Unicompartment cutting block

Abstract

This disclosure provides a unicompartmental retrocompartment cutting block, its method of use, and a surgical component kit. The cutting block includes: a base capable of mounting on a resected proximal tibial surface of a patient's knee joint during use; and a body pivotally attached to the base. The body includes an alignment configuration arranged to align with markings on the femur during use. The body defines a cutting guide within the body for receiving cutting instruments to create a unicompartmental retrocompartmental incision in the femur. Moving the alignment configuration to align with the markings on the femur causes rotation of the body relative to the base and tilting of the cutting guide relative to the base. Different bases provide different incision locations, and rotation of the base provides further different incision locations.

Description

Technical Field

[0001] This disclosure relates to surgical instruments and methods, and more particularly to surgical instruments and methods for use in partial knee replacement surgery.

[0002] There are two general types of knee replacement surgery. The first is total knee replacement (TKR), in which both condyles and the entire proximal tibia are replaced with corresponding prosthetic components to replace the whole. The second is partial or unicompartmental knee replacement, in which only one condyle of the femoral condyle and the corresponding portion (medial or lateral portion) of the proximal tibia are replaced with corresponding prosthetic components.

[0003] One aspect of these two types of surgery is creating a tibial incision, which primarily defines the position of the tibial prosthesis component on the tibia, and a femoral incision, which primarily defines the position of the femoral prosthesis component relative to the femur. Typically, a cutting block is used to assist in creating these incisions and includes some kind of guide to help guide cutting instruments such as a powered bone saw or the like. The cutting block is attached to the bone at a location, and the location of the cutting block primarily defines the location of the incision; however, some cutting blocks may also include adjustment mechanisms to allow movement of the guide relative to the bone.

[0004] The location of the incision is a crucial factor in the success of knee replacement surgery, and there are many degrees of freedom involved, including the position of the tibial incision relative to the tibia, the position of the femoral incision relative to the femur, and the positions of the tibial and femoral incisions relative to each other.

[0005] The knee joint also includes various soft tissue structures, and the impact of prosthetic component placement on these structures must be considered. For example, if the resulting prosthetic knee joint results in excessive tension in the soft tissue structures, some surgeons perform soft tissue releases, such as ligament releases. In other cases, the soft tissues may be too loose, so surgeons may introduce pads or spacers to widen the knee joint space and increase tension in the soft tissue structures.

[0006] This disclosure relates to surgical instruments, equipment, component kits, and methods associated with unicompartmental knee arthroplasty, which can improve the ability to make femoral incisions taking into account the impact on soft tissue structures. Summary of the Invention

[0007] A first aspect of this disclosure provides a unicompartmental retrocutting block comprising: a base capable of being mounted in use on a resected proximal tibial surface of a patient's knee joint; and a body pivotally attached to the base, the body including an alignment configuration arranged in use to align with a mark on the femur, the body defining a cutting guide therein for receiving a cutting instrument to make a unicompartmental retrocutting in the femur, and wherein moving the alignment configuration to align with the mark on the femur causes the body to rotate relative to the base and causes the cutting guide to tilt relative to the base.

[0008] The main body can be connected to the base via a pivot that defines the axis of rotation.

[0009] The base may include a bending member, on which the body straddles during pivoting.

[0010] The bending member may have a non-constant radius of curvature. When the body straddles the bending member, the pivot may be able to translate relative to the base.

[0011] The bending member may have a first shoulder at a first end and a second shoulder at a second end.

[0012] The body may include a resilient biasing member arranged to maintain contact between the bending member and a portion of the body.

[0013] The body may include a fastener arranged to capture the curved member within a portion of the body.

[0014] The configuration may define an elongated slot extending along the slot axis. The slot axis may pass through the axis of rotation. The configuration may define, for example, a through-hole suitable for receiving a pin, such as an orifice with a circular cross-section.

[0015] The rear of the cutting block may define a first plane, and the cutting guide may define a second plane. The first plane and the second plane may face an acute angle of 80° or less. The acute angle may be 75°.

[0016] The body may define an opening extending through the body to receive a bone pin.

[0017] The base may include legs that allow it to be releasably attached to the tibial spacer.

[0018] The first aspect may include any of the features, options, and possibilities described elsewhere in this document (including in other aspects).

[0019] A second aspect of this disclosure provides a surgical instrument kit comprising: a unicompartmental posterior cutting block of the first aspect; and a tibial spacer including an attachment configuration arranged to engage by a foot of a base to allow the base to be releasably mounted on the tibial spacer.

[0020] The tibial spacer may have a longitudinal axis, and the attachment configuration may be further configured to allow the base to slide along the longitudinal axis of the tibial spacer.

[0021] The surgical instrument kit may also include multiple tibial spacers, each of which has a different thickness and / or different size corresponding to different tibial implants.

[0022] The tibial spacer may include a tibial spacer block, and the tibial spacer block may have a mark indicating the center line of the spacer block.

[0023] The surgical instrument kit may also include another unicompartmental posterior cutting block defining another cutting guide, wherein the other cutting guide is positioned to make a posterior incision in the femur at a position more anterior to the unicompartmental posterior cutting guide.

[0024] The surgical instrument kit may also include a unicompartmental distal cutting block having a distal cutting guide and another leg, wherein the unicompartmental distal cutting block is releasably mounted on the tibial spacer by means of the other leg engaging the attachment configuration of the tibial spacer.

[0025] The surgical instrument kit may also include another unicompartmental distal cutting block defining another distal cutting guide, wherein the other distal cutting guide is positioned in the femur to make a distal incision at a location more distal to the unicompartmental distal cutting guide.

[0026] The distal cutting block and the other distal cutting block may each include a rearwardly extending tail, wherein the tails each have a different thickness.

[0027] The second aspect may include any of the features, options, and possibilities described elsewhere in this document (including in other aspects).

[0028] A third aspect of this disclosure provides a method for creating a unicompartmental posterior femoral incision in a patient's knee joint, the method comprising: positioning a unicompartmental posterior cutting block on a resected proximal tibial surface of the tibia of the patient's knee joint and adjacent to a distal resected femoral condyle of the patient's knee joint, wherein the knee joint is in a flexed position, wherein the cutting block includes a base and a body, the body being rotatable relative to the base, and the body defining a cutting guide therein; aligning alignment features attached to the body with markings on the femur to rotate the body relative to the base; securing the body to the femur; and creating a posterior femoral incision using the cutting guide and a cutting tool.

[0029] The method may further include mounting the unicompartmental posterior cut block onto a tibial spacer, wherein the tibial spacer is placed on the surface of the resected proximal tibia.

[0030] Installing the cutting block on the tibial spacer may include: installing the cutting block on the tibial spacer at a first position; and moving the cutting block along the tibial spacer from the first position toward the femur.

[0031] The method may further include: selecting a unicompartmental posterior cutting block from a plurality of unicompartmental posterior cutting blocks, each of the plurality of unicompartmental posterior cutting blocks defining a corresponding cutting guide at a different position, the different positions corresponding to different anterior positions or different cutting ranges of the posterior incision, such as incision depth or incision height.

[0032] The method may further include: mounting a unicompartment distal cutting block onto a tibial spacer; and using the unicompartment distal cutting block to create a distal femoral incision.

[0033] The method may further include: selecting a unicompartmental distal cutting block from a plurality of unicompartmental distal cutting blocks, each of the plurality of unicompartmental distal cutting blocks defining a corresponding cutting guide at a different position, the different positions corresponding to different distal positions of the distal incision.

[0034] The method may further include: assessing the flexion knee joint gap between the posterior portion of the natural condyle of the femur and the proximal resection portion of the tibia with the knee flexed; assessing the extension knee joint gap between the distal portion of the natural condyle and the proximal resection portion of the tibia with the knee extended; and making a distal femoral incision at the distal location of the natural condyle, which would match the knee joint gap generated during extension with the flexion knee joint gap.

[0035] The method may further include: assessing the flexion knee joint gap between the posterior portion of the natural condyle of the femur and the proximal resection portion of the tibia with the knee flexed; assessing the extension knee joint gap between the distal portion of the natural condyle and the proximal resection portion of the tibia with the knee extended; and making the posterior femoral incision at the anterior position of the natural condyle, which would cause the knee joint gap generated in flexion to match the extension knee joint gap.

[0036] The method may further include placing the knee joint in excessive flexion before aligning the alignment feature.

