Implantable artificial ligament, and process for manufacturing such an artificial ligament

Abstract

The present invention relates to an artificial ligament (10) comprising an elongate braided hollow sheath (20) having an inner volume and a deformable insert (30) accommodated in the inner volume over at least part of the length of the sheath. The insert is elastic, thus delaying the rigid deformation phase of the artificial ligament (10) when a longitudinal tensile force is applied thereto.

Description

[0001] Implantable artificial ligament, and method of manufacturing such an artificial ligament

[0002] Technical Field

[0003] The present invention relates to the technical field of implantable artificial ligaments, in particular for the prevention and / or treatment of a pathology of the spine, more particularly for the prevention and / or treatment of pathology(ies) occurring following a fusion of one or more vertebrae of the spine, preferably for the prevention and / or treatment of proximal junctional kyphosis (PJK).

[0004] The present invention also relates to the technical field of methods for manufacturing such artificial ligaments.

[0005] Prior art

[0006] After spinal surgery to fuse one or more vertebrae, spinal deformations during patient movements, particularly flexion, are distributed across the remaining unfused vertebrae, which are therefore located near the fused spinal area. This arrangement concentrates the loads on the unfused vertebrae and thus modifies the natural load distribution gradient observed in a spine without a fused area. Naturally, the facet joints block posterior migrations of the spine and the intervertebral discs block anterior migrations of the spine. In addition, these elements of the spine include joint capsules containing synovial fluid that acts as a lubricant for the facets to prevent bone wear of the joints. Following fusion of vertebra(s), the facet joints near the fused area no longer function properly.The loads are thus transferred to the ligaments, which are not naturally configured to accept such a high accumulation of loads. The imbalances created on the spine thus cause kyphosis, or even spondylolisthesis in the most serious cases.

[0007] Proximal junction kyphosis (PJK) can lead to proximal junction failure (PJF), which is a serious early complication of adult spinal surgery and may require revision surgery. Risk factors for spinal surgery include overcorrection, undercorrection, excessive ligament dissection, and osteoporosis. These spinal pathologies (PJK, PJF) typically occur within three months of spinal surgery in approximately 66% of cases. Up to 40% of adult spinal surgery patients experience PJK. Progression from PJK to PJF should be avoided, as PJF requires revision surgery, which poses additional discomfort and risks to the patient, and incurs additional costs.

[0008] Following a spinal fusion(s), we seek to recreate a natural load distribution gradient and relieve the non-fused vertebrae, in particular to avoid an anterior collapse of the fused area.

[0009] It is known to use braided textile ligaments to eliminate the abrupt transition between thoracic rigidity after fusion of vertebrae, particularly lumbar vertebrae, and the flexibility of non-fused vertebral segments. However, the proposed textile ligaments have a very rigid and insufficiently elastic behavior. These ligaments do not adapt correctly to the transition between the rigidified fused area and the adjacent non-fused areas.

[0010] There is thus a need for an artificial ligament that has rigid behavior in certain deformation ranges and elastic behavior in other deformation ranges in order to compensate for thoracic rigidity compared to the flexibility of unfused vertebral segments.

[0011] Statement of the invention

[0012] The subject of the present invention, according to a first aspect, is an artificial ligament, in particular for the treatment of proximal junctional kyphosis (PJK), overcoming all or part of the aforementioned problems in that it comprises, advantageously consists essentially of, even more advantageously consists of, an elongated hollow braided sheath having an interior volume, and a deformable insert housed in the interior volume of the hollow braided sheath and this over at least part of the length of said hollow sheath.

[0013] Advantageously, the artificial ligament has:

[0014] - a deformation phase A in which the director coefficient ka measured on a curve Ca of traction force (N) - elongation (%) of said artificial ligament is less than or equal to 6 Newtons / %, advantageously less than or equal to 5 Newtons / %; and

[0015] - a deformation phase B in which the director coefficient kb measured on said curve Q a tensile force (N) - elongation (%) of said artificial ligament is greater than or equal to 4 Newtons / %, advantageously greater than or equal to 5 Newtons / %, and less than or equal to 40 Newtons / %, the elongation of said artificial ligament in said deformation phase B is greater than or equal to 2% and less than or equal to 15%, in particular less than or equal to 10%;

[0016] - a deformation phase C in which the director coefficient kc measured on said curve Ci atensile force (N) - elongation (%) of said artificial ligament is greater than the director coefficient kb of phase B.

[0017] Advantageously, the arrangement of a deformable insert over all or part of the length of the internal volume of the hollow sheath makes it possible to modify the mechanical behavior of said sheath. In particular, this deformable, elastic insert makes it possible to increase the capacity of the sheath, and therefore of the ligament ultimately, to elongate and to create a range of rigidity, particularly suitable for the treatment of CJP.

[0018] Advantageously, in phase A, corresponding to low deformations, in particular to an elongation (%) less than or equal to 5% or 2%, we observe a low elongation under a low load of the artificial ligament then an elongation which increases slightly for a significant load.

[0019] A non-exhaustive, non-limiting technical explanation of the present invention is that in phase A, the behavior of the artificial ligament is dominated and therefore largely attributable to the deformable insert. Then in phase B, the threads of the hollow textile sheath continue to slide relative to each other and thus compress the deformable insert, the applied force and the elongation obtained increase. Finally, in the last phase, namely phase C, the deformable insert is completely compressed / crushed by the threads of the hollow sheath, and the behavior of the artificial ligament is imparted by said threads of the hollow sheath. The behavior in phase C corresponds to the so-called rigid behavior phase of the artificial ligament.

[0020] The deformable insert thus makes it possible to shift the rigid behavior of the hollow sheath at significant elongations, and to maintain a flexible / elastic behavior at low, or even very low, elongations. This arrangement makes it possible to attribute flexibility to the levels of the unfused vertebrae arranged near those which are fused for low amplitude movements, and rigidity for greater movements.

[0021] Advantageously, the artificial ligament is implantable, in particular it is suitable for being inserted into a living organism (human or animal) for a prolonged period, for example from a few days to several months or years.

[0022] In one embodiment, the Q curve atensile force - elongation of said artificial ligament is measured on a Llyod Lrx Plus machine, with a tensile speed of 100 mm / minute, in particular at room temperature, for example at a temperature ranging from 19°C to 23°C, in particular without any particular relative humidity condition, possibly a pretension of IN to ION is applied, in particular at a preload speed of 50 mm / min. The artificial ligament comprises in particular first and second ends, a first end is arranged in first jaws, and a second end is arranged in the second jaws, the first jaws are fixed while the second jaws move in translation at a speed of 100 mm / minute.

[0023] Preferably, the initial test length of the artificial ligament is 395 mm + / - 5 mm. Preferably, the load sensor is 5000N.

[0024] In particular, the Llyod Lrx Plus machine is a single-column testing machine, more particularly available in the Plus / Easy Test series of the Llyod Instruments Materials testing range marketed by the company AMETEK. Preferably with a standard RS232 computer interface. Preferably, the force sensor has the reference XLC- 5000-A1, with an accuracy of 0.5% up to 5000N, in particular the model 01 / 2364. In one embodiment, the deformable insert is elastic.

[0025] The tensile force applied to said insert or ligament or to said braided hollow sheath is always considered in this text as applied in the longitudinal direction of said insert or ligament or braided hollow sheath.

