Systems and methods for tibial osteotomy based on knee kinematic alignment

Abstract

A tibial osteotomy system includes a trial member configured to be installed as a substitute for an implant on a distal portion of a femur; and a cutting guide detachably attachable to the trial member, wherein the cutting guide is provided with a guide portion that guides a tibial cutting tool relative to the trial member.

Description

Atty. Docket No. 315172000140SYSTEMS AND METHODS FOR TIBIAL OSTEOTOMY BASED ON KNEE KINEMATIC ALIGNMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Application No. 63 / 679,147 filed August 4, 2024, the contents of which is incorporated by reference in its entirety.FIELD

[0002] The present disclosure relates to an osteotomy system.BACKGROUND

[0003] Total knee arthroplasty (TKA) is known as an effective surgical intervention for patients with end-stage osteoarthritis (OA) of the knee. In the United States, more than 700,000 TKA procedures are performed annually. However, despite the high success rate, approximately 20% of patients report dissatisfaction due to persistent postoperative pain, functional limitations, and a sense of instability. Many of these problems stem from the limitations of the conventional mechanical alignment (MA) approach used in TKA. Mechanical alignment aims to position the knee components perpendicular to the mechanical axis of the leg in order to produce a straight limb postoperatively. In particular, conventional tibial osteotomy has been performed based on measurements taken from the ankle, while conventional femoral osteotomy has been conducted separately with consideration of the functional axis — each step being done independently. However, this method does not take into account the natural kinematics of the knee and can result in altered gait patterns, increased ligament strain, and improper load distribution across the joint. Studies have shown that mechanical alignment can cause patellofemoral complications, such as poor tracking and increased wear, which contribute to anterior knee pain and reduced patient satisfaction.Kinematic alignment approaches to TKA, by contrast, include determining tibial resection volume, rotational angle, and varus / valgus angle based on the distal-most point of the femur in full extension, while also considering the tension and elasticity of the surrounding ligaments. However, these determinations are typically made independently and not in an integrated manner, which can lead to inaccuracies and poor outcomes.1MOFO-358353868Atty. Docket No. 315172000140

[0004] To overcome these challenges, accurate bone cutting at the correct position is important to achieving proper alignment.SUMMARY

[0005] According to various aspects of the present disclosure, system and methods guide tibial cutting such that a tibial cut is orientation according to a kinematic alignment of the knee. An osteotomy system includes a trial member configured to be mounted to the distal femur as a substitute for an implant, and a cutting guide that is attachable to the trial member such that a guide portion of the cutting guide configured to guide a tibial cutting instrument is positioned at a predetermined orientation with respect to the trial member. Optionally, the guide portion is configured to direct the tibial cutting instrument based on the state in which the tension of the medial and lateral collateral ligaments is reproduced, and the guide portion is configured to be positioned in a predetermined direction relative to the trial component.This configuration provides a tibial osteotomy that respects the natural kinematics of the knee during TKA, thereby improving patient satisfaction and ensuring long-term implant stability.

[0006] According to an aspect, an osteotomy system includes: a trial member configured to be installed as a substitute for an implant on a distal portion of a femur; and a cutting guide detachably attachable to the trial member, wherein the cutting guide is provided with a guide portion that guides a tibial cutting tool relative to the trial member.

[0007] The cutting guide may include a blade that is aligned with the guide portion in a coronal view, and the trial member may include a mounting portion configured such that, when the trial member is installed on the femur, the blade can be attached to the trial member in parallel with a distal femoral osteotomy surface.

[0008] The cutting guide may include a junction body configured to be attachable and detachable with respect to both the guide portion and the blade; and a cutting block comprising the guide portion and configured to be attachable and detachable with respect to the junction body.

[0009] The junction body may include a mounting portion that is attachable and detachable with respect to the guide portion, and the junction body may be configured such that, when the blade is mounted to the junction body, the blade is positioned with respect to the guide2MOFO-358353868Atty. Docket No. 315172000140 portion at a predetermined angle in a plane that is parallel to a coronal plane. The junction body may include: a first mounting portion that is attachable and detachable with respect to the guide portion; and a second mounting portion for attaching the blade at an angle relative to the mounting portion. The osteotomy system may include a plurality of junction bodies having a plurality of different angles. The cutting block may include a slot extending along the guide portion and configured to receive an attachment component for attaching the cutting block to a tibia.

[0010] The osteotomy system may include a measurement instrument detachably mountable to the cutting guide, the measurement instrument being configured to measure an inclination of the guide portion with respect to a transverse plane of a tibia. The measurement instrument may include: a scale portion detachably connected to the cutting guide; and a swingable member connected to the scale portion, wherein the scale portion is provided with markings indicating an angle of the swingable member relative to the scale portion.

[0011] The guide portion may be a slot configured to allow insertion of a cutting tool in an insertion direction. The system may include a filler configured to be positioned between the trial member and the tibia to control a position of a tibia relative to the trial member.

[0012] According to an aspect, a trial member is configured to be installed as a substitute for an implant on a distal portion of a femur, the trial member include a mounting portion to which a cutting guide, configured to guide a tibial cutting tool, is detachably attachable.

[0013] According to an aspect, a cutting guide is configured to be detachably attachable to the above trial member. The cutting guide is configured to guide a tibial cutting tool at a predetermined position relative to the trial member.

[0014] According to an aspect, a tibial osteotomy system includes a trial member configured to be attached to a distal femoral osteotomy surface as a temporary substitute for an implant; and a cutting guide configured to mount to the trial member and guide a tibial cutting tool relative to the trial member.

[0015] The cutting guide may include a guide portion for receiving and guiding the tibial cutting tool, the guide portion being oriented at a predetermined angle relative to the trial member when the cutting guide is mounted to the trial member. The predetermined angle may be a zero-degree angle in a plane parallel to a coronal plane. The cutting guide may3MOFO-358353868Atty. Docket No. 315172000140 include a cutting block that comprises the guide portion, wherein the cutting block is configured for attaching to a tibia. The guide portion may be a slot, and the trial member may include a slot for receiving a portion of the cutting guide for mounting the cutting guide to the trial member, wherein the slot of the cutting guide has a predetermined orientation with respect to the slot of the trial member when the cutting guide is mounted to the trial member. The cutting guide may include a bracket system configured to attach to the cutting block and the trial member. The guide portion may be a slot of the cutting block, and a portion of the bracket system may be received in the slot to attach the cutting block to the bracket system. The bracket system may be configured to define a posterior slope of the tibial osteotomy.

[0016] The system may include at least one cutting angle adjustment block that comprises a guide portion configured to guide the tibial cutting tool at a different orientation than the guide portion of the cutting block. The different orientation may include at least one of a different posterior slope angle or a different varus / valgus angle. The system may include a filler configured to be positioned between the trial member and the tibia to control a position of a tibia relative to the trial member.

[0017] According to an aspect, a kit may include any of the tibial osteotomy systems described above. At least one component of the cutting guide may be provided in a plurality of different configurations. The plurality of different configurations may be configured to provide a plurality of different orientations of a cutting tool guide portion of the cutting guide relative to the trial member. The plurality of different orientations may include a plurality of different posterior slope angles. The kit may include at least one cutting angle adjustment block configured to provide different cutting angles in a plane parallel to a coronal plane. The kit may include an instrument for determining the cutting angle in the plane parallel to the coronal plane. The kit may include a filler configured to be positioned between the trial member and a tibia to control a position of a tibia relative to the trial member.

