately fitting the patient. Each patient has a different bone structure and geometry. Even though the surgeon P:\OPER\PHH\2379374 DIV 018.DOC- 14/2/01 -3uses x-rays to study a particular patient's anatomy at the knee, the surgeon does not have a perfect appreciation of the patient's anatomy until after the knee has been surgically exposed and the surgeon begins to make cuts on the femur and the tibia.

Knee prosthetic components are not available in infinite sizes. The surgeon must examine the patient's anatomy, make the requisite surgical cuts and install prosthesis components that fit.

When the surgeon uses bone cement to fix the prosthesis in place, any inconsistencies in the prosthesis fit may, to some extent, be compensated by the bone cement. However, in instances where bone cement is not used, but rather the ingrowth of natural bone is relied on to fix the prosthesis in place, the fit of the prosthesis must be exceptionally good. There is therefore a need to provide tibia resection apparatus which ensures an improved fit for the prosthesis.

:i It is an object of the present invention to meet this need.

o* S• A number of tibial components have been patented that relate to tibial components having a tray, a plastic insert with articulating surface, and a stem portion that provides initial fixation 20 when the prosthesis is implanted. Other patents have issued that relate to cutting .instrumentation for preparing the patient's proximal tibia to receive a tibial prosthetic insert as part of knee joint replacement surgery.

The Murray patent 4,016,606 discloses a knee prosthesis that includes a tibial component 25 with a tray and with a stem adapted to be received in a longitudinal bore in the patient's femur. The stem has one end that is integral with a depending generally spheroidal surface having generally the same radius as the radius of the spheroidal depression in the insert.

In the Chiarizzio patent 4,601,289 there is disclosed a femoral trial prosthesis/rasp assembly used in hip implant surgery. The assembly includes a handle that grips the combination trial prosthesis/rasp in a secure manner by clamping over and locking on to a post on the trial P:\OPER\PHH\2379374 DIV 018.DOC- 14/2/01 -4prosthesis/rasp which later serves as a mounting piece for a femoral prosthesis head used in trial reductions.

A modular tibial prosthesis is disclosed in the Shaw Patent 4,938,769. The Shaw patent discloses a tibial prosthesis for use during a total knee arthroplasty procedure which includes a modular two part tibial component comprising an in-bone anchorage assembly to which is removably attached a tibial tray adapted to receive and retain a bearing insert. Removal of the tray permits access to the interface between the bone and anchorage assembly in the event removal or revision are necessary. In preferred embodiments, the invention affords hybrid fixation of the tibial prosthesis in that bone cement for immediate fixation and adaptation for longer term bone ingrowth are featured. Shaw also discusses the use of porous coatings to enhance fixation.

US Patent 4,938,769 issued to James Shaw discloses an end bone anchorage assembly for a 15 tibial prosthesis that includes an axially elongated central stem and a plurality of elongated fixation pegs spaced from the stem. The stem and the pegs have proximal and distal ends.

S°The proximal ends of the stem define and attachment table. A plurality of structural links interconnect the pegs and the stem. Means is provided for removably attaching a tibial tray S.i to the assembly wherein each of the pegs is connected to the stem by the structural link.

S A tibial component for a replacement knee prosthesis is disclosed in the Lawes et al Patent 5,080,675. Lawes discloses a tibial component for a replacement knee prosthesis S.i comprising a tibial tray for connection to a suitably prepared tibia, the tray carrying fixed lateral and medial condylar bearing components. Only the medial component has a shock absorber located beneath it.

US Patent 5,137,536 issued to Tomishisa Koshino describes a tibial component for an artificial knee joint. The tibial component includes a plate section having an upper surface and a pair of bearing surfaces parts that are adapted to be in sliding contact with a femoral component. A stem portion extends downwardly from a lower surface of the plate section.

A pair of blade like members extend obliquely and posteriorly from the stem. The plate section has a lower surface with a plurality of elongated grooves for improving affinity with P:\OPER\PHH\2379374 DIV 018.DOC 141O respect to the surrounding bone, the grooves including a first group of grooves and a second set of group of grooves extending perpendicularly to the first group of grooves.

