WO1999040864A1

WO1999040864A1 - Tibial resection guide

Info

Publication number: WO1999040864A1
Application number: PCT/US1998/002819
Authority: WO
Inventors: Ramon B. Gustilo; William D. Lew; Richard S. Hammett; Douglas W. Cooper
Original assignee: Midwest Orthopaedic Research Foundation
Priority date: 1998-02-12
Filing date: 1998-02-12
Publication date: 1999-08-19

Abstract

This invention (100) resection guide system is a for joints. The resection guide system (100) is especially advantageous (100) for resecting the proximal tibia. One embodiment of the resection guide system includes a cutting block (114) and structure for vertically positioning the cutting block (114) and for aligning the cutting block (114) to conform to the patient's leg anatomy. Another embodiment provides a guide to enable a surgeon to further resect tibial portions intersecting the previously resected tibial planar surface. The guide transfers a measurement to the bone and provides a guide for the resection.

Description

TIBIAL RESECTION GUIDE

Field of the Invention

The invention relates to joint arthroplasty, especially knee arthroplasty and total knee arthroplasty. More specifically, the invention relates to devices which enable the surgeon to efficiently and accurately resect proximal tibial portions prior to placing prostheses thereon.

Background of the Invention Although the discussion herein focuses on knee joints, the devices described are applicable for other orthopaedic utilities as well. The knee joint enables a person's leg to flex or articulate during movement. At the knee, a lower bone (tibia) meets an upper bone (femur). Proximate the knee, the femur has two projections known as femoral condyles. Femoral condyles engage fibrocartilage at the upper end of the tibia. The knee joint is held together by ligaments, capsule, muscle, and tendons. Four ligaments are especially prominent in knee structure, with one ligament on either side of the knee and two ligaments in the center. Of the center ligaments, one ligament is oriented toward the front and one toward the back. The patella or knee cap is a piece of bone supported in front of the knee joint. Functionally, the patella acts as a shield. The knee joint may be rendered nearly or totally inoperative by extended and heavy use, disease, or trauma. Often, the best therapy is total replacement (arthroplasty). During total knee arthroplasty, the femoral and tibial surfaces joined at the knee are totally replaced. The first step in this process is the removal of the condylar surfaces and some underlying portions thereof. The distal end of the femur is resected to provide clearance for a femoral prosthetic component. Similarly, a proximal portion of the tibia is resected to provide a relatively flat surface for a tibial prosthetic component.

A person's weight is transferred from the head of the femur proximate the hip to the ankle. Proper alignment of the knee must be maintained when femoral and tibial prosthetic devices are installed to - 2 -

allow the proper transfer of weight to continue. In order for the prostheses to function properly, femoral and tibial surfaces arising from these resections must be correctly aligned. These surfaces must also be the proper distance apart so that the planned prostheses will fit and function properly.

Alignment of resecting guides prior to surgical resection has traditionally been done by using a long straight metal rod. One end of the metal rod is aligned with the center of the femoral head. The other end is aligned with the center of the ankle. The center of the femoral head is determined either from an X-ray or, less preferably, estimated by establishing a point located the width of three fingers medial to the superior iliac spine. When aligned, the rod should bisect the center of the knee components and should be generally perpendicular to a tibial and femoral resection plane. Arthritic knees may have varus or valgus deformities and corresponding bone defects or gaps. Resection planes in which these defective portions are exposed may not be satisfactory for supporting replacement prostheses. Presently, the surgeon must either install a prosthetic device over a resected bone with an exposed defective gap and fill the defect under the component with bone cement or a spacer, for example, or resect the tibia still farther away from the knee to remove the defect or gap and insert a thicker prosthetic component. If the surgeon makes a further resection, a guide would be desirable so as to ensure that the resected portion is the correct shape and size. Thus, there is a need for a resection guide system which enables the surgeon to quickly and efficiently align a cutting block so that installed prostheses will fit and operate correctly. There is also a need for a resection guide system which will enable a surgeon to quickly and accurately determine where to vertically situate a resection so that the resection removes only as much bone tissue as necessary.

There is a further need for a resection guide system which enables the surgeon to quickly and efficiently make a further resection to remove - 3 -

defective bone portions, the resected portion being a desired size and shape.

Summary of the Invention The present invention meets these needs by providing a resecting guide system to enable a surgeon to resect a portion of a bone proximate an articulating joint of a patient. The resection forms at least one planar surface for placing a replacement prosthesis thereon. The resecting guide system may include a cutting guide, means for aligning the cutting guide, and means for vertically adjusting the cutting guide. The cutting guide may be affixable to an exterior portion of the bone. The cutting guide may include means for guiding the resection such that the resection results in, or forms, the planar surface. The means for aligning the cutting guide are configured such that the planar surface will be generally perpendicular to an anatomical alignment feature of the patient. The resection guiding means may include a first saw slot. The resecting guide system may be configured such that the saw slot is generally perpendicular to the aligning means.

The resection guiding means may include a second saw slot. The second saw slot may be distally inclined from an anterior bone surface. The angle of inclination may be between about 0° and 10°, between about 4° and 8°, or about 4°. The cutting guide may be detachable from a remainder of the resecting guide system after being affixed to the exterior portion of the bone. The aligning means may include an intramedullary alignment rod. The aligning means may further include means for extramedullary alignment. The extramedullary aligning means may include an extramedullary alignment rod, an alignment rod with a telescoping section, or a light strip alignment device.

The resecting guide system may further include means for determining a vertical location of the planar surface. The vertical location determining means may include means for continuous vertical adjustment. The continuous vertical adjustment means may include a - 4 -

rack and pinion assembly or an advancing screw. The vertical location determining means may be incremental and may include a spring plunger cooperating with a vertical member, the vertical member with a plurality of bores defined therein, the plunger being biased in one of the bores. The resecting guide system may further include means for determining a distance between the cutting guide and a surface of the bone to be resected. The distance determining means may include a pivotable member, the pivotable member being disposable on the cutting guide. The distance determining means may further include depth determining means, the depth determining means disposable proximate the pivotable member. The depth measuring means may include a depressible element, which contacts the bone surface. The depressible element may include a scale for measuring the distance.

