Augment for bone implant and set of augments
The augment for bone implants addresses the issue of inadequate cement fixation by incorporating an undercut in its design, which enhances the stability and longevity of the implant by improving the bond between the implant and the bone.
Patent Information
- Application Number
- JP2024187719
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-27
- Filing Date
- 2024-10-24
- Publication Date
- 2025-05-13
AI Technical Summary
Conventional augments for bone implants lack effective cement fixation, which can lead to instability and potential failure of the implant.
The augment features a body with an undercut at the interface for securing the fixation element, which enhances cement fixation by allowing bone cement to fill the undercut, thereby improving the stability of the bone implant.
The use of an undercut in the augment significantly improves cement fixation, leading to enhanced stability and longevity of the bone implant by ensuring a stronger bond between the implant and the bone.
Smart Images
Figure 2025074050000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to an augment and a set of augments for a bone implant. Summary of the Invention
[0002] The augment according to independent claim 1 provides improved cementation over conventional augmentations.
[0003] An augment for a bone implant, particularly for the tibia or femur, has a body, the body having an interface for fixing the augment to a plateau of the bone implant, an interface for fixing the augment to a bone, and an interface for a fixation element for anchoring the bone implant in the medullary cavity of a bone, particularly the tibia or femur, extending between the interface for fixing the augment to the plateau and the interface for fixing the augment to a bone, the body having an undercut at the interface for the fixation element, where bone cement in the undercut improves cement fixation.
[0004] The undercut may be defined to include a conical or concave shaped portion of the body from the interface for securing the augment to the bone to the interface for securing the augment to the plateau, which facilitates manufacturing of the augment.
[0005] It may be defined that the body extends at a first height between the interface for fixing the augment to the plateau and the interface for fixing the augment to the bone, and the undercut extends at a second height lower than the first height between the interface for fixing the augment to the plateau and the interface for fixing the augment to the bone, in particular from the second height to the interface for fixing the augment to the plateau.
[0006] In one embodiment, the interface for anchoring the augment to the bone extends substantially in a plane, and the undercut comprises, at least in part, a wall of the body disposed at an angle of 89 to 45 degrees, particularly 89 to 79 degrees, to the plane.
[0007] It may be provided that the body tapers from the interface for securing the augment to the plateau to the interface for securing the augment to the bone at a portion other than the interface with the fixation element, or that the interface for securing the augment to the bone extends substantially in a plane and the body extends from the interface for securing the augment to the plateau to the interface for securing the augment to the bone at a 90 degree or substantially 90 degree angle to the plane at a portion other than the interface with the fixation element, i.e., no undercuts are located on the surface of the body that is not used for cement fixation.
[0008] The body may define a taper from an interface for anchoring the augment to the plateau to an interface for anchoring the augment to the bone.
[0009] The body can include a surface extending between an interface for securing the augment to the plateau and an interface for securing the augment to bone, the surface including an interface for the fixation element. The undercut is, for example, integrated into the surface.
[0010] The surface may at least partially have a roughened surface, for example at the interface with the fixation element, whereby improved cement fixation may be achieved.
[0011] The surface may, for example, have a smooth surface other than the interface with the fixation element, i.e., no roughness is provided in the areas not used for cement fixation.
[0012] In one embodiment, the interface to the fixation element includes a portion of the circumference of the body extending between the interface for fixing the augment to the plateau and the interface for fixing the augment to the bone, and the undercut extends along the portion of the circumference, in particular over the entire portion of the circumference, thereby providing improved cement fixation.
[0013] An augment set can be provided that includes at least two augments, the bodies of the at least two augments extending at different heights between an interface for fixing the respective augment to the plateau and an interface for fixing the augment to bone, or the interfaces to the fixation elements are formed for fixation elements of different sizes, or the undercuts are each different in shape or angle.
[0014] It may be defined that the set of augments includes a first augment and a second augment, the first augment and the second augment are positionable adjacent to one another, and an interface for fixing the first augment to a plateau of the bone implant and an interface for fixing the second augment to the bone are formed to join the first augment and the second augment.
[0015] In the set of augments, a second augment may be defined as being formed without an undercut at its interface to the fixation element, i.e., the second augment may be a conventional augment.
