Tibia trial insert system

Abstract

To provide an alternative tibia trial insert system.SOLUTION: A tibia trial insert system 1 comprises: a bearing component 100 having an upper joint surface 101, and a lower surface 102; a plate component 200 having an upper surface 201 and a lower surface 202; an interval adjustment assembly 300 configured so as to be arranged between the bearing component 100 and the plate component 200; multiple shims 500, 600, the respective shims 500, 600 configured to be slidable between a connection element and a base element, for adjusting a relative proximal / distal interval between the bearing component 100 and the plate component 200, and adjusting a proximal / distal height of the interval adjustment assembly 300.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tibial trial insert system. [Background technology]

[0002] During total knee arthroplasty, tibial trial insert systems are commonly used to assist a surgeon in determining the size, shape or other configuration of a permanent prosthesis for replacing a portion of the natural knee joint. In particular, such tibial trial insert systems are used to determine the relative spacing between the femoral and tibial components of the permanent prosthesis.

[0003] US2015 / 0359642A1 discloses a tibial trial insert system including a bearing component having an upper articular surface and an lower surface, a base component having an upper surface and a lower surface, the base component configured to removably engage the bearing component, and a plurality of shims, each shim configured to be slidable between the lower surface of the bearing component and the upper surface of the base component to change the relative proximal / distal spacing between the bearing component and the base component. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide an alternative tibial trial insert system. [Means for solving the problem]

[0005] According to the present invention, a tibial trial insert system includes a bearing component having an upper articular surface and an lower surface, a plate component having an upper surface and a lower fixation surface, a spacing adjustment assembly configured to be positionable between the bearing component and the plate component, the spacing adjustment assembly having at least one upper connection element configured to releasably engage with the bearing component, at least one lower base element configured to releasably engage with the plate component, a coupling structure for movably coupling the connection element and the base element in a proximal / distal direction and within a limited range, and a plurality of shims, each shim configured to be slidable between the connection element and the base element to adjust a proximal / distal height of the spacing adjustment assembly to adjust a relative proximal / distal spacing between the bearing component and the plate component. The present invention particularly avoids erroneous adjustment of the proximal / distal spacing between the bearing component and the plate component. To this end, the spacing adjustment assembly allows only limited relative proximal / distal movement between the bearing component and the plate component. To achieve said limited movement, the connection element and the base element are movably and captively connected by a connection structure. The limited movement prevents the insertion of an excessive number of shims and thus the setting of too large proximal / distal heights. As a result, the present invention helps to prevent errors during surgery and improve patient safety. Furthermore, due to the movable yet captive connection between the connection element and the base element, the spacing adjustment assembly can be easily handled during surgery, especially compared to simply placing loosely assembled and / or unassembled parts. Preferably, the spacing adjustment assembly is configured to be positionable between the lower surface of the bearing component and the upper surface of the plate component. Preferably, each shim is configured to be slidable between the lower surface of the connection element and the upper surface of the base element. Preferably, the connection element and the base element are relatively fixed in the anterior / posterior direction and / or the medial / lateral direction by the connection structure.The engagement of the connection element with the bearing component and the base element with the plate component constrains movement in the anterior / posterior and / or medial / lateral directions between the bearing component and the plate component. For engagement with the base element, the plate component preferably comprises a recess configured to receive at least a portion of the base element and constrain the base element in the anterior / posterior and / or medial / lateral directions relative to the plate component. For engagement with the connection element, the bearing component preferably comprises an engagement portion that interacts with a complementary engagement portion of the connection element, thereby forming a plug-in, latch and / or snap-in connection. Preferably, movement between the connection element and the base element in the proximal / distal direction is limited by an end stop or the like. In this specification, the terms "superior", "inferior", "anterior", "posterior", "medial", "lateral", "proximal" and "distal" are used according to their standard anatomical definitions. In this specification, the phrase "proximal / distal spacing" refers to a spacing extending in the proximal and / or distal directions. Similarly, the phrase "anterior / posterior" means anterior and / or posterior, and the phrase "medial / lateral" means medial and / or lateral. The plate component may also be referred to as a "tibial plateau component."

[0006] In one embodiment, the connecting structure forms a telescopic mechanism that is extendable in the proximal direction and retractable in the distal direction. Providing the connecting structure in the form of a telescopic mechanism allows a simple and robust design. The telescopic mechanism is telescoping in the proximal / distal direction, in that it is extendable in the proximal direction and retractable in the distal direction. The telescopic mechanism is fixed at one end to the base element and at the other end to the connection element. The telescopic mechanism is extendable in the proximal direction by sliding at least one shim of the plurality of shims between the connection element and the base element. Starting from the extended position, the telescopic mechanism is retractable in the distal direction by removing at least one shim of the plurality of shims between the connection element and the base element. Preferably, the telescopic mechanism comprises at least one cylinder element that is fixedly connected to the connection element and slidably received in a receiving bore of the base element. The telescopic mechanism is therefore single-stage. In other embodiments, two, three, four, five, six or more cylinder elements may be provided to form a corresponding number of stages of telescopic cylinders. Preferably, the proximal / distal movement of the cylinder elements in the receiving bore of the base element is limited by a proximal end stop and / or a distal end stop. Preferably, the cylinder elements and the receiving bore each have a non-circular, preferably elliptical or rectangular, cross section, thereby preventing relative rotation about the proximal / distal axis between the connecting element and the base element. The non-circular cross section inhibits relative rotation between the connecting element and the base element, and thus between the bearing component and the plate component. Preferably, the telescopic mechanism is extendable between 0 mm and 16 mm inclusive.

