Devices and methods for unicondylar tibial implants

Abstract

To provide a device and method for unicondylar tibial implants.SOLUTION: A tibial implant cutting guide comprises a plate to engage a resected surface, and an elongate slot extending through the plate along an axis, the elongate slot having first and second longitudinal walls extending parallel to the axis, and a first end wall perpendicular to the axis, the first and second longitudinal walls are spaced apart by a prescribed distance and the width of the first end wall is at least as wide as the distance. A method of arthroplasty comprises: resecting a tibia to form a resected surface; advancing a cutting head in a cutting slot to engage flush with a flat first end of the cutting slot to form a bone channel; and inserting a keel into the bone channel. A method of manufacturing a tibial template comprises forming a longitudinal cutting slot in a plate and forming a widening of the cutting slot at an end of the cutting slot.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates generally, but not by way of limitation, to devices and methods for use in knee arthroplasty, such as total or partial knee replacement procedures. More specifically, but not by way of limitation, the disclosed devices and methods can be used to perform slot cutting within a resected bone surface. [Background technology]

[0002] The knee joint includes a femur with two distal convex condyles that engage with two concave condyles located at the proximal end of the tibia. Each condyle's pairing can form a compartment within the knee joint. Osteoarthritis can develop in the knee joint, where the cartilage in the knee joint begins to deteriorate and eventually fails, leading to bone-on-bone contact and potentially pain. Osteoarthritis can develop in one or both compartments. Total knee replacement is the most common surgical treatment for osteoarthritis and involves replacing the articular surfaces of the femur and tibia in both compartments. Partial knee replacement involves replacing the articular surfaces in only one compartment of the knee joint, leaving all of the surfaces and ligaments in the other compartment intact. Partial knee replacement can also act preventatively to reduce the incidence of disease in the other compartment. Partial knee replacements can be more surgically demanding due to the possibility of having to perform additional bony revisions and the ability to preserve all of the ligaments. Partial knee replacements can be referred to as unicompartmental or unicompartmental knee replacements.

[0003] A femoral or tibial component to be implanted into bone can benefit from a predetermined fixation scheme relative to the modified bone surface. To this end, the prosthetic component often includes one or more bone-engaging elements, such as anchors, extensions, keels, stems, fins, and the like, for penetrating into the bone material to facilitate fixation of the prosthetic component to the bone. The bone-engaging elements can be inserted into bone cavities that may be created in the resected bone surface. For example, holes, holes, slots, channels, and the like can be formed by drilling, chiseling, reaming, broaching, burring, and the like.

[0004] Some tibial components utilize a keel, which is an elongated projection extending from the base of the tibial plate. The projection extends generally parallel to the anterior-posterior axis of the component. To enhance the efficacy of the desired prosthetic implant and provide a desired user outcome, it is advantageous for the surfaces and edges of the prosthetic implant to match the surfaces and edges of the modified bone in a desired manner. As such, there remains a need for instruments used for revision that provide accurate (e.g., at a desired location) and precise (e.g., repeatable) bone revision.

[0005] Examples of unicondylar or partial knee replacement systems are described in U.S. Patent No. 6,277,949 to Goodfellow et al., entitled "Tibial prosthetic component for a partial or unicondylar bearing knee replacement, method of selecting such a tibial prosthetic component, method of implanting such a tibial prosthetic component and a kit for a surgeon," U.S. Patent No. 6,277,949 to Dodd et al., entitled "Prosthesis with fixed or mobile bearing," and U.S. Patent No. 6,277,949 to O'connor et al., entitled "Unicompartmental tibial components." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2011 / 110865 [Patent Document 2] International Publication No. 2015 / 155505 [Patent Document 3] International Publication No. 2022 / 148964 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have recognized, among other things, that a problem to be solved by traditional partial knee arthroplasty involves inserting a keel into a bone slot formed in the resected surface of the proximal tibia. It is desirable for the keel to fit securely and precisely within the bone slot in the proper location. Specifically, the width of the slot is desirably wide enough to allow the keel to fit in a press-fit manner for cementless applications, locking the keel in place. Furthermore, it can be advantageous for the keel to be precisely positioned in the anterior-posterior direction for a number of reasons. For example, the tibial component should be substantially aligned with the femoral component of the femur. Furthermore, the present inventors have recognized that imprecise positioning of the keel in the anterior-posterior direction can result in undesirable contact between the keel and the cortical bone wall of the tibia. Specifically, the posterior end of the keel contacts the cortical bone wall and creates undesirable stresses within the cortical bone wall. In extreme cases, the stresses can lead to fracture.

[0008] The inventors also recognize that precise positioning of the tibial keel in the anterior-posterior direction can be difficult due to the interaction of the cutting device with the cutting guide slot. For example, the inventors recognize that a typical cutting guide slot includes a longitudinal slot that extends in the anterior-posterior direction and has rounded ends. For example, the machining process used to form the cutting guide slot can result in curvatures at the ends of the slot that resemble fillets. These curved surfaces can interfere with a cutting device, such as a reciprocating saw blade head, inserted therein, thereby resulting in imprecise positioning of the slot. [Means for solving the problem]

[0009] The present subject matter can provide a solution to these and other problems, for example, by providing a cutting guide slot having end faces that are at 90 degrees relative to the walls of the main longitudinal slot. The end faces of the cutting guide slot can be formed by machining a short vertical slot at the end of the longitudinal slot. The short vertical slot can form a T-shaped end at the end of the longitudinal slot. The T-shaped end can form an end face at 90 degrees relative to the longitudinal slot, which allows the cutting head of a reciprocating saw blade to engage flush with the end of the slot, thereby creating a repeatable cutting action. Specifically, a reciprocating toothbrush saw can have front and rear end faces that engage with the T-shaped end slot. Thus, the saw blade head can travel further forward and backward without interference from the curved surface of the end with a radius of curvature.

[0010] In one aspect, a cutting guide for a tibial implant can include a plate configured to engage a resected surface of a tibia and an elongated slot extending through the plate along a slot axis, the elongated slot including a first longitudinal wall extending parallel to the slot axis, a second longitudinal wall extending parallel to the slot axis, and a first end wall that is flat and extends perpendicular to the slot axis, the first longitudinal wall being spaced apart from the second longitudinal wall by a predetermined distance, and the first end wall having a width at least equal to the predetermined distance.

[0011] In another aspect, a method of implanting a tibial tray in a knee arthroplasty may include resecting a proximal end of the tibia to form a proximal resection surface, positioning a plate on top of the proximal resection surface, the plate including a cutting slot, positioning a cutting head through the cutting slot, advancing the cutting head in a first direction to flush engage with the flat first end of the cutting slot to form a first end of a bone channel, and positioning the tibial tray over the proximal resection surface to insert a keel into the bone channel.

