Bone plate and adapted insert

Abstract

An insert (3) for a bone plate (2) having a through-hole for the plate (23), said insert having a central tapped through-hole (34) intended to cooperate with a thread (43) of a bone anchoring device (4), said insert further having a shoulder (33) and elastic interlocking means (32) cooperating with the plate hole for being embedded therein, said insert being manufactured by subtractive manufacturing. Figure to be published: Figure 2

Description

Title of the invention: Bone plate and adapted insert Technical field

[0001] The field of the invention is that of bone plates suitable for use in carrying out osteosynthesis. The field of the invention is more particularly that of bone plates for the treatment of pathologies affecting the skeletal system, whether animal or human. State of the prior art

[0002] The most widely used technical solutions today for the treatment of pathologies affecting the skeletal system in human or veterinary bone surgery (orthopedic, traumatological, dental, cranio-maxillofacial, spine and oncology-orthopedic etc.) consist of a retention system combining one or more plates and screws, most often metallic, intended to be anchored in the bone(s) in question. This system is thus dedicated to being fixed to healthy and / or damaged bone surfaces, in order to ensure the stability of these areas and the compression of the bone fragments which will ultimately allow the reconstruction and consolidation of the bone in question (long bone, cranial bone, spinal bone, etc.).

[0003] These bone retention plates are therefore positioned against or close to the surface of the bones to be treated, their design and sizing being closely linked to two factors: on the one hand the bone anatomy of the patient and on the other hand the nature and location of the pathology.

[0004] There is indeed significant anatomical variability of the inter- and intra-population skeleton requiring the definition of wide dimensional intervals as well as dedicated designs for the restraint systems in order to respond to all the situations encountered by practitioners.

[0005] The variability of the designs must also integrate the high number of typologies of skeletal pathologies recorded (long bones, spinal bones, simple or complex fracture, extra-articular or intra-articular, transverse, multi-fragmentary, osteotomies, etc.).

[0006] The consequence of all these requirements, increased by the varied possibilities of manufacturing materials, is today the availability of a plethora of osteosynthesis devices. It is thus not uncommon for a practitioner to have to choose during the intervention between several dozen plates and screws to carry out his intervention, associated with several instruments specially designed for the placement of the associated implants. In addition to the time that the practitioner must take to refine his preoperative analysis in order to determine the references he needs among the dozens of options on offer, it is necessary to integrate, upstream and downstream, the burden of managing this stock, whether it is the financial and administrative impact or the management of cleaning and sterilization of these devices. Due to the historical choice of the plethora of offers to meet all the needs of practitioners, the operational impact for healthcare establishments is inseparable from the analysis.

[0007] There are different models of plates: so-called "locked" plates having threaded holes allowing contention of the bone without contact with the latter by means of screws having threaded heads and so-called "compression" plates where the screws compress the plate against the surface of the bone. The use of locked screws with machined plates is well known and has advantages, such as stability of the plate from the insertion of the first screw, preservation of the periosteum by avoiding its compression, and a lower fixation failure rate compared to compression fixations.

[0008] The present description proposes a simple solution for the installation of screw locking on a personalized plate produced by additive manufacturing.

[0009] The use of machining tools to shape a geometrically customized plate proves to be expensive and time-consuming compared to plates produced by additive manufacturing.

[0010] One aim of the invention is in particular to remedy all or part of the aforementioned drawbacks. Statement of the invention

[0011] For this purpose and according to a first aspect, the invention is an insert for a personalized bone plate having a through plate hole, the insert comprising a central threaded through hole provided to cooperate with a thread of a bone anchoring device, the insert further comprising a shoulder and elastic fitting means cooperating with the plate hole to be embedded therein, the insert being manufactured by subtractive manufacturing.

[0012] Advantageously, the insert may have a truncated seat adapted to receive a truncated head of a bone anchor.

[0013] According to a second aspect of the invention, there is provided a retention assembly comprising: a customized bone plate having a through plate hole and an insert according to the first aspect of the invention, or one or more of its improvements. The insert is embedded in the bone plate hole by elastic fitting. The bone plate is manufactured by additive manufacturing and said insert is preferably manufactured by subtractive manufacturing. Preferably, the elastic fitting is irreversible.

