Bone fixation implant with cortical stabilization

Abstract

Bone-anchored implants with cortical stabilization The present invention relates to a bone fixation implant with cortical stabilization, comprising an expandable sleeve (2) having an internal first thread (20) and an external second thread (21), and a screw (1) having an external thread (11) with an external profile complementary to the internal profile of the expandable sleeve (2) and with an opposite thread pitch to the second thread (21). The implant switches from a collapsed rest position to an expanded position by actuating the reverse screw, which penetrates the screw (1) into the expandable sleeve (2) and causes radial expansion of the expandable sleeve (2) by deformation at the distal portion. In the deployed position, the expandable sleeve (2) has a frusto-conical shape. The proximal portion of the screw (1) includes an outer bone anchoring thread (15) and a frusto-conical portion that expands in the opposite direction to the expansion of the expandable sleeve (2) in the deployed position.

Description

Technical Field

[0001] The present invention relates to bone implants for dental, orthopedic, surgical, or bone shaping applications, with or without plates, such as dental or ligament implants for joints such as the lumbar spine, elbow, ankle, shoulder, and knee, or spinal bone implants for vertebrae, for example. These fields of application are given by way of example and are not intended to limit the scope of the present invention.

[0002] More specifically, the present invention relates to bone implants that are very stable when implanted into porous bone.

Background Art

[0003] Bone fixation implants generally consist of an elongated body intended to be implanted into a housing formed within bone tissue, such as the jawbone or vertebrae, for dental applications.

[0004] Bone fixation implants can be easily introduced into bone tissue without causing damage, and it is important that the fixation device within the bone tissue is stable. In fact, current bone fixation implant devices cannot be fixed without causing more cracks or damage in the bone tissue than required by the size of the device itself, and furthermore, many current treatment techniques rely on bone growth, which requires that the device fixed within the bone tissue remains immobile as much as possible. Therefore, it is necessary that the fixation of the bone implant is reliable and very stable.

[0005] Furthermore, in order to avoid the risk of incorrect positioning of the bone implant, which can be caused particularly by its positioning or implantation within the bone, it is also necessary that the implantation into the bone tissue is easy to perform.

[0006] Furthermore, in the case of a fall, impact, or accident, it is important that the implant remains in its predetermined position within the bone tissue, i.e., does not move through the bone. For this purpose, the implant requires very high stability.

[0007] The state of the art includes the patent document EP2603163(B1), which describes an intramedullary implant with improved fixation that can be implanted into bone tissue. This intramedullary implant includes a fixation device having a portion called a gripping portion within the bone tissue and a portion called an expansion portion, and these two portions are relatively movable. The invention referred to in this patent also includes cooperating mechanical connection means disposed on the gripping portion on one hand and on the expansion portion on the other hand. As a result, the relative mobility of the two parts has at least one degree of freedom, and the relative displacement of the two parts expands the gripping portion, and this expansion causes the gripping portion to grip within the bone tissue. The bone implant described in this patent is particularly found in applications in the dental field.

[0008] However, such a solution has the drawback that, while the bone implant is fixed so as not to rotate and translate within the tissue, there is a risk of movement, particularly backward movement, during impact.

[0009] Therefore, the object of the present invention is to solve these drawbacks by proposing a bone implant that can be implanted and fixed within bone tissue in a very stable manner. SUMMARY OF THE INVENTION

[0010] Therefore, the object of the present invention is to overcome the drawbacks of the prior art by proposing a bone fixation implant, hereinafter referred to as a bone implant, which can be easily implanted into bone tissue and is stable.

[0011] To achieve this result, the present invention relates to a bone fixation implant with cortical stabilization that can be implanted into bone tissue, and this implant An expandable sleeve extending between a proximal portion having a first inner diameter and a distal portion having a second inner diameter smaller than the first inner diameter, the two portions defining a longitudinal axis (L), the first and second inner diameters defining an inner profile of the expandable sleeve, the expandable sleeve comprising, on the one hand, at least a first thread on the inside of the expandable sleeve and, on the other hand, at least a second thread on the outside of the expandable sleeve. A screw body extending between the proximal portion and the distal portion, having, on the one hand, an outer profile complementary to the inner profile of the expandable sleeve along the longitudinal axis and, on the other hand, at least one outer thread with a screw pitch opposite to that of the second outer thread of the expandable sleeve. The implant can be switched from a folded rest position to a deployed position by the operation of the reverse threads by passing a screw through the expandable sleeve and deforming the expandable sleeve due to the fact that the outer diameter of the screw is larger than the second inner diameter of the expandable sleeve at least in the distal portion by at least one constriction. In the deployed position of the implant, the second inner diameter of the expandable sleeve is greater than or equal to the first proximal diameter of the sleeve. The sleeve has a cylindrical or frustoconical portion obtained by expansion. The implant has a proximal frustoconical portion that widens towards the proximal portion near the proximal portion of the implant in the deployed position, and this proximal frustoconical portion is formed by the outer profile of the sleeve, or by the outer profile of the screw body, or by the complementary shape of the outer profiles of the sleeve and the screw body in the deployed position. formed in any of these ways. The proximal frustoconical portion has outer bone fixation threads around its circumference.