[0018] According to an aspect, a method for tibial osteotomy includes attaching a trial member to a distal femoral osteotomy surface of a femur as a temporary substitute for an implant; mounting a cutting guide to the trial member to position the cutting guide relative to the trial member; attaching at least a portion of the cutting guide to a tibia; and cutting the tibia based on the position of the cutting guide relative to the trial member.4MOFO-358353868Atty. Docket No. 315172000140

[0019] The cutting guide may include a cutting block, and attaching the cutting guide to the tibia may include attaching the cutting block the tibia. The cutting guide may include a bracket system that attaches to the cutting block and the trial member, and the method may include removing the bracket system from the cutting block prior to cutting the tibia. The method may include, after removing the bracket system from the cutting block and prior to cutting the tibia, further attaching the cutting block to the tibia. The method may include, prior to further attaching the cutting guide to the tibia, adjusting an orientation of the cutting block while the cutting block is attached to the tibia. The cutting block may be attached to the tibia via one or more attachment components, and method comprises removing the cutting block from the tibia and attaching a cutting angle adjustment block to the one or more attachment components. The cutting angle adjustment block may be configured to provide a different orientation of a tibial osteotomy surface than the cutting block. The method may include inserting at least one filler between the trial member and the tibia to control a position of the tibia relative to the trial member and a tension of at least one ligament.

[0020] It will be appreciated that any of the variations, aspects, features, and options described in view of the systems apply equally to the methods and vice versa. It will also be clear that any one or more of the above variations, aspects, features, and options can be combined.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0022] FIG. 1 is a front view of an osteotomy system, according to various embodiments.

[0023] FIG. 2 is a side view of an osteotomy system, according to various embodiments.

[0024] Fig. 3 is a front view of a cutting block according to an embodiment.

[0025] Fig. 4 is a set of views of a junction body and slit blade in combination, including (a) a perspective view, (b) a top view, and (c) a side view according to an embodiment.

[0026] Fig. 5 is a top view (a) and a side view (b) of the junction body according to an embodiment.5MOFO-358353868Atty. Docket No. 315172000140

[0027] Fig. 6 is a top view of the slit blade according to an embodiment.

[0028] Fig. 7 is a set of views of a trial member according to an embodiment, including (a) a side view, (b) an opposite side view, and (c) a bottom view.

[0029] Fig. 8 shows perspective views (a) and (b) of the trial member, junction body, and slit blade in an assembled state, from different viewing angles.

[0030] Fig. 9 includes (a) a side view and (b) a front view of an angle checker according to an embodiment.

[0031] Fig. 10 shows (a) a front view and (b) a side view of the angle checker mounted to the tibia and cutting block.

[0032] FIG. 11 shows an exemplary filler.

[0033] FIGS. 12A and 12B illustrate an exemplary posterior slope cutting angle adjustment block.

[0034] FIG. 13 illustrates an exemplary varus / valgus cutting angle adjustment block.DETAILED DESCRIPTION

[0035] According to various aspects, systems and methods enable tibial osteotomy that respects the natural kinematics of the knee during TKA. A tibial osteotomy system is configured to perform accurate resection of the tibia at an appropriate position, wherein the resection is based on the distal femoral surface (e.g., in full knee extension), and optionally, performed under a condition in which both the medial and lateral collateral ligaments are tensioned (e.g., equally tensioned) and appropriately elongated to replicate their pre-disease state, which can be important for achieving proper alignment. A tibial osteotomy system includes a tibial cutting block configured to be mounted to the tibia such that a guide portion of the cutting block that guides a tibial cutting instrument is positioned at a predetermined orientation associated with kinematic alignment of the knee. The positioning system includes a trial member that is mounted to a distal end of a resected femur. The trial member is configured to match at least a portion of a shape of an implant that is to be implanted into the femur to form the distal end of the femur such that the trial member can serve as a temporary substitute for the implant. A bracket system attaches to the trial member and the cutting6MOFO-358353868Atty. Docket No. 315172000140 block to position the guide portion of the cutting block at a predetermined orientation with respect to the trial member. For example, the osteotomy system may be configured to orient the guide portion of the cutting block at zero degrees to a distal femoral osteotomy surface in the coronal view such that a tibial osteotomy plane is oriented at zero degrees to the distal femoral osteotomy surface in the coronal view when the knee is in an extended position. As such, the osteotomy system guides a tibial osteotomy to provide a predetermined orientation between the tibial osteotomy plane and the trial member with the knee in the extended position. The systems and methods define the tibial resection volume, rotational angle, and varus / valgus angle based on the femur in full extension. In other words, the osteotomy system is configured to register the guide portion of the cutting block to the trial member such that the tibial osteotomy is defined according to the trial member. Orienting the tibial osteotomy plane with respect to the trial member with the knee in the extended position respects the natural kinematics of the knee, which can provide improved TKA outcomes relative to mechanical alignment approaches. Further, the osteotomy system guides accurate cutting of the tibia that avoids human error that could otherwise arise from manual kinematic alignment approaches, which can provide better and more consistent outcomes, particularly for less experienced surgeons.

[0036] Given the substantial matching of the shape of the trial member to the implant, registration of the tibial osteotomy to the trial member, according to the principles described herein, provides registration of the tibial osteotomy to the distal portion of the knee (as it will be after implant placement) and enables a surgeon to visually identify the eventual most distal portion of the femur, which in turn, aids the surgeon in assessing tibial resection volume, posterior slope, gap alignment, ligament tension, varus / valgus angle, and / or soft tissue elasticity, all with the leg in full extension. The osteotomy systems and methods described herein enable a surgeon to make real-time adjustments of the tibial osteotomy plane, such as to achieve a desired posterior slope, desired varus / valgus angle, or desired gap alignment, and / or to account for the ligament tension and soft tissue elasticity. As such, the osteotomy systems and methods described herein provide an integrated approach for defining tibial resection volume, posterior slope, gap alignment, and varus / valgus angle based on the femur in full extension (e.g., the distal-most portion of the femur), while also considering the tension and elasticity of the surrounding ligaments. As such, the systems and methods described herein enable osteotomy to be conducted with consideration for alignment and soft tissue tension.7MOFO-358353868Atty. Docket No. 315172000140

[0037] The cutting block may be available in different configurations that guide different orientations of the tibial osteotomy. For example, different cutting block configurations may provide different posterior slope angles to provide different posterior slopes of the tibial osteotomy plane relative to the trial member. The osteotomy system may include cutting angle adjustment blocks configured to enable a surgeon to cut the tibial osteotomy plane at different orientations than provided by the cutting block. This may enable a surgeon to finetune the tibial osteotomy during the TKA procedure, while still controlling orientation of the tibial osteotomy relative to the trial member.

[0038] In the anatomical structure of the knee joint, the femur serves as the primary element, and the tibia is anatomically subordinate to it. According to various aspects, the systems and methods described herein can enable the tibial resection to be determined with reference to the femur, thereby respecting the natural hierarchical relationship between the two bones. Further, in full knee extension, the medial and lateral collateral ligaments are in their most stable and taut state, the systems and methods described herein can allows tibial resection to be performed in this extended position, using the femur and ligaments as references, which can ensure that the tibial position aligns with its subordinate biomechanical role. Moreover, in a healthy, pre-disease knee, the medial and lateral collateral ligaments are in a state of balanced isometric tension, the systems and methods described herein can reproduce that condition to determine the appropriate tibial resection. In deformed knees, however, the medial tibial plateau is often compromised. To address this, the systems and methods described herein, according to various embodiments, may utilize a filler (e.g., s spoon-shaped compensating tool) to fill the medial joint space in full extension, thereby stretching the loosened medial collateral ligament and restoring its pre-disease length and tension. This enables tibial resection under conditions that replicate the native knee, allowing for kinematic alignment to be properly restored.

[0039] In the following description of the disclosure and embodiments, reference is made to the accompanying drawings in which are shown, by way of illustration, specific embodiments that can be practiced. It is to be understood that other embodiments and examples can be practiced, and changes can be made without departing from the scope of the disclosure.