[0037] The method may further include: marking a vertical line on the femur using a centerline on the tibial spacer when the knee joint is flexed and / or extended.

[0038] For example, another embodiment of the method may include: each of the plurality of unicompartmental retro-condylar cutting blocks includes a graphic marker indicating different cutting heights of the unicompartmental retro-condylar cutting block, and the method further includes: selecting a first unicompartmental retro-condylar cutting block including a first cutting guide and a first graphic marker, the first graphic marker indicating the cutting height of the first cutting guide; mounting the first unicompartmental retro-condylar cutting block on the tibial spacer; and moving the first unicompartmental retro-condylar cutting block to contact the femur. The method may include: the first graphic marker including one or more directional marker elements. For example, another embodiment of the method may further include: selecting a second unicompartmental retro-condylar cutting block including a second cutting guide and a second graphic marker, the second graphic marker indicating the cutting height of the second cutting guide, wherein the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide, and the second graphic marker indicates that the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide. Another embodiment of the method further includes:

[0039] Select a third unicompartmental post-cutting block comprising a third cutting guide and a third graphic mark, wherein the third graphic mark indicates the cutting height of the third cutting guide, wherein the cutting height of the third cutting guide is less than the cutting height of the first cutting guide, and the third graphic mark indicates that the cutting height of the third cutting guide is less than the cutting height of the first cutting guide.

[0040] For example, another embodiment of the method may provide: the cutting block has a front surface with an upper edge and a lower edge, and the direction marking element indicates a decrease in the cutting height when the direction marking element points to the lower edge of the cutting block. Another embodiment of the method may provide: the direction marking element indicates that the cutting height, for example, does not change relative to a reference cutting height, when the direction marking element is absent. Another embodiment of the method may provide: the direction marking element indicates an increase in the cutting height when the direction marking element points to the upper edge of the cutting block. Another embodiment of the method may provide: one or more cutting blocks provided with graphic markings also provide alphanumeric markings. Another embodiment of the method may provide: the alphanumeric markings indicate at least one other characteristic of the cutting guide compared to the characteristic indicated by the graphic markings. Another embodiment of the method may provide: the alphanumeric markings indicate an increase or decrease in the cutting height, or that the cutting height does not change. Another embodiment of the method may provide: the alphanumeric markings do not indicate an increase or decrease in the cutting height. Another embodiment of the method may provide: the graphic markings include one or more additional graphic marking elements, which are elongated elements, such as lines. For example, another embodiment of the method may provide: providing the direction marker element at one end of the additional graphic marker element or toward one end of the additional graphic marker element, and / or providing the alphanumeric marker at one end of the additional graphic marker element or toward one end of the additional graphic marker element. For example, another embodiment of the method may provide: the direction marker element includes vertices below the base of the triangle to indicate a decreasing triangle and / or vertices above the base of the triangle to indicate an increasing triangle.

[0041] The third aspect may include any of the features, options, and possibilities described elsewhere in this document (including in other aspects).

[0042] A fourth aspect of this disclosure provides a method for providing a prosthetic knee joint to a patient, the method comprising:

[0043] Provides a type of multiple cutting blocks;

[0044] Position the selected cutting block of this type near the patient's femur;

[0045] Guided by the selected cutting block, a portion of bone is cut away from the femur;

[0046] The method includes selecting the cutting block of the type from the plurality of cutting blocks of the type before positioning;

[0047] Each of the plurality of cut blocks of the aforementioned type has a configuration variable, and the configuration variable has a value;

[0048] The plurality of cut blocks of the aforementioned type include two or more cut blocks of the aforementioned type, the two or more cut blocks differing from each other in the value of the configuration variable;

[0049] Each of the two or more cut blocks of the type that differ from each other in the value includes one or more graphic markers, the one or more graphic markers indicating at least a portion of the value of the configuration variable for the respective cut block.

[0050] The graphic marker may include one or more direction marker elements.

[0051] One or more graphic markers may include a single direction marker element.

[0052] Direction marker elements can indicate an increase or decrease in a value or a portion of a value. Direction marker elements can indicate an increase or decrease in a value or a portion of a value relative to a reference value (e.g., zero). Direction marker elements can indicate no change in a value or a portion of a value relative to a reference value (e.g., zero). Direction marker elements can indicate no change in a value or a portion of a value relative to a reference value (e.g., zero) by not being present on a cut block. Direction marker elements may not indicate the amount by which a value or a portion of a value increases or decreases. Direction marker elements may not indicate the amount by which a value or a portion of a value increases or decreases relative to a reference value (e.g., zero).

[0053] When the cutting block has a configuration that cuts bone from the femur to reduce the gap between a portion of the femur and a portion of the tibia in at least one orientation relative to the femur, the value or a portion of the value represented by the graphic marker (particularly the direction marker element) may indicate a reduction in the value or a portion of the value. At least one orientation may include extension and / or flexion and / or hyperflexion.

[0054] When the cutting block has a configuration that cuts bone from the femur to maintain the gap between a portion of the femur and a portion of the tibia in at least one orientation relative to the femur unchanged, the value or a portion of the value represented by the graphic marker (particularly the orientation marker element) indicates that the value or a portion of the value has not changed. At least one orientation may include extension and / or flexion and / or hyperflexion.

[0055] When the cutting block has a configuration that cuts bone from the femur to increase the gap between a portion of the femur and a portion of the tibia in at least one orientation relative to the femur, the value or a portion of the value represented by the graphic marker (particularly the direction marker element) indicates an increase in the value or a portion of the value. At least one orientation may include extension and / or flexion and / or hyperflexion.

[0056] The method may include providing a plurality of cutting blocks, wherein the cutting blocks have a front end with an upper edge and a lower edge. The front end may be provided with a cutting slot through which a cutting element passes to cut bone.

[0057] Graphical markers, particularly directional marker elements, can indicate a reduction in the value or a portion of the value when the directional marker element points to the lower edge of the cut block. The directional marker element can be provided closer to the lower edge than the cut slot. The directional marker element can also be provided farther from the lower edge than the cut slot, for example, when the directional marker element extends from another graphic marker element.

[0058] Graphical markers, particularly directional marker elements, can indicate that the value or a portion of the value has not changed even when the directional marker element is absent.

[0059] Graphical markers, particularly directional marker elements, can indicate an increase in the value or a portion of the value when the directional marker element points to the upper edge of the cut block. The directional marker element can be provided closer to the upper edge than the cut slot. The directional marker element can be provided farther from the lower edge than the cut slot, for example, when the directional marker element extends from another graphic marker element.

[0060] Configuration variables can relate to the spacing between the cutting plane defined by this type of cutting block and the second plane. The second plane can be defined by a tibial spacer (e.g., below or above the spacer). The second plane can be defined by a surface of the tibia (e.g., the resected surface). Configuration variables can relate to the extension gap between the femur and tibia. Configuration variables can relate to the flexion gap between the femur and tibia.

[0061] The method may include one or more cut blocks provided with graphical markers, which are also provided with alphanumeric markers. The alphanumeric markers may indicate at least a portion of the value of the configuration variable for the corresponding cut block, such as another portion of the value, compared to the portion of the value indicated by the graphical markers. The alphanumeric markers may be numeric markers. The alphanumeric markers may indicate an increase or decrease in the value or a portion of the value, or indicate that the value or a portion of the value has not changed. The alphanumeric markers may indicate an increase or decrease in the value or a portion of the value relative to a reference value (e.g., zero). The alphanumeric markers may indicate no change in the value relative to a reference value. The alphanumeric markers may not indicate an increase or decrease in the value or a portion of the value relative to a reference value (e.g., zero).

[0062] Values ​​or portions of values ​​represented by alphanumeric markings (especially numerical markings) can be varying quantities. Values ​​or portions of values ​​can be expressed in mm. Multiple cutting blocks can provide a range of variations in values, for example, at 1 mm intervals. Values ​​or portions of values ​​represented by alphanumeric markings (especially numerical markings) can be varying quantities provided by cutting blocks having a structure that cuts bone from the femur to increase or decrease the gap between a portion of the femur and a portion of the tibia in at least one orientation relative to the femur, or to maintain that gap. At least one orientation can include extension and / or flexion and / or hyperflexion.

[0063] The graphic marker may include one or more additional graphic marker elements.

[0064] Other graphic marker elements can be, for example, elongated elements extending substantially parallel to the slots in the cutting block (such as the slots of a cutting element used to cut the femur), such as lines.

