WO1995027449A1 - Prothese de ligament croise - Google Patents

Prothese de ligament croise Download PDF

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Publication number
WO1995027449A1
WO1995027449A1 PCT/GB1995/000836 GB9500836W WO9527449A1 WO 1995027449 A1 WO1995027449 A1 WO 1995027449A1 GB 9500836 W GB9500836 W GB 9500836W WO 9527449 A1 WO9527449 A1 WO 9527449A1
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WO
WIPO (PCT)
Prior art keywords
fixator
bone
tensile
tensile element
hydrogel
Prior art date
Application number
PCT/GB1995/000836
Other languages
English (en)
Inventor
David Martin Pickles
Allen Edward Goodship
Donald James Highgate
Robert Andrew Scott
Original Assignee
The Secretary Of State For Health In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Secretary Of State For Health In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland filed Critical The Secretary Of State For Health In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland
Priority to AU22190/95A priority Critical patent/AU2219095A/en
Priority to GB9620916A priority patent/GB2302029B/en
Priority to EP95915247A priority patent/EP0749292A1/fr
Publication of WO1995027449A1 publication Critical patent/WO1995027449A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/08—Muscles; Tendons; Ligaments
    • A61F2/0811—Fixation devices for tendons or ligaments
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/34—Macromolecular materials
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/52—Hydrogels or hydrocolloids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/08—Muscles; Tendons; Ligaments
    • A61F2/0811—Fixation devices for tendons or ligaments
    • A61F2002/0817—Structure of the anchor
    • A61F2002/0823—Modular anchors comprising a plurality of separate parts
    • A61F2002/0835—Modular anchors comprising a plurality of separate parts with deformation of anchor parts, e.g. expansion of dowel by set screw
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/08—Muscles; Tendons; Ligaments
    • A61F2/0811—Fixation devices for tendons or ligaments
    • A61F2002/0847—Mode of fixation of anchor to tendon or ligament
    • A61F2002/0864—Fixation of tendon or ligament between anchor elements, e.g. by additional screws in the anchor, anchor crimped around tendon
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/08—Muscles; Tendons; Ligaments
    • A61F2/0811—Fixation devices for tendons or ligaments
    • A61F2002/0876—Position of anchor in respect to the bone
    • A61F2002/0882—Anchor in or on top of a bone tunnel, i.e. a hole running through the entire bone
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2210/0061—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof swellable

