Sleeve for prosthetic implant

Abstract

To provide a sleeve for a prosthetic implant having an anatomical profile.SOLUTION: The invention relates to: a sleeve (10) for a prosthetic implant (100) implantable in bone such as a femur; and related modular prosthetic assembly (200) including at least a rod (110), an intermediate neck component (112) and a sleeve (10).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sleeve for a prosthetic implant, known to those skilled in the art under the English name "sleeve", which is used in surgical procedures for the revision of a prosthetic implant, for example in the femur, when there is significant bone loss and in the metaphyseal zone it is desirable to ensure the proximal stability of the prosthetic implant. [Background technology]

[0002] Due to degenerative, congenital or traumatic diseases, such as primary osteoarthritis, secondary osteoarthritis, due to trauma, or due to infection, rheumatoid arthritis, inflammatory arthritis, osteonecrosis, bone tumors or other similar problems, it is necessary to perform joint arthroplasty surgery, which consists of the placement of a prosthetic implant or prosthesis that can generally reproduce the same movements as a healthy joint.

[0003] When revising a prosthetic implant, it is known to use a sleeve to act as a filler to fill the gap caused by the fractured primary implant.

[0004] In particular, in the case of a hip joint, the femoral prosthesis comprises a rod adapted to be inserted into the medullary canal of the femur, a substantially hemispherical head adapted to be inserted into a corresponding acetabular seat of the hip joint, and an intermediate component known to those skilled in the art by the term "neck", on one side of which the rod is connected and on the other side of which the head is connected.

[0005] In revision surgery, the sleeve is inserted into a special seat made by a surgical cutter in the proximal femur and is designed to accommodate the neck connected to the rod, providing support and ensuring correct positioning of the prosthesis. In other words, the sleeve fills the bone loss and simultaneously provides new proximal support to relieve the load on the rod, shifting the entire load to the distal side and thereby preventing stress on the modular coupling cone.

[0006] Sleeves known in the art comprise a metal body having an axial through cavity and an outer wall extending about a longitudinal axis, the entire outer wall having a cylindrical, frustoconical, or combination thereof shape, the contour of which is obtained by the rotation of one or more generatrix lines, which may be straight or dashed.

[0007] A drawback of sleeves known in the art is that the outer wall has a non-anatomical contour or is unable to follow the contour of the femur, which can result in inaccurate distribution of the load of the joint due to stress concentrations in the contact areas and resorption in the unloaded areas.

[0008] Such sleeves can result in inaccurate distribution of joint loads due to stress concentrations in the contact areas and resorption in the unloaded areas.

[0009] U.S. Patent No. 5,342,366 discloses a modular prosthetic hip joint having a removably connected rod and neck, but does not disclose a sleeve or application of the sleeve to support the modular prosthetic hip joint.

[0010] WO 01 / 43650 discloses a surgical instrument for positioning a femoral rod within a femur, the femoral rod being of one-piece construction including the neck. No. 43650 does not disclose a sleeve or application of the sleeve to support a femoral rod.

[0011] Therefore, there is a need to perfect a sleeve for a prosthetic implant that overcomes at least one of the drawbacks of the state of the art.

[0012] In particular, an object of the present invention, consistent with the technical problem to be solved, is to produce a sleeve for a prosthetic implant that has an anatomical contour.

[0013] A further object of the present invention is to create a sleeve that is minimally invasive, i.e., has a shape that is bonded to the corresponding placement bone site, meeting the requirement of removing the least possible bone material to ensure a secure seal of the prosthesis.

[0014] It is a further object of the present invention to provide a prosthetic assembly formed by the prosthetic implant and sleeve that is modular in terms of component size and easily assembled and disassembled by the surgeon.

[0015] Applicant has invented, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other objects and advantages. Summary of the Invention

[0016] The invention is set forth and characterized in the independent claims, while the dependent claims describe other features of the invention or variants of the main inventive idea.

[0017] In accordance with the above objectives, in order to solve the above disclosed technical problem in a new and original way, and which also achieves considerable advantages compared to the state of the art, a sleeve according to the invention for a prosthetic implant implantable in a bone, for example a femur, comprises an outer wall defined by a first part and a second part, said outer wall comprising, in said first part, a first outer surface obtained by rotating a first generatrix about a first longitudinal axis, and in said second part, a second outer surface obtained by rotating a second generatrix about a second longitudinal axis.

[0018] According to one aspect of the invention, the longitudinal axes are inclined relative to one another by an inclination angle.

