Single-piece cutting block

Abstract

A unicondylar posterior cutting block, method of use, and kit of surgical components are provided, the cutting block comprising: a base mountable in use on the resected proximal tibial surface of a patient's knee; and a body pivotally attached to the base, the body including an alignment formation positioned in use to align with a marking on the femur, the body defining a cutting guide therein for receiving a cutting instrument for making a unicondylar posterior cut on the femur, and wherein moving the alignment formation to align with the marking on the femur rotates the body relative to the base and tilts the cutting guide relative to the base. Different bases provide different cutting positions, and rotation of the base provides further different cutting positions.

Description

Technical Field

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

Background Art

[0002] There are two general types of knee replacement procedures. The first is a total knee replacement (TKR) procedure in which both femoral condyles and the entire proximal tibia are replaced with respective prosthetic components. The second is a knee partial replacement procedure or a unicompartmental knee replacement procedure in which only one of the femoral condyles and the corresponding portion (either the medial or lateral portion) of the proximal tibia are replaced with respective prosthetic components.

[0003] One aspect of both types of procedures is to perform a tibial cut that largely defines the position of the tibial prosthetic component on the tibia and a femoral cut that largely defines the position of the femoral prosthetic component relative to the femur. In many cases, cutting blocks are used to assist in making such cuts and include some type of guide to assist in guiding a cutting instrument such as a powered saw. The cutting block is attached to the bone at a position, and the position of the cutting block largely defines where the cut is to be made, although some cutting blocks can also include an adjustment mechanism that allows the guide to move relative to the bone.

[0004] Positioning of the cuts is an important factor in the success of knee replacement procedures, and there are a number of degrees of freedom including the position of the tibial cut relative to the tibia, the position of the femoral cut relative to the femur, and then the position of the tibial cut and the femoral cut relative to each other.

[0005] The knee joint also includes various soft tissue structures, and the influence of the positioning of prosthetic components on the soft tissue structures should also be considered. For example, some surgeons perform soft tissue release, such as ligament release, if the resulting artificial knee causes excessive tension on the soft tissue structures. In other cases, the soft tissue may be too lax, and the surgeon may introduce a shim or spacer to expand the knee gap and increase the tension of the soft tissue structures. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] The present disclosure is directed to surgical instruments, devices, kits of parts, and methods for knee joint unicompartmental replacement procedures that can improve the ability to perform femoral osteotomy taking into account the effects on soft tissue structures. MEANS FOR SOLVING THE PROBLEMS

[0007] A first aspect of the present disclosure is a unicondylar posterior cutting block, comprising a base that can be mounted on the resected proximal tibial surface of a patient's knee during use, and a body pivotally attached to the base, the body including an alignment formation arranged to be aligned with markings on the femur during use, the body defining internally a cutting guide for receiving a cutting instrument for performing a unicondylar posterior cut on the femur, and rotating the body relative to the base and tilting the cutting guide relative to the base by moving the alignment formation to align with the markings on the femur.

[0008] The body may be connected to the base by a pivot defining a rotation axis.

[0009] The base may include a curved member on which the body rides or cams when pivoting.

[0010] The curved member may have a non-constant radius of curvature. The pivot may be translatable relative to the base when the body rides or cams on the curved member.

[0011] The curved member may have a first shoulder at the first end and / or a second shoulder at the second end.

[0012] The body may include an elastically biasing member arranged to maintain contact between the curved member and a part of the body.

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

[0014] The forming part may define an elongated slot extending along the slot axis. The slot axis may pass through the axis of rotation. The forming part may define a through-opening, such as a circular cross-section opening suitable for receiving a pin.

[0015] The rear surface 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 form an acute angle of 80° or less. The acute angle may be 75°.

[0016] The body may define an opening extending therethrough for receiving a bone pin.

[0017] The base may include a foot that can releasably attach the base to the tibial spacer.

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

[0019] A second aspect of the present disclosure provides a kit of surgical instruments, comprising a single-piece posterior cutting block of the first aspect, and a tibial spacer including a mounting formation arranged to be engaged by a foot of the base so as to enable the base to be releasably mounted on the tibial spacer.

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

[0021] The kit of surgical instruments may further comprise a plurality of tibial spacers, each tibial spacer having a different thickness and / or a different size corresponding to tibial implants of different sizes.

[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 kit of surgical instruments can further comprise a further single-piece posterior cutting block defining a further cutting guide, the further cutting guide being positioned to perform a posterior cut on the femur at a position anterior to the single-piece posterior cutting guide.

[0024] The kit of surgical instruments can further comprise a single-piece distal cutting block having a distal cutting guide and a further foot, the single-piece distal cutting block being releasably mountable on the tibial spacer by engagement of the further foot with the attachment formation of the tibial spacer.

[0025] The kit of surgical instruments can further comprise a further single-piece distal cutting block defining a further distal cutting guide, the further distal cutting guide being positioned to perform a distal cut on the femur at a position distal to the single-piece distal cutting guide.

[0026] The distal cutting block and the further distal cutting block may each include a rearwardly extending tail, each of the tails having a different thickness.

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

[0028] A third aspect of the present disclosure is a method for performing a single posterior cut on the femur of a patient's knee, comprising positioning a single posterior cut block in a flexed knee position on the resected proximal tibial surface of the patient's knee tibia and adjacent to the resected condyle distal to the patient's knee femur, the cutting block comprising a base and a body, the body being rotatable relative to the base, the body defining a cutting guide therein; aligning an alignment feature attached to the body with a marking on the femur and rotating the body relative to the base; fixing the body to the femur; and performing a posterior femoral cut using a cutting tool using the cutting guide.

[0029] The method may further include mounting the single posterior cut block on a tibial spacer, the tibial spacer being placed on the resected proximal tibial surface.

[0030] Mounting the cutting block on the tibial spacer may include mounting the cutting block on the tibial spacer in a first position and moving the cutting block along the tibial spacer from the first position towards the femur.

[0031] The method may further include selecting the single posterior cut block from a plurality of single posterior cut blocks, each of the plurality of single posterior cut blocks defining a respective cutting guide having a different position corresponding to a different cutting range such as a different anterior position of the posterior cut or a cutting depth or a cutting height.

[0032] The method may further include mounting a single distal cut block on the tibial spacer and performing a distal femoral cut using the single distal cut block.

[0033] The method may further include selecting the single distal cut block from a plurality of single distal cut blocks, each of the plurality of single distal cut blocks defining a respective cutting guide having a different position corresponding to a different distal position of the distal cut.

[0034] The method may further include evaluating a flexed knee gap between a posterior portion of the native femoral condyle and a proximal resection of the tibia in a flexed knee state, evaluating an extended knee gap between a distal portion of the native condyle and a proximal resection of the tibia in an extended knee state, and performing a distal femoral osteotomy at a distal position of the native condyle such that the obtained extended knee gap matches the flexed knee gap.

[0035] The method may further include evaluating a flexed knee gap between a posterior portion of the native femoral condyle and a proximal resection of the tibia in a flexed knee state, evaluating an extended knee gap between a distal portion of the native condyle and a proximal resection of the tibia in an extended knee state, and performing a posterior femoral osteotomy at a front position of the native condyle such that the obtained flexed knee gap matches the extended knee gap.

[0036] The method may further include over-flexing the knee before aligning the alignment feature.

[0037] The method may further include marking a vertical line on the femur when the knee is in a flexed state and / or an extended state using a center line on the tibial spacer.

[0038] For example, the method of a further embodiment may include that each of a plurality of single-piece posterior cutting blocks includes a graphical mark indicating a different cutting height of the single-piece posterior cutting block, selecting a first single-piece posterior cutting block including a first cutting guide and a first graphical mark indicating the cutting height of the first cutting guide, mounting the first single-piece posterior cutting block on a tibial spacer, and moving the first single-piece posterior cutting block to contact the femur. The method may include a first graphical mark including one or more directional mark elements. For example, the method of a further embodiment may further include selecting a second single-piece posterior cutting block including a second cutting guide and a second graphical mark 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 graphical mark indicates that the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide. For example, the method of a further embodiment of claims 46-48 may further include selecting a third single-piece posterior cutting block including a third cutting guide and a third graphical mark indicating 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 graphical mark indicates that the cutting height of the third cutting guide is less than the cutting height of the first cutting guide.

[0039] The method, for example, a further embodiment may provide a cutting block having a front face with an upper edge and a lower edge, and the direction-indicating element points towards the lower edge of the cutting block, so that the direction-indicating element indicates a decrease in the cutting height. The method, for example, a further embodiment may stipulate that the absence of a direction-indicating element indicates, for example with respect to a reference cutting height, that the cutting height remains unchanged. The method, for example, a further embodiment may stipulate that the direction-indicating element points towards the upper edge of the cutting block, so that the direction-indicating element indicates an increase in the cutting height. The method, for example, a further embodiment may provide one or more cutting blocks provided with graphical markings, where alphabetical / numerical markings are also provided. The method, for example, a further embodiment may stipulate that the alphabetical / numerical markings indicate at least a further characteristic of the cutting guide as compared to the characteristic indicated by the graphical marking. The method, for example, a further embodiment may stipulate that the alphabetical / numerical markings indicate the magnitude of an increase or decrease in the cutting height, or the constancy of the cutting height. The method, for example, a further embodiment may stipulate that the alphabetical / numerical markings do not indicate an increase or decrease in the cutting height. The method, for example, a further embodiment may stipulate that the graphical marking includes one or more further graphical marking elements, and the further graphical marking elements are elongated elements such as lines. The method, for example, a further embodiment may stipulate that the direction-indicating element is provided at or towards one end of the further graphical marking element, and / or the alphabetical / numerical marking is provided at or towards one end of the further graphical marking element. The method, for example, a further embodiment may stipulate that the direction-indicating element includes a triangle having a vertex below the base of the triangle to indicate a decrease, and / or a triangle having a vertex above the base of the triangle to indicate an increase.