[0012] According to one feature, the at least one constriction is located at a distance determined according to the depth within the bone tissue where expansion is desired, relative to the proximal portion and along the longitudinal axis.

[0013] According to one feature, the screw is configured to be implanted into the bone tissue by being embedded inside an expandable sleeve, the proximal portion of the screw including an outer bone fixation thread being adapted to be implanted into the bone tissue, having a frustoconical outer profile on the proximal portion of the screw, and the conical opening angle of the frustoconical outer profile being opposite to the conical opening angle of the frustoconical portion of the expandable sleeve in the deployed position.

[0014] According to another feature, the screw is configured to be implanted into the bone tissue by being embedded inside an expandable sleeve, the proximal portion having an outer bone fixation thread being configured to be implanted into the bone tissue, and having an outer cylindrical profile on the proximal portion.

[0015] According to another feature, the frustoconical portion of the proximal portion of the expandable sleeve and the frustoconical outer profile of the screw are arranged opposite to each other.

[0016] According to another feature, the angle of the frustoconical portion of the proximal portion of the expandable sleeve is larger than the angle of the frustoconical outer profile of the screw, allowing for a greater spread and improving the basic quality.

[0017] According to another feature, the screw comprises at least one distance marker to visualize the point in time when the screwing of the screw into the expandable sleeve must be performed in a direction opposite to the screwing of the expandable sleeve into the bone tissue.

[0018] According to another feature, the thread height of the second outer thread of the expandable sleeve is greater than the thread height of the first thread inside the expandable sleeve and the thread height of the mechanical thread of the outer thread of the screw.

[0019] According to another feature, the distal portion of the expandable sleeve has a frustoconical portion including a thread with a conical core that allows the expandable sleeve to be deeply embedded in the bone.

[0020] According to another feature, the distal portion includes a self-tapping notch.

[0021] According to another feature, the expandable sleeve includes longitudinal through slots extending to its distal portion.

[0022] According to another feature, there are the same number of self-tapping notches as the longitudinal through slots.

[0023] According to another feature, the expandable sleeve includes longitudinal non-through slots.

[0024] According to another feature, the screw has a tip including at least one rear groove with a cutting edge at the distal portion of the screw, and the angle of the cutting edge with respect to the longitudinal axis defined by the two end portions, which extends between the proximal portion and the distal portion of the expandable sleeve, is determined as a function of the rotational direction of the screw when loosening the screw from the deployed position to the rest position, and cuts the bone during the extraction of the bone implant.

Brief Description of the Drawings

[0025] Other features and advantages of the present invention will become apparent by reading the detailed description of the embodiments of the present invention, which are merely examples, and referring to the following drawings.

Figure 1a

Figure 1b

Figure 2

Figure 3a

Figure 3b

Figure 3c

Figure 4a

Figure 4b

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10a

Figure 10b

Figure 11

Figure 12

Figure 13

DETAILED DESCRIPTION OF THE INVENTION

[0026] Various embodiments of the present invention will be described below with reference to the accompanying drawings, which are by way of example and not limitation.

[0027] This application relates to the implantation of bone implants into bone tissue.

[0028] It should be noted that in this specification, the term "implantation" generally indicates the fact of introducing a bone implant into bone tissue by screwing. The implantation proposed in this application indicates a sufficiently firm and stable introduction of the bone implant to ensure good maintenance of the bone implant within the bone tissue.

[0029] In addition, the term "bone tissue(s)" generally refers to all types of bone, whether cortical (compact bone or periosteum) or cancellous (soft, porous) bone, since the bone implant system of this application can be implanted into any type of bone tissue.