[0065] The direction marker element may be provided at one end of the additional graphic marker element or toward one end of the additional graphic marker element. Letter / number markers may be provided at one end of the additional graphic marker element or toward one end of the additional graphic marker element, such as the other end of the direction marker element.

[0066] At least a portion of the value may be a graphic marker indicating that the value is increasing and / or unchanged and / or decreasing. At least a portion of the value may be a graphic marker indicating that the value is increasing, wherein the graphic marker is a directional indication extending to one side of another graphic marker element (e.g., away from the slot receiving the cutting element). At least a portion of the value may be a graphic marker indicating that the value is decreasing, wherein the graphic marker is a directional indication extending to one side of another graphic marker element (e.g., toward the slot receiving the cutting element).

[0067] The direction marker element can be a triangle, for example, with its vertex below the base to indicate, for example, a decreasing triangle. The direction marker element can also be a triangle, for example, with its vertex above the base to indicate, for example, an increasing triangle.

[0068] Direction marker elements can be upward-pointing arrows. Direction marker elements can be downward-pointing arrows. Direction marker elements can be arrowheads, such as upward-pointing arrowheads or downward-pointing arrowheads.

[0069] Selection can include choosing one cut block of a certain type from two, three, four, or more cut blocks of that type. Selection can be provided based on a match between the values ​​of the cut block's configuration variables and the values ​​of the configuration variables of the cut blocks the user wishes to use in this method. Matching can be determined by the user examining the values ​​of the configuration variables. Matching can be determined by the user examining one or more graphical markers. Matching can be determined by the user examining one or more alphanumeric markers. Matching can be determined by the user examining one or more graphical markers and one or more alphanumeric markers. Values ​​can be a combination of one or more graphical markers and one or more alphanumeric markers.

[0070] The method may include selecting one cutting block of this type from a plurality of cutting blocks present on a surface and / or in a surgical instrument tray. The method may include one or more graphic markers and / or one or more alphanumeric markers that, during selection, are facing away from the surface and toward the user and / or away from the surgical instrument tray, for example, upwards.

[0071] This type of cutting block can be a first-type cutting block. A first-type cutting block can be a post-cutting block. A first-type cutting block can be a unicompartmental post-cutting block.

[0072] Configuration variables can relate to the spacing between the cutting plane defined by the first type of cutting block and the second plane. The second plane can be defined by a tibial spacer (e.g., below or above the spacer). The second plane can be defined by a surface of the tibia (e.g., the resected surface). Configuration variables can relate to the flexion gap between the femur and tibia.

[0073] A value can be one of a set of discrete values. This set of discrete values ​​can include a middle value and one or more lower values ​​and / or one or more higher values, which are the differences between the values.

[0074] The intermediate value can provide an intermediate level of relaxation when the knee is flexed, such as 1 mm of relaxation. The intermediate value can provide a cutting plane 7 mm to 8 mm (such as 7.5 mm or 7.7 mm) above the second plane (such as the upper surface of the tibial spacer).

[0075] One or more lower values ​​may provide a lower level of laxity during knee flexion, such as less than 1 mm. One or more lower values ​​may provide a cutting plane of less than 7.5 mm above the second plane, such as less than 7 mm, like 6.7 mm or less.

[0076] One or more higher values ​​can provide a higher level of laxity during knee flexion, such as greater than 1 mm of laxity, for example, 2 mm or greater. One or more higher values ​​can provide a cutting plane greater than 7.5 mm or greater than 7.7 mm above the second plane, for example, 8.5 mm or greater or 8.7 mm or greater.

[0077] The first type of cutting block can be positioned on the resected proximal tibial surface of the patient's knee joint and / or on the distally resected femoral condyle adjacent to the patient's knee joint. The knee joint can be in a flexed position.

[0078] The method may include using a posterior cutting block according to the first aspect. The method may include a first-type cutting block comprising a base and a body. The method may include a body rotatable relative to the base, and the body defining a cutting guide therein. The method may also include aligning alignment features attached to the body with markings on the femur to rotate the body relative to the base. The method may also include securing the body to the femur. The method may also include creating a posterior femoral incision using a cutting tool with the cutting guide.

[0079] This type of cutting block can be a second type of cutting block. A second type of cutting block can be a distal cutting block. A first type of cutting block can be a unicompartmental distal cutting block.

[0080] Configuration variables can relate to the spacing between the cutting plane defined by the second type of cutting block and the third plane. The third plane can be defined by a tibial spacer (e.g., below or above the spacer). The third plane can also be defined by a surface of the tibia (e.g., the resected surface). Configuration variables can relate to the degree of distalization of the femoral resection portion.

[0081] A value can be one of a set of discrete values. This set of discrete values ​​can include a base value and one or more lower values, which are the differences between the values.

[0082] Baseline values ​​can provide information about the surface repair of the femur. Baseline values ​​can provide information for femoral resection where the flexion and extension gaps are balanced or within an acceptable range, such as a difference of 0 mm to 2 mm. Baseline values ​​can provide a cutting plane 6.5 mm to 7 mm (e.g., 6.7 mm) above a third plane (such as the upper surface of the tibial spacer).

[0083] One or more lower values ​​can provide distalization for the femoral resection site. One or more lower values ​​can reduce the difference between the flexion and extension gaps. One or more lower values ​​can provide a cutting plane less than 6.5 mm above the second plane, for example, less than 6 mm for one cutting segment, less than 5 mm for another cutting segment, and less than 4 mm for yet another cutting segment.

[0084] The second type of cutting block can be positioned on the resected proximal tibial surface of the patient's knee joint and / or on the distally resected femoral condyle adjacent to the patient's knee joint. The knee joint can be in a flexed position.

[0085] This method may include using a distal cutting block, such as a unicompartmental distal cutting block. The distal cutting block may have a distal cutting guide and additional legs. The distal cutting block can be releasably mounted on the tibial spacer via additional legs that engage with attachment structures of the tibial spacer. The method may also include securing the distal cutting block to the femur. The method may further include creating a distal femoral incision using a cutting tool with the cutting guide.

[0086] This method may include using a second type of cutting block, and then using a first type of cutting block. Specifically, the method may include:

[0087] Position the second type of selected cutting block near the patient's femur;

[0088] A portion of bone was removed from the femur;

[0089] The method includes selecting a second-type cutting block from a plurality of second-type cutting blocks before positioning;

[0090] In the second type, each of the multiple cutting blocks has a configuration variable, and the configuration variable has a value;

[0091] The plurality of second-type cut blocks include two or more second-type cut blocks that differ from each other in terms of the values ​​of the configuration variables;

[0092] Two or more second-type cut blocks that are different from each other include one or more graphic markers that indicate at least a portion of the values ​​of configuration variables for the respective second-type cut blocks.

[0093] The method may also include using a first type of cutting block after using a second type of cutting block.

[0094] The method may also include following the use of a second type of cutting block:

[0095] Position the selected cutting block of type I near the patient's femur;

[0096] A portion of bone was removed from the femur;

[0097] The method includes selecting a first-type cutting block from a plurality of first-type cutting blocks before positioning;

[0098] Each of the multiple cutting blocks of the first type has a configuration variable, and the configuration variable has a value;

[0099] The plurality of first-type cut blocks include two or more first-type cut blocks that differ from each other in terms of the values ​​of the configuration variables;

[0100] Two or more first-type cut blocks that are different from each other include one or more graphic markers that indicate at least a portion of the values ​​of configuration variables for the corresponding second-type cut blocks.

[0101] For example, another embodiment of the method may include: each of the plurality of unicompartmental retro-condylar cutting blocks includes a graphic marker indicating different cutting heights of the unicompartmental retro-condylar cutting block, and the method further includes: selecting a first unicompartmental retro-condylar cutting block including a first cutting guide and a first graphic marker, the first graphic marker indicating the cutting height of the first cutting guide; mounting the first unicompartmental retro-condylar cutting block on the tibial spacer; and moving the first unicompartmental retro-condylar cutting block to contact the femur. The method may include: the first graphic marker including one or more directional marker elements. For example, another embodiment of the method may further include: selecting a second unicompartmental retro-condylar cutting block including a second cutting guide and a second graphic marker, the second graphic marker indicating the cutting height of the second cutting guide, wherein the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide, and the second graphic marker indicates that the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide. Another embodiment of the method further includes:

[0102] Select a third unicompartmental post-cutting block comprising a third cutting guide and a third graphic mark, wherein the third graphic mark indicates the cutting height of the third cutting guide, wherein the cutting height of the third cutting guide is less than the cutting height of the first cutting guide, and the third graphic mark indicates that the cutting height of the third cutting guide is less than the cutting height of the first cutting guide.