The resecting guide system may further include a surface reference with a reference edge for referencing a first resected planar surface. The cutting guide may display a cutting guide surface, the cutting guide surface being vertically and angularly adjustable with respect to the reference edge. The cutting guide surface serves as a guide for resecting the second planar surface. The resecting guide system may further include means for positioning said surface reference, with the surface reference positioning means being disposable in an intramedullary canal and detachably and adjustably connectable to the surface reference. The resecting guide system may further include means for transferring a bone measurement to be used in resecting the second planar surface, the transferring means determining the vertical and angular relationship of the cutting guide surface relative to the reference edge. The transferring means may include a reference block with reference surfaces. The reference surfaces may include an angular surface and a slot. The slot includes a planar surface. The angular surface may be generally horizontal to the planar surface of the slot. The angular surface is disposed against the cutting guide surface and a portion of the reference edge is disposed in the slot when the cutting guide is being vertically and angularly adjusted relative to the reference - 5 -

edge.

There is also provided a method or process for affixing a cutting guide on a bone to be resected proximate an articulating joint, with the resection forming at least one planar surface for placing a replacement prosthesis thereon. The process includes the steps of: providing a cutting guide with a cutting guide surface; disposing the cutting guide on the articulating surface, the cutting guide surface being oriented in a first vertical plane; positioning the cutting guide proximate the articulating surface; aligning the cutting guide; and affixing the cutting guide to the bone. The process may further include the step of determining a first distance from the reference edge to a point on the articulating surface. The process may further include the step of vertically aligning the cutting guide a second distance from the first vertical plane, the second distance including the first distance. The process may further include the step of resecting a spine from an articulating surface of the bone. The process may still further include the step of determining the alignment of the cutting guide with an anatomical feature.

There is also provided a process for affixing a cutting guide on a bone proximate a first planar area in order to resect the bone and thereby form a second planar area. The cutting guide includes a guide surface, the cutting guide being detachably and adjustably connectable to a member with a planar surface guide. The cutting guide also being detachably and adjustably connectable to a generally elongated member. The process includes the steps of: defining a longitudinal cavity in the bone; adjusting the cutting guide surface relative to the planar reference guide; disposing the elongated member in the longitudinal cavity; and affixing the cutting guide to a surface of the bone. The process may further include the step of detaching the cutting guide from the member with the planar surface and the elongated member. The cutting guide surface may be adjusted by using a reference block. The reference block displaying a slot and an angular surface, the reference edge of the planar surface guide being disposed in the slot and the angular surface being disposed against the guide surface. Brief Description of the Drawings

Figure 1 is a perspective exploded view of a proximal resection guide system of the invention and a proximal portion of a tibia to be resected;

Figure 2 is a perspective view of an upper horizontal member of the invention;

Figure 3 is a perspective view of a lower horizontal member of the invention; Figure 4 is a perspective view of the cutting block of Figure 1;

Figure 5 is a perspective sectional view of an extramedullary alignment rod of Figure 1;

Figure 6 is a perspective sectional view of another embodiment of an extramedullary alignment rod of Figure 1; Figure 7 is a perspective view of the guide of Figure 1;

Figure 8 is a perspective view of a depth probe of Figure 1;

Figure 9 is a perspective view of another embodiment of a depth probe of Figure 1;

Figure 10 is an exploded perspective view of a second embodiment of the upper and lower horizontal members of Figure 1;

Figure 11 is an exploded perspective view of a third embodiment of the upper and lower horizontal members of Figure 1;

Figure 12 is a perspective view of a proximal tibial spine being resected; Figure 13 is a perspective view of a sizing insert being placed over a partially resected proximal portion of the tibia of Figure 12;

Figure 14 is a perspective view of an intermedullary tibial canal being drilled to accommodate insertion of an intramedullary alignment rod of Figure 1; Figure 15 is a perspective view of the proximal resection guide system of Figure 1 assembled and, in its collapsed configuration, the cutting block to be affixed on an anterior proximal surface of a tibia to be - 7 -

resected and the depth probe measuring the distance between the horizontal lower slot and the lowest point of the defect in its extended configuration;

Figure 16 is a perspective view of the proximal resection guide system of Figure 15 being affixed to the anterior surface of the tibia to be resected;

Figure 17 is a perspective view of the cutting block of Figure 1 being examined for proper alignment when affixed to an anterior surface of a tibia, the knee portion thereof magnified; Figure 18 is a perspective view of a proximal tibial section being resected by a surgical saw, the surgical saw applied through slots within the cutting block of Figure 1;

Figure 19 is an exploded perspective view of another embodiment of a tibial resection guide system and of a portion of a tibia to be resected; Figure 20 is a perspective view of the stem member of the tibial resection guide system of Figure 19;

Figure 21 is a perspective view of the tibial surface reference of the angular tibial resection guide of Figure 19;

Figure 22 is a perspective view of the cutting guide of the angular tibial resection guide of Figure 19;

Figure 23 is a perspective view of the link of Figure 19;

Figure 24 is a perspective view of one embodiment of the reference block of Figure 19;

Figure 25 is a perspective view of the angular tibial resection guide of Figure 19 assembled prior to adjustment;

Figure 26 is a perspective view of the angular tibial resection guide of Figure 19 being adjusted for a tibial resection;

Figure 27 is a perspective view of the angular tibial resection guide of Figure 19 affixed to an anterior surface of a tibia to be resected; Figure 28 is a perspective view of the tibia being resected using the cutting guide of Figure 19;

Figure 29 is a perspective exploded view of a resected tibia and a - 8 -

tibial prosthesis, the tibial prosthesis including a wedge component; and

Figure 30 is a fragmentary side plan view of an alternate embodiment of a tip of a depth probe of Figure 8.

Detailed Description

The features of the invention embody means for proper placement of a surgical device on a bone to be resected and are improvements to placement and guiding means disclosed in U.S. Patent Application Nos. 08/529,243, now U.S. Patent No. , and 08/918,924, the entire disclosures of which are hereby incorporated by reference.