Definitions

  • the present invention relates to novel ligament prostheses, and bone-fixators allowing improved function of such prostheses; particularly relating to anterior cruciate ligament (ACL) prostheses.
  • ACL anterior cruciate ligament
  • biomechanical properties of the prosthesis should satisfactorily match those of the natural ACL, in the following respects: (i) sufficient overall tensile strength; (ii) satisfactory mimicking of force/deformation profile low and high modulus regions; (iii) minimal hysteresis; (iv) minimal creep; (v) excellent elastic recoverability.
  • the inventors have paid special attention to measuring ACL strain in the walking animal using implanted displacement transducers to determine the physiological strain environment of the ligament.
  • the force deformation profile of the ACL shows a characteristic toe region where the modulus starts low and increases to a linear, relatively high value.
  • the toe region of the ACL may have an important role in defining the complex motion of the knee joint, which shows gliding of the femoral condyles over the tibial condyles as the joint rotates and the leg extends.
  • the inventors have found that use of prostheses based on synthetic braids alone does not provide particularly good matching of the 'toe 1 region. In order to achieve the two domains of markedly differing mechanical properties they have then turned their attention to choice of a composite prosthesis design, using correspondingly different materials.
  • the present inventors have now accurately quantified the properties of the ACL and have succeeded in developing a biomechanically-matched prosthesis which aims to prevent prosthesis wear and to maintain a physiological gauge length; these being features which no other conventional system can achieve.
  • the prostheses may be used for replacement of the natural ligament in animals in general, with the dimensions and strengths of materials matched to its weight or particular requirements, but is particularly intended for human use.
  • the inventors have found that in order to achieve the improvement required it is possible to use a continuous, prestressed hydrophilic element in conjunction with a synthetic braid whereby a radically new approach to the problem of fixation and initial tensioning of the ACL during surgical implantation is provided.
  • Hydrophilic polymeric materials are characterized by the ability to take in large amounts of water and reach a state of stable hydration without suffering solution or long term degradation. Equilibrium water contents of 10 - 98% by wet weight may be readily achieved. During absorption of water hydrophilic material normally swells isotropically and changes from a hard, rigid structure, becoming soft and elastic. It may be accurately machined and polished while dry, and is subsequently hydrated to become soft, conforming and biocompatible. The linear expansion ratio (Xwet/Xdry) , which lies typically between 1.1 and 3>5t may be accurately controlled. Hydrophilic polymers have been used extensively in contact lens applications, and also in stoma care dressings which necessitate subcutaneous implantation for biocompatibility assessment. More recently, hydrogels have been used as dusting powder in surgical gloves. There have been no reports of adverse reactions.
  • hydrophilic materials such as those used for contact lenses
  • hydrophilic materials have a low 'notch-tear 1 strength.
  • interpenetrating systems particularly those based upon acrylonitrile polymers, which combine good elasticity with high notch tear strength can be 1 prestressed' when dry so that on hydration the system may contract in one or two dimensions.
  • the axial length of a dry hydrogel rod may be arranged to either increase, remain the same, or decrease by any contraction ratio up to 5 ⁇ 1 ⁇ in the latter case there is of course a lateral expansion due to the hydration of the material and the axial expansion.
  • hydrophilic material could be used as a stand-alone prosthesis, since all such substances are too elastic to provide the necessary tensile properties.
  • it may be used in two ways to generate a low modulus region to a prosthesis: firstly, as a core inserted inside an external sheath which would provide the required strength, or secondly, as a continuous metric containing a dispersion of reinforcing fibres. In the latter instance the hydrogel needs to be cast with the appropriate fibre elements in situ. In both cases the hydrogel would act in compression resisting the tendency for the prosthesis tensile component to collapse inwards under axial load.
  • hydrophilic polymer material allows a prosthesis to be manufactured chemically complete before implantation but that changes shape permanently in a controllable and reproducible fashion upon exposure to tissue fluids. Furthermore experience with soft contact lenses has shown the materials to be extremely mechanically stable in fatigue testing.
  • a first aspect of the present invention provides a ligament prosthesis tensile element comprising a prestressed hydrogel material and a non-degradable fibrous material; the fibrous material being provided in at least one of the ends of the tensile element and the hydrogel being that which expands to prevent the fibrous material from collapsing toward the element longitudinal axis under physiological load.
  • the fibrous material runs the entire length of the tensile element and is provided as a sheath, or as fibres embedded in the hydrogel.
  • the hydrogel expands more axially than radially.
  • the prosthesis tensile element has a tubular outer sheath, preferably a biocompatible braid, in which the tensile element engaging element is positioned in use.