[0026] Preferably, the values ​​of elongation (%) and tensile force measured and indicated in this text on the Q curve atensile force (N) - elongation (%) of said artificial ligament are obtained during the first tensile cycle, i.e. after the first traction, carried out on the artificial ligament after removal from its sterilized packaging. Preferably, the tensile forces and elongation (%) indicated in this text are not tensile forces causing rupture, and therefore elongations at rupture, of the ligament, unless otherwise specified.

[0027] In the present text, the term elastic insert means an insert having a residual deformation less than or equal to 10% for a longitudinal applied force less than or equal to 300 N, preferably less than or equal to 200 N, more preferably less than or equal to 100 N. The elastic insert thus deforms longitudinally under an applied force of 300 N at most and recovers its initial undeformed length or with only a variation of 10% at most, advantageously of 8% at most, even more advantageously of 5% at most, in particular of 3% at most. The deformation can be calculated as follows: (Residual length of the deformable insert after at least one longitudinal deformation - Initial length of the deformable insert having not undergone any longitudinal deformation) / Initial length of the deformable insert having not undergone any longitudinal deformation. Artificial ligament

[0028] Preferably, the artificial ligament comprises first and second ends, in particular free ends, still preferably between which the longitudinal body of said artificial ligament extends. Preferably, the artificial ligament comprises a length L, and a width I (if it is flat) or a diameter d (if it is substantially round).

[0029] Preferably, the length L of the artificial ligament is greater than or equal to 50 mm and less than or equal to 400 mm, more preferably greater than or equal to 100 mm and less than or equal to 300 mm.

[0030] Preferably, the width I or the diameter d of the artificial ligament is greater than or equal to 3 mm and less than or equal to 20 mm, more preferably less than or equal to 15 mm, preferably less than or equal to 10 mm.

[0031] Preferably, the artificial ligament has a longitudinal axis L| a, advantageously extending between its first and second ends, in particular free ends.

[0032] Preferably, the artificial ligament has a transverse axis T| a substantially secant to the L axis| a , in particular substantially perpendicular to the L axis| a .

[0033] The artificial ligament can be elongated and flat or elongated and substantially round.

[0034] Preferably, the elongation at break of the artificial ligament is less than or equal to 50%, in particular less than or equal to 40%, more particularly greater than or equal to 10% or 20%. More preferably, the braided hollow sheath then comprises polyethylene terephthalate threads.

[0035] Hollow sheath

[0036] Preferably, the hollow sheath comprises first and second ends, more preferably between which the longitudinal body of the hollow sheath extends.

[0037] Preferably, the hollow sheath has a length L gc and a width l gc (if it is flat) or a diameter of gc (if it is noticeably round).

[0038] Preferably, the length L gc of the hollow sheath is greater than or equal to 50 mm and less than or equal to 400 mm, more preferably greater than or equal to 100 mm and less than or equal to 300 mm.

[0039] Preferably, the width l gc or the diameter of gc of the hollow sheath is greater than or equal to 3 mm and less than or equal to 20 mm, more preferably less than or equal to 15 mm, preferably less than or equal to 10 mm.

[0040] Preferably, the hollow sheath has a longitudinal axis L gc and transverse axis T gc , in particular substantially perpendicular to the L axis gc .

[0041] The hollow sheath can be elongated and flat or elongated and substantially round. The hollow sheath is braided and consists of several braided wires.

[0042] Preferably, the hollow sheath comprises, advantageously consists essentially of, even more advantageously consists of, one or more monofilament yarn(s), and / or one or more spun fiber yarn(s), and / or one or more multifilament yarn(s), preferably one or more multifilament yarn(s).

[0043] The hollow sheath comprises an interior volume, in particular delimited by its internal wall, substantially opposite its external wall. Said interior volume receiving over all or part of its length L gc said insert.

[0044] The hollow sheath comprises, advantageously consists essentially of, even more advantageously consists of, at least one thread or several threads which is / are totally, or only partially, bioresorbable, or non-resorbable, preferably non-resorbable.

[0045] Preferably, the braided hollow sheath comprises, advantageously consists essentially of, even more advantageously consists of, several braided strands, in particular a braided strand is supported by a spindle on the braiding machine, each braided strand comprising one or more thread(s), in particular as described in the present text.

[0046] Preferably, the braided hollow sheath comprises, advantageously consists essentially of, even more advantageously consists of, a number of braided strands ranging from 8 to 64, still preferably ranging from 12 to 52 strands, preferentially comprises from 16 strands to 48 strands.

[0047] Preferably, the hollow sheath, in particular braided, comprises, advantageously is essentially made up of, even more advantageously is made up of, one or more threads comprising at least one material chosen from the list comprising: polyethylene terephthalate, high tenacity polyethylene terephthalate, polybutylene terephthalate, high molecular weight polyethylene, very high molecular weight polyethylene, polyamide 4-6 or 6-6,... or a mixture of these, preferably from the list comprising: polyethylene terephthalate, in particular high tenacity, high or very high molecular weight polyethylene (e.g. HMWPE or UHMWPE).

[0048] In this text, bioresorbable is understood to mean the capacity of a material (for example a textile, a thread, a foam, or a coating, etc.) to be degraded by a living organism in which it is implanted so as to disappear after a given period, for example after 10 days or after several months, for example after 6 months. Deformable insert

[0049] Preferably, the insert comprises first and second ends, more preferably between which the longitudinal body of the insert extends.

[0050] The insert may be continuous or discontinuous. When the insert is discontinuous, the insert comprises several insert sections arranged adjacently or spaced apart within the interior volume of the hollow sheath.

[0051] Preferably, the insert has a length L, and a width I, (if it is flat) or a diameter d, (if it is substantially round).

[0052] Preferably, the length L of the insert is greater than or equal to 50 mm and less than or equal to 400 mm, more preferably greater than or equal to 100 mm and less than or equal to 300 mm.

[0053] Preferably, the width I, or the diameter d, of the hollow sheath is greater than or equal to 3 mm and less than or equal to 20 mm, more preferably less than or equal to 15 mm, preferably less than or equal to 10 mm.

[0054] Preferably, L, is less than or equal to L gc .

[0055] Preferably, I, or d, is less than or equal to l gc or d gc .

[0056] Preferably, the insert has a longitudinal axis L, and a transverse axis T,, in particular substantially perpendicular to the axis L,.

[0057] The insert can be elongated and flat or elongated and substantially round.

[0058] The insert is preferably not a braid.

[0059] Preferably, the insert is not fibrous (i.e. does not comprise thread(s) and / or fibres). Preferably, the insert comprises one or more elastomeric material(s).

[0060] In this text, the term elastomeric material is understood to mean any material having an elongation at break greater than or equal to 200% or 300% or 400%, preferably greater than or equal to 500%, for example measured with the ISO 37:2017 standard entitled Vulcanized or thermoplastic rubber, Determination of tensile stress and strain properties.

[0061] Preferably, the insert comprises (in particular is) an elongated element comprising one or more threads, and / or one or more foam polymer cord(s), and / or one or more rod(s), and / or one or more extruded polymer profile(s), and / or one or more woven and / or knitted textile strip(s) / cord(s), and / or one or more non-woven strip(s) / cord(s).