An example of a modular tibial support is seen in the Elias Patent 5,246,459 entitled "Modular Tibial Support Pegs for the Tibial Component of a Prosthetic Knee Replacement System". The Elias Patent discloses a modular tibial support peg operable to secure a tibial component of a knee joint prosthesis to a tibia having a groove. The modular tibial support peg includes a cylindrical body with a ridged outer surface operable to engage the groove in the tibia. The modular tibial support peg further includes a plurality of spikes extending inferiorly from the cylindrical body. The spikes are operable to engage the tibia at the inferior end of the groove.

Accordingly, there is also provided a tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis.

An improved method of preparing a patient's proximal tibia with a surgical saw uses cutting instrumentation for guiding the saw when shaping the patient's proximal tibia with cuts to .oo.oi receive a tibial implant.

S.i 20 In this method the patient's tibial intramedullary canal is first drilled to receive an S.intramedullary rod. The surgeon then places the rod in the intramedullary canal and mounts cutting guide instruments to that rod.

oo In the method a first cutting instrument is mounted on the rod above the patient's proximal tibia. The first cutting instrument has transverse cutting guide surfaces for guiding a surgical saw during an initial cutting of the proximal tibia. The first cutting instrument also provides a stylus with an adjustable stylus member that can reference the proximal tibia before cutting begins. The surgeon then sets a selected depth of cut with the stylus and engages the proximal tibial surface with the stylus.

After the depth of cut has been set using the stylus, the proximal tibia is cut with a first transverse cut. During this first cut, the saw tracks the cutting guide surfaces and then P:\OPER\PHH\2379374 DIV OIS.DOC- 14/2/01 -6engages the proximal tibial bone tissue. The first cutting instrument and its stylus are then removed.

A second cutting instrument is then mounted on the rod above the patient's proximal tibia.

The second cutting instrument has guide surfaces externally of the proximal tibia for guiding a surgical saw blade and a blade member thereon for cutting longitudinally into the proximal tibial. After the secondary cutting instrument is positioned to a selected depth within the proximal tibia, a secondary transverse cut is made on the proximal tibia using the secondary cutting instrument. The saw first tracks the guide surfaces externally of the proximal tibia and then tracks a cutting guide surface on the blade member. The present invention concerns such a second cutting instrument.

In the preferred method, the primary and secondary cuts are made generally perpendicular to the rod and thus to the patient's intramedullary canal.

1 :i In a preferred embodiment of the present invention, the blade member on the secondary cutting instrument includes a plurality of flat blades that are thrust completely into the S: patient's proximal tibial bone tissue. The blades are embedded in the proximal tibia. The top surface of the blade member is slightly below the surface of the first transverse cut. This 20 allows the surgeon to use the secondary cutting instrument to track not only the secondary cutting instrument externally of the tibia but also to track a guide surface provided on the upper surface of the blade member that have been imbedded in the patient's proximal tibial bone tissue.