  • the braid is conveniently any biocompatible material capable of load bearing, such as non -impregnated or impregnated polymeric braid.
  • One convenient material is polyester braid in the form of a cord.
  • Such braid cords may be provided in a variety of strengths and sizes and are readily available form such sources as English Braids Ltd, Spring Lane, Malvern, Worcestershire, WR14 1AL United Kingdom.
  • the present inventors have determined that by varying primarily the diameter of the hydrogel core, and secondarily, its nature (i.e. chemical species/water content etc) the mechanical properties of the hydrogel-braid composite can be made to match those of the natural structure.
  • the interrelationship of braid lay angle and core diameter has been demonstrated; use of a prestressed hydrogel core means that the lay angle is recoverable following a load cycle.
  • the braid should biomechanically match the ligament it is to replace.
  • an English Braids Ltd R27K braid cord may be used having 2.7mm diameter with yarns to a total of 1500 denier or metric equivalent of 1550 decitex. These cords are sold with a centre core which is added to maintain roundness, and this is removed and filled with hydrogel when preparing the prosthesis tensile element.
  • the braid is filled with a hydrogel core that expands on further hydration with water such as to give the tensile element a full resilient nature.
  • a hydrogel core that expands on further hydration with water such as to give the tensile element a full resilient nature.
  • Many suitable hydrogels will be known to those skilled in the art. Preferred such gels have linear expansion ratios of 1.0:1.0 to 1.8:1, with gels of ultimate water content between 20 and 80%. More preferably the linear expansion ratios of is around 1.2:1.0 and the ultimate water content is around 30 .
  • Hydrogel cores are conveniently formed as rods and machined in unhydrated form down to desired diameter for threading down the braid. For the sheep prosthesis this is about 13 mm. Rehydration is achieved eg. by immersion in isotonic saline prior to testing but can be rehydrated to below its ultimate water content prior to implantation.
  • the prosthesis tensile element is provided with a further sheath, also of biocompatible material, positioned around the prosthesis tensile element such that the tensile element can slide therein.
  • this further sheath is such that it allows, or even stimulates, growth of tissue around it such as to fix the prosthesis in place with time.
  • the interface should be designed to allow prosthesis tensile elements, particularly those provided with such a prestressed core, to act in a manner closely matched to natural ligaments and should further permit satisfactory prosthesis tensioning to be applied at implantation and preferably allowing retensioning in the future should the need arise.
  • the overall prosthesis length will be largely dependent on the geometry of a given knee joint and will not be known prior to the operation. Such variation must be accommodated into the design.
  • the gap between the end of the hydrogel and the fixator should be filled appropriately to avoid discontinuity in the material properties of the whole structure. The length of the gap will relate to the overall length.
  • the present invention seeks to anchor the substance of the prosthesis to the bone using a a fixator element capable of being anchored in a bone, and an interface for attachment of the tensile element characterised in that the interface has a tensile element engaging element comprising a solid body capable of being gripped by the fixator element such that the fibrous material of the prosthesis is trapped between the body and the fixator element.
  • the sections may take the form either of small shims of different lengths to be selected by the surgeon at implantation and are intended to be inserted down the ends of the braid during assembly, or as a portion of the material embedded into a hollow cavity at the tip of the engaging element.
  • the sections should preferably be of the diameter of the tensile element within the sheath but expand axially on hydration, in vivo or in vitro, to take up slack.
  • the hydrogel shims may be provided such that they can be inserted into the tensile element sheath by the surgeon installing the prosthesis as required in order to take up any slack in the braid. It may be desired that such shims, or the core itself, only expand in particular directions, eg. axially rather than radially. Such capability is provided by use of hydrogels such as those described in GB 1566552 (Highgate) . In the further option where the engaging element incorporates a hydrogel insert this is similarly biased such that it expands only in one direction on further hydration when in situ (ie. in the animal or patient). This gel may be formed with a number of hollows therein in order that expansion within the element is avoided or reduced.
  • a bone-fixator for affixing a prosthesis tensile element comprising a fibrous material to a bone, comprising a fixator element capable of being anchored in a bone, and an interface for attachment of the tensile element characterised in that the interface has a tensile element engaging element comprising a solid body capable of being gripped by the fixator element such that the fibrous material is trapped between the body and the fixator element.
  • the fibrous material is uniformly distributed around one or more cross sections of the solid body, and most preferably is provided as a sheath into which the solid body locates in use.
  • the sheath containing the body is inserted into a bore in the fixator element and the portion of the sheath around the body is firmly gripped between them to lock in position.