[0103] The fourth aspect may include any of the features, options, and possibilities described elsewhere in this document (including in other aspects).

[0104] A fifth aspect of this disclosure provides a posterior cutting block comprising: a base capable of being mounted in use on a resected proximal tibial surface of a patient's knee joint; and a body defining a cutting guide for receiving a cutting instrument to make a posterior incision in the femur; wherein the body has a configuration variable for positional characteristics of the cutting guide, and the configuration variable has a value; wherein the body includes one or more graphic markers indicating at least a portion of the values ​​of the configuration variable for a respective cutting block.

[0105] The cutting block may be a unicompartmental posterior cutting block. The cutting block may also include a body pivotally attached to a base. The cutting block may also include a body comprising an alignment configuration arranged to align with a mark on the femur during use. The cutting block may also provide that moving the alignment configuration to align with the mark on the femur causes the body to rotate relative to the base and causes the cutting guide to tilt relative to the base.

[0106] The fifth aspect may include any of the features, options, and possibilities set forth elsewhere in this document (including in other aspects and especially in the fourth aspect).

[0107] A sixth aspect of this disclosure provides a unicompartment distal cutting block comprising: a base portion capable of being mounted in use on a resected proximal tibial surface of a patient's knee joint; and a body portion defining a cutting guide for receiving a cutting instrument to create a distal incision in the femur; wherein the body portion has configuration variables for positional characteristics of the cutting guide, and configuration segment variables having values; wherein the body portion includes one or more graphic markers indicating at least a portion of the values ​​of the configuration variables for a given cutting block.

[0108] The cutting block can be a unicompartmental distal cutting block.

[0109] The sixth aspect may include any of the features, options, and possibilities set forth elsewhere in this document (including in other aspects and especially in the fourth aspect).

[0110] A seventh aspect of this disclosure provides a surgical instrument kit comprising: a cutting block of the fifth aspect or a cutting block of the sixth aspect; and a tibial spacer including an attachment configuration arranged to engage by a leg of a base or base portion to allow the base or base portion to be releasably mounted on the tibial spacer.

[0111] The kit may also include cutting blocks according to the sixth or fifth aspect. The kit may include multiple first-type cutting blocks, such as rear cutting blocks, and / or multiple second-type cutting blocks, such as distal cutting blocks.

[0112] The seventh aspect may include any of the features, options, and possibilities set forth elsewhere in this document (including in other aspects and especially in the fourth aspect). Attached Figure Description

[0113] The implementation scheme will now be described in detail by way of example and in conjunction with the accompanying drawings, wherein:

[0114] Figure 1 A perspective view of a surgical instrument assembly used to create a unicompartmental posterior incision is shown.

[0115] Figure 2 It shows Figure 1 A perspective view of the base of the unicompartmental posterior cutting block of the device shown;

[0116] Figure 3 It shows Figure 2 Side view of the base shown;

[0117] Figure 4 It shows Figure 2 Front view of the base shown;

[0118] Figure 5 It shows Figure 1 A perspective view of the main body of the unicompartmental posterior cutting block of the device shown;

[0119] Figure 6 It shows Figure 5 A side view of the main body shown;

[0120] Figure 7 It shows Figure 5 Rear view of the main body shown;

[0121] Figure 8 It shows including Figure 2 The base and Figure 5 The rear view of the single-unit cut block of the main body component;

[0122] Figure 9 It shows the passage along line A-A' Figure 8 A perspective cross-sectional view of the cut block shown;

[0123] Figure 10 The front view of three cut blocks is shown, each cut block having a different body with a different offset corresponding to the rear cut;

[0124] Figure 11 It shows Figure 1A plan view of a tibial spacer of a certain size for the surgical instruments shown;

[0125] Figure 12 for Figure 11 A perspective view of a tibial spacer of a certain size shown in the figure;

[0126] Figure 13 A perspective view of the distal cut of a single condyle is shown;

[0127] Figure 14 It shows Figure 13 Front view of the cut block shown;

[0128] Figure 15 It shows Figure 13 A side view of the cut block shown;

[0129] Figure 16 A perspective view of a set of distal cutting blocks is shown, which are configured to produce the resulting distal incisions at different distal locations.

[0130] Figure 17 yes Figure 16 The diagram shows a perspective view of one of the distal cut blocks with a 3mm distal cut offset.

[0131] Figure 18 A flowchart illustrating a partial knee replacement surgery is shown, demonstrating how to create a unicompartmental retrocompartmental incision using the surgical instruments.

[0132] Figure 19 It shows in Figure 18 A perspective view of the distal cutting block assembly of the surgical instruments used during the method shown.

[0133] Figure 20 It shows in Figure 18 A perspective view of the posterior cutting block assembly of the surgical instruments used during the method shown;

[0134] Figure 21 A flowchart illustrating a partial knee replacement surgery is shown, along with another method for creating a unicompartmental retrocompartmental incision using surgical instruments; and

[0135] Figure 22a , Figure 22b and Figure 22c It is a front view of three additional cut blocks, each with a different offset corresponding to the back cut and different bodies with graphic and numerical markings.

[0136] In the various figures of the accompanying drawings, unless otherwise specified, similar items in different figures share common reference numerals. Detailed Implementation

[0137] Reference Figure 1 This image shows a perspective view of a surgical instrument assembly 100 for making a unicompartmental retrocompartmental incision during partial knee replacement surgery. Assembly 100 includes a cutting block 110 mounted on a tibial spacer 120. The cutting block 110 has two main components: a base 130 through which the cutting block is indirectly mounted on the resected tibia via the spacer block of the tibial spacer 120 during use; and a body 160 pivotally connected to the base, allowing the body to pivot or rotate relative to the base 130.

[0138] exist Figure 2 , Figure 3 and Figure 4 The base 130 is shown in the figure. Figure 2 A perspective view of the front of the base 130 is shown. Figure 3 A side view of the base is shown, and Figure 4 A front view of the base is shown. Figures 2 to 4 As can be seen, the base 130 generally has an arched form and includes a curved member 132 extending between the first side member or leg 134 and the second side member or leg 136. Each leg terminates with an inwardly pointing foot 138, 140. Each foot 138, 140 defines a corresponding rib 142, 144 for engaging a corresponding slot defined in the tibial spacer, as described in more detail below.

[0139] The base 130 also includes a transverse member 146 that spans the base and extends between the first leg 134 and the second leg 136. The transverse member 146 defines a cavity 148 therein, and this cavity is arranged to be part of a receiving pivot, as described in more detail below. The cavity 148 is defined by a curved closed end and a channel leading to the curved closed end. The cavity 148 is symmetrical about a central axis 149 along which the pivot can translate during use, as described in more detail below.

[0140] The curved member 132 has a complex shape. The central portion 150 has a slightly concave or arcuate portion relative to the adjacent portion of the curved member. The curved member typically has a shape defined by a spline and includes adjacent portions with a slightly increasing radius of curvature followed by a slightly decreasing radius of curvature, wherein the center of the radius of curvature falls on the center of the passage of the orifice. The upper surface 152 of the curved member 132 provides a cam surface over which a similarly shaped surface of the body rides during use. The curved member 132 also includes a first shoulder 154 and a second shoulder 156 located on either side of the central arcuate portion formed by the slightly decreasing radius of curvature. These shoulders help prevent the body from becoming trapped on the curved member when it pivots relative to the body.

[0141] like Figure 3 As can be seen, the plane behind the base is typically inclined relative to the plane defined by the cut guide slots or legs 138, 140. The acute angle formed between the base plane and the leg plane is approximately 75°.

[0142] exist Figure 5 , Figure 6 and Figure 7 The main body 160 is shown in the figure. Figure 5 A perspective view of the front of the main body 160 is shown. Figure 6 A side view of the main body is shown, and Figure 7 The rear view of the main body is shown.

[0143] An elongated member 162 extends from the upper end of the body 160 and defines a slot 164 within the body. The elongated slot 164 extends along its axis. As explained in more detail below, the slot 164 is used to set the correct amount of rotation of the cutting guide by aligning the slot parallel to the internal / external rotation line of the femoral condyle. A bone pin can then be inserted through the slot 164 and into the distally resected femur to fix the angle and prevent movement of the body. The body can be configured to rotate up to 6 degrees relative to the base in each direction, i.e., +6 degrees and -6 degrees relative to the central alignment position. Figure 22a , Figure 22b and Figure 22c As shown in the embodiment, a through-hole 504 may also be provided in the elongated member 162 instead of the elongated slot 164. The through-hole 504 serves the same purpose as receiving the bone pin once alignment is provided.