[0007] In one embodiment, the telescopic mechanism comprises a latching device configured to releasably latch the cylinder element to the base element in a fully retracted position. Releasably latching the cylinder element to the base element by the latching device in said fully retracted position provides improved stability and a more compact design during insertion of the tibial trial insert system into the patient's knee. The latch can be released by extending the telescopic mechanism proximally, i.e., by pushing or pulling the bearing component proximally, for example by sliding at least one of the shims between the connecting element and the base element.

[0008] In one embodiment, the latching device comprises at least one resilient latching member connected to the cylinder element for releasably latching the cylinder element to the base element and at least one latch portion formed on the base element and configured for latching interaction with the resilient latching member. Providing the latching device with at least one resilient latching member and at least one latch portion allows for a simple and robust design. The at least one resilient latching member and the at least one latch portion form said releasable latching connection in a fully retracted position of the cylinder element / telescopic mechanism.

[0009] In one embodiment, the cylinder element comprises at least one receiving bore, the resilient latching member comprises at least one head portion extending between a first end and a second end, and at least one compression spring member, the head portion and the compression spring member being received together in said receiving bore of the cylinder element, the first end of the head portion being configured to latch with the latch portion of the base element, and the compression spring member acting on the second end of the head portion to bias the head portion into a latched position in which the first end of the head portion protrudes from the receiving bore of the cylinder element and latches with the latch portion of the base element. The inventors have found that providing the resilient latching member with at least one head portion and at least one compression spring member results in a simple and robust design well suited for invasive applications. Preferably, the at least one receiving bore extends in a medial / lateral direction. Alternatively, the at least one receiving bore extends in an anterior / posterior direction. The head portion extends coaxially with the receiving bore and is biased by the at least one compression spring member. The bias acts toward the latched position. In one embodiment, a first end of the at least one compression spring member acts against a second end of the head portion, the second end of the compression spring member being supported on a portion of the cylinder element. In an alternative embodiment, the resilient latch member comprises two head portions, and the compression spring member is axially disposed between the two head portions for acting against a respective second end of the compression spring member.

[0010] In one embodiment, the resilient latch member comprises a first head portion and a second head portion opposite in an inward / outward direction, the base element comprises a first latch portion and a second latch portion opposite in an inward / outward direction, and a compression spring member is located between said first and second head portions and acts on their respective second ends to bias the first head portion to a latched position in which the first end of the first head portion protrudes from the receiving bore to latch with the first latch portion, and biases the second head portion to a latched position in which the first end of the second head portion protrudes from the receiving bore to latch with the second latch portion. Both the first and second head portions are received in the receiving bore of the cylinder element. The compression spring member is located between the first and second head portions and biases the first and second portions in opposite directions. By providing the resilient latch member with two opposing head portions and the base element with two opposing latch portions, an improved latch connection is possible. The improved latch connection has two connection "points", firstly, a connection point between the first head portion and the first latch portion, and secondly, a connection point between the second head portion and the second latch portion.

[0011] In one embodiment, the tibial trial insert system further comprises a handling instrument having an elongated shaft and a coupling mechanism disposed on said elongated shaft in a distal direction, the coupling mechanism configured to releasably couple to an anterior coupling of the spacing adjustment assembly. The handling instrument allows for simplified and ergonomic handling of the spacing adjustment assembly. The handling instrument can be used to place the spacing adjustment assembly between the bearing component and the plate component. The elongated shaft extends between a distal end and a proximal end. The coupling mechanism is disposed on the distal end of the elongated shaft. The coupling mechanism is configured to be manually operable. For this purpose, an operating element is preferably provided, configured to manually shift the coupling mechanism between a coupled state and a released state. The operating element is preferably a button, a switch, a slider, or the like. In a preferred embodiment, the anterior coupling of the spacing adjustment assembly is formed on the connection element. In an alternative embodiment, the anterior coupling is formed on the base element. In yet another embodiment, the anterior coupling is formed on the coupling structure.