  • the fixator element may already be fixed into a bone or fixed later.
  • the solid body is formed to have a width that increases from that which will fit into the unexpended braid to that which is greater in width than the unexpended braid diameter and preferably then reduces again, most preferably with conical or parabolic shaped axial ends.
  • This is preferably a bullet-like element with concentric interference-fitting conical faces (an axial bullet) such that it can be driven into firm interference fit with the fixator element by use of a force sensitive tool.
  • the body may for example be locked in place using a locking element on the fixator, such as a locking nut.
  • a such a solid body allows the tensile element length to be adjusted axially by inserting it through a bore in the fixator element, inserting the engaging element, eg. bullet shaped body, into the end of the tensile element such that it is sheathed thereby, adjusting the length of tensile element to that required and then securing the engaging element into engagment with the fixator element.
  • the engaging element eg. bullet shaped body
  • tension in the prosthesis must be selected by the surgeon at implantation, after which it cannot be adjusted.
  • the engaging element eg. bullet body
  • the engaging element may be retracted, and braid drawn back through the fixator to the appropriate tension, and the element engaged again.
  • the fixator comprises an inner fixator element which can moved within an outer bone-engaging element (eg. a self tapping hollow bone screw) .
  • an outer bone-engaging element eg. a self tapping hollow bone screw
  • the inner element is slidably mounted within the outer bone engaging element and can be retracted into it or extended out from it by means of a threaded collar thereby allowing fine-tuning of the tension of the tensile element once the device is in its final position.
  • relative rotation between the fixator element and the bone-engaging element is limited by means of a cooperating lug/groove or other rotation-resisting arrangement.
  • the use of a separate inner fixator element which can be located within an outer bone-engaging element permits the preassembly of a readily fixatable tensile unit before surgery.
  • an appropriate length of tensile element may be secured at each end to an inner element fixator.
  • a set of several such preassembled units of different lengths is supplied to a surgeon who can, during the operation, select the most appropriate for his patient. The unit can then be threaded through bone screws after they have been implanted, and fine tuning of the tension can then be carried out using the threaded collar.
  • a third aspect of the invention comprises such a unit comprising a suitable fibrous tensile element attached to one or two inner fixator elements as described above.
  • the devices of the present invention would be far more suitable for a revision operation than any existing prosthesis, since the bone fixators would be left in situ and a replacement braid/hydrogel unit could be fitted without further interference to the bone.
  • the tensile unit i.e. tensile element plus one or both inner fixators
  • the tensile unit could be changed.
  • a prosthesis and fixator assembly comprising a tensile element, a fixator element and a tensile element engaging element; all as described above.
  • Figure 1 shows a typical force deformation curve for collagenous tissue of a sheep anterior cruciate ligament.
  • Figure 2 shows force strain curves for number of hydrogel cored braids as described in Table 1 as compared to a natural ACL.
  • Figure 3 shows a plot of peak force achieved during application of 10% uniaxial strain to specimens described in Table 1.
  • Figure 4 shows a plot of normalised stiffness of the linear elastic portion of the force strain curve during application of 10% uniaxial strain v log (cycle number) for each specimen of Table 1.
  • Figure 5- shows a plot of normalised energy loss (hysteresis) against log (cycle number) during tensile testing for the specimens of Table 1.
  • Figure 6 shows a plot of braid lay angle as a function of applied load for the specimens of Table 2.
  • Figure 7- shows a schematic diagram of a bone fixator/prosthesis tensile element interface of the present invention in end view (a) and a longitudinal cross section (b) , the prosthesis engaging element being held in a locked condition by interference fit between its surfaces and the fixator provided by impacting the two together under a measured torque.
  • Figure 8 shows a schematic cross section of a unit according to the present invention comprising a prosthesis tensile element wherein each end is attached to a fixator body in readiness for connection to a bone screw.
  • Figure 9 shows a cross section through an interface as described in Figure 7 but wherein a hydrogel core element is incorporated in the end of the engaging element for the purpose of taking up slack.
  • EXAMPLE 1 Provides of prosthesis tensile element cores.
  • R27K 2.7mm diameter multifilament polyester braided cord provided with a central core.
  • the cover is braided using a 16 carrier machine, 8 going cw and 8 going acw.
  • Each carrier has a yarn or yarns to the total of 1500 denier or the metric equivalent of 1550 decitex; usually 1 x 1500 or alternatively 1 x 1000 plus 1 x 500 denier.
  • the polyester yarn from which this and other English Braids Ltd products is of 1000 denier (1100 decitex), 1117 Grams per 10000m with a breaking load of 89.2N, tenacity 79 «9cN/tex, extension at break 13.8%, tensile shrinkage at 180°C of 14.1% and oil content 0.6%.
  • a number of hydrogel core/braid sheathed tensile elements were prepared having properties as set out in Table 1. Hydrogel used was