[0019] According to one aspect of the invention, at least the second outer surface is at least partially concave towards the inside of the sleeve.

[0020] According to another aspect of the present invention, the first generating line is formed by a set of interconnected polynomials, and the second generating line is a circumferential arc, a parabola, an ellipse, a hyperbola, or a curve formed by a set of interconnected polynomials.

[0021] According to another aspect of the invention, the first generatrix is ​​a broken line and the second generatrix is ​​concave towards the inside of the sleeve and is preferably continuous.

[0022] According to another aspect of the invention, the extension of the first and second outer surfaces is variable and depends on the extension of the first and second portions, respectively.

[0023] According to another aspect of the present invention, the ratio of the extension of the first outer surface to the extension of the second outer surface is 0-5, and preferably 0.20-3.

[0024] According to another aspect of the invention, the outer surface of the outer wall may be constituted by a third outer surface in addition to the first and second outer surfaces, the third outer surface being obtained by extending the contour of the second portion along the first longitudinal axis.

[0025] According to another aspect of the invention, the rotation of the first and second generatrices generates first and second volumes that define at least the first and second outer surfaces, respectively, and the outer surface of the sleeve is formed by a portion of the outer surface of a final volume formed by the first volume and the second volume together.

[0026] According to another aspect of the invention, the portion is obtained by "cutting" the final volume along two cutting planes axially spaced apart along the first longitudinal axis.

[0027] According to another aspect of the invention, the cutting planes are parallel to each other.

[0028] According to a variant embodiment, at least one of the cut surfaces has a stepped contour, so that the cut surface defines a lateral portion that is higher, at the same level as or lower than the inner portion of the sleeve, i.e., a higher lateral portion that is at the same level as or lower than the inner portion of the sleeve.

[0029] According to another aspect of the invention, the second portion may be provided with one or more through holes, which may have a cylindrical, elliptical, or splined cross section. If present, the through holes may be positioned at a first distance of 12 to 24 mm from the first longitudinal axis and at a second distance of between 4 and 15 mm from the proximal end of the sleeve.

[0030] According to another aspect of the invention, the outer wall comprises a solid portion and a portion with a trabecular structure. Furthermore, both the solid portion and the portion with a trabecular structure are made integrally by additive printing techniques. According to a variant, the entire outer wall has a trabecular structure.

[0031] According to another aspect of the invention, the sleeve comprises an inner surface that allows for coupling with an intermediate component of the prosthetic implant, the intermediate component being configured to couple with a rod of the prosthetic implant.

[0032] According to an embodiment of the present invention, a modular prosthesis assembly comprises at least three component modules that are connectable together.

[0033] The three component modules are: - at least one intramedullary rod and an intermediate neck component that can be coupled to said rod and to a prosthesis head, said at least one intramedullary rod and said intermediate neck component being included in a prosthesis implant; a sleeve of the present invention, configured to stably couple to the mid-neck component; Includes:

[0034] According to another aspect of the invention, at least the rod, the mid-neck component, and the sleeve are distinct and separate component modules that can be connected to one another in a selectively separable manner.

[0035] According to another aspect of the present invention, the prosthesis assembly further comprises the prosthesis head.

[0036] According to another aspect of the invention, the rod, the mid-neck component, and the sleeve are provided with modular sizes. [Brief explanation of the drawings]

[0037] These and other aspects, features and advantages of the present invention will become apparent from the following description of some embodiments thereof, given by way of non-limiting example with reference to the accompanying drawings, in which: [Figure 1] Figure 1a is a side view of an assembled prosthesis assembly formed by a sleeve and coupled to a neck, which is further coupled to a head and rod forming a prosthetic implant according to the present invention, and Figure 1b is a separate component view of the prosthesis assembly of Figure 1a, shown in an exploded state. [Figure 2] FIG. 2 is a front axonometric view of the sleeve of FIGS. 1a and 1b. [Figure 3] FIG. 3 is a longitudinal cross-sectional view of the sleeve of FIG. [Figure 4] FIG. 4 is a top view of the sleeve of FIG. [Figure 5] FIG. 5 is a modification of the embodiment of FIG. [Figure 6] FIG. 6 is a modification of the embodiment of FIG. [Figure 7] FIG. 7 shows, in a combined manner, a schematic representation of the volumes that define the outer surface of the sleeve. [Figure 8] FIG. 8 shows, in a combined manner, a schematic representation of the volumes defining the outer surface of the sleeve. [Figure 9] FIG. 9 shows, in a combined manner, a schematic representation of the volumes that define the outer surface of the sleeve. [Figure 10] FIG. 10 shows, in a combined manner, a schematic representation of the volumes defining the outer surface of the sleeve. [Figure 11] FIG. 11 shows, in a combined manner, a schematic representation of the volumes that define the outer surface of the sleeve. [Figure 12] FIG. 12 shows, in a combined manner, a schematic representation of the volumes that define the outer surface of the sleeve. [Figure 13] FIG. 13 shows diagrammatically how a sleeve of the invention can be obtained from the combination of the volumes of FIGS. 7 to 12 cut along two cutting planes. [Figure 14] FIG. 14 shows diagrammatically how a sleeve of the invention can be obtained from the combination of the volumes of FIGS. 7 to 12 cut along two cutting planes. [Figure 15] FIG. 15 shows diagrammatically how a sleeve of the invention can be obtained from the combination of the volumes of FIGS. 7 to 12 cut along two cutting planes. DETAILED DESCRIPTION OF THE INVENTION