[0016] Further advantageous embodiments will become apparent from the following description and the drawings. [Brief description of the drawings]
[0017] [Figure 1a] FIG. 1 is a schematic perspective view of an augment for a tibial bone implant. [Figure 1b] FIG. 13 is a top view of a tibial bone implant augmentation. [Figure 1c] FIG. 13 is a cross-sectional view of a tibial bone implant augment. [Diagram 2] FIG. 2 is a schematic perspective view of an augment and at least a portion of a tibial bone implant. [Figure 3a] FIG. 13 is a top view of a femoral bone implant augmentation. [Figure 3b] FIG. 1 is a cross-sectional view of a femoral bone implant augment. [Figure 4] FIG. 1 is a schematic perspective view of an augment for a femoral bone implant. [Diagram 5] FIG. 2 is a schematic perspective view of an augment and at least a portion of a femoral bone implant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] FIG. 1a is a schematic perspective view of an augment 102 for a tibial bone implant.
[0019] The augment 102 has a body 104. The body 104 has a first interface 106. The first interface 106 is configured for securing the augment 102 to a plateau of a bone implant. The body 104 has a second interface 108. The second interface 108 is configured for securing the augment 102 to a bone. The body 104 has a third interface 110 for an anchoring element to anchor the bone implant within the medullary canal of the bone.
[0020] The third interface 110 extends between the first interface 106 and the second interface 108 .
[0021] The body 104 includes a surface extending between a first interface 106 and a second interface 108. The surface includes a third interface 110.
[0022] The surface has a rough surface at least partially at the third interface 110. The surface at the third interface 110 has an average roughness of more than 1.5 μm, in particular in the range of 3.5 μm to 9 μm, thereby ensuring that the bone cement stays on the rough surface at the third interface 110. For example, a smaller average roughness, for example an average roughness Ra≦1.5 μm, results in a smooth surface.
[0023] The face may be defined as having a smooth surface except at the third interface 110. The body 104 has an undercut at the third interface 110.
[0024] The third interface 110 includes a portion of the circumference of the body 104 that extends between the first interface 106 and the second interface 108. In an embodiment, the undercut extends along a portion of the circumference, and more particularly, the entire circumference portion.
[0025] 1b is a top view of the tibial bone implant augment 102. The third interface 110 has a first curved portion 112 having a shape corresponding to the sidewall shape of the fixation element of the tibial bone implant in the region of the third interface 110. The third interface 110 has within the first curved portion 112 a second curved portion 114 having a shape corresponding to the sidewall shape of the wing of the tibial bone implant in the region of the third interface 110.
[0026] FIG. 1c is a cross-sectional view of the tibial bone implant augment 102 taken along the line AA in FIG. 1b.
[0027] In an embodiment, the second interface 108 extends substantially in a plane. In an embodiment, the undercut comprises, at least in part, a wall of the body 104 disposed at an angle of 89 to 45 degrees, in particular 89 to 79 degrees, relative to the plane.
[0028] In one embodiment, the undercut comprises a conical or concave shaped portion of the body 104 from the second interface 108 to the first interface 106 .
[0029] The body 104 extends between the first interface 106 and the second interface 108 at a first height 114. In an embodiment, the undercut extends between the first interface 106 and the second interface 108 at a second height 116. The second height 116 is less than the first height 114. In an embodiment, the second height 116 is a portion of the first height 114, in particular at least one sixth, or at least one fifth, or at least one quarter.
[0030] In an embodiment, the undercut extends from the second height 116 to the first interface 106 .
[0031] In an embodiment, the body 104 tapers from the first interface 106 to the second interface 108, except at the third interface 110. In an embodiment, the body 104 tapers from the first interface 106 to the second interface 108. The body 104 may be defined to extend at a 90 degree angle relative to the plane from the first interface 106 to the second interface 108, except at the third interface 110. The body 104 may be defined to taper only except at the third interface 110.
[0032] FIG. 2 is a schematic perspective view of the augment 102 and at least a portion of a tibial bone implant.
[0033] The bone implant comprises a plateau 202 which can be placed on a horizontally osteotomized and prepared tibia for this purpose. The bone implant has a fixation element 206 which is formed for anchoring the bone implant in the medullary cavity of the prepared tibia for this purpose.