[0040] In addition, it is also to be understood that the singular forms “a,” “an,” and “the” used in the following description are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is also to be understood that the term “and / or” as used8MOFO-358353868Atty. Docket No. 315172000140 herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It is further to be understood that the terms “includes, “including,” “comprises,” and / or “comprising,” when used herein, specify the presence of stated features, integers, steps, operations, elements, components, and / or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and / or groups thereof.

[0041] FIG. 1 illustrates an exemplary osteotomy system 1. The osteotomy system 1 includes multiple components positioned relative to the tibia A and femur (not shown) to guide cutting of the upper portion of the tibia A to provide a mounting location for a tibial implant.

[0042] In the following description, the orientation of the osteotomy system 1 will be defined with reference to the anatomical directions of the human body in the extended knee position, as shown in FIGS. 1 to 10. The transverse, coronal, and sagittal planes are also defined accordingly for explanation purposes. Although the embodiment is primarily described for use on the left leg, the osteotomy system 1 can also be used on the right leg. Any of the components of an osteotomy system according to the principles described herein may be configured for use on either the left leg or the right leg. Any of the components of an osteotomy according to the principles described herein may have different configurations for use on either the left leg or the right leg (e.g., two different variations that are mirror images of one another).

[0043] As shown in FIGS. 1 and 2, the osteotomy system 1 includes a trial member 3 and a cutting guide 2. The trial member 3 is configured to be mounted to a resected distal surface of a femur as a temporary substitute for the implant. As a temporary substitute for the implant, at least a portion of the shape of the trial member 3 is substantially identical to the implant intended to be permanently mounted to the resected distal surface of the femur, and as such, is configured according to the patient's body shape, particularly the femoral geometry (e.g., based on pre-operative imaging).

[0044] The cutting guide 2 includes a cutting block 21 that is configured to attach to the tibia A for guiding cutting of the tibia A. The cutting block 21 includes a rear portion 212 configured to be positioned against the tibia A and a front portion 211 located opposite the rear portion 212. The illustrated example is a cutting block 21 for the left leg; for the right9MOFO-358353868Atty. Docket No. 315172000140 leg, a mirror-symmetric version can be used. The cutting block 21 may be made of any suitable material, such as metal (e.g., stainless steel) or rigid plastic.

[0045] The cutting block 21 further includes a plurality of holes configured for receiving attachment components, such as pins or screws. The illustrated example includes a plurality of attachment pin holes 21 A, which may be circular through-holes configured to receive attachment pins (not shown). The cutting block 21 may include at least one rotational adjustment pin hole 21B, which may be configured as a through-hole that has an elliptical shape when viewed from the front and allows insertion of an attachment pin while also enabling rotational adjustment of the cutting block 21 with the pin inserted. The cutting block 21 may include one or more mounting holes 21D, which may be through holes configured to allow attachment and support of an angle checker, as discussed further below.

[0046] The cutting block 21 includes a guide portion in the form of a slot 21C that is configured to guide a cutting instrument to cut the tibia. The slot 21C is an elongated opening formed in the upper part of the cutting block 21 that extends in the left-right direction. The slot 21C allows insertion of a cutting tool in the anteroposterior direction (the insertion direction shown in Fig. 1) and functions to guide the cutting tool along the shape of the slot 21C for cutting the tibia A.

[0047] The cutting guide 2 includes a bracket system 10 that is configured to position the cutting block 21 at a predetermined position relative to the trial member 3. The bracket system 10 may include a junction body 22 and a slit blade 23.

[0048] The junction body 22 includes a mounting portion 221 for mounting the junction body 22 and the slit blade 23 together, a fastener 223 for fastening the junction body 22 to the slit blade 23, and a plate portion 222 for mounting the junction body 22 and the cutting guide 2 together. The junction body 22 may have a V-shape or U-shape when viewed in the left-right direction (sagittal view during installation).

[0049] The mounting portion 221 is provided at the upper part of the junction body 22 and may have a flat upper surface. An internal thread (not shown) may be formed in the mounting portion 221 for receiving the fastener 223. The internal thread may be formed either by via a nut or by threading directly into the mounting portion 221.10MOFO-358353868Atty. Docket No. 315172000140

[0050] The plate portion 222 is a flat plate- shaped component provided at the lower part of the junction body 22 and extends in both the anteroposterior and left-right directions.

[0051] The fastener 223 may be a bolt threaded into the threaded hole of the mounting portion 221. By loosening or tightening the fastener 223, the operator can attach or detach the slit blade 23 from the mounting portion 221. In some embodiments, alternative fastening mechanisms may be used instead of a bolt to secure the slit blade to the mounting portion. For example, a quick-release pin, a spring-loaded latch mechanism, or a magnetic coupling system may be employed. In other embodiments, a cam-lock fastener or a twist-lock mechanism may provide quick engagement and disengagement. Furthermore, a threaded knob or a lever-operated clamp may offer convenient adjustment without the need for additional tools. These alternative fastening methods may provide various advantages, such as faster assembly, tool-free operation, and / or enhanced stability, depending on the specific requirements of the osteotomy system.

[0052] As shown in Fig. 4(c), the upper surface of the mounting portion 221 and the plate portion 222 are configured to form an angle C in the left-right (lateral) view that controls a posterior slope of the tibial osteotomy. The illustrated example has an angle C having a value of zero. However, this is merely exemplary as angle C may have a non-zero value, such as a value greater than zero or a value less than zero. In the anteroposterior (also referred to as the coronal view), the upper surface of the mounting portion 221 and the plate portion 222 are parallel in the coronal view, meaning that a line formed by the intersection of the upper surface of mounting portion 221 with a plane parallel to a coronal plane is parallel to a line formed by the intersection of the upper surface of the plate portion 222 with the coronal plane (as used herein, “parallel in the anteroposterior view or coronal view” means that intersections of components with a plane parallel to a coronal plane are parallel). The junction body 22 may be available in multiple variants with different values of angle C (e.g., in a kit that comprises the trial member and the cutting guide 2) to provide a surgeon with choices for the posterior slope of the tibial osteotomy. Alternatively, a junction body may be configured such that angle C is adjustable. For example, a junction body may include an adjustment mechanism that enables a surgeon to adjust the angle C (and / or a spacing between the portion that attaches to the trial member and the portion that attaches to the cutting block). The adjustment mechanism may include a ratcheting mechanism, such as a spring-loaded ratcheting mechanism, or may include a motorized system. The adjustment mechanism may11MOFO-358353868Atty. Docket No. 315172000140 be configured to provide predetermined settings for angle C. In some examples, the angle C may be adjusted by a surgeon by bending at least one of the mounting portion 221 and plate portion 222. In some variations, the upper surface of the mounting portion 221 and the plate portion 222 are non-parallel in the coronal view, such as for providing a non-zero varus / valgus angle for the tibial osteotomy. Other aspects of junction body 22 may be different in different variations, such as the spacing between the upper surface of the mounting portion 221 and the plate portion 222 (which defines the spacing between the trial member and the tibial osteotomy plane). The presence of the trial member 3 enables a surgeon to visually identify the eventual distal most surface of the femur (resulting from implant placement), which may aid a surgeon in selecting the appropriate variation of junction body 22 (in examples in which multiple different variations are available).

[0053] The slit blade 23 is configured to engage the junction body 22 and the trial member 3. The slit blade 23 may be configured as a flat plate- shaped component and includes a front extending fixing portion 231 for engaging the junction body 22 and a rear extending rear end portion 232 for engaging the trial member 3. As shown in Fig. 6, the fixing portion 231 includes a junction body engagement portion, which in the illustrated example is in the form of a slit 231 A that extends in the anteroposterior direction and through which the fastener 223 can pass. The fastener 223 is tightened to the mounting portion 221 at an appropriate position along slit 231 A, thereby clamping and fixing the fixing portion 231 between the mounting portion 221 and the fastener 223.