[0062] Preferably, the insert comprises (in particular is) one or more polymer rod(s) (in particular substantially cylindrical, in particular solid and / or hollow) and / or one or more extruded polymer profile(s) (in particular multi-lobed and / or star-shaped and / or spring-shaped), in particular comprising one or more elastomer(s).

[0063] A hollow rod is advantageously a tube.

[0064] The insert is preferably a rod or a set of several rods, in particular having (in particular each) a substantially cylindrical cross-section. When the insert is a set of several rods, said rods are arranged parallel to each other.

[0065] Preferably, said at least one rod, or each of said rods, and / or said at least one extruded polymer profile, or each of said extruded polymer profiles, comprises, advantageously consists essentially of, even more advantageously consists of, one or more material(s) chosen from: polyurethane, polycarbonate-urethane, or polydimethyl siloxane, or a mixture of these.

[0066] Preferably, said material(s) chosen from: polyurethane, polycarbonate-urethane, or polydimethyl siloxane, or a mixture of the latter, is / are one or more elastomers.

[0067] Preferably, said elastomer(s) each have a Shore A hardness greater than or equal to 20 and less than or equal to 90, more preferably greater than or equal to 50 and less than or equal to 80, in particular greater than or equal to 70 and less than or equal to 80.

[0068] Shore A hardness can be measured using ISO 48-4:2018, Vulcanized or thermoplastic rubber, Determination of hardness, Part 4: Indentation hardness by the durometer method.

[0069] In one embodiment, the polycarbonate-urethane (PCU) has a Shore A hardness greater than or equal to 80 and less than or equal to 90. In a preferred example, the polycarbonate-urethane is chosen from those marketed by the company DSM under the brand Bionate®.

[0070] In one embodiment, the polydimethylsiloxane is an elastomer, more preferably has a Shore A hardness greater than or equal to 20 and less than or equal to 80. In a preferred example, the polydimethylsiloxane is marketed by the company Nusil.

[0071] In one embodiment, the deformable insert does not occupy the entire interior volume of the hollow sheath.

[0072] In one embodiment, the hollow sheath comprises an interior volume Vint, and the full volume occupied by the deformable insert represents at most 95%, preferably at most 90%, more preferably at most 85%, preferentially at most 80%, in particular at most 75%, more particularly at most 70%, of the interior volume Vint of the hollow sheath. The term full volume of the deformable insert is understood to mean any volume occupied by the deformable insert not comprising a void, for example not comprising the orifices of a foam of the deformable insert (i.e. all the full material).

[0073] Preferably, the volume Vint of the hollow sheath is calculated theoretically based on the dimensions (mm) of the hollow sheath (internal diameter or internal width and internal height, internal length).

[0074] In one embodiment, the hollow sheath comprises an interior volume Vint, and the full volume occupied by the deformable insert represents at least 25%, preferably at least 35%, more preferably at least 45%, preferentially at least 55%, in particular at least 65%, more particularly at least 75%, of the interior volume Vint of the hollow sheath.

[0075] Advantageously, since the interior volume is not filled by the deformable insert, there remain voids in the interior volume which will be compressed during a longitudinal deformation of the ligament, thus making it possible to delay the engagement of the hollow sheath in the longitudinal deformation and to stress the insert first.

[0076] The deformable insert may be totally or partially bioresorbable, or non-resorbable, preferably non-resorbable.

[0077] In a first embodiment, the deformable insert and / or the braided sheath each comprises (advantageously is / are each essentially made up of, even more advantageously is / are each made up of) one or more threads, preferably multifilament, made of high or very high molecular weight polyethylene (in particular very high molecular weight or in English UHMWPE), and / or having at least one of the following characteristics:

[0078] - a linear density (dtex) greater than or equal to 200 dtex, preferably greater than or equal to 200 dtex and less than or equal to 600 dtex, in particular greater than or equal to 300 dtex and less than or equal to 550 dtex, more particularly greater than or equal to 400 dtex and less than or equal to 500 dtex; and / or

[0079] - a tenacity (cN / dtex) greater than or equal to 25 cN / dtex, preferably greater than or equal to 25 cN / dtex and less than or equal to 50 cN / dtex, in particular greater than or equal to 30 cN / dtex and less than or equal to 45 cN / dtex, more particularly greater than or equal to 30 cN / dtex and less than or equal to 40 cN / dtex; and / or

[0080] - an elongation at break of less than or equal to 30%, preferably less than or equal to 20%, more preferably less than or equal to 10%, preferably less than or equal to 5%; and / or - a breaking force greater than or equal to 80 N, preferably greater than or equal to 100 N, more preferably greater than or equal to 140 N, preferably greater than or equal to 160 N, in particular less than or equal to 1000 N.

[0081] In a second embodiment, possibly in combination with the first embodiment, the deformable insert and / or the braided sheath comprises / comprise (each) (advantageously is / are each consisting essentially of, even more advantageously is / are each consisting essentially of) one or more threads, preferably multifilament, made of polyethylene terephthalate, and / or having at least one of the following characteristics:

[0082] - a linear density (dtex) greater than or equal to 25 dtex, preferably greater than or equal to 25 dtex and less than or equal to 150 dtex, in particular greater than or equal to 25 dtex and less than or equal to 100 dtex, more particularly greater than or equal to 25 dtex and less than or equal to 65 dtex; and / or

[0083] - a tenacity (cN / dtex) greater than or equal to 2.5 cN / dtex, preferably greater than or equal to 2.5 cN / dtex and less than or equal to 10.0 cN / dtex, in particular greater than or equal to 4.0 cN / dtex and less than or equal to 9.0 cN / dtex, more particularly greater than or equal to 6.0 cN / dtex and less than or equal to 9.0 cN / dtex; and / or

[0084] - an elongation at break of less than or equal to 50%, preferably less than or equal to 40%, more preferably less than or equal to 30%, preferably less than or equal to 20%; and / or

[0085] - a breaking force greater than or equal to 150 cN, preferably greater than or equal to 250 cN, more preferably greater than or equal to 300 cN, in particular less than or equal to 1000 cN.

[0086] Preferably, the linear density is measured using the EN 13392 standard, in particular dating from 2001 when it is a monofilament yarn, or according to the EN ISO 2060 standard dating from 1995 when it is a multifilament yarn.

[0087] Preferably, elongation at break, tenacity and breaking force are measured using the EN 13895 standard, in particular dating from 2003 when it is a monofilament yarn, or according to the EN ISO 2062 standard dating from 1993 when it is a multifilament yarn.

[0088] In one embodiment, the braided hollow sheath comprises one or more polyethylene terephthalate yarns, in particular high tenacity yarns, the mass fraction of which in said sheath is greater than 0% and less than or equal to 50% or 40% or 30% or 20% or In one embodiment, the braided hollow sheath comprises one or more polyethylene yarns, in particular high or very high molecular weight yarns, the mass fraction of which in said hollow sheath is greater than or equal to 50% or 60% or 70% or 80% or 90%.

[0089] In one embodiment, the braided hollow sheath comprises one or more polyethylene threads, in particular of high or very high molecular weight, and one or more polyethylene terephthalate threads, in particular of high tenacity, the mass fraction (F PE ) in polyethylene thread(s) is greater than the mass fraction (F PEr) in polyethylene terephthalate yarn(s) in the hollow sheath, in particular the ratio between the mass fractions F PE : F Pet varies from 90:10 to 60:40.