[0034] The third interface 110 is formed to receive a part of the fixing element 206. The fixing element 206 comprises a coupling element with a central axis. In an embodiment, the coupling element is an opening into which a shaft, not shown in detail in the drawings, in particular a screwable shaft, is inserted. In this case, the opening is a threaded hole. The central axis of this threaded hole, i.e. of the coupling element, is for example perpendicular or substantially perpendicular to the plateau 202. In an embodiment, the third interface 110 and the part of the fixing element 206 have surface shapes and sizes that correspond to each other. Between the third interface 110 and the fixing element 206, for example, a slit-shaped cement pocket extends, the slit bottom of which forms the plateau 202. The cement pocket opens in the direction of the bone, i.e. in this case the tibia. Thereby, the bone cement can enter the cement pocket through the opening formed therein and bite into it after hardening. The undercut of the third interface 110 is intended for this biting, the surface of the third interface 110 gradually moves radially away from the extension axis of the threaded hole towards the plateau 202. It may therefore be defined that the surface of the third interface 110, over its height 116, gradually moves away from the axis of extension of the coupling element towards the plateau 202.
[0035] 3a is a top view of the femoral bone implant augment 102. The third interface 110 of the femoral bone implant differs from the third interface 110 of the tibial bone implant in that it does not have the curvature described for the tibial bone implant.
[0036] FIG. 3b is a cross-sectional view of the femoral bone implant augment 102 taken along the line AA in FIG. 3a.
[0037] 4 is a schematic perspective view of the femoral bone implant augment 102. In an embodiment, the third interface 110 is configured to be positioned next to the fixation element on a plateau of the femoral bone implant.
[0038] FIG. 5 is a schematic perspective view of the augment 102 and at least a portion of a femoral bone implant.
[0039] The plateau 202 can be positioned on a femur that has been horizontally osteotomized and prepared for this purpose. A portion of the plateau 202 is configured for anchoring a bone implant in the medullary canal of the femur that has been prepared for this purpose. The third interface 110 is positioned adjacent to a portion of the plateau 202.
[0040] The tibia and femur are examples of bones to which the augment 102 can be applied.
[0041] The augment 102 is configured to bridge the distance between the plateau 202 and the bone, such as the distance between a first horizontal osteotomy and a second horizontal osteotomy distal thereto.
[0042] In an embodiment, the plateau 202 and the augment 102 are bonded to one another at a first interface 106. In an embodiment, the plateau 202 is bonded in part directly to the bone. In an embodiment, the augment 102 is bonded to the bone at a second interface 108.
[0043] In an embodiment, the plateau 202 and the augment 102 are configured to be bonded to bone using bone cement. In an embodiment, the second interface 108 and / or the third interface 110 have a roughened surface for contacting bone cement. The second interface 108 and / or the third interface 110 preferably have a roughened surface within a cement pocket, particularly a slit-shaped cement pocket, formed in the surface of the augment 102.
[0044] In an embodiment, bone cement is placed in the undercut. The bone cement in the undercut provides better fixation of the bone implant with the augment 102. The augment 102 is easily accessible during resection. Cementation with bone cement in the undercut can be easily removed during resection.
[0045] The practitioner may be provided with a set of augments 102.
[0046] The set of augments 102 may include, for example, at least two of the described augments 102, where the bodies 104 of the at least two augments 102 extend between a first interface 106 and a second interface 108 at different heights.
[0047] The set of augments 102 includes, for example, at least two of the described augments 102, where the third interface 110 is configured to receive fixation elements 206 of different sizes.
[0048] A set of augments 102 may include, for example, at least two of the described augments 102, each with a different undercut shape or angle.
[0049] In one embodiment, the set includes a first augment 102 and a second augment 102 formed as described for the bone implant. The first augment 102 and the second augment 102 are formed to be positionable adjacent to each other. A first interface 106 for fixing the first augment 102 to the plateau 202 of the bone implant and a second interface 108 for fixing the second augment 102 to the bone are formed to join the first augment 102 and the second augment 102. Thus, the augments 102 are stackable. This allows for various gap bridging.
[0050] It may be defined that the second augment 102 is formed without an undercut at the third interface 110 to the fixation element 206. The cement fixation is provided, for example, to the augment 102 of the stack that is positioned closest to the bone.