[0040] The third aspect may include any of the features, options, and possibilities described elsewhere in this specification, including other aspects.

[0041] A fourth aspect of the present disclosure is a method for providing an artificial knee joint to a patient, comprising: providing a plurality of cutting blocks of a certain type; positioning a selected cutting block of the certain type adjacent to the patient's femur; resecting a portion of bone from the femur guided by the selected cutting block; the method including selecting a cutting block of a certain type from among the plurality of cutting blocks of the certain type prior to positioning; each of the plurality of cutting blocks of the certain type has a configuration variable, and the configuration variable has a value; the plurality of cutting blocks of the certain type includes two or more cutting blocks of the certain type having a difference in the value of the configuration variable with respect to each other; providing a method, wherein each of the two or more cutting blocks of the certain type having a difference in value with respect to each other includes one or more graphical marks indicating at least a part of the value of the configuration variable of each respective cutting block.

[0042] The graphical mark may include one or more direction mark elements.

[0043] One or more graphical marks may include a single direction mark element.

[0044] The direction mark element may indicate an increase or decrease in a value or a part of a value. The direction mark element may indicate an increase or decrease in a value or a part of a value with respect to a reference value, for example, a 0 value. The direction mark element may indicate an invariance of a value or a part of a value with respect to a reference value, for example, a 0 value. The direction mark element may indicate an invariance of a value or a part of a value with respect to a reference value, for example, a 0 value by the absence in the cutting block. The direction mark element may not indicate the magnitude of an increase or decrease in a value or a part of a value. The direction mark element may not indicate the magnitude of an increase or decrease in a value or a part of a value with respect to a reference value, for example, a 0 value.

[0045] When the cutting block is configured to cut bone from the femur so as to reduce the gap between a portion of the femur and a portion of the tibia in at least one orientation of the tibia relative to the femur, a value or a part of a value represented by a graphical mark, in particular by a direction mark element, may indicate a decrease in the value or the part of the value. The at least one orientation may include extension and / or flexion and / or hyperextension.

[0046] When the cutting block is configured to cut bone from the femur so as to keep the gap between a portion of the femur and a portion of the tibia unchanged in at least one orientation of the tibia relative to the femur, a value or a part of a value represented by a graphical mark, in particular by a direction mark element, may indicate the invariability of the value or the part of the value. The at least one orientation may include extension and / or flexion and / or hyperextension.

[0047] When the cutting block is configured to cut bone from the femur so as to increase the gap between a portion of the femur and a portion of the tibia in at least one orientation of the tibia relative to the femur, a value or a part of a value represented by a graphical mark, in particular by a direction mark element, may indicate an increase in the value or the part of the value. The at least one orientation may include extension and / or flexion and / or hyperextension.

[0048] The method may include providing a plurality of cutting blocks, the cutting blocks having a front face with an upper edge and a lower edge. The front face may be provided with a cutting slot through which a cutting element passes to cut bone.

[0049] By the direction mark element pointing towards the lower edge of the cutting block, a graphical mark, in particular the direction mark element, may indicate a decrease in the value or the part of the value. The direction mark element may be provided closer to the lower edge than the cutting slot. The direction mark element may be provided further away from the lower edge than the cutting slot, for example such that the direction mark element extends from a further graphical mark element.

[0050] A graphical mark, particularly a direction mark element, may indicate an invariant of a value or a part of a value by the absence of a direction mark element.

[0051] By the direction mark element pointing towards the upper edge of the cutting block, a graphical mark, particularly a direction mark element, may indicate an increase in a value or a part of a value. The direction mark element may be provided closer to the upper edge than the cutting slot. The direction mark element may be provided further away from the lower edge than the cutting slot, for example, such that the direction mark element extends from a further graphical mark element.

[0052] The configuration variable may be related to the distance between a cutting plane defined by a certain type of cutting block and a second plane. The second plane may be defined by a tibial spacer, for example, the lower surface or the upper surface of the spacer. The second plane may be defined by the surface of the tibia, for example, the resected surface. The configuration variable may be related to the extension gap between the femur and the tibia. The configuration variable may be related to the flexion gap between the femur and the tibia.

[0053] The method may include one or more cutting blocks provided with a graphical mark, where alphabetical / numerical marks are also provided. The alphabetical / numerical marks may indicate at least a part of the value of the configuration variable of each cutting block, for example, a further part of the value compared to a part of the value indicated by the graphical mark. The alphabetical / numerical mark may be a numerical mark. The alphabetical / numerical mark may indicate the magnitude of an increase or decrease of a value or a part of a value, or the invariance of a value or a part of a value. The alphabetical / numerical mark may indicate the magnitude of an increase or decrease of a value or a part of a value relative to a reference value, for example, a 0 value. The alphabetical / numerical mark may indicate the invariance of the magnitude relative to a reference value. The alphabetical / numerical mark may not indicate an increase or decrease of a value or a part of a value. The alphabetical / numerical mark may not indicate an increase or decrease of a value or a part of a value relative to a reference value, for example, a 0 value.

[0054] Alphabetical / numerical markings, particularly values or parts of values represented by numerical markings, may be magnitudes of change. The value or part of the value may be represented in mm. A plurality of cutting blocks may provide a series of different magnitudes of change, for example, at 1 mm intervals. The value or part of the value represented by alphabetical / numerical markings, particularly numerical markings, may be the magnitude of change provided by a cutting block having a configuration to cut bone from the femur so as to increase or decrease or leave unchanged the gap between a part of the femur and a part of the tibia in at least one orientation of the tibia relative to the femur. At least one orientation may include extension and / or flexion and / or hyperextension.

[0055] Graphical markings may include one or two or more additional graphical marking elements.

[0056] Additional graphical marking elements may be elongated elements such as lines extending substantially parallel to a slot within a cutting block, such as a slot for a cutting element used to cut the femur.

[0057] Direction marking elements may be provided at or towards one end of an additional graphical marking element. Alphabetical / numerical markings may be provided at or towards one end of an additional graphical marking element, such as at one end of a direction marking element.

[0058] At least a part of the value may be a graphical marking of whether the value is increasing and / or not changing and / or decreasing. At least a part of the value may be a graphical marking indicating that the value is increasing, and the graphical marking may be, for example, a direction indication extending along one side of an additional graphical marking element away from a slot for receiving a cutting element. At least a part of the value may be a graphical marking indicating that the value is decreasing, and the graphical marking may be, for example, a direction indication extending along one side of an additional graphical marking element towards a slot for receiving a cutting element.

[0059] The direction indication element may be, for example, a triangle, for example a triangle having a vertex below the base, to indicate a decrease. The direction indication element may be, for example, a triangle, for example a triangle having a vertex above the base, to indicate an increase.

[0060] The direction indication element may be an upward arrow extending upward. The direction indication element may be a downward arrow extending downward. The direction indication element may be an arrowhead such as an upward arrowhead extending upward or a downward arrowhead extending downward.

[0061] Selecting may include selecting one cutting block of a certain type from among two, three, four or more cutting blocks of that type. Selecting may be provided based on a match between the value of the configuration variable of the cutting block and the value of the configuration variable of the cutting block that the user wishes to use in the method. The match may be determined by the user inspecting the value of the configuration variable. The match may be determined by the user inspecting one or more graphical marks. The match may be determined by the user inspecting one or more alphanumeric marks. The match may be determined by the user inspecting one or more graphical marks and one or more alphanumeric marks. The value may be a combination of one or more graphical marks and one or more alphanumeric marks.

[0062] The method may include selecting one cutting block of a certain type from a plurality presented within the surface and / or the surgical instrument tray. The method may include, during selection, one or more graphical marks and / or one or more alphanumeric marks that face away from the surface and towards the user and / or outside the surgical instrument tray, for example facing upward.

[0063] The type of cutting block may be a first type of cutting block. The first type of cutting block may be a posterior cutting block. The first type of cutting block may be a single-piece posterior cutting block.

[0064] The configuration variable may be related to the distance between the cutting plane defined by the first type of cutting block and a second plane. The second plane may be defined by a tibial spacer, e.g., the lower surface or the upper surface of the spacer. The second plane may be defined by the surface of the tibia, e.g., the resected surface. The configuration variable may be related to the flexion gap between the femur and the tibia.

[0065] The value may be one of a discrete set of values. The discrete set of values may include an intermediate value and one or more lower values and / or one or more higher values, which are differences in values.