i. 25 For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals, and wherein: FIGURE 1 is a perspective schematic view illustrating preliminary tibial preparation; FIGURE 2 is a schematic perspective view illustrating attachment of an ankle clamp and the preferred embodiment of the apparatus of the present invention illustrating the tibial cutting block and tibial stylus portions thereof; P:\OPER\PHH\2379374 DIV 018.DOC 14/2/01 -7- FIGURE 3 is a perspective view illustrating the tibial cutting block and the tibial stylus portion of the preferred embodiment of the apparatus of the present invention; FIGURE 4 is a fragmentary perspective view illustrating a cutting of the proximal tibial using the tibial cutting block; FIGURE 5 is a perspective exploded view illustrating the tibial cutting block and the tibial stylus portion of the preferred embodiment of the apparatus of the present invention; FIGURE 6 is an exploded perspective view illustrating the tibial stylus; FIGURE 6A is a sectional elevational fragmentary view illustrating the tibial stylus; FIGURE 7 is a top view illustrating the tibial stylus portion of the preferred embodiment of the apparatus of the present invention; FIGURE 8 is partial section view illustrating the tibial stylus; FIGURE 9 is partial perspective view of the tibial stylus; FIGURE 10 is a fragmentary view of the tibial stylus; FIGURE 11 is another fragmentary sectional view of the tibial stylus; 15 FIGURE 12 is a fragmentary sectional view of the preferred embodiment of the :i "apparatus of the present invention; FIGURE 13 is a front elevational view of the tibial cutting block portion of the ooooo S. preferred embodiment of the apparatus of the present invention; FIGURE 14 is a top view of the tibial cutting block of the preferred embodiment of 20 the apparatus of the present invention; FIGURE 15 is a sectional view of the tibial cutting block of the preferred embodiment of the apparatus of the present invention; 9* FIGURE 16 is a partial sectional view of the tibial cutting block of the preferred embodiment of the apparatus of the present invention; FIGURE 17 is a perspective view illustrating placement of the tibial secondary prep- •guide portion of the preferred embodiment of the apparatus of the present invention; FIGURE 18 is a perspective view illustrating the tibial secondary prep-guide and a secondary finishing of the proximal tibia; FIGURE 19 illustrates installation of a trial tibial prosthesis in the patient's proximal tibia; P:\OPER\PHH\2379374 DIV 018.DOC 1412J01 -8- FIGURE 20 illustrates the trial femoral prosthesis and the trial tibial prosthesis installed respectively on the patient's distal femur and proximal tibia and prior to rotation to the tibial trial prosthesis; FIGURE 21 is a perspective view of the tibial secondary prep-guide portion of the preferred embodiment of the apparatus of the present invention; FIGURE 22 is a frontal elevational view of the tibial secondary prep-guide; FIGURE 23 is an elevational side view of the tibial prep-guide; Figures 1-4 illustrate a preliminary preparation of the patient's distal tibia as part of the method of the present invention. In Figure 1, the patient's tibia 10 is shown as is the proximal tibia 11. A drill 13 is used to track the patient's intramedullary canal 12 for receiving a reamer 21. Also shown in Figure 1 is the patient's femur 14 that has already been surgically prepared to receive a trial femoral prosthesis. The distal femur 15 is typically prepared with anterior and posterior cuts that are parallel to each other, a distal cut I 15 that is generally perpendicular to the anterior and posterior cuts, and diagonally extending °chamfer cuts that extend between the distal cut and the respective posterior and anterior cuts.

0o :In Figure 2, an ankle clamp 16 has been installed at the patient's ankle 17 and with an alignment sleeve 18 that is positioned generally parallel to the patient's tibia. The sleeve 18 20 provides a coupling 19 for forming a connection with the bottom of tibial cutting guide 20 of the present invention. Ankle clamps 16 are commercially available and can be seen for example in the Steele patent 5,197,944, incorporated herein by reference.

In Figure 3, the tibial cutting guide 20 can be seen placed adjacent the patient's proximal 25 tibia 11. In Figures 3 and 5-6, the tibial cutting guide 20 can be seen attached to the tibial stylus 50, and the assembly of cutting guide 20 and stylus 50 being attached to reamer 21 mounted in the patient's intramedullary canal. Stylus 50 is shown more particularly in Figures 5-12. Cutting block 20 is shown more particularly in Figures 13-16.

Cutting block 20 includes a block body 22 that includes a pair of upper flanges 23 and a pair of lower flanges 24. Slots 25, 26 extend between the upper flanges 23 and the lower flanges 24. The slots 25, 26 provide a guide for a flat cutting blade such as the cutting blade 73 P:\OPER\PHH\2379374 DIV 018.DOC 14/2/01 -9shown in Figure 4 which can be a commercially available powered saw. The saw blade 73 cuts through the patient's proximal tibia 11 as shown in Figure 4 along a line 74 that is generally perpendicular to the patient's intramedullary canal. In Figure 4, the block 22 has been attached to the proximal tibia 11 using a plurality of bone spikes Tibial cutting block 20 further provides a center portion 22 that can be used to attach the cutting block 22 to the tibial stylus 50 and to ankle clamp 16 at coupling 19. Cutting block body 22 provides a lower attachment portion 28 having a plurality of cylindrical bores 29 therethrough as shown in Figures 13 and 14. These cylindrical openings 29 provide a cylindrical shape that corresponds generally to the outer configuration of a bone spike One or more bone spikes can be placed through a corresponding plurality of the openings 29 for affixing the block 22 to the patient's proximal tibia after alignment has been accomplished using elongated reamer rod 21 placed in the patient's intramedullary canal, the stylus 50, and ankle clamp 16.

Vertical rod 31 extends from coupling 19 to center portion 27 of tibial cutting block 22. A set screw 32 threadably engages opening 33 of central portion 28 of cutting block 22.

