WO1994009723A1 - Improvements to the femoral component of knee prostheses - Google Patents

Improvements to the femoral component of knee prostheses Download PDF

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Publication number
WO1994009723A1
WO1994009723A1 PCT/FR1993/001052 FR9301052W WO9409723A1 WO 1994009723 A1 WO1994009723 A1 WO 1994009723A1 FR 9301052 W FR9301052 W FR 9301052W WO 9409723 A1 WO9409723 A1 WO 9409723A1
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Prior art keywords
prosthesis
knee
femoral component
posterior
femoral
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PCT/FR1993/001052
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French (fr)
Inventor
Jacques-Philippe Laboureau
Gilles Voydeville
Original Assignee
Laboureau Jacques Philippe
Gilles Voydeville
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Publication date
Application filed by Laboureau Jacques Philippe, Gilles Voydeville filed Critical Laboureau Jacques Philippe
Publication of WO1994009723A1 publication Critical patent/WO1994009723A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/16Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans
    • A61B17/17Guides or aligning means for drills, mills, pins or wires
    • A61B17/1714Guides or aligning means for drills, mills, pins or wires for applying tendons or ligaments
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS 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
    • A61F2/00Filters 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
    • A61F2/02Prostheses implantable into the body
    • A61F2/30Joints
    • A61F2/38Joints for elbows or knees
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/16Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans
    • A61B17/17Guides or aligning means for drills, mills, pins or wires
    • A61B17/1739Guides or aligning means for drills, mills, pins or wires specially adapted for particular parts of the body
    • A61B17/1764Guides or aligning means for drills, mills, pins or wires specially adapted for particular parts of the body for the knee

Definitions

  • the present invention relates to an improvement to the femoral component of knee prostheses, applying both to total prostheses and to unicompartmental femoro-tibial prostheses.
  • the properties of a normal, healthy knee are mobility and stability. Mobility is ensured by the relative movement of the femoral and tibial sliding surfaces.
  • the tibial sliding surfaces, called tibial plates are relatively flat and allow mobility in all sectors: rolling, sliding, rotation along the vertical axis of the member.
  • Stability is provided by a complex ligament system, the main components of which are formed by the anterior and posterior cruciate ligaments. It is the play of these ligaments which allows, in addition to stability, the harmonious movements which associate rolling, sliding and rotation. If, due to the disappearance of the cruciate ligaments, the movements cease to be harmonious, there occurs, as in all mechanical parts in contact, abnormal friction resulting in rapid wear of the aforementioned surfaces, this wear of course being accompanied by loss of functional stability of the knee.
  • the "constrained" prostheses include tibial plates whose concave shape is fairly exactly adapted to the convexity of the femoral component; in this technique, the contact surfaces are therefore congruent and there can therefore be no slip of the femoral component on the tibial component.
  • the knee is stable but it is not very mobile.
  • the flexions of the knee generate tangential forces on the tibial plateau, thus contributing to the loosening of the latter.
  • this association will allow the knee to rotate the tibia relative to the femur, thus better adapting the foot to the ground providing the subject with much greater mobility; such rotation capacities, while preserving good stability of the knee thanks to the conservation of the crusaders, require that the femoro-patellar compartment can constantly adapt during the rotation of the tibia under the femur; however, to avoid painful trauma and in any case abnormally high stresses, the patella must be able to disengage with good mobility, that is to say that the prosthetic femoro-patellar joint is an unguided joint, which obviously the femoro-patellar components in the form of rails or the like do not achieve.
  • the femoro-patellar segment is composed of a toric surface, regularly concave with raised external slope, of radius equivalent to that of the patellar element; in this way, the tibia can freely operate all of its rotational movements relative to its axis, the stability of the knee then being perfectly ensured by the cruciate ligaments, which it is therefore essential to preserve or reconstitute if necessary.
  • the present invention therefore aims to ensure, in a total or unicompartmental knee prosthesis, the best functioning of the ligament system formed by the anterior and posterior cruciate ligaments by placing:
  • the knee prosthesis according to the invention is thus characterized in that the condylar part of the prosthetic femoral component is constituted by a monocentric bearing whose rolling surface is cylindrical along an angular sector extending over 130 ° from the posterior part of said condyles, the axis of this cylindrical bearing passing exactly through the isometric point d implantation of natural cruciate ligaments or, in the case of prosthetic restoration, artificial cruciate ligaments.
  • the radius of the cylinder of 130 ° generating the sliding surface of the condyles of the prosthetic femoral component will preferably be between 16 and 24 mm, from the smallest size to the largest size of the prosthesis.
  • FIG. 1 is a sagittal sectional view of the femoro-tibial joint, showing more particularly the articular surfaces of the condyle and the tibial plateau, the knee being in extension; we have identified by L1 the length of the anterior cruciate ligament fitting into the center of the circle formed, over 130 °, by the posterior part of the condyle,
  • FIG. 2 is a view identical to that of Figure 1, the knee being in flexion; here we have identified by L2 the length of the anterior cruciate ligament,
  • FIG. 3 is a perspective view schematically showing new ancillary equipment for the placement of a prosthetic cruciate ligament under isometric conditions, usable with a femoral component of the type recommended by the present invention.
  • the total knee prosthesis of the unconstrained type, shown in the figures comprises: a prosthetic tibial component 1, with a practically flat tibial plate 2, conventionally manufactured by covering a metal base 3 with a layer of high polyethylene density, and a femoral component 4, the structure of which will now be specified in relation to the present invention.
  • the condylar part 5 of the femoral component 4, which rests in positive support on the tibial plateau 2 of the tibial component 1, is constituted by a monocentric cylindrical bearing and therefore comprises a cylindrical sliding surface whose axis 6 is located on the axis isometric of the femoral condyle concerned.
  • this cylindrical sliding surface forms a ribbon winding over approximately 130 ° along the condyle of the femoral component 4 so as to cover all of the flexion-extension movements of the knee.
  • the rolling of the external femoral condyle 5 on the tibia does not cause - unlike anterior prostheses - no variation in the length of the anterior cruciate ligament (ACL), identified by L1 on the Figure 1 (knee in extension) and by L2 in Figure 2 (knee in flexion). It is the same for the posterior cruciate ligament (LCP) which is inserted on the opposite condyle (internal condyle of the femoral component 4).
  • ACL anterior cruciate ligament
  • the radius of the cylindrical sliding surface of the condylar part 5 of the femoral component 4 thus formed must be between 16 and 24 mm.
  • the femoral component 4 is anchored to the end of the operated femur in a conventional manner by a polygonal cut 7 which is prepared prior to the fitting of said prosthesis.
  • a polygonal cut 7 which is prepared prior to the fitting of said prosthesis.
  • a template 9 the concave distal face of which fits exactly on the convex sliding surface of the condylar part 5 of one of the condyles of the femoral component 4 ;
  • this template 9 is provided at its proximal part with a gripping handle 10 and an index 11 extending in the intercondylar notch of the operated femur.
  • the index 11 laterally supports an angular drilling guide 12 pointing the center 6 of the monocentric bearing formed by the condylar part 5 of the femoral component 4, corresponding exactly to the isometric axis of said posterior condylar compartment 5.
  • a marking line 13 or its similar is finally provided on the condylar part 5 itself to serve as an angular reference for positioning the template 9, which allows to orient the axis passing through the drilling guide 12 relative to the femur.
  • the practitioner can introduce with great safety a spindle 15 for drilling a bone tunnel 14 for ligament implantation through the operated femoral condyle, said tunnel 14 emerging on the posterior surface of the femur in a conventional manner.
  • the present invention is of course not limited by the preferred example which has just been given relating to a three-compartment femoral prosthesis, but extends of course to all the embodiments of femoral prostheses for total knee prostheses which it either tri-, bi- or unicompartmental.