[0066] The intermediate value may provide a relaxation at an intermediate level in knee flexion, e.g., 1 mm of relaxation. The intermediate value may provide a cutting plane of 7 - 8 mm, such as 7.5 mm or 7.7 mm, above the second plane, such as the upper surface of the tibial spacer.

[0067] One or more lower values may provide a lower level of relaxation in knee flexion, e.g., less than 1 mm. One or more lower values may provide a cutting plane of less than 7 mm, such as less than 7.5 mm, e.g., 6.7 mm or less, above the second plane.

[0068] One or more higher values may provide a higher level of relaxation in knee flexion, e.g., relaxation exceeding 1 mm, e.g., 2 mm or more. One or more higher values may provide a cutting plane above 7.5 mm or above 7.7 mm, e.g., 8.5 mm or more or 8.7 mm or more, above the second plane.

[0069] The positioning of the first type of cutting block may be performed on the resected proximal tibial surface of the patient's knee and / or adjacent to the resected condyle distal to the femur of the patient's knee. The knee may be flexed.

[0070] The method may include the use of a posterior cutting block according to the first aspect. The method may include a first type of cutting block including a base and a body. The method may include a body rotatable relative to the base and a body defining a cutting guide therein. The method may further include aligning alignment features attached to the body with markings on the femur and rotating the body relative to the base. The method may further include fixing the body to the femur. The method may further include performing a posterior femoral cut using a cutting tool using the cutting guide.

[0071] The type of cutting block may be a second type of cutting block. The second type of cutting block may be a distal cutting block. The first type of cutting block may be a unicondylar distal cutting block.

[0072] The configuration variable may be related to the distance between the cutting plane defined by the second type of cutting block and a third plane. The third plane may be defined by a tibial spacer, e.g., the lower surface or the upper surface of the spacer. The third plane may be defined by the surface of the tibia, e.g., the resected surface. The configuration variable may be related to the degree of distalization for femoral resection.

[0073] The value may be one of a discrete set of values. The discrete set of values may include a base value and one or more lower values, which are differences in value.

[0074] The base value may provide femoral resurfacing. The base value may provide femoral resection where the flexion gap and the extension gap are balanced or within an acceptable range, e.g., a difference of 0 mm to 2 mm. The base value may provide a cutting plane of 6.5 to 7 mm, such as 6.7 mm, above a third plane such as the upper surface of the tibial spacer.

[0075] One or more lower values may provide distalization of the femoral resection. One or more lower values may reduce the difference between the flexion gap and the extension gap. One or more lower values may provide a cutting plane less than 6.5 mm above the second plane, e.g., less than 6 mm for one cutting block, less than 5 mm for another cutting block, and less than 4 mm for a further cutting block.

[0076] Positioning of the second type of cutting block may be performed on the resected proximal tibial surface of the patient's knee and / or adjacent to the resected condyle distally of the patient's knee femur. The knee may be flexed.

[0077] The method may include the use of a distal cutting block, e.g., a unicondylar distal cutting block. The distal cutting block may have a distal cutting guide and a further foot. The distal cutting block may be releasably attachable onto the tibial spacer by engagement of the further foot with the attachment formation of the tibial spacer. The method may further include fixing the distal cutting block to the femur. The method may further include performing a distal femoral cut using a cutting tool with the aid of a cutting guide.

[0078] The method may include the use of a second type of cutting block followed by the use of a first type of cutting block. Specifically, the method may include positioning a selected cutting block of the second type adjacent to the patient's femur, and excising a portion of bone from the femur. The method includes selecting a second type of cutting block from a plurality of second type of cutting blocks before positioning, Each of the plurality of second type of cutting blocks has a configuration variable, and the configuration variable has a value, The plurality of second type of cutting blocks includes two or more second type of cutting blocks that differ from each other with respect to the value of the configuration variable, Two or more second type of cutting blocks that differ from each other include one or more graphical marks indicating at least a part of the value of the configuration variable of each of the second type of cutting blocks.

[0079] The method may further include using a first type of cutting block after using the second type of cutting block.

[0080] The method, after using the second type of cutting block, positioning a selected first type of cutting block adjacent to the patient's femur, and further excising a part of the bone from the femur, may be further included, The method includes selecting a first type of cutting block from a plurality of first type of cutting blocks before positioning, Each of the plurality of first type of cutting blocks has a configuration variable, and the configuration variable has a value, The plurality of first type of cutting blocks includes two or more first type of cutting blocks that differ from each other with respect to the value of the configuration variable, Two or more first type of cutting blocks that differ from each other include one or more graphical marks indicating at least a part of the value of the configuration variable of each of the second type of cutting blocks.

[0081] For example, a method of a further embodiment may include that each of a plurality of single-piece posterior cutting blocks includes a graphical mark indicating a different cutting height of the single-piece posterior cutting block, selecting a first single-piece posterior cutting block including a first cutting guide and a first graphical mark indicating the cutting height of the first cutting guide, mounting the first single-piece posterior cutting block on a tibial spacer, and further moving the first single-piece posterior cutting block to contact the femur. The method may include a first graphical mark including one or more directional mark elements. For example, a method of a further embodiment may further include selecting a second single-piece posterior cutting block including a second cutting guide and a second graphical mark indicating the cutting height of the second cutting guide, the cutting height of the second cutting guide being greater than the cutting height of the first cutting guide, and the second graphical mark indicating that the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide. For example, a method of a further embodiment of claims 46-48 further includes selecting a third single-piece posterior cutting block including a third cutting guide and a third graphical mark indicating the cutting height of the third cutting guide, the cutting height of the third cutting guide being smaller than the cutting height of the first cutting guide, and the third graphical mark indicating that the cutting height of the third cutting guide is smaller than the cutting height of the first cutting guide.

[0082] A fourth aspect may include any of the features, options, and possibilities described elsewhere in this specification, including other aspects.

[0083] A fifth aspect of the present disclosure provides a posterior cutting block comprising a base mountable on the resected proximal tibial surface of a patient's knee during use and a body defining internally a cutting guide for receiving a cutting instrument for performing a posterior cut on the femur, the body having a configuration variable characteristic of the position of the cutting guide, the configuration variable having a value, and the body including one or more graphical marks indicating at least a part of the value of the configuration variable of each cutting block.

[0084] The cutting block may be a single-piece posterior cutting block. The cutting block may further include a body pivotally attached to a base. The cutting block may further include a body including an alignment formation arranged to align with markings on the femur during use. The cutting block may further provide for rotating the body relative to the base and tilting the cutting guide relative to the base by moving the alignment formation to align with markings on the femur.

[0085] The fifth aspect may include any of the features, options, and possibilities described elsewhere in this specification, including other aspects and particularly the fourth aspect.

[0086] A sixth aspect of the present disclosure provides a single-piece distal cutting block including a base section wearable on the resected proximal tibial surface of a patient's knee during use and a body section defining internally a cutting guide for receiving a cutting instrument for performing a distal cut on the femur, the body section having a configurable characteristic of the position of the cutting guide, the configuration variable having a value, and the body section including one or more graphical indicia indicative of at least a portion of the value of the configuration variable of each cutting block.

[0087] The cutting block may be a single-piece distal cutting block.

[0088] The sixth aspect may include any of the features, options, and possibilities described elsewhere in this specification, including other aspects and particularly the fourth aspect.

[0089] A seventh aspect of the present disclosure provides a kit of surgical instruments including a cutting block of the fifth aspect or a cutting block of the sixth aspect and a tibial spacer including an attachment formation arranged to be engaged by a foot of the base or base section to enable the base or base section to be releasably wearable on the tibial spacer.

[0090] The kit may further include a cutting block according to the other of the sixth or fifth aspect. The kit may include a plurality of cutting blocks of a first type, such as a rear cutting block, and / or a plurality of cutting blocks of a second type, such as a distal cutting block.

[0091] The seventh aspect may include any of the features, options, and possibilities described elsewhere in this specification, including other aspects and in particular the fourth aspect.

Brief Description of the Drawings

[0092] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings for illustrative purposes only.

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[0093] In the drawings, similar items in different drawings share a common reference numeral unless otherwise indicated.

DETAILED DESCRIPTION OF THE INVENTION

[0094] Referring to FIG. 1, a perspective view of an assembly 100 of surgical instruments for use in performing a single posterior cut during a knee joint replacement surgical procedure is shown. Assembly 100 includes a cutting block 110 mounted on a tibial spacer 120. Cutting block 110 has two main components, namely a base 130 that is indirectly mounted on the tibia where the cutting block is excised through the spacer block of tibial spacer 120 during use, and a body 160 that is pivotally connected to the base such that the body can pivot or rotate relative to the base 130.

[0095] Base 130 is shown in FIGS. 2, 3, and 4. FIG. 2 shows a front perspective view of base 130, FIG. 3 shows a side view of the base, and FIG. 4 shows a front view of the base. As seen in FIGS. 2 - 4, base 130 generally has the form of an arch and includes a curved member 132 extending between a first side member or leg 134 and a second side member or leg 136. Each leg terminates in an inwardly directed foot 138, 140. Each foot 138, 140 defines respective ribs 142, 144 for engaging respective slots defined within the tibial spacer, as will be described in more detail below.