Cylindrical socket 34 receives the upper end of vertical rod 31. The set screw 32 can be tightened against the rod as it occupies the cylindrical socket 34.

upper cylindrically-shaped internally threaded opening 35 allows the cutting block 22 to be attached to tibial stylus 50. Vertical post 36 extends between stylus 50 and cutting block *.i 22. The post 36 has a central longitudinal axis that is perpendicular to the plane defined by slots 25, 26. Further, the central longitudinal axis of post 36 is parallel to the central 25 longitudinal axis of reamer rod 21 that is mounted in the patient's intramedullary canal. The post 36 has a lower end 37 with a pair of flanges 38, 39 having a recess 40 therebetween.

An upwardly projecting portion 41 of the center portion 28 of cutting block 22 registers in the recess 40. Further, the flanges 38, 39 closely conform to the projecting portion 41 upon assembly. A threaded connection can be used to form a connection between the threaded opening 35 and bolt 49 that extends through vertical bone 46 of vertical post 36. A bolted connection can be used to assemble the vertical post 36 to the cutting block 22, for example.

P:\OPER\PHH2379374 div II8.doc-14/2)lI A pair of shoulders 44, 45 at the upper end of vertical post 36 register in an elongated slot 53 on tibial stylus 50. The upper end 43 of post 36 has a transverse cross section that corresponds in size and shape to the transverse cross section of the longitudinally extending slot 53. Slot 53 extends through horizontal beam 51 of tibial stylus 50. The slot 53 communicates with a longitudinal opening 52 in the upper surface of the horizontal beam 51. A transverse probe holder 54 extends at generally right angles to the beam 51.

A bushing 55 extends upwardly from the connection between beam 51 and probe holder 54. The bushing 55 provides a vertical open ended bore 56 that receives reamer 21. Set screw 57 can be used to tighten bushing 55 and the entire tibial stylus 50 to reamer 21.

Internally threaded opening 70 receives the set screw 57.

Probe holder 54 includes a pair of sides 58, 59 each having an elongated vertically extending probes 60, 61 respectively. The probe holder 54 has an upper generally flat ,°.oosurface 62 that is perpendicular to the central longitudinal axis of bore 56 and to the central longitudinal axis reamer rod 21. Each probe 60, 61 moves vertically in an opening 66, 67 respectively. A pair of horizontal openings 68, 69 carry detent locking members 63, 64 .o respectively. The detent locking members 63, 64 can be spring loaded with springs 97, 98. Each of the detent locking members 63, 64 have openings that allow the probes 60, 61 to pass therethrough. Each probe 60, 61 provides a plurality of vertically spaced teeth 76 thereon (see Figure Spaces between the teeth 76 are engaged by the respective detent locking member 63, 64 at stop 96 when they are released, thereby affixing the position of each of the probes 60, 61 relative to the probe holder 54. A stop pin 101 holds each detent locking member 63, 64 in its opening 68, 69.

25 Longitudinal opening 52 is surrounded by side walls 72 and by longitudinally extending shoulders 71. This allows the placement of a bolt 49 into slot 52 and through the center of vertical bore 46 of vertical post 36 for attaching to threaded opening 35. Further, the head 43 of the bolt 49 rests on the shoulder 71 transferring load thereto.

In Figures 17-18 and 21-23, there can be seen tibial secondary prep guide 75. Guide has an instrument body 76 that includes a pair of spaced apart vertical posts including the P:\OPER\PHH\2379374 div 01 8.do.-I4/(i2A) -11 post 77 and the post 82. Post 77 carries a cylindrical cutting element 78 with a plurality of circumferentially spaced and radially extending cutting blades 79-81. The post 82 supports a pair of flanged portions including upper flanges 83 and lower flanges 84.

A pair of flat cutting blade guide slots 85, 86 are positioned between the upper flanges and the lower flanges 83, as shown in Figures 21-23. During use, the surgeon places the tibial secondary prep guide over the reamer 21 that is installed in the patient's intramedullary canal. This registers the three cutting blades 79-81 and the cylindrical cutting element 78 at the center of the patient's proximal tibia 11, as shown in Figure 17.

The surgeon hammers the flat side 88 of instrument body 76 driving the cutting blades 79- 81 into the proximal tibia 11 as shown in Figures 17-18. The surgeon hammers the surface 88 until the blades 79-81 are just beneath the surface of proximal tibia 11 as shown in Figure 18. This allows the surgeon to shave a layer of tissue from proximal tibia 11 with S 15 great precision. The saw blade 89 is supported not only by the flanges 83, 84, but also by the upper surfaces 90 of blades 79-81 which are in a common plane with the upper surface 91 of the flange 84, as shown in Figure 31. The dotted line 102 in Figure 21 shows the path taken by saw blade 89 to secondarily cut the proximal tibia.