[0054] When the fixing portion 231 is secured to the mounting portion 221, the slit blade 23 extends along the upper surface of the mounting portion 221. Accordingly, when mounted, the slit blade 23 forms the angle C relative to the plate portion 222 in the left-right view (see Fig. 4(c)). As such, the slit blade 23 is arranged parallel to the plate portion 222 in the anteroposterior or coronal view (see Fig. 1).

[0055] The rear end portion 232 of the slit blade 23 may be fork- shaped, formed by two elongated and parallel members. The rear end portion 232 is configured to be inserted into the trial member 3, specifically into slot(s) 3A (see FIG. 7A). The prongs may friction-fit into slot(s) 3 A such that the slit blade 23 is fixed in position relative to the trial member 3.

[0056] As shown in Figs. 7(a) to 7(c), the trial member 3 is generally arcuate in the mediolateral direction and includes support portions 31A and 3 IB, which are shaped to cover12MOFO-358353868Atty. Docket No. 315172000140 the lateral and medial femoral condyles, respectively. The upper surfaces of the support portions 31A and 3 IB may be formed with a combination of multiple planar facets, designed to conform to the osteotomized surface of the distal femur. The central planar regions 33A and 33B are formed to extend mediolaterally and anteroposteriorly so as to conform to the osteotomized surfaces of the femoral condyles. Furthermore, the trial member 3 may include one or more protrusions 32 extending from the planar regions 33A and 33B and configured to be inserted into a preformed hole in the femoral condyle, thereby securing the trial member 3 to the osteotomized femur.

[0057] A groove 3 A is formed on the underside of the trial member 3, spanning the support portions 31A and 3 IB. The groove 3A may extend parallel to the planar regions 33A and 33B — that is, in both the mediolateral and anteroposterior directions — and is configured to allow insertion of the rear end portion 232 of the slit blade 23. In some examples, the groove 3 A is non-parallel with the planar regions 33 A and 33B. The trial member 3 is capable of supporting the rear end portion 232 when it is inserted into the groove 3A. In examples in which the groove 3A is formed parallel to the planar regions 33A and 33B, the groove 3A allows the slit blade 23 to be positioned parallel to the distal femoral osteotomy surface.

[0058] In some embodiments, the trial member 3 includes at least one load sensor configured to measure contact forces generated between the trial member and the femoral condyles. The load sensor(s) may be communicatively connected to a computing system, which may be configured to display load data based on sensor signals, enabling the surgeon to evaluate soft tissue balance and make informed decisions regarding implant size and positioning. This feature may optimize knee kinematics and improve postoperative outcomes.

[0059] As shown in Figs. 9(a) to 10(b), the osteotomy system may include an angle checker 4 configured to enable a surgeon to check an angle at which the cutting block will guide the tibial osteotomy. The angle checker 4 may include a rod 42 for aligning with the tibia. The rod 42 may be pivotably mounted to a scale portion 41 that includes a scale 41A (e.g., markings) for showing an angle of the rod 42 (and, thereby, the tibia) relative to the cutting block 21.

[0060] The scale portion 41 may be a plate- shaped member extending vertically and horizontally and including a radial scale 41A formed on its front surface. The scale 41A indicates the inclination angle of the slot 21C about the screw 44 and allows the swing angle13MOFO-358353868Atty. Docket No. 315172000140 formed by the rod 42 relative to the scale portion 41 to be read. The rod 42 is a bar-shaped component pivotally supported at its upper end by the screw 44. An indicator 42A is formed to protrude upward from the top of the rod 42. By viewing the scale portion 41 from the front, the surgeon can read the scale 41 A indicated by the indicator 42A and thereby recognize the swing angle of the rod 42 relative to the scale portion 41, which corresponds to the inclination of the slot 21C.

[0061] In other embodiments, the angle checker 4 may be an electronic component or include electronic components. For example, the angle checker 4 may include an angle sensor that may provide angle data to a computing system (e.g.., via a wired or wireless connection).The computing system may be integrated into the angle checker 4 or may be communicatively connected to the angle checker 4 (e.g., the same computing system may receive load sensor data as discussed above and angle data). The computing system may include, or be communicatively connected to, a display and configured to display angle data (e.g., in real time). This reduces reliance on visually reading mechanical scales and improves measurement accuracy. The angle checker 4 may support wireless connectivity, allowing data transmission to a surgical navigation system or recording of measurements for later analysis.

[0062] The angle checker 4 may include at least one protrusion 43 that extends rearward from the scale portion 41. The at least one protrusion 43 may be configured to be received in one or more of the mounting holes 21D of the cutting block 21. By inserting the protrusion 43 into the mounting hole 21D, the angle checker 4 can be removably attached to the cutting block 21. Other removable attachment approaches may be used, including magnetic attachment of the angle checker 4 to the cutting block 21. Additional examples of fixation include inserting a plate- shaped member into the slot 21C, using the pin holes 21 A or any other attachment holes, and using a clip-like mechanism to attach to the cutting block 21.

[0063] The angle checker 4 may include a screw 44 that penetrates the upper end of the rod 42 and supports it in a pivotable manner. The screw 44 is threaded into a female thread (not shown) provided in the scale portion 41, thereby fixing it to the scale portion. Furthermore, by tightening the screw 44, the rod 42 can be fixed to the scale portion 41, thereby preventing its swinging motion and ensuring accurate reading of the scale 41A.14MOFO-358353868Atty. Docket No. 315172000140

[0064] Angle checker 4 is merely one example of a device for checking the angle at which the cutting block will guide the tibial osteotomy. Any suitable angle determining device may be used. For example, the position of the tibia relative to the portion of the angle determining device mounted to the tibia in association with the cutting block may be assessed based on an anatomical landmark, data from one or more sensors, and / or data from a visual guidance system.

[0065] The osteotomy system may include at least one filler configured to adjust a spacing between the femur and the tibia A. An exemplary filler 5 is shown in Fig. 11. The illustrated filler 5 includes a shaft portion 51, which is a rod-shaped member, and filler portions 52 provided at both ends of the shaft portion 51. The filler portion 52 may be a plate-like component with a curved surface resembling that of an ellipsoid and has a spoon-like shape configured to at least partially correspond to a convex curvature of the surface of the trial member 3. It is inserted between the trial member 3 and the tibia A and is used to adjust the spacing between them and / or to restore the appropriate length and tension of a loosened collateral ligament by compensating for the bone defect. The spoon-shaped surface is sized and spaced according to the patient's anatomical shape.

[0066] As an alternative to tibial traction as described within, inserting the filler can reproduce an equivalent effect. The filler 5 may be available in multiple variations differing in the shape, size, and thickness of the filler portion 52, allowing the surgeon to select the most appropriate one according to the patient’s anatomy during surgery. Additionally, or alternatively, the filler 5 may be customized for the individual patient (e.g., based on preoperative imaging of the patient). For example, it may be manufactured by adding to or subtracting from the material so as to optimize the spacing between the femur and the tibia A. The filler 5 may be fabricated either during or prior to the surgery. By reproducing the appropriate tension of the medial and lateral collateral ligaments, the original joint line can be accurately restored.

