Cut order biasing for robotic total knee arthroplasty

Abstract

A method to facilitate a robotic total knee arthroplasty includes performing a plurality of femoral cuts on a femur, the performing the plurality of femoral cuts including performing a distal femoral cut of the plurality of femoral cuts, performing an anterior femoral cut of the plurality of femoral cuts, performing an anterior chamfer cut of the plurality of femoral cuts after the performing the distal femoral cut and the performing the anterior femoral cut, and performing a posterior femoral cut of the plurality of femoral cuts after performing all other femoral cuts of the plurality of femoral cuts. The method further includes performing at least one tibial cut on a tibia after the performing the plurality of femoral cuts on the femur.

Description

Atty. Docket No. : 5247.033 A WOCUT ORDER BIASING FOR ROBOTIC TOTAL KNEE ARTHROPLASTYCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims benefit of priority of U.S. Provisional Patent Application No. 63 / 694,982, filed on September 16, 2024, and entitled "Cut Order Biasing For Robotic TKA” the disclosure of which is hereby incorporated herein by reference in its entirety.BACKGROUND

[0002] Aspects described herein relate, generally, to the field of surgery. More specifically, aspects relate to the field of robotic surgery and robot-assisted surgery. Even more specifically, aspects relate to the ordering of surgical cuts to be performed during resections of bone in a knee joint as part of a total knee arthroplasty. Aspects may also have utility in other procedures involving resection(s) of bone in joints.

[0003] Total Knee Arthroplasty (“TKA”), commonly referred to as a “knee replacement,” is a procedure of orthopedic surgery in which a knee joint, such as an arthritic knee joint, is replaced with a prosthesis. In a knee replacement, a series of bone resections are made to accommodate the placement of implants. Clinically, the order of cuts made to resect bone in a knee joint may be driven by factors such as surgeon preference and technological constraints, among other factors.SUMMARY

[0004] During performance of a TKA, blade skiving may negatively affect the accuracy, safety and / or efficiency of the various cuts made to resect bone. Blade skiving occurs when a cutting tool (e.g., a blade of a sagittal saw) attempts to enter or otherwise cut a rounded, slippery, and / or smooth surface, such as cartilage-covered surfaces of osteophytes, causing the blade to be redirected away from an intended entry point or area. Thus, a desire exists for technologies that minimize the occurrence and / or impacts of blade skiving, particularly in the case of robotic and robot-assisted surgeries.Atty. Docket No. : 5247.033 A WO

[0005] Another challenge of TKAs is resecting dense bone, such as dense femoral bone when shaping a femur to accommodate an implant. For example, the blade (e.g., of a sagittal saw) may become lodged or otherwise stuck within a cut being made in the dense bone. This may cause an operator and / or robot to have to “peck” at the bone by pulling and pushing the blade back and forth, which may negatively affect the accuracy, safety and / or efficiency of the various cuts made to resect bone. Thus, a desire exists for technologies that minimize the amount of dense bone that needs to be cut at one time.

[0006] TKAs may also compromise the stability of a knee joint, such as when forces are applied to the knee joint during various cuts performed during the procedure. Soft tissues between the tibia and femur may provide some stability to the knee to resist these forces, but these tissues may be damaged or destroyed early on during the procedure, which may negatively affect the accuracy, safety, and / or efficiency of the procedure. Thus, a desire exists for technologies that better maintain the natural stability of the knee during a TKA.

[0007] The present disclosure provides, in a first aspect, a method to facilitate a robotic total knee arthroplasty. The method includes performing a plurality of femoral cuts on a femur. The performing the plurality of femoral cuts includes performing a distal femoral cut of the plurality of femoral cuts and performing an anterior femoral cut of the plurality of femoral cuts. The performing the plurality of femoral cuts further includes performing an anterior chamfer cut of the plurality of femoral cuts after the performing the distal femoral cut and the performing the anterior femoral cut. The performing the plurality of femoral cuts may further include performing a posterior femoral cut of the plurality of femoral cuts after performing all other femoral cuts of the plurality of femoral cuts.

[0008] The present disclosure provides, in a second aspect, a method to facilitate a robotic total knee arthroplasty. The method includes performing a plurality of femoral cuts on a femur. The performing the plurality of femoral cuts on the femur includes performing a distal femoral cut of the plurality of femoral cuts and performing an anterior femoral cut of the plurality of femoral cuts. The performing the plurality ofAtty. Docket No. : 5247.033 A WO femoral cuts further includes performing an anterior chamfer cut of the plurality of femoral cuts after the performing the distal femoral cut and the performing the anterior femoral cut.

[0009] The present disclosure provides, in a third aspect, a method to facilitate a total knee arthroplasty. The method includes performing a plurality of femoral cuts. The performing the plurality of femoral cuts includes performing a posterior femoral cut of the plurality of femoral cuts after performing all other cuts of the plurality of femoral cuts. The method further includes performing a tibial cut on a tibia after the performing the plurality of femoral cuts.

[0010] The present disclosure provides, in embodiments, a computer system including a memory and a processing circuit in communication with the memory. The computer system may be configured to perform method(s) as disclosed herein.

[0011] The present disclosure provides, in embodiments, a computer program product including a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing method(s) as disclosed herein.

[0012] In one or more embodiments, the performing the plurality of femoral cuts on the femur further includes performing the distal femoral cut before performing the anterior femoral cut. In one or more embodiments, the performing the plurality of femoral cuts on the femur further includes performing the anterior femoral cut before performing the distal femoral cut.

[0013] In one or more embodiments, the performing the distal femoral cut and the performing the anterior femoral cut further include reducing an amount of bone in a plane of a cut path of the anterior chamfer cut.

[0014] In one or more embodiments, the performing the distal femoral cut further includes removing femoral material from a distal portion of the femur such that a substantially planar bone surface is formed on a distal portion of the femur, whichAtty. Docket No. : 5247.033 A WO facilitates penetration of an anterior chamfer portion of the femur by a cutting tool when performing the anterior chamfer cut.

[0015] In one or more embodiments, the performing the anterior chamfer cut further includes cutting the anterior chamfer portion of the femur with the cutting tool. The cutting tool commences cutting along a cut path of the anterior chamfer cut through the substantially planar bone surface.

[0016] In one or more embodiments, the performing the anterior femoral cut further includes removing femoral material from an anterior portion of the femur such that a substantially planar bone surface is formed on an anterior portion of the femur, which facilitates penetration of an anterior chamfer portion of the femur by a cutting tool when performing the anterior chamfer cut.