[0096] Base 130 also includes a cross member 146 extending across the base between the first leg 134 and the second leg 136. Cross member 146 defines a cavity 148 therein and is arranged to receive a part of the pivot, as will be described in more detail below. Cavity 148 is defined by a curved closed end and a channel leading to the curved closed end. Cavity 148 is symmetric about a center line 149 and, as will be described in more detail below, the pivot can translate along it during use.

[0097] The curved member 132 has a complex shape. The central portion 150 has a slightly dish-shaped or arcuate portion relative to the adjacent portions of the curved member. The curved member generally has a shape defined by splines, including adjacent portions where the radius of curvature slightly increases and then the radius of curvature slightly decreases, and the center of the radius of curvature is on the center of the channel of the opening 148. The upper surface 152 of the curved member 132 provides a cam surface on which a surface of the same shape as the body rides during use. The curved member 132 also includes a first shoulder 154 and a second shoulder 156 on both sides of a central arcuate portion formed by a portion where the radius of curvature slightly decreases. These shoulders serve to prevent the body from moving relative to the curved member when the body pivots relative to the curved member.

[0098] As shown in FIG. 3, the plane of the back surface of the base is generally inclined with respect to the plane defined by the cutting guide slots or feet 138, 140. The acute angle formed between the plane of the base and the plane of the feet is about 75°.

[0099] The body 160 is shown in FIGS. 5, 6, and 7. FIG. 5 shows a front perspective view of the body 160, FIG. 6 shows a side view of the body, and FIG. 7 shows a rear view of the body.

[0100] The elongated member 162 extends from the upper end of the body 160 and defines a slot 164 therein. The elongated slot 164 extends along a slot axis. As will be described in more detail below, the slot 164 can be used to set the correct amount of rotation of the cutting guide by setting the slot parallel to the internal / external rotation line of the femoral head. A bone pin can then be inserted distally through the slot 164 into the femur with the distal end resected to fix the angle and prevent movement of the body. The body may be configured to rotate up to 6 degrees in each direction relative to the base, i.e., +6 degrees and -6 degrees relative to the central alignment position. As shown in the embodiments of FIGS. 22a, 22b, and 22c, it is also possible to provide a through opening 504 in the elongated member 162 instead of the elongated slot 164. The through opening 504 is used for the same purpose and is used to receive a bone pin after alignment has been performed.

[0101] 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 a saw blade during use to perform a unicondylar posterior cut. As shown in FIGS. 5-7, a lip 170 extends from the front face 172 of the body and is in the same plane as the lower surface of the cutting guide slot 168 to assist in the insertion of the blade. In other embodiments, the lip 170 may be omitted and instead a recessed section may be provided adjacent to the mouth of the cutting slot 168 to assist in the insertion of the blade.

[0102] The bore 174 is defined by the central portion of the body 160 and passes through to provide a pinning hole for optionally receiving a further bone pin if the surgeon requires further pinning options depending on the quality of the bone.

[0103] As best shown in Figure 7 showing the rear portion of the body, the body 160 also includes a resilient biasing member in the form of a live spring 176 disposed adjacent to a generally curved channel 178 defined in the rear portion of the body. The upper surface defining the channel 178 has a curved shape generally similar to the upper surface 152 of the base curved member 132 so that when the body is received within the curved channel 178, it can ride over the curved member. The live spring 176 is disposed to act against the lower surface of the curved member and helps to remove play and provide rotational stability. A first threaded bore 180 is defined in the body adjacent and directly above the curved channel 178. A second threaded bore 182 is defined in the lower portion of the body below the cut guide slot 168.

[0104] Similar to the base, the plane of the body is inclined by the same inclination angle as the base with respect to the plane defined by the cut guide slot 168. Thus, the acute angle defined by the plane of the body and the plane of the cut guide slot may be about 75°.

[0105] Figure 8 shows a rear view of the single-piece rear cutting block 110 formed from the body 160 and the base 130, and Figure 9 shows a perspective cross-sectional view of the cutting block along line A-A' of Figure 8. As best shown in Figure 9, a first fixture 184 in the form of a threaded bolt having a head is received within the first threaded bore 180 of the body, the head 186 of the threaded bolt seats against the body, and acts to capture the curved member 132 within the curved channel 178 of the body 160. As also shown in Figures 8 and 9, the live spring is compressed against the lower side of the curved member to remove play between the body and the base and improve rotational stability by biasing the curved member against the body.

[0106] The second fixture 188, in the form of a threaded bolt having a head 190, is received within a second threaded bore 182 in the lower portion of the body. The second fixture 188 seats on the base and provides a pivot having a pivot axis about which the body 160 can pivot or rotate relative to the base 130. Also, the second fixture 188 can translate along a central axis 149 (which coincides with line A-A') within the channel 148. Thus, the pivot axis defines the center of rotation of the body and, due to the non-uniform radius of curvature of the curved member 132, the body can translate along the axis 149 as it rotates relative to the base. The shape of the curved member 132 described above takes into account the geometry of the femur implant being used and has a non-uniform radius of curvature and serves to maintain a desired joint gap or spacing as will be described in more detail below.

[0107] The body 160 described thus far has a cutting guide slot 168 at a location on the body that results in a 0 offset femur cut, i.e., a 0 mm offset. That is, the resulting femur cut has no offset and thus, depending on the femur implant seated on that cut and the thickness of the planned tibial component, a particular knee gap results. As shown in FIG. 10, the surgical instruments may include a plurality of cutting blocks 110, 112, 114 each having a different femur cut offset. For example, a first cutting block 110 that uses the base 130 and the body 160 can result in a 0 mm offset femur cut height. A second cutting block 112 can use the same base 130 but has a second body 190 that is substantially the same as the first body 160 except that the cutting guide slot 192 is displaced by about 1 mm compared to the first body and provides a 1 mm offset femur cut height. A third cutting block 114 can use the same base 130 but has a third body 194 that is also substantially the same as the first body 160 except that the cutting guide slot 196 is displaced by about 2 mm compared to the first body 160 and provides a 2 mm offset femur cut height.

[0108] The positions of the cutting guide slots in the second and third bodies remove approximately 1 mm and 2 mm more femur than the first body, respectively. Thus, cutting blocks using these bodies may be used when the surgeon determines that otherwise the soft tissue tension may be too great, and thus desires to introduce some relaxation into the soft tissue by increasing the distance between the proximal tibia cut and the posterior femur cut. In other embodiments, more or fewer cutting blocks having different bodies may be provided, and / or different cutting blocks may provide other different cutting offsets, and different offset amounts, such as 0 mm, 2 mm, and 4 mm, may also be provided.

[0109] FIG. 11 shows a plan view of the tibial spacer 120 of the surgical instruments. Although having a boomerang shape in FIG. 11, the tibial spacer 120 may also have a straight or right-angled shape in other embodiments. FIG. 12 shows a perspective view of the tibial spacer 120. 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.

[0110] Partial tibial implants or prostheses generally have a base and a support surface often made of polymer or the like. The base may have different thicknesses. Also, different sized tibial implants are often provided so that the tibial implant can more closely conform to the patient's anatomical structure. Thus, the tibial spacer 120 shown in FIGS. 11 and 12 has spacer blocks 124 and 126 that are the same size and correspond to the size of the smallest 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 overall thickness of the intended tibial implant), while the second spacer block 126 may have a thickness of 8 mm corresponding to the same sized tibial implant but with a higher base height. Thus, the instruments may include multiple tibial spacers that are similar to the tibial spacer 120 but have further different thicknesses, for example, 9 mm and 10 mm, or 6 mm and 5 mm. Also, the instruments may include multiple tibial spacers that are similar to the tibial spacer 120 but have different sizes corresponding to other sizes of tibial implants and multiple different thicknesses for each implant size. Thus, the instruments may include a set of tibial spacers for each different implant size having a range of different thicknesses.

[0111] The tibial spacer 120 shown in FIG. 11 is symmetric in the plane of FIG. 11 and thus can be used for the left or right knee.

[0112] As best seen in FIG. 11, the middle portion 123 of the handle 122 is narrow, after which the handle extends laterally and develops into a raised portion 125 having formations that define respective slots 127, 129 in each side portion arranged to receive the ribs 142, 144 of the feet 138, 140 of the base 130.

[0113] Also, the upper surface of each spacer block is in the form of a groove in the illustrated embodiment and includes a centerline marking, such as 121, indicating the center of the tibial prosthesis of the same size as the spacer block. In other embodiments, the centerline marking 121 may take other forms, such as a ridge or rib, or in the form of some printed, laser-marked, or otherwise marked indicia.

[0114] FIG. 13 shows a perspective view of a unicondylar distal cutting block 300 provided as part of a kit of surgical instruments and usable in a unicondylar knee replacement procedure with the posterior cutting block described above. FIG. 14 shows a front view of the distal cutting block 300, and FIG. 15 shows a side view of the distal cutting block 300. The distal cutting block 300 has a body 302 with a front face 304 and a back face 306. A slot 308 is defined by the body and extends from the front face to the back face, providing a distal cutting guide for receiving a saw blade during use. A recess 310 is defined in the front face directly above the mouth of the slot to assist in inserting the saw blade.