[0012] In a further aspect, a method of manufacturing a tibial template for knee arthroplasty may include providing a tibial plate, forming a longitudinally cut slot in the tibial plate, forming a first widening of the longitudinal cut slot at a first end of the longitudinal cut slot, and forming a second widening of the longitudinal cut slot at a second end of the longitudinal cut slot. [Brief explanation of the drawings]

[0013] [Figure 1A] FIG. 1A is a perspective view of a knee joint in flexion having a unicompartmental prosthetic device implanted therein. [Figure 1B] FIG. 1B is a side view of the knee joint of FIG. 1A in extension. [Figure 2A] FIG. 2A is a perspective view of the knee joint of FIGS. 1A and 1B showing vertical and horizontal resections in the proximal end of the tibia. [Figure 2B] FIG. 2B is a front view of the knee joint of FIGS. 1A and 1B showing vertical and horizontal resections in the proximal end of the tibia. [Figure 2C] Figure 2C is a schematic side view of the tibial component of the unicompartmental prosthetic device of Figures 1A and 1B implanted within the resected tibial surface of Figures 2A and 2B to illustrate the relative position between the keel and the cortical bone wall. [Figure 3] FIG. 3 is a perspective view of a unicondylar tibial implant of the present disclosure with a keel. [Figure 4] FIG. 4 is a bottom view of the unicondylar tibial implant of FIG. 4 showing the location of the keel between the anterior and posterior ends of the plate. [Figure 5] FIG. 5 is a side view of the unicondylar tibial implant of FIG. [Figure 6] FIG. 6 is a front view of the unicondylar tibial implant of FIG. [Figure 7] FIG. 7 is a perspective view of a tibial template of the present disclosure including cutting slots with widened ends. [Figure 8] 8 is a side view of the tibial template of FIG. 7. FIG. [Figure 9] 9 is a top view of the tibial template of FIG. 7. FIG. [Figure 10] 10 is a perspective view of a reciprocating saw blade of the present disclosure configured to interact with the cutting slot of FIG. 7; [Figure 11] 11 is a side view of a cutting head for the reciprocating saw blade of FIG. 10. FIG. [Figure 12] FIG. 12 is a top view of the cutting head of FIG. [Figure 13] FIG. 13 is a front view showing the cutting head of FIG. [Figure 14] 14 is a schematic side view of the reciprocating saw blade of FIG. 10 seated within the tibial template of FIG. [Figure 15A] FIG. 15A is a schematic illustration of a tibial template of the present disclosure illustrating the use of a machining tool to form cutting slots. [Figure 15B] FIG. 15B is a schematic view of the tibial template of FIG. 15A showing a reciprocating saw blade within the cutting slot. [Figure 16A] FIG. 16A is a schematic illustration of a tibial template of the present disclosure illustrating the formation of T-shaped end slots using a machining tool. [Figure 16B] FIG. 16B is a schematic view of the tibial template of FIG. 16A showing a reciprocating saw blade within the cutting slot. [Figure 17]FIG. 17 is an enlarged top view of a cutting slot of the present disclosure showing the dimensions of the cutting slot and the widened end. [Figure 18] FIG. 18 is a block diagram illustrating the operations of a method for forming a bone slot in the tibia for receiving the keel of a tibial implant. [Figure 19] FIG. 19 is a block diagram showing the operations of a method for creating cutting slots in a tibial template. DETAILED DESCRIPTION OF THE INVENTION

[0014] Figure 1A is a perspective view of a knee joint 10 in flexion with a unicompartmental prosthetic device 12 implanted therein. Figure 1B is a side view of the knee joint 10 of Figure 1A in extension. Figures 1A and 1B will be discussed simultaneously.

[0015] The knee joint 10 can include a femur 14 and a tibia 16. The unicompartmental prosthetic device 12 can include a femoral component 18 and a tibial component 20. The tibial component 20 can include a bearing insert 22.

[0016] The unicondylar prosthetic device 12 can be configured to replace only one condyle of the femur 14 and only one condyle of the tibia 16. The tibial component 20 can include a tray configured to receive a bearing insert 22. The tibial component 20 can include a plate 24 and a wall 26 for engaging the resected bone surface, as described with reference to FIGS. 2A and 2B. The plate 24 and wall 26 can include orthogonally arranged planar surfaces for engaging the bearing insert 22. The bearing insert 22 can include a concave articulating surface for receiving the femoral component 18. The femoral component 18 can include a concave articulating surface for rotation against the bearing insert 22.

[0017] The wall 26's flush medial-lateral engagement with the vertically resected bone surface of the tibia 16 and the plate 24's anterior-posterior positioning on the horizontally resected bone surface of the tibia 16 between the anterior and posterior cortical bone walls can facilitate desired alignment of the tibial component 20.

[0018] Figure 2A is a perspective view of the knee joint 10 of Figures 1A and 1B showing a bone modification 50 including a horizontal resection surface 52 and a vertical resection surface 54 at the proximal end of the tibia 16. Figure 2B is a front view of the knee joint 10 of Figures 1A and 1B showing the horizontal resection surface 52 and the vertical resection surface 54 at the proximal end of the tibia 16. Figures 2A and 2B will be discussed simultaneously.

[0019] Once implanted, the plate 24 (FIG. 1A) of the tibial component 20 can be positioned in a medial-lateral direction on the horizontal resection surface 52 so that the wall 26 engages the vertical resection surface 54. Additionally, the tibial component 20 can be positioned in an anterior-posterior direction so that the plate 24 rests on the horizontal resection surface 52 relative to the anterior and posterior cortical bone, as discussed with reference to FIG.

[0020] Ultimate placement of the tibial component 20 on the tibia 16 can be determined by forming the bone channel 56 by positioning a tibial template, such as the tibial template 200 of FIG. 7, in engagement with the horizontal resection surface 52 and the vertical resection surface 54. The surgeon can slide the tibial template 200 in a medial-lateral direction to engage the vertical resection surface 54, and then slide the tibial template 200 in an anterior-posterior direction to position the cutting slot for the keel between the anterior and posterior cortical walls. Using their skill and experience, the surgeon can position the tibial template 200 so that the cutting slot for the keel is located in a position that will provide the desired outcome for the patient.

[0021] FIG. 2C is a schematic side view of the tibial component 20 of the unicondylar prosthetic device 12 of FIGS. 1A and 1B implanted within the horizontal resection surface 52 to illustrate the relative positioning between the keel 28 and the cortical bone material 30. The bottom surface 32 of the plate 24 of the tibial component 20 can be positioned on top of the horizontal resection surface 52. To facilitate support of loads applied to the tibial component 20 from the femur 14 (FIG. 1A), it may be desirable for the plate 24 to rest on the cortical bone material 30 in an anterior-posterior position. The keel 28 can be pressed into the cancellous bone material 34 between the cortical bone material 30 below the horizontal resection surface 52. To avoid the formation of stress concentrations on the tibia 16, it may be advantageous for the keel 28 to be positioned between the anterior and posterior portions of the cortical bone material 30. Specifically, it may be desirable to ensure that the keel 28 is positioned sufficiently anterior to the posterior cortex 36 to prevent undesirable loads from being applied to the tibia 16. The present disclosure allows a tibial template to be formed to provide accurate placement of the keel 28 on the horizontal resection surface 52 to avoid undesirable outcomes for the patient.