[0017] In one or more embodiments, the performing the anterior chamfer cut further includes cutting the anterior chamfer portion of the femur with the cutting tool. The cutting tool commences cutting along a cut path of the of the anterior chamfer cut through the substantially planar bone surface.

[0018] In one or more embodiments, the method further includes fixing a robotic cutting tool relative to the femur without use of external fixation pins. The robotic cutting tool is to be used in performing at least one femoral cut of the plurality of femoral cuts.

[0019] In one or more embodiments, the method further includes maintaining a natural anatomic tensioning between the femur and the tibia at least until the performing the posterior femoral cut.

[0020] In one or more embodiments, the method further includes press-fitting an uncemented, press-fit implant to the femur.

[0021] In one or more embodiments, the performing the plurality of femoral cuts further includes performing a posterior chamfer cut of the plurality of femoral cuts as a last femoral cut performed as part of the robotic total knee arthroplasty.Atty. Docket No. : 5247.033 A WO

[0022] These, and other objects, features and advantages of this disclosure will become apparent from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Aspects of the disclosure are particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. Features and advantages of the disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings in which:

[0024] FIG. 1 depicts a knee joint prior to bone resections performed as part of a TKA, in accordance with an aspect of the present disclosure;

[0025] FIG. 2 depicts the knee joint of FIG. 1 following a resection of a distal portion of a femur of the knee joint, in accordance with an aspect of the present disclosure;

[0026] FIG. 3 depicts the knee joint of FIG. 1 following a resection of an anterior portion of the femur, in accordance with an aspect of the present disclosure;

[0027] FIG. 4 depicts the knee joint of FIG. 1 following the resection of the distal portion and the resection of the anterior portion, in accordance with an aspect of the present disclosure;

[0028] FIG. 5 depicts the knee joint of FIG. 4 following a resection of an anterior chamfer portion of the femur, in accordance with an aspect of the present disclosure;

[0029] FIG. 6 depicts the knee joint of FIG. 5 following a resection of a posterior chamfer portion of the femur, in accordance with an aspect of the present disclosure;

[0030] FIG. 7 depicts the knee joint of FIG. 6 following a resection of a posterior portion of the femur, in accordance with an aspect of the present disclosure;Atty. Docket No. : 5247.033 A WO

[0031] FIG. 8 depicts the knee joint of FIG. 7 following a resection of a tibial portion of a tibia of the knee joint, in accordance with an aspect of the present disclosure;

[0032] FIG. 9 depicts a computer-generated model of a patient’s femur showing a cutting plane and / or path of an anterior chamfer cut following a resection of an anterior portion of the femur, in accordance with an aspect of the present disclosure;

[0033] FIG. 10 depicts a computer-generated model of a patient’s femur showing a cutting plane and / or path of an anterior chamfer cut following resections of an anterior portion of the femur and a distal portion of the femur, in accordance with an aspect of the present disclosure;

[0034] FIG. 11 depicts an example process for biasing cut ordering of a TKA, in accordance with an aspect of the present disclosure;

[0035] FIG. 12 depicts an example process for performing femoral cuts on a femur, in accordance with an aspect of the present disclosure; and

[0036] FIG. 13 depicts an example computer system to incorporate, use, and / or facilitate aspects described herein.DETAILED DESCRIPTION

[0037] Aspects are discussed herein with reference to various exemplary embodiments and to the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, though those skilled in the art will recognize that various aspects may be practiced without these specific details. In other instances, well-known structures are not shown in detail to avoid unnecessary obscuring of aspects described.

[0038] Furthermore, there is no intention to be bound by any expressed or implied theory presented herein. It is also understood that specific devices and processes illustrated in the attached drawings, and described in the following specification, areAtty. Docket No. : 5247.033 A WO exemplary embodiments of inventive concepts described in the appended claims. Hence, specific dimensions and other physical characteristics of embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0039] Described herein are aspects (e.g., methods, systems, computer systems, computer program products) for describing and / or determining optimized cut orders for various cuts to be made in whole or in part by a surgeon and / or robot (e.g., a robot-mounted cutting tool or instrument of a robot) to a knee joint during a TKA. For example, aspects provide a novel approach to facilitate the cutting of dense bone and the maintenance of natural anatomic tensioning and / or stability of a knee joint during a TKA. For instance, aspects can incorporate and / or use known joint biomechanics to form a surgical resection plan that improves the accuracy, safety, and / or efficiency of manual and / or robotic (or robot-assisted) TKA cutting.

[0040] Robots and / or other computer integrated systems and / or equipment are increasingly utilized in surgical procedures. Often, such systems and / or devices include a mounted (e.g., robot-mounted) cutting tool to perform cuts, resections and / or incisions (cuts, resections and / or incisions may be referred to herein generally as “cuts”). In the example of active surgical systems, the cuts are controlled by a computer system and / or software program that dynamically directs the movement and other actions of the cutting tool by directing the robot to perform such actions (e.g., the robot is actively executing the cuts). In the example of semi-autonomous surgical systems, the cuts are user-initiated and at least partially controlled by the user - that is, a human operator (e.g., a surgeon) of the robot and / or robotic system dynamically directs, typically via physical input devices, the movement and other actions of the cutting tool by directing the robot to perform such actions, and a computer system and / or software program may assist the human operator by controlling various aspects of the robot. Commanding a robot to execute or assist with surgical cuts may require generating a cut path and / or toolpath for a robot with a mounted cutting instrument (e.g., a scalpel, sagittal saw, or other cutting tool) to follow. A cut path and / or toolpath represents a series of ordered coordinates through which an instrument, such as a cutting tool, is to travel and / or is constrained within when performing a function,Atty. Docket No. : 5247.033 A WO like cutting. For a surgical procedure such as a TKA, this may include planning or mapping a resection profile detailing an order of surgical cuts to be performed during the procedure. A resection profile may further detail, for example, a positioning and / or orientation of a robot and / or a cutting tool (or a blade thereof), among other details.

[0041] In fully robotic (e.g., active), robot-assisted, or manual TKAs, a surgeon may plan a resection profile, including a series of cut paths (e.g., toolpaths) along which a cutting tool is to travel to make various surgical cuts. Generating a resection profile may take into account various considerations, including general and patientspecific anatomical considerations (e.g., maintaining soft tissues which naturally tension the knee joint), clinical considerations such as kinematic alignment, the preferred referencing approach, and the need to make tool changes for the execution of certain cuts by a robot with a mounted cutting tool, among other considerations. A system incorporating aspects described herein may thus include a robot with a built-in computer system and / or a cutting instrument, or may be a computer system which may be combined with, or otherwise used to control, a robot (e.g., remotely). The computer system may include software or another computer program product directing the robot to perform aspects described herein. In embodiments, the system may also broadly include surgical personnel and standard surgical equipment, such as fixation means to fix the robot and / or the robot mounted cutting tool relative to the patient’s anatomy.