[0115] A first, central opening 312, a second opening 314 to a first side, and a third opening 316 to a second side are also defined by the body and extend through the body for receiving bone screws to secure the distal cutting block during use.

[0116] A pair of opposing inwardly directed feet 318, 320 extend from the lower face 322 of the distal cutting block. The feet 318 and 320 are configured and dimensioned similar to the feet of the posterior cutting block such that the distal cutting block can be mounted on the tibial spacer 120 in a similar manner to the posterior cutting block.

[0117] A tail 324 of the cutting block extends from the rear side of the body. The back face 306 is generally curved to substantially reproduce the curved shape of the front portion of a typical femoral condyle. Each side face of the body defines recesses 326, 328, and a plurality of grooves are provided on the side faces of the body to facilitate gripping and handling of the distal cutting block during use.

[0118] As best shown in FIG. 15, portions of the side walls 330, 332 of the body adjacent to the slot 308 are cut away. This provides a distal cutting block in a single size so that a saw blade can be manipulated within the slot 308 to cut into the outer bone, and thus, in the case of a larger femur, it may be necessary to pivot the saw blade within the slot to cut through the entire distal portion of the femur.

[0119] The distal cutting block 300 shown in FIGS. 13-15 has a slot 308 positioned relative to a lower surface 322 that is located on the tibial spacer block, resulting in a default or 0-offset distal cutting height.

[0120] As shown in FIG. 16, a series of distal cutting blocks 330 may 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 rear tails resulting in different distal cutting offsets. For example, the first distal cutting block may have a 0 mm distal cutting offset and may correspond to the distal cutting block 300. The second distal cutting block 340 may have an additional 1 mm distal cutting offset, the third distal cutting block 342 may have an additional 2 mm distal cutting offset, and the third distal cutting block 344 may have an additional 3 mm distal cutting offset. The first through fourth distal cutting blocks are generally similar except that the rear tails of the second through fourth cutting blocks extend further than the rear tail of the first cutting block, with the tails having increasing thicknesses of 1 mm, 2 mm, and 3 mm, reducing the distance between the upper surface of the tail (on which the distal femur is placed during use) and the position of the slot height and resulting in different distal cutting offsets.

[0121] For example, FIG. 17 shows a perspective view of the fourth distal cutting block 344, which results in a 3 mm distal cutting offset due to the 3 mm thickness of the rear tail 346 that brings the upper surface 347 of the rear tail 346 approximately 3 mm closer to the guide slot 348 compared to the first cutting block 300.

[0122] FIG. 18 shows a knee joint partial replacement procedure 200 and shows a flowchart including the usage method of the above-described surgical instruments. Many of the overall steps of the procedure are as in the prior art and are therefore omitted or described briefly so as not to obscure the present disclosure. This procedure is generally the same for either the medial or lateral partial knee.

[0123] The procedure 200 described below in relation to FIG. 18 prioritizes the knee gap in flexion over the knee gap in extension. The knee gap in extension is made to match the gap measured in flexion and generally intends to return the joint line to its pre-disease state. A further knee joint partial replacement procedure 400 similar to the procedure 200 is described later with reference to FIG. 21 and prioritizes the knee gap in extension. The knee gap in flexion is then made to match the knee gap measured in extension and generally intends to maintain the joint line in the diseased state.

[0124] First, the surgeon may have generally planned the procedure using preoperative X-rays to estimate the possible sizes and positions of the tibial implant and the femoral implant, and also the possible thickness of the tibial implant.

[0125] After optional preoperative templating and planning, at 202, the surgeon makes an incision to open the patient's knee and access the surgical site. After exposing the surgical site, the surgeon may evaluate the condition of the knee and the appropriate procedure to use. Also, at 202, some preparation of the surgical site may be performed, such as removing any soft tissue structures that are not to be preserved.

[0126] At 204, a tibial resection is performed. A tibial cutting block mounted on a tibial alignment guide may be used to perform a proximal tibial resection that generally results in an L-shaped resection by a transverse cut and a subsequent sagittal cut.

[0127] At 206, place the knee in 90° flexion and use an appropriately sized tibial spacer having a thickness corresponding to the thickness of the tibial resection to confirm the tibial resection and the size of the tibial prosthesis to be used.

[0128] After sizing the tibia at 206, at 208, keep the knee in a flexed state and set the flexion gap using the spacer block of the tibial spacer. Different thickness spacer blocks may be used depending on the size of the implant to set the flexion gap to approximately the nearest 1 mm. For example, the tibial spacer 208 may be provided in thicknesses ranging from 7 mm to 11 mm at 1 mm intervals. The thickness of the spacer block represents the thickness of the tibial implant structure (tray and insert). For example, the flexion gap may be evaluated to be 7 mm. The tibial spacer may also be provided with spacer blocks of various different shapes and / or different areas. For example, spacer blocks of six different shapes and / or areas, each provided in two, three, or four different thicknesses, may be provided to form a set of tibial spacers for use. Also, with the knee flexed, the centerline mark 121 of the spacer block is marked as a vertical line on the femur, for example, using methylene blue or a diathermy mark.

[0129] After evaluating the flexion gap at 208, extend the knee and evaluate the extension gap at 210.

[0130] The order of evaluation of the flexion gap and the extension gap is not critical, and in other embodiments, the extension gap may be evaluated before the flexion gap. The tibial spacer block is used to set the extension gap.

[0131] The surgeon can work through spacer blocks of various different thicknesses until they feel that generally the same ligament tension has been achieved. Also, with the knee extended, the centerline mark 121 is marked as a vertical line on the femur, for example, using methylene blue or a diathermy mark.

[0132] If the extension gap is loose or the alignment of the long leg requires correction, the surgeon may increase the extension gap using a thicker tibial spacer block to establish the correct balance. For example, the extension gap may be set to 8 mm at 210.

[0133] At 212, with the leg extended, the distal femoral cutting block 300 to be used needs to be selected. The distal femoral cutting block has been described above in connection with FIGS. 13-17.

[0134] Options for the distal femoral cutting block 300 include the following. ● The ZERO distal cutting block used to resurface the femur as presented. For example, when the gaps are equal or the difference is less than 2 mm. ● A series of further cutting blocks used to distalize the femoral resection to restore the pre-disease balance. For example, when the extension gap is larger than the flexion gap, the correct cutting block can be used to close the extension gap to match the flexion gap or to reduce the difference between the extension gap and the flexion gap. ● Thus, the options provided in this embodiment are as follows. ○ The 1 DOWN distal cutting block for reducing the extension gap by 1 mm with respect to the flexion gap. ○ The 2 DOWN distal cutting block for reducing the extension gap by 2 mm with respect to the flexion gap. ○ The 3 DOWN distal cutting block for reducing the extension gap by 3 mm with respect to the flexion gap.

[0135] As a result, four distal cutting block options are selected in this example, but a wider range can be developed.

[0136] As an example, an appropriate offset may be selected based on the difference between the evaluated flexion gap (7 mm) and the extension gap (8 mm) and may be used to perform a distal femoral cut to the implant being replaced. For example, when the extension gap is evaluated to be 8 mm and the flexion gap is evaluated to be 7 mm, at 212, a 1 distal cut block, which is a distal cut block with a 1 mm distal offset, may be used to distalize the distal resection. Thus, a distal cut block 340 with a 1 mm offset may be selected, its foot engaged in the slot of the tibial spacer, and then slid toward the tibial spacer block and attached to the 7 mm thick tibial spacer.

[0137] For example, an assembly of distal cut blocks mounted on the tibial spacer is shown in FIG. 19, but a distal cut block with a 3 mm offset, rather than the 1 mm offset used in this example, is shown in FIG. 19. The selected distal cut block is mounted on the tibial spacer, while the tibial spacer is mounted on the resected tibia and slid toward the anterior portion of the native implant.

[0138] In other embodiments, the distal cut block may be mounted on the tibial spacer, and then the structure may be inserted into the knee gap, positioned on the resected tibia, and baked in place. It may be necessary to slightly flex the knee to ensure that the distal resection is parallel to the tibial resection.

[0139] Once the correct distal cut block is selected and inserted, the distal tibial cut block may then be pinned in place using bone screws at one or more of the pinning openings 312, 314, 316, and then a distal femoral cut may be performed using a bone saw with the knee in an extended position.

[0140] After removing the pins, the distal cut block and spacer may be removed. The distal cut block may be removed from the tibial spacer by sliding it downward and then removed from the tibial spacer.

[0141] At 216, the knee is moved into hyperextension, for example, to a flexion angle of about 105°. If the knee is not in a hyperextended state, it may be difficult to configure the posterior cutting block so that the bone saw can perform a posterior cut without hitting the cutting block.

[0142] Next, at 218, an appropriate posterior cutting block 110 is selected as described above in FIGS. 1 - 10 and attached to the same tibial spacer (in this example, a 7 mm thick tibial spacer block) used for performing the distal cut, whereby the cutting block is indirectly mounted on the resected tibial surface via the spacer 124.