Abstract

Knee articulation prosthesis comprising a tibial component (1) on which rests a femoral component (4). The prosthesis is characterized in that, it includes means for preserving or restoring the anterior and posterior crossed ligaments, generators of stability of said knee, and in that the geometry of the condyle portions (5) of the femoral component (4) is such that the anterior and posterior crossed ligaments, whether they are natural or prosthetic, in the femur tibia articulation are subjected to the least stress possible during flexion-extension movements of the knee. The invention also concerns an auxiliary instrument (8) for positioning the crossed ligaments in conjunction with said prosthesis.

Description

PERFECTIONNEMENT AU COMPOSANT FEMORAL DES PROTHESES DU IMPROVEMENT OF THE FEMALE COMPONENT OF PROSTHESES
GENOUKNEE
La présente invention concerne un perfectionnement au composant fémoral des prothèses du genou, s'appliquant aussi bien aux prothèses totales qu'aux prothèses unicompartimentales fémoro-tibiales. On sait que les propriétés d'un genou normal, sain, sont la mobilité et la stabilité. La mobilité est assurée par le mouvement relatif des surfaces de glissement fémorale et tibiale. Les surfaces de glissement tibiales, dites plateaux tibiaux, sont relativement plates et permettent une mobilité dans tous les secteurs : roulement, glissement, rotation selon l'axe vertical du membre. La stabilité est assurée par un système ligamentaire complexe dont les principaux composants sont formés par les ligaments croisés antérieur et postérieur. C'est le jeu de ces ligaments qui permet, outre la stabilité, les mouvements harmonieux qui associent roulement, glissement et rotation. Si du fait de la disparition des ligaments croisés, les mouvements cessent d'être harmonieux, il se produit, comme dans toutes pièces mécaniques en contact, des frottements anormaux entraînant une usure rapide des surfaces précitées, cette usure s'accompagnant bien entendu d'une perte de la stabilité fonctionnelle du genou.The present invention relates to an improvement to the femoral component of knee prostheses, applying both to total prostheses and to unicompartmental femoro-tibial prostheses. We know that the properties of a normal, healthy knee are mobility and stability. Mobility is ensured by the relative movement of the femoral and tibial sliding surfaces. The tibial sliding surfaces, called tibial plates, are relatively flat and allow mobility in all sectors: rolling, sliding, rotation along the vertical axis of the member. Stability is provided by a complex ligament system, the main components of which are formed by the anterior and posterior cruciate ligaments. It is the play of these ligaments which allows, in addition to stability, the harmonious movements which associate rolling, sliding and rotation. If, due to the disappearance of the cruciate ligaments, the movements cease to be harmonious, there occurs, as in all mechanical parts in contact, abnormal friction resulting in rapid wear of the aforementioned surfaces, this wear of course being accompanied by loss of functional stability of the knee.
On connaît le remplacement prothétique des surfaces articulaires du genou par des prothèses à glissement - dites totales si elles reconstruisent la totalité des surfaces articulaires, ou unicompartimentales si elles ne s'adressent qu'à l'un des trois compartiments du genou -. Dans les deux cas, on distingue encore deux grands types de prothèses à glissement : les prothèses dites "non contraintes" et les prothèses dites "contraintes". a) Les prothèses "non contraintes" comportent des plateaux tibiaux prothétiques, généralement fabriqués en polyéthylène haute densité, qui reproduisent à peu près les plateaux tibiaux naturels et qui sont donc relativement plats. Ces prothèses ont le mérite de procurer une grande mobilité au genou dans tous les secteurs angulaires de son mouvement. Cependant, elles nécessitent idéalement la présence du système ligamentaire car, à défaut, le glissement anormal de la forme arrondie des condyles sur les plateaux tibiaux plats, ce glissement s'opérant sur une surface de contact forcément peu étendue, provoque une usure accélérée du polyéthylène ; on observe alors le plus souvent la formation d'une cupule d'usure dans laquelle le composant fémoral risque de se gripper, entraînant secondairement le descellement du composant tibial. Outre cela, les micro-particules formées par les débris d'usure entraînent des réactions intra- articulaires inflammatoires qui concourent également au descellement de la prothèse. b) Les prothèses "contraintes" comportent quant à elles des plateaux tibiaux dont la forme concave est assez exactement adaptée à la convexité du composant fémoral ; dans cette technique, les surfaces de contact sont donc congruentes et il ne peut en conséquence pas se produire de glissement du composant fémoral sur le composant tibial. De ce fait, le genou est stable mais il est peu mobile. En outre, comme le glissement antéro-postérieur des condyles sur le plateau tibial est évidemment restreint, les flexions du genou engendrent des forces tangentielles sur le plateau tibial, concourant ainsi au descellement de ce dernier.We know the prosthetic replacement of the articular surfaces of the knee by sliding prostheses - called total if they reconstruct all the articular surfaces, or unicompartmental if they are addressed only to one of the three compartments of the knee -. In both cases, a further distinction is made between two main types of sliding prostheses: so-called "unconstrained" prostheses and so-called "constrained" prostheses. a) "Unconstrained" prostheses include prosthetic tibial trays, generally made of high density polyethylene, which roughly reproduce natural tibial trays and which are therefore relatively flat. These prostheses have the merit of providing great knee mobility in all angular sectors of its movement. However, they ideally require the presence of the ligament system because, failing this, the abnormal sliding of the rounded shape of the condyles on the flat tibial plates, this sliding taking place over a necessarily small contact surface, causes accelerated wear of the polyethylene ; most often the formation of a wear cup is observed in which the femoral component risks seizing up, secondarily causing the tibial component to loosen. In addition to this, the micro-particles formed by the wear debris cause inflammatory intra-articular reactions which also contribute to the loosening of the prosthesis. b) The "constrained" prostheses include tibial plates whose concave shape is fairly exactly adapted to the convexity of the femoral component; in this technique, the contact surfaces are therefore congruent and there can therefore be no slip of the femoral component on the tibial component. As a result, the knee is stable but it is not very mobile. In addition, as the antero-posterior sliding of the condyles on the tibial plateau is obviously restricted, the flexions of the knee generate tangential forces on the tibial plateau, thus contributing to the loosening of the latter.