[0042] FIG. 1 depicts a knee joint prior to bone resections performed as part of a TKA, in accordance with aspects of the present disclosure. The knee joint is of a patient, and FIG. 1 depicts bones of the patient’s knee joint, including the femur 102, the tibia 104 and the patella 106, along with example cut paths, cuts and / or resections of the TKA. The resections generally include a plurality of planar cuts made to the patient’s femur 102, tibia 104 and / or patella 106. The plurality of planar cuts may in some embodiments include five femoral cuts (e.g., a distal femoral cut 110, an anterior femoral cut 112, an anterior chamfer cut 114, a posterior femoral cut 116, and a posterior chamfer cut 118) performed on the femur 102 of the knee joint, a tibial cut 120 performed on the tibia 104 of the knee joint, and / or a patellar cut 122 performedAtty. Docket No. : 5247.033 A WO on a patella 106 of the knee joint. In some embodiments, not all of the planar cuts may be performed, for example, the patellar cut 122 may be optional. All of these planar cuts may be performed and / or achieved with a cutting instrument (e.g., a robotmounted cutting instrument), such as a sagittal saw, rotary tool, laser, ultrasound, and / or reciprocating saw, among other instruments.

[0043] The planar cuts correspond to removal of femoral material (e.g., bone and / or cartilage) from the femur 102, removal of tibial material (e.g., bone and / or cartilage) from the tibia 104, and / or removal of patellar material (e.g., bone and / or cartilage) from the patella 106. In embodiments, the distal femoral cut 110 may correspond to a resection of a distal portion 102b of the femur 102 to form a substantially planar distal surface 124 (as shown in FIG. 2) on the femur 102. In embodiments, the anterior femoral cut 112 may correspond to a resection of an anterior portion 102a of the femur 102 to form a substantially planar anterior surface 126 (as shown in FIG. 3) on the femur 102. In embodiments, the posterior femoral cut 116 may correspond to a resection of a posterior portion 102e of the femur 102 to form a substantially planar posterior surface 132 (as shown in FIG. 7) on the femur 102. In embodiments, the anterior chamfer cut 114 may correspond to a resection of an anterior chamfer portion 102c of the femur 102, which may form a substantially planar anterior chamfer surface 128 (as shown in FIG. 5) on the femur 102. The substantially planar anterior chamfer surface 128 provides a chamfer between the substantially planar distal surface 124 and the substantially planar anterior surface 126. In embodiments, the posterior chamfer cut 118 may correspond to a resection of a posterior chamfer portion 102d of the femur 102, which may form a substantially planar posterior chamfer surface 130 on the femur 102. The substantially planar posterior chamfer surface 130 provides a chamfer between the substantially planar distal surface 124 and the substantially planar posterior surface 132. In embodiments, the tibial cut 120 may correspond to a resection of a tibial portion 104a of the tibia 104 (e.g., a portion of a proximal end of the tibia 104) to form a substantially planar tibial surface 134 on the tibia 104 (as shown in FIG. 8). In embodiments, the patellar cut 122 may correspond to a resection of a portion 106a of the patella 106, which may form a resurfaced patellar surface 136 (as shown in FIG. 8) on the patella 106.Atty. Docket No. : 5247.033 A WO

[0044] One aspect of the knee joint which may be of particular importance to aspects of the present disclosure is a space 108 that exists between the femur 104 and the tibia 104, e.g., between the posterior portion 102e of the femur 102 and the tibial portion 104a of the tibia 104 when the knee joint is in flexion, as shown in FIG. 1, and between the distal portion 102b of the femur and the tibial portion 104a of the tibia 104 when the knee joint is in extension. Specifically, the space 108 may include a variety of soft tissues (e.g., medial meniscus, lateral meniscus, cruciate ligaments, etc.) (not shown) that anatomically tension the femur 102 and the tibia 104 relative to each other. The space 108 may be of particular importance because connections of and / or between the femur 102 and the tibia 104, such as those formed by cartilage on articulating portions of the femur 102 and the tibia 104 that are ultimately resected, may be weakened and / or severed during a TKA. The loss of the soft tissues in the space 108, for instance loss caused from the resection of the posterior portion of the femur, may contribute to decreased stability of the knee joint during performance of the TKA.

[0045] Embodiments of aspects described herein provide a process for biasing cut ordering of a TKA. FIG. 11 depicts one example of such a process. Referring to FIG. 11, the process includes fixing 1110 a cutting tool relative to a patient’s knee joint (e.g., relative to the femur 102, the tibia 104, and / or the patella 106). In an example, the cutting tool may be a robot-mounted cutting tool, such as a sagittal saw (not shown). In embodiments, one or more fixation component(s) may be employed to fix the cutting tool. The fixation component(s) may include clamps, pins, or any other component s) that stabilize(s) the cutting tool relative to the knee joint or the bones thereof (e.g., relative to the femur 102, the tibia 104, and / or the patella 106) so as to allow a robot or surgeon to reliably guide the cutting tool during performance of the TKA, such as when performing one or more femoral cut(s), tibial cut(s) and / or patellar cut(s). As will be described in more detail below, aspects of the present disclosure may minimize, reduce or otherwise eliminate the need to use invasive means, such as invasive fixation pins, to fix the cutting tool.

[0046] In an aspect, the process of FIG. 11 further includes performing 1120 one or more (e.g., one or a plurality of) femoral cut(s) on the femur 102, for example, withAtty. Docket No. : 5247.033 A WO the cutting tool. In embodiments, the performing 1120 one or more femoral cut(s) may be achieved following the fixing 1110 of the cutting tool as described above. However, in some embodiments, and particularly those embodiments in which a manual surgery is performed, or in which part(s) of a TKA are performed manually, the cutting tool may not be fixed relative to the patient’s knee joint at all and may instead be guided solely by the operator (e.g., surgeon).