[0090] Advantageously, polyethylene is more resistant to abrasion than polyethylene terephthalate because the coefficient of friction of polyethylene is lower than that of polyethylene terephthalate. The presence of a large quantity of polyethylene makes it possible to improve the longevity of the artificial ligament which is worn when it is put under tension on the arthrodesis rods fixed to the vertebrae.

[0091] Preferably, the insert is elongated, more preferably the length of the insert is substantially equal to the length of the braided hollow sheath.

[0092] Preferably, the insert and the braided hollow sheath have respective central longitudinal axes L in and L gc confused.

[0093] Preferably, the deformable insert and the braided hollow sheath are coaxial.

[0094] Preferably, the deformation phases take place in this order, A, then B and finally C, the forces and elongations being increasing from phase A to phase B then phase C.

[0095] Preferably, phases A, B and C are distinct from each other.

[0096] Preferably, the artificial ligament exhibits deformation phases A, then B and finally C under the application of an increasing force (N).

[0097] Preferably, the curve C| a is the LAI 1 curve, or LAI 2, or LAI3, or LAI 4 or LAI5, in particular represented in figures 8 and 9.

[0098] The slope coefficient (ka) is understood to be the slope coefficient of a straight line TA tangent at any point on the curve C in phase A, preferably at any point on the curve C| awhose elongation is less than or equal to 7% or 5% or 2%.

[0099] The slope coefficient (kb) is understood to be the slope coefficient of a straight line TB tangent at any point on the curve C| a in phase B, preferably at any point on the Q curve a whose elongation is greater than or equal to 5% or 2%, preferably less than or equal to 15%, preferably less than or equal to 10% or 9% or 8% or 7% or 4%.

[0100] The direction coefficient (kc) is understood to mean the direction coefficient of a tangent TC line at any point on curve C in phase C, preferably at any point on curve C whose elongation is greater than or equal to 4% or 5%, preferably greater than or equal to 6% or 7%, still preferably greater than or equal to 10%, possibly greater than or equal to 15%.

[0101] Preferably, the slope coefficient (kc) is the slope coefficient of a tangent TC line at any point of curve C in phase C at any point of curve C whose elongation is less than or equal to 30% or 20%.

[0102] By "is essentially made up of" we mean that the element(s) introduced by this expression is / are present in the majority, possibly at 95% by mass, it is possible that other element(s) (not described) is / are present but it is (are not) in the majority.

[0103] In an alternative embodiment, the deformable insert is a rod comprising a thermoplastic or thermosetting elastomer, preferably comprising (advantageously consisting essentially of, even more advantageously consisting of) one or more polymer(s) chosen from: a polyurethane, a polycarbonate-urethane, a polydimethylsiloxane, or a mixture of these.

[0104] In this text, thermoplastic elastomer is understood to mean that said elastomer present in the insert can be transformed by heating it (in particular molded, extruded or injected), in particular said elastomer has a softening or melting temperature allowing it to be shaped when hot.

[0105] In this text, thermosetting elastomer is understood to mean that said elastomer present in the insert cannot be transformed by heating it, in particular said elastomer has no melting temperature.

[0106] In an alternative embodiment, the insert is a rod or a set of rod(s), and each rod is essentially made up of, in particular is made up of, one or more polymer(s) chosen from the following polymers, in particular the following elastomers: polyurethane, polycarbonate-urethane, polydimethylsiloxane or a mixture thereof.

[0107] In particular, said polymer is a polyurethane or a polycarbonate-urethane or a polydimethylsiloxane. In an alternative embodiment, said insert is a rod or a set of rod(s), in particular said rod or each of said rods is extruded.

[0108] In a variant, the cross-section of said rod or of each of said rod(s) has as its largest dimension (d), or as its diameter (d) when the cross-section is substantially circular, d being greater than or equal to 1 mm and less than or equal to 5 mm.

[0109] In an alternative embodiment, said artificial ligament has an elongation less than or equal to 15%, possibly less than or equal to 10%, under the effect of a tensile force of the order of 250 Newtons or 200 Newtons, preferably after at least 10 traction cycles, each traction cycle comprising the application of a tensile force of the order of 250 Newtons or 200 Newtons.

[0110] In an alternative embodiment, the difference (%) between the residual elongation (%) obtained after a traction cycle (n) of the ligament and the residual elongation (%) obtained after a traction cycle (n+1) of the ligament, with n being an integer other than 0, preferably n being equal to 10, is less than or equal to 15%, preferably less than or equal to 10%, more preferably less than or equal to 8%, preferably less than or equal to 5%, even more preferably less than or equal to 3%, each traction cycle comprising the application of a traction force of the order of 250 Newtons or 200 Newtons.

[0111] The tensile force of the order of 250 Newtons or 200 Newtons is less than the tensile force of rupture of the artificial ligament.

[0112] The integer n corresponds to the number of traction cycles.

[0113] A traction cycle in this text includes the application of the traction force, here of the order of 250 N or 200 N, then the return to the resting state of the ligament, i.e. without exerting any traction force on the ligament.

[0114] In this text, residual elongation (%) is understood to mean the difference between the residual length (mm) of the artificial ligament after a traction cycle (n) and the initial length (mm) of the artificial ligament (advantageously before the application of any traction cycle) divided by the initial length (mm) of the artificial ligament ((residual length of the ligament - initial length of the ligament) / initial length of the ligament).

[0115] In an alternative embodiment, in deformation phase A, the elongation of said artificial ligament is less than or equal to 7% or 5%, possibly less than or equal to 2%, under the application of a tensile force less than or equal to 200 Newtons; and in deformation phase C, the elongation of said artificial ligament is greater than or equal to 5%, preferably greater than or equal to 10%, more preferably greater than or equal to 15%, preferentially less than or equal to 30%, under the application of a tensile force greater than or equal to 200 Newtons and less than or equal to 800 Newtons.

[0116] In an alternative embodiment, in particular in deformation phase A, the elongation of said artificial ligament is less than or equal to 5%, possibly less than or equal to 2%, under the application of a tensile force less than or equal to 150 Newtons, preferably less than or equal to 100 Newtons, still preferably less than or equal to 50 Newtons, preferentially less than or equal to 40 Newtons or 30 Newtons or 20 Newtons or 15 Newtons or 10 Newtons.

[0117] Advantageously, in phase A of deformation, the elongation of said artificial ligament is less than or equal to 5%, possibly 2%, under the application of a tensile force greater than 0 Newtons, advantageously greater than or equal to 5 Newtons or 10 Newtons.

[0118] In an alternative embodiment, in particular in deformation phase C, the elongation of said artificial ligament is greater than or equal to 5%, advantageously greater than or equal to 10%, even more advantageously greater than or equal to 15%, in particular less than or equal to 50% or 40%, under the application of a tensile force greater than or equal to 200 or 300 Newtons, in particular less than or equal to 300 Newtons or 250 Newtons.

[0119] In an alternative embodiment, in particular in phase A, the elongation of the artificial ligament is less than or equal to 6% or 5% or 4% or 2%, under the application of a tensile force less than or equal to 50 Newtons, preferably less than or equal to 40 or 30 or 20 or 15 or 10 Newtons (in particular greater than ON).