[0022] FIG. 3 is a perspective view of a unicondylar tibial implant 100 of the present disclosure having a base plate 102 and a keel 104. FIG. 4 is a bottom view of the unicondylar tibial implant 100 of FIG. 4, illustrating the position of the keel 104 along the base plate 102 in the anterior-posterior direction. FIG. 5 is a side view of the unicondylar tibial implant 100 of FIG. 4. FIG. 6 is a front view of the unicondylar tibial implant 100 of FIG. 4. FIGS. 3-6 will be discussed simultaneously. In some embodiments, the unicondylar tibial implant 100 can include the tibial component 20 of FIGS. 1A, 1B, and 2C.

[0023] The base plate 102 may include a bearing surface 106, a bone-engaging surface 108, and an upstanding wall 110. The base plate 102 may further include a leading end 112, a medial side 114, a posterior end 116, and a lateral side 118. The upstanding wall 110 may have a surface 120 and a surface 122. The keel 104 may include a base 130 adjacent the bone-engaging surface 108 and a tip 132 distal from the base 130. The keel 104 may also include an inner wall 134 and an outer wall 136.

[0024] The baseplate 102 can be configured to replace the articular surface of a patient's tibia, such as the tibia 16 in FIG. 1A. FIGS. 3-6 illustrate a medial tibial bearing surface. The present disclosure is applicable to both medial and lateral bearing surfaces. A lateral tibial component can include a mirror image of the component shown in FIG. 3. In the illustrated embodiment, the baseplate 102 is generally C-shaped. In embodiments, the baseplate 102 can have a variety of shapes and can be, for example, generally rounded or oval. The shapes of the baseplate 102 at the anterior end 112, medial end 114, and posterior end 116 can be configured to approximate the shapes of the posterior and anterior lateral surfaces, respectively, of the tibial condyle. For example, the anterior end 112, medial end 114, and posterior end 116 can be configured to approximate the outer surface of the cortical bone material 30 in FIG. 2C.

[0025] The base plate 102 can be mounted such that, when the component is mounted, the bone-engaging surface 108 rests on the surface of the tibia, e.g., on the horizontal resection surface 52 in FIG. 2A . A surface 120 of the upstanding wall 110 can be configured to abut the central tibial eminence of the tibia, e.g., on the vertical resection surface 54 in FIG. 2A , when the component is mounted. A surface 122 of the upstanding wall 110 can be configured to abut a bearing component, e.g., the bearing insert 22 in FIG. 1A . The upstanding wall 110 can extend upward from the bearing surface 106 of the base plate 102 in a direction normal to the plane of the base plate 102.

[0026] Once attached, the bearing surface 106 replaces the tibial bearing surface of the anatomical tibia. The bearing surface 106 can be shaped to cooperate directly with the condyle of the patient's femur or a prosthetic replacement component, or with a bearing component positioned between the unicondylar tibial implant 100 and the anatomical femur or a femoral replacement component. In some embodiments, the bearing surface 106 can be convex in both the anterior-posterior and lateral-medial directions if the unicondylar tibial implant 100 is for the lateral condyle. In some embodiments, the bearing surface 106 can be flat or concave if the unicondylar tibial implant 100 is for the medial condyle. In some embodiments, the base plate 102 can be substantially flat and have a contour shaped to mimic the natural shape of the head of the tibia. The bone-engaging surface 108 of the base plate 102 can be configured to be secured to the proximal end of the tibia.

[0027] A medial-lateral width W of the base plate 102 is defined between the medial side 114 and the lateral side 118. A longitudinal anterior-posterior axis AA may extend between the leading end 112 and the trailing end 116. The keel 104 may extend along the longitudinal anterior-posterior axis AA. In some embodiments, the longitudinal anterior-posterior axis AA may be located approximately one-third of the width of the plate (i.e., 1 / 3W) from the lateral side 118 and defines a longitudinal axis length L of the base plate 102.

[0028] Primary fixation of the base plate 102 can be provided by the keel 104. Fixation is important for maintaining the unicondylar tibial implant 100 in a fixed state after implantation, as secondary fixation is achieved by allowing bone material to grow into and attach to the bone-engaging surface 108 and the keel 104. The keel 104 can protrude distally from the bone-engaging surface 108. The keel 104 can include an elongated projection having a length in the anterior-posterior direction and a width in the medial-lateral direction. The length can be greater than the width. The keel 104 can protrude distally from the bone-engaging surface 108 perpendicular to the bone-engaging surface 108. The keel 104 can extend longitudinally in a direction generally parallel to the lateral side 118 of the base plate 102. In other embodiments, the keel 104 can protrude distally at an angle relative to the bone-engaging surface 108.

[0029] In some embodiments, the keel 104 may include a solid or continuous body between the medial wall 134 and the lateral wall 136, as shown. Such a configuration may be intended for use in a cementless procedure. In some embodiments, a cementless version of the keel 104 may be configured to be force-fit into a slot formed in the bone material of the tibia. In some embodiments, the keel 104 may include a slot, such as slot 38 shown in FIG. 2C, between the medial wall 134 and the lateral wall 136 to receive bone cement and / or bone ingrowth. Cemented or cementless keels may or may not have through holes or slots within the keel. Cementless components may include a porous coating to encourage bone ingrowth.

[0030] The keel 104 may be centered on the bone-engaging surface 108 relative to the anterior-posterior axis AA. Specifically, the keels 104 may be spaced apart so that the distance d1 between the leading edge 138 of the keel 104 and the leading end 112 of the baseplate 102 is approximately the same as the distance d2 between the trailing edge 140 of the keel 104 and the trailing end 116 of the baseplate 102. In the illustrated embodiment, the keel 104 is not centered relative to the width W of the baseplate 102. The keel 104 may be positioned approximately 1 / 3 W from the lateral side 118. In some embodiments, the keel 104 may be positioned at other medial-lateral locations. For example, the region of the baseplate 102 from which the keel 104 extends may be positioned in the medial-most half of the baseplate 102, closest to the intercondylar eminence.

[0031] Typical dimensions of the base plate 102 may include an AP axis length L=44.92 mm, a keel length=25.92 mm, d1=d2=9.50 mm, and a keel distance from the lateral side=1 / 3 W=7.98 mm. In some embodiments, the thickness X (FIG. 6) of the keel 104 may be approximately 3 mm. In some embodiments, the thickness X may be 2.0 mm + / - 0.1 mm, or 1.5 mm + / - 0.1 mm, or 2.5 mm + / - 0.1 mm. In some embodiments, the thickness X may be between 2.4 mm and 1.7 mm, or between 1.9 mm and 1.5 mm.

[0032] As previously discussed, it is important that the keel 104 be positioned to avoid contact with cortical bone. The surgeon can determine the anterior-posterior location of the keel 104 by placing a tibial template 200 (FIG. 7) on the horizontal resection surface 52. The tibial template 200 disclosed herein can ensure that the keel 28 (FIG. 2C) is positioned where intended by the surgeon by providing cutting slots that allow for a precise, repeatable cutting process.