While specifically addressing the tibia, the invention described herein is generally applicable to a corresponding bone in virtually any articulating joint. In Figure 1, one embodiment of the resection guide of the present invention is indicated as proximal tibial resection guide 100. Proximal tibial resection guide 100 includes upper horizontal member 110, lower horizontal member 112, cutting block (guide) 114, continuous advancing screw 116, intramedullary alignment rod 118, extramedullary alignment rod 120, guide 122, and depth probe 124.

Referring to Figures 1 and 2, upper horizontal member 110 includes first (hereinafter distal) block 132, connecting element 134, and second (hereinafter proximal) block 136. Distal block 132 displays upper and lower surfaces 140, 142 and proximal and distal ends 144, 146. Distal block 132 further defines bore 148. Bore 148 extends from upper to lower surfaces 140, 142. In this embodiment bore 148 is generally centrally disposed. Referring to Figure 2, exemplary connecting element 134 extends between distal block 132 and proximal block 136. Connecting element 134, in this embodiment, extends from an upper portion of proximal end 144 of distal block 132. Connecting element 134 defines slot 152 and exterior and interior surfaces 154, 156. However, a person of ordinary skill in the art will appreciate that certain other shapes for connecting element 134 are possible while achieving the objectives of this invention.

Proximal block 136 displays upper and lower surfaces 160, 162, first - 9 -

and second ends 164, 166, and front surface 168, and defines bore 170 and cavity 172. In this embodiment, connecting element 134 is formed as an extension from a lower portion of proximal block 136 at second end 166. Bore 170 extends from upper surface 160 and opens into cavity 172. Cavity 172 further extends from bore 170 to lower surface 162. Threads 174 are present on the periphery of bore 170. Opening 176 extends from front surface 168 and opens into a lower portion of cavity 172. Bore 170 and cavity 172 are generally disposed within proximal block 136 and are generally coaxially aligned. Referring to Figures 1 and 3, lower horizontal member 112 generally includes horizontal bar 180, vertical bar 182, and first (hereinafter proximal) element 184. In this embodiment, horizontal bar 180, vertical bar 182 and proximal element 184 are unitary. However, a person of ordinary skill in the art will appreciate that other methods of joining and configuring these elements are possible within the scope of this invention. Vertical bar 182 displays front and top surfaces 186, 188. Scale 190 is present on front surface 186. Vertical bar 182 defines generally cylindrical bore 192, which preferably extends from top surface 188 to a lower surface of horizontal bar 180. Proximal element 184 displays respective upper, front, and side surfaces 196, 198, 200 and a lower surface. First and second bores 202, 204 are defined in proximal element 184 and extend from upper surface 196 to the lower surface thereof. Threaded openings 206, 208 are also defined in proximal element 184 and extend from surface 200 and open into respective bores 202, 204. Threaded opening 210 extends from side surface 200 and opens into bore 192. As depicted in Figures 10 and 11, ball plungers (or set screws) 211 or the like may be used within openings 206, 208.

As seen in Figures 1 and 4, unitary cutting block 114 may include lower portion 212 and slot portion 214. Cutting block 114 presents a left surface and opposing right surface 216, and rear surface 218. If cutting block 114 is viewed from above, rear surface 218 is preferably arcuate, thereby giving the rear portion of cutting block 114 a generally concave - 10 -

shape most suitable for use with these preferred applications. Different bone structures may permit alternate shapes. Lower portion 212 presents front surface 220 and defines cavity 222 and bores 224, 226. Cavity 222 is generally square or rectangular in cross section and is bordered by margin 228 proximate front surface 220 in this embodiment. Cavity 222 extends through lower portion 212 between margin 228 and rear surface 218, and is configured to accommodate horizontal bar 180 of lower horizontal member 112. In this embodiment, one or more bores 224 flank cavity 222. Bores 224 extend between front surface 220 and rear surface 218 and are generally parallel to cavity 222 in this embodiment. Also in this embodiment, lower portion 212 defines bores 226 extending between the left surface of cutting block 114 and rear surface 218 and between right surface 216 and rear surface 218. Bores 226 may angle inwardly as they approach rear surface 218. Slot portion 214 generally includes respective lower, middle, and upper leaves 230, 232, 234, each having front edges 236, 238, 240, respectively. Upper leaf 234 further displays upper surface 242. A bevel may be present proximate front edges 236-240 and the left surface of cutting block 114 and between front edges 236-240 and right surface 216. In this embodiment, front edge 236 of lower leaf 230 is generally continuous with margin 228. Leaves 230-234 generally present a stepped appearance to facilitate access and use. Leaves 230-234 provide cutting guide surfaces and are unitarily joined proximate the left and right surfaces of cutting block 114. Respective lower and upper saw slots 244, 246 are defined between lower leaf 230 and middle leaf 232 and between middle leaf 232 and upper leaf 234. Lower saw slot 244 extends generally horizontally and is parallel to cavity 222. The plane of saw slot 244 may be orthogonal to axis 286 when tibial resection guide system 100 is assembled.

Upper saw slot 246 inclines toward lower saw slot 244 as viewed from front surface 220. The incline of upper saw slot 246 may be between about 0° and 10°, about 4° and 8°, or about 4° from the plane of saw slot 244. Bores 248 are defined within leaves 230-234. In this embodiment, a bore - 11 -

248 is present proximate each front corner of slot portion 214. Of course, it may be appreciated that any number of saw slots may be present in an embodiment of the present invention and that the angle of inclination of a saw slot will depend on the specific joint to which the embodiment is to be employed.

As shown in Figure 1, exemplary advancing screw 116 includes knurled head 260 and shaft 262. Shaft 262 further includes threaded portion 263 and tip 264. Threaded portion 263 and tip 264 are separated by constriction 266. Threads are present on portion 263 and annular ribs are defined on tip 264.

As also seen in Figure 1, intramedullary alignment rod 118 includes handle 280 and shaft 282. Handle 280 and shaft 282 are unitary in this embodiment. However, there are a number of ways of functionally joining handle 280 and shaft 282. Also in this embodiment, shaft 282 terminates in rounded tip 284.

