FR2838633A1 - Complete knee prosthesis has articulating axis connecting femoral element to tibial element moved back on horizontal level by 5 mm from center of two spherical portions to obtain higher inflection amplitude - Google Patents
Complete knee prosthesis has articulating axis connecting femoral element to tibial element moved back on horizontal level by 5 mm from center of two spherical portions to obtain higher inflection amplitude Download PDFInfo
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- FR2838633A1 FR2838633A1 FR0204892A FR0204892A FR2838633A1 FR 2838633 A1 FR2838633 A1 FR 2838633A1 FR 0204892 A FR0204892 A FR 0204892A FR 0204892 A FR0204892 A FR 0204892A FR 2838633 A1 FR2838633 A1 FR 2838633A1
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- 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
- A61F2/30—Joints
- A61F2/38—Joints for elbows or knees
- A61F2/3836—Special connection between upper and lower leg, e.g. constrained
- A61F2/384—Special connection between upper and lower leg, e.g. constrained hinged, i.e. with transverse axle restricting the movement
- A61F2/3845—Special connection between upper and lower leg, e.g. constrained hinged, i.e. with transverse axle restricting the movement allowing only for single rotation
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- Orthopedic Medicine & Surgery (AREA)
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- Oral & Maxillofacial Surgery (AREA)
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- Heart & Thoracic Surgery (AREA)
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Abstract
Description
la prothese.the prosthesis.
- 1 1 Plusieurs points meritent d'etre consideres avant de concevoir, de fabriquer, et d'implanter une prothese. Apres avoir decouvert le mode de fonctionnement de ['articulation du genou, base sur des principes de - 1 1 Several points deserve to be considered before designing, manufacturing, and implanting a prosthesis. After having discovered the operating mode of the knee joint, based on principles of
physique et de mecanique incontournables. essential physics and mechanics.
S (page Internet: http://genoux.free.fr) il apparat qu'il est possible de reproduire fidelement le mouvement de flexion extension du genou avec une prothese a axe unique et fixe, mais que certains criteres doivent etre observes et respectes pour ameliorer le fonctionnement et la fiabilite de la prothese. J'ai deja presente trots criteres (certificat d'utilite n 9805005.) Je me suds attarde plus tard sur d'autres facteurs pouvant ameliorer le S (web page: http://genoux.free.fr) it appears that it is possible to faithfully reproduce the knee extension flexion movement with a prosthesis with a single and fixed axis, but that certain criteria must be observed and respected to improve the functioning and reliability of the prosthesis. I have already presented three criteria (certificate of usefulness n 9805005.) I will focus later on other factors that can improve the
bon fonctionnement d'une prothese, et surtout sa fiabilite. proper functioning of a prosthesis, and above all its reliability.
La presente invention concerne toute prothese totale du genou a axe unique et fixe, mais egalement la prothese de hanche sur un point tres important. The present invention relates to any total knee prosthesis with a single and fixed axis, but also the hip prosthesis on a very important point.
Je reprends les trots criteres deja presentes. I repeat the trot criteria already presented.
- 1 - Positionnement precis de l'axe d'articulation. - 1 - Precise positioning of the articulation axis.
- 2 - Suppression du moment d'inertie engendre par ['angle tibia femur (angle de valgus) durant le mouvement (marche, course) Cette action dans le but essentiel d'eviter les contraintes en rotation dans un sens puis dans l'autre a chaque pas; contraintes alternatives et repetitives qui finissent par provoquer descellements et autres ennuis d'usures supplementaires. -3- Positionnement precis de la trochlee par rapport a la rotule, done a ['insertion du ligament rotulien, afin que la pression exercee par la rotule se repartisse de fa,con harmonieuse sur les deux faces de la trochlee artifcielle, car un desequilibre entrane automatiquement des contraintes nefastes, entre autre en rotation, pouvant provoquer a l' extreme une - 2 - Suppression of the moment of inertia generated by the 'tibia femur angle (angle of valgus) during movement (walking, running) This action with the essential aim of avoiding rotational stresses in one direction then in the other with each step; alternative and repetitive stresses which eventually cause loosening and other wear problems. -3- Precise positioning of the trochlea relative to the patella, thus to the insertion of the patellar ligament, so that the pressure exerted by the patella is distributed in a harmonious manner on both sides of the artificial trochlea, because an imbalance automatically causes harmful stresses, including rotation, which can cause extreme
luxation de la rotule.dislocation of the patella.
- 2 1 Avant d'aller plus loin je dois presenter la base du principe de fonctionnement de ['articulation du genou que j'ai decouvert: - Planche 1 / 5 fig. 1 -Sur chaque condyle j'ai isole deux zones caracteristiques - En position arriere un arc de cercle de 1 a 2 de rayon R qui represente la bande de glissement du condyle. La ligne reliant le centre de la bande de glissement de chaque condyle donne l' axe d' articulation - 2 1 Before going further I must present the basis of the operating principle of the knee joint that I discovered: - Plate 1/5 fig. 1 - On each condyle I isolate two characteristic zones - In the rear position an arc of a circle of 1 to 2 of radius R which represents the sliding strip of the condyle. The line connecting the center of the sliding strip of each condyle gives the axis of articulation.
unique et fixe.unique and fixed.