Il apparait donc que la meilleure solution en matière de prothèse totale ou unicompartimentale du genou soit représentée par une prothèse non contrainte déterminée par des plateaux tibiaux plats et l'existence d'un système ligamentaire préservé ou reconstruit, cette association [prothèse non contrainte - système ligamentaire efficace] étant la meilleure solution pour procurer au genou une fonction proche de la normale et garantir à la prothèse les meilleures conditions de longévité.It therefore appears that the best solution for total or unicompartmental knee prosthesis is represented by an unconstrained prosthesis determined by flat tibial plates and the existence of a preserved or reconstructed ligament system, this association [unconstrained prosthesis - system effective ligament] being the best solution to provide the knee with a function close to normal and guarantee the prosthesis the best conditions of longevity.
En particulier, cette association va permettre au genou des mouvements de rotation du tibia par rapport au fémur, donc une meilleure adaptation du pied au sol procurant au sujet une mobilité beaucoup plus importante ; de telles capacités de rotation, tout en préservant une bonne stabilité du genou grâce à la conservation des croisés, nécessitent que le compartiment fémoro-patellaire puisse constamment s'adapter lors de la rotation du tibia sous le fémur ; or, pour éviter des traumatismes douloureux et en tous cas des contraintes anormalement élevées, il faut que la rotule puisse se dégager avec une bonne mobilité, c'est-à-dire que l'articulation fémoro- patellaire prothétique soit une articulation non guidée, ce que ne réalisent évidemment pas les composants fémoro- patellaires en forme de rails ou analogue. Il est donc impératif que le segment fémoro-patellaire soit composé d'une surface torique, régulièrement concave à pente externe relevée, de rayon équivalent à celui de l'élément rotulien ; de la sorte, le tibia pourra librement opérer tous ses mouvements de rotation par rapport à son axe, la stabilité du genou étant alors parfaitement assurée par les ligaments croisés qu'il est par conséquent, essentiel de conserver ou de reconstituer le cas échéant.In particular, this association will allow the knee to rotate the tibia relative to the femur, thus better adapting the foot to the ground providing the subject with much greater mobility; such rotation capacities, while preserving good stability of the knee thanks to the conservation of the crusaders, require that the femoro-patellar compartment can constantly adapt during the rotation of the tibia under the femur; however, to avoid painful trauma and in any case abnormally high stresses, the patella must be able to disengage with good mobility, that is to say that the prosthetic femoro-patellar joint is an unguided joint, which obviously the femoro-patellar components in the form of rails or the like do not achieve. It is therefore imperative that the femoro-patellar segment is composed of a toric surface, regularly concave with raised external slope, of radius equivalent to that of the patellar element; in this way, the tibia can freely operate all of its rotational movements relative to its axis, the stability of the knee then being perfectly ensured by the cruciate ligaments, which it is therefore essential to preserve or reconstitute if necessary.
D'un autre côté, on sait que les ligaments croisés naturels ne varient pratiquement pas de longueur quelle que soit la position du genou : c'est ce qu'on appelle l'isométrie. Si cette isométrie n'existait pas, la mobilité complète du genou depuis la flexion complète jusqu'à l'extension complète ne pourrait pas être obtenue ou bien, si elle l'était, ce serait au prix de traumatismes répétés en raison de l'élongation anormale des ligaments. Cette notion est importante en ce qui concerne les ligaments naturels. Elle l'est encore plus en ce qui concerne les ligaments artificiels dont l'élasticité est nettement inférieure à celle des ligaments naturels et qui n'ont évidemment pas leurs facultés d'adaptation et de régénération. A cet égard, on a déjà proposé quelques solutions de prothèses du genou, mais la plupart d'entre elles préconisent des profils polycentriques des condyles comme dans la demande internationale n°92.08424, ou encore des composants fémoraux monocentriques, mais de rayons indéterminés comme dans le brevet GB-A-1.580.179 ou encore des ensembles prothétiques avec condyles monocentriques dont l'axe de rotation est centré sur les points d'insertion des ligaments collatéraux ; c'est le cas de la prothèse américaine d'Hollister décrite dans le brevet US- A-5.133.758 qui préconise en outre des condyles interne et externe de taille inégale, ce qui ne favorise pas vraiment la stabilité du genou. Aucune de ces réalisations antérieures ne préserve les ligaments croisés, à l'exception toutefois du brevet GB-A-1.580.179 qui préconise la conservation du seul croisé postérieur et sacrifie délibérément le croisé antérieur.On the other hand, we know that the natural cruciate ligaments hardly vary in length regardless of the position of the knee: this is called isometry. If this isometry did not exist, complete knee mobility from full flexion to full extension could not be achieved or, if it were, it would be at the cost of repeated trauma due to the abnormal stretching of the ligaments. This notion is important with regard to natural ligaments. It is even more so with regard to artificial ligaments whose elasticity is much lower than that of natural ligaments and which obviously do not have their faculties of adaptation and regeneration. In this regard, we have already proposed some knee prosthesis solutions, but most of them recommend polycentric profiles of the condyles as in international application No. 92.08424, or even monocentric femoral components, but of indeterminate radii as in GB-A-1,580,179 or prosthetic assemblies with monocentric condyles whose axis of rotation is centered on the insertion points of the collateral ligaments; this is the case of the American Hollister prosthesis described in patent US-A-5,133,758 which further recommends internal and external condyles of unequal size, which does not really promote the stability of the knee. None of these previous embodiments preserves the cruciate ligaments, with the exception, however, of patent GB-A-1,580,179 which recommends the conservation of the only posterior crusader and deliberately sacrifices the anterior crusader.