[0144] The lower portion 166 of the body 160 defines a slot 168 that passes through the body 160 and provides a cutting guide for receiving the saw blade during use to make a unicompartmental back cut. Figures 5 to 7 As shown, the lip 170 extends from the front 172 of the body and is flush with the lower surface of the slot 168 to facilitate blade insertion. In other embodiments, the lip 170 may be omitted, and alternatively, a recessed portion may again be provided adjacent to the opening of the slot 168 to assist blade insertion.

[0145] Hole 174 is defined by the central portion of body 160 and extends through the body to provide a pin hole for optionally receiving another bone pin if the surgeon requires additional pin options based on bone quality.

[0146] As shown in the rear of the main body Figure 7As best shown, the body 160 also includes an elastic biasing member in the form of a movable spring 176, arranged adjacent to a generally curved channel 178 defined in the rear portion of the body. The upper surface defining the curved channel 178 has a curved shape generally similar to the upper surface 152 of the curved member 132 of the base, such that when the body is received in the curved channel 178, the body can straddle the curved member. The movable spring 176 is arranged to act on the lower surface of the curved member to help eliminate backlash and provide rotational stability. A first threaded hole 180 is defined in the body, adjacent to and directly above the curved channel 178. A second threaded hole 182 is defined in the lower portion of the body below the slot 168.

[0147] Similar to the base, the plane of the body is inclined relative to the plane defined by the slot 168, and the inclination angle is the same as that of the base. Therefore, the acute angle between the plane of the body and the plane of the cutting guide slot can be approximately 75°.

[0148] Figure 8 A rear view of the unicompartmental rear cutting block 110 formed by the body 160 and the base 130 is shown, and Figure 9 The cutting block is shown along Figure 8 The perspective cross-sectional view of line A-A'. (See figure) Figure 9 As best shown, a first fastener 184, in the form of a threaded bolt with a head, is received within a first threaded hole 180 in the body, the bolt head 186 being positioned on the body and used to capture the bent member 132 within a bent channel 178 of the body 160. Figure 8 and Figure 9 The diagram also shows that the movable spring is compressed against the underside of the bending member to eliminate play between the body and the base, and to improve rotational stability by pressing the bending member against the body.

[0149] A second fastener 188, in the form of a threaded bolt with a head, is received within a second threaded hole 182 in the lower part of the body. The second fastener 188 is mounted on the base and provides a pivot with a pivot axis about which the body 160 can pivot or rotate relative to the base 130. Additionally, the second fastener 188 can translate within a channel along a central axis 149 (coinciding with line A-A'). Thus, the pivot axis defines the center of rotation of the body, and due to the non-constant radius of curvature of the bending member 132, the pivot axis can translate along the central axis 149 when the body rotates relative to the base. As described above, the shape of the bending member 132 takes into account the geometry of the femoral implant to be used, and the bending member also has a non-constant radius of curvature, which helps maintain the desired joint gap or spacing, as described in more detail below.

[0150] The body 160 described so far has a slot 168 at one location on this body, thereby creating a zero offset, i.e., 0 mm, in the femoral incision. That is, the resulting femoral incision will have no offset, and therefore the thickness of the femoral implant and the planned tibial component placed in this incision will create a specific knee joint space. Figure 10 As shown, the surgical instrument may include multiple cutting blocks 110, 112, and 114, each with a different femoral incision offset. For example, a first cutting block 110 using a base 130 and a body 160 can produce a 0 mm offset femoral incision height. A second cutting block 112 may use the same base 130 but a slightly different second body 190, which is generally similar to body 160, but in which the cutting guide slot 192 is shifted by approximately 1 mm relative to the body to provide a 1 mm offset femoral incision height. A third cutting block 114 may use the same base 130 but a slightly different third body 194, which is also generally similar to body 160, but in which the cutting guide slot 196 is shifted by approximately 2 mm relative to body 160 to provide a 2 mm offset femoral incision height.

[0151] Because the cutting guide slots of the second and third bodies remove approximately 1 mm and 2 mm more femur than the main bodies, respectively, cutting blocks using these bodies can be used if the surgeon determines that the soft tissue tension may otherwise be too great and therefore wants to introduce some relaxation into the soft tissue by increasing the interval between the proximal tibial incision and the posterior femoral incision. In other embodiments, more or fewer cutting blocks with different bodies may be provided, and / or different cutting blocks may provide other different incision offsets, and may also provide different amounts of offset, such as 0 mm, 2 mm, and 4 mm.

[0152] Figure 11 A plan view of the tibial spacer 120 of the surgical instrument is shown. Although in Figure 11 While it has a boomerang-shaped form, in other embodiments, the tibial spacer 120 may also have a linear or right-angled form. Figure 12 A perspective view of a tibial spacer 120 is shown. The tibial spacer 120 has a handle or arm portion 122, a first spacer block 124 at a first end, and a second spacer block 126 at a second end. Each spacer block 124, 126 generally has the same shape and size as the corresponding tibial implant or prosthesis.

[0153] Some tibial implants or prostheses typically have a base and a supporting surface, usually made of polymer or similar materials. The base can have varying thicknesses. Furthermore, tibial implants are often offered in different sizes, allowing for a closer fit to the patient's anatomy. Therefore, Figure 11 and Figure 12 The tibial spacer 120 shown has spacer blocks 124 and 126 of the same size, corresponding to the size of a minimum tibial implant. However, spacer blocks 124 and 126 have different thicknesses. For example, the first spacer block 124 may have a thickness of 7 mm (corresponding to the total thickness of the intended tibial implant), while the second spacer block 126 may have a thickness of 8 mm, corresponding to a tibial implant of the same size but with a larger base height. Therefore, the device may include multiple tibial spacers similar to tibial spacer 120, but with further different thicknesses, such as 9 mm and 10 mm, or 6 mm and 5 mm. Furthermore, the device may include multiple tibial spacers similar to tibial spacer 120, but with different sizes corresponding to other tibial implant sizes, and multiple different thicknesses for each implant size. Therefore, the device may include a set of tibial spacers with different thickness ranges and for each different implant size.

[0154] Figure 11 The tibial spacer 120 shown in Figure 11 It is symmetrical in the plane and therefore can be used for the left or right knee joint.

[0155] like Figure 11 As best seen in the middle, the middle portion 123 of the handle 122 is narrower, and then the handle develops into a protrusion 125, which thus has a laterally extending structure and defines corresponding slots 127, 129 on each side, which are arranged to receive the ribs 142, 144 of the legs 138, 140 of the base 130.

[0156] Furthermore, the upper surface of each spacer block includes a centerline mark, such as 121, which in the illustrated embodiment is in the form of a groove, and this centerline mark indicates the center of a tibial prosthesis of the same size as the spacer block. In other embodiments, the centerline mark 121 may take other forms, such as a ridge or rib, or some printed, laser-marked, or otherwise marked mark.

[0157] Figure 13 A perspective view of a unicompartmental distal cutting block 300 is shown, which can be provided as part of a surgical instrument kit and used in unicompartmental knee replacement surgery with the aforementioned distal cutting block. Figure 14 A front view of the unicompartmental distal cutting block 300 is shown, and Figure 15A side view of a unicompartment distal cutting block 300 is shown. The unicompartment distal cutting block 300 has a body 302 having a front end 304 and a rear end 306. A slot 308 is defined by the body and extends from the front end through the rear end, providing a distal cutting guide for receiving the saw blade during use. A recess 310 is defined in the front end, just above the opening of the slot, to aid in the insertion of the saw blade.

[0158] The first central aperture 312, the second aperture 314 leading to the first side, and the third aperture 316 leading to the second side are also defined by the body and extend through the body for receiving bone screws to fix the distal cutting block during use.

[0159] A pair of opposing, inwardly pointing legs 318, 320 extend from the lower surface 322 of the distal cutting block. The legs 318 and 320 are constructed and sized similarly to the legs of the posterior cutting block, allowing the distal cutting block to be mounted on the tibial spacer 120 in a manner similar to that of the posterior cutting block.