[0030] Furthermore, the terms used should not be construed in their ordinary meaning, but should be construed in light of the functional considerations detailed in this application.

[0031] Figures 1a, 1b, and 2 are exemplary and non-limiting illustrative embodiments of a bone implant.

[0032] For example, as shown in Figures 1a, 1b, and 2, a bone implant that can be implanted into bone tissue includes an expandable sleeve (2) extending between a proximal portion (22) and a distal portion (23), these two portions defining a longitudinal axis (L), and the expandable sleeve includes, on the one hand, at least a first thread (20) inside the expandable sleeve (2) and, on the other hand, at least a second thread (21) outside the expandable sleeve (2).

[0033] The terms "proximal" and "distal" in this application respectively refer to the portion where the implant device is held to enable implantation into bone tissue and the portion that is first implanted into the bone tissue (opposite the proximal portion).

[0034] In this application, the terms "proximal part and distal part" refer to the parts located near the distal end and the proximal end.

[0035] In this application, the term "expandable sleeve (2)" generally refers to a hollow general cylinder.

[0036] In some embodiments, the bone implant also includes a screw (1) extending between a proximal part (12) and a distal part (13) on an axis collinear with the axis (L). On the one hand, along the longitudinal axis (L), it has an outer profile complementary to the inner profile of the expandable sleeve (2). On the other hand, it has at least one outer thread (11) with a thread pitch opposite to the second outer thread (21) of the expandable sleeve (2).

[0037] Note that the proximal part (12) of the screw (1) is directly implanted into the cortical bone.

[0038] In some embodiments, the proximal end of the screw (1) is provided with actuating means that enable the screw (1) to be screwed in. The actuating means has a structure of any shape desired by the operator according to its use, for example, as shown in Figure 1b. The actuating means is, for example, a hexagonal hole or a torx or a cross or any other actuating means. The proximal end of the screw (1) can have various shapes (a head for fixing a multi-axis or non-multi-axis bone joint bar, or for fixing a plate or any other device) according to the desired target location of the bone fixation implant.

[0039] In some embodiments, the screw (1) is provided with a cannula passing through the screw (1) that enables the operator to inject cement, for example, as needed.

[0040] Note that the bone implant is made of titanium or implantable medical stainless steel, or polyetheretherketone (PEEK), or polyetherketoneketone (PEKK), or any other material that a person skilled in the art can determine to be suitable according to its mechanical and physicochemical properties and biocompatibility.

[0041] In some embodiments, the screw (1) comprises a cannula passing through the screw (1) that enables the operator to inject cement, for example, as needed.

[0042] In some embodiments, the second thread (21) on the outside of the expandable sleeve (2) enables bone fixation. As used in this application, the term "bone fixation" generally refers to various types of devices that include at least one element intended to enter the bone tissue along a linear path under a pressing action in the form of a repetitive screwing motion, impact, or hammering. Bone fixation screws are generally known to have a higher thread height than machine screws to ensure better fixation. In addition, bone fixation screws, unlike machine screws in general, can be varied in core diameter, thread pitch, and wire height by a person skilled in the art according to the type of bone and the desired application, and this application encompasses these various embodiments. The thread height of the second outer thread (21) of the expandable sleeve (2) is greater than the thread height of the machine threads of the first thread (20) inside the expandable sleeve (2) and the outer thread (11) of the screw (1). Therefore, the second thread (21) has an edge higher than the first thread (20), enabling the bone implant to enter and be fixed in the bone.

[0043] Furthermore, in some embodiments, some machine screws, such as trapezoidal screws, have less resistance and facilitate the penetration of the screw (1) into the expandable sleeve (2) fixed in the bone. Trapezoidal screws also enable the distribution of a large load on the bone tissue under compression on the bone implant.

[0044] In some embodiments, the distal portion (23) of the expandable sleeve (2) has a frustoconical portion (291) with a thread (232) having a conical core that allows the expandable sleeve (2) to be deeply embedded in bone, as shown, for example, in FIGS. 1a - 4b.