[0047] An initial cut made during the TKA, be it the distal femoral cut 110, the anterior femoral cut 112, or some other cut (e.g., the posterior chamfer cut 118), may be the most difficult cut to initiate due to the need for the cutting tool to penetrate a rounded and / or slippery (e.g., cartilage covered) surface of the femur 102. Attempting to penetrate a bone (e.g., the femur 102) at a rounded surface (e.g., of an osteophyte), or at a point that includes cartilage, may cause blade skiving of a blade of the cutting tool. Blade skiving may reduce the accuracy, efficiency and / or safety of the TKA, for example, by redirecting the blade toward tissue(s) not intended to be cut. or by contributing to the blade jamming during cutting. These and other problems associated with blade skiving may result in poor cut accuracy and may generally slow down the cutting during any resection(s), which increases surgical times. However, a cut on the femur 102 may form a substantially planar bone surface which may facilitate the subsequent performance of other cut(s) to the femur 102, and therefore it may be advantageous to deliberately order the plurality of femoral cuts accordingly. For instance, it might be advantageous to perform one cut to provide a flat surface into which the cutting tool may penetrate or otherwise enter the femur 102 to make another cut or other cuts.

[0048] FIG. 12 depicts an example process for performing femoral cuts on a femur, in accordance with an aspect of the present disclosure. FIG. 12 depicts a specific example of performing 1120 the one or more femoral cut(s) of FIG. 11. Specifically, FIG. 12 includes performing (1210) the distal femoral cut (e.g., 110) and the anterior femoral cut (e.g., 112). These two cuts could be performed in either order relative to each other. In embodiments, the distal femoral cut 110 may be performed before the anterior femoral cut 112, as shown by FIGS. 2 and 4. Performing 1210 the distal femoral cut 110 results in resection of the distal portion 102b of the femur 102 and theAtty. Docket No. : 5247.033 A WO formation of the substantially planar distal surface 124 on the femur 102. In other embodiments, the anterior femoral cut 112 may be performed before the distal femoral cut 110, as shown by FIGS. 3 and 4. Performing 1210 the anterior femoral cut 112 results in resection of the anterior portion 102a of the femur 102 and the formation of the substantially planar anterior surface 126 on the femur 102.

[0049] Depending on which of the distal femoral cut 110 and the anterior femoral cut 112 is performed before the other, the resulting substantially planar surface may facilitate performance of the remaining cut. For instance, if the distal femoral cut 110 is performed before the anterior femoral cut 112, then the substantially planar distal surface 124 resulting from the distal femoral cut 110 may facilitate performance of the anterior femoral cut 112, and if the anterior femoral cut 112 is performed before the distal femoral cut 110, the substantially planar anterior surface 126 resulting from the anterior femoral cut 112 may facilitate performance of the distal femoral cut 110, as shown by FIGS. 2-4. More specifically, performing the distal femoral cut 110 first as in FIG. 2 may provide the substantially planar distal surface 124 into which the cutting tool may enter to perform the anterior femoral cut 112. Alternatively, performing the anterior femoral cut 112 first as in FIG. 3 may provide the substantially planar anterior surface 126 into which the cutting tool may enter to perform the distal femoral cut 110. In addition, each of the substantially planar distal surface 124 and the substantially planar anterior surface 126 may provide a surface into which the cutting tool may enter to perform the anterior chamfer cut 114, as shown in FIGS. 4-5.

[0050] It may be particularly useful during an autonomous or semi-autonomous TKA to perform the distal femoral cut 110 before the anterior femoral cut 112 so as to account for the potential scenario in which the robotic-cutting tool (e.g., the system and / or robot controlling the robotic cutting tool) malfunctions or is otherwise insufficient to perform the TKA, resulting in the operator having to abort the autonomous or semi -autonomous surgery and perform any remaining cuts and / or bone resections fully manually. Specifically, the substantially planar distal surface 124 (resulting from the distal femoral cut 110) may advantageously provide a respective entry point for commencing each of one or more, or even all remaining, cuts of theAtty. Docket No. : 5247.033 A WO plurality of femoral cuts performed on the femur 102, as can be seen in FIG. 2. Thus, performing the distal femoral cut 110 before the anterior femoral cut 112 may allow for the cutting tool to make remaining cuts by entering the bone (e.g., the femur 102) at various entry points along the substantially planar distal surface 124. For instance, the anterior femoral cut, posterior femoral cut, anterior chamfer cut, and posterior chamfer cut can each be made beginning from a point on the substantially planar surface formed by the distal femoral cut. Thus, performing the distal femoral cut 110 before the anterior femoral cut 112 may increase at least the accuracy, safety and / or efficiency of the TKA by reducing, minimizing, or otherwise eliminating the risk of blade skiving that results from cutting a smooth or slippery bone surface.

[0051] However, in some embodiments it may alternatively be advantageous to perform 1120 the anterior femoral cut 112 before the distal femoral cut 110. In embodiments, such as in the case of an autonomous or semi -autonomous TKA, performance of the femoral cuts may include one or more tool changes, i.e., incorporation of a right-angle adapter at an extremity (e.g., an arm) of a robot. A tool change may be needed to facilitate performance of various different cuts during a TKA, for instance. In an example, the anterior femoral cut 112 may be performed before the distal femoral cut 110 to reduce the total number and / or type of tool changes required during the TKA, which may in turn improve at least the safety and / or efficiency of the procedure.

[0052] Continuing with FIG. 12, the process also includes performing 1220 the anterior chamfer cut 114 to resect the anterior chamfer portion 102c of the femur 102, as shown in FIG. 5. The process can perform the anterior chamfer cut 114 after performing the distal femoral cut 110 and the anterior femoral cut 112, as shown and as described above. In embodiments, the anterior chamfer portion 102c of the femur 102 may be relatively dense bone material (e.g., osseous tissue) (e.g., denser than the bone material of the anterior portion 102a and / or the distal portion 102b). In embodiments, the anterior chamfer portion 102c may represent the densest bone (e.g., the densest portion of the femur 102, the tibia 104, and / or the patella 106) to be cut during the TKA.Atty. Docket No. : 5247.033 A WO

[0053] Thus, the cutting of the anterior chamfer portion 102c of the femur during performance 1220 of the anterior chamfer cut 114 may be particularly difficult as compared to the performance of the distal femoral cut 110 and / or the anterior femoral cut 112 at 1210. Specifically, the cutting of the anterior chamfer portion 102c may be relatively time consuming and may further be more likely to result in the cutting tool (e.g., the blade of the cutting tool) becoming lodged or otherwise stuck in the femur 102 as compared to the cutting of the distal portion 102b and / or the anterior portion 102a, requiring dislodgment of the cutting tool, for instance, by pulling and / or pushing the blade backward and forward to “peck” at the bone.