After the secondary cut is made to the proximal tibia 11, a trial prosthesis can be installed on the patient's distal tibia 11. In Figures 19-20 a tibial trial prosthesis 92 is shown as installed into the patient's intramedullary canal 12. The tibial trial prosthesis 92 can include three components, a metallic plate or tray 93, a stem or plug 94, and a plastic trial :o insert 95. In Figure 20, a tibial prosthesis 92 has been installed by the surgeon on the 25 patient's proximal tibial 11. The surgeon has also installed a trial femoral prosthesis 100 on the distal femur The following table lists the parts numbers and parts descriptions as used herein and in the drawings attached hereto.

P:%OPER\HHQ~379374 dix' ()tdo.I14A/II2 12 0 0* 0 0 *0 0 *0 0 *00* 0* 0 *000** Part Number 11 12 13 14 16 17 18 19 21 22 23 24 25 26 27 28 29 PARTS LIST Description tibia proximal tibia intramedullary canal drill femur distal femur ankle clamp ankle alignment sleeve coupling tibial cutting guide elongated reamer rod cutting block body upper flange lower flange horizontal slot horizontal slot center portion attachment portion cylindrical bores P\OPERPHH2379.174 div U~Xo-jd4t02/01 13 bone spikes 31 vertical rod 32 set screw 33 internally threaded opening 34 cylindrical socket internally threaded opening 36 vertical post 37 lower end 38 flange 39 flange recess *41 projecting portion head :44 shoulder shoulder :46 vertical bore 47 rees 47 recess 49 bolt tibial stylus P:\OPER\PHH\2379374 div I18.doc-14/02/) 14- 51 horizontal beam 52 longitudinal opening 53 longitudinal opening 54 probe holder bushing 56 vertical open ended bore 57 set screw 58 side 59 side 60 probe 61 probe 62 flat surface 63 detent locking member 64 detent locking member bolted connection 66 opening 67 opening 68 horizontal opening 69 horizontal opening internally threaded opening 71 longitudinally extending shoulder 72 side wall P:\OPER\PHH\2379374 div 018 .doc.-14l)2 73 saw blade 74 transverse cut tibial secondary prep guide 76 body 77 vertical post 78 cylindrical cutting element 79 blade blade 81 blade 82 vertical post S. 83 upper horizontal flange 84 lower horizontal flange cutting guide slot 86 cutting guide slot 87 open ended vertical bore 88 flat surface 89 blade upper surface 91 upper surface 92 trial prosthesis 93 tray PNOPERPHHU379374 div I)18doc-14M))I -16- 94 stem insert 96 stop 97 spring 98 spring 99 opening 100 opening 101 stop pin 102 transverse cutting plane S" Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the 5 embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (19)

1. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) a blade portion for forming a connection between the instrument body and the patient's proximal tibia, the blade member having a sharp edge portion that can cut into the cancellous tissue of the patient's proximal tibia and a trailing edge that defines a secondary cutting guide surface; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting guide surfaces are references to the patient's intramedullary canal; and 15 d) wherein the embedded blade member secondary cutting guide surface defines a plane with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface and the secondary cutting guide surface during use.

2. The tibial cutting guide instrument of claim 1 wherein the instrument body is 20 generally U-shaped. S3. The tibial cutting guide instrument of claim 1 further comprising an anvil portion that enables a user to drive the instrument body at the blade member into the patient's °proximal tibia.

4. The tibial cutting guide instrument of claim 1 wherein the blade member comprises a plurality of radially spaced blade members. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a P:\OPER\PHH\2379374 div 0 1d c-]4/02/I1L -18- surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting guide surfaces are referenced to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that defines a plane with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface and the secondary cutting guide surface during use; and e) wherein the secondary cutting guide surface is embedded in the tibia during use.

6. A tibial cutting guide instrument for resecting a patient's transversely cut proximal S•tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the )oo. cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting guide surfaces are reference to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that defines a plan with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface and the secondary cutting guide surface during use; e) an anvil portion that enables a user to drive the instrument body at the blade member into the patient's proximal tibia; and P:\OPER\PHH\239374 di, 0(18doc-14/21l01 -19- f) wherein the blade is embedded during use within the tibia cancellous bone.

7. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting guide surfaces are referenced to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that 15 defines a plane with the primary cutting guide surface so that the cutting instrument abuts S" .both the primary cutting guide surface and the secondary cutting guide surface during use; •and e) wherein the instrument body is generally U-shaped, having a pair of generally parallel leg members connected by a bridge member, and wherein the primary 20 cutting surfaces and secondary cutting surfaces are attached respectively to the leg members. oe

8. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: 25 a) an instrument body having a primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being P:\OPER\PHH237.374 div O'18doc.14)24A1 connectable to the instrument body so that the primary cutting guide surfaces are referenced to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that defines a plane with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface and the secondary cutting guide surface during use; and e) wherein the rod has an axis that defines an axial line that tracks the patient's intramedullary canal, and the blade member occupies a plane that intersects said rod axis.

9. The tibial cutting guide instrument of claim 8 wherein there are a plurality of blade members, each intersecting said rod axis. The tibial cutting guide instrument of clam 9 wherein said rod tracks an axial line i "that coincides with the patient's intramedullary axis and wherein the cutting guide surfaces 15 are generally parallel to said rod and said axis. A tibial cutting guide instrument for resecting a patient's transversely cut proximal *.i tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a 20 surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; Sb) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body s that the primary cutting guide surfaces are referenced to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that defines a plane with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface and the secondary cutting guide surface during use; and P:\OPER\PHH\2379374 div I18.doc-l4M/OI -21- e) wherein there are at least a pair of blade members, each disposed about a bushing that attaches to the rod, each of said blade members forming a flat plane, and the planes being generally perpendicular to the rod.

12. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having a primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) means for forming a connection between the instrument body and the patient's proximal tibia, said means including a blade member that can cut into the cancellous tissue of the patient's proximal tibia; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting guide surfaces are 15 referenced to the patient's intramedullary canal; d) wherein the blade member has a secondary cutting guide surface that ooooo S• defines a plane with the primary cutting guide surface so that the cutting instrument abuts both the primary cutting guide surface during use; and e) wherein the instrument body is generally U-shaped, having a pair of spaced S 20 apart generally parallel leg portions and a transversely extending bridge member that is generally perpendicular to the leg portions, and further comprising an opening that extends through one of the leg portions for supporting the body on the rod at the opening.

13. The tibial cutting guide instrument of claim 12 wherein the bridge member has an anvil surface thereon that enables the user to apply hammer blows therefor for driving the blades into the patient's tibial cancellous bone tissue.

14. The tibial cutting guide instrument of claim 13 wherein the cutting blade has a cutting edge that defines a plane generally aligned with the tibial intramedullary canal, and an opposite proximal edge that defines that secondary cutting guide, said secondary cutting guide surface being an elongated linear cutting guide surface that is generally transverse to P:\OPER\PHH\2379374 div (0II.doc-14/02/A) -22- the intramedullary rod during use. The tibial cutting guide instrument of claim 13 wherein there are a plurality of cutting blade members mounted on the second end portion of the body, each of the cutting blades forming an angle with the other.

16. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia with a generally flat cutting blade to receive a tibial prosthesis comprising: a) an instrument body having first and second end portions; b) the first end portion of the instrument body having a first cutting guide surface thereon for guiding the flat cutting blade in preparing a patient's proximal tibia with generally flat transverse cuts to receive a tibial prosthesis; c) an intramedullary rod for referencing the patient's tibial intramedullary canal; 15 d) the second end portion of the instrument body having an intramedullary rod opening that enables the instrument body to be mounted to the intramedullary rod and transverse cutting guide surfaces that extend generally transverse to the intramedullary rod opening; and e) the second end portion of the instrument body including longitudinally 20 extending cutting blade having a cutting edge that defines a plane generally aligned with the intramedullary canal and generally perpendicular to the first cutting guide surface, said longitudinally extending cutting blade being positioned in the patient's cancellous tibial bone tissue during use; and f) the second end portion of the instrument body having a second cutting 25 guide surface thereon that occupies a common cutting guide plan with the first cutting guide surface and being defined by a flat trailing edge of the longitudinal cutting blade.