[0033] Figure 7 is a perspective view of a tibial template 200 of the present disclosure including a plate 202 and cutting slots 204. Figure 8 is a side view of the tibial template 200 of Figure 7. Figure 9 is a top view of the tibial template of Figure 7. Figures 7, 8, and 9 will be discussed simultaneously.

[0034] The plate 202 can include a bearing surface 206, a bone-engaging surface 208, and an upstanding wall 210. The plate 202 can further include a leading end 212, a medial side 214, a posterior end 216, and a lateral side 218. The upstanding wall 210 can include a surface 220 and a surface 222. The cutting slot 204 has an elongated portion 230 and widened ends 232A and 232B. The cutting slot 204 can be disposed within a groove 234. The groove 234 can include first and second rails 235A and 235B, a leading pocket 236A, and a posterior pocket 236B. The plate 202 can additionally include a first hole 237A and a second hole 237B.

[0035] As best seen in FIG. 9 , the elongated portion 230 can include a first longitudinal wall 238A and a second longitudinal wall 238B, the flared end 232A can include a leading end wall 240A, and the flared end 232B can include a trailing end wall 240B. An arcuate wall 242A can connect the first longitudinal wall 238A to the leading end wall 240A. An arcuate wall 244A can connect the second longitudinal wall 238B to the leading end wall 240A. An arcuate wall 242B can connect the first longitudinal wall 238A to the trailing end wall 240B. An arcuate wall 244B can connect the second longitudinal wall 238B to the trailing end wall 240B. In some embodiments, the front end wall 240A and the rear end wall 24B may be disposed at 90 degrees relative to the first longitudinal wall 238A and the second longitudinal wall 238B. In some embodiments, the front end wall 240A and the rear end wall 24B may be centered on the axis AB.

[0036] The tibial template 200 can be formed to approximate the size and shape of the base plate 102 and upstanding wall 110 of the unicondylar tibial implant 100 (FIGS. 3-6). As such, the bearing surface 206, bone-engaging surface 208, upstanding wall 210, anterior end 212, medial end 214, posterior end 216, lateral end 218, surface 220, surface 222 can be formed to be the same or substantially the same as the bearing surface 106, bone-engaging surface 108, upstanding wall 110, anterior end 112, medial end 114, posterior end 116, lateral end 118, surface 120, surface 122. However, it may be advantageous for the bearing surface 206 to be formed as a flat or planar surface to facilitate the inclusion of the cutting slots 204 and grooves 234.

[0037] The first longitudinal wall 238A and the second longitudinal wall 238B can extend linearly and parallel to each other along the front-rear axis AB. The first longitudinal wall 238A and the second longitudinal wall 238B can extend consistently to the widened ends 232A and 232B. The front end wall 240A and the rear end wall 240B can extend linearly and parallel to each other perpendicular to the front-rear axis AB. The front end wall 240A can have a predetermined width relative to the front-rear axis AB, which is at least as wide as the distance between the first longitudinal wall 238A and the second longitudinal wall 238B, e.g., width W1 in FIG. 17 . Thus, when first longitudinal wall 238A and second longitudinal wall 238B are extended forward and rearward, they intersect with first longitudinal wall 238A and second longitudinal wall 238B. In embodiments, arcuate wall 242A, arcuate wall 242B, arcuate wall 244A, and arcuate wall 244B may include semicircles. Thus, for example, when first longitudinal wall 238A is extended forward, first longitudinal wall 238A intersects with both ends of the semicircle of arcuate wall 242A. 9, so that short segments of flat walls can connect arcuate wall 242A with first longitudinal wall 238A and leading end wall 240A, and arcuate wall 244A with second longitudinal wall 238B and leading end wall 240A, respectively. In embodiments, arcuate wall 242A, arcuate wall 242B, arcuate wall 244A, and arcuate wall 244B can have curved shapes other than semicircular.

[0038] The tibial template 200 can be used to determine a location for the keel 104 within the horizontal resection surface 52 ( FIG. 1A ) and to form a slot within the horizontal resection surface 52 for the keel. Specifically, the surgeon can position the cutting slot 204 at a desired location on the horizontal resection surface 52 and then insert a cutting tool, such as the reciprocating saw blade 300 of FIG. 10 , into the cutting slot 204. In this manner, the surgeon can position the anterior end of the plate 202 adjacent to the anterior portion of the horizontal resection surface 52 and the posterior end of the plate 202 adjacent to the posterior portion of the horizontal resection surface 52. One or both of the first hole 237A and the second hole 237B can be used to fixate the tibial template 200 to the tibia, for example, by inserting a pin or nail therethrough into the bone material.

[0039] As discussed in more detail below, cutting slot 204 and groove 234 cooperate to receive reciprocating saw blade 300, FIG. 10. Enlarged ends 232A, 232B include flat rear and front faces and leading end walls 240A, 240B, respectively, to allow reciprocating saw blade 300 to travel fully forward and backward, thereby forming a bone slot or channel. The bone slot or channel has flat or planar rear and front faces and a precise length that allows keel 104 (FIG. 3) to be positioned fully forward or backward, depending on surgeon placement and other factors.

[0040] FIG. 10 is a perspective view of a reciprocating saw blade 300 of the present disclosure configured to interact with the cutting slot 204 of FIG. 7. The reciprocating saw blade 300 may include a cutting head 302, a shaft 304, and a coupler 306. The cutting head 302 may include a tip 308, a shoulder 310, a first blade 312A, and a second blade 312B. The first blade 312A may include a first plate portion 314A and a plurality of first teeth 316A. The second blade 312B may include a second plate portion 314B and a plurality of second teeth 316B. FIG. 11 is a side view of the cutting head 302 for the reciprocating saw blade 300 of FIG. 10. FIG. 12 is a top view of the cutting head 302 of FIG. 10. FIG. 13 is a front view of the cutting head 302 of FIG. 10. Figures 10 to 12 will be discussed simultaneously.

[0041] The coupler 306 can be configured to connect to a power source, such as a hand tool. In some embodiments, the coupler 306 can be configured to connect to a reciprocating mechanism of a reciprocating power tool. In some embodiments, the coupler 306 can include a flat portion having a notch 322 to which a clamping mechanism or chuck of the power tool can be attached. A shaft 304 can extend from the coupler 306 and can allow the cutting head 302 to be extended into an anatomy, such as a knee joint, to perform a cutting operation. The reciprocating saw blade 300 can be fabricated from a rigid material, such as stainless steel, to facilitate the transfer of reciprocating input power to the cutting head 302 while minimizing bending, vibration, and the like.

[0042] The shoulder 310 may include a base from which the first blade 312A and the second blade 312B extend. The first plate portion 314A and the second plate portion 314B may extend parallel to each other and perpendicular to the shoulder 310. The first plate portion 314A may include a planar end surface 318A and a planar end surface 320A. The second plate portion 314B may include a planar end surface 318B and a planar end surface 320B. The first plate portion 314A and the second plate portion 314B may extend parallel to each other. The first plate portion 314A and the second plate portion 314B may have a height H ( FIG. 13 ) above the shoulder 310. The first plate portion 314A and the second plate portion 314B can be spaced apart from one another such that their outer, e.g., outwardly facing, surfaces can be spaced apart from one another by a distance D (FIG. 13). In some embodiments, the distance D can be equal to the thickness X of the keel 104 (FIG. 6). The first and second teeth 316A, 316B can be formed to extend distally from the shoulder 310 by a predetermined amount. This amount can be designed to fit the keel 104.