[0045] In some embodiments, the distal portion (23) of the sleeve (2) is self - tapping and includes, for example, self - tapping (milling and tapping) notches (231) as shown in FIGS. 3a - 4b. This distal portion (23) allows avoiding pre - drilling before implant insertion and maintaining bone during implantation, thus being able to retain the maximum amount of bone around the implanted area and improving the stability of the bone implant. In fact, the time for osseointegration is shortened and the need to add any type of bone filling material, whether synthetic or natural, is reduced. Additionally, the distribution of the notches (231) ensures a good balance across each of the portions of the distal portion (23), guaranteeing good uniformity of the force distribution during the insertion of the implant into the bone tissue.

[0046] In some embodiments, the screw (1) includes at least one distance marker (16), for example, as shown in FIG. 2, to visualize the point in time when the screwing of the screw (1) into the expandable sleeve (2) must be performed in a direction opposite to the screwing of the expandable sleeve (2) into the bone tissue.

[0047] In some embodiments, the distance marker (16) is a laser marker.

[0048] In some embodiments, placing the implant comprises the following screwing the bone implant in the direction of the outer thread (21) until the distance marker (16) is flush with the surface of the bone cortex, and screwing the bone implant in the direction of the second thread (11) to complete the screwing of the threaded screw (1) into the bone and advancing the expansion of the expandable sleeve (2).

[0049] In some variations of the present invention, the cortical bone is perforated by a cortical preforming tool.

[0050] This application also relates to the expansion of bone implants within bone tissue.

[0051] In some embodiments, the outer profile of the screw (1) and the inner profile of the expandable sleeve (2) are complementary, such that their profiles, in the expanded configuration, a proximal bearing supported by the complementarity of the inner diameter of the expandable sleeve (2) and the outer diameter of the screw (1), and a distal bearing supported by the cooperation of the expandable sleeve (2) and the screw (1), which narrows towards the distal portion until the inner diameter of the expandable sleeve is smaller than the outer diameter of the screw (1), a "central" bearing located between the two bearings, formed by the cooperation between the outer diameter of the screw (1) and the inner diameter of the expandable sleeve (2), thereby making the outer diameter of the expandable sleeve (2) at the "central" position larger than the outer diameter of the expandable sleeve (2) at the proximal bearing, resulting in a "central" bearing.

[0052] In some embodiments, for example, as shown in FIGS. 4a and 4b, the implant can be switched from a folded rest position to a deployed position by expanding the expandable sleeve (2) by deformation, due to the fact that the outer diameter of the screw (1) is larger than the inner diameter of the expandable sleeve (2) at least at one constriction (271) in the distal portion, by the operation of a reverse thread, by passing the screw (1) through the expandable sleeve (2).

[0053] In some embodiments, the constriction portion (271) is positioned at a distance determined according to the depth within the bone tissue where expansion is desired, relative to the proximal portion and along the longitudinal axis (L). It should be noted that this distance is determined by the operator himself, especially with respect to the cortical bone and / or the desired compression, as shown, for example, in FIGS. 4a and 4b.

[0054] In some embodiments, the duct in the middle portion between the proximal end and the distal end of the expandable sleeve (2) has a diameter difference that is larger than the diameter of the location where the central support portion is located.

[0055] In some embodiments, the duct of the expandable sleeve (2) in the middle portion between the proximal end and the distal end has a discontinuous gradient. Thus, the constriction portion (271) is located at a variable distance from the proximal end, for example, according to the type of bone, and can provide expansion at various depths.

[0056] In some embodiments, the proximal portion of the screw (1) includes an outer bone fixation thread (15), as shown, for example, in FIGS. 1a, 1b, and 2.

[0057] In some embodiments, the screw (1) is configured to be implanted into the bone tissue by being embedded inside the expandable sleeve (2). The proximal portion of the screw (1) including the outer bone fixation thread (15) is adapted to be implanted into the bone tissue and has a frustoconical portion that expands inversely with respect to the expansion of the proximal portion of the expandable sleeve (2) in the deployed position, as shown, for example, in FIG. 11. This reversal of the expansion of the two frustoconical shapes requires compression and / or friction that improves the stability of the implant, especially due to the fact that these two frustoconical shapes are located around the cortical bone.

[0058] In some embodiments, the screw (1) is configured to be implanted into bone tissue by being embedded inside an expandable sleeve (2), and the proximal portion of the screw (1) including the outer bone fixation thread (15) is adapted to be implanted into bone tissue and has a cylindrical portion or any offset shape.

[0059] The resulting opposing reverse frustum cones enable the progressive implantation of the implant by distributing the force of the bone implant within the bone tissue during implantation and enable the transmission of force on the conical surface rather than on a cylindrical line. Further, the opposing reverse frustum cones ensure axial locking with respect to the cortical portion of the densest vertebrae. Thus, it contributes to a very high stability of the bone implant in the bone tissue.