17. The tibial cutting guide instrument of claim 16 wherein the opening is generally cylindrical.

18. A tibial cutting guide instrument for resecting a patient's transversely cut proximal P:\OPER\PHH\2379174 div II0l.doc-14/12/01 -23 tibia to receive a tibial prosthesis comprising: a) an instrument body having first and second end portions; b) the first end portion of the instrument body having cutting guide surfaces thereon for preparing a patient's proximal tibia with transverse cuts flat to receive a tibial prosthesis; c) an intramedullary rod for referencing the patient's tibial intramedullary canal; d) the second end portion of the instrument body having an intramedullary rod opening that enables the instrument body to be mounted to the intramedullary rod; e) the transverse cutting guide surfaces being generally transverse to the intramedullary rod opening; f) a cutting blade mounted on the second end portion of the instrument body, said cutting blade having a cutting edge that defines a plane generally aligned with the intramedullary canal, said cutting blade being sized and shaped to cut into the patient's 15 cancellous tibial bone tissue; and g) wherein the cutting blade is sized and shaped to fit within the patient's tibia. ee*

19. The tibial cutting guide instrument of claim 18 wherein the cutting blade is sized to fit within the patient's tibia cancellous bone tissue. The tibial cutting guide instrument of claim 19 wherein the blade has a distal *i cutting surface and a proximal cutting surface, the proximal cutting surface being the secondary cutting guide surface. 25 21. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having a transverse primary cutting surface thereon for guiding a surgeon's cutting knife during a reshaping of a patient's proximal tibia to receive a tibial prosthesis member; b) a blade for forming a connection between the instrument body and the patient's proximal tibia, said blade member having a cutting edge that cuts into the P:\OPER\PHH\2379374 div .doc-14/02/I) -24- medullary tissue of the patient's proximal tibia during use, embedding the blade in the medullary tissue; c) a rod for tracking the patient's intramedullary canal, said rod being connectable to the instrument body so that the primary cutting surfaces are referenced to the patient's intramedullary canal; and d) wherein the blade member has a secondary cutting guide surface that defines a plane with the primary cutting guide surface so that the cutting instrument engages both the primary cutting guide surface and the secondary cutting guide surface during use.

22. A tibial cutting guide instrument for resecting a patient's transversely cut proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having first and second end portions; b) the first end portion of the instrument body having cutting guide surfaces 15 thereon for preparing a patient's proximal tibia to receive a tibial prosthesis; c) an intramedullary rod for referencing the patient's tibial intramedullary S: canal; d) the second end portion of the instrument body having an intramedullary rod opening that enables the instrument body to be mounted to the intramedullary rod; 20 e) the transverse cutting guide surfaces being generally transverse to the intramedullary rod opening; and Sf) a cutting blade mounted on the second end portion of the intramedullary canal, said cutting blade having a cutting edge that defines a plane generally aligned with the intramedullary canal, said cutting blade having a cutting edge that is sized and shaped 25 to cut into the patient's cancellous tibial bone tissue, embedding the blade in said bone tissue during use.

23. A tibial cutting instrument for preparing a patient's proximal tibia to receive a tibial prosthesis comprising: a) an instrument body having first and second end portions; b) the first end portion of the instrument body having first transverse cutting P:\OPERTPHHU379374 div 018doc-14/02I)0 guide surface thereon for preparing a patient's proximal tibia to receive a tibial prosthesis; c) the transverse cutting guide surfaces being perpendicular to the patient's tibia; d) a cutting blade mounted on the second end portion of the intramedullary canal, said cutting blade having a cutting edge that defines a plane generally aligned with the tibia, said cutting blade being embedded within the patient's cancellous tibial bone tissue during use; e) the cutting blade having a second transverse cutting guide surface that defines a plane with the first cutting guide surface; and f) wherein the surgeon can track the first and second cutting guide surfaces during a resection of the patient's proximal tibia.

24. The tibial cutting guide instrument of claim 23 wherein the blade is embedded within the patient's tibial cancellous bone tissue during use.

25. A tibial cutting guide instrument substantially as herein described with reference to SFigures 17, 18 and 21 to 23 of the accompanying drawings. 0

26. The steps, features, compositions and compounds disclosed herein or referred to or 20 indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more or said steps or features. 0e DATED this 14th day of February, 2001 U. 25 SMITH NEPHEW, INC. By Its Patent Attorneys DAVIES COLLISON CAVE