Referring to Figures 1 and 5, extramedullary alignment rod 120 includes outer telescoping section 290 and inner telescoping section 292. Inner telescoping section 292 terminates in tip 294. Tip 294 and the remainder of inner telescoping section 292 are separated by constriction 296. In this embodiment, tip 294 is generally spherically shaped. However, tip 294 may assume any of a number of differing geometries to facilitate ease of use. An additional inner telescoping section 292 may extend from the other end of outer telescoping section 290 in some embodiments. Swagging means may be present to prevent inner and outer telescoping sections 290, 292 from being separated in this or other embodiments. Outer telescoping section 290 is sized and shaped such that it is snugly accommodated within either of bores 202, 204 of lower horizontal member 112.

Another embodiment of an extramedullary alignment rod is depicted in Figure 6 generally as 300. Extramedullary alignment rod 300 includes outer telescoping section 302, middle telescoping section 304, and inner telescoping section 306. Inner telescoping section 306 terminates in - 12 -

tip 308. Tip 308 is separated from the remainder of inner telescoping section 306 by constriction 310. As with the case of extramedullary alignment rod 120, outer telescoping section 302 is accommodated snugly within bores 202, 204. While extramedullary alignment rod 300 includes sections 304, 306, it should be appreciated that any number of telescoping sections may be present.

Referring to Figure 7, guide 122 generally includes guide member 314 and cylindrical (anchoring) member 316. Guide member 314 displays upper surface 318 and a lower surface. One or more bores 322 are defined in guide member 314. Bores 322 extend between upper surface 318 and the lower surface of guide member 314. However, a slot may be present in place of bores 322. Cylindrical member 316 terminates in first end 324 and rounded tip 326. Collar 328 is affixed, or unitary, to an approximate midpoint of cylindrical member 316. A fastener such as screw 330 may be present to mate guide member 314 and cylindrical member 316. The portion of cylindrical member 316 between tip 326 and collar 328 fits snugly in bore 248 of cutting block 214.

As depicted in Figure 8, one embodiment of a depth probe 124 includes outer casing 340, inner portion 342, and collar 344. Outer casing 340, in turn, displays first end 346 and a second end threadably received in collar 344. Outer casing 340 further defines central cavity 350. References 352 are formed by a bevel proximate first end 346. Inner portion 342 may be envisioned as including upper portion 356 and lower portion 358. Upper portion 356 displays surface 360. Scale 362 is present on surface 360. Also in this embodiment, both cavity 350 and upper portion 356 are semicircular in cross section. However, it should be appreciated that other cross sectional geometries are suitable. Upper portion 356 is shaped to be accommodated snugly within central cavity 350. Exemplary lower portion 358 is generally cylindrical and terminates in tip 364. Collar 344 is threadably received proximate the second end of outer casing 340. In this embodiment, upper and lower portions 356, 358 are unitary and may include a collar proximate the junction thereof. A coiled spring may be - 13 -

disposed about lower portion 358. The collar proximate the junction of upper and lower portions 356, 358 will not pass through the spring.

Collar 344 is unitary in the embodiment shown in Figure 8. However, collar 344 may include cylindrical member 365 and extension 366. Cylindrical member 365 defines threads present on an interior surface thereof. These threads mate with threads proximate the second end of outer casing 340. In this embodiment, extension 366 fits snugly into bores 322 of guide 122. Extension 366 defines an opening through which lower portion 358 is slidably received. The opening admits portion 358, but will not admit the spring. Thus, the spring serves to bias lower portion 358 toward first end 346.

An alternate embodiment to tip 364 is shown in Figure 30 as angulated tip 367. Tip 367 includes shaft 368 and angled member 369. Shaft 368 and angled member 369 are joined at bend 371. Member 369 terminates in tip 373. Tip 367 is especially useful when depth probe 124 cannot be positioned directly over a tibial surface.

An alternate embodiment to depth probe 124 is indicated generally at 370 in Figure 9. Depth probe 370 broadly includes head 372 and shaft 374. In this embodiment, head 372 is knurled. Shaft 374 displays outer surface 376. Scale 378 is present on outer surface 376.

When resection guide system 100 is assembled upper and lower horizontal members 110, 112 are mated. Upper and lower horizontal members 110, 112 are mated by disposing vertical bar 182 into cavity 172 such that scale 190 is visible through opening 176. Advancing screw 116 is then threaded into bore 170 and through bore 192 until constriction 266 is aligned with opening 210. Fastening means, such as set screw 382, is received into opening 210, thereby fixing screw 116 in place, yet allowing it to be rotated. Guide system 100 is further assembled by inserting horizontal bar 180 into cavity 222. Alternate embodiments to upper and lower horizontal members

110, 112 are depicted in Figures 10 and 11. In Figure 10, a first alternate embodiment is depicted generally as 400. Embodiment 400 includes upper - 14 -

and lower horizontal members 402, 404. Upper horizontal member 402 includes first (hereinafter distal) block 406, connecting element 408, and second (hereinafter proximal) block 410. Distal block 406 and connecting element 408 are generally similar to distal block 132 and connecting element 134 discussed above. Proximal block 410 displays upper and lower surfaces 416, 418, first and second ends 420, 422 and front and right surfaces 424, 425. Bore 426 and cavity 428 are defined within proximal block 410. Bore 426 extends from right surface 425 and opens into cavity 428. Cavity 428 extends from upper surface 416 to lower surface 418. Opening 432 extends from front surface 424 and opens into cavity 428.

Spring plunger 436 includes head 438, shaft 440, and element 442. Tip 443 of element 442 is visible in Figure 10. Element 442 is slidingly disposed within shaft 440 as is a spring. Element 442 is affixed to head 438. The spring thus biases head 438 to shaft 440. Threads 444 are defined on the exterior surface of shaft 440.

Lower horizontal member 404 includes horizontal bar 449, vertical bar 450 and first (hereinafter proximal) element 451. Horizontal bar 449 and proximal element 451 may be configured similarly to horizontal bar 180 and proximal element 184 in lower horizontal member 112. Vertical bar 450 displays front surface 452 and right surface 453. Scale 454 is present on front surface 452. A multiplicity of generally linearly aligned bores 456 are formed in vertical bar 450. Bores 456 extend inwardly from right surface 453. Bores 456 are generally overlapping in this embodiment. However, it should be appreciated that various spacings for bores 456 are possible.