[0120] In an alternative embodiment, in particular in phase B, the elongation of the artificial ligament is greater than or equal to 2% or 5% or 7%, preferably less than or equal to 10% or 9% or 8% or 7% or 4%, under the application of a tensile force greater than or equal to 10 or 20 or 30 or 40 or 50 Newtons, preferably less than or equal to 100 or 70 or 60 or 50 Newtons.

[0121] In an alternative embodiment, in particular in phase C, the elongation of the artificial ligament is greater than or equal to 4% or 5% or 6% or 7% or 8%, preferably less than or equal to 15% or 10%, under the application of a tensile force greater than or equal to 100N or 150N or 200N or 250N, preferably less than or equal to 400N or 350N or 300N or 250N or 200N or 150N.

[0122] In an alternative embodiment, kb is greater than ka, in particular kb is greater than or equal to twice ka, more particularly kb is greater than or equal to three times ka. The foot of the curve is very important when moving from phase A to phase B because the force applied in phase A for very low elongations (of the order of a few %) is close to 0 Newtons.

[0123] In an alternative embodiment, kc is greater than kb, in particular kc is greater than or equal to twice kb, more particularly kc is greater than or equal to three times kb, even more particularly kc is greater than or equal to four times kb.

[0124] An increase in stiffness is observed in phase C of deformation of the artificial ligament, in which mainly the mechanical properties of the sheath threads are expressed. The curve base is very important during the transition from phase B to phase C.

[0125] In an alternative embodiment, in deformation phase B, the tensile force applied to the artificial ligament is less than or equal to 200 Newtons, preferably less than or equal to 100 Newtons.

[0126] In an alternative embodiment, the interior volume of said at least one part of the hollow braided sheath receiving said insert comprises one or more compressible empty cavities so as to collapse during the transition from deformation phase A to deformation phase B.

[0127] Advantageously, the empty cavities are reversibly compressible so that when passing from phase B to phase A, and possibly at rest, said cavities recover their initial volumes.

[0128] The said cavity(ies) may each have a dimension of the order of a micrometer or a millimeter.

[0129] In an alternative embodiment, the insert has a rate of empty cavities greater than or equal to 30%, preferably less than or equal to 90%, still preferably less than or equal to 80%, preferably less than or equal to 70%.

[0130] The void ratio of the insert is preferably calculated with the following formula: 100x[l(P / (MxS))] in which P is the linear mass of the insert in grams / cm, M is the density of the material forming the insert in grams / cm 3 (e.g. of the polymer material from which the insert is formed), and S is the cross-sectional area of ​​the insert in cm 2 .

[0131] In an alternative embodiment, the full surface area of ​​the cross-section of the insert is less than the total surface area (mm 2) of the cross-section of said at least one part of the braided hollow sheath receiving said insert in its interior volume. Advantageously, the artificial ligament comprises empty spaces capable of being crushed during its progressive elongation under the application of a longitudinal tensile force.

[0132] In an alternative embodiment, the insert is chosen from: a tube, a foam cord, a deformable profile, and at least one elongated multi-lobed element, in particular tri-lobed or quadri-lobed, for example at least one multi-lobed monofilament.

[0133] Advantageously, the insert has an irregular structure capable of creating cavities and / or comprises a foamed material comprising cavities.

[0134] Preferably, the deformable profile is a spring profile.

[0135] In one variant, the insert is chosen from: a tube, a foam, and at least one elongated element, in particular at least one rod or at least one monofilament thread, more particularly multi-lobed.

[0136] In one variant, the insert is a solid or hollow cylindrical polymer rod or a multi-lobed or spring-loaded extruded polymer profile, in particular tri-lobed or quadri-lobed.

[0137] Preferably, the tube has an internal diameter greater than or equal to 0.50 mm, or 0.75 mm, and less than or equal to 3 mm, preferably less than or equal to 2.5 mm or 2 mm or 1.5 mm. Preferably, the tube has an external diameter greater than or equal to 0.50 mm, or 0.75 mm, and less than or equal to 3 mm, preferably less than or equal to 2.50 mm or 2 mm or 1.5 mm.

[0138] Preferably, the thickness of the wall of the tube is greater than or equal to 0.10 mm, preferably greater than or equal to 0.20 mm, more preferably less than or equal to 1 mm, preferably less than or equal to 0.50 mm or 0.40 mm or 0.30 mm, for example approximately 0.25 mm to within + / - 0.05 mm.

[0139] Preferably, the cylindrical or multi-lobed rod has a diameter greater than or equal to 1 mm, and less than or equal to 5 mm or 4 mm or 3 mm, for example approximately 2 mm to within + / - 0.5 mm. In an exemplary embodiment, the insert is a hollow cylindrical rod, i.e. a tube, comprising polyurethane having a Shore D hardness ranging from 50 to 75, in particular 65 Shore D to within + / - 5, for example of the Tecothane® brand marketed by Lubrizol.

[0140] In an alternative embodiment, the deformable insert has an elongation greater than or equal to 200% or 300%, and less than or equal to 500% or 400%, in particular for a tensile force greater than or equal to 10N and less than or equal to 100N, in particular less than or equal to 60N or 50N, or for a deformation stress greater than or equal to 100MPa and less than or equal to 150MPa or 100 MPa. In an alternative embodiment, the insert is an elongated element extruded, foamed or printed in three dimensions, in particular by additive or subtractive manufacturing or a combination thereof.

[0141] In an alternative embodiment, said insert comprises at least one polymer material having a Shore A hardness ranging from 5 to 90, in particular ranging from 5 to 50 or from 50 to 80, more particularly ranging from 20 to 50.

[0142] Preferably, Shore A hardness is determined using the NF EN ISO 868 standard dating from 2003.

[0143] Preferably, said insert has a Shore A hardness ranging from 5 to 90, in particular from 5 to 50, more particularly from 20 to 50.

[0144] Preferably, at least 50% by mass of said insert consists essentially of said at least one polymer material having a Shore A hardness ranging from 5 to 90, more preferably at least 80% or 90% by mass of said insert consists essentially of said at least one polymer material having a Shore A hardness ranging from 5 to 90.

[0145] In an alternative embodiment, the braided hollow sheath comprises, advantageously is essentially made up of, even more advantageously is made up of, at least 10 strands, preferably at least 14 strands, braided, each of the strands comprising at least one multifilament yarn.

[0146] In an alternative embodiment, the braided hollow sheath comprises, advantageously is essentially made up of, even more advantageously is made up of, one or more threads comprising one or more materials chosen from: high or very high molecular weight polyethylene, polyethylene terephthalate, polypropylene, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polytrimethyleneterephthalate (PTT), or a combination thereof, preferably high or very high molecular weight polyethylene, and polyethylene terephthalate, or a combination thereof. In an alternative embodiment, the height of a braided helix pitch of the braided hollow sheath is greater than or equal to 4 mm, preferably greater than or equal to 8 mm, in particular between 4 mm and 25 mm.

[0147] A braided helix pitch corresponds to the distance separating two crossings of a given braided wire with the longitudinal axis of the hollow braided sheath.