[0012] In one embodiment, the front connection is formed on the connection element of the distance adjustment assembly, the connection element being made of a metallic material. By providing the front connection on the connection element and the connection element being made of a metallic material, the strength of the connection between the connection mechanism and the connection part can be improved. It is also possible to provide the front connection on the bearing component. However, the bearing component is preferably made of a plastic material, so that a possible connection between the connection mechanism and the connection part of the bearing component is less stable and robust compared to a connection between the connection mechanism and the connection part of the metallic connection element. Preferably, the front connection forms a protrusion protruding in the forward direction.

[0013] In one embodiment, the coupling mechanism is configured to releasably couple to the front coupling portion of each of the plurality of shims. Configuring the coupling mechanism to releasably couple to each of the plurality of shims also allows for simplified, ergonomic handling of the shims. Thus, handling tools can be used to position the spacing adjustment assembly between the bearing component and the plate component, and to slide the shims between the connecting element and the base element.

[0014] In one embodiment, the tibial trial insert system further comprises a securing ring component configured to be supported on and / or in the support of the bearing component and configured to be removably attached to the attachment part of the connecting element of the spacing adjustment assembly, thereby releasably retaining the removable engagement between the bearing component and the connecting element. By providing said securing ring component in the tibial trial insert system, the connection between the bearing component and the spacing adjustment assembly can be improved. For this purpose, the securing ring component can be supported on and / or in the support of the bearing component and can be attached to the attachment part of the connecting element. The removable attachment between the securing ring component and the attachment part can be in the form of, for example, a plug-in connection, a latch connection and / or a snap-in connection. The securing ring component retains the engagement between the bearing component and the connecting element at least in the proximal / distal direction.

[0015] In one embodiment, the attachment portion and / or the connection element are made of a metallic material. Making the attachment portion and / or the connection element from a metallic material increases the strength and durability of the releasable attachment of the securing component to the attachment portion / connection element. The attachment portion of the connection element can have any form, shape or size suitable for the purposes of the present invention.

[0016] In one embodiment, the support portion of the bearing component comprises a concave support surface recessed distally into the articular surface and a support opening extending between the support surface and the underside of the bearing component, the attachment portion of the connecting element comprises an attachment opening located directly below and in line with the support opening, and the securing component comprises a plug body configured to be plugged into the concave support surface and a hook member configured to pass through the support opening and securely engage with the attachment opening. The concave support surface is preferably flat and is configured to support the plug body of the securing component. The support opening extends between the support surface and the underside of the bearing component and is thus a through opening. The attachment opening is located directly below the support opening, is in line with the support opening and is configured to securely engage with the hook member. When the securing component is attached, the hook member passes through the support opening and securely engages with the attachment opening, thereby locking in the engagement between the bearing component and the connecting element. The plug body defines the shape and size of the securing component. The hook member serves as an attachment means for attaching the securing component to the connecting element. The plug body and hook member are fixedly connected. In one embodiment, the plug body and hook member form a single integral part. In another embodiment, the plug body and hook member are made from different materials and form separate parts of the securing component.

[0017] In one embodiment, the hook member is made of a metal material and / or the plug body is made of a plastic material. Making the hook member from a metal material improves the strength of the connection between the hook member and the attachment portion. Preferably, the plastic material of the plug body is the same as the plastic material of the bearing component, which allows the material properties, such as frictional properties, to be the same.

[0018] In one embodiment, the securing component comprises a locking device configured to releasably lock into a locking portion of the bearing component. By providing the securing component with said locking device, the connection between the securing component and the bearing component can be improved.

[0019] In one embodiment, the locking part of the bearing component comprises a locking slit extending in a transverse plane and the locking device of the securing component comprises a flat locking member configured to be rotatable in said transverse plane relative to the securing component between a locked position in which the flat locking member is positively engaged in the locking slit and a released position in which the flat locking member is not positively engaged in the locking slit. The locking slit of the bearing component extends in said transverse plane and therefore in the medial / lateral direction and in the anterior / posterior direction. The flat locking member is rotatably attached to the securing component, in particular rotatable relative to the plug body and / or the hook member. The flat locking member is rotatable between said locked position and said released position. Rotating the flat locking member to the released position releases the lock between the securing component and the bearing component and removes the securing component from the attachment of the connection element. [Brief description of the drawings]