  • Figure 1 there is shown a typical force deformation curve for collagenous tissue wherein a uniaxial tensile test of a sheep anterior cruciate ligament is shown.
  • the specimen was well conditioned by repeated cycling, and the origin of the curve (zero strain, zero load) is defined as the point where load is just detectable, determined by repetitive fitting of cubic polynomial, Riemersa and Van den Bogart, Acta Anatomica, (1992).
  • a regression line has been fitted to the linear portion of the curve, defining the toe and linear elastic regions of the force-strain curve.
  • Tests then consisted of cycling to a 10% strain at a rate of 2%/sec. Following a single conditioning cycle, after which the machine was re-zeroed, the specimen was cycled 111 times: force-displacement data was recorded on a PC at 50Hz for cycles 1-11 and 31, 4l, 51. 61, 71. 81, 91. 101 and 111. Comparable experiments were also carried out for 'empty' R27K braid, and for a sheep anterior cruciate ligament in vitro, still attached to femur and tibia and mounted in special clamps to permit uniaxial tensile testing. The complete force-strain curve (ie applying and removing tension) is shown.
  • Figure 3 shows the peak force achieved during application of 10% uniaxial strain to each specimen described in Table 1, plotted against log(cycle number) . The final point on each line corresponds to the cycle plotted in Fig 2.
  • Figure 4 shows the stiffness of the linear elastic portion of the force-strain curve during application of 10% uniaxial strain to each specimen described in Table 1 plotted against log(cycle). number) .
  • Stiffness was evaluated as the slope of a line drawn between the 100N and 240N data points, and normalising this for variation in specimen length by multiplying by gauge length. Stiffness was not measured for specimen PR39 since the linear elastic region of the curve was not attained within the test.
  • Figure 5 shows the energy loss (ie. hysteresis) during tensile testing of each specimen described in Table 1, plotted against log(cycle number) .
  • Hysteresis was evaluated by measuring the difference in the areas under the tensile and relaxing phases of each cycle, using a computer algorithm.
  • EXAMPLE 2 Bra-it- lav anglp nf prosthesis tensile element cores.
  • hydrogel core/braid sheathed tensile elements were prepared having properties as set out in Table 2. Hydrogel used was
  • Figure 6 demonstrates how the configuration of a braid is precisely controlled by the diameter of the hydrogel core within.
  • Each specimen braid of Table 2 was loaded and unloaded experimentally and the angle subtended by its constituent fibres to the loading axis was monitored using the crosshairs of a travelling microscope.
  • the initial braid lay angle is dependent on the nature of the hydrogel insert and the recoverability of initial braid lay angle (an important feature in a braid prosthesis) is much improved in the hydrogel containing the large diameter hydrogel core.
  • FIG. 7 shows a schematic diagram of a bone fixator/prosthesis tensile element interface in end view (a) and a longitudinal cross section (b).
  • the prosthesis engaging element consists of a steel cone body (1) within the bore of a braided sleeve (2), fitted inside a steel bone fixator (3).
  • the fixator (3) is slidable mounted within a bone screw (4) and is secured therein by a collar (5). Rotation between the fixator and the bone screw is limited by slots in the fixator (6) one of which cooperates with a lug (7) on the inner surface of the bone screw. For precision tensioning the fixator can be longitudinally relocated within the bone screw by means of a mutual thread between the fixator and the collar.
  • Tensioning may also be achieved by moving the braid within the fixator. In either case the braid is locked in position by torquing down the steel cone body using tool (8) to (eg. using around 1500 N controlled force) provide an interference fit between it and the fixator with the braid between the two.
  • Figure 8 shows a schematic cross section of a tensile unit comprising a braid (2) wherein each end is secured to a fixator (3) by a torqued down steel cone body (1).
  • Figure 9 shows an engaging element and tool (8) in place where the element body tip is hollow as shown, open at its narrow end, and filled with dehydrated, prestressed hydrophilic insert (9). On hydration, the insert expands out of the cone to fill the gap between the core in the braid (2) and body (1).
  • inclusion of known and controlled void spaces (10) in the hydrophilic material allows the pressure exerted on the end of the core after hydration may be adequately controlled. This concept is known with regard to a patented design of tooth root filling.
  • the bone screw (4) is implanted as follows.
  • the surgeon identifies the femoral or tibial fixation site and drills a pilot hole using a guide wire. Leaving that in place, a larger hole is bored towards the joint centre using a stepped reamer: this leaves external holes in the tibia and femoral condyle large eneough to accept the bone screw and internal holes in the articular surface just large enough to accept the fixator.
  • the bone screw is inserted using a custom wrench which engages the hexagonal top of the screw and terminates in a round rod of similar diameter to the fixator which temporarily engages in the smaller hole in the articular surface to maintain concentricity as the bone screw is driven home.
  • fixator or fixator/tensile element unit, is then secured to the bone screw such that the end of the fixator is flush with the articular surface, thereby preventing the braid from abrainding against the sharp exit of the bone tunnel and maintaining the active length of the prosthesis as close as possible to that of the natural ligament.