[0043] The reciprocating saw blade 300 can be configured to engage the cutting slot 204 and groove 234 (FIG. 7) to form a linear slot or channel. As discussed in more detail with reference to FIG. 14, the length of the slot can be created consistently within the horizontal cutting surface 52 (FIG. 2A).

[0044] FIG. 14 is a schematic side view of the reciprocating saw blade 300 of FIG. 10 seated within the tibial template 200 of FIG. 7. The reciprocating saw blade 300 can interact with the tibial template 200 to control movement of the cutting head 302 relative to the plate 202. The reciprocating saw blade 300 can be configured to approach the tibial template 200 from the anterior direction, so that the cutting head 302 extends past the anterior end 212 toward the posterior end 216. The shoulder 310 can be configured to fit within the groove 234 so that the shoulder 310 can ride on the first and second rails 235A and 235B that are parallel to the first and second blades 312A and 312B. The tip 308 can seat on top of the posterior pocket 236B, and the shoulder 310 can extend along the anterior pocket 236A. Rear pocket 236B can be axially longer than tip 308 to allow cutting head 302 to travel fully rearward, so that planar end surfaces 318A and 318B engage rear end wall 240B. Shaft 304 can extend from shoulder 310 through front pocket 236A. First teeth 316A and second teeth 316B extend through plate 202, so that first plate portion 314A and second plate portion 314B engage the walls of cutting slot 204.

[0045] The first plate portion 314A can extend along the first longitudinal wall 238A. The second plate portion 314B can extend along the second longitudinal wall 238B. As the cutting head 302 is reciprocated, the planar end surfaces 318A and 318B can face and flush engage the trailing end wall 240B. As the cutting head is reciprocated, the planar end surfaces 320A and 320B can face and flush engage the leading end wall 240A. As discussed with reference to FIGS. 15B and 16B , the planar end surfaces 318B can flush engage the trailing end wall 240B to enable the cutting head 302 to consistently cut a slot into the bone material without interference, e.g., sticking, between the cutting head 302 and the cutting slot 204.

[0046] FIG. 15A is a schematic diagram of the tibial template 200 showing the machining tool 350 within the elongated portion 320 of the cutting slot 204. The tibial template 200 can include a plate 202 through which the cutting slot 204 extends. The cutting slot 204 can extend along an axis and can have a first longitudinal wall 238A and a second longitudinal wall 238B. However, unlike the present disclosure, the first longitudinal wall 238A and the second longitudinal wall 238B can be connected by an arcuate end wall 360. FIG. 15A illustrates an example of an operation in forming the cutting slot 204. The elongated portion 320 has been fabricated, but the widened ends 232A and 232B have not yet been formed. While FIG. 15A shows only one end of the cutting slot 204, the opposite end can be formed in a similar manner.

[0047] The machining tool 350 can include milling cutters, including circular cutting bodies such as ball-nose end mill cutters, square end mill cutters, radius end mill cutters, corner radius end mill cutters, and the like. Because these milling cutters can have a circular cutting profile, as shown in FIG. 15A , the milling cutters typically produce only straight, flat, or planar surfaces when moved along their axes. As such, the first longitudinal wall 238A and the second longitudinal wall 238B can be formed by moving the machining tool 350 along one or more paths parallel to the cutting slot 204. However, when the machining tool 350 reaches the end of the cutting slot 204, it can produce an arcuate end wall 360 instead of a flat wall.

[0048] FIG. 15B is a schematic diagram of the tibial template 200 of FIG. 15A , showing the cutting head 302 within the cutting slot 204. FIG. 15B can illustrate a hypothetical engagement of the cutting head 302 with the elongated portion 320 prior to the formation of the widened ends 232A and 232B. Due to the presence of the arcuate end wall 360, the cutting head 302 is prevented from reaching the farthest end of the cutting slot 204 by a distance S. The arcuate end wall 360 prevents the planar end surface 318B of the cutting head 302 from advancing completely to the right (with respect to the orientation of FIG. 15B ) a distance equal to the distance S. The inventors have recognized that the presence of the distance S can have adverse consequences for the placement of the keel 104 ( FIG. 3 ) within the horizontal resection surface 52 ( FIG. 2A ). For example, the presence of the arcuate end wall 360 at the posterior end of the cutting slot 204 can result in the keel 104 being positioned too far forward. Similarly, the presence of an arcuate end wall, similar to arcuate end wall 360, at the anterior end of cutting slot 204 may result in keel 104 being positioned too far posteriorly. As such, variations in the actual placement of the bone channel or bone slot (e.g., bone channel 56 in FIG. 2A) formed by cutting head 302 due to the curved end wall may result in the keel being too close to or in contact with the posterior cortex of the tibia. This may impose undesirable stresses on the bone material, which may, in extreme cases, result in fracture of the bone material.

[0049] FIG. 16A is a schematic diagram of the tibial template 200 of the present disclosure showing a machining tool 350 within the cutting slot 204 of the present disclosure. The first longitudinal wall 238A and the second longitudinal wall 238B can be formed by moving the machining tool 350 along one or more paths parallel to the cutting slot 204, as shown in FIG. 15A. However, when the machining tool 350 reaches the end of the cutting slot 204, an arcuate end wall can be generated, similar to the arcuate end wall 360 of FIG. 15A. However, instead of leaving the arcuate end wall in the finished product, the widened end 232B can be formed by moving the machining tool 350 along an additional path. Note also that the widened end 232A ( FIG. 9 ) is fabricated by the same process as the widened end 232B. The widened end 232B can be formed by moving the machining tool 350 one or more times along a path perpendicular to the elongated portion 230 and the axis AB. The machining tool 350 can be moved along the axis AC. In some embodiments, moving the machining tool 350 along the axis AC can position the rear end wall 240B where the apex of the arcuate end wall 360 is located. As such, the overall longitudinal length of the cutting slot 204 in FIGS. 15A and 16A can be the same. However, in further embodiments, FIG. 15A can represent an intermediate step in forming the overall longitudinal length of the cutting slot 204, where the cutting slot 204 can be extended or lengthened from that formed in FIG. 15A by forming one or both of the widened ends 232A and 232B. FIG. 16A illustrates one example of an operation in forming the cutting slot 204, where the elongated portion 320 and the widened ends 232A and 232B are formed.