[0020] Preferred exemplary embodiments of the present invention will now be described in detail with reference to the drawings, in which like elements are designated by like reference numerals throughout. The drawings generally show: [Figure 1] 1 illustrates a perspective view of one embodiment of a tibial trial insert system having a bearing component, a plate component, a spacing adjustment assembly, and a number of shims; [Diagram 2] FIG. 2 is a perspective view of a spacing adjustment assembly of the tibial trial insert system of FIG. 1 . [Diagram 3] FIG. 3 is a perspective exploded view of the spacing adjustment assembly of FIG. 2 . [Figure 4] 4 is a longitudinal cross-sectional view of the spacing adjustment assembly of FIGS. 2 and 3, viewed from the medial / lateral direction. FIG. [Diagram 5] 2 is a perspective view of a handling instrument configured to handle components of the tibial trial insert system according to FIG. 1; [Figure 6] 6 is a perspective view of a first handling situation in which the handling tool of FIG. 5 is used to handle a spacing adjustment assembly for engagement with a bearing component; [Figure 7] FIG. 13 is a perspective view showing a further handling situation in which a handling tool is used to engage the bearing component with the base component together with the spacing adjustment assembly. [Figure 8] FIG. 13 is a perspective view showing a further handling situation in which a handling tool is used to slide one of a number of shims between the bearing component and the plate component to increase the proximal / distal spacing between the components. [Figure 9] FIG. 13 is a top view showing various shims of the plurality of shims. [Figure 10] FIG. 13 is a top view showing various shims of the plurality of shims. [Figure 11] FIG. 13 is a top view showing various shims of the plurality of shims. [Figure 12] 2 is a further perspective view of the tibial trial insert system of FIG. 1 with the securing component removed from the bearing component and the spacing adjustment assembly; FIG. [Figure 13] FIG. 13 is a bottom view showing the bearing components and the securing components attached. [Figure 14] FIG. 2 is a detailed perspective view showing the securing component with the locking device of the securing component in the released position; [Figure 15] FIG. 13 is a further perspective view showing the securing component with the locking device in the locked position. [Figure 16]FIG. 16 is a bottom view of the securing component of FIGS. 14 and 15, with the locking device in the locked position; [Figure 17] FIG. 13 is a bottom view of the tibial trial insert system with the securing component attached and without the plate component. [Figure 18] FIG. 13 is a longitudinal cross-sectional view of the tibial trial insert system with the securing component attached and without the plate component. [Figure 19] 13 is a further longitudinal cross-sectional view of the tibial trial insert system with a modified securing component attached and without the plate component; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Referring to Fig. 1, there is provided a tibial trial insert system for use in a total knee arthroplasty. The tibial trial insert system 1 includes a bearing component 100, a plate component 200, a spacing adjustment assembly 300 (detailed in Figs. 2, 3, and 4), and a plurality of shims 500, 600, and 700 (detailed in Figs. 9, 10, and 11), of which only the shims 500 and 600 are shown in Fig. 1.

[0022] The bearing component 100 has an upper articular surface 101, an opposing lower surface 102, and a peripheral wall 103 extending from the lower surface 102 to the upper articular surface 101. The bearing component 100 further includes an anterior side 104, a posterior side 105, a lateral side 106, and a medial side 107. The upper articular surface 101 is configured to articulate with a natural or artificial condyle of the distal femur and includes a lateral articular surface portion 108 and a medial articular surface portion 109.

[0023] The plate component 200 has a superior surface 201, an opposing inferior fixation surface 202, and a peripheral wall 203 extending from the inferior fixation surface 202 to the superior surface 201. The plate component 200 further includes an anterior side 204, a posterior side (not numbered), a lateral side 206, and a medial side 207. The inferior fixation surface 202 is configured for direct or indirect fixation to the proximal end of the tibia. The plate component 200 may also be referred to as a tibial plateau component.

[0024] The spacing adjustment assembly 300 is configured to be positionable between the bearing component 100 and the plate component 200, in particular between the lower surface 102 of the bearing component 100 and the upper surface 201 of the plate component 200. The spacing adjustment assembly 300 includes an upper connection element 301, a lower base element 302, and a coupling structure C.

[0025] The upper connecting element 301 is configured to releasably engage with the bearing component 100. The lower base element 302 is configured to releasably engage with the plate component 200. The coupling structure movably couples the connecting element 301 and the base element 302 in a proximal / distal direction and to a limited extent. In other words, the connecting element 301 and the base element 302 are movably and capturably coupled to each other by the coupling structure C.

[0026] The spacing adjustment assembly 300 is intended to adjust the relative proximal / distal spacing between the bearing component 100 and the plate component 200. In other words, the spacing adjustment assembly 300 is intended to position the upper articular surface 101 and / or the bearing component 100 at different height levels relative to the plate component 200, particularly relative to the lower fixation surface 202. Such spacing or height adjustment is required for trial repositioning in total knee replacement surgery. The trial repositioning, as mentioned above, is a surgical step prior to the actual knee replacement surgery, in which the size, dimensions and / or shape of the tibial and femoral implant components required for the replacement of the knee joint are determined. The background related to this application of the tibial trial insert system 1 is well known to those skilled in the art.

[0027] With regard to the height adjustment and / or spacing adjustment, each shim 500 , 600 , 700 of the plurality of shims is configured to be slidable between the connecting element 301 and the base element 302 , in particular between the lower surface 307 of the connecting element 301 and the upper surface 308 of the base element 302 .

[0028] To that end, a single shim or multiple stacked shims can be inserted between the connecting element 301 and the base element 302. In other words, a single shim or more than a single shim can be used in combination among the multiple shims to provide additional spacing between the bearing component 100 and the plate component 200.