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  • Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Transplantation (AREA)
  • Veterinary Medicine (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Chemical & Material Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • Dermatology (AREA)
  • Epidemiology (AREA)
  • Medicinal Chemistry (AREA)
  • Rheumatology (AREA)
  • Rehabilitation Therapy (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Cardiology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biomedical Technology (AREA)
  • Engineering & Computer Science (AREA)
  • Vascular Medicine (AREA)
  • Dispersion Chemistry (AREA)
  • Prostheses (AREA)

Abstract

L'invention décrit un dispositif de fixation sur os pour fixer à un os un élément prothétique extensible renfermant un matériau fibreux, ledit dispositif comprenant un élément de fixation pouvant être ancré à un os ainsi qu'une interface pour fixer l'élément élastique, caractérisée par le fait que ladite interface est munie d'un organe venant s'appuyer contre l'élément élastique, ledit organe comprenant un corps solide susceptible d'être serré par l'élément de fixation, de telle sorte que le matériau fibreux est capturé entre ledit corps et l'élément de fixation. De préférence, l'élément de fixation et le corps solide interagissent de telle sorte que le matériau fibreux est réparti uniformément autour du corps solide. De préférence, le matériau fibreux comporte une gaine dans laquelle le corps solide se place en cours d'utilisation. La présente invention décrit également un élément élastique prothétique de ligament comportant un hydrogel précontraint ainsi qu'un matériau fibreux non dégradable. Ledit matériau fibreux est présent au moins à l'une des extrémités de l'élément élastique et l'hydrogel a la forme d'une tige qui se dilate pour empêcher le matériau fibreux de s'affaisser en direction de l'axe longitudinal de l'élément sous une charge physiologique.
PCT/GB1995/000836 1994-04-12 1995-04-12 Prothese de ligament croise WO1995027449A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU22190/95A AU2219095A (en) 1994-04-12 1995-04-12 Cruciate ligament prosthesis
GB9620916A GB2302029B (en) 1994-04-12 1995-04-12 Cruciate ligament prosthesis
EP95915247A EP0749292A1 (fr) 1994-04-12 1995-04-12 Prothese de ligament croise

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9407237A GB9407237D0 (en) 1994-04-12 1994-04-12 Cruciate ligament prosthesis
GB9407237.8 1994-04-12

Publications (1)

Publication Number Publication Date
WO1995027449A1 true WO1995027449A1 (fr) 1995-10-19

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1995/000836 WO1995027449A1 (fr) 1994-04-12 1995-04-12 Prothese de ligament croise

Country Status (4)