[0060] In some embodiments, for example, as shown in FIG. 3a, the expandable sleeve (2) has an acute angle α at the end of the distal portion (23). This angle α increases in spread as the screw (1) enters the expandable sleeve (2) during expansion.

[0061] In some embodiments, for example, as shown in FIG. 3b, the angle α becomes a gradually increasing spread angle β during expansion, and the angle β is the angle of the expanded expandable sleeve (2).

[0062] In some embodiments, for example, as shown in FIG. 3c, the cortical portion compresses the bone implant, and the cortical portion has an angle γ that is held by the expandable sleeve (2), or the screw (1), or both. The angle α becomes the angle β of the expandable sleeve (2) by gradually spreading and is opposite to the angle γ.

[0063] It should be noted that in the deployed position, the walls of the expandable sleeve (2) can be parallel instead of forming an angle β in some embodiments.

[0064] In some embodiments, the expandable sleeve (2) has a dome shape at the central support due to the presence of angles α and β, as shown for example in FIG. 5.

[0065] In fact, in some embodiments, the implant, as shown for example in FIGS. 1a, 1b, 4a, 4b, 6, and 8 - 10, on the one hand, has a stationary configuration in which the abutment mechanism (26) meshes the expandable sleeve (2) and the screw body (1) by reversing the respective thread pitches of these two, and on the other hand, the complementary inner and outer threads of the expandable sleeve (2) and the screw (1) operate with each other to pass the screw (1) through the expandable sleeve (2), and during the passage of the screw (1) through the expandable sleeve (2), the outer diameter of the screw (1) which is larger than the inner diameter of the expandable sleeve (2) causes the expansion of the expandable sleeve (2) at least in the distal part by the deformation of the expandable sleeve (2), and is expandable between the expansion configurations thus obtained.

[0066] In some embodiments, at the deployed position of the implant, the second distal diameter of the expandable sleeve (2) is greater than or equal to the first proximal diameter of the sleeve (2), so the sleeve (2) has a cylindrical or frustoconical part obtained by expansion.

[0067] The implant has a proximal frustoconical part that widens towards the proximal part near the proximal part of the implant in the deployed position, and this proximal frustoconical part For example, in the mode where the angle γ is held by the expandable sleeve (2) as shown in FIG. 3c, by the outer profile of the expandable sleeve (2), Or, for example, in the mode where the angle γ is held by the screw (1) as shown in FIG. 5, by the outer profile of the screw body (1), Or, for example, in the mode where the angle γ is held by the screw (1) and the expandable sleeve (2) as shown in FIG. 13, at the deployed position, by the complementary shape of the outer profiles of the sleeve (2) and the screw body (1), It is formed by any one of them.

[0068] The proximal frustoconical portion has outer bone fixation threads (15, 215) around it.

[0069] In some embodiments, in the deployed position of the implant, the expandable sleeve (2) has a frustoconical shape in at least one proximal portion (22), for example, as shown in FIGS. 5 to 10b, and expands towards the distal portion of the screw (1) near the proximal portion of the screw (1).

[0070] In some embodiments, the expandable sleeve (2) has a cylindrical or conical shape in at least one proximal portion (22).

[0071] In some embodiments, the screw (1) has a tip (17) at the tip of the distal portion (13), for example, as shown in FIGS. 1a, 1b, 2, 5, 10a, 10b, and 12, and its outer profile is complementary to the inner profile of the distal portion (23) of the expandable sleeve (2).

[0072] In some embodiments, the frustoconical portion of the proximal portion of the expandable sleeve (2) and the frustoconical outer profile of the screw (1) are arranged in contact end-to-end or facing each other, connected to the proximal portion (22) of the expandable sleeve (2), and the angle of the frustoconical portion of the proximal portion of the expandable sleeve (2) is larger than the angle of the frustoconical outer profile of the screw (1), allowing for a larger spread and / or facilitating overall expansion.

[0073] In some embodiments, for example, as shown in FIGS. 2, 3, 5, 6, 7, and 8, the expandable sleeve (2) includes a longitudinal through slot (24) extending to its distal portion (23) and a longitudinal non-through slot (25) that enables expansion of the expandable sleeve (2). There are several through slots (24) or non-through slots (25), and it is preferred that the distal portion (23) includes two types of slots, namely, the longitudinal through slot (24) and the longitudinal non-through slot (25).