[0054] Thus, in an aspect, the process reduces the potential for the cutting tool to become stuck or lodged in a cut path of the anterior chamfer cut 114 (e.g., in a space between the anterior chamfer portion 102c and the remaining bone of the femur 102), for example, by reducing the length of the anterior chamfer cut 114 and / or by reducing an amount of bone in a plane of a cut path of the anterior chamfer cut 114. In an example, the length of the anterior chamfer cut 114 may be reduced by first performing the distal femoral cut 110 and / or the anterior femoral cut 112 (at 1210) and then performing the anterior chamfer cut 114 (at 1220), as shown in FIGS. 2-5 and 9-10. In this way, the method may facilitate the cutting of relatively dense, and perhaps the densest, bone (e.g., the anterior chamfer portion 102c) of the femur 102 by reducing the distance the cutting tool must travel through the femur 102 in the anterior chamfer portion 102c thereof, and thereby reducing the amount of bone which must be resected during performance of the anterior chamfer cut 114.

[0055] Referring now to FIGS. 9 & 10, a computer-generated model of the femur 102 is shown and depicts a cut path (and a plane of the cut path) of the anterior chamfer cut 114 interposed over the femur 102. In FIG. 9, the substantially planar anterior surface 126 is shown following the resection of the anterior portion 102a of the femur 102 as described above, but prior to the resection of the distal portion 102b of the femur 102, and anterior chamfer portion 102c is shown corresponding to anterior chamfer cut 114. In FIG. 10, the substantially planar anterior surface 126 is shown following the resections of the anterior portion 102a and the distal portion 102b of the femur 102 as described above, and anterior chamfer portion 102c isAtty. Docket No. : 5247.033 A WO shown corresponding to anterior chamfer cut 114 in this scenario. It is seen based on a comparison of FIGS. 9 and 10 that the cut path of the anterior chamfer cut 114 is greatly reduced by the additional resection of the distal portion 102b as compared to the state of the femur 102 in FIG. 9. Said another way, the amount of bone of the anterior chamfer portion 102c that is in the plane of the cut path of the anterior chamfer cut 114 is greatly reduced by the resection of both the anterior portion 102a and the distal portion 102b of the femur 102 (as in the scenario of FIG. 10) prior to performing the anterior chamfer cut 114, as compared to the scenario of FIG. 9 where only the anterior portion 102a has been resected prior to performing the anterior chamfer cut 114. Of course, a surgeon could perform the anterior chamfer cut 114 without resecting either of the anterior portion 102a or the distal portion 102b, in which case the cut path of the anterior chamfer cut 114 would be even longer, and thus less desirable, than that of the scenarios shown in FIGS. 9-10.

[0056] Performance (1210) of the distal femoral cut 110 and / or the anterior femoral cut 112 prior to performance (1220) of the anterior chamfer cut 114 may also reduce, minimize and / or eliminate instances of blade skiving, as the cutting tool may be able to penetrate the femur 102 through the substantially planar distal surface 124 and / or the substantially planar anterior surface 126, as opposed to a rounded or slippery surface of the femur 102 (e.g., prior to performing the distal femoral cut 110 and / or the anterior femoral cut 112, as described above).

[0057] In an aspect, the process of FIG. 12 further includes performing 1230 the posterior chamfer cut 118, as shown in FIG. 6. The performing 1230 the posterior chamfer cut 118 results in a resection of the posterior chamfer portion 102d of the femur 102. Resecting the posterior chamfer portion 102d may form the substantially planar posterior chamfer surface 130 on the femur 102.

[0058] With reference to FIG. 6, performance of the posterior chamfer cut 118 may be achieved following performance of the distal femoral cut 110 and / or the anterior femoral cut 112 (at 1210). For example, performance of the posterior chamfer cut 118 may be achieved by the cutting tool commencing cutting by entering into the substantially planar distal surface 124 (e.g., after performing the distal femoral cutAtty. Docket No. : 5247.033 A WO110 at 1210). In embodiments, the process may perform the posterior chamfer cut 118 in any order relative to any one or more of the plurality of femoral cuts, including the anterior chamfer cut 114 and / or the anterior femoral cut 112. In embodiments, the posterior chamfer cut 118 may be the first cut performed during the performing 220 the femoral cut(s).

[0059] In one embodiment, the posterior chamfer cut 118 is performed at least prior to performing the posterior femoral cut 116, for example, to facilitate performing the posterior femoral cut and / or to maintain the natural anatomic tensioning of the knee joint via the soft tissues located in the space 108 for as long as possible during the TKA. In embodiments, performing the posterior chamfer cut 118 prior to performing the posterior femoral cut 116 may permit the cutting tool to commence cutting by entering into the substantially planar posterior chamfer surface 130 of the femur 102 during performing the posterior femoral cut 116, as opposed to having to enter into a rounded or cartilage covered surface of the femur 102. In this way, performing the posterior chamfer cut 118 prior to performing the posterior femoral cut 116 may increase the accuracy, efficiency and / or safety of the TKA. Additionally, performing the posterior chamfer cut 118 prior to performing the posterior femoral cut 116 may help maintain the natural anatomic tensioning of the knee joint, which provides additional advantages as described in more detail below.

[0060] Continuing with FIG. 12, the process further includes performing 1240 the posterior femoral cut 116, as shown in FIG. 7. Performing the posterior femoral cut 116 results in a resection of the posterior portion 102e of the femur 102 to form the substantially planar posterior surface 132 on the femur 102. In an embodiment, performing the posterior femoral cut 116 may be achieved at least following performing the distal femoral cut 110 and the anterior femoral cut 112, performing the anterior chamfer cut 114, and performing the posterior chamfer cut 118, as shown in FIG. 7. Said another way, the posterior femoral cut 116 may be the last or final cut made to the femur 102 during performance of the femoral cut(s) on the femur 102. Performing the posterior femoral cut 116 after all other femoral cuts may allow for the natural anatomic tensioning of the knee joint to be maintained throughout performance of the femoral cut(s), which may in turn improve at least the safety,Atty. Docket No. : 5247.033 A WO efficiency and / or accuracy of the TKA. In some embodiments, the posterior femoral cut 116 may also represent the penultimate (e.g., second to last) cut of the planar cuts to be performed during the TKA, as explained in more detail below.

[0061] Referring back to FIG. 11, the process further includes performing 1130 one or more tibial cut(s) 120 to the tibia 104. In embodiments, performing the one or more tibial cut(s) 120 results in a resection of the tibial portion 104a of the tibia 104, as shown in FIG. 8. In an embodiment, the one or more tibial cut(s) 120 is a single tibial cut. In other embodiments, the one or more tibial cut(s) 120 are a plurality of tibial cuts. For simplicity, the description of the one or more tibial cut(s) 120 as part of the method will proceed as if there is only a single tibial cut 120, but it should be understood by one of ordinary skill that the tibial cut 120 could also be a plurality of tibial cuts.