[0067] The filler 5 is configured to restore and reproduce proper tension and alignment between the knee joint compartments, and equivalent results may be achieved using alternative fillers with comparable functionality. In some embodiments, the filler 5 may be combined with an adjustable or extendable filler portion 52. The filler portion 52 may include, for example, a miniature hydraulic or mechanical mechanism that allows the surgeon to fine-tune the spacing between the femur and tibia during surgery.15MOFO-358353868Atty. Docket No. 315172000140

[0068] The following describes an exemplary osteotomy method using osteotomy system 1.

[0069] (1) First, the surgeon performs distal femoral resection to prepare for implant placement. During this process, factors contributing to soft tissue tension around the knee joint — such as osteophytes on the femoral, tibial, or patellar sides — may be debrided (for example, debrided as much as possible).

[0070] (2) Next, the trial member 3 is installed on the femur. The surgeon selects a trial member corresponding to the patient and fits it against the femoral side with full surface contact in the flexed knee position. The trial member 3 may be customized to the patient, such as formed based on pre-operative imaging of the patient. In some examples, multiple trial members having assorted sizes and / or shapes are available to the surgeon during the surgery. The multiple trial members may be generalized for use with any patient or customized for the particular patient. As noted above, at least a portion of the trial member 3 is shaped in conformance with the intended femoral implant. As such, the trial member and femoral implant may be formed based at least partially on the same modeling of the desired anatomy for the patient. The trial member 3 is fixed to the femur by inserting its protrusions 32 into preformed holes in the femoral condyles.

[0071] (3) After the trial member 3 is installed, the surgeon may extend the knee joint (e.g., as fully as possible). At this point, gentle distal traction may be applied to the tibia A, although this is not mandatory. The surgeon also considers the appropriate stretching of the medial and lateral collateral ligaments (MCL and LCL) and performs traction, as necessary.

[0072] (4) The surgeon may select the appropriate filler 5 for the patient and insert the filler 5 between the trial member 3 and the tibia A. The filler 5 may be selected based on the desired joint space and ligament tension, and when inserted, may compensate for the joint space and to realign the tibial articular surface to its pre-defect position. As a result, the original joint line can be accurately reproduced, enabling precise osteotomy and implant placement.

[0073] In some embodiments, the surgeon selects the appropriate filler 5 based on a variety of factors. Such factors may include range of motion (e.g., knee flexion, extension, extension lag, flexion contracture), joint stability (e.g., laxity, stress on femoral / tibial curvature, Lachman test), and the overall size and dimensions of the patient’s knee. In some cases, preoperative imaging such as X-rays or CT scans may be used to estimate the appropriate filler size. During surgery, the surgeon may try multiple filler sizes to determine the optimal16MOFO-358353868Atty. Docket No. 315172000140 configuration that restores natural joint space and achieves appropriate soft tissue tension. By using various fillers with different shapes, sizes, and thicknesses, the surgeon can fine-tune the selection to match the patient’s unique anatomical needs. The surgeon may evaluate joint stability, range of motion, and overall alignment with each filler size to determine the optimal option for anatomical restoration. Alternatively, computer-assisted surgical planning software may be used to automatically identify the most suitable filler based on a combination of imaging and kinematic data. For example, the filler selection may be optimized using a machine learning model trained on at least one of imaging data or kinematic information.

[0074] (5) The surgeon may perform provisional assembly of the cutting block 21 and at least a portion of the bracket system that interfaces with the cutting block 21 (e.g., the junction body 22). For example, a junction body 22 with an angle C appropriate for the patient may be selected (or, with a junction body having an adjustable angle C, the angle C may be set). The angle C controls the degree of posterior slope of the tibial osteotomy. As such, the surgeon may select a junction body 22 with an angle C that provides the desired posterior slope. Different junction bodies having different angles C may be available to the surgeon for selection by the surgeon during surgery. Alternatively, a junction body 22 with a desired angle C may be selected prior to the surgery (e.g., based on pre-operative imaging). In some examples, junction bodies are available with angles C ranging from 0 degrees to 30 degrees, 25 degrees, 20 degrees, or 10 degrees. In some examples, a kit includes junction bodies having angles C in a particular degree increment (e.g., 2 degrees) from a low value (e.g., 0 degrees, 2 degrees, 4 degrees, etc.) to a high value (e.g., 30 degrees, 25 degrees, 20 degrees, etc. ). A range of junction bodies (having different angles C) may be preselected prior to surgery based on the patient, and the surgeon may select from among the range of junction bodies during surgery. Optionally, a range of junction bodies in a kit is predetermined, without being specific to the patient. In some examples, only a single junction body 22 (having an angle C that has been predetermined as appropriate for the patient) is available to the surgeon.

[0075] The plate portion 222 of the junction body 22 may be inserted into the slot 21C of the cutting block 21 to connect the junction body 22 to the cutting block 21. The plate portion 222 may have a friction fit or a slip fit with the slot 21C.17MOFO-358353868Atty. Docket No. 315172000140

[0076] (6) Next, the surgeon installs the cutting guide 2 on the tibia. With the trial member 3 in place, the surgeon can visually assess the position and orientation of the tibial resection plane relative to the distal surface of the femur (as it will be after placement of the implant) based on the position and orientation of the slot 21C. This can enable the surgeon to confirm the distance from the most distal point of the femur and make adjustments as necessary. During this step, the knee may be placed in slight flexion. The bracket system 10 may be connected to the trial member 3. For example, the slit blade 23 may be inserted into the groove 3 A of the trial member 3. As noted above, the groove 3 A may be formed parallel to the planar regions 33A and 33B, which may be aligned with the distal femoral osteotomy surface such that the slit blade 23 is positioned parallel to the distal femoral osteotomy surface. This may achieve planar reproduction.

[0077] (7) The surgeon then secures the assembled unit of the junction body 22 and the cutting block 21 to the slit blade 23. With respect to the illustrated example, the slit blade 23 is inserted between the fastener 223 and the upper surface of the mounting portion 221, and the fastener 223 may be tightened.

[0078] Through the above steps, the slot 21C is positioned based on the trial member 3 installed on the femur so as to provide a predetermined amount of tibial resection at the upper end of the tibia A. This reproducibility is based on the positional relationship among the trial member 3, the cutting block 21, and the intended osteotomy plane. These components function integratively to enable precise resection of the tibia A and an appropriate resection volume.

[0079] (8) The surgeon inserts at least one pin or other attachment component through the pin hole(s) 21B of the cutting block 21 and into the tibia A to aid in temporarily securing the cutting block 21 to the tibia A. For example, one pin may be placed in each of two pin holes 2 IB. The pin may be sized to fit within the hole 2 IB so as to prevent movement of the cutting block 21 in the up-down direction (with respect to the figures). Positioning pins in two pin holes 2 IB may prevent cutting block 21 from rotating about an axis extending in the left-right direction (with respect to the figures). The elongated shape of the pin hole(s) 21B provides clearance with the pin(s) in the right-left direction, enabling lateral positional adjustment of the cutting block 21 and / or rotational adjustment of the cutting bock 21 about an axis extending in the up-down direction (with respect to the figures). By temporarily fixing the cutting block 21 using the pin holes 2 IB, the resection height that reproduces the18MOFO-358353868Atty. Docket No. 315172000140 tension of the medial and lateral collateral ligaments is defined, and therefore the filler 5 is removed from the joint space where it has been placed.

[0080] At this stage, the junction body 22 functions to ensure that the slot 21C, which defines the tibial osteotomy surface, is positioned at a predetermined orientation relative to the trial member 3. For example, the function body 22 positions the slot 21C at a predetermined angle (e.g., a zero-degree angle (i.e., parallel) or at a non-zero angle) to the distal femoral osteotomy surface in the coronal plane. Simultaneously, the junction body 22 defines the inclination angle of the slot 21C in the sagittal plane (e.g., relative to the distal femoral osteotomy surface), thereby determining the posterior slope of the tibial osteotomy.