On a vu que de telles solutions nuisent considérablement à la stabilité du genou et limitent l'adaptation du pied au sol en limitant les rotations de tibia par rapport au fémur qui exigent la présence des ligaments croisés.It has been seen that such solutions considerably impair the stability of the knee and limit the adaptation of the foot to the ground by limiting the rotations of the tibia relative to the femur which require the presence of the cruciate ligaments.
En outre, toutes ces réalisations concernent exclusivement des prothèses totales du genou alors que la présente invention s'applique naturellement aux prothèses totales mais tout aussi bien aux prothèses unicompartimentales.In addition, all of these embodiments relate exclusively to total knee prostheses while the present invention naturally applies to total prostheses but just as well to unicompartmental prostheses.
La présente invention vise donc à assurer, dans une prothèse totale ou unicompartimentale du genou, le meilleur fonctionnement du système ligamentaire formé par les ligaments croisés antérieur et postérieur en posant :The present invention therefore aims to ensure, in a total or unicompartmental knee prosthesis, the best functioning of the ligament system formed by the anterior and posterior cruciate ligaments by placing:
- comme premier principe, la conservation ou la restauration des ligaments croisés antérieur et postérieur générateurs de la stabilité du genou et,- as a first principle, the conservation or restoration of the anterior and posterior cruciate ligaments that generate knee stability and,
- comme second principe, le choix d'une géométrie des condyles du composant fémoral prothétique conduisant à ce que les ligaments croisés, naturels ou prothétiques, ainsi présents dans l'articulation fémoro-tibiale subissent le moins de contraintes possibles lors des mouvements de flexion-extension du genou.- as a second principle, the choice of a geometry of the condyles of the prosthetic femoral component leading to the cruciate ligaments, natural or prosthetic, thus present in the femoro-tibial joint being subjected to the least possible stresses during flexion movements- knee extension.
La prothèse du genou conforme à 1'invention est ainsi caractérisée en ce que la partie condylienne du composant fémoral prothétique est constitué par un palier monocentrique dont la surface de roulement est cylindrique le long d'un secteur angulaire s'étendant sur 130° depuis la partie postérieure desdits condyles, l'axe de ce palier cylindrique passant exactement par le point isométrique d'implantation des ligaments croisés naturels ou, en cas de restauration prothétique, des ligaments croisés artificiels.The knee prosthesis according to the invention is thus characterized in that the condylar part of the prosthetic femoral component is constituted by a monocentric bearing whose rolling surface is cylindrical along an angular sector extending over 130 ° from the posterior part of said condyles, the axis of this cylindrical bearing passing exactly through the isometric point d implantation of natural cruciate ligaments or, in the case of prosthetic restoration, artificial cruciate ligaments.
De cette façon, on sait que la longueur des ligaments ne variera pas lors des mouvements de flexion- extension du genou. Cet avantage considérable de l'invention contribue de manière importante à la conservation des ligaments ou, dans le cas d'un ligament prothétique toujours plus fragile qu'un ligament naturel, à un travail sans sollicitation dudit ligament prothétique.In this way, we know that the length of the ligaments will not vary during flexion-extension movements of the knee. This considerable advantage of the invention contributes significantly to the conservation of the ligaments or, in the case of a prosthetic ligament always more fragile than a natural ligament, to work without solicitation of said prosthetic ligament.
En outre, le respect de l'isométrie du genou est assuré quelle que soit la forme que l'on donne à la face supérieure des plateaux tibiaux, la préservation des fonctions stabilisatrices du système ligamentaire rendant nettement moins importants les aspects mécaniques stabilisateurs liés à la congruence (prothèse contrainte) ou à la non-congruence (prothèse non-contrainte) desdits plateaux tibiaux avec la surface de glissement cylindrique des condyles du composant fémoral prothétique.In addition, respect for the knee isometry is ensured whatever shape is given to the upper face of the tibial plates, the preservation of the stabilizing functions of the ligament system making the mechanical stabilizing aspects much less important. congruence (constrained prosthesis) or non-congruence (unconstrained prosthesis) of said tibial plates with the cylindrical sliding surface of the condyles of the prosthetic femoral component.
Bien entendu, on disposera de diverses tailles de prothèse fémorale encadrant les dimensions anatomiques les plus courantes du genou naturel ; à cet effet, le rayon du cylindre de 130° engendrant la surface de glissement des condyles du composant fémoral prothétique sera préférentiellement compris entre 16 et 24 mm, depuis la plus petite taille jusqu'à la plus grande taille de la prothèse.Of course, there will be various sizes of femoral prosthesis framing the most common anatomical dimensions of the natural knee; for this purpose, the radius of the cylinder of 130 ° generating the sliding surface of the condyles of the prosthetic femoral component will preferably be between 16 and 24 mm, from the smallest size to the largest size of the prosthesis.