[0050] FIG. 16B is a schematic diagram of the tibial template 200 of FIG. 16A , showing the cutting head 302 within the cutting slot 204. The posterior end wall 240B can allow the planar end face 318B of the cutting head 302 to be advanced completely to the right (with respect to the orientation of FIG. 16B ), i.e., the posterior end wall 240B and the cutting head 302 are engaged flush. Compared to FIG. 15B , the cutting head 302 can be advanced a predetermined distance to the right by an amount equal to the distance S. As such, the keel 104 can be positioned within the cut bone slot at a location selected by the surgeon, e.g., a location to avoid contact with cortical bone. Furthermore, the width of the cutting head 302, e.g., distance D in FIG. 13 , is irrelevant to the anterior-posterior formation of the bone channel (bone channel 56 in FIG. 2A ) because the anterior and posterior end walls 240A, 240B, and the cutting slot 204 are flat. For example, if one were to use a cutting head narrower than cutting head 302, such a cutting head may advance further forward or backward in the case of a cutting slot with a radius of curvature (similar to that shown in FIG. 15A) because the edge with a radius of curvature would have less impact on the narrow cutting head. The present disclosure can eliminate this variable from the bone channel formation process.

[0051] FIG. 17 is an enlarged top view of the cutting slot 204 of the present disclosure, showing the dimensions of the narrowed portion 230 and the widened end 232B. The narrowed portion 230 can have a width W1. The widened end 232B can have an overall length L1, a flat length L2, and a width W2. L1 is greater than L2. In some embodiments, L2 can be equal to or greater than W1. The flat length L2 can be equal to or greater than the distance D ( FIG. 13 ) between the outside of the first plate portion 314A and the outside of the second plate portion 314B. The length L1 can be sufficiently large to generate the flat length L2 to be equal to or greater than the width W1. The length L1 can be determined based on the cutting diameter of the machining tool 350. For example, the difference between L1 and L2 may be equal to the diameter of the machining tool 350, with half the diameter on each side of the flat length L2. However, L1 may be a length greater than the length of L2 plus the diameter of the machining tool 350.

[0052] 18 is a block diagram illustrating operations of a method 500 for forming a slot in bone for the keel 104 of a unicondylar tibial implant 100. Although discussed with reference to a unicondylar tibial implant 100 and a tibial template 200, the method 500 can include the use of similarly formed devices. The method 500 can additionally include more or fewer operations other than steps 502 through 518. Additionally, in other embodiments, steps 502 through 518 can be performed in other orders.

[0053] In step 502, the tibial template 200 can be positioned on the horizontal resection surface 52. The surgeon can position the tibial template on the horizontal resection surface of the tibia. The tibial template is designed to approximate the size and shape of the base plate of the tibial implant and includes a cutting slot with an enlarged end to accommodate a saw blade.

[0054] In step 504, the tibial template 200 can be engaged with the tibial eminence formed in the vertical resection surface 54. The tibial template can be slid along the horizontal resection surface to engage the vertical resection surface, thereby positioning the tibial template in a medial-lateral direction.

[0055] In step 506, the tibial template 200 can be slid in an anterior-posterior direction along the horizontal resection surface 52 until the cutting slot 204 is located in a desired position. For example, the tibial template can be slid so that its anterior end is aligned with the anterior cortical wall, or the tibial template can be slid so that its posterior end is aligned with the posterior cortical wall. In some embodiments, the cutting slot 204 can be positioned between the anterior and posterior cortical walls.

[0056] In step 508, the tibial template 200 can be fixed on the horizontal resection surface 52 by inserting pins into the tibial template 200, for example, at the first hole 237A or the second hole 237B. Fixing the tibial template in place on the horizontal resection surface ensures that the template does not move during the cutting process. This can be done by inserting pins through the template and into the bone material of the tibia. The pins can prevent anterior-posterior movement of the tibial template and can wedge the tibial template against the tibial eminence.

[0057] In step 510, the cutting head 302 of the reciprocating saw blade 300 can be inserted into the cutting slot 204. A reciprocating saw blade specifically designed to interact with the tibial template can be inserted into the cutting slot. The saw blade can have a cutting head with a shoulder formed to engage with a rail parallel to the cutting slot and a blade with teeth formed to extend through the tibial template to cut bone material. The blades can be spaced apart to match the width of the keel and cutting slot. The blade can have a flat end face for engaging the flat end wall at the widened end of the cutting slot.

[0058] At step 512, cutting head 302 may be engaged with flared ends 232A and 232B. Specifically, planar end surfaces 318A and 318B may be engaged with trailing end wall 240B, and planar end surfaces 320A and 320B may be engaged with leading end wall 240A. The surgeon may move cutting head 302 to engage planar end surfaces 318A and 318B.

[0059] In step 514, the cutting head 302 can be reciprocated within the cutting slot 204, for example, by a power tool attached to the coupler 306. Additionally, a user or operator of the reciprocating saw blade 300 can move the cutting head 302 within the cutting slot 204 in a so-called dolphin pattern, e.g., along a sine wave, while the power tool reciprocates the cutting head 302. The width of the cutting slot within the bone can be determined by the distance between the longitudinal walls of the cutting slot, and the length of the cutting slot within the bone can be controlled by engagement of the saw blade with the flat end wall of the widened end. While the power tool reciprocates the cutting head 302 back and forth microscopically, the cutting head 302 can simultaneously be moved back and forth macroscopically by the surgeon. Thus, the reciprocating motion from the power tool may provide the bone cutting action, while the surgeon may form a bone channel, such as bone channel 56 in Figure 2A, by engaging cutting head 302 with planar end surface 318A and planar end surface 318B. In some embodiments, steps 512 and 514 may be performed simultaneously.

[0060] At step 516, the keel 104 of the unicondylar tibial implant 100 may be positioned within the channel or slot formed by the first plurality of teeth 316A and the second plurality of teeth 316B of the cutting head 302. The surgeon may position the keel 104 in a desired location for positioning the unicondylar tibial implant 100 on the tibia 16, thereby providing support from the cortical bone material 30 and aligning with the femoral component 18. Additionally, the surgeon may position the keel 104 so that it does not contact the cortical bone material 30.

[0061] In step 518, the unicondylar tibial implant 100 can be moved within the channel or slot formed by the cutting head 302, for example, so that the leading edge 138 of the keel 104 engages the leading end of the channel or slot formed by the cutting head 302. To ensure that the keel 104 is not engaged with the cortical bone material 30 in one direction, the surgeon can push the keel 104 to engage the end of the bone slot in the opposite direction. Step 518 can be optional. For example, the keel 104 can be positioned so that it is located between the ends of the bone slot formed by the cutting slot 204.

[0062] 19 is a block diagram illustrating steps in a method 550 for forming cutting slots 204 in a tibial template 200. Although discussed with reference to a tibial template 200, the method 550 may include the use of similarly formed devices. The method 550 may additionally include more or fewer operations other than steps 552 through 554. Additionally, in other embodiments, steps 552 through 554 may be performed in other orders.

[0063] In step 552, the elongated portion 230 may be formed in the plate 202 of the tibial template 200. The elongated portion 230 may be formed by moving a milling tool, such as a machining tool 350, along the axis AB. The plate 202 may be held in place in a fixture or jig. The elongated portion 230 may be formed to have a length at least as long as the keel 104.

[0064] In step 554, widened ends 232A and 232B may be formed at the ends of thin portion 230. Widened ends 232A and 232B may be formed by moving a milling tool, such as machining tool 350, perpendicular to thin portion 320, such as along axis AC in FIG. 16A. Widened ends 232A and 232B may increase the length of thin portion 230 formed in step 552, or the ends of thin portion 230 may simply be widened.