[0038] We must make it clear that the expressions and terms used in this specification, as well as the accompanying drawing figures similarly described, have the sole function of better illustrating and explaining the invention; their function is to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0039] To facilitate understanding, the same reference numbers have been used wherever possible in the drawings to identify identical common elements, and it will be understood that elements and features of one embodiment may be advantageously combined with or incorporated into other embodiments without further specification.

[0040] Referring to Figures 1a and 1b, a sleeve 10 according to the present invention is configured to support a prosthetic implant 100 inside a portion of bone (not shown) in use.

[0041] The prosthetic implant 100, together with the sleeve 10, can be easily assembled / disassembled and reassembled. This creates a prosthesis assembly 200 that is modular in terms of both component size / dimensions.

[0042] The prosthetic implant 100 described herein is, for example, a femoral prosthesis.

[0043] The prosthetic implant 100 comprises an intramedullary rod 110, which can be inserted into the medullary canal of, for example, a femur, and an intermediate component or neck 112 to which the rod 110 is connected on one side.

[0044] Furthermore, in a possible embodiment, the prosthetic implant 100 may comprise a substantially hemispherical head 111 insertable into a corresponding acetabular site in the hip joint, with the aforementioned intermediate component or neck 112 associated with the head 111 on the opposite side of the rod 110.

[0045] As clearly shown in Figure lb, the modular prosthetic assembly 200 is formed by the prosthetic implant 100 and the sleeve 10. The prosthetic implant 100 comprises separate components or modules, namely a rod 110, a neck 112, and optionally a head 111. The prosthetic implant 100 and the sleeve 10 are detachably connected to each other to form a modular structure.

[0046] The sleeve 10 defines a support for the prosthetic implant 100 at the connection zone between the rod 110 and the neck 112 .

[0047] The connections between the components may be made by interlocking, possibly with the aid of conventional mechanical locking members.

[0048] The sleeve 10 of the present invention has a configuration that is particularly suitable as a bone filler up to the inner cortical wall of the femur.

[0049] With particular reference to FIGS. 2 and 3, sleeve 10 extends between proximal and distal ends 11a, 11b and has an outer wall 13 defined by the union of first and second portions 16, 17. As shown in FIG.

[0050] The outer wall 13 extends partially circumferentially around the first longitudinal axis X on the first outer surface 13a and partially around the second longitudinal axis Y on the second outer surface 13b, inclined relative to the second longitudinal axis Y by an inclination angle γ.

[0051] The tilt angle γ is in the range of 0° to 20°, preferably 8° to 12°.

[0052] First outer surface 13a and second outer surface 13b together, or together with third outer surface 13c as described in more detail below, define the outer surface of wall 13.

[0053] Overall, sleeve 10 has an asymmetrical frusto-conical shape, whereby it is laterally wider at proximal end 11a relative to distal end 11b.

[0054] The sleeve 10 also has an inner surface 14 opposite the outer surface of the wall 13, which is coaxial with the first longitudinal axis X and defines a through hole 15 configured to receive an intermediate component 112 to which the rod 110 is connected.

[0055] The bore 15 has a substantially frustoconical longitudinal cross section that combines with the contour of the intermediate component 112 to define a shape for interfacing or interference coupling with the intermediate component 112. For example, the bore 15 may be angled from about 1° to about 20°, preferably less than 10°, and more preferably It may have a taper δ that is between about 2° and 5°.

[0056] As a result, the taper δ of the hole 15 allows the thickness of the sleeve 10 to be gradually reduced.