[0160] The tail portion 324 of the cutting block extends from the rear side of the body. The rear portion 306 is generally curved to approximate the curved shape of the anterior portion of a typical femoral condyle. Each side of the body defines recessed portions 326, 328, and multiple grooves are provided in the lateral surfaces of the body to facilitate gripping and manipulating the distal cutting block during use.

[0161] like Figure 15 As best shown, a portion of the sidewall 332 of the adjacent slot 308 of the body is cut off. This allows the saw blade to be manipulated within the slot 308 to cut into the transverse bone when the distal cutting block is provided in a single size, and therefore for larger femurs, the saw blade may need to pivot within the slot to cut through the entire distal portion of the femur.

[0162] Figures 13 to 15 The unicompartmental distal cutting block 300 shown has a slot 308 positioned relative to the lower surface 322 of the block located on the tibial spacer to produce a default or zero-offset distal incision height.

[0163] like Figure 16As shown, a series of distal cutting blocks 330 can be provided, each distal cutting block having a cutting guide slot positioned within the body at the same height relative to the lower surface, but with different thicknesses of the posterior tail portion resulting in different distal incision offsets. For example, the first distal cutting block may have a distal incision offset of 0 mm and corresponds to the unicompartmental distal cutting block 300. The second distal cutting block 340 may have a further distal incision offset of 1 mm, the third distal cutting block 342 may have a further distal incision offset of 2 mm, and the fourth distal cutting block 344 may have a further distal incision offset of 3 mm. The first to fourth distal cutting blocks are generally similar, except that the posterior tail portion of the second to fourth cutting blocks extends further than that of the first cutting block, and the thickness of the tail portion is increased by 1 mm, 2 mm, and 3 mm, respectively, to reduce the gap between the position of the upper surface of the tail portion (on which the distal femur will rest during use) and the height of the slot, thereby producing different distal incision offsets.

[0164] For example, Figure 17 A perspective view of the fourth distal cutting block 344 is shown. Due to the 3mm thickness of the rear tail 346 compared to the first cutting block, the upper surface 347 of the rear tail 346 is moved closer to the guide slot 348 by about 3mm, resulting in a 3mm distal cut offset.

[0165] Figure 18 A flowchart illustrating a partial knee replacement surgery 200 and including the method using the aforementioned surgical instruments is shown. Many general steps of the surgery are routine and are therefore omitted or briefly described so as not to obscure this disclosure. The surgery is generally the same for both medial and lateral partial knee joints.

[0166] The following is combined with Figure 18 The described surgical procedure 200 prioritizes the knee joint space during flexion rather than extension. The goal is to match the knee joint space measured during extension to that measured during flexion, and generally aims to restore the joint line to its pre-disease state. (See later...) Figure 21 The description is similar to another part of knee replacement surgery 400, but prioritizes the knee joint space during extension. The knee joint space during flexion is then matched with the knee joint space measured during extension, and the aim is generally to maintain the joint line of the diseased state.

[0167] Initially, surgeons may have used preoperative X-rays to plan the surgery in order to estimate the possible size and location of the tibial and femoral implants, as well as the possible thickness of the tibial implant.

[0168] Following any optional preoperative template and planning, at point 202, the surgeon makes an incision to open the patient's knee joint, thereby gaining access to the surgical site. After exposing the surgical site, the surgeon can assess the condition of the knee joint and the appropriate surgical procedure to be performed. Additionally, some preparations for the surgical site can be performed at point 202, such as removing any soft tissue structures that are not to be preserved.

[0169] At position 204, a tibia resection is performed. The tibia cutting block mounted on the tibia alignment guide can be used to create a partial proximal tibia resection portion, which is typically an L-shaped resection portion due to the transverse cutting and subsequent sagittal cutting.

[0170] At point 206, the knee joint is placed in 90° flexion, and the size of the tibial resection portion and the tibial prosthesis to be used are checked using one of the tibial spacers with appropriate size and thickness corresponding to the thickness of the tibial resection.

[0171] After tibia sizing at 206, the knee joint is kept flexed and a flexion gap is established at 208 using spacer blocks of the tibial spacer. Spacer blocks of varying thicknesses can be used with the implant size to create a flexion gap as close to approximately 1 mm as possible. For example, tibial spacers 208 can be provided with a thickness range from 7 mm to 11 mm at 1 mm intervals. The thickness of the spacer block represents the thickness of the tibial implant construction (tray and insert). For example, a flexion gap can be assessed as 7 mm. Tibial spacers can also be provided in a series of spacer blocks of different shapes and / or different areas. For example, six spacer blocks of different shapes and / or areas, each also provided with two, three, or four different thicknesses, to form a set of tibial spacers for use. Furthermore, with the knee joint flexed, the centerline marking 121 of the spacer block is marked as a vertical line on the femur, for example using methylene blue or diathermy.

[0172] After assessing the flexion gap at 208, the knee joint is placed in extension, and the extension gap is assessed at 210.

[0173] The order of assessment for flexion and extension gaps is not critical, and in other implementations, the extension gap may be assessed before the flexion gap. A tibial spacer block is used to establish the extension gap.

[0174] Surgeons can experiment with spacer blocks of varying thicknesses until they feel they have achieved roughly the same ligament tension. Furthermore, with the knee extended, centerline marking 121 is indicated on the femur as a vertical line, for example, using methylene blue or diathermy.

[0175] If the lateral gap is loose or the long leg alignment needs correction, the surgeon can use a thicker tibial spacer block to increase the lateral gap to establish proper balance. For example, the lateral gap can be established at 210 mm to be 8 mm.

[0176] At position 212, with the leg extended, the distal unicompartmental femoral dissection block 300 to be used needs to be selected. The distal femoral dissection block is discussed above regarding... Figures 13 to 17 It has been described.

[0177] Options for the unicompartmental distal slit block 300 include:

[0178] ● ZERO distal cut blocks for surface repair of the femur as presented; for example, in cases where the gaps are equal or the difference is less than 2 mm;

[0179] ●A series of additional cutting blocks used to distalize the femoral resection to restore pre-disease balance; for example, in cases where the extension gap is greater than the flexion gap, the correct cutting block can be used to close the extension gap to match the flexion gap or reduce the difference between the extension and flexion gaps.

[0180] ●Therefore, the options provided in this implementation are:

[0181] ○1 DOWN the distal cutting block to reduce the extension gap by 1 mm relative to the buckling gap;

[0182] ○2 DOWN the distal cutting block to reduce the extension gap by 2 mm relative to the buckling gap;

[0183] ○3 DOWN the distal cutting block to reduce the extension gap by 3 mm relative to the buckling gap.

[0184] Therefore, there are four far-side cut block options available in this example, but a wider range can be deployed.

[0185] For example, an appropriate offset is selected based on the difference between the assessed flexion gap (7 mm) and extension gap (8 mm), and this appropriate offset can be used to make a distal femoral incision for the condyle to be replaced. For example, since the extension gap has been assessed as 8 mm and the flexion gap has been assessed as 7 mm, a distal cutting block (1 distal cutting block) with a 1 mm more distal offset can be used at 212 to distalize the distal incision. Thus, a 1 mm offset distal cutting block 340 can be selected and attached to the 7 mm thick tibial spacer by engaging its legs in a slot in the tibial spacer and then sliding toward the tibial spacer block.

[0186] For example, in Figure 19 The image shows an assembly of the distal cutting block mounted on the tibial spacer, but... Figure 19The image shows a distal cut block with a 3mm offset, instead of the 1mm offset used in this example. The selected distal cut block is mounted on the tibial spacer, which is then mounted on the removed tibia and slid towards the anterior aspect of the natural condyle.

[0187] In other embodiments, the distal cut block can be mounted on the tibial spacer, and then the construct is inserted into the knee joint space and positioned on the resected tibia. The knee joint may need to be slightly flexed to ensure that the distal cut portion is parallel to the tibial cut portion.

[0188] With the correct distal cutting block selected and inserted, the distal tibial cutting block is then pinned in place using bone screws in one or more of the pinning holes of the first central hole 312, the second hole 314, and the third hole 316. The distal femoral incision can then be made with a bone saw in the knee extension position.

[0189] After the pin is removed, the distal cutting block and spacer can be removed, and the distal cutting block can be removed from the tibial spacer by sliding downwards, and then removed from the tibial spacer.

[0190] At position 216, the knee joint is moved into a hyperflexed state, for example, to a flexion angle of approximately 105°. If the knee joint is not in a hyperflexed state, it may be difficult to configure the posterior cutting block to allow for the creation of a posterior incision with a bone saw without the saw colliding with the cutting block.