[0065] As discussed herein, it can be difficult to achieve flush engagement of the cutting head of a toothbrush-type cutting blade with the end of a slot. Typically, a radius of curvature exists at the corners of the slot, a result of the machining process, e.g., the milling process. Here, a rotary cutting bit with a radius of curvature is used to create the elongated slot. This radius of curvature can be problematic because the saw blade can bind within the corners of the guide slot. Therefore, the precise placement of the bone channel created with the cutting head can vary from procedure to procedure, even using the same template and cutting head. The present disclosure allows for the use of cutting slots with T-shaped ends, allowing the cutting head to advance to repeatable positions without interference from the cutting slot, e.g., without binding with the radius of curvature at each corner. The T-shape allows for a controllable and repeatable process to be performed, so that the bone channel is ultimately created where the surgeon intended. For example, the T-shape can allow for the creation of a 90-degree cut by allowing the front and rear faces of the cutting head, located above the cutting teeth, to impact the slot. As such, the bone channel can be positioned where intended by the surgeon, away from the cortical bone material, specifically on the posterior side, thereby reducing the risk of breakage. Furthermore, with the present disclosure, the width of the cutting head, e.g., distance D in FIG. 13, is irrelevant to the anterior-posterior formation of the bone channel because the flat end of the cutting slot is flat. Therefore, the present disclosure can eliminate this variable from the bone channel formation process.

[0066] (Example) Example 1 is a cutting guide for a tibial implant, the cutting guide including a plate formed to engage with the resected surface of the tibia and an elongated slot extending through the plate along a slot axis, the elongated slot including a first longitudinal wall extending parallel to the slot axis, a second longitudinal wall extending parallel to the slot axis, and a first end wall that is flat and extends perpendicular to the slot axis, the first longitudinal wall being spaced apart from the second longitudinal wall by a predetermined distance, and the width of the first end wall being at least as great as the predetermined distance.

[0067] In Example 2, the problem of Example 1 optionally includes the first end wall forming a portion of a first widened end of the elongated slot, the first widened end having a length greater than a predetermined distance.

[0068] In Example 3, the problems of any one or more of Examples 1 to 2 optionally include that the first widened end of the elongated slot includes a first T-shaped end of the elongated slot.

[0069] In Example 4, the object of Example 3 optionally includes the first T-shaped end being centered over the elongated slot.

[0070] In Example 5, the problems of any one or more of Examples 3 to 4 optionally include a second T-shaped end of the elongated slot, the second T-shaped end including a second end wall disposed perpendicular to the first longitudinal wall and the second longitudinal wall.

[0071] In Example 6, the subject matter of Example 5 optionally includes, wherein the elongated slot includes a predetermined length, and the predetermined length is greater than a predetermined distance.

[0072] In Example 7, the problems of any one or more of Examples 5 to 6 optionally include: the first T-shaped end of the elongated slot includes a first arcuate end connecting the first longitudinal wall and the first end wall of the elongated slot and a second arcuate end connecting the second longitudinal wall and the first end wall of the elongated slot; and the second T-shaped end of the elongated slot includes a third arcuate end connecting the second longitudinal wall and the second end wall of the elongated slot and a fourth arcuate end connecting the second longitudinal wall and the second end wall of the elongated slot.

[0073] In Example 8, the problems of any one or more of Examples 5 to 7 optionally include the elongated slot, the first T-shaped end, and the second T-shaped end being disposed within a groove in the plate.

[0074] In Example 9, the problem of Example 8 optionally includes that the groove includes a rear pocket disposed at the rear of the elongated slot, a front pocket disposed at the front of the elongated slot, and a pair of rails extending parallel to each other on opposite sides of the elongated slot.

[0075] In Example 10, the subject of Example 9 optionally includes the anterior pocket extending through the periphery of the plate.

[0076] In Example 11, the subject matter of any one or more of Examples 1 through 10 optionally includes one or more holes extending through the plate for receiving anchor pins.

[0077] In Example 12, the problems of any one or more of Examples 1 to 11 optionally include the plate including a tibial template for partial knee arthroplasty, and the plate including an upstanding vertical wall extending perpendicular to the plate.

[0078] In Example 13, the problem of Example 12 optionally includes that the plate includes a straight edge having an upstanding vertical wall extending along the straight edge, and a curved edge opposite the straight edge that is positioned to approximate the curvature of the tibia.

[0079] Example 14 is a method of implanting a tibial tray in knee arthroplasty, the method including: resecting a proximal end of the tibia to form a proximal resection surface; positioning a plate on top of the proximal resection surface, the plate including a cutting slot; positioning a cutting head through the cutting slot; advancing the cutting head in a first direction to engage flush with the flat first end of the cutting slot to form a first end of a bone channel; and positioning the tibial tray on the proximal resection surface to insert a keel into the bone channel.

[0080] In Example 15, the problem of Example 14 optionally includes advancing the cutting head in a second direction opposite the first direction to flush engage with the flat second end of the cutting slot to form a second end of the bone channel.

[0081] In Example 16, the problem of Example 15 optionally includes positioning a keel between the first and second ends of the bone channel to avoid contact with the cortical bone wall.

[0082] In Example 17, the object of any one or more of Examples 15-16 optionally includes extending pins through the plate to immobilize the plate on the proximal resection surface.

[0083] Example 18 is a method of manufacturing a tibial template for knee arthroplasty, the method including providing a tibial plate, forming a longitudinally cut slot in the tibial plate, forming a first widening of the longitudinally cut slot at a first end of the longitudinally cut slot, and forming a second widening of the longitudinally cut slot at a second end of the longitudinally cut slot.

[0084] In Example 19, the problem of Example 18 optionally relates to the following: forming the longitudinal cutting slot in the tibial plate includes moving the rotary machining tool along a cutting axis to form opposing longitudinal surfaces; forming a first widened portion of the longitudinal cutting slot at a first end of the longitudinal cutting slot includes moving the rotary machining tool along a first axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal cutting slot; and forming a second widened portion of the longitudinal cutting slot at the first end of the longitudinal cutting slot includes moving the rotary machining tool along a second axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal cutting slot.

[0085] In Example 20, the problem of Example 19 optionally includes the steps of: moving the rotary machining tool along a first axis perpendicular to the cutting axis intersecting the opposing longitudinal surfaces of the longitudinal cutting slot; removing a first rounded surface at a first end of the longitudinal cutting slot formed by the rotary machining tool; and moving the rotary machining tool along a second axis perpendicular to the cutting axis intersecting the opposing longitudinal surfaces of the longitudinal cutting slot; removing a second rounded surface at a second end of the longitudinal cutting slot formed by the rotary machining tool.

[0086] Each of these non-limiting examples can stand alone by itself or can be combined in various permutations or combinations with one or more of the other examples.

[0087] Miscellaneous notes The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "embodiments." Such embodiments may include elements in addition to those shown or described. However, the inventors also contemplate embodiments in which only the elements shown or described are provided. Furthermore, the inventors also contemplate embodiments using combinations or permutations of the illustrated and described elements (or one or more aspects thereof) with respect to the specific embodiment (or one or more aspects thereof) shown or described, or with respect to other embodiments (or one or more aspects thereof).