To assemble embodiment 400, cutting block 114 and horizontal bar 180 are mated as discussed above. To mate upper and lower horizontal members 402, 404, vertical bar 450 is disposed into cavity 428. Spring plunger 436 is threadably received in bore 426 until tip 443 is disposed in one of bores 456. To vertically adjust upper and lower horizontal members 402, 404, head 438 of spring plunger 436 is pulled away from proximal block 410. Upper and lower horizontal members 402, 404 then - 15 -

may be moved farther away or toward each other to a desired distance. Upon attaining the desired distance, head 438 is then released, allowing tip 443 to seat into another bore 456. Embodiment 400 enables a user to adjust upper and lower horizontal members 402, 404 to discrete distances therebetween.

In Figure 11 another embodiment of the adjusting mechanism is denoted generally at 470. Adjusting mechanism 470 includes upper horizontal member 472, lower horizontal member 474, and pinion mechanism 476. Upper horizontal member 472 includes first (hereinafter distal) block 480, connecting element 482, and second (hereinafter proximal) bracket 484. Distal block 480 is generally similar to distal blocks 406 and 132. Connecting element 482 includes first connector arm 492 and second connector arm 494. Second connector arm 494 includes section 495. Section 495 is disposed at a greater distance from first connector arm 492 than is the remainder of second connector arm 494. First and second connector arms 492, 494 define cavity 496. An enlarged portion 497 of cavity 496 is defined between section 495 and first connector arm 492. First connector arm 492 and section 495 also define linearly aligned apertures 498. Exemplary proximal bracket 484 includes frame 504. Frame 504 generally defines opening 506. While unitary in this embodiment, frame 504 may be envisioned as including horizontal frame members 507, 508 and vertical frame members 509, 510. Frame 504 is generally perpendicular to connecting element 482. Lower horizontal member 474 includes horizontal bar 511, vertical bar 512, and first (hereinafter proximal) element 513. Horizontal bar 511 and proximal element 513 may be similar to horizontal bar 180 and proximal element 184.

Vertical bar 512 displays front surface 514 and a rear surface. Scale 518 is present on front surface 514. Rack 520 is mounted proximate the rear surface of vertical bar 512. Rack 520 defines a multiplicity of generally horizontal ribs 522. Pinion mechanism 476 includes pinion 530, knob 532, - 16 -

pin 534, and set screw 536. Although unitary in this embodiment, pinion 530 may be envisioned as including large and small diameter portions 538, 540. A multiplicity of ribs (or teeth) 542 extend generally longitudinally from the surface of large diameter portion 538. Bore 544 is generally coaxially defined within pinion 530 in this embodiment. Knob 532 defines bore 548. Small diameter portion 540 fits snugly within bore 548 in this embodiment. Moreover, pin 534 disposes snugly within bore 544.

To assemble embodiment 470, cutting block 114 is mated to horizontal bar 449 as described above. Upper horizontal member 472 is mated to lower horizontal member 474 by extending vertical bar 512 into cavity 497 proximate frame 504. Upper and lower horizontal members 472, 474 are then secured together in an adjustable relationship by installing pinion mechanism 476. Pinion mechanism 476 is installed by mating pinion 530 and knob 532. Pinion 530 and knob 532 are mated by disposing small diameter portion 540 of pinion 530 within bore 548 of knob 532. Mated pinion 530 and knob 532 are then placed within enlarged portion 497 such that teeth 542 of pinion 530 mesh with ribs 522 of rack 520 and such that bore 544 of pinion 530 aligns with apertures 498 on arms 492, 494. Pin 534 is disposed through apertures 498 and bore 544, then affixed in place by any number of methods known to the art. Knob 532 and small diameter portion 540 may also define radially oriented bores which align when pinion 532 and knob 540 are mated. These bores are first aligned and knob 532 is then affixed to pinion 532 by installing set screw 536. Once firmly affixed, rotating knob 532 will also rotate pinion 530, thereby vertically adjusting upper and lower horizontal members 472, 474.

A proximal tibial portion is resected according to the present invention by a process beginning with a step depicted in Figure 12. This depicts proximal tibial section 580 with tibial spines 582 disposed between lateral and medial condyles 584, 586. Figure 12 depicts surgical oscillating saw 590 resecting tibial spines 582. After resection, the middle of the upper portion of tibia 580 is relatively flat. As shown in Figure 13, the proximal end of tibia 580 is then sized by fitting various sizes of insert 594 thereover. - 17 -

In this embodiment, inserts 594 are conveniently available in small, medium, large, extra-large, magnum, and magnum-plus sizes. Insert 594 may be manipulated easily by fitting a tip of advancing lever 596 into an outer aperture therein. Insert 594 defines central aperture 598 and a plurality of smaller apertures 600. This and other embodiments of exemplary insert 594 and advancing lever 596 are disclosed in above- referenced U.S. Patent Application No. 08/529,243, now U.S. Patent No.

Once a correctly sized insert 594 has been determined, insert 594 is secured to the proximal tibia by installing fixation spike 602 through each aperture 600 as shown in Figure 14. With plastic insert 594 now in place, drill bushing 606 is placed in aperture 598. Drill bit 608 is then inserted into bore 607 and used to drill and ream the intramedullary canal. In this embodiment bit 608 is approximately 9.5 (± 1.0) mm in diameter, although this may vary. Insert 594 is then removed from the proximal tibia and a proximal tibial resection guide such as the embodiment generally depicted at 100 is placed thereon, as depicted in Figure 15.