[0062] The posterior portion 102e of the femur 102 and the tibial portion 104a of the tibia 104 are generally located opposite each other about the space 108 between the femur 102 and the tibia 104 when the knee joint is in flexion, as shown in FIG. 1. In some TKAs, a surgeon may employ a resection plan in which either the posterior portion 102e or the tibial portion 104a are resected first (e.g., during a first cut to be performed on the femur 102 and tibia 104 of the knee joint as part of the TKA). However, there are soft tissues (not shown) that sit between and / or are connected to the posterior portion 102e and / or the tibial portion 104a. These tissues provide at least some natural tensioning to the knee joint, and may therefore stabilize the femur 102 relative to the tibia 104 during the TKA when they remain substantially intact.Resecting the posterior portion 102e and / or the tibial portion 104a during a TKA can compromise, damage, or even destroy these soft tissues, which may decrease at least the safety, accuracy and / or efficiency of the procedure for any cut(s) that remain(s) to be performed as part of the TKA after resecting the posterior portion 102e and / or the tibial portion 104a. Therefore, it may be desired to perform these resections of the posterior portion 102e and / or the tibial portion 104 as late in the process as possible (e.g., after any other cut(s)).Atty. Docket No. : 5247.033 A WO

[0063] Specifically, there are forces applied to the knee joint, including vibrations from the cutting tool as well as other forces applied to the cutting tool to push the cutting tool further into the bone(s) of the knee joint (e.g., the femur 102, tibia 104 and / or patella 106) which may compromise or otherwise threaten the stability of the knee joint as resections are made. Another major compromising factor is that as bone is removed from the knee joint (e.g., following resection(s)), soft tissue(s) (e.g., ligaments) the knee experience a progressive reduction in their capacity to maintain the stability of the knee. In an aspect of the method, the soft tissues that naturally tension the femur 102 and / or the tibia 104 relative to each other may advantageously be maintained for as long as possible during the TKA (e.g. until after other cuts of the TKA have been performed) such that these soft tissues provide at least some degree of resistance to the various forces which are applied to the knee joint during the procedure. It may therefore be advantageous to plan a resection profile in which the posterior portion 102e and / or the tibial portion 104a are resected later, or in some embodiments, preferably, after all of the other TKA cuts described herein are performed in order to maintain the natural anatomic tensioning between the femur 102 and the tibia 104 that is provided by the various soft tissues located in the space 108 therebetween. In embodiments, performing 1240 the posterior femoral cut 116 and performing 1130 the tibial cut(s) 120 may occur in either order relative to each other.

[0064] In some embodiments, performing 1240 the posterior femoral cut 116 may generate bone chips as the posterior portion 102e is resected. In such embodiments, where the posterior femoral cut 116 is performed before the tibial cut 120, it may be desirable as an additional means of maintaining the stability of the knee joint to optionally remove or otherwise clean out the bone chips only after performing 1130 the tibial cut(s) 120. Waiting before cleaning out the bone chips may prevent destabilizing disturbances to the tibia 104 and / or the soft tissue(s) in proximity thereof, which could compromise the safety, efficiency and / or accuracy of the TKA.

[0065] In embodiments, performing the tibial cut 120 may thus be achieved following performing the femoral cut(s), as shown in FIGS. 7-8. In such embodiments, the posterior femoral cut 116 may be the last and / or final cut performed during performance of the femoral cut(s). By performing the posterior femoral cutAtty. Docket No. : 5247.033 A WO116 as the final cut of performing the femoral cut(s), and then performing the tibial cut(s), the soft tissues that naturally tension the knee joint are maintained at least throughout performing the femoral cut(s), which may provide a degree of resistance to the various forces applied to the knee during the TKA. The stability provided by soft tissues may contribute to a decreased need to use invasive means to fix the cutting tool relative to the patient’s knee joint. For example, the need to use invasive fixation pins to fix the cutting tool relative to the patient’s knee joint may be reduced, minimized, and / or obviated by the maintenance of natural anatomic tensioning as the femur 102, tibia 104 and / or patella 106 are better able to maintain their position(s) (e.g., relative to each other and / or relative to the cutting tool) throughout the TKA.

[0066] In an aspect, the method may further include performing the patellar cut 122. In embodiments, the patellar cut 122 may be performed at any point between the fixing (e.g. 1110) of the cutting tool relative to the knee joint and the fitting 1140 the knee joint with implant components (described below). In other embodiments, performance of the patellar cut 122 may be optional.

[0067] Continuing with FIG. 11, the process further includes fitting 1140 the femur 102, the tibia 104, and / or the patella 106 with one or more implant component(s). For example, the process may fit the femur 102 with one or more femoral component(s) of the implant components, fit the tibia 104 with one or more tibial component(s) of the implant components, and / or fit the patella 106 with one or more patellar component s) of the implant components. In embodiments, the implant components may include a press-fit and / or non-cemented implant. In other embodiments, the implant components may include cemented implants. In embodiments, fitting the patella 106 with the patellar component may be optional.

[0068] In embodiments, use of a press-fit and / or non-cemented / uncemented implant may be particularly enabled by processes described herein. Specifically, a process may facilitate active, autonomous cutting of the bones (e.g., the femur 102, the tibia 104 and / or the patella 106) of the knee joint by a cutting tool, such as a robotmounted cutting tool. Autonomous systems may be particularly accurate when performing cuts (e.g., performing the femoral cut(s) and / or the tibial cut(s)) asAtty. Docket No. : 5247.033 A WO compared to humans, which may enable precision cuts that are difficult to achieve during manual surgery. Precision cuts facilitated by active robotics may enable the bones (e.g., the femur 102, the tibia 104 and / or the patella 106) of the knee joint to be cut or otherwise shaped into a shape and / or geometry which is within a threshold degree of a corresponding geometry of one or more component(s) of a press-fit and / or non-cemented implant with which the bone(s) will engage (e.g., via press-fitting). In an example, the threshold is 3 millimeters (mm) of error and / or three degrees of error, though this is just one example; the threshold could be any desired threshold. Alternatively, the method may facilitate the use of cemented implants in the knee joint.