[0088] In the event of a conflicting usage between this document and any document so incorporated by reference, the document in this document will control.

[0089] In this document, the terms "a" or "an" are used to include one or more than one, as is common in patent documents, independently of any other instance or usage of "at least one" or "one or more." In this document, the term "or" means a non-exclusive or, whereby "A or B" is used to include "A but not B," "B but not A," and "A and B," unless otherwise specified. In this document, the terms "including" and "in which" are used as plain English equivalents of the terms "comprising" and "wherein," respectively. Also, in the claims below, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, or processes that include elements in addition to those listed after such terms in a claim are still considered to be within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc., are used merely as labels and do not impose numerical requirements on their objects.

[0090] The method embodiments described herein can be at least partially machine or computer-implemented. Some embodiments can include a computer-readable or machine-readable medium. Such a medium is encoded with instructions operable to configure an electronic device to perform the methods described in the embodiments. An implementation of such a method can include code, such as microcode, assembly language code, high-level language code, or the like. Such code can include computer-readable instructions for performing various methods. The code may form part of a computer program product. Further, in one example, the code can be tangibly stored, for example, during execution or at other times, on one or more volatile, non-transitory, or non-volatile tangible computer-readable media. Examples of these tangible computer-readable media include hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memory (RAM), read-only memory (ROM), and the like.

[0091] The above description is intended to be illustrative, not limiting. For example, the above examples (or one or more aspects thereof) can be used in combination with each other. Other embodiments may be utilized, for example, by those skilled in the art, upon review of the above description. The Abstract is provided to comply with U.S.C. § 1.72(b) to enable the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, the grouping of various features in the above Detailed Description serves to simplify the disclosure. This should not be construed as intending that a non-claimed feature is essential to any claim. Rather, subject matter lies in less than all features of a particular disclosed embodiment. Accordingly, the following claims are herein incorporated into the Detailed Description as examples or embodiments. Each claim stands on its own as a separate embodiment, and such embodiments can be combined with each other in various combinations or permutations. The scope of the present invention should be determined by reference to the appended claims, along with the full range of equivalents to which such claims are entitled.

Claims

1. 1. A cutting guide for a tibial implant, said cutting guide comprising: a plate configured to engage the resected surface of the tibia; an elongated slot extending through the plate along a slot axis; Including, The elongated slot is a first longitudinal wall extending parallel to the slot axis; a second longitudinal wall extending parallel to the slot axis; a first end wall that is flat and extends perpendicular to the slot axis; Including, the first longitudinal wall is spaced a predetermined distance from the second longitudinal wall; the width of the first end wall is at least as great as the predetermined distance; Cutting guide for tibial implants.

2. The cutting guide of claim 1 , wherein the first end wall forms a portion of a first widened end of the elongated slot, the first widened end having a length greater than the predetermined distance.

3. The cutting guide of claim 1 , wherein the first enlarged end of the elongated slot comprises a first T-shaped end of the elongated slot.

4. The cutting guide of claim 3 , wherein said first T-shaped end is centered over said elongated slot.

5. 4. The cutting guide of claim 3, further comprising a second T-shaped end of the elongated slot, the second T-shaped end including a second end wall disposed perpendicular to the first longitudinal wall and the second longitudinal wall.

6. The cutting guide of claim 5 , wherein the elongated slot includes a predetermined length, the predetermined length being greater than the predetermined distance.

7. The first T-shaped end of the elongated slot comprises: a first arcuate end joining the first longitudinal wall and the first end wall of the elongated slot; a second arcuate end joining the second longitudinal wall and the first end wall of the elongated slot; The second T-shaped end of the elongated slot comprises: a third arcuate end joining the second longitudinal wall and the second end wall of the elongated slot; a fourth arcuate end joining the second longitudinal wall and the second end wall of the elongated slot. The cutting guide according to claim 5 .

8. The cutting guide of claim 5 , wherein the first T-shaped end and the second T-shaped end are disposed within grooves in the plate.

9. The groove is a rear pocket located at a rear portion of the elongated slot; a front pocket located in front of the elongated slot; a pair of rails extending parallel to each other on opposite sides of the elongated slot; The cutting guide of claim 8 , comprising:

10. The cutting guide of claim 9 , wherein the anterior pocket extends through the periphery of the plate.

11. The cutting guide of claim 1 , further comprising one or more holes extending through the plate for receiving anchor pins.

12. The cutting guide of claim 1 , wherein the plate comprises a tibial template for partial knee arthroplasty, the plate including an upstanding vertical wall extending perpendicular to the plate.

13. The plate is a straight edge along which the upstanding vertical wall extends; The cutting guide of claim 12 , including a curved edge opposite the straight edge, the curved edge being oriented to approximate the curvature of the tibia.

14. 1. A method of implanting a tibial tray in a knee arthroplasty, the method comprising: resecting the proximal end of the tibia to form a proximal resection surface; positioning a plate over the proximal resection surface, the plate including a cutting slot; positioning a cutting head through the cutting slot; advancing the cutting head in a first direction to flush engage a flat first end of the cutting slot to form a first end of a bone channel; positioning the tibial tray over the proximal resection surface to insert a keel into the bone channel; A method for implanting a tibial tray in a knee arthroplasty, comprising:

15. 15. The method of claim 14, further comprising advancing the cutting head in a second direction opposite the first direction to flushly engage a flat second end of the cutting slot to form a second end of the bone channel.

16. The method of claim 15, further comprising positioning the keel between the first and second ends of the bone channel to avoid contact with a cortical bone wall.

17. The method of claim 15, further comprising extending pins through the plate to secure the plate over the proximal resection surface.

18. 1. A method of manufacturing a tibial template for knee arthroplasty, the method comprising: providing a tibial plate; forming a longitudinally cut slot in the tibial plate; forming a first widening of the longitudinally cut slot at a first end of the longitudinally cut slot; forming a second widening of the longitudinally cut slot at a second end of the longitudinally cut slot; 1. A method for manufacturing a tibial template for knee arthroplasty, comprising:

19. forming the longitudinal cutting slot within the tibial plate includes moving a rotary machining tool along a cutting axis to form opposing longitudinal surfaces; forming the first widening of the longitudinal-cutting slot at the first end of the longitudinal-cutting slot includes moving the rotary machining tool along a first axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal-cutting slot; forming a second widening of the longitudinal-cutting slot at the first end of the longitudinal-cutting slot includes moving the rotary machining tool along a second axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal-cutting slot.

20. The method of claim 18.

20. moving the rotary machining tool along the first axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal cutting slot includes removing a first radiused surface at the first end of the longitudinal cutting slot formed by the rotary machining tool; moving the rotary machining tool along the second axis perpendicular to the cutting axis that intersects the opposing longitudinal surfaces of the longitudinal cutting slot includes removing a second radiused surface at the second end of the longitudinal cutting slot formed by the rotary machining tool; 20. The method of claim 19.

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