[0081] (9) The surgeon then loosens the fastener 223 and detaches the junction body 22 from the cutting block 21 and the fixing portion 231 of the slit blade 23. The slit blade 23 is removed from the trial member 3.

[0082] (10) The surgeon may adjust the rotational position of the cutting block 21. Specifically, the cutting block 21 may be rotated relative to the tibia A in a plane nearly parallel to the transverse plane (i.e., about an axis extending in the up-down direction with respect to the figures) to reach the appropriate alignment to the tibia A. As noted above, this rotation is made possible by the elongated shape of the pin hole 21B. In some instances, no rotational adjustment is needed.

[0083] (11) Once the cutting block 21 is confirmed by the surgeon to be in the correct position, the cutting block 21 is fixed in place such that it is immobile with respect to the tibia A. The surgeon may insert fixation components (e.g., pins or screws) through the pin holes 21 A and may drive them into the tibia A, thereby immobilizing the cutting block 21 on the tibia. In the illustrated example, the pin holes 21 A are arranged in three levels — upper, middle, and lower — and may be spaced at desired intervals (e.g., 2mm) vertically. However, this arrangement of pin holes 21A is merely exemplary, and it will be understood by a person of skill in the art that various arrangements of pin holes 21A may be provided (e.g., depending on the size and / or shape of the cutting block 21). The surgeon may choose any of the levels of pin holes 21 A at the surgeon’s discretion. Optionally, pins used for permanent fixation are inserted parallel to each other within the same level. After securing the pins for permanent fixation in the tibia A, the two pins temporarily placed through 2 IB may be removed.19MOFO-358353868Atty. Docket No. 315172000140

[0084] The posterior slope angle presented by the slot 21C of the cutting block 21 (e.g., as determined by angle C of the junction body 22) may be checked by the surgeon. If the surgeon determines that the posterior slope angle should be adjusted, the posterior slope can be adjusted using an appropriate posterior slope cutting angle adjustment block, such as the posterior slope cutting angle adjustment block 1200 of FIGS. 12A and 12B. The posterior slope cutting angle adjustment block 1200 includes a slot 1202 that is analogous to slot 21C of cutting block 21 but that is angled 1204 so as to increase the posterior slope angle of the tibial osteotomy relative to that provided by the slot 21C of cutting block 21. Other posterior slope cutting angle adjustment blocks can be configured to reduce the posterior slope angle by including a negative value for angle 1204. The posterior slope cutting angle adjustment block 1200 may be available (e.g., in a kit available to the surgeon) in multiple angle variations (e.g., up to 30 degrees relative to the orientation of slot 21C in predetermined increments, such as 2 degree increments) for enabling the surgeon to select a desired posterior slope angle. The posterior slope cutting angle adjustment block 1200 may include one or more pin holes 1206 that are configured in the same arrangement as at least some of the pin holes of the cutting block 21 such that the posterior slope cutting angle adjustment block 1200 can be positioned at the same position on the tibia as the cutting block 21. Once the appropriate posterior slope cutting angle adjustment block 1200 is selected, the cutting block 21 is removed while leaving at least one pin (preferably at least two, more preferably, exactly two) fixed in place to the tibia A. The posterior slope cutting angle adjustment block 1200 is then mounted to the pin(s), with the pin(s) located in pin holes 1206 that correspond to the pin holes of the cutting block 21 within which the pin(s) were received. This allows the posterior slope to be adjusted while maintaining the same positioning and stability.

[0085] The tilt angle of the cutting block 21 (i.e., the slot 21C) relative to the transverse plane in the coronal view can be verified using the angle checker 4. This verification is performed by attaching the angle checker 4 to the cutting block 21. The rod 42 is aligned with the mechanical axis of the tibia A, and the surgeon reads the scale 41 A indicated by the indicator 42A to confirm the inclination angle of the slot 21C. This process is typically performed by positioning the tibia A vertically and allowing the rod 42 to hang vertically under gravity.

[0086] If the measured angle is determined by the surgeon to provide excessive inclination, an appropriate varus / valgus cutting angle adjustment block may be used for correction. An exemplary varus / valgus cutting angle adjustment block 1300 is illustrated in FIG. 13. The20MOFO-358353868Atty. Docket No. 315172000140 varus / valgus cutting angle adjustment block 1300 includes a slot 1302 that is angled in the coronal view relative to the slot 21C of the cutting block 21. Different configurations of varus / valgus cutting angle adjustment blocks having different angles of the slot 1302 (e.g., up to 30 degrees relative to the orientation of slot 21C in predetermined increments, such as 2 degree increments) may be available to the surgeon (e.g., in a kit) for different correction options. The slot 1302 of the varus / valgus cutting angle adjustment block 1300 is configured such that the innermost end of the slot 1302 (the left end of the slot 1302) is at the same position as the corresponding innermost end of the slot 21C of the cutting block 21 (the left end of the slot 21C) but extends laterally at a different angle than slot 21C, thereby allowing varus / valgus angle adjustment while maintaining equivalent positioning. The varus / valgus cutting angle adjustment block 1300 may include one or more pin holes 1306 that are configured in the same arrangement as at least some of the pin holes of the cutting block 21 such that the varus / valgus cutting angle adjustment block 1300 can be positioned at the same position on the tibia as the cutting block 21. Once the appropriate varus / valgus cutting angle adjustment block 1300 is selected, the cutting block 21 or the posterior slope cutting angle adjustment block 1200 is removed while leaving at least one pin (preferably at least two, more preferably, exactly two) fixed in place to the tibia A. The varus / valgus cutting angle adjustment block 1300 is then mounted to the pin(s), with the pin(s) located in pin holes 1306 that correspond to the pin holes of the cutting block 21 within which the pin(s) were received.

[0087] In some examples, a cutting angle adjustment block is configured to provide a combination of posterior slope angle adjustment and varus / valgus angle adjustment. Multiple different configurations of such cutting angle adjustment blocks, having multiple different combinations of posterior slope angle and varus / valgus angle, may be available to a surgeon (e.g., in a kit).

[0088] By appropriately setting the various angles of the portion that guides the tibial cutting tool (e.g., slot 21C of cutting block 21, slot 1202 of posterior slope cutting angle adjustment block 1200, or slot 1302 of varus / valgus cutting angle adjustment block 1300), the angle of the tibial osteotomy surface relative to the transverse plane can be optimized. This configuration allows adjustment of the tibial osteotomy angle and the resection volume according to the individual characteristics of the knee in full extension, thereby reducing the patient’s postoperative burden.21MOFO-358353868Atty. Docket No. 315172000140

[0089] (12) After the appropriate cutting block is selected and all adjustments are completed, the cutting block 21, posterior slope cutting angle adjustment block 1200, or varus / valgus cutting angle adjustment block 1300, may be further secured to the tibia A with additional pins as necessary, and the tibial osteotomy may be performed. In this step, the surgeon inserts a cutting tool into the slot 21C, slot 1202, or slot 1302 to cut the tibia A. As shown in the figures, since the slot extends longitudinally, the inserted cutting tool is positioned accurately along the intended osteotomy plane, enabling precise tibial resection.

[0090] Throughout the process above, the surgeon can assess the position and orientation of the tibial osteotomy prior to resection. Since the trial member is configured as a substantial substitute for the femoral implant, the surgeon can assess the location of the tibial osteotomy according to the most distal surface of the trial member — which replicates the thickness and geometry of the final implant. This allows the surgeon to evaluate soft tissue tension, including ligament stretch, in the extended position, and make appropriate adjustments (e.g., using a filler 5) and determine the tibial resection plane accordingly (including varus / valgus and posterior slope).