[0074] In some embodiments, the synergistic effect between the through slot (24) and the non-through slot (25) also enables a frustoconical shape and / or a dome shape in the deployed position.

[0075] In some embodiments, there are as many self-tapping notches (231) as there are longitudinal through slots (24).

[0076] In some embodiments, the through slot (24) and the non-through slot (25) are offset from each other over the length of the expandable sleeve (2). The offset between the through slot (24) and the non-through slot (25) over the length improves the flexibility and mechanical strength of the expandable sleeve (2) during expansion.

[0077] In some variations of the present invention, the bone fixation portions (15, 215) can be extended.

[0078] In some embodiments, the longitudinal through slots (24) and non-through slots (25) of the distal portion (23) allow for the cylindrical expansion of the expandable sleeve (2). The longitudinal non-through slots (25) make it possible to maintain the contact profile on the three bearing portions between the expandable sleeve (2) and the screw (1) during expansion, and by evenly distributing the force due to expansion over the outer circumference of the expanded expandable sleeve (2), contribute to the stability of the bone implant within the bone tissue. The longitudinal through slots (24) and non-through slots (25) allow for the radial expansion of the proximal portion (22) of the expandable sleeve (2) by corresponding to the elastic limit of the material of the expandable sleeve (2) and its elastic contraction during loosening of the screw.

[0079] In some embodiments, the longitudinal through slot (24) extends over 10% to 90% of the length of the expandable sleeve (2).

[0080] In some embodiments, for example, as shown in Figure 3a, the portion of the expandable sleeve (2) includes a taper angle alpha (α) at the bottom of the screw, and the shape of the expandable sleeve (2) ensures the automatic centering of the expandable sleeve (2) within the cavity formed by the anatomical conical preform tool during the screwing operation.

[0081] According to one alternative embodiment (not shown), the screw (1) does not include a cortical screw portion. This variant makes it possible to produce an assembly of a shorter screw (1) and an expandable sleeve (2) adapted to other implantation situations.

[0082] One skilled in the art will understand that various types of tips and structures can be added to the proximal portion of the screw (1) for this purpose and according to other assembly modes by adapting the shape of this portion according to the purpose of the implant. By way of non-limiting example, these assemblies can be made by screwing, clip fastening, key fastening, joining, or welding.

[0083] Therefore, the bone implant proposed in the present invention can be quickly and accurately implanted into bone tissue and can maintain the implanted state in the bone tissue in a very stable manner.

[0084] This application describes various technical features and advantages with reference to the drawings and / or various embodiments. A person skilled in the art will understand that, unless explicitly stated to the contrary, or these characteristics are incompatible, or the combination does not function, in fact, the technical features of a given embodiment can be combined with the features of one or more other embodiments.

[0085] More generally, combinations of various types of implant retention means and / or spinal retention means are envisioned and will be understood by those skilled in the art using the functional and structural considerations provided in this application. Furthermore, in particular, the functional considerations provided in this application provide sufficient explanation such that the required structural adaptations are within the scope of those skilled in the art. Therefore, the technical features described in a given embodiment can be separated from the other features of this mode, unless explicitly stated to the contrary.

[0086] A person skilled in the art will understand that, upon reading this application, many specific forms of embodiments other than those described in detail are possible without departing from the scope of the invention claimed. Therefore, this embodiment should be considered as illustrative, but can be modified in the field defined by the appended claims, and the present invention should not be limited to the above details.