[0029] To adjust the proximal / distal spacing, the surgeon places the spacing adjustment assembly 300 between the bearing component 100 and the plate component 200 and engages the connecting element 301 with the bearing component and the base element 302 with the plate component in a manner described in more detail below. The actual spacing adjustment is accomplished by inserting at least one of the shims 500, 600, 700 between the connecting element 301 and the base element 302.

[0030] For releasably engaging with the connecting element 301, the bearing component 100 comprises an engaging portion 110 (see especially Figs. 13, 17). The engaging portion 110 is countersunk into the underside 102 of the bearing component 100 in the proximal direction. In the illustrated embodiment, the engaging portion 110 and the connecting element are configured to form a plug-in connection. The connecting element 301 and the engaging portion 110 can be plugged in the anterior / posterior direction. In the engaged state, relative movement between the connecting element 301 and the bearing component 100 is constrained at least in the proximal / distal and medial / lateral directions.

[0031] To improve the engagement between the connecting element 301 and the engagement portion 110, the connecting element 301 includes a spring portion 380. The spring portion 380 acts as a fastener / stop for the bearing component 100 and prevents the bearing component 100 from unintentionally disengaging from the connecting element 301. The spring portion 380 is configured to generate an auditory effect upon reaching full engagement with the engagement portion 110. This auditory effect indicates that the bearing component is properly engaged with the spacing adjustment assembly 300.

[0032] The base element 302 has a peripheral wall 324 extending between the lower surface 315 and the upper surface 308. Additionally, the base element 302 has an anterior side 325, a posterior side 326, an outer side 327, and an inner side 328. The peripheral wall 324 defines an outer surface shape (not numbered). To removably engage with the base element 302, the plate component 200 has a receiving recess 208 (see, in particular, Figs. 1, 7) that defines an inner surface shape (not numbered) that is at least partially complementary to the outer surface shape of the base element 302. In the engaged state, i.e. when the base element 302 is received in the receiving recess 208, the base element 302 is constrained in the anterior / posterior direction and the lateral / medial direction.

[0033] The coupling structure C forms a proximally extendable and distally retractable telescopic mechanism configured to movably and captively couple the connecting element 301 to the base element 302.

[0034] The telescopic mechanism comprises a cylinder element 303 fixedly connected to the connecting element 301 and slidably received in a receiving bore 310 of the base element 302. The cylinder element 303 and the receiving bore 310 form a single-stage telescopic cylinder of the telescopic mechanism.

[0035] The cylinder element 303 and the receiving bore 310 extend coaxially in the proximal / distal direction.

[0036] The cylinder element 303 has a distal radial collar 313. The bore 310 of the base element 302 has a proximal radial collar 314. The distal radial collar 313 of the cylinder element 303 and the proximal radial collar 314 of the base element 302 form an end stop to limit proximal movement of the cylinder element 303 within the bore 310.

[0037] The cylinder element 303 and the bore 310 each have a non-circular cross-section. In the illustrated embodiment, the cross-section of the cylinder element and the cross-section of the receiving bore 310 are each rectangular. The non-circular cross-sections prevent relative rotation between the cylinder element 303 and the bore 310, and thus between the connecting element 301 and the base element 302.

[0038] The cylinder element 303 is fixedly connected to the connecting element 301. The connecting element 301 comprises a pin hole 322. The cylinder element 303 comprises a pin portion 321. The pin portion 321 protrudes proximally from the proximal end of the cylinder element 303 and is fixedly inserted into the pin hole 322. The pin portion 321 and the pin hole 322 can form a press fit and / or can be bonded by an adhesive connection.

[0039] The telescopic mechanism C comprises a latching device L configured to releasably latch the cylinder element 303 in a fully retracted position relative to the base element 302. Releasably latching the telescopic mechanism C in the fully retracted position, i.e., the position of minimum proximal / distal height, ensures that the spacing adjustment assembly 300 is stable and compact for easy and safe insertion between the bearing component 100 and the plate component 200 during surgery.

[0040] In the illustrated embodiment, the latch device L comprises at least one resilient latch member 390 connected to the cylinder element 303 and at least one latch portion 394 formed on the base element 302. The resilient latch member 390 and the latch portion 394 are configured to releasably lock the cylinder element 303 to the base element 302 via a latching interaction.

[0041] The latched connection between the resilient latch member 390 and the latch portion 394 is releasable by pulling the connecting element 301 in a proximal direction.

[0042] In the illustrated embodiment, the cylinder element 303 includes at least one receiving bore 396 and the resilient latch member 390 includes at least one head portion 391 and at least one compression spring member 392. Both the head portion 391 and the compression spring member 392 are received in said receiving bore 396. In the illustrated embodiment, the receiving bore 396 extends in an inward / outward direction.

[0043] The head portion 391 extends between a first end 3911 and a second end 3912, the first end 3911 configured to latch with the latch portion 394, and the compression spring member 392 acts against the second end 3912. The compression spring member 392 is configured to bias the head portion 391 into a latched position in which the first end 3911 protrudes from the receiving bore 396 and latches with the latch portion 394.