[0057] The inner surface 14 is substantially symmetrical about the first longitudinal axis X over its entire extension.

[0058] In contrast, one portion of the outer wall 13 is symmetrical about the first longitudinal axis X (first outer surface 13a), and another portion is symmetrical about the second longitudinal axis Y (second outer surface 13b).

[0059] A first outer surface 13a defining the outside of the first portion 16 is obtained by rotating the first generatrix A about the first longitudinal axis X.

[0060] A second outer surface 13b defining the outside of the second portion 17 is obtained by rotating the second generatrice B about the second longitudinal axis Y.

[0061] With particular reference to Figures 7-12, there are shown the volumes that define the outer surfaces 13a, 13b, 13c, which, when combined appropriately, produce the final volume that defines the contours of the outer surface of the wall 13. Figures 7a-12a and 7b-12b show the base volumes of the first and second portions 16, 17, and Figures 7c-12c show the combination of said base volumes.

[0062] As will be appreciated, the extension of first and second outer surfaces 13a and 13b is variable and depends on the extension of portions 16 and 17, respectively.

[0063] In particular, the ratio of the extension of the first outer surface 13a to the second outer surface 13b is variable, as shown, for example, in Figures 9a to 9c and Figures 10a to 10c, where the second outer surface 13b is larger than the first outer surface 13a in Figures 9a to 9c, but where the second outer surface 13b is smaller than the first outer surface 13a in Figures 10a to 10c.

[0064] According to the embodiment, the ratio of the extension of the first outer surface 13a to the second outer surface 13b can be in the range of 0-5, preferably in the range of 0.20-3.

[0065] With particular reference to Figures 8c to 12c, the outer surface of wall 13 can also be constituted by a third outer surface 13c in addition to outer surfaces 13a and 13b, which is obtained by extending the contour of second portion 17 in one or both axial directions along first longitudinal axis X (Figures 8b to 12b).

[0066] The outer surface of the sleeve 10 may consist of a portion of the outer surface of the final volume formed by the union of said elementary volumes.

[0067] Said portions can be obtained by "cutting" the final volume along two cutting planes T1, T2 axially spaced apart along a first longitudinal axis X (FIGS. 13-15).

[0068] According to an embodiment, the cutting planes T1, T2 may be parallel to each other (FIG. 13).

[0069] According to a further embodiment, at least one of the cutting surfaces T1, T2 may have a stepped profile (FIGS. 14, 15).

[0070] The cutting of the surface results in lateral portions at the same level as the inner portion of the sleeve 10 (FIG. 13), higher (FIG. 14) or lower (FIG. 15).

[0071] In other words, the surface 13 can be cut according to multiple profiles to generate new surface subsets.

[0072] According to a further aspect of the invention, the first generating line is a straight line or a spline, i.e., a curve consisting of a set of interconnected polynomials, and the second generating line is a circular arc, a parabola, an ellipse, a hyperbola, or a spline curve.

[0073] The first generatrix A may be a dashed line or a straight line inclined at an angle of, for example, about 1° to about 15° with respect to the first longitudinal axis X (FIG. 5).

[0074] In a further embodiment, the first generatrix A has an inwardly concave contour (FIG. 6).

[0075] The second generatrice B is preferably a continuous concave curve, so that the second outer surface 13b has a contour that is concave towards the inside, i.e. towards the first longitudinal axis X.

[0076] The second generating line B can be a circular arc, a parabola, an ellipse, a hyperbola, or a spline curve, i.e., a curve consisting of a set of interconnected polynomials. If the second generating line B is a circular arc, the radius of the circumference can be 20 to 200 mm.

[0077] The second portion 17 is provided with a through hole 19 extending along the transverse axis Z (FIG. 4) and adapted to receive a metal cable during reconstructive surgery of the proximal part of the femur in case of fracture.

[0078] At least a portion of the outer wall 13 may have a porous or trabecular structure to promote osseointegration of bone in contact with the sleeve 10 .

[0079] The body of the sleeve 10 is manufactured integrally by additive printing technology.

[0080] According to an embodiment, the sleeve 10 according to the invention can be used to mill a cavity obtained using a conventional milling device, more preferably using a guided milling device for prosthetic surgery, as described in WO 2021 / 186487 of the same applicant. ) are suitable for insertion into the cavity obtained using both.

[0081] It will be apparent that modifications and / or additions of components may be made to the sleeve 10 of the prosthetic implant 100 described above without departing from the scope of the present invention as defined by the claims.