[0148] In an alternative embodiment, the external diameter of the insert is greater than or equal to 0.50 mm, or 0.75 mm or 1 mm, or 2 mm, and less than or equal to 15 mm, preferably less than or equal to 10 mm, more preferably less than or equal to 8 mm or 5 mm or 4 mm or 3 mm. The present invention relates, according to a second aspect, to a method for manufacturing an artificial ligament, in particular according to any one of the variants / embodiments with reference to the first aspect of the invention, advantageously comprising: a) providing a deformable insert, b) a step of braiding a hollow sheath having an interior volume of which at least a portion is overbraided around said deformable insert, said deformable insert being housed in the interior volume of the braided hollow sheath and over at least a portion of the length of said hollow sheath, and the ligament has:

[0149] - a deformation phase A in which the director coefficient ka measured on a traction force (N) - elongation (%) curve Cia of said artificial ligament is less than or equal to 6 Newtons / %, preferably less than or equal to 5 Newtons / %; and

[0150] - a deformation phase B in which the director coefficient kb measured on said curve Ci a tensile force (N) - elongation (%) of said artificial ligament is greater than or equal to 4 Newtons / %, preferably greater than or equal to 5 Newtons / %, and less than or equal to 40 Newtons / %, the elongation of said artificial ligament in said deformation phase B is greater than or equal to 2% and less than or equal to 15%, in particular less than or equal to 10%;

[0151] - a deformation phase C in which the director coefficient kc measured on said curve Q a tensile force (N) - elongation (%) is greater than the direction coefficient kb of phase B.

[0152] In an alternative embodiment, said method comprises a heat-setting step comprising the application of a temperature ranging from 90°C to 300°C, in particular of the order of 130°C, for at least 1 minute, in particular for a period ranging from 2 minutes to 10 minutes. Preferably, a load (applied to the free ends of said artificial ligament) ranging from 1 daN to 10 daN is applied to the artificial ligament during the heat-setting step.

[0153] In one embodiment, the braided hollow sheath comprises (in particular consists essentially of) one or more polyethylene yarn(s), and the temperature applied during the heat-setting step is greater than or equal to 90°C and less than or equal to 300°C.

[0154] In one embodiment, the braided hollow sheath comprises (in particular consists essentially of) one or more polyethylene terephthalate or polybutylene terephthalate yarn(s), and the temperature applied during the heat-setting step is greater than or equal to 150°C and less than or equal to 230°C. Description of the drawings

[0155] The present invention will be better understood by reading the following embodiments, cited without limitation, and illustrated by the figures in which:

[0156] [Fig.l] Figure 1 schematically represents a first example of an artificial ligament according to the invention;

[0157] [Fig.2] Figure 2 schematically represents in enlarged view, the height of a braided helix pitch of the braided hollow sheath of the artificial ligament represented in Figure 1;

[0158] [Fig.3] Figure 3 schematically represents a second example of an artificial ligament according to the invention;

[0159] [Fig.4] Figure 4 schematically represents a second example of a deformable insert suitable for implementing the invention;

[0160] [Fig.5] Figure 5 schematically represents a third example of a deformable insert suitable for implementing the invention;

[0161] [Fig.6] Figure 6 schematically represents a fourth example of a deformable insert suitable for implementing the invention;

[0162] [Fig.7] Figure 7 schematically represents a fifth example of a deformable insert suitable for implementing the invention;

[0163] [Fig.8] Figure 8 schematically represents different Q curves ain which the applied tensile force is indicated on the ordinate, and the elongation obtained (%) is indicated on the abscissa for flat artificial ligaments according to the invention and a hollow braided sheath without insert forming a comparative artificial ligament;

[0164] [Fig.9] Figure 9 schematically represents different Q curves a in which the applied tensile force is indicated on the ordinate, and the elongation obtained (%) is indicated on the abscissa for substantially tubular artificial ligaments according to the invention and two hollow braided sheaths without insert forming comparative artificial ligaments.

[0165] The curves shown in Figures 8 and 9 are obtained for traction cycles that do not go as far as ligament rupture but for a maximum applied traction force of approximately 250 Newtons. These curves Q atensile force - elongation of said artificial ligament are measured as described above in this text, i.e. on a Llyod Lrx Plus machine, with a tensile speed of 100 mm / minute, in particular at room temperature, for example at a temperature ranging from 19°C to 23°C, without any particular relative humidity condition, possibly a pretension of IN to ION is applied, in particular at a preload speed of 50 mm / min. The artificial ligament comprises in particular first and second ends, a first end is arranged in first jaws, and a second end is arranged in the second jaws, the first jaws are fixed while the second jaws move in translation at a speed of 100 mm / minute. Preferably, the initial test length of the artificial ligament is 395 mm + / - 5 mm.

[0166] Description of the embodiments

[0167] The first example of artificial ligament 10 according to the invention comprises a hollow braided sheath 20 defining an interior volume 22 and having a length L gci determined as well as first and second opposite ends (24,26). The artificial ligament 10 also comprises a deformable insert 30 having a length Lu and first and second opposite ends (34,36). In this specific example, the deformable insert 30 is a flat, solid polyurethane rod having a Shore A hardness of approximately 40. In particular, the length Lu is less than L gci but could be equal to L gc i.

[0168] The propeller pitch P hi of the hollow braided sheath 20 is in this specific example of the order of 11 mm. The braided helix pitch corresponds to the distance P hi separating two adjacent crossings of a braided wire - colored black for identification purposes in Figure 2 - with the longitudinal axis of the hollow braided sheath 20.

[0169] In this specific example, the artificial ligament 10 comprises 16 strands each comprising a 435 dtex, 120 filament polyethylene terephthalate multifilament yarn, said strands being braided on a 16-spindle braiding machine (one strand / spindle).

[0170] The second example of artificial ligament 100 according to the invention comprises a hollow braided sheath 120 defining an interior volume 122 and having a length L gc2 determined as well as first and second opposite ends (124,126). The artificial ligament 100 also comprises a deformable insert 130 having a length L i2 and first and second opposite ends (134,136). In this specific example, the deformable insert 130 is a solid cylindrical polyurethane rod having a Shore A hardness of approximately 40. In particular, the length L i2 is less than L gc2 but could be equal to L gc2 .

[0171] The propeller pitch P h2 of the hollow braided sheath 120 is in this specific example of the order of 19 mm.

[0172] In this specific example, the artificial ligament 100 comprises 48 strands each comprising 4 multifilament threads made of polyethylene terephthalate, each of the threads having a fineness of 138 dtex and comprising 32 filaments. The 48 strands are braided on a braiding machine with 48 spindles (one strand / spindles). In the present text, the number of braided strands corresponds to the number of spindles supporting one or more threads (a strand may comprise one or more threads) which are braided on the braiding machine.

[0173] The braided sheath 120 has more braided strands and is thus less tightly packed around the insert 130 than the braided sheath 20 which is very tightly packed around the insert 30.

[0174] In order to shift the rigid behavior of the hollow braided sheath under the effect of longitudinal traction, in particular in phase C of deformation, the wires of the sheath are braided so as to penetrate / engage on the surface of the insert, i.e. with a helix pitch large enough for the wires to slide relative to each other.

[0175] In the examples shown in Figures 1 to 3, the insert (30, 130) is a flat, solid rod made of elastic and deformable polyurethane. This insert may alternatively be, for example, an extruded or foamed polymer profile 200 having a trilobed cross-section as shown in Figure 4 or quadrilobed 210 as shown in Figure 5 or a hollow rod such as a tube. The diameters d ini and d in2 respectively inserts 200 and 210 (i.e. the diameter of the circle receiving the cross-section of said insert) are for example each of the order of 4 mm. The insert according to the invention can also be a spring profile 220 having a height h in3 ranging from 2 mm to 8 mm, for example of the order of 4 mm, a width l in3 ranging from 1 mm to 8 mm, for example of the order of 5 mm. The thickness of a wall e in3 ranges from 0.1 mm to 2 mm, for example is of the order of 0.4 mm. The insert according to the invention may also be a textile strip 230 in honeycomb knitted and wound on itself to form a tube around which the hollow sheath is braided.