[0143] Options for the posterior cutting block 300 include the following. ● A 1DOWN cutting block, which ○ Can maintain the flexion gap after using a ZERO distal cutting block. ● A ZERO cutting block, which ○ Can open the flexion gap after using a ZERO distal cutting block, or ○ Can leave a 1 mm relaxation in the flexed state after using a 1DOWN, 2DOWN or 3DOWN distal cutting block. ● A 1UP cutting block, which ○ Can open the flexion gap after using a ZERO distal cutting block.

[0144] For example, in this example, since a 7 mm flexion gap is required, a 0 mm offset posterior cut block 160 is selected and mounted on a 7 mm thick tibial spacer block. Specifically, the base 130 is positioned on the tibial spacer, and the ribs 142, 144 of the feet 138, 140 engage with the slots 127, 129 on both sides of the tibial spacer. Then, as shown in FIG. 20 showing the assembly 250 of the cut block 110 on the tibial spacer 120, the cut block 160 is slid along the tibial spacer toward the distal resection of the femur until the rear portion of the cut block abuts against the distal femoral resection, and is positioned adjacent to the distal resection of the femur (not shown).

[0145] In 220, the body of the cut block is rotated by hand until the extension member 162 is aligned parallel to the previously formed centerline marking and thus aligned with the rotation of the femur. The elongated slot may be used to assist in guiding the rotation of the body until it is parallel to the previously formed centerline marking on the femur.

[0146] In 222, the cut block is pinned in place using either a bone pin passing through the slot 164 or a bone pin passing through the central opening 174, or both. The extended slot 164 not only helps to establish alignment with the centerline marking, but also allows the surgeon to select the preferred portion of the bone to be pinned in cases where other portions are less favorable pinning sites.

[0147] Then, in 224, a posterior femoral cut may be made using a bone saw guided by the cut guide slot 168 of the cut block. By rotating the body and thus the cut slot of the cut block perpendicular to the previously marked centerline, this helps to ensure that the gap size during flexion remains as close as possible to the target value of 7 mm despite the internal rotation of the femur.

[0148] After the first cut is completed, if it is found that the flexion gap is too tight, posterior femoral recutting is possible. For example, if an additional 1 mm is to be removed, ● If a 1 DOWN cutting block is used to make the cut, a ZERO cutting block will be used to perform the recut. ● If a ZERO cutting block is used to make the cut, then a 1 UP cutting block will be used to perform the recut.

[0149] When the posterior cut is completed, the cutting block may be unpinned and the tibial spacer and cutting block construct may be removed from the knee. Next, at 226, the surgical procedure may be continued in a generally conventional manner until knee arthroplasty is completed. Further portions of the procedure may include completion of femoral preparation by performing any chamfer cuts required for the femoral implant, trialing, keel preparation for the tibial implant, cement pressurization (for a cement implant system), and finally polymer support surface inserts.

[0150] Figure 21 shows a flowchart depicting a further unicompartmental knee arthroplasty procedure 400 that is generally similar to procedure 200 but prioritizes the extension gap. Many of the steps are generally similar to those of the flexion gap priority procedure 200 and will not be described in detail again.

[0151] Following the assessment of the flexion gap 408, which may be, for example, 7 mm, and the marking of the vertical centerline on the femur, at 410 the extension gap is assessed and again evaluated with the vertical centerline marked on the femur. For example, the extension gap may be evaluated as 9 mm. Again, the order of assessment of the flexion gap and the extension gap is not critical and may be reversed. If the extension gap is loose or the alignment of the long leg requires further correction, a thicker tibial spacer block may be used to increase the extension gap and establish the correct balance.

[0152] At 412, in an example, the ZERO distal cut block, which is a 0 mm offset distal cut block, is selected and attached to a 9 mm tibial spacer block inserted into the knee gap. The knee may need to be slightly flexed to ensure that the distal resection is parallel to the tibial cut. The distal cut block is pinned in place, and then the distal femur cut is performed at 414. The distal cut block is then removed, and the knee joint is flexed again to an overflexed position at 416.

[0153] If the extension gap is loose, a different distal cut block can be selected to adjust the resection level and depth of the bone to be removed. 1 DOWN, 2 DOWN, and 3 DOWN each remove 1 mm less than the previous one because the thickness of the block shim is 1 mm larger than the previous one.

[0154] To select the posterior cut block to be used at 418, the difference between the extension gap and the flexion gap is used, which in this case is 9 mm minus 7 mm, which is approximately 2 mm. Thus, a 2 mm offset posterior cut block is selected to move the posterior resection forward by approximately 2 mm (i.e., move the posterior cut in the forward direction). The posterior cut block is then attached to the same 9 mm tibial spacer block and slid towards the resected distal femur. The body of the cut block is then rotated at 420 until the elongated slot 164 is parallel to the previously marked vertical centerline. The posterior cut block is then pinned in place at 422 using the elongated slot 164 and / or the central pinning opening 174. The posterior femur cut is then performed at 424, and the remaining procedures can then be completed in generally the same manner as described above.

[0155] Using a pivot cutting guide slot can help avoid unintended effects on soft tissue tension compared to other posterior cutting blocks. For example, if the cutting block references the femoral condyle, during any femoral rotation that moves the cutting block relative to the tibia, the cutting block follows this bone surface and, for example, moving it towards the tibia can result in an unexpected tightening of the joint during flexion or moving it away from the tibia can result in an unexpected loosening of the joint during flexion. Thus, a pivotable cutting guide slot driven by the cam surface of a curved member attached to the resected tibia maintains the height of the posterior cut when internal rotation is applied. Thus, the surgeon's relaxation preference can be maintained regardless of how much rotation the surgeon chooses to apply. The posterior cut is generally parallel to the tibial resection with the intended femoral rotation and thus the knee gap size is maintained.

[0156] For both the distal cutting block and then the posterior cutting block, the user must select from a provided set of options for that block. As described above, the distal cutting block options can include options of 0 mm, 1 mm, 2 mm, and 3 mm, and the mm values reflect the degree to which the cut is distalized. Also, as described above, the posterior cutting block can provide options of 0 mm, plus 1 mm and minus 1 mm to control the provided relaxation. It is useful for the user to be able to quickly and accurately determine which option to select to achieve the desired effect.

[0157] It is possible to mark each instrument with a numerical indication of the variation and a positive or negative sign to indicate the nature of the variation. However, such an approach is not as intuitive or clear as one might first think about what the selection is doing to the cut. For example, does a positive indication relate to a cut higher up on the bone or lower down and thus a cut that removes more bone?

[0158] Rather than using the display of values and signs [positive or negative], embodiments of the present invention take an alternative approach. As shown in FIG. 16, a graphical mark 500 indicating a vector of variation is provided. This is accompanied by a numerical mark 502 indicating the degree of variation.

[0159] Thus, referring to FIG. 16, a set of distal cut blocks is shown from which a selection is made by the user. When reaching the distal cut block selection step 212, in the methodology of FIG. 18, the user is establishing a flexion gap through the flexion gap evaluation 208 and an extension gap through the extension gap evaluation 210. Regarding the methodology of FIG. 21 as well, when steps 408 and 410 are completed and an evaluation is provided there, a similar position applies. Based on the flexion gap and the extension gap, the user has in mind the adjustment to be achieved. For example, if the extension gap is larger than the flexion gap for an acceptable variation, the correct cut block can be used to close the extension gap to match the flexion gap or to reduce the difference between the extension gap and the flexion gap.

[0160] For example, the acceptable variation may be 0 mm to 2 mm, the observed gap difference may be 3 mm, and the user decides to reduce the gap difference by 2 mm. Thus, the user needs to select the appropriate distal cut block for the determined gap reduction.

[0161] Referring to the instrument tray or other locations where a set of distal cut blocks is placed, the user is presented with a clear indication and confirmation by the graphical mark that the numerical mark is a reduction in the gap difference. The graphical mark points downward to indicate the reduction. This downward direction is clearly confirmed by an adjacent numerical mark having a direction that is easily understandable to the user. Thus, the selection of a distal cut block having a numerical mark 2 and a graphical mark that is downward in the information it conveys means that the user has selected the correct distal cut block.

[0162] By providing numerical and graphical markings adjacent to the slot 308 that receives the saw during cutting, the numerical and graphical markings can be seen during their insertion into the gap and during the operating steps to which they pertain. Thus, verification of the intended distal cutting block being used can be provided at any time.

[0163] Prior to selection, for example while positioned in the instrument tray, the distal cutting block may be positioned laterally to indicate the relative thickness of the spacer [in the case of 1 DOWN, 2 DOWN, 3 DOWN], or to indicate the absence of a spacer [in the case of ZERO DOWN] to assist in selection, and the graphical and numerical markings are verified when lifted from their pre-use position. Alternatively, the distal cutting block may be oriented to show the graphical and numerical markings upward.

[0164] After completion of the distal resection (214 in FIG. 18 and 414 in FIG. 21), both alternative methods proceed to the selection of the posterior cutting block (steps 218 and 418 respectively). Based on the evaluation of the flexion gap and the extension gap, the nature of the distal resection, and which of the flexion gap or the extension gap should be prioritized, the user has in mind the adjustment to be achieved. For example, the user may determine that the flexion gap and the extension gap adjusted by the distal cutting block are as desired and no further adjustment is necessary.