[0014] Preferably, the insert has a flank comprising a flat cooperating with a bearing surface of the bone plate.

[0015] The retention assembly may further comprise a bone anchoring device having a thread cooperating with the central threaded through hole.

[0016] According to another aspect of the invention, there is provided a method of assembling a bone anchor having a thread in a personalized bone plate having a through plate hole, the bone plate being obtained by additive manufacturing, the method comprising a step of embedding by elastic fitting of an insert manufactured by subtractive manufacturing, the insert comprising a tapped through central hole provided to cooperate with the thread, the insert further comprising a shoulder and elastic fitting means cooperating with the plate hole to be embedded therein. Description of figures

[0017] Other advantages and particularities of the invention will appear on reading the detailed description of implementations and embodiments which are in no way limiting, with regard to the appended drawings in which: • [Fig.l] represents, in a perspective view, an example of a restraint assembly according to the invention; • [Fig.2] is a section of the assembly shown in [Fig.l]; • [Fig.3] represents a perspective view of an insert according to a method of realization of the invention. Description of embodiments

[0018] The embodiments described below being in no way limiting, it will be possible in particular to consider variants of the invention comprising only a selection of the characteristics described, subsequently isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection comprises at least one characteristic, preferably functional without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0019] In the figures, an element appearing in several figures retains the same reference.

[0020] The retention assembly 1 comprises a bone plate 2, an insert 3 for a bone plate according to one embodiment of the invention and a bone anchoring device 4.

[0021] Bone plate

[0022] The bone plate 2 is advantageously a plate specific to the geometry of a patient's bone, in the reduced and corrected position of the bone. It is then adapted to the patient's bone. The plate may be specific to a patient according to other aspects: the pathology treated, the location planned for the plate, the number of holes, the type of holes, a local change in the width or thickness of the plate, etc. A surface of the bone plate 2 may thus be congruent, totally or partially, to a surface of a patient's bone.

[0023] Preferably, the plate defines a surface corresponding to exterior surfaces of the bone. Optionally, the plate may have geometric features specific to the pathology being treated.

[0024] The bone plate can for example be generated from a digital model of the patient's bone.

[0025] The bone plate is obtained by additive manufacturing.

[0026] In the case of a personalized plate, additive manufacturing is currently more suitable than subtractive manufacturing: the production speed and therefore the machine cost associated with the manufacture of unique parts is much lower for additive manufacturing with SLM (Selective Laser Melting) or SEBM (Selective Electron Beam Melting) technologies. Indeed, it is possible to print a set of personalized parts, with variable designs, in a single production run.

[0027] The plate is made of a biocompatible metallic material such as titanium or steel alloys.

[0028] The bone plate 2 extends between a so-called lower surface 21 and a so-called upper surface 22. A portion of the lower surface 21 is intended to be turned towards the bone. It may or may not be in contact with the bone.

[0029] Additive manufacturing of the plate allows geometric and mechanical optimization respectively of the plate and the bone / implant / screw assembly.

[0030] It also allows a design avoiding the preoperative fretwork step, necessary to adapt the plate to the anatomy and treatment of the patient's pathology. This step leads to a plasticization of the plate, detrimental to its mechanical behavior.

[0031] The bone plate has a plate hole 23 passing through the plate.

[0032] In the example shown, a counterbore 24, called upper, of the plate hole is made on the upper side of the plate.

[0033] Still in the example shown, a counterbore 25, called lower, of the plate hole is made on the lower side of the plate.

[0034] The plate may have several holes, including at least hole 23, but also other holes having different functions, for example compression holes or oblong holes, etc.

[0035] The insert 3 is of generally cylindrical conformation and comprises a central threaded through hole 34 cooperating with a thread of the bone anchoring device 4.

[0036] Advantageously, the insert is formed from a metallic material, preferably medical grade, such as stainless steel, titanium, steel alloy, titanium alloy.