[0044] In the illustrated embodiment, the resilient latch member 390 comprises said (first) head portion 391 and a second head portion 393 opposite in the inward / outward direction. Furthermore, the base element 302 comprises said (first) latch portion 394 and a second latch portion 395 opposite in the inward / outward direction. The compression spring member 392 is located between the first head portion 391 and the second head portion 393 and acts on the respective second ends 3912, 3932. The second head portion 393 is received in a receiving bore 396. The compression spring member 396 biases the first head portion 391 to the above-mentioned latched position in which the first end 3911 of the first head portion 391 protrudes from the receiving bore and latches with the first latch portion 394. The compression spring member 392 also biases the second head portion 393 into a latched position in which a first end 3931 of the second head portion 393 projects from the receiving bore 396 to latch with the second latch portion 395 .

[0045] In the illustrated embodiment, the tibial trial insert system 1 further comprises a handling instrument 800, as shown in Figures 5 to 8. The handling instrument 800 comprises an elongate shaft 820 and a coupling mechanism 840.

[0046] The elongate shaft 820 extends between a proximal end 821 and a distal end 822 .

[0047] The coupling mechanism 840 is disposed at the distal end 822 and is configured to releasably couple to the front coupling portion 370 (see FIGS. 3 and 4) of the spacing adjustment assembly 300.

[0048] When releasably coupled to the anterior link 370, the handling tool 800 allows for simplified, ergonomic engagement of the spacing adjustment assembly 300 with the bearing component 100 (see FIG. 6). After engaging the spacing adjustment assembly 300 with the bearing component 100, the handling tool, with the coupling mechanism 840 still coupled to the anterior link 370, can be used to insert the assemblies 100, 300 into the patient's knee and engage the base element 302 of the spacing adjustment assembly 300 with the plate component 200 (see FIG. 7).

[0049] In the illustrated embodiment, the coupling mechanism 840 comprises a housing 845 , a coupling finger 841 , a coupling protrusion 846 , a spring element 842 that is disposed inside the housing 845 and therefore is not visible in the drawings, and a release button 847 .

[0050] Release button 847 is biased by spring element 842 and is configured to be manually operable, i.e., a thumb can be used to press release button 847 against the bias of spring element 842. A distal end of release button 847 forms coupling finger 841. Coupling finger 841 is movable in a proximal / distal direction by movement of release button 847.

[0051] Coupling projection 846 projects distally from the distal end of housing 845 .

[0052] In the illustrated embodiment, the front coupling 370 of the spacing adjustment assembly 300 is formed on the connecting element 301. The connecting element 301 is made of a metallic material. Thus, the connection between the connecting mechanism 840 and the front coupling has improved strength and stability compared to connecting the connecting mechanism to a coupling made of a plastic material, such as a plastic coupling formed on a bearing component.

[0053] In the illustrated embodiment, the front coupling portion 370 includes a coupling protrusion 371 and a coupling opening 372. The coupling protrusion 371 is configured to securely engage the coupling protrusion 846 of the coupling mechanism 840. The coupling opening 372 is configured to securely engage the coupling finger 841 of the coupling mechanism 840.

[0054] In the illustrated embodiment, the coupling mechanism 840 is also configured to releasably couple to the anterior connections AP, AP' of each of the plurality of shims 500, 600, 700 (see Figures 9, 10 and 11).

[0055] The shims 500, 600, and 700 depicted in FIGS. 9, 10, and 11 can be represented as a first shim 500, a second shim 600, and a third shim 700.

[0056] The front connecting portion AP′ of the third shim 700 is essentially the same as the front connecting portion 370 of the connecting element 301 , and has a connecting protrusion 701 and a connecting opening 702 .

[0057] The coupling protrusion AP of the first shim 500 and the second shim 600 each have a coupling recess 501, 601 and a coupling opening 502, 602. The coupling recesses 501, 601 and the coupling openings 502, 602 are identical in form and function. The coupling recesses 501, 601 are configured to receive the coupling protrusion 846 of the coupling mechanism 840. The coupling openings 502, 602 are configured to receive the coupling fingers 841.

[0058] In the illustrated embodiment, each shim of the plurality of shims 500, 600, 700 comprises two spring elements S, each of which comprises a latch protrusion P, i.e., a latching interaction with a complementary latch portion 351 of the base element 302 (see FIG. 3).

[0059] In the illustrated embodiment, the complementary latching portions 351 are arranged on or in an outer wall of a boss portion 350 of the base element. Said boss portion 350 defines the receiving bore 310. In the drawings, only one complementary latching portion 351 is visible. However, the boss portion 350 comprises two complementary latching portions 351 that are on opposite sides in the inner / outer direction. A spring element S with a connecting protrusion P prevents unintentional removal of the respective shim 500, 600, 700.