[0165] As an example, as a result of the 2 mm adjustment described above, the desired difference between the flexion gap and the extension gap would have been restored within an acceptable range. In that case, no further adjustment via the posterior cutting block is required. Referring to the set of posterior cutting blocks shown in FIGS. 22a, 22b, and 22c, this would result in the selection of the ZERO posterior cutting block of FIG. 22b. The ZERO posterior cutting block is configured not to provide further adjustment and its configuration incorporates a 1 mm relaxation during flexion.

[0166] Alternatively, if it is necessary to prioritize the extension gap, or if an increase in relaxation is otherwise required, an increase is requested. In that case, the user needs to select a rear cutting block with an increasing gap for the distal cutting block and / or for the rear cutting block used immediately previously. FIG. 22c is an example of such a rear cutting block. If the degree of relaxation is too high, the user needs to select a rear cutting block with a decreasing gap as shown in FIG. 22a.

[0167] Referring to the instrument tray or other locations where the set of rear cutting blocks is disposed, the user is presented with clear instructions and confirmation as to what the numerical markings are referring to by means of graphical markings. The absence of the numerical marking 502 of the ZERO value and the graphical marking 500 pointing in either direction confirms that this is the correct option for no further adjustment. The value of the numerical marking 502 being 1 and the graphical marking 500 being downward confirm that this is a decrease in the gap in the example of FIG. 22a. The fact that this direction is downward is clearly confirmed by the numerical marking 502 graphically linked to the graphical marking 500 by means of a further graphical marking element 506, and the numerical marking 502 has an orientation that is easily understandable to the user. Similarly, for FIG. 22c, the value of the numerical marking 502 being 1 and the graphical marking 500 being upward confirm that this is an increase in the gap. This facilitates the selection of the desired rear cutting block.

[0168] A further graphical marking element 506 aids in the interpretation of the markings by providing a clear connection between the numerical marking 502 and the graphical marking 500. The further graphical marking element 506 also reinforces that the graphical marking 500 indicates an increase or decrease with respect to the cutting plane of the slot 168 by means of a further graphical marking element 506 extending parallel to its slot 168, and thus coincides with the changing cutting plane.

[0169] In the embodiments of FIGS. 22a - 22c, the numerical indicia 502, the graphical indicia 500, and the further graphical indicia elements 506 are recessed with respect to the surrounding surface. This aids in clear visual recognition by the user. Surface variations such as raised displays and / or surface textures can be used to form or partially form the display.

[0170] By providing numerical and graphical indicia adjacent to the slot 168 that receives the saw during cutting, the numerical indicia 502 and the graphical indicia 500 can be seen again during their insertion into the gap and during the operating steps with which they are associated. Thus, verification of the intended rear cutting block being used can be provided at any time.

[0171] Prior to selection, for example while positioned within the instrument tray, the rear cutting block may be oriented with the graphical indicia 500 and the numerical indicia 502 facing upward, and thus be very visible during inspection.

[0172] In this specification, exemplary embodiments have been presented with respect to a selected set of detailed matters. However, those skilled in the art will understand that many other exemplary embodiments, including different sets of these selected detailed matters, may be practiced. The following claims are intended to cover all possible exemplary embodiments.

[0173] Unless a particular order is explicitly stated, any instructions and / or flowcharts can be executed in any order. Also, those skilled in the art will recognize that although one exemplary set of instructions / methods has been described, the content herein can be variously combined to yield other examples and should be understood within the context provided by this detailed description.

[0174] Although the present disclosure is suitable for various modifications and alternative forms, specific matters thereof have been shown in the drawings and described in detail for purposes of illustration. However, it should be understood that other embodiments are also possible in addition to the specific embodiments described. All modifications, equivalents, and alternative embodiments included within the scope of the appended claims are also included.

[0175] 〔Embodiment〕 (1) A single-piece posterior cutting block, comprising: a base that can be mounted on the resected proximal tibia surface of a patient's knee during use; and a main body pivotally attached to the base, the main body including an alignment forming portion arranged to be aligned with markings on the femur during use, the main body defining an internal cutting guide for receiving a cutting instrument for performing a single-piece posterior cut on the femur, and rotating the main body relative to the base and tilting the cutting guide relative to the base by moving the alignment forming portion to align with the markings on the femur. A single-piece posterior cutting block comprising a main body. (2) The cutting block according to Embodiment 1, wherein the main body is connected to the base by a pivot defining a rotation axis. (3) The cutting block according to Embodiment 2, wherein the base includes a curved member, and the main body rides on the curved member when pivoting. (4) The cutting block according to Embodiment 3, wherein the curved member has a non-constant radius of curvature, and the pivot can translate relative to the base when the main body rides on the curved member. (5) The cutting block according to Embodiment 3 or 4, wherein the curved member has a first shoulder at a first end and a second shoulder at a second end.

[0176] (6) The cutting block according to Embodiment 3 or 4, wherein the main body includes an elastically biasing member arranged to maintain contact between the curved member and a part of the main body. (7) The cutting block according to any one of embodiments 3 to 6, wherein the body includes a fixture arranged to capture the curved member within a part of the body. (8) The cutting block according to any one of embodiments 2 to 7, wherein the forming portion defines an elongated slot extending along a slot axis, the slot axis passing through the rotation axis or the forming portion being a through opening. (9) The cutting block according to any one of embodiments 1 to 8, wherein a rear surface of the cutting block defines a first plane, the cutting guide defines a second plane, and the first plane and the second plane form an acute angle of less than 80°. (10) The cutting block according to any one of embodiments 1 to 9, wherein the body defines a circular opening extending therethrough for receiving a bone pin.

[0177] (11) The cutting block according to any one of embodiments 1 to 10, wherein the base includes a foot, and the base is releasably attachable to the tibial spacer by the foot. (12) A kit of surgical instruments, the single-piece posterior cutting block according to 11, and a tibial spacer including an attachment formation arranged to be engaged by the foot of the base so as to enable the base to be releasably mounted on the tibial spacer. A kit of surgical instruments comprising a tibial spacer. (13) The kit of surgical instruments according to embodiment 12, wherein the tibial spacer has a longitudinal axis, and the attachment formation is further configured to enable the base to slide along the longitudinal axis of the tibial spacer. (14) The kit of surgical instruments according to embodiment 12 or 13, further comprising a plurality of tibial spacers, each tibial spacer having a different thickness and / or a different size corresponding to tibial implants of different sizes. (15) The kit of surgical instruments according to any one of embodiments 12 to 14, wherein the tibial spacer includes a tibial spacer block, and the tibial spacer block has a mark indicating a center line of the spacer block.

[0178] (16) Further comprising a further single-piece posterior cutting block defining a further cutting guide, wherein the further cutting guide is positioned to perform a posterior cut on the femur at a position anterior to the single-piece posterior cutting guide, the kit of surgical instruments according to any one of embodiments 12 to 15. (17) Further comprising a single-piece distal cutting block having a distal cutting guide and a further foot, wherein the single-piece distal cutting block is releasably attachable to the tibial spacer by the further foot engaging the attachment formation of the tibial spacer, the kit of surgical instruments according to any one of embodiments 12 to 16. (18) Further comprising a further single-piece distal cutting block defining a further distal cutting guide, wherein the further distal cutting guide is positioned to perform a distal cut on the femur at a position distal to the single-piece distal cutting guide, the kit of surgical instruments according to embodiment 17. (19) Each of the distal cutting block and the further distal cutting block includes a tail extending rearwardly, and each of the tails has a different thickness, the kit of surgical instruments according to embodiment 17 or 18. (20) A method for performing a single-piece posterior cut on the femur of a patient's knee, comprising: Positioning a single-piece posterior cutting block on the resected proximal tibial surface of the tibia of the patient's knee and adjacent to the resected condyle distal to the femur of the patient's knee with the knee in a flexed state, the cutting block comprising a base and a body, the body being rotatable relative to the base, the body defining a cutting guide therein; Aligning an alignment feature attached to the body with a marking on the femur and rotating the body relative to the base; Fixing the body to the femur; Using the cutting guide to perform a posterior femur cut using a cutting tool.

[0179] (21) The method according to embodiment 20, further comprising mounting the single-piece posterior cutting block on a tibial spacer, the tibial spacer being placed on the resected proximal tibial surface. (22) Mounting the cutting block on the tibial spacer comprises mounting the cutting block on the tibial spacer at a first position, and moving the cutting block along the tibial spacer from the first position towards the femur, the method according to embodiment 21. (23) The method according to any one of embodiments 20-22, further comprising selecting a single-piece posterior cutting block from a plurality of single-piece posterior cutting blocks, each of the plurality of single-piece posterior cutting blocks defining a respective cutting guide having a different position corresponding to a different anterior position of the posterior cut or a different cutting range. (24) Mounting a single-piece distal cutting block on a tibial spacer and performing a distal femoral cut using the single-piece distal cutting block, the method according to any one of embodiments 20-23. (25) The method further comprises selecting a single-piece distal cutting block from a plurality of single-piece distal cutting blocks, each of the plurality of single-piece distal cutting blocks defining a respective cutting guide having a different position corresponding to a different distal position of the distal cut, the method according to embodiment 24.