[0037] The composition of the fixing elements must meet the requirements of biocompatibility within a living organism. Materials of heterogeneous composition can in fact generate, through tribology or corrosion, degradation products that are toxic to cells. It is therefore recommended to have fixing elements of an identical nature and chemical composition.

[0038] The central tapped hole 34 may include a frustoconical portion providing a seat for a frustoconical head of a bone anchor.

[0039] The truncated cone shape of the tapping has advantages: the size is smaller, the centering and positioning of the screw is easier, the mechanical strength is better, the screw is locked with fewer rotations.

[0040] The insert comprises a shoulder 33 and elastic fitting means 32 cooperating with the plate hole to be embedded therein, said insert being manufactured by subtractive manufacturing.

[0041] In the example shown, the insert has an axial dimension substantially equal to that of the hole 23 of the bone plate 2. As can be seen in [Fig. 2], in the example shown, the shoulder 33 is arranged on the side of the upper surface 22 of the bone plate 2 when the insert is embedded in the bone plate 2.

[0042] Still in the example shown, the elastic fitting means 32 are formed by fins 321 comprising external projections 322.

[0043] In the example shown in [Fig.3], there are 4 tabs, diametrically opposed two by two.

[0044] As shown in [Fig.3], the insert has a flank comprising a flat 36.

[0045] The insert is preferably manufactured by subtractive manufacturing for achievable geometric tolerances and low production costs on parts produced in large series.

[0046] Anchoring device

[0047] The bone anchoring device 4 has a thread 43 cooperating with the central tapped hole 34 of the insert 3.

[0048] Preferably, the anchoring device has another thread 44, spaced from the thread 43, this other thread being provided for anchoring the device within bone tissue.

[0049] Typically, this anchoring device is a screw, made of metallic material, preferably medical grade, such as stainless steel, titanium, steel alloy, titanium alloy, preferably corresponding to the material of the plate and the insert.

[0050] Operation

[0051] The insert 3 can be fitted into the hole in the bone plate.

[0052] The term elastic fitting is intended to define the locking operations of two parts which translate relative to each other until a projecting part of the first part engages in a housing of corresponding shape of the second part by an elastic return effect in a direction perpendicular to the translation, and so that, once the projecting part is in the corresponding housing, the correspondence of shape tends to oppose a translation movement in an opposite direction. The elastic fitting can be made irreversible.

[0053] When the bone anchoring device 4 is aimed into the insert 3, the head of the bone anchoring device comes into contact with the threaded surface of the insert, which causes the sectors of the upper section of the insert 3 to spread apart and to be pressed against the walls of the through plate hole 23.

[0054] The flat 36 cooperates with a bearing surface 26 of the bone plate 2 to prevent any rotation of the insert in the hole 23 of the bone plate 1.

[0055] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In addition, the various characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other.

Claims

Claims

1. Insert (3) for a bone plate (2) having a through plate hole (23), said insert comprising a central through-threaded hole (34) which comprises a frustoconical-shaped portion providing a seat for a frustoconical head of a bone anchor, the central hole being provided to cooperate with a thread (43) of a bone anchor device (4), said insert further comprising a shoulder (33) and elastic fitting means (32) cooperating with the plate hole to be embedded therein, said insert being manufactured by subtractive manufacturing.

2. A support assembly (1) comprising: - a bone plate (2) having a through plate hole, - an insert (3) according to the preceding claim, in which the insert is embedded in the bone plate hole by elastic fitting, said bone plate being manufactured by additive manufacturing and said insert being manufactured by subtractive manufacturing.

3. Assembly according to the preceding claim, in which said insert (3) has a flank comprising a flat cooperating with a bearing surface of the bone plate (2).

4. A support assembly according to one of the two preceding claims, further comprising a bone anchoring device (4) having a thread (43) cooperating with the central threaded through hole (34).

5. An assembly according to the preceding claim, wherein the bone anchoring device (4) further comprises another thread (44) spaced from the thread (43), said other thread being provided for anchoring the device within bone tissue.

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