[0060] In the illustrated embodiment, the tibial trial insert system 1 further comprises a securing component 900 (see FIGS. 12 to 19 ). The securing component 900 is configured to secure a releasable engagement between the bearing component 100 and the connecting element 301 of the spacing adjustment assembly 300. To this end, the securing component 900 is configured to be supported on and / or in the support 111 of the bearing component 100 and configured to be releasably attached to the mounting portion 360 of the connecting element 301.

[0061] In the illustrated embodiment, the bearing portion 111 of the bearing component 100 comprises a concave bearing surface 1111 and a support opening 1112. The concave bearing surface 1111 is recessed distally into the articular surface 101. The support opening 1112 is located on the concave bearing surface 1111 and extends between the bearing surface 1111 and the underside 102 of the bearing component 100. The concave bearing surface 1111 is located between the medial articular surface portion 109 and the lateral articular surface portion 108.

[0062] The mounting portion 360 of the connecting element 301 includes a mounting opening 3601. When the spacing adjustment assembly 300 is engaged with the bearing component 100, the mounting opening 3601 is distally disposed below and aligned with the support opening 1112.

[0063] In the illustrated embodiment, the securing component 900 comprises a plug body 901 and a hook member 902 .

[0064] The plug body 901 is configured to be inserted into the concave support surface 1111. In the illustrated embodiment, the outer shape of the plug body 901 (not numbered) is complementary to the inner shape of the concave support surface 1111 (not numbered).

[0065] The hook members 902 are configured to pass through the support openings 1112 and securely engage the attachment openings 3601 (see particularly Figures 13 and 18).

[0066] In the illustrated embodiment, the securing component 900 further comprises a locking device 903 for releasably locking to the locking portion 112 of the bearing component 100. Releasably locking the securing component 900 to the bearing component 100 allows the securing component to be easily attached and detached to the remaining components of the tibial trial insert system 1.

[0067] In the illustrated embodiment, the locking portion 112 of the bearing component 100 includes a locking slit 1121 and the locking device 903 includes a flat locking member 9031 .

[0068] The locking slit 1121 extends in a transverse plane, ie in the medial / lateral and anterior / posterior directions, and is located at the anterior end of the concave support surface 1111 .

[0069] The flat locking member 9031 is configured to be rotatable relative to the plug body 901 and the hook member 902 between a locked position and a released position. When the plug body 901 is supported by the concave support surface 111, the flat locking member is rotatable in the transverse plane of the locking slit 1121 between a locked position (see Figures 13, 15, 16, and 18) and a released position (see Figure 14). In the locked position, the flat locking member 9031 is securely engaged with the locking slit 1121. In the released position, the flat locking member 9031 is not securely engaged with the locking slit 1121.

[0070] In the illustrated embodiment, the flat locking member 9031 has a non-circular outer shape with two spring portions 9033. The spring portions 9033 interact with an inner shape of a receiving recess (not numbered) of the plug body 901 in which the flat locking member 9031 is received. The flat locking member 9031 is operatively connected to a threaded member 9032. Rotation of the threaded member 9032 rotates the flat locking member 9031 between a locked position and an released position.

[0071] 19 illustrates the use of an alternative securing ring component 900a, which may be considered a variation of the securing ring component 900. The securing ring component 900a has a differently shaped plug body 901a. In particular, the plug body 901a forms a stem that is configured to interact with the intercondylar notch of the femoral component. The securing ring component 901a and the securing ring component 900 are interchangeable. By selecting either the securing ring component 900 or the alternative securing ring component 900a, the surgeon can change from one type of surgery to another.

[0072] With reference to securing component 900, plug body 901 and hook member 902 form a single, integral piece design. In contrast, plug body 901a and hook member 902a of securing component 900a are formed as separate pieces. Plug body 901a is made of a plastic material. Hook member 902a is made of a metal material M. Hook member 902a is connected to plug body 901a by a pin member 904a. Locking device 903a of securing component 900a is identical to locking device 903 of securing component 900.

Claims

1. A tibial trial insert system (1), comprising: a bearing component (100) having an upper articular surface (101) and an lower surface (102); A plate component (200) having an upper surface (201) and a lower surface (202); a spacing adjustment assembly (300) configured to be positionable between the bearing component (100) and the plate component (200), the spacing adjustment assembly (300) having at least one upper connection element (301) configured to be releasably engaged with the bearing component (100), at least one lower base element (302) configured to be releasably engaged with the plate component (200), and a coupling structure (C) that movably couples the connection element (301) and the base element (302) in a proximal / distal direction and within a limited range; a plurality of shims (500, 600, 700), each shim (500, 600, 700) configured to be slidable between the connecting element (301) and the base element (302) to adjust a proximal / distal height of the spacing adjustment assembly (300) to adjust a relative proximal / distal spacing between the bearing component (100) and the plate component (200); Tibial trial insert system.