[0176] Preferably, the insert according to the invention is a rod (in particular hollow or solid) made of polyurethane or polycarbonate-urethane (PCU), or even polydimethylsiloxane (PDMS).

[0177] Figure 8 represents the curves of longitudinally applied tensile force (N) and elongation obtained (%) for a comparative artificial ligament LAC1 and three artificial ligaments according to the invention whose hollow braided sheaths are substantially flat LAI1, LAI2, and LAI3, and this for a maximum applied tensile force of 250 Newtons.

[0178] Example LAC1

[0179] This comparative artificial ligament comprises a hollow textile sheath braided on a 48-spindle braiding machine, and therefore comprises 48 textile strands, each textile strand comprises 4 polyethylene terephthalate threads, each thread comprises 32 filaments and has a count of 138 dtex. 552 dtex is obtained per strand. The helix pitch is approximately 19.64 mm. Example LAI1

[0180] This artificial ligament according to the invention comprises a hollow textile sheath braided on a 48-spindle braiding machine, and therefore comprises 48 textile strands, each textile strand comprises 4 polyethylene terephthalate threads, each thread comprises 32 filaments and has a count of 138 dtex. 552 dtex is obtained per strand. The helix pitch is approximately 19.64 mm. This artificial ligament comprises an insert formed from a flat, solid polyurethane rod with a Shore A hardness of approximately 40, having a length Lin of approximately 13.5 cm, a width lin of approximately 6.5 mm and a thickness of approximately 4 mm. The length of the hollow textile sheath Lgc is substantially equal to the length lin of the insert.

[0181] Example LAI2

[0182] This artificial ligament according to the invention comprises a hollow textile sheath braided on a 48-spindle braiding machine, and therefore comprises 48 textile strands, each textile strand comprises 4 polyethylene terephthalate threads, each thread comprises 32 filaments and has a count of 138 dtex. 552 dtex is obtained per strand. The helix pitch is approximately 19.64 mm. This artificial ligament comprises an insert formed from a flat, solid rod made of polyurethane with a Shore A hardness of approximately 40, having a length Lin of approximately 10.5 cm, a width lin of approximately 5 mm and a thickness of approximately 4 mm. The length of the hollow textile sheath Lgc is substantially equal to the length lin of the insert.

[0183] Example LAI3

[0184] This artificial ligament according to the invention comprises a hollow textile sheath braided on a 48-spindle braiding machine, and therefore comprises 48 textile strands, each textile strand comprises 4 polyethylene terephthalate threads, each thread comprises 32 filaments and has a count of 138 dtex. 552 dtex is obtained per strand. The helix pitch is approximately 19.64 mm. This artificial ligament comprises an insert formed from a flat, solid rod made of polyurethane with a Shore A hardness of approximately 40, having a length Lin of approximately 10.5 cm, a width lin of approximately 5 mm and a thickness of approximately 4 mm. The length of the hollow textile sheath Lgc is substantially equal to the length lin of the insert.

[0185] The LAC1, LAI1, LAI2, and LAI3 ligaments all undergo a calendering step during which they are calendered and heated, notably at 110°C for 45 seconds, to flatten them and fix this shape. The LAC1, LAI1, and LAI2 ligaments also undergo a heat-setting step, unlike the LAI3 ligament, which does not undergo a heat-setting step.

[0186] In these specific examples, and in a non-limiting manner, the heat-setting step comprises heating the artificial ligament under tension under a load (preferably applied to the free ends of said artificial ligament) ranging from 1 daN to 10 daN, in particular 10 daN. The heating time is greater than or equal to 2 min and less than or equal to 10 min, and the heating temperature is greater than or equal to 90°C and less than or equal to 300°C. When the braided hollow sheath is composed of polyethylene yarns, the heating and therefore heat-setting temperature is preferably greater than or equal to 80°C and less than or equal to 120°C. When the braided hollow sheath is composed essentially of polyethylene terephthalate or polybutylene terephthalate yarn(s), the heating and therefore heat-setting temperature is greater than or equal to 150°C and less than or equal to 230°C.

[0187] It is observed that the LAC1 ligament does not comprise phases A and B and begins the stiffest phase C almost immediately after the application of the tensile force (N). The ligaments according to the invention LAI1, LAI2 and LAI3 have their deformation phases C which are offset by the deformation phases A and B. Phase A appears as a deformation plateau in which the ligament lengthens for a nearly zero tensile force with a low elongation, in particular substantially less than or equal to 2%.

[0188] Phase B of deformation, intermediate between phases A and C, presents an elongation which remains moderate, less than or equal to 4% for a force applied which is still quite modest, in particular less than or equal to 100N. Finally, in phase C of deformation, the LAI1, LAI2 and LAI3 ligaments elongate much more but for much higher applied forces, for example greater than or equal to 100N.

[0189] For example, on the LAI1 curve we measure a direction coefficient ka of the order of 4 N / %, a direction coefficient kb of the order of 5.5 N / %, and a direction coefficient kc at a first point (bottom of the curve) of 27.07 N / % and at a second point (middle of the curve) of 41.68 N / %.

[0190] Figure 9 represents the curves of longitudinally applied tensile force (N) and the elongations obtained (%) for two comparative artificial ligaments LAC2 and LAC3, and two artificial ligaments according to the invention LAI4, LAI5, whose hollow braided sheaths are substantially round, and this for a maximum applied tensile force of 240 Newtons.

[0191] Example LAC2

[0192] This comparative artificial ligament comprises a hollow textile sheath braided on a 16-spindle braiding machine, and therefore comprises 16 textile strands, each textile strand comprises 1 very high molecular weight polyethylene thread, for example of the Spectra brand, each thread comprises 120 filaments and has a count of 435 dtex. This ligament does not include a deformable insert. The helix pitch P h is 11 mm. Example LAC3

[0193] This comparative artificial ligament is similar to the LAC2 ligament except that the helix pitch P h is 5 mm.

[0194] Example LAI4

[0195] This artificial ligament according to the invention comprises a hollow textile sheath braided on a 16-spindle braiding machine, and therefore comprises 16 textile strands, each textile strand comprises 1 very high molecular weight polyethylene thread, for example of the Spectra brand, each thread comprises 120 filaments and has a count of 435 dtex. The helix pitch p h is 11 mm.

[0196] This artificial ligament comprises a laminate wound on itself with a length Lin of approximately 10 cm and a width lin of approximately 6 mm. The length of the hollow textile sheath Lgc is approximately equal to the length lin of the insert. The pre-tension applied before establishing the force-elongation curve is 200 g.

[0197] Example LAI5

[0198] This artificial ligament according to the invention comprises a hollow textile sheath braided on a 16-spindle braiding machine, and therefore comprises 16 textile strands, each textile strand comprises 1 very high molecular weight polyethylene thread, for example of the Spectra brand, each thread comprises 120 filaments and has a count of 435 dtex. The helix pitch p h is 11 mm.