Claims

1. An osteosynthesis implant with cortical stabilization that can be implanted into fixed tissue, comprising: An expandable sleeve (2) extending between a proximal portion (22) having a first inner diameter and a distal portion (23) having a second inner diameter smaller than the first inner diameter, the two portions defining a longitudinal axis (L), the first and second inner diameters defining an inner profile of the expandable sleeve (2), the expandable sleeve (2) having, on the one hand, at least a first thread (20) inside the expandable sleeve (2) and, on the other hand, at least a second thread (21) outside the expandable sleeve (2); A screw body (1) extending between a proximal portion (12) and a distal portion (13), having, on the one hand, an outer profile complementary to the inner profile of the expandable sleeve (2) along the longitudinal axis (L) and, on the other hand, at least one outer thread (11) with a screw pitch opposite to that of the second outer thread (21) of the expandable sleeve (2); The implant can be switched from a folded rest position to a deployed position by passing the screw (1) through the expandable sleeve (2) and expanding the expandable sleeve (2) by deformation due to the fact that the outer diameter of the screw (1) is larger than the second inner diameter of the expandable sleeve (2) by at least one constriction (271), at least in the distal portion, by the operation of the reverse screw; In the deployed position of the implant, the second inner diameter of the expandable sleeve (2) is greater than or equal to the first proximal diameter of the sleeve; In an osteosynthesis implant with cortical stabilization, The sleeve has a cylindrical or frustoconical portion obtained by the expansion; The implant has a proximal frustoconical portion that widens towards the proximal portion, near the proximal portion of the implant in the deployed position, the proximal frustoconical portion being Defined by the outer profile of the sleeve (2), Or by the outer profile of the screw body (1), Or by the complementary shape of the outer profiles of the sleeve (2) and the screw body (1) in the deployed position. formed by any of the proximal frustoconical portion having outer bone fixation threads (15, 252) around it, a bone fixation implant, characterized in that. **Claim 2** The at least one constriction (271) is located at a distance determined according to the depth in the bone tissue where the expansion is desired along the longitudinal axis (L) with respect to the proximal portion, the implant according to claim 1, characterized in that. **Claim 3** The screw (1) is configured to be implanted into the bone tissue by being embedded inside the expandable sleeve (2), the proximal portion of the screw (1) including the outer bone fixation threads (15) is configured to be implanted into the bone tissue, having a frustoconical outer profile on the proximal portion of the screw (1), the conical opening angle of the frustoconical outer profile being opposite to the conical opening angle of the frustoconical portion of the expandable sleeve (2) in the deployed position, the implant according to combined claim 1 or 2, characterized in that. **Claim 4** The screw (1) is configured to be implanted into the bone tissue by being embedded inside the expandable sleeve (2), the proximal portion of the screw (1) including the outer bone fixation threads (15) is configured to be implanted into the bone tissue, having an outer cylindrical profile on the proximal portion of the screw (1), the implant according to any one of combined claims 1 to 3, characterized in that. **Claim 5** The frustoconical portion of the proximal portion of the expandable sleeve (2) and the frustoconical outer profile of the screw (1) are arranged facing each other, the implant according to claim 3, characterized in that. **Claim 6** The angle of the frustoconical portion of the proximal portion of the expandable sleeve (2) is larger than the angle of the frustoconical outer profile of the screw (1), allowing a larger spread and improving basic stability, the implant according to claim 5, characterized in that. **Claim 7** The implant according to claim 6, characterized in that the screw (1) comprises at least one distance marker (16) in order to visualize the point in time when the screwing of the screw (1) into the expandable sleeve (2) must be carried out in a direction opposite to the screwing of the expandable sleeve (2) into the bone tissue.

8. The implant according to any one of the combined claims 1 to 7, characterized in that the thread height of the second outer thread (21) of the expandable sleeve (2) is greater than the thread height of the mechanical threads of the first thread (20) inside the expandable sleeve (2) and the outer thread (11) of the screw (1).

9. The implant according to any one of the combined claims 1 to 8, characterized in that the distal part (23) of the expandable sleeve (2) has a frustoconical part (291) with a thread (232) having a conical core, enabling the expandable sleeve (2) to be deeply implanted into the bone.

10. The implant according to any one of the combined claims 1 to 9, characterized in that the distal part (23) includes a self-tapping notch (231).

11. The implant according to any one of the combined claims 1 to 10, characterized in that the expandable sleeve (2) includes a longitudinal through slot (24) extending to the distal part (23).

12. The implant according to claim 11, characterized in that there are as many self-tapping notches (231) as there are longitudinal through slots (24).

13. The implant according to any one of the combined claims 1 to 12, characterized in that the expandable sleeve (2) includes a longitudinal non-through slot (25).

14. The implant according to claim 9, characterized in that the screw (1) has a tip at its distal part (17) that includes at least one rear groove (171) having a cutting edge, and the angle of the cutting edge with respect to the longitudinal axis (L) defined by the two end parts, which extends between the proximal part (22) and the distal part (23) of the expandable sleeve (2), is determined according to the rotational direction of the screw (1) during loosening of the screw from the deployed position to the rest position, and cuts the bone during extraction of the bone implant.

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