Country Link
EP (1) EP0749292A1 (fr)
AU (1) AU2219095A (fr)
GB (2) GB9407237D0 (fr)
WO (1) WO1995027449A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1871306A2 (fr) * 2005-04-01 2008-01-02 The Regents of the University of Colorado Dispositif et procede de fixation de greffe
WO2010134943A1 (fr) * 2009-05-22 2010-11-25 Soft Tissue Regeneration, Inc. Échafaudage mécaniquement compétent pour régénération de ligament et de tendon
US9433489B2 (en) 2013-03-12 2016-09-06 Soft Tissue Regeneration, Inc. Absorbable synthetic braided matrix for breast reconstruction and hernia repair
US9757132B2 (en) 2010-03-24 2017-09-12 Biorez, Inc. Mechanically competent scaffold for rotator cuff and tendon augmentation

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2513284A1 (de) * 1974-03-29 1975-10-09 Ceskoslovenska Akademie Ved Sehnenprothese und verfahren zu ihrer herstellung
FR2586927A1 (fr) * 1985-09-06 1987-03-13 Bristol Myers Co Ensemble de rattachement d'un ligament de prothese
EP0232049A1 (fr) * 1986-01-24 1987-08-12 Pfizer Hospital Products Group, Inc. Accessoire de fixation pour un ligament ou tendon prothétique
FR2636835A1 (fr) * 1988-09-23 1990-03-30 Cremascoli Spa G Ligament artificiel a fixation integree pour la liaison d'articulations osseuses
EP0454599A1 (fr) * 1990-04-25 1991-10-30 Aesculap-Icp Prothèse ligamentaire et procédé de fabrication
FR2678823A1 (fr) * 1991-07-11 1993-01-15 Legrand Jean Jacques Dispositif de renforcement d'un ligament au cours d'une plastie ligamentaire.

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2513284A1 (de) * 1974-03-29 1975-10-09 Ceskoslovenska Akademie Ved Sehnenprothese und verfahren zu ihrer herstellung
FR2586927A1 (fr) * 1985-09-06 1987-03-13 Bristol Myers Co Ensemble de rattachement d'un ligament de prothese
EP0232049A1 (fr) * 1986-01-24 1987-08-12 Pfizer Hospital Products Group, Inc. Accessoire de fixation pour un ligament ou tendon prothétique
FR2636835A1 (fr) * 1988-09-23 1990-03-30 Cremascoli Spa G Ligament artificiel a fixation integree pour la liaison d'articulations osseuses
EP0454599A1 (fr) * 1990-04-25 1991-10-30 Aesculap-Icp Prothèse ligamentaire et procédé de fabrication
FR2678823A1 (fr) * 1991-07-11 1993-01-15 Legrand Jean Jacques Dispositif de renforcement d'un ligament au cours d'une plastie ligamentaire.

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1871306A2 (fr) * 2005-04-01 2008-01-02 The Regents of the University of Colorado Dispositif et procede de fixation de greffe
EP1871306A4 (fr) * 2005-04-01 2012-03-21 Univ Colorado Dispositif et procede de fixation de greffe
WO2010134943A1 (fr) * 2009-05-22 2010-11-25 Soft Tissue Regeneration, Inc. Échafaudage mécaniquement compétent pour régénération de ligament et de tendon
US8486143B2 (en) 2009-05-22 2013-07-16 Soft Tissue Regeneration, Inc. Mechanically competent scaffold for ligament and tendon regeneration
AU2009346396B2 (en) * 2009-05-22 2013-12-19 Biorez, Inc. Mechanically competent scaffold for ligament and tendon regeneration
US8758437B2 (en) 2009-05-22 2014-06-24 Soft Tissue Regeneration, Inc. Mechanically competent scaffold for ligament and tendon regeneration
US9757132B2 (en) 2010-03-24 2017-09-12 Biorez, Inc. Mechanically competent scaffold for rotator cuff and tendon augmentation
US9433489B2 (en) 2013-03-12 2016-09-06 Soft Tissue Regeneration, Inc. Absorbable synthetic braided matrix for breast reconstruction and hernia repair

Also Published As

Publication number Publication date
AU2219095A (en) 1995-10-30
GB9620916D0 (en) 1996-11-27
EP0749292A1 (fr) 1996-12-27
GB2302029A (en) 1997-01-08
GB2302029B (en) 1997-12-03
GB9407237D0 (en) 1994-06-08

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