Shaft 282 of intramedullary alignment rod 118 is inserted into bore 148 of horizontal upper member 110 and into the newly drilled intramedullary canal of tibia 580. Upper horizontal member 110 is then lowered until lower surface 142 of distal block 132 contacts the top of the recently resected proximal tibia. Upper horizontal member 110 is further adjusted to contact upper surface 242 of cutting block 214. Adjustment is by means of rotating advancing screw 116 in this embodiment. Thus located, saw slots 244, 246 within cutting block 114 are located some unknown distance above the medial and lateral articular surfaces. When exemplary upper horizontal member 110 contacts upper surface 242 of cutting block 114, the reading on scale 190 is zero. Guide 122 is installed by inserting cylindrical or anchoring member

316 in either of bores 248. So inserted, guide 122 pivots horizontally. Depth probe 124 is then inserted into one of bores 322. Guide 122 and - 18 -

inserted depth probe 124 are then pivoted until depth probe 124 is positioned above the lowest point on the tibial articular surface. Inner portion 342 is then depressed until tip 364 contacts the tibial surface. A reading is made by means of aligning references 352 with marks on scale 362. In this example, scale 362 is graduated in millimeters. Guide and depth probe 122, 124 are then removed and placed similarly in bore 248 on the other side of cutting block 114 and the procedure is repeated. Thus, the distance from lower saw slot 244 to the lowest tibial point has been determined. Proximal resection guide system 100 will now be configured to resect tibia 580 proximate the lowest articular point thereon. If depth probe 370 is used in lieu of depth probe 124, shaft 374 is accommodated in one of bores 322. Tip 379 is allowed to rest on the tibial surface. Scale 378 is read where it intersects surface 318.

To make a resection of the proximal tibia, the measured distance from saw slot 244 to the lowest condylar point is determined per above. Once determined, the measured distance is added to a thickness of the tibial component to be placed thereon. The total of the distance and tibial component thickness determines the total depth of resection on proximal tibia 580. Cutting block 116 and mated lower horizontal member 112 are lowered by rotating advancing screw 116 until the predetermined distance is reflected by reading scale 190. As shown in Figure 16, a plurality of drill bits 612 are inserted through apertures 224 and drilled into the anterior tibia, thus fixing cutting block 114 to tibia 580. As shown in Figure 17, extramedullary alignment rods 120 are then placed in each of bores 202, 204, kept in position with ball plungers 211, and extended.

Proper positioning of cutting block 114 is then determined by alignment with an anatomical feature. For example, tip 294 of extramedullary alignment rod 120 would be disposed directly above a midpoint 588 on the ankle of the patient and tip 294 of the other extramedullary alignment rod 120 would be disposed above ball joint (femoral head) 589 of the patient's femur. If the alignment is not correct, one or both bits 612 are removed and cutting block 114 is repositioned and - 19 -

resecured. Once the correct position has been established, cutting block 114 may be further affixed to tibia 580 by means of placing one or more fixation spikes 602 into bores 224, 244. Alternatively, a light strip alignment device could be used in conjunction with, or in place of, alignment rods 120. One example of such a light strip alignment device is generally disclosed in the above-referenced U.S. Patent Application No. 08/529,243.

Proximal resection guide system 100 is prepared as a cutting guide by removing upper and lower horizontal members 110, 112 and intermedullary alignment rod 118 from cutting block 114, now secured to tibia 580. However, alignment may be checked at any time by reinserting lower horizontal member 112 and extramedullary alignment rod 120 as described above. In this embodiment, a level resection may be made through saw slot 244. A resection with an angled, posterior tilt may be made through inclined upper saw slot 246. A cut through inclined slot 246 would meet a cut through level saw slot 244 approximately in the middle of the tibial plateau if slot 244 angles toward slot 242 at 4°. After resection is complete, cutting block 114, along with drill bits 612 and fixation spikes 602, are removed from tibia 580.

Many osteoarthritic knees have an associated varus or valgus deformity with a corresponding bone defect. When proximate a point of resection, these deformities must also be resected from the proximal tibial region. After these deformities are resected, a wedge or generally rectangular augmentation device may be used under the tibial component of the prosthesis. These augmentation devices may have varying thicknesses and shapes corresponding to tibial prosthetic components for differently sized knees. These augmentation devices may be located in either the medial or lateral condyles of either right or left knees. These augmentation devices are generally discussed below and may be made in varying thicknesses and shapes. For example, thicknesses of 10 mm and 15 mm have proven to be useful. These augmentation devices may also be made to correspond to knee and prosthetic device sizes, such as small, medium, large, extra-large, magnum and magnum-plus. To this end, - 20 -

another exemplary tibial resection guide is depicted generally at 700 in Figure 19. Tibial resection guide 700 broadly includes adjustable tibial trial tension (ATTT) device upper platform 702, stem member 704, tibial surface reference 706, cutting guide 708, link 710, adjustment knobs 712, and one or more reference blocks 714. ATTT device upper platform 702 is disclosed in the above-referenced U.S. Patent Application 08/529,243. ATTT device upper platform 702 includes a cylindrical projection which disposes in the pre-drilled intramedullary canal. Bore 703 is defined in the cylindrical projection of platform 702. An antirotation key extends from the cylindrical projection. The antirotation key is configured to mate into slot 732 (described below).

Referring to Figures 19 and 20, stem member 704 includes head 720 and shaft 722. Head 720, in turn, may be envisioned as including threaded portion 724, flange 726, and collar 728. Threads 729 are formed on the radial exterior of threaded portion 724. Shaft 722 terminates in rounded tip 730. Slot 732 is defined within shaft 722 and may extend from tip 730 to an approximate mid-point of shaft 722.

As seen in Figures 19 and 21, tibial surface reference 706 includes link 740 and vertical member 742. Slot 743 is defined by link 740. Vertical member 742 displays lower edge 744 and includes upper cylindrical member 746. Cylindrical member 746 defines bore 748. Threads 750 are defined within cylindrical member 746 proximate bore 748.

Referring to Figures 19 and 22, cutting guide 708 is generally triangular in cross section. Cutting guide 708 displays a pair of upper sloping surfaces 760 and lower surface 762. Cutting guide 708 defines bore 764 and a multiplicity of apertures 766. Bore 764 is disposed proximate the apex of cutting guide 708. Threads 768 are formed in cutting guide 708 proximate bore 764. Link 710 is depicted in Figure 23 and defines bore 782 and slot 780. Adjustment knobs 712 are generally depicted in Figure 19.