[0199] This artificial ligament comprises a laminette (an openwork knit, such as that shown in Figure 7) wound on itself having a length Lin of approximately 10 cm, a width lin of approximately 6 mm. The length of the hollow textile sheath Lgc is substantially equal to the length lin of the insert. The pre-tension applied before establishing the force-elongation curve is 300 g.

[0200] For example, on the LAI4 curve, we measure a direction coefficient ka of almost 0 N / %, a direction coefficient kb of the order of 12 N / %, and a direction coefficient kc of the order of 133. The behavior of the artificial ligaments LAI4 and LAI5 are similar to the ligaments LAI1-3: we observe a phase A of deformation similar to a plateau, then a start of the curve foot in phase B in which the elongation remains moderate under an equally moderate force, and a rigidity which increases strongly in the deformation phase C. The direction coefficient kb is thus greater than or equal to 3 times the direction coefficient ka, likewise the direction coefficient kc is greater than or equal to 3 times the direction coefficient kb.

Claims

CLAIMS Artificial ligament (10,100), in particular for the treatment of proximal junctional kyphosis, characterized in that said artificial ligament (10,100) comprises an elongated hollow braided sheath (20,120) having an interior volume (22,122), and a deformable insert (30,130,200,210,220,230) housed in the interior volume (22,122) of the hollow braided sheath (20,120) and this over at least part of the length of said hollow sheath (20,120), in that the artificial ligament (10.100) has: - a deformation phase A in which the director coefficient ka measured on a curve Ci a tensile force (N) - elongation (%) of said artificial ligament (10,100) is less than or equal to 6 Newtons / %; and - a deformation phase B in which the director coefficient kb measured on said curve Ci a tensile force (N) - elongation (%) of said artificial ligament (10.100) is greater than or equal to 4 Newtons / % and less than or equal to 40 Newtons / %, the elongation of said artificial ligament (10.100) in said deformation phase B is greater than or equal to 2% and less than or equal to 15%; - a deformation phase C in which the director coefficient kc measured on said curve Ci a tensile force (N) - elongation (%) of said artificial ligament (10,100) is greater than the director coefficient kb of phase B. Artificial ligament (10,100) according to claim 1, characterized in that the deformable insert (30,130,200,210,220,230) is a rod, or an extruded polymer profile, comprising a thermoplastic or thermosetting elastomer, preferably comprising one or more polymer(s) chosen from: a polyurethane, a polycarbonate-urethane, a polydimethylsiloxane, or a mixture of these. Artificial ligament (10,100) according to either of claims 1 and 2, characterized in that the difference (%) between the residual elongation (%) obtained after a traction cycle n of said ligament (10,100) and the residual elongation (%) obtained after a traction cycle n+1 of said ligament, with n being an integer other than 0, preferably n being equal to 10, is less than or equal to 15%, each traction cycle comprising the application of a traction force of the order of 250 Newtons. Artificial ligament (10,100) according to any one of claims 1 to 3, characterized in that - in phase A of deformation, the elongation of said artificial ligament (10,100) is less than or equal to 5% for a tensile force greater than 0 Newtons and less than or equal to 20 Newtons; and - in deformation phase C, the elongation of said artificial ligament (10,100) is greater than or equal to 5%, in particular less than or equal to 50%, for a tensile force greater than or equal to 200 Newtons and less than or equal to 800 Newtons. Artificial ligament (10,100) according to any one of claims 1 to 4, characterized in that the direction coefficient kb is greater than the direction coefficient ka. Artificial ligament (10,100) according to any one of claims 1 to 5, characterized in that the direction coefficient kc is greater than or equal to 3 times the direction coefficient kb. Artificial ligament (10,100) according to any one of claims 1 to 6, characterized in that the elongation of the artificial ligament (100,100) is less than or equal to 5% under the application of a tensile force less than or equal to 40 Newtons.Artificial ligament (10,100) according to any one of claims 1 to 7, characterized in that the interior volume (22,122) of said at least one part of the braided hollow sheath (20,120) receiving said insert (30,130,200,210,220,230) comprises one or more compressible empty cavities so as to collapse during the transition from deformation phase A to deformation phase B. Artificial ligament (10,100) according to any one of claims 1 to 8, characterized in that the solid surface (mm. 2 ) of the cross-section of the insert is less than the total surface area (mm 2 ) of the cross-section of said at least one part of the hollow braided sheath (20,120) receiving said insert (30,130,200,210,220,230) in its interior volume (22,122). Artificial ligament (10,100) according to any one of claims 1 to 9, characterized in that the insert (30,130,200,210,220,230) is chosen from: a tube, a foam, and at least one elongate element, in particular at least one rod or at least one monofilamentary thread, more particularly multilobed. Artificial ligament (10,100) according to any one of claims 1 to 10, characterized in that the insert (30,130,200,210,220,230) is an elongate element extruded, foamed or printed in three dimensions, in particular by additive or subtractive manufacturing or a combination thereof. Artificial ligament (10,100) according to any one of claims 1 to 11, characterized in that said insert (30,130,200,210,220,230) comprises one or more polymer material(s) having a Shore A hardness ranging from 5 to 90, in particular ranging from 5 to 50, more particularly ranging from 20 to 50.Artificial ligament (10,100) according to any one of claims 1 to 12, characterized in that the braided hollow sheath (20,120) comprises at least 10 strands, preferably at least 14 strands, braided, each of the strands comprising at least one multifilament yarn. Artificial ligament (10,100) according to any one of claims 1 to 13, characterized in that the braided hollow sheath (20,120) comprises one or more yarns comprising at least one material chosen from: very high molecular weight polyethylene, polyethylene terephthalate, polypropylene, polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polytrimethyleneterephthalate (PTT).Artificial ligament (10,100) according to any one of claims 1 to 14, characterized in that the height of a braided helix pitch of the braided hollow sheath (20,120) is greater than or equal to 4 mm, preferably greater than or equal to 8 mm, in particular is greater than or equal to 4 mm and less than or equal to 25 mm. Artificial ligament (10,100) according to any one of claims 1 to 15, characterized in that the external diameter of the insert (30,130,200,210,220,230) is greater than or equal to 0.5 mm and less than or equal to 15 mm. A method of manufacturing an artificial ligament (10,100), in particular according to any one of claims 1 to 16, characterized in that it comprises: a) providing a deformable insert (30,130,200,210,220,230), b) a step of braiding a hollow sheath (20,120), having an interior volume (22,122), around said deformable insert (30,130,200,210,220,230), said deformable insert being housed in the interior volume (22,122) of the braided hollow sheath (20,120) and this over at least part of the length of said hollow sheath, and in that the ligament has: - a deformation phase A in which the director coefficient ka measured on a curve Ci a tensile force (N) - elongation (%) of said artificial ligament (10,100) is less than or equal to 6 Newtons / %; and - a deformation phase B in which the director coefficient kb measured on said curve Ci atensile force (N) - elongation (%) of said artificial ligament (10,100) is greater than or equal to 4 Newtons / % and less than or equal to 40 Newtons / %, the elongation of said artificial ligament (10,100) in said deformation phase B is greater than or equal to 2% and less than or equal to 15%; - a deformation phase C in which the director coefficient kc measured on said curve Q a tensile force (N) - elongation (%) of said artificial ligament (10,100) is greater than the director coefficient kb of phase B.

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