2. The tibial trial insert system (1) according to claim 1, wherein the connecting structure (C) forms a telescopic mechanism extendable in the proximal direction and retractable in the distal direction, and comprises at least one cylinder element (303) fixedly connected to the connecting element (301) and slidably received in a receiving bore (310) of the base element (302).

3. 3. The tibial trial insert system (1) according to claim 2, wherein the telescopic mechanism comprises a latch device (L) configured to releasably latch the cylinder element (303) in a fully retracted position relative to the base element (302).

4. 4. The tibial trial insert system (1) according to claim 3, wherein the latch device (L) comprises at least one resilient latch member (390) connected to the cylinder element (303) to releasably latch the cylinder element (303) to the base element (302), and at least one latch portion (394) formed on the base element (302) and configured for latching interaction with the resilient latch member (390).

5. The cylinder element (303) includes at least one receiving bore (396), the resilient latch member (390) includes at least one head portion (391) extending between a first end (3911) and a second end (3912), and at least one compression spring member (392), the head portion (391) and the compression spring member (392) being both received in the receiving bore (396), and the first end (3911) of the head portion (391) being in contact with the base element (392).

5. The tibial trial insert system (1) of claim 4, wherein the compression spring member (392) is configured to latch with the latch portion (394), and the compression spring member (392) acts on the second end (3912) of the head portion (391) to bias the head portion (391) to a latched position in which the first end (3911) of the head portion (391) protrudes from the receiving bore (396) of the cylinder element (303) and latches with the latch portion (394) of the base element (302).

6. The resilient latch member (390) comprises a first head portion (391) and a second head portion (393) on opposite sides in an inward / outward direction, the base element (302) comprises a first latch portion (394) and a second latch portion (395) on opposite sides in an inward / outward direction, and the compression spring member (392) is located between the first head portion (391) and the second head portion (393) and acts on their respective second ends (3912, 3932), thereby 6. The tibial trial insert system (1) of claim 5, wherein a first end (3911) of the first head portion (391) protrudes from the receiving bore (396) to bias the first head portion (391) to a latching position in which it latches with the first latch portion (394), and a first end (3931) of the second head portion (393) protrudes from the receiving bore (396) to bias the second head portion (393) to a latching position in which it latches with the second latch portion (395).

7. 7. The tibial trial insert system (1) of any one of claims 1 to 6, further comprising a handling instrument (800) having an elongated shaft (820) and a coupling mechanism (840) disposed on the elongated shaft (820) in a distal direction, the coupling mechanism (840) configured to releasably couple to an anterior coupling portion (370) of the spacing adjustment assembly (300).

8. The tibial trial insert system (1) according to claim 7, wherein the anterior connection portion (370) is formed on the connection element (301) of the spacing adjustment assembly (300), and the connection element (301) is made of a metallic material.

9. The tibial trial insert system (1) according to claim 7, wherein the connection mechanism (840) is configured to be releasably connected to an anterior connection portion (AP, AP') of each of the plurality of shims (500, 600, 700).

10. 2. The tibial trial insert system (1) of claim 1, further comprising a securing component (900, 900a), the securing component (900, 900a) configured to be supported on and / or in a support portion (111) of the bearing component (100) and configured to be removably attached to a mounting portion (360) of the connecting element (301) of the spacing adjustment assembly (300), thereby releasably retaining a removable engagement between the bearing component (100) and the connecting element (301).

11. The tibial trial insert system (1) according to claim 10, wherein the mounting portion (360) and / or the connecting element (301) are made of a metallic material.

12. 11. The tibial trial insert system (1) according to claim 10, wherein the support portion (111) of the bearing component (100) comprises a concave support surface (1111) recessed distally into the articular surface (101) and a support opening (1112) extending between the support surface (1111) and an underside (102) of the bearing component (100), the attachment portion (360) of the connecting element (301) comprises an attachment opening (3601) disposed distally directly below and in alignment with the support opening (1112), and the securing component (900, 900a) comprises a plug body (901, 901a) configured to be inserted into the concave support surface (1111) and a hook member (902, 902a) configured to pass through the support opening (1112) and securely engage the attachment opening (3061).

13. The tibial trial insert system (1) according to claim 12, wherein the hook member (902a) is made of a metallic material and / or the plug body (901, 901a) is made of a plastic material.

14. The tibial trial insert system (1) according to claim 10, wherein the securing component (900, 900a) comprises a locking device (903, 903a) configured to releasably lock into a locking portion (112) of the bearing component (100).

15. The tibial trial insert system (1) according to claim 14, wherein the locking portion (112) of the bearing component (100) comprises a locking slit (1121) extending in a transverse plane, and the locking device (903, 903a) of the securing component (900, 900a) comprises a flat locking member (9031) configured to be rotatable in the transverse plane relative to the securing component (900, 900a) between a locked position in which the flat locking member (9031) is securely engaged in the locking slit (1121) and a released position in which the flat locking member (9031) is not securely engaged in the locking slit (1121).

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