On observera par ailleurs que, du fait de la constitution du composant fémoral en rapport à un axe fémoral parfaitement déterminé, passant par le point isométrique du condyle concerné, il est avantageusement possible de réaliser un matériel ancillaire de pose des ligaments qui soit beaucoup plus simple et beaucoup plus sûr à utiliser que tous les matériels ancillaires jusqu'alors disponibles pour la pose de ligaments prothétiques. On peut ainsi réaliser une restauration quasi-parfaite des ligaments croisés, le point d'insertion fémoral pouvant être déterminé avec une grande précision ; en effet, après avoir mis en place le composant fémoral définitif, ou la prothèse d'essai, il suffit de procéder à une visée de l'axe ou du centre de la surface cylindrique, de rayon connu par construction, qui engendre la face de glissement fémoral sur le plateau tibial ; le point isométrique d'insertion peut alors être repéré exactement par tout index de forme approprié pointant ledit axe.It will also be observed that, due to the constitution of the femoral component in relation to a perfectly determined femoral axis, passing through the isometric point of the condyle concerned, it is advantageously possible to produce ancillary equipment for placing the much simpler and much safer to use than all ancillary materials previously available for the placement of prosthetic ligaments. It is thus possible to carry out an almost perfect restoration of the cruciate ligaments, the point of femoral insertion being able to be determined with great precision; indeed, after having put in place the final femoral component, or the trial prosthesis, it suffices to carry out an aiming of the axis or of the center of the cylindrical surface, of known radius by construction, which generates the face of femoral slip on the tibial plateau; the isometric point of insertion can then be identified exactly by any index of appropriate shape pointing said axis.
D'autres caractéristiques et avantages de la présente invention ressortiront mieux de la description qui va suivre d'un exemple de réalisation d'une prothèse fémorale totale donnée à titre d'exemple non limitatif en référence aux dessins annexés sur lesquels :Other characteristics and advantages of the present invention will emerge more clearly from the description which follows of an embodiment of a total femoral prosthesis given by way of nonlimiting example with reference to the appended drawings in which:
- la figure 1 est une vue en coupe sagittale de l'articulation fémoro-tibiale, montrant plus particulièrement les surfaces articulaires du condyle et du plateau tibial, le genou se trouvant en extension ; on a repéré par Ll la longueur du ligament croisé antérieur s'insérant au centre du cercle formé, sur 130 °, par la partie postérieure du condyle,- Figure 1 is a sagittal sectional view of the femoro-tibial joint, showing more particularly the articular surfaces of the condyle and the tibial plateau, the knee being in extension; we have identified by L1 the length of the anterior cruciate ligament fitting into the center of the circle formed, over 130 °, by the posterior part of the condyle,
- la figure 2 est une vue identique à celle de la figure 1, le genou se trouvant en flexion ; on a ici repéré par L2 la longueur du ligament croisé antérieur,- Figure 2 is a view identical to that of Figure 1, the knee being in flexion; here we have identified by L2 the length of the anterior cruciate ligament,
- la figure 3 est une vue en perspective montrant schématiquement un nouveau matériel ancillaire pour la pose d'un ligament croisé prothétique dans des conditions isométriques, utilisables avec un composant fémoral du type préconisé par la présente invention.- Figure 3 is a perspective view schematically showing new ancillary equipment for the placement of a prosthetic cruciate ligament under isometric conditions, usable with a femoral component of the type recommended by the present invention.
La prothèse totale du genou, du type non contrainte, représentée sur les figures comporte : un composant tibial prothétique 1, avec un plateau tibial 2 pratiquement plat, fabriqué classiquement par recouvrement d'une embase métallique 3 avec une couche de polyéthylène haute densité, et un composant fémoral 4 dont on va maintenant préciser la structure en rapport avec la présente invention.The total knee prosthesis, of the unconstrained type, shown in the figures comprises: a prosthetic tibial component 1, with a practically flat tibial plate 2, conventionally manufactured by covering a metal base 3 with a layer of high polyethylene density, and a femoral component 4, the structure of which will now be specified in relation to the present invention.
La partie condylienne 5 du composant fémoral 4, qui repose en appui positif sur le plateau tibial 2 du composant tibial 1, est constitué par un palier cylindrique monocentrique et comporte donc une surface de glissement cylindrique dont l'axe 6 est situé sur l'axe isométrique du condyle fémoral concerné. Suivant la présente invention, cette surface de glissement cylindrique forme un ruban s'enroulant sur environ 130 ° le long du condyle du composant fémoral 4 de manière à couvrir l'ensemble des mouvements de flexion-extension du genou. Par conséquent, l'isométrie du genou étant respectée, le roulement du condyle fémoral 5 externe sur le tibia ne provoque - à l'inverse des prothèses antérieures - aucune variation de la longueur du ligament croisé antérieur (LCA), repérée par Ll sur la figure 1 (genou en extension) et par L2 sur la figure 2 (genou en flexion). Il en est de même pour le ligament croisé postérieur (LCP) qui s'insère sur le condyle opposé (condyle interne du composant fémoral 4) .The condylar part 5 of the femoral component 4, which rests in positive support on the tibial plateau 2 of the tibial component 1, is constituted by a monocentric cylindrical bearing and therefore comprises a cylindrical sliding surface whose axis 6 is located on the axis isometric of the femoral condyle concerned. According to the present invention, this cylindrical sliding surface forms a ribbon winding over approximately 130 ° along the condyle of the femoral component 4 so as to cover all of the flexion-extension movements of the knee. Consequently, the knee isometry being respected, the rolling of the external femoral condyle 5 on the tibia does not cause - unlike anterior prostheses - no variation in the length of the anterior cruciate ligament (ACL), identified by L1 on the Figure 1 (knee in extension) and by L2 in Figure 2 (knee in flexion). It is the same for the posterior cruciate ligament (LCP) which is inserted on the opposite condyle (internal condyle of the femoral component 4).