[0180] (26) Evaluating a flexed knee gap between a posterior portion of the native condyle of the femur and a proximal resected portion of the tibia with the knee in a flexed state, and evaluating an extended knee gap between a distal portion of the native condyle and the proximal resected portion of the tibia with the knee in an extended state, and performing a distal femoral cut at a distal position of the native condyle such that the obtained extended knee gap matches the flexed knee gap, the method according to any one of embodiments 20-25. ​​evaluating a flexion knee gap between a posterior portion of a natural condyle of the femur and a proximal resection portion of the tibia with the knee in a flexed state; evaluating an extension knee gap between a distal portion of the natural condyle and the proximal resection portion of the tibia with the knee in an extended state; performing the posterior femoral cut at a forward position of the natural condyle such that the obtained knee gap in flexion matches the extension knee gap, the method according to any one of Embodiments 20 to 25. further comprising flexing the knee before aligning the alignment feature, the method according to any one of Embodiments 20 to 27. further comprising marking a vertical line on the femur using a center line on a tibial spacer when the knee is in a flexed state and / or an extended state, the method according to any one of Embodiments 20 to 28. A method for providing an artificial knee joint to a patient, providing a plurality of cutting blocks of a certain type; positioning a selected cutting block of the certain type adjacent to the femur of the patient; including excising a portion of bone from the femur guided by the selected cutting block; the method including selecting the cutting block of the certain type from among the plurality of cutting blocks of the certain type before positioning; each of the plurality of cutting blocks of the certain type has a configuration variable, and the configuration variable has a value; the plurality of cutting blocks of the certain type includes two or more cutting blocks of the certain type having a difference in the value of the configuration variable with respect to each other; each of the two or more cutting blocks of the certain type having a difference in the value with respect to each other includes one or more graphical marks indicating at least a part of the value of the configuration variable of each respective cutting block.

[0181] (31) The method according to embodiment 30, wherein the graphical mark includes one or more directional mark elements. (32) The method according to embodiment 31, wherein the one or more directional mark elements indicate an increase, a decrease, or no change in the value or a part of the value. (33) When the cutting block is configured to cut bone from the femur so as to reduce the gap between a part of the femur and a part of the tibia in at least one orientation of the tibia with respect to the femur, the value or a part of the value represented by the graphical mark indicates a decrease in the value or a part of the value. The method according to any one of embodiments 30 to 32. (34) When the cutting block is configured to cut bone from the femur so as to keep the gap between a part of the femur and a part of the tibia unchanged in at least one orientation of the tibia with respect to the femur, the value or a part of the value represented by the graphical mark indicates no change in the value or a part of the value. The method according to any one of embodiments 30 to 33. (35) When the cutting block is configured to cut bone from the femur so as to increase the gap between a part of the femur and a part of the tibia in at least one orientation of the tibia with respect to the femur, the value or a part of the value represented by the graphical mark indicates an increase in the value or a part of the value. The method according to any one of embodiments 30 to 34.

[0182] (36) The cutting block has a front surface having an upper edge and a lower edge, and the directional mark element points toward the lower edge of the cutting block, so that the directional mark element indicates a decrease in the value or a part of the value. The method according to any one of embodiments 30 to 35. (37) The method according to any one of embodiments 30 to 36, wherein the absence of the directional mark element indicates no change in the value or a part of the value. (38) The method according to any one of embodiments 30 to 37, wherein the direction mark element points towards the upper edge of the cutting block, and the direction mark element indicates an increase in the value or a part of the value. (39) The method according to any one of embodiments 30 to 38, wherein one or more cutting blocks provided with a graphical mark are also provided with an alphabetical / numerical mark. (40) The method according to embodiment 39, wherein the alphabetical / numerical mark indicates at least a further part of the value as compared with the part of the value indicated by the graphical mark.

[0183] (41) The method according to embodiment 39 or 40, wherein the alphabetical / numerical mark indicates the magnitude of an increase or decrease in the value or a part of the value, or the constancy of the value or a part of the value. (42) The method according to any one of embodiments 39 to 41, wherein the alphabetical / numerical mark does not indicate an increase or decrease in the value or a part of the value. (43) The method according to any one of embodiments 39 to 42, wherein the graphical mark includes one or more further graphical mark elements, and the further graphical mark elements are elongated elements such as lines. (44) The method according to embodiment 43, wherein the direction mark element is provided at one end of the further graphical mark element or towards the one end, and / or the alphabetical / numerical mark is provided at one end of the further graphical mark element or towards the one end. (45) The method according to any one of embodiments 39 to 44, wherein the direction mark element includes the triangle having a vertex below the base of the triangle to indicate a decrease and / or the triangle having a vertex above the base of the triangle to indicate an increase.

[0184] (46) Each of the plurality of single-grain rear cutting blocks includes a graphical mark indicating different cutting heights of the single-grain rear cutting block. Selecting a first single-piece posterior cutting block that includes a first cutting guide and a first graphical mark indicating the cutting height of the first cutting guide; Mounting the first single-piece posterior cutting block on the tibial spacer and moving the first single-piece posterior cutting block into contact with the femur; The method according to any one of embodiments 20 to 23, further comprising: (47) The method according to embodiment 46, wherein the first graphical mark includes one or more directional mark elements. (48) Further comprising selecting a second single-piece posterior cutting block that includes a second cutting guide and a second graphical mark 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 graphical mark indicates that the cutting height of the second cutting guide is greater than the cutting height of the first cutting guide. The method according to embodiment 46 or 47. (49) Further comprising selecting a third single-piece posterior cutting block that includes a third cutting guide and a third graphical mark indicating the cutting height of the third cutting guide, wherein the cutting height of the third cutting guide is smaller than the cutting height of the first cutting guide, and the third graphical mark indicates that the cutting height of the third cutting guide is smaller than the cutting height of the first cutting guide. The method according to any one of embodiments 46 to 48. (50) The method according to any one of embodiments 46 to 49, wherein the cutting block has a front surface having an upper edge and a lower edge, and the directional mark element points toward the lower edge of the cutting block, so that the directional mark element indicates a decrease in the cutting height.

[0185] (51) The method according to any one of embodiments 46 to 50, wherein the absence of the directional mark element indicates, for example, that the cutting height is invariant with respect to a reference cutting height. (52) The method according to any one of embodiments 46 to 51, wherein the directional mark element points toward the upper edge of the cutting block, so that the directional mark element indicates an increase in the cutting height. (53) The method according to any one of embodiments 46 to 52, wherein one or more cutting blocks provided with a graphical mark are also provided with an alphabetical / numerical mark. (54) The method according to embodiment 53, wherein the alphabetical / numerical mark indicates at least a further characteristic of the cutting guide as compared with the characteristic indicated by the graphical mark. (55) The method according to embodiment 53 or 54, wherein the alphabetical / numerical mark indicates an increase or decrease in the cutting height, or the cutting height remaining unchanged.

[0186] (56) The method according to any one of embodiments 53 to 55, wherein the alphabetical / numerical mark does not indicate an increase or decrease in the cutting height. (57) The method according to any one of embodiments 46 to 56, wherein the graphical mark includes one or more further graphical mark elements, and the further graphical mark elements are elongated elements such as lines. (58) The method according to embodiment 57, wherein the direction mark element is provided at one end of the further graphical mark element or towards the one end, and / or the alphabetical / numerical mark is provided at one end of the further graphical mark element or towards the one end. (59) The method according to any one of embodiments 46 to 58, wherein the direction mark element includes the triangle having a vertex below the base of the triangle to indicate a decrease and / or the triangle having a vertex above the base of the triangle to indicate an increase.

Claims

1. A single-piece posterior cutting block, comprising: a base that can be mounted on the resected proximal tibia surface of a patient's knee during use; and a body pivotally attached to the base, the body including an alignment formation arranged to be aligned with markings on the femur during use, the body defining internally a cutting guide for receiving a cutting instrument for performing a single-piece posterior cut on the femur, and rotating the body relative to the base and tilting the cutting guide relative to the base by moving the alignment formation to align with the markings on the femur. A single-piece posterior cutting block comprising the body.

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

3. The cutting block according to claim 2, wherein the base includes a curved member and the body rides on the curved member when pivoting.

4. The cutting block according to claim 3, wherein the curved member has a non-constant radius of curvature and the pivot can translate relative to the base when the body rides on the curved member.

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

6. The cutting block according to claim 3 or 4, wherein the body includes a resilient biasing member arranged to maintain contact between the curved member and a portion of the body.

7. The cutting block according to any one of claims 3 to 6, wherein the body includes a fixture arranged to capture the curved member within a portion of the body.

8. The cutting block according to any one of claims 2 to 7, wherein the formation defines an elongated slot extending along a slot axis, the slot axis passing through the rotation axis, or the formation is a through-opening.

9. The cutting block according to any one of claims 1 to 8, wherein a rear surface of the cutting block defines a first plane, the cutting guide defines a second plane, and the first plane and the second plane form an acute angle of less than 80°.

10. The cutting block according to any one of claims 1 to 9, wherein the body defines a circular opening extending therethrough for receiving a bone pin.

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