[0091] As described above, since the position of the slot 21C (or slot 1202 or slot 1302) and the resulting tibial osteotomy plane is determined via the groove 3A of the trial member 3C, the resection is performed at the appropriate location according to kinematic alignment. Furthermore, additional adjustments can be made at the discretion of the surgeon depending on the circumstances.

[0092] In some embodiments, the osteotomy system may incorporate a computer-assisted navigation system. This system may include optical or electromagnetic tracking sensors attached to key components such as the cutting block, trial member, and / or the patient's anatomical structures. The navigation system can provide real-time feedback on the positioning of components, the orientation of the cutting planes, and the depth of resection. This integration enhances the accuracy of the osteotomy procedure and enables intraoperative adjustments based on quantitative data.

[0093] A kit may include any of the components discussed above. For example, a kit may include a trial member and a cutting guide. The kit may include multiple junction bodies having different angles (e.g., angle C in FIG. 4C). The kit may include an angle measurement instrument, such as angle checker 4 of FIG. 9. The kit may include one or more22MOFO-358353868Atty. Docket No. 315172000140 posterior slope angle adjustment blocks, which may be a single block or a set of blocks having different posterior slope angles. The kit may include one or more varus / valgus angle adjustment blocks, which may be a single block or a set of blocks having different varus / valgus angles.

[0094] <Modification Example>Various shapes may be employed for the junction body 22. The junction body 22 may take the form of a blade, rod, bar, or hook. Accordingly, the plate portion 222 is not limited to a flat plate configuration.

[0095] (Clause 1) The osteotomy system 1 includes a trial member 3 that can be installed as a substitute for the implant at the distal femur, and a cutting guide 2 that is attachable and detachable from the trial member 3. The cutting guide 2 is provided with a slot 21C (serving as a guide portion) that, when the cutting guide 2 is mounted on the trial member 3, extends parallel to the distal femoral osteotomy surface in the coronal view and guides a tibial cutting tool.

[0096] In this clause, the distal osteotomy plane is used as a reference via the trial member 3, enabling the surgeon to accurately determine the tibial cutting position or angle in the extended position of the knee. This facilitates accurate alignment that respects the natural kinematics of the knee during total knee arthroplasty. As a result, postoperative patient satisfaction can be improved, and long-term implant stability can be ensured. By respecting the natural kinematics of the knee and establishing proper alignment based on the extended knee position, postoperative complications can be minimized.

[0097] In the extended knee position, the medial collateral ligament (MCL) is under uniform tension across its full attachment width on the bone, making it the most stable position in terms of ligament tension. In contrast, the lateral collateral ligament (LCL) tends to slacken in the flexed position due to its biomechanical properties, making it unreliable as a reference. However, even though some relaxation occurs in extension, both the MCL and LCL achieve their most uniformly tensioned and stable states in full extension. Therefore, by applying balanced traction to the tibia in this position (and / or using a filler) to evenly stretch both collateral ligaments, the distal femoral surface can be reliably used as a reference to guide a tibial osteotomy at a predetermined orientation to the distal femoral surface.23MOFO-358353868Atty. Docket No. 315172000140

[0098] Moreover, by using the systems and methods described herein, the distal femoral osteotomy surface can be precisely reproduced, allowing the surgeon to simulate the condition of the knee joint as it would appear after implant placement. This enables accurate assessment of the optimal tibial resection position.

[0099] (Clause 2) In Clause 1, the cutting guide 2 includes a slit blade 23 that extends parallel to the slot 21C in a front view and can be attached to a groove 3A. The trial member 3 is formed with the groove 3A (serving as a mounting portion), which allows the slit blade 23 to be installed in a manner that ensures it remains parallel to the distal femoral osteotomy surface when the trial member 3 is mounted on the femur.

[0100] (Clause 3) In Clause 1 or 2, the cutting guide 2 further includes a junction body 22 that is attachable and detachable relative to the slit blade 23 and to a cutting block 21 that both forms the slot 21C and is attachable and detachable with respect to the junction body 22.

[0101] In the above clause, the slot 21C can be positioned parallel to the distal femoral osteotomy surface via the junction body 22, enabling osteotomy to be performed at an angle suitable for the patient.

[0102] (Clause 4) In any of Clauses 1 through 3, the junction body 22 includes a plate portion 222 (corresponding to the mounting portion) that is attachable and detachable relative to the slot 21C and that is arranged parallel to the slit blade 23 when the slit blade 23 is attached to the junction body 22.

[0103] In the above configuration, the plate portion 222 is shaped to match the slot 21C, which facilitates the attachment and detachment of the junction body 22 relative to the slot 21C and enables accurate positioning of the slot 21C.

[0104] (Clause 5) In any of Clauses 1 through 4, the junction body 22 includes a plate portion 222 that is attachable and detachable relative to the slot 21C, and a mounting portion 221 for installing the slit blade 23. to the junction body 22 may be configured such that the plate portion 222 and the slit blade 23 are at a non-zero angle to one another (i.e., angle C of FIG. 4c is non-zero).24MOFO-358353868Atty. Docket No. 315172000140

[0105] In this configuration, the osteotomy position can be accurately set via the junction body 22. As a result, the posterior slope angle of the tibial osteotomy can be precisely defined.

[0106] (Clause 6) In any of Clauses 1 through 5, the junction body 22 is provided in multiple variations having different angles.

[0107] In the above clause, a cutting guide 2 with an angle tailored to the patient's anatomy can be manufactured. This allows osteotomy to be performed at an angle appropriate for the individual patient.

[0108] (Clause 7) In any of Clauses 1 through 6, the cutting block 21 is configured to receive a pin (corresponding to a fixation member) for temporary fixation to the tibia A. The cutting block 21 is further formed with a pin hole 2 IB, which has an elongated shape extending along the slot 21C.

[0109] In this clause, the cutting block 21 can be temporarily secured to the tibia A. Because the pin hole 21B is formed as an elongated slot extending laterally, it allows rotational adjustment of the cutting block 21 along the transverse plane. As a result, the position of the cutting block 21 can be easily adjusted.

[0110] (Clause 8) In any of Clauses 1 through 7, the system further includes an angle checker 4 (corresponding to a measurement instrument) that is detachably mounted to the junction body 22 and is configured to measure the formation angle of the slot 21C relative to the transverse plane of the tibia A.

[0111] In the above clause, the angle of the slot 21C relative to the transverse plane can be appropriately adjusted using the angle checker 4. This allows for customization of the tibial osteotomy angle and resection depth based on individual knee joint characteristics, thereby reducing the patient’s postoperative burden.

[0112] (Clause 9) In any of Clauses 1 through 8, the measurement instrument includes a scale portion 41 that is detachably connected to the cutting block 21, and a rod 42 that is swingably connected to the scale portion 41. The scale portion 41 is provided with a radial scale 41 A (e.g., graduations) or a display (corresponding to a display portion) indicating the angular position of the rod 42 relative to the scale portion.25MOFO-358353868Atty. Docket No. 315172000140

[0113] In the above clause, the simple structure allows for accurate reading of the angle and enables proper setting of the angle of the slot 21C relative to the transverse plane.

[0114] (Clause 10) In any of Clauses 1 through 9, the guide portion comprises the slot 21C through which the cutting tool can be inserted in the insertion direction.

[0115] In the above clause, by configuring the guide portion as the slot 21C, the cutting tool can be accurately guided to the intended position.

[0116] (Clause 11)The trial member 3 is configured to be installed as a substitute for an implant on the distal portion of the femur and includes a groove 3A that allows a cutting guide 2 for guiding a tibial cutting instrument to be detachably attached.

[0117] (Clause 12)In Clause 11, the cutting guide 2 is detachably mounted to the trial member 3 and is configured to guide a tibial cutting instrument at a predetermined position relative to the distal femoral osteotomy surface.