Suivant une caractéristique complémentaire de l'invention, le rayon de la surface de glissement cylindrique de la partie condylienne 5 du composant fémoral 4 ainsi constitué doit être compris entre 16 et 24 mm. Par exemple, il sera avantageux de réaliser des prothèses fémorales dont le rayon nominal de la partie condylienne 5 s'étagera de 16 mm à la valeur maximale de 24 mm par sauts de 2 mm.According to an additional characteristic of the invention, the radius of the cylindrical sliding surface of the condylar part 5 of the femoral component 4 thus formed must be between 16 and 24 mm. For example, it will be advantageous to produce femoral prostheses whose nominal radius of the condylar portion 5 will range from 16 mm to the maximum value of 24 mm in jumps of 2 mm.
L'ancrage du composant fémoral 4 à l'extrémité du fémur opéré s'effectue de manière classique par une coupe polygonale 7 qui est préparée préalablement à la pose de ladite prothèse. En outre, on observera qu'étant donné que la position de l'axe isométrique est exactement déterminée par le centre 6 du cylindre représentatif de la surface de glissement condylienne du composant fémoral 4, il est tout à fait aisé de concevoir un instrument ancillaire de visée 8 tel qu'il sera maintenant décrit plus en détail en référence à la figure 3.The femoral component 4 is anchored to the end of the operated femur in a conventional manner by a polygonal cut 7 which is prepared prior to the fitting of said prosthesis. In addition, it will be observed that since the position of the isometric axis is exactly determined by the center 6 of the cylinder representative of the condylar sliding surface of the femoral component 4, it is all quite easy to design an ancillary sighting instrument 8 as will now be described in more detail with reference to FIG. 3.
Les dimensions des différentes tailles des composants fémoraux 4 étant parfaitement connues, il est en effet aisé, à partir de deux points de la surface cylindrique de glissement de cette prothèse, de pointer le centre 6 du cercle formé par la partie condylienne 5 par lequel passe l'axe isométrique du condyle concerné. Cette visée exacte du point d'insertion idéal d'un LCA prothétique (cas représenté sur la figure 3) , permet de poser ledit ligament dans les conditions anatomiques requises pour un travail isométrique dudit ligament croisé antérieur (LCA) naturel ou prothétique. L'instrument ancillaire de visée 8 donné sur la figure 3 comporte à cet effet un gabarit 9 dont la face distale concave vient exactement s'adapter sur la surface de glissement convexe de la partie condylienne 5 de l'un des condyles du composant fémoral 4 ; ce gabarit 9 est muni à sa partie proximale d'un manche de préhension 10 et d'un index 11 s'étendant dans l'échancrure intercondylienne du fémur opéré. L'index 11 supporte latéralement un guide de perçage angulaire 12 pointant le centre 6 du palier monocentrique formé par la partie condylienne 5 du composant fémoral 4, correspondant exactement à l'axe isométrique dudit compartiment condylien postérieur 5. Un trait de marquage 13 ou son analogue est enfin prévu sur la partie condylienne 5 elle- même pour servir de repère angulaire au positionnement du gabarit 9, ce qui permet de bien orienter l'axe passant par le guide de perçage 12 par rapport au fémur. De cette façon, le praticien peut introduire avec une grande sûreté une broche 15 de forage d'un tunnel osseux 14 d'implantation ligamentaire au travers du condyle fémoral opéré, ledit tunnel 14 émergeant sur la face postérieure du fémur d'une manière classique.The dimensions of the different sizes of the femoral components 4 being perfectly known, it is indeed easy, from two points on the cylindrical sliding surface of this prosthesis, to point the center 6 of the circle formed by the condylar part 5 through which passes the isometric axis of the condyle concerned. This exact aiming of the ideal insertion point of a prosthetic ACL (case represented in FIG. 3), makes it possible to place said ligament under the anatomical conditions required for isometric work of said natural or prosthetic anterior cruciate ligament (ACL). The ancillary sighting instrument 8 given in FIG. 3 comprises for this purpose a template 9 the concave distal face of which fits exactly on the convex sliding surface of the condylar part 5 of one of the condyles of the femoral component 4 ; this template 9 is provided at its proximal part with a gripping handle 10 and an index 11 extending in the intercondylar notch of the operated femur. The index 11 laterally supports an angular drilling guide 12 pointing the center 6 of the monocentric bearing formed by the condylar part 5 of the femoral component 4, corresponding exactly to the isometric axis of said posterior condylar compartment 5. A marking line 13 or its similar is finally provided on the condylar part 5 itself to serve as an angular reference for positioning the template 9, which allows to orient the axis passing through the drilling guide 12 relative to the femur. In this way, the practitioner can introduce with great safety a spindle 15 for drilling a bone tunnel 14 for ligament implantation through the operated femoral condyle, said tunnel 14 emerging on the posterior surface of the femur in a conventional manner.
On observera qu'il n'est malgré tout pas obligatoire de munir l'index 11 ou la prothèse d'essai lui correspondant d'un guide de perçage 12 destiné à fixer la direction de l'axe de perçage du tunnel osseux 14 ; le praticien aura alors toute liberté pour choisir cette direction, en étant néanmoins certain que le tunnel osseux 14 coupera le centre 6 du compartiment condylien postérieur 5.It will be observed that it is nevertheless not compulsory to provide the index 11 or the trial prosthesis corresponding to a drilling guide 12 intended to fix the direction of the drilling axis of the bone tunnel 14; the practitioner will then be free to choose this direction, being nevertheless certain that the bone tunnel 14 will cut the center 6 of the posterior condylar compartment 5.
Le présente invention n'est bien entendu pas limitée par l'exemple préférentiel qui vient d'en être donné relatif à une prothèse fémorale tricompartimentale, mais s'étend bien entendu à toutes les réalisations de prothèses fémorales pour prothèses totales du genou qu'elle soit tri-, bi- ou unicompartimentale. The present invention is of course not limited by the preferred example which has just been given relating to a three-compartment femoral prosthesis, but extends of course to all the embodiments of femoral prostheses for total knee prostheses which it either tri-, bi- or unicompartmental.