[0082] It is also clear that although the present invention has been described with reference to some specific examples, a person skilled in the art can certainly realize other equivalent forms of sleeve 10 for prosthetic implant 100, which have the characteristics as recited in the claims and therefore all fall within the field of protection defined by the claims. In the following claims, the only purpose of reference signs in parentheses is to facilitate reading and they must not be considered as limiting elements with respect to the field of protection defined by the claims.

Claims

1. A sleeve (10) for a prosthetic implant (100) that can be implanted in bone, comprising: The sleeve (10) comprises an outer wall (13) defined by a first portion (16) and a second portion (17); The outer wall (13) comprises, in the first portion (16), a first outer surface (13a) obtained by rotating a first generatrix (A) about a first longitudinal axis (X), and, in the second portion (17), a second outer surface (13b) obtained by rotating a second generatrix (B) about a second longitudinal axis (Y), the longitudinal axes (X, Y) are inclined relative to one another by an inclination angle (γ), A sleeve (10) characterized in that at least said second outer surface (13b) is at least partially concave towards the inside of said sleeve (10).

2. the first bus (A) is made up of a set of interconnected polynomials; The second generating line (B) is a circumferential arc, a parabola, an ellipse, a hyperbola, or a curve consisting of a set of interconnected polynomials.

2. The sleeve (10) according to claim 1 .

3. the first generatrix (A) is a dashed line or a straight line parallel to the first longitudinal axis (X); The second generatrix (B) is concave towards the inside of the sleeve (10).

3. A sleeve (10) according to claim 1 or 2.

4. The extension of the first and second outer surfaces (13a, 13b) is variable and depends on the extension of the first and second portions (16, 17), respectively.

2. The sleeve (10) according to claim 1 .

5. The ratio of the extension of the first outer surface to the extension of the second outer surface (13a, 13b) is 0 to 5, preferably 0.20 to 3.

2. The sleeve (10) according to claim 1 .

6. The outer surface of the outer wall (13) is constituted by the first and second outer surfaces (13a, 13b) as well as a third outer surface (13c), the third outer surface (13c) being obtained by extending the contour of the second portion (17) along the first longitudinal axis (X).

2. The sleeve (10) according to claim 1 .

7. rotation of said first and second generatrices (A, B) creates first and second volumes defining at least said first and second outer surfaces (13a, 13b), respectively; The outer surface of the sleeve (10) is formed by a part of the outer surface of the final volume formed by combining the first volume and the second volume.

2. The sleeve (10) according to claim 1 .

8. The portion is obtained by "cutting" the final volume along two cutting planes (T1, T2) axially spaced apart along the first longitudinal axis (X). Sleeve (10) according to claim 7.

9. The cutting planes (T1, T2) are parallel to each other. A sleeve (10) according to claim 8.

10. At least one of the cut surfaces (T1, T2) has a stepped profile. A sleeve (10) according to claim 8.

11. The second portion (17) is provided with one or more through holes (19) which may have a cylindrical, elliptical or splined cross section.

2. The sleeve (10) according to claim 1 .

12. The outer wall (13) includes a solid portion and a portion having a trabecular structure, Both the solid portion and the portion with the trabecular structure are made integrally by additive printing techniques.

2. The sleeve (10) according to claim 1 .

13. The entire outer wall (13) has a trabecular structure and is made integrally by additive printing technology.

2. The sleeve (10) according to claim 1 .

14. It has an inner surface (14) that allows for coupling with an intermediate component (112) of the prosthetic implant (100), the intermediate component (112) being configured to couple with the rod (110) of the prosthetic implant (100).

2. The sleeve (10) according to claim 1 .

15. at least three component modules (10, 110, 112) connectable together, said three component modules (10, 110, 112) comprising: - at least one intramedullary rod (110) and an intermediate neck component (112) that can be coupled to said rod (110) and to a prosthesis head (111), said at least one intramedullary rod (110) and said intermediate neck component (112) being included in a prosthetic implant (100); - a sleeve (10) according to claim 1, which is adapted to be stably coupled to said intermediate neck component (112); A modular prosthesis assembly (200) comprising:

16. At least the rod (110), the mid-neck component (112), and the sleeve (10) are distinct and separate component modules that can be connected to one another in a selectively separable manner.

16. The modular prosthesis assembly (200) of claim 15.

17. 16. The modular prosthesis assembly (200) of claim 15, further comprising the prosthesis head (111).

18. 16. The modular prosthesis assembly (200) of claim 15, wherein the rod (110), the mid-neck component (112), and the sleeve (10) comprise modular sizes.

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