[0118] In the above clause, the distal femoral osteotomy surface serves as a reference via the trial member 3, allowing the surgeon to accurately identify the cutting position or angle of the tibia A in the knee extension position. This enables precise alignment that considers the natural kinematics of the knee in total knee arthroplasty. It enhances postoperative patient satisfaction and ensures long-term implant stability. By respecting the natural kinematics of the knee and using the knee extension position as a reference, proper alignment can be achieved while minimizing postoperative complications.

[0119] The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated.26MOFO-358353868Atty. Docket No. 315172000140

[0120] Although the disclosure and examples have been fully described with reference to the accompanying figures, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims.Finally, the entire disclosure of the patents and publications referred to in this application are hereby incorporated herein by reference.27MOFO-358353868

Claims

Atty. Docket No. 315172000140CLAIMS1. An osteotomy system comprising: a trial member configured to be installed as a substitute for an implant on a distal portion of a femur; and a cutting guide detachably attachable to the trial member, wherein the cutting guide is provided with a guide portion that guides a tibial cutting tool relative to the trial member.

2. The osteotomy system of claim 1, wherein the cutting guide includes a blade that is aligned with the guide portion in a coronal view, and wherein the trial member includes a mounting portion configured such that, when the trial member is installed on the femur, the blade can be attached to the trial member in parallel with a distal femoral osteotomy surface.

3. The osteotomy system of claim 2, wherein the cutting guide further comprises: a junction body configured to be attachable and detachable with respect to both the guide portion and the blade; and a cutting block comprising the guide portion and configured to be attachable and detachable with respect to the junction body.

4. The osteotomy system of claim 3, wherein the junction body includes a mounting portion that is attachable and detachable with respect to the guide portion, wherein the junction body is configured such that, when the blade is mounted to the junction body, the blade is positioned with respect to the guide portion at a predetermined angle in a plane that is parallel to a coronal plane.

5. The osteotomy system of claim 3, wherein the junction body includes: a first mounting portion that is attachable and detachable with respect to the guide portion; and a second mounting portion for attaching the blade at an angle relative to the mounting portion.28MOFO-358353868Atty. Docket No. 3151720001406. The osteotomy system of claim 5, comprising a plurality of junction bodies having a plurality of different angles.

7. The osteotomy system of claim 3, wherein the cutting block includes a slot extending along the guide portion and configured to receive an attachment component for attaching the cutting block to a tibia.

8. The osteotomy system of claim 1, further comprising a measurement instrument detachably mountable to the cutting guide, the measurement instrument being configured to measure an inclination of the guide portion with respect to a transverse plane of a tibia.

9. The osteotomy system of claim 8, wherein the measurement instrument includes: a scale portion detachably connected to the cutting guide; and a swingable member connected to the scale portion, wherein the scale portion is provided with markings indicating an angle of the swingable member relative to the scale portion.

10. The osteotomy system of claim 1, wherein the guide portion is a slot configured to allow insertion of a cutting tool in an insertion direction.

11. The osteotomy system of claim 1, comprising a filler configured to be positioned between the trial member and the tibia to control a position of a tibia relative to the trial member.

12. A trial member configured to be installed as a substitute for an implant on a distal portion of a femur, the trial member comprising a mounting portion to which a cutting guide, configured to guide a tibial cutting tool, is detachably attachable.

13. A cutting guide detachably attachable to the trial member of claim 12, the cutting guide being configured to guide a tibial cutting tool at a predetermined position relative to the trial member.29MOFO-358353868Atty. Docket No. 31517200014014. A tibial osteotomy system comprising: a trial member configured to be attached to a distal femoral osteotomy surface as a temporary substitute for an implant; and a cutting guide configured to mount to the trial member and guide a tibial cutting tool relative to the trial member.

15. The system of claim 14, wherein the cutting guide comprises a guide portion for receiving and guiding the tibial cutting tool, wherein the guide portion is oriented at a predetermined angle relative to the trial member when the cutting guide is mounted to the trial member.

16. The system of claim 15, wherein the predetermined angle is a zero-degree angle in a plane parallel to a coronal plane.

17. The system of claim 15, wherein the cutting guide comprises a cutting block that comprises the guide portion, wherein the cutting block is configured for attaching to a tibia.

18. The system of claim 17, wherein the guide portion is a slot, and the trial member comprises a slot for receiving a portion of the cutting guide for mounting the cutting guide to the trial member, wherein the slot of the cutting guide has a predetermined orientation with respect to the slot of the trial member when the cutting guide is mounted to the trial member.

19. The system of claim 17, wherein the cutting guide comprises a bracket system configured to attach to the cutting block and the trial member.

20. The system of claim 19, wherein the guide portion is a slot of the cutting block, and wherein a portion of the bracket system is received in the slot to attach the cutting block to the bracket system.

21. The system of claim 20, wherein the bracket system is configured to define a posterior slope of the tibial osteotomy.30MOFO-358353868Atty. Docket No. 31517200014022. The system of claim 15, comprising at least one cutting angle adjustment block that comprises a guide portion configured to guide the tibial cutting tool at a different orientation than the guide portion of the cutting block.

23. The system of claim 22, wherein the different orientation comprises at least one of a different posterior slope angle or a different varus / valgus angle.

24. The system of claim 14, comprising a filler configured to be positioned between the trial member and the tibia to control a position of a tibia relative to the trial member.

25. A kit comprising the tibial osteotomy system of claim 14, wherein at least one component of the cutting guide is provided in a plurality of different configurations.

26. The kit of claim 25, wherein the plurality of different configurations are configured to provide a plurality of different orientations of a cutting tool guide portion of the cutting guide relative to the trial member.

27. The kit of claim 26, wherein the plurality of different orientations comprises a plurality of different posterior slope angles.

28. The kit of claim 26, comprising at least one cutting angle adjustment block configured to provide different cutting angles in a plane parallel to a coronal plane.

29. The kit of claim 28, comprising an instrument for determining the cutting angle in the plane parallel to the coronal plane.

30. The kit of claim 25, comprising a filler configured to be positioned between the trial member and a tibia to control a position of a tibia relative to the trial member.

31. A method for tibial osteotomy comprising: attaching a trial member to a distal femoral osteotomy surface of a femur as a temporary substitute for an implant; mounting a cutting guide to the trial member to position the cutting guide relative to the trial member;31MOFO-358353868Atty. Docket No. 315172000140 attaching at least a portion of the cutting guide to a tibia; and cutting the tibia based on the position of the cutting guide relative to the trial member.

32. The method of claim 31, wherein the cutting guide comprises a cutting block, and wherein attaching the cutting guide to the tibia comprises attaching the cutting block the tibia.

33. The method of claim 32, wherein the cutting guide comprises a bracket system that attaches to the cutting block and the trial member, and wherein the method comprises removing the bracket system from the cutting block prior to cutting the tibia.

34. The method of claim 33, comprising after removing the bracket system from the cutting block and prior to cutting the tibia, further attaching the cutting block to the tibia.

35. The method of claim 34, comprising prior to further attaching the cutting guide to the tibia, adjusting an orientation of the cutting block while the cutting block is attached to the tibia.

36. The method of claim 32, wherein the cutting block is attached to the tibia via one or more attachment components, and method comprises removing the cutting block from the tibia and attaching a cutting angle adjustment block to the one or more attachment components.

37. The method of claim 36, wherein the cutting angle adjustment block is configured to provide a different orientation of a tibial osteotomy surface than the cutting block.

38. The method of claim 31, comprising inserting at least one filler between the trial member and the tibia to control a position of the tibia relative to the trial member and a tension of at least one ligament.32MOFO-358353868

Images