Claims

REVENDICATIONS
1 - Prothèse pour l'articulation du genou, comportant un composant tibial (1) sur lequel repose un composant fémoral (4), caractérisée d'une part, en ce qu'elle comporte des moyens pour assurer la conservation ou la restauration des ligaments croisés antérieur et postérieur, générateurs de stabilité dudit genou et, d'autre part, en ce que la géométrie de la ou des parties condyliennes (5) dudit composant fémoral (4) est telle que les ligaments croisés antérieur et postérieur, naturels ou prothétiques, ainsi présents dans l'articulation fémoro- tibiale subissent le moins de contraintes possible lors des mouvements de flexion-extension du genou. 2 - Prothèse pour l'articulation du genou selon la revendication précédente, caractérisée en ce que la partie condylienne postérieure (5) du composant fémoral (4) destiné à la restauration de l'un ou des deux condyles du fémur est constituée par un palier monocentrique dont la surface de roulement est cylindrique le long d'un secteur angulaire s'étendant sur 130° depuis la partie postérieure desdits condyles, le centre (6) de ce palier cylindrique passant exactement par les zones isométriques respectives d'implantation des ligaments croisés antérieur et postérieur naturels ou, en cas de restauration prothétique, des ligaments croisés artificiels.1 - Prosthesis for the knee joint, comprising a tibial component (1) on which rests a femoral component (4), characterized on the one hand, in that it comprises means for ensuring the conservation or restoration of the ligaments anterior and posterior cruciate muscles, generating stability of said knee and, on the other hand, in that the geometry of the condylar part (s) (5) of said femoral component (4) is such that the anterior and posterior cruciate ligaments, natural or prosthetic , thus present in the femorotibial joint undergo the least possible stress during flexion-extension movements of the knee. 2 - Prosthesis for the knee joint according to the preceding claim, characterized in that the posterior condylar part (5) of the femoral component (4) intended for the restoration of one or both condyles of the femur is constituted by a bearing monocentric whose rolling surface is cylindrical along an angular sector extending over 130 ° from the posterior part of said condyles, the center (6) of this cylindrical bearing passing exactly through the respective isometric zones of implantation of the cruciate ligaments natural anterior and posterior or, in case of prosthetic restoration, artificial cruciate ligaments.
3 - Prothèse fémorale selon la revendication précédente, caractérisée en ce que le rayon du cylindre engendrant la surface de roulement de la ou des parties condyliennes (5) du composant fémoral (4) est compris entre 16 et 24 millimètres, ce rayon croissant avec la taille de la prothèse.3 - Femoral prosthesis according to the preceding claim, characterized in that the radius of the cylinder generating the rolling surface of the condylar part or parts (5) of the femoral component (4) is between 16 and 24 millimeters, this radius increasing with the prosthesis size.
4 - Prothèse fémorale selon l'une quelconque des revendications précédentes, caractérisé en ce que la face antérieure de l'élément fémoral (4) constituant l'articulation fémoro-patellaire de la prothèse est composée d'une surface torique, régulièrement concave, à pente externe relevée, de rayon identique à celui de l'élément rotulien, excluant tout guidage forcé des mouvements dudit élément rotulien et donnant au tibia toute liberté dans ses mouvements de rotation.4 - Femoral prosthesis according to any one of the preceding claims, characterized in that the anterior face of the femoral element (4) constituting the femoro-patellar joint of the prosthesis is composed of a toric surface, regularly concave, to raised external slope, of radius identical to that of the patellar element, excluding any forced guidance of movements of said patellar element and giving the tibia complete freedom in its rotational movements.
5 - Instrument ancillaire (8) pour la pose d'un ligament croisé, antérieur ou postérieur, en association avec une prothèse pour l'articulation du genou conforme à 1'une quelconque des revendications précédentes, caractérisé en ce qu'il comporte des moyens (11, 12) pour pointer le centre (6) du palier cylindrique formé par la partie condylienne (5) de l'un des condyles du composant fémoral (4) de la prothèse, de sorte à repérer, au niveau de l'échancrure intercondylienne, la zone ou l'axe isométrique d'implantation des ligaments croisés naturels ou artificiels du condyle concerné.5 - Ancillary instrument (8) for placing a cruciate ligament, anterior or posterior, in association with a prosthesis for the knee joint according to any one of the preceding claims, characterized in that it comprises means (11, 12) to point the center (6) of the cylindrical bearing formed by the condylar part (5) of one of the condyles of the femoral component (4) of the prosthesis, so as to identify, at the level of the notch intercondylar, the isometric zone or axis of implantation of the natural or artificial cruciate ligaments of the condyle concerned.
6 - Instrument ancillaire selon la revendication précédente, caractérisé • en ce qu'il comporte un gabarit (9) dont la face distale concave vient exactement s'adapter sur la surface de roulement convexe de la partie condylienne (5) de l'un des condyles du composant fémoral (4), ledit gabarit (9) étant muni d'un manche de préhension (10) et d'un index (11) s'étendant latéralement sur le bord interne dudit gabarit (9) dans 1'échancrure intercondylienne du fémur opéré, ledit index (11) supportant un guide de perçage (12) dont la direction vient pointer le centre (6) de ladite partie condylienne (5). 6 - Ancillary instrument according to the preceding claim, characterized • in that it comprises a template (9) whose concave distal face comes exactly to fit on the convex rolling surface of the condylar part (5) of one of the condyles of the femoral component (4), said template (9) being provided with a gripping handle (10) and an index (11) extending laterally on the internal edge of said template (9) in the intercondylar notch of the operated femur, said index (11) supporting a drilling guide (12) the direction of which points to the center (6) of said condylar part (5).
PCT/FR1993/001052 1992-10-28 1993-10-27 Improvements to the femoral component of knee prostheses WO1994009723A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR92/12839 1992-10-28
FR9212839A FR2697154B1 (en) 1992-10-28 1992-10-28 Improvement to the femoral component of knee prostheses.