[0191] Then, at 218, as above... Figures 1 to 10 As described, a suitable posterior cutting block 110 is selected and attached to the same tibial spacer used to make the distal incision (in this example, a 7 mm thick tibial spacer block) so that the cutting block is indirectly mounted to the removed tibial surface via the spacer 124.

[0192] Options for the unicompartmental distal slit block 300 include:

[0193] ●a 1 DOWN cut block, which can:

[0194] ○ Maintain the buckling gap after using the ZERO distal cutting block;

[0195] ●a ZERO cutting block, which can:

[0196] ○ After using the ZERO distal cutting block, open the buckling gap; or

[0197] ○ After using 1 DOWN, 2 DOWN or 3 DOWN distal cutting blocks, leave 1 mm of relaxation during buckling;

[0198] ●a 1 UP cutting block, which can:

[0199] ○ After using the ZERO distal cutting block, open the buckling gap;

[0200] For example, in the current example, since a 7mm flexion gap is required, a 0mm offset cutting block is selected and mounted on a 7mm thick tibial spacer block. Specifically, the base 130 is placed on the tibial spacer, and the ribs 142, 144 of the legs 138, 140 engage with slots 127, 129 on either side of the tibial spacer. The cutting block is then slid along the tibial spacer toward the distal femoral resection until the posterior portion of the cutting block adjoins the distal femoral resection, as shown. Figure 20 As shown in the figure, the component 250 of the cutting block 110 is located on the tibial spacer 120 and positioned adjacent to the distal resection portion (not shown) of the femur.

[0201] At 220, rotate the body of the cutting block by hand until the extension member 162 is aligned parallel to the previously made centerline mark and thus aligned with the rotation of the femur. A narrow slot can be used to help guide the rotation of the body until it is parallel to the previously made centerline mark on the femur.

[0202] At 222, the cutting block is pinned in place using a bone pin passing through slot 164 or through central aperture 174, or both. The extended slot 164 and the alignment aids in establishing the centerline markings also allow the surgeon to select preferred portions of bone for pinning if other portions are less suitable pinning sites.

[0203] Then at 224, a posterior femoral incision can be made using a bone saw guided by slot 168 of the cutting block. By rotating the body and thus the cutting slot of the cutting block to be perpendicular to the previously marked centerline, this helps ensure that the gap size during flexion will remain closer to the target 7mm value, regardless of internal rotation of the femur.

[0204] If the buckling gap is found to be too tight after completing the first incision, the posterior condyle can be recut. For example, to remove another 1mm:

[0205] ●If a cut is made using a 1 DOWN cutter block, it will be recut using a ZERO cutter block;

[0206] ●If a cut is made using a ZERO cutting block, it will be recut using a 1 UP cutting block;

[0207] Once the posterior incision is complete, the cutting block can be depinned and the tibial spacer and cutting block assembly can be removed from the knee joint. The surgery can then continue at 226 in the usual routine manner until the partial knee replacement is complete. Additional parts of the surgery may include femoral preparation through any oblique incisions required for the femoral implant, testing, keel preparation for the tibial implant, bone cement compression (for cemented implant systems), and finally, the insertion of the polymer support surface insert.

[0208] Figure 21 A flowchart is shown illustrating another unicompartmental knee replacement surgery 400, which is broadly similar to procedure 200 but prioritizes the extension gap. Many steps are broadly similar to those in the flexion gap-priority surgery 200 and will therefore not be described in detail.

[0209] After assessing the flexion gap at 408 (which could be, for example, 7 mm) and marking the vertical center line on the femur, assess the extension gap at 410 and again mark the vertical center line on the femur. For example, the extension gap could be assessed as 9 mm. Furthermore, the order of assessment for the flexion and extension gaps is not important and can be reversed. If the extension gap is loose or the long leg alignment requires further correction, a thicker spacer block can be used to increase the extension gap to establish proper balance.

[0210] At 412, in this example, a 0mm offset distal cut block and a ZERO distal cut block are selected and attached to a 9mm tibial spacer block inserted into the knee joint space. The knee joint may need to be slightly flexed to ensure the distal resection is parallel to the tibial incision. The distal cut block is pinned in place, and then a distal femoral incision is made at 414. The distal cut block is then removed, and the knee joint is again placed in hyperflexion at 416.

[0211] If the extension gap is loose, different distal cutting blocks can be selected to adjust the level of resection and the depth of bone removed; 1 DOWN, 2 DOWN and 3 DOWN will each be 1 mm smaller than the previous one because the block spacer thickness in each one is 1 mm larger than the previous one.

[0212] To select the posterior cutting block to use at 418, the difference between the extension gap and the flexion gap is used, in this case 9 mm minus 7 mm, approximately 2 mm. Therefore, a 2 mm offset posterior cutting block is selected to anteriorly position the posterior incision (i.e., move the posterior incision anteriorly) by approximately 2 mm. The posterior cutting block is then attached to the same 9 mm tibial spacer block and slid toward the dissected distal femur. The body of the cutting block is then rotated at 420 until the elongated slot 164 is parallel to the previously indicated vertical centerline. The posterior cutting block is then pinned in place at 422 using the elongated slot 164 and / or the central pin hole 174. The posterior femoral incision is then made at 424, and the remainder of the procedure can then be completed in the same manner as generally described above.

[0213] Compared to other posterior cutting blocks, using a pivotable cutting guide slot helps avoid unintended effects on soft tissue tension. For example, if the cutting block references the posterior femoral condyle, it will track this bone surface during any femoral rotation relative to the tibia (e.g., toward the tibia), potentially leading to unintended tightness in joint flexion, or away from the tibia, potentially leading to unintended laxity in joint flexion. Therefore, when internal rotation is applied, a pivotable cutting guide slot driven by the cam surface of a curved member already mounted on the resected tibia maintains the height of the posterior incision. This allows the surgeon's laxity preference to be maintained regardless of the amount of rotation they choose to apply. The posterior incision is typically parallel to the tibial resection portion expected during femoral rotation, thus preserving knee joint space dimensions.

[0214] For distal and rear cut blocks, the user must select from a set of options provided for that block. As mentioned above, the distal cut block options can include 0 mm, 1 mm, 2 mm, and 3 mm, where the mm value reflects the degree to which the cut is distalized. Similarly, as mentioned above, the rear cut block can provide 0 mm, plus 1 mm, and minus 1 mm options to control the applied relaxation. This is useful for the user to quickly and accurately determine which option to choose to achieve the desired effect.

[0215] Each instrument can be labeled with a numerical indicator of variance and a positive or negative sign indicating the nature of the variance. However, such a method is not as intuitive or clear as the initial choice of which incision to make. For example, does a positive marking relate to an incision further above the bone, or to an incision further below the bone, and thus remove more bone?

[0216] Embodiments of the present invention employ alternative methods instead of using values ​​and symbols (positive or negative). For example... Figure 16 As shown, a graphical marker 500 is provided to indicate the vector of change. This is accompanied by a numerical marker 502 indicating the degree of change.

[0217] Therefore, refer to Figure 16 This shows a set of distal cutting blocks from which the user can select. If the distal cutting block selection step 212 has been reached, then... Figure 18 In this method, the user has established the buckling gap through buckling gap assessment 208 and the extension gap through extension gap assessment 210. Once steps 408 and 410 have been completed to provide the assessment there, relative to... Figure 21 The method applies to similar locations. Based on the buckling and extension gaps, the user will remember the adjustments they want to achieve. For example, if the extension gap is larger than the buckling gap, the correct cutting block can be used to close the extension gap to match the buckling gap or reduce the difference between the extension and buckling gaps, relative to an acceptable variation.

[0218] For example, an acceptable variation could be from 0 mm to 2 mm, and the observed gap difference could be 3 mm, where the user decides to reduce the difference in gap by 2 mm. Therefore, the user needs to select the correct distal cutting block for the determined gap reduction.

[0219] Referring to the instrument tray or other locations where the distal cutting blocks of this group are set, clear indications and confirmations are provided to the user via graphic markings, where the numerical markings represent a reduction in gap difference. The graphic markings point downwards to indicate this reduction. This downward direction is clearly confirmed by adjacent numerical markings, which have an orientation easily understood by the user. Therefore, selecting the distal cutting block with the numerical marking 2 and the downward-pointing graphic markings in its message signifies that the user has selected the correct distal cutting block.