Reference knobs 712 may be male or female as needed in assembling and adjusting resection guide 700 as described below. - 21 -

Each of reference blocks 714 are unitary in this embodiment. However, each reference block 714 may be envisioned as including middle portion 786 and two end portions 788, 790. Each end portion 788, 790 has been machined to form a specific set of reference surfaces with angular and dimensional surfaces for conforming cutting guide 708 as will be described below. For example, end portion 790 has been machined to form four planar surfaces 792, 794, 796, 798. Each planar surface 792-798 terminates in extensions 800, 802, 804, 806. Extensions 800-806 extend beyond adjacent planar surfaces 792-798. Triangular projections 808, 810 are shown in Figure 24. Two other triangular projections cannot be seen. Slots 812, 814 are formed between triangular projections 808, 810 and extensions 800-806. Angular surfaces 816, 818 and two other angular surfaces not depicted in Figure 24 are also present on triangular projections 808, 810 and are opposite slots 812, 814. Various bone deformities may intersect the resection planes made by using resection guide system 100. Resection guide system 700 enables the surgeon to make further resections to remove these deformities. These further resections may be either wedge-shaped or rectangular when viewed anteriorly. Thus, the surfaces present on ends 788, 790 of exemplary reference block 714 enable cutting block 708 to be adjusted relative tibial surface reference 706 to accommodate small, medium, large, extra-large, magnum, and magnum-plus sized tibial trays 594 and wedges 820. Moreover different embodiments of reference block 714 may be made to accommodate either left or right joints and to accommodate either wedge or rectangular prosthetic augmentation members. These prosthetic augmentation members are positioned and secured between insert 594 (or some other prosthetic device) and the remaining tibia If the resected area is generally rectangular instead of generally triangular in cross section, angled surfaces such as surface 816 will be generally parallel to corresponding planar surface 792.

Resection guide 700 may be assembled as depicted in Figure 19. Threaded portion 724 of stem member 704 is passed through link 740 until - 22 -

the bottom of link 740 abuts collar 728. At this point flange 726 will be disposed and aligned within slot 743. A female adjustment knob 712 is then received onto threaded portion 724. A threaded portion of another adjustment knob 712 is passed through slot 780 of link 710 and threaded into bore 748. Another male adjustment knob is passed through bore 782 and threaded into bore 764 of cutting guide 708.

The location, amount, and shape of the portion of the tibia to be further resected will have been determined previously. The predetermined angular measurement is translated from the tibia to angular tibial resection guide 700 by the following procedure depicted in Figures 25 and 26. Proximal resection guide system 100 may have been used to size the tibial plateau, make the proximal tibial cut, and determine the thickness and geometry of a selected tibial augmentation wedge to be used. Once determined, lower edge 744 of the tibial surface reference 706 is slid onto slot 812 on reference block 714. Reference block 714 is selected for the appropriate condyle and tibial tray size. Cutting block 708 is then adjusted by loosening and tightening knobs 712 and by translating vertical link 710. Adjustment continues until cutting edge 760 of cutting block 708 is brought into contact with angular surface 818 on reference block 708. Thus, the correct angle for the chosen wedge resection has been translated thereby. Knobs 712 are then tightened to maintain the relationship between tibial surface reference 706 and cutting block 708. Resection guide 700, without reference block 714, is then used as a guide in tibial resection. Shaft 722 of stem member 704 is inserted into the threaded bushing of ATTT device 702 and rotated until the antirotation key present in platform 702 is seated into slot 732. Cutting block 708, in its prescribed orientation, is maneuvered as close as possible to the anterior surface of tibia 580.

As seen in Figure 27, cutting block 708 is then affixed to the anterior tibial surface with fixation spikes or drill bits 612. Knobs 712 are then loosened and the remainder of resection system 700 is then removed, leaving cutting block 708 affixed in place. The resection then proceeds with the surgeon resecting a pre-designated portion of tibia 580 by using - 23 -

surface 760 of cutting guide 708 as a guide as shown in Figure 28. After the further resection is completed, prosthesis 594 or some other prosthetic device may be installed on resected tibia 580. As depicted in Figure 29, wedge (augmentation member) 820 will be affixed over the further resected tibial area. Wedge 820 is generally triangular in vertical cross section. Member 822 is generally rectangular in cross section. Member 822 is used when the subsequent resection results in a similarly-shaped plurality of surfaces on tibia 580.

Components of the resection guide systems of the invention may be made from materials known to the art as capable of undergoing sterilization and possessing sufficient strength and rigidity for use, such as stainless steel and aluminum.

Because numerous modifications may be made of this invention without departing from the spirit thereof, the scope of the invention is not to be limited to the embodiments illustrated and described. Rather, the scope of the invention is to be determined by appended claims and their equivalents.

Claims

- 24 -WHAT IS CLAIMED IS:

1. A resecting guide system for enabling a surgeon to accurately measure and resect a portion of a bone proximate an articulating joint of a patient, the resection forming at least one planar surface for placing a replacement prosthesis thereon, the resecting guide system comprising: a cutting guide affixable to an exterior portion of the bone and including means for guiding the resection such that the resection results in the planar surface; means for aligning the cutting guide so that the planar surface will be generally perpendicular to an anatomical alignment feature of the patient; and means for vertically adjusting the cutting guide.

2. The resecting guide system of claim 1, the aligning means including an intramedullary alignment rod.

3. The resecting guide system of claim 1, the aligning means further including means for extramedullary alignment.

4. The resecting guide system of claim 3, the extramedullary aligning means including an extramedullary alignment rod.

5. The resecting guide system of claim 4, the extramedullary alignment rod including a telescoping section.

6. The resecting guide system of claim 3, the extramedullary aligning means including a light strip alignment device.

7. The resecting guide system of claim 1, further comprising means for determining a vertical location of the planar surface. - 25 -

8. The resecting guide system of claim 7, in which the vertical location determining means includes means for continuous vertical adjustment.

9. The resecting guide system of claim 8, in which the continuous vertical adjustment means includes a rack and pinion assembly.

10. The resecting guide system of claim 8, in which the continuous vertical adjustment means includes an advancing screw.

11. The resecting guide system of claim 8, the vertical dimension determining means being incremental and including a spring plunger cooperating with a vertical member with a plurality of bores defined therein, the plunger being biased in one of said bores.

12. The resecting guide system of claim 1, further comprising means for determining a distance between the cutting guide and a surface of the bone to be resected.

13. The resecting guide system of claim 12, in which the distance determining means includes a pivotable member disposable on the cutting guide.