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7462199B2 (en) 2003-12-30 2008-12-09 Medicinelodge, Inc. Methods for mounting a tibial condylar implant
US8852195B2 (en) 2004-07-09 2014-10-07 Zimmer, Inc. Guide templates for surgical implants and related methods

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Publication number Priority date Publication date Assignee Title
US6905513B1 (en) * 2002-08-30 2005-06-14 Biomet, Inc. Knee prosthesis with graft ligaments

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Publication number Priority date Publication date Assignee Title
GB1580179A (en) * 1975-12-12 1980-11-26 Nat Res Dev Prostheses
FR2521421A1 (en) * 1982-02-18 1983-08-19 Grammont Paul TOTAL TROCHLEO-PATTELLAR KNEE PROSTHESIS
DE3706520A1 (en) * 1987-02-28 1988-09-08 Kernforschungsz Karlsruhe Method and aid for application of a substitute for the cruciate ligaments
EP0292678A1 (en) * 1987-05-29 1988-11-30 Kernforschungszentrum Karlsruhe Gmbh Tool for attaching a cruciate ligament prosthesis
FR2635679A1 (en) * 1988-09-01 1990-03-02 Legroux Philippe Double-condyle sliding prosthesis for knee joint
US5133758A (en) * 1991-09-16 1992-07-28 Research And Education Institute, Inc. Harbor-Ucla Medical Center Total knee endoprosthesis with fixed flexion-extension axis of rotation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1580179A (en) * 1975-12-12 1980-11-26 Nat Res Dev Prostheses
FR2521421A1 (en) * 1982-02-18 1983-08-19 Grammont Paul TOTAL TROCHLEO-PATTELLAR KNEE PROSTHESIS
DE3706520A1 (en) * 1987-02-28 1988-09-08 Kernforschungsz Karlsruhe Method and aid for application of a substitute for the cruciate ligaments
EP0292678A1 (en) * 1987-05-29 1988-11-30 Kernforschungszentrum Karlsruhe Gmbh Tool for attaching a cruciate ligament prosthesis
FR2635679A1 (en) * 1988-09-01 1990-03-02 Legroux Philippe Double-condyle sliding prosthesis for knee joint
US5133758A (en) * 1991-09-16 1992-07-28 Research And Education Institute, Inc. Harbor-Ucla Medical Center Total knee endoprosthesis with fixed flexion-extension axis of rotation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7462199B2 (en) 2003-12-30 2008-12-09 Medicinelodge, Inc. Methods for mounting a tibial condylar implant
US8852195B2 (en) 2004-07-09 2014-10-07 Zimmer, Inc. Guide templates for surgical implants and related methods

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FR2697154B1 (en) 1994-12-23

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