[0069] In embodiments, after performing the femoral cut(s) on the femur and performing the tibial cut(s) on the tibia, it may be desirable to further shape the femur 102, the tibia 104 and / or the patella 106 to accommodate the respective implant component(s). For example, further shaping may be desirable where a surgeon decides intraoperatively that the knee joint should be shaped to better facilitate implant fit and / or accommodate implant components of a different size than the surgeon originally anticipated. As a further example, further shaping may be desirable where a press-fit, uncemented implant is only slightly too small to be accommodated by the relevant bone of the knee joint, requiring slight modifications. This shaping is considered to be part of the fitting 1140 the knee joint with the implant component(s).

[0070] Aspects described herein can be helpful for surgical navigation technology and / or systems, navigated surgical procedures, and other applications. Aspects could be integrated into robotic (autonomous and / or semi-autonomous) surgical systems, for example. In some embodiments, aspects are provided as software that can be integrated into target systems, and / or which may direct a robot to perform aspects of the method disclosed herein.

[0071] One or more embodiments described herein may be incorporated in, performed by, and / or used by one or more computer systems, such as one or more systems that are, or are in communication with, a camera system, tracking system, and / or surgical robot, as examples. Processes described herein may be performedAtty. Docket No. : 5247.033 A WO singly or collectively by one or more computer systems. A computer system may also be referred to herein as a data processing device / system, computing device / system / node, or simply a computer. The computer system may be based on one or more of various system architectures and / or instruction set architectures.

[0072] FIG. 13 depicts an example computer system to incorporate, use, and / or facilitate aspects described herein. Computer system 1300 may be provided as part of a surgical navigation technology / system, for example. Computer system 1300 may be in communication with one or more external device(s) 1312 (such as one or multiple robot(s), tracking camera(s), rigid robot tracking array(s), foot pedal(s), monitor(s), Deadman switch(es), etc.). Computer system 1300 includes one or more processor(s) 1302, for instance central processing unit(s) (CPUs). A processor can include functional components used in the execution of instructions, such as functional components to fetch program instructions from locations such as cache or main memory, decode and execute program instructions, access memory for instruction execution, and write results of the executed instructions. A processor of processor(s) 1302 can also include register(s) to be used by one or more of the functional components. Computer system 1300 also includes memory 1304, input / output (I / O) devices 1308, and I / O interfaces 1310, which may be coupled to the processor(s) 902 and each other via one or more buses and / or other connections. Bus connections represent one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any variety of bus architectures. By way of example, and not limitation, such architectures include the Industry Standard Architecture (ISA), the Micro Channel Architecture (MCA), the Enhances ISA (EISA), the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI).

[0073] Memory 1304 can be or include main or system memory (e.g., Random Access Memory) used in the execution of program instructions, storage device(s) such as hard drive(s), flash media, or optical media as examples, and / or cache memory, as examples. Memory 1304 can include, for instance, a cache, such as a shared cache, which may be coupled to local caches (examples include LI cache, L2 cache, etc.) ofAtty. Docket No. : 5247.033 A WO processor(s) 1302. Additionally, memory 1304 may be or include at least one computer program product having a set (e.g., at least one) of program modules, instructions, code or the like that is / are configured to carry out functions of embodiments described herein when executed by one or more processors.

[0074] Memory 1304 can store an operating system 1305 and other computer programs 1306, such as one or more computer programs / applications that execute to perform aspects described herein. Specifically, programs / applications can include computer readable program instructions that may be configured to carry out functions of embodiments of aspects described herein.

[0075] Examples of VO devices 1308 include but are not limited to microphones, speakers, Global Positioning System (GPS) devices, RGB, IR, and / or spectral cameras, lights, accelerometers, gyroscopes, magnetometers, sensor devices configured to sense light, proximity, heart rate, body and / or ambient temperature, blood pressure, and / or skin resistance, registration probes and activity monitors. An VO device may be regarded as an external device (1312) coupled to the computer system through one or more VO interfaces 1310.

[0076] Computer system 1300 may communicate with one or more external devices 1312 via one or more VO interfaces 1310. Example external devices include a keyboard, a pointing device, a display, and / or any other devices that enable a user to interact with computer system 1300. Other examples of external devices include any device that enables computer system 1300 to communicate with one or more other computing systems or peripheral devices such as a printer. A network interface / adapter is an example VO interface that enables computer system 1300 to communicate with one or more networks, such as a local area network (LAN), a general wide area network (WAN), and / or a public network (e.g., the Internet), providing communication with other computing devices or systems, storage devices, or the like. Ethernet-based (such as Wi-Fi) interfaces and Bluetooth® adapters are just examples of the currently available types of network adapters used in computer systems (BLUETOOTH is a registered trademark of Bluetooth SIG, Inc., Kirkland, Washington, U.S.A.).Atty. Docket No. : 5247.033 A WO

[0077] The communication between I / O interfaces 1310 and external devices 1312 can occur across wired and / or wireless communications link(s) 1311, such as Ethernet-based wired or wireless connections. Example wireless connections include cellular, Wi-Fi, Bluetooth®, proximity-based, near-field, or other types of wireless connections. More generally, communications link(s) 1311 may be any appropriate wireless and / or wired communication link(s) for communicating data.

[0078] Particular external device(s) 1312 may include one or more data storage devices, which may store one or more programs, one or more computer readable program instructions, and / or data, etc. Computer system 1300 may include and / or be coupled to and in communication with (e.g., as an external device of the computer system) removable / non-removable, volatile / non-volatile computer system storage media. For example, it may include and / or be coupled to a non-removable, nonvolatile magnetic media (typically called a “hard drive”), a magnetic disk drive for reading from and writing to a removable, non-volatile magnetic disk (e.g., a “floppy disk”), and / or an optical disk drive for reading from or writing to a removable, nonvolatile optical disk, such as a CD-ROM, DVD-ROM, or other optical media.

[0079] Aspects of the present disclosure may be a system, a method, and / or a computer program product, any of which may be configured to perform or facilitate aspects described herein. Computer system(s) configured to perform these and other methods, and computer program products that include a computer readable storage medium storing instructions for execution to perform these and other methods are also provided.

[0080] Computer system 1300 may be operational with numerous other general purpose or special purpose computing system environments and / or configurations. Computer system 1300 may take any of various forms, well-known examples of which include, but are not limited to, personal computer (PC) system(s), server computer system(s), such as messaging server(s), thin client(s), thick client(s), workstation(s), laptop(s), handheld device(s), mobile device(s) / computer(s) such as smartphone(s), tablet(s), and wearable device(s), multiprocessor system(s), multiprocessor-based system(s), telephony device(s), network appliance(s) (such asAtty. Docket No. : 5247.033 A WO edge appliance(s)), virtualization device(s), storage controller(s), set top box(es), programmable consumer electronic(s), network PC(s), minicomputer system(s), mainframe computer system(s), and distributed cloud computing environment(s) that include any of the above systems or devices, and the like.