14. The resecting guide system of claim 13, the distance determining means further including depth measuring means disposable proximate the pivotable member.

15. The resecting guide system of claim 14, the depth measuring means including a depressible element, the depressible element contacting the bone surface and including a scale for measuring said maximum distance. - 26 -

16. The resecting guide system of claim 15, in which the depressible element is biased away from the bone surface when the depth measuring means is disposed proximate the pivotable member.

17. The resecting guide system of claim 1, further comprising a surface reference with a reference edge for referencing a first resected planar surface, in which the cutting guide displays a cutting guide surface, and in which the cutting guide surface can be adjusted vertically and angularly with respect to the reference edge, the cutting guide surface being a guide for resecting a second planar surface.

18. The resecting guide system of claim 17, further comprising means for positioning said surface reference, said surface reference positioning means being disposable in an intramedullary canal and being detachably and adjustably connectable to said surface reference.

19. The resecting guide system of claim 17, further comprising means for transferring a bone measurement for resecting said second planar surface, said means determining the vertical and angular relation of the cutting guide surface relative to the reference edge.

20. The resecting guide of claim 19, in which said transferring means includes a reference block with reference surfaces.

21. The resecting guide system of claim 20, in which said reference surfaces include an angular surface and a slot, the angular surface being disposed against the cutting guide surface and a portion of the reference edge being disposed in the slot when the cutting guide is being vertically and angularly adjusted relative to the reference edge. - 27 -

22. The resecting guide system of claim 18, in which the cutting guide is detachable when the cutting guide surface is being used as a guide for resecting said second planar surface.

23. The resecting guide system of claim 1, in which the resection guiding means includes at lease one saw slot. 24. A method for accurately aligning a cutting guide on a bone proximate an articulating joint, the bone to be resected, the resection forming at least one planar surface for placing a replacement prosthesis thereon, the process comprising the steps of: providing a cutting guide with a cutting guide surface; disposing the cutting guide on the articulating surface, the cutting guide surface being oriented in a first vertical plane; positioning the cutting guide proximate the articulating surface; aligning the cutting guide; and affixing the cutting guide to the bone.

25. The method of claim 24, further comprising the step of determining a first distance from a reference edge to a point on the articulating surface.

26. The method of claim 25, further comprising the step of vertically aligning the cutting guide a second distance from the first vertical plane, the second distance including the first distance combined with a prosthesis thickness. WO 99/40864 _ ^ _^ PCT/US98/02819

AMENDED CLAIMS

[received by the International Bureau on 12 August 1998 (12.08.98); original claims 1-5, 7-10, 12 and 23-25 amended; remaining claims unchanged (5 pages)]

WHAT IS CLAIMED IS:

1. A resecting guide system for enabling a surgeon to accurately measure and resect a portion of a bone proximate an articulating joint of a patient, the resection forming at least one planar surface for placing a replacement prosthesis thereon, the resecting guide system comprising: a cutting guide affixable to an exterior portion of the bone and including means for guiding the resection such that the resection results in the planar surface; means for aligning the cutting guide being extendible bi- directionally distal from the articulating joint so that the planar surface will be generally perpendicular to an anatomical alignment feature of the patient; and means for vertically adjusting the cutting guide.

2. The resecting guide system of claim 1, the aligning means including an intramedullary alignment rod being extendible bi-directionally distal from the articulating joint.

3. The resecting guide system of claim 1, the aligning means further including means for extramedullary alignment extendible between one of the articulating joint and a first distal position, the articulating joint and a second distal position opposite said first distal position and the articulating joint and to both said first and second distal positions.

4. The resecting guide system of claim 3, the extramedullary aligning means including an extramedullary alignment rod intermediate between a first and second ends of said resecting guide system to enable alignment in one of a single direction and bi-direction distally from the articulating joint. - 29 -

5. The resecting guide system of claim 4, the extramedullary alignment rod including a telescoping section bi-directionally extendible simultaneously and retractable in one of a distal and proximal direction from the articulating joint.

7. The resecting guide system of claim 1, further comprising means for determining a vertical location of the planar surface relative to a reference point at one of a bi-directional location distally located from the articulating joint.

8. The resecting guide system of claim 7, in which the vertical location determining means includes means for bi-directionally continuous vertical adjustment.

9. The resecting guide system of claim 8, in which the bi-directionally continuous vertical adjustment means includes a rack and pinion assembly.

10. The resecting guide system of claim 8, in which the bi-directionally continuous vertical adjustment means includes an advancing screw.

12. The resecting guide system of claim 1, further comprising probe means for determining a distance between the cutting guide and a surface of the bone to be resected. - 30 -

15. The resecting guide system of claim 14, the depth measuring means including a depressible element, the depressible element contacting the bone surface and including a scale for measuring said maximum distance.

19. The resecting guide system of claim 17, further comprising means for transferring a bone measurement for resecting said second planar surface, - 31 -

said means determining the vertical and angular relation of the cutting guide surface relative to the reference edge.

21. The resecting guide system of claim 20, in which said reference surfaces include an angular surface and a slot, the angular surface being disposed against the cutting guide surface and a portion of the reference edge being disposed in the slot when the cutting guide is being vertically and angularly adjusted relative to the reference edge.

23. The resecting guide system of claim 1, in which the resection guiding means includes at lease one saw slot being angularly adjustable to match the planar surface at the articulating joint.

24. A method for accurately aligning a cutting guide on a bone proximate an articulating joint, the bone to be resected, the resection forming at least one planar surface for placing a replacement prosthesis thereon, the process comprising the steps of: providing a cutting guide with a cutting guide surface; disposing the cutting guide on the articulating surface, the cutting guide surface being oriented in a first vertical plane; positioning the cutting guide proximate the articulating surface; aligning the cutting guide by extending distally from the articulating joint in one of single and bi-directional adjustment; and affixing the cutting guide to the bone. - 32 -

25. The method of claim 24, further comprising the step of determining a first distance from a reference edge to a point on the articulating surface wherein said reference edge is located at a point extending bi-directionally away from said articulating joint.

26. The method of claim 25, further comprising the step of vertically aligning the cutting guide a second distance from the first vertical plane, the second distance including the first distance combined with a prosthesis thickness.