Claims
1. An augment (102) for a bone implant, in particular for the tibia or femur, comprising The augment (102) has a body (104); The body (104) an interface (106) for fixing the augment (102) to the plateau (202) of the bone implant; an interface (108) for fixing the augment (102) to bone; and an interface (110) for a fixation element (206) for anchoring the bone implant in the medullary canal of a bone, in particular the tibia or femur, extending between the interface (106) for fixing the augment (102) to the plateau (202) and the interface (108) for fixing the augment (102) to a bone; The augment (102), wherein the body (104) has an undercut at the interface (110) with the fixation element (206).
2. 2. The augment (102) of claim 1, wherein the undercut comprises a conical or concave shaped portion of the body (104) from the interface (108) for securing the augment (102) to bone to the interface (106) for securing the augment (102) to the plateau (202).
3. the body (104) extends at a first height between the interface (106) for securing the augment (102) to the plateau (202) and the interface (108) for securing the augment (102) to bone; 3. The augment (102) according to claim 1 or 2, characterized in that the undercut extends at a second height (116) lower than the first height (114) between the interface (106) for fixing the augment (102) to the plateau (202) and the interface (108) for fixing the augment (102) to the bone, in particular from the second height (116) to the interface (106) for fixing the augment (102) to the plateau (202).
4. the interface (108) for fixing the augment (102) to bone extends in a substantially plane; The augment (102) according to any one of claims 1 to 3, characterized in that the undercut comprises, at least in part, a wall of the body (104) arranged at an angle of 89 to 45 degrees, in particular 89 to 79 degrees, relative to the plane.
5. 5. The augment (102) of claim 1, wherein the body (104) tapers from the interface (106) for fixing the augment (102) to the plateau (202) to the interface (108) for fixing the augment (102) to the bone at a portion other than the interface (110) with the fixation element (206) or the interface (108) for fixing the augment (102) to the bone extends substantially in the plane, and the body (104) extends from the interface (106) for fixing the augment (102) to the plateau (202) to the interface (108) for fixing the augment (102) to the bone at an angle of 90 degrees or substantially 90 degrees with respect to the plane at a portion other than the interface (110) with the fixation element (206).
6. The augment (102) of any one of claims 1 to 5, characterized in that the body (104) is tapered from the interface for fixing the augment (102) to the plateau (202) to the interface for fixing the augment (102) to bone.
7. the body (104) includes a surface extending between the interface (106) for securing the augment (102) to the plateau (202) and the interface (108) for securing the augment (102) to bone; The augment (102) according to any one of the preceding claims, characterized in that said surface comprises said interface (110) with said anchoring element (206).
8. The augment (102) of claim 7, wherein the surface has at least a partial roughness at the interface (110) with the anchoring element (206).
9. The augment (102) of claim 7 or 8, characterized in that the surface has a smooth surface other than the interface (110) with the anchoring element (206).
10. the interface (110) for the fixation element (206) includes a portion of the circumference of the body (104) extending between the interface (106) for fixing the augment (102) to the plateau (202) and the interface (108) for fixing the augment (102) to bone; Augment (102) according to any one of the preceding claims, characterized in that the undercut extends along a portion of the periphery, in particular over the entire periphery portion.
11. A set of augments (102), The set of augments (102) comprises at least two augments (102) according to any one of claims 1 to 10, A set of augments (102), characterized in that the bodies (104) of the at least two augments (102) extend between the interface (106) for fixing the augment (102) to the plateau (202) and the interface (108) for fixing the augment (102) to the bone at different heights, or the interface (110) to the fixation elements (206) are formed for fixation elements (206) of different sizes, or the undercuts are each different in shape or angle.
12. The set comprises a first augment (102) and a second augment (102) according to any one of claims 1 to 10, the first augment (102) and the second augment (102) are positionable adjacent to each other; 12. The set of augments (102) of claim 11, wherein the interface (106) for fixing the first augment (102) to the plateau (202) of the bone implant and the interface (108) for fixing the second augment (102) to the bone are formed to join the first augment (102) and the second augment (102).
13. 13. The set of augments (102) of claim 12, wherein the second augment (102) is formed without an undercut at its interface (110) to the anchoring element (206).