[0081] In some embodiments, aspects of the present disclosure may take the form of a computer program product, which may be embodied as computer readable medium(s). A computer readable medium may be a tangible storage device / medium having computer readable program code / instructions stored thereon. Example computer readable medium(s) include, but are not limited to, electronic, magnetic, optical or semiconductor storage device or systems, or any combination of the foregoing. Example embodiments of a computer readable medium include a hard drive or other mass-storage device, an electrical connection having wires, random access memory (RAM), read-only memory (ROM), erasable-programmable read-only memory such as EPROM or flash memory, an optical fiber, a portable computer disk / diskette, such as a compact disc read-only memory (CD-ROM) or Digital Versatile Disc (DVD), an optical storage device, a magnetic storage device, or any combination of the foregoing. The computer readable medium may be readable by a processor, processing unit, or the like, to obtain data (e.g., instructions) from the medium for execution. In a particular example, a computer program product is or includes one or more computer readable media that includes / stores computer readable program code to provide and facilitate one or more aspects described herein.

[0082] As noted, program instruction contained or stored in / on a computer readable medium can be obtained and executed by any of various suitable components such as a processor of a computer system to cause the computer system to behave and function in a particular manner. Such program instructions for carrying out operations to perform, achieve, or facilitate aspects described herein may be written in, or compiled from code written in, any desired programming language. In some embodiments, such programming language includes object-oriented and / or procedural programming languages such as C, C++, C#, Java, etc.Atty. Docket No. : 5247.033 A WO

[0083] Program code can include one or more program instructions obtained for execution by one or more processors. Computer program instructions may be provided to one or more processors of, e.g., one or more computer systems, to produce a machine, such that the program instructions, when executed by the one or more processors, perform, achieve, or facilitate aspects of the present disclosure, such as actions or functions described in flowcharts and / or block diagrams described herein. Thus, each block, or combination of blocks, of the flowchart illustrations and / or block diagrams depicted herein can be implemented, in some embodiments, by computer program instructions.

[0084] While several aspects of the present disclosure have been described and depicted herein, alternative aspects may be effected by those skilled in the art to accomplish the same objectives. Accordingly, it is intended by the appended claims to cover all such alternative aspects as fall within the true spirit and scope of the disclosure.

[0085] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0086] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below, if any, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of one or more embodiments has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain various aspects and the practicalAtty. Docket No. : 5247.033 A WO application, and to enable others of ordinary skill in the art to understand various embodiments with various modifications are suited to the particular use contemplated.

Claims

Atty. Docket No. : 5247.033 A WOCLAIMSWhat is claimed is:

1. A method to facilitate a robotic total knee arthroplasty, the method including: performing a plurality of femoral cuts on a femur, the performing the plurality of femoral cuts including; performing a distal femoral cut of the plurality of femoral cuts; performing an anterior femoral cut of the plurality of femoral cuts; performing an anterior chamfer cut of the plurality of femoral cuts after the performing the distal femoral cut and the performing the anterior femoral cut; and performing a posterior femoral cut of the plurality of femoral cuts after performing all other femoral cuts of the plurality of femoral cuts; and performing at least one tibial cut on a tibia after the performing the plurality of femoral cuts on the femur.

2. The method of claim 1, wherein the performing the plurality of femoral cuts on the femur further includes performing the distal femoral cut before performing the anterior femoral cut.

3. The method of claim 1, wherein the performing the plurality of femoral cuts on the femur further includes performing the anterior femoral cut before performing the distal femoral cut.

4. The method of claim 1, wherein the performing the distal femoral cut and the performing the anterior femoral cut further include reducing an amount of bone in a plane of a cut path of the anterior chamfer cut.

5. The method of claim 1, wherein the performing the distal femoral cut further includes removing femoral material from a distal portion of the femur such that aAtty. Docket No. : 5247.033 A WO substantially planar bone surface is formed on a distal portion of the femur to facilitate penetration of an anterior chamfer portion of the femur by a cutting tool when performing the anterior chamfer cut.

6. The method of claim 5, wherein the performing the anterior chamfer cut further includes cutting the anterior chamfer portion of the femur with the cutting tool, the cutting tool commencing cutting along a cut path of the anterior chamfer cut through the substantially planar bone surface.

7. The method of claim 1, wherein the performing the anterior femoral cut further includes removing femoral material from an anterior portion of the femur such that a substantially planar bone surface is formed on an anterior portion of the femur to facilitate penetration of an anterior chamfer portion of the femur by a cutting tool when performing the anterior femoral cut.

8. The method of claim 7, wherein the performing the anterior chamfer cut further includes cutting the anterior chamfer portion of the femur with the cutting tool, the cutting tool commencing cutting along a cut path of the anterior chamfer cut through the substantially planar bone surface.

9. The method of claim 1, further including fixing a robotic cutting tool relative to the femur and / or tibia without use of external fixation pins, the robotic cutting tool to be used in performing at least one femoral cut of the plurality of femoral cuts and / or in performing the at least one tibial cut.

10. The method of claim 1, further including maintaining a natural anatomic tensioning between the femur and the tibia at least until the performing the posterior femoral cut.

11. The method of claim 1, further including press-fitting an uncemented, press-fit implant to the femur.

12. The method of claim 1, wherein the performing the plurality of femoral cuts further includes performing a posterior chamfer cut of the plurality of femoral cuts,Atty. Docket No. : 5247.033 A WO and wherein the posterior femoral cut is a last femoral cut performed as part of the robotic total knee arthroplasty.

13. A method to facilitate a robotic total knee arthroplasty, the method including: performing a plurality of femoral cuts on a femur, the performing the plurality of femoral cuts including: performing a distal femoral cut of the plurality of femoral cuts; performing an anterior femoral cut of the plurality of femoral cuts; and performing an anterior chamfer cut of the plurality of femoral cuts after the performing the distal femoral cut and the performing the anterior femoral cut.

14. A method to facilitate a robotic total knee arthroplasty, the method including: performing a plurality of femoral cuts, the performing the plurality of femoral cuts including performing a posterior femoral cut of the plurality of femoral cuts after performing all other cuts of the plurality of femoral cuts; and performing a tibial cut on a tibia after the performing the plurality of femoral cuts.

15. A computer system including: a memory; and a processing circuit in communication with the memory, wherein the computer system is configured to perform a method of any of claims 1-14.

16. A computer program product including: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method of any of claims 1-14.

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