[0220] By providing numerical and graphic markings near the saw slot 308 during cutting, these markings are visible during their insertion gap and during the operational steps involved. Therefore, verification of the intended distal cutting block used can be provided at any time.

[0221] When positioned prior to selection, such as in an instrument tray, the distal cutting block can be positioned laterally to indicate the relative thickness of the spacer [in the cases of 1 DOWN, 2 DOWN, and 3 DOWN] or to indicate the absence of the spacer [in the case of ZERODOWN], to aid in selection, where the graphic and numerical markings are verified when lifted from the pre-use position. Alternatively, the distal cutting block can be oriented upwards to display the graphic and numerical markings.

[0222] After completing the distal resection Figure 18 214 and Figure 21In step 414, two alternative methods continue to the selection of the posterior cutting block, namely steps 218 and 418. Based on the assessment of the buckling and extension gaps, the nature of the distal resection portion, and whether to prioritize the buckling or extension gaps, the user will remember the adjustments they want to achieve. For example, the user may decide that the buckling and extension gaps already adjusted by the distal cutting block are as desired and do not require further adjustment.

[0223] For example, as a result of the aforementioned 2mm adjustment, the desired difference between the buckling and extension gaps will be restored to an acceptable range. In this case, further adjustments via the post-cut block are not required. (Refer to...) Figure 22a , Figure 22b and Figure 22c The set of post-cut blocks shown will make Figure 22b The ZERO post-cutting block was selected. The ZERO post-cutting block is configured not to provide further adjustment and has a 1 mm relaxation at buckling established in its construction.

[0224] As an alternative, if priority needs to be given to the extension gap, or if additional relaxation is required, an increase will be sought. In this case, the user will need to select an increased gap between the rear cutter block and the distal cutter block and / or the rear cutter block just used. Figure 22c This is an example of such a post-cut block. If the slack is too high, the user will need to select a post-cut block with a smaller gap; such as... Figure 22a As shown in the image.

[0225] Referring to the instrument tray or other locations of the cutting blocks after setting up the group, use graphic markings to clearly indicate and confirm to the user what the numerical markings indicate. A ZERO value numerical marking 502 and a non-existent graphic marking 500 pointing in either direction confirm that this is the correct option without further adjustment. A numerical marking 502 with a value of 1 and a downward-pointing graphic marking 500 confirm that this is... Figure 22a The example shows a reduction in the gap. This direction is downward, clearly indicated by the number 502, which is graphically linked to the graphic mark 500 via another graphic mark element 506, wherein the number 502 has an orientation easily understood by the user. Similarly, the value of the number 502 is 1 and the graphic mark 500 points upward ( Figure 22c This confirms that the gap has increased. Therefore, it is easier to select the desired post-cut block.

[0226] Additional graphic marker element 506 aids in interpreting the markings by providing a clear connection between the numerical markings 502 and the graphic markings 500. The additional graphic marker element 506 further reinforces the indication by which the graphic markings 500 indicate an increase or decrease relative to the cutting plane of the slot 168, extending parallel to the slot 168 and thus aligning with the changing cutting plane.

[0227] exist Figures 22a to 22c In this implementation, the numeric markers 502, graphic markers 500, and additional graphic marker elements 506 are recessed relative to the surrounding surface. This helps the user to see them clearly. Prominent markers and / or surface variations (such as surface texture) may be used to form or partially form the markers.

[0228] By providing numerical and graphic markings near the saw slot 168 during cutting, the numerical markings 502 and graphic markings 500 are again visible during their insertion gap and during the operational steps involved. Therefore, verification of the intended post-cut block used can be provided at any time.

[0229] When positioned before selection, such as in an instrument tray, the rear cutting block can be oriented with graphic mark 500 and number mark 502 facing upwards and thus highly visible during inspection.

[0230] In this specification, exemplary embodiments have been presented with respect to a selected set of details. However, those skilled in the art will understand that many other exemplary embodiments, including combinations of different selections of these details, can be practiced.

[0231] Unless a specific order is explicitly specified, any instructions and / or flowchart steps may be performed in any order. Furthermore, those skilled in the art will recognize that while a set of exemplary instructions / methods has been discussed, the material in this specification can be combined in various ways to produce other examples, and should be understood within the context provided by the specific implementation.

[0232] While this disclosure is open to various modifications and alternatives, its specific details have been shown and described in detail by way of example in the accompanying drawings. However, it should be understood that other embodiments besides the specific embodiments described are also possible.

Claims

1. A unicompartmental posterior cutting block (110), comprising: A base (130) that can be mounted on the surface of the resected proximal tibia of the patient's knee joint during use; and A body (160), pivotally attached to the base, the body (160) including an alignment configuration (164) arranged to align with a mark on the femur in use, the body (160) defining a cutting guide (168) for receiving a cutting instrument to make a unicompartmental retrofemoral incision in the femur, and wherein moving the alignment configuration (164) to align with the mark (121) on the femur causes the body (160) to rotate relative to the base (130) and causes the cutting guide (168) to tilt relative to the base (130).

2. The cutting block (110) according to claim 1, wherein the body is connected to the base by a pivot defining a rotation axis.

3. The cutting block (110) according to claim 2, wherein the base includes a bending member, and the body straddles the bending member when pivoting.

4. The cutting block (110) according to claim 3, wherein the bending member has a non-constant radius of curvature, and wherein the pivot is translatable relative to the base when the body straddles the bending member.

5. The cutting block (110) according to claim 3 or 4, wherein the bending member has a first shoulder at a first end and a second shoulder at a second end.

6. The cutting block (110) according to any one of claims 3 to 4, wherein the body includes an elastic biasing member arranged to maintain contact between the bending member and a portion of the body.

7. The cutting block (110) according to any one of claims 3 to 4, wherein the body includes a fastener arranged to capture the bending member within a portion of the body.

8. The cutting block (110) according to any one of claims 2 to 4, wherein the alignment configuration defines an elongated slot extending along the slot axis, and wherein the slot axis passes through the rotation axis, or wherein the alignment configuration is a through-hole.

9. The cutting block (110) according to any one of claims 1 to 4, wherein the rear of the cutting block defines a first plane and the cutting guide defines a second plane, and wherein the first plane and the second plane face an acute angle of less than 80°.

10. The cutting block (110) according to any one of claims 1 to 4, wherein the body defines an orifice extending through the body to receive a bone pin.

11. The cutting block (110) according to any one of claims 1 to 4, wherein the base includes a leg, the base being releasably attachable to the tibial spacer via the leg.

12. A surgical instrument kit, comprising: The unicompartmental posterior cutting block (110) according to claim 11; and Tibial spacer (120), the tibial spacer including attachment structures (127, 129) arranged to engage with the legs (138, 140) of the base (130) to allow the base to be releasably mounted on the tibial spacer (120).

13. The surgical instrument kit of claim 12, wherein the tibial spacer has a longitudinal axis, and wherein the attachment configuration is further configured to allow the base to slide along the longitudinal axis of the tibial spacer.

14. The surgical instrument kit of claim 12 or 13 further comprises a plurality of tibial spacers, wherein each tibial spacer has a different thickness and / or a different size corresponding to a different tibial implant.

15. The surgical instrument kit of any one of claims 12 or 13, wherein the tibial spacer comprises a tibial spacer block, and wherein the tibial spacer block has a mark indicating the centerline of the spacer block.

16. The surgical instrument kit according to any one of claims 12 or 13, further comprising: Another unicompartmental posterior cutting block, the other unicompartmental posterior cutting block defining another cutting guide, and wherein the other cutting guide is positioned to make a posterior incision in the femur at a position more anterior than the unicompartmental posterior cutting guide.

17. The surgical instrument kit according to any one of claims 12 or 13, further comprising: A unicompartmental distal cutting block having a distal cutting guide and another leg, wherein the unicompartmental distal cutting block is releasably mounted on the tibial spacer by means of the other leg engaging the attachment configuration of the tibial spacer.

18. The surgical instrument kit of claim 17, further comprising: Another unicompartmental distal cutting block, the other unicompartmental distal cutting block defining another distal cutting guide, wherein the other distal cutting guide is positioned to make a distal incision in the femur at a location more distal than the unicompartmental distal cutting guide.

19. The surgical instrument kit of claim 17, wherein the unicompartmental distal cutting block and the other unicompartmental distal cutting block each include a posteriorly extending tail, and wherein the tails each have a different thickness.

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