- En position avant basse de 2 a 3 une zone legerement bombee - In the lower front position from 2 to 3, a slightly rounded area
servant au blocage de ['extension.used to block the extension.
Senles les zones arrieres de glissement de 1 a 2 servent au mouvement de flexion extension. Des que commence la flexion les zones 2 a 3 se liberent automatiquement de l'appui qu'elles possedent sur chaque menisque. (en tirets sur la fgure.) -Figure 2. Le condyle interne, genou gauche, en position sur son menisque. Les menisques (elements femelles.) Sont les sieges des condyles (elements males) Principe de fonctionnement du genou, page Internet: http: //genoux.free.fr Pour un bien etre certain, il est indispensable que la prothese puisse produire une flexion minimum de 140 afin que la personne puisse s'accroupir sans probleme, done que l'arriere de la cuisse puisse venir en appoi sur le mollet. Position qu'il faut obtenir sans contrainte sur les elements de la prothese en fin de flexion. Il serait bon d'avoir une tolerance de quelques degree supplementaires afn d'eviter toute Only the rear sliding zones from 1 to 2 are used for the extension flexion movement. As soon as the flexion begins, zones 2 to 3 are automatically released from the support they have on each meniscus. (in dashes on the figure.) -Figure 2. The internal condyle, left knee, in position on its meniscus. The menisci (female elements.) Are the seats of the condyles (male elements) Functioning principle of the knee, Internet page: http: //genoux.free.fr For a certain well-being, it is essential that the prosthesis can produce a flexion minimum of 140 so that the person can squat without problem, so that the back of the thigh can come into contact with the calf. Position which must be obtained without constraint on the elements of the prosthesis at the end of bending. It would be good to have a tolerance of a few additional degrees in order to avoid any
mauvaise surprise.bad surprise.
Le mouvement de flexion et le mouvement d'extension vent a The flexion movement and the wind extension movement a
considerer sous deux aspects Planche 2 / 5 fg. 3. consider two aspects Plate 2/5 fg. 3.
- 3 1 1) EN CHARGE, c'est a dire en position debout, la flexion est directement tributaire du quadriceps (muscles avants de la cuisse) qui - 3 1 1) IN LOAD, that is to say when standing, the flexion is directly dependent on the quadriceps (front thigh muscles) which
intervient pour contrbler l'inertie du corps qui descend. intervenes to control the inertia of the descending body.
Durant ['extension le quadriceps est encore pleinement sollicite pour vaincre la pesanteur 2) EN PASSIF, c'est a dire assis sur le bord d'une table jambes pendantes. Pour etendre la jambe en extension complete le quadriceps est sollicite, mais pour prolonger la flexion, afin d'amener le tibia sous la cuisse, se vent les ischiojambiers qui interviennent (muscles arrieres de la cuisse) En charge durant la flexion, comme durant ['extension la puissance (F) du quadriceps est proportionnelle a la longueur du levier (L). De meme au cours de la flexion complete en passif, la puissance (-f-) des ischiojambiers est proportionnelle au bras de levier (-1-) Considerons l' articulation en extension complete, touj ours fig. 3 Quadriceps relache la rotule s'ecarte naturellement de la trochlee tout en s'affaissant Iegerement; Position naturelle au repos. Des que commence la flexion, ou sur contraction du quadriceps, la rotule reprend contact avec la trochlee en s'elevant legerement (tirets) La trochlee, qui se prolonge par l'echancrure inter-condylienne, se rapproche rapidement de l ' axe d' articulation dans les 90 premiers degree de flexion pour conserver un minimum correspondent au rayon moyen des surfaces de glissement des condyles (l 'externe etant legerement plus gros que l'interne.) Fig. 4 -la rotule vue de face. Fig. 5- la rotule vue de dessus avec la trochlee, senle la crete centrale penetre dans la trochlee, les parties laterales (facettes de glissement) suivent d'abord les bords de la trochlee qui se prolonge par les surfaces de blocage de ['extension (2 a 3) puis les During the extension the quadriceps is still fully used to overcome gravity 2) PASSIVE, ie sitting on the edge of a table with legs hanging. To extend the leg in full extension the quadriceps is required, but to prolong the flexion, in order to bring the tibia under the thigh, the hamstrings intervening (rear thigh muscles) In charge during flexion, as during [ extension the power (F) of the quadriceps is proportional to the length of the lever (L). In the same way during the complete bending in passive, the power (-f-) of the hamstrings is proportional to the lever arm (-1-) Let us consider the articulation in complete extension, always fig. 3 Quadriceps relaxes the patella naturally deviates from the trochlea while sagging slightly; Natural position at rest. As soon as the flexion begins, or on contraction of the quadriceps, the patella resumes contact with the trochlea by rising slightly (dashes) The trochlea, which is extended by the inter-condylar notch, rapidly approaches the axis of articulation in the first 90 degrees of flexion to keep a minimum correspond to the average radius of the sliding surfaces of the condyles (the external being slightly larger than the internal.) Fig. 4 - the ball seen from the front. Fig. 5- the patella seen from above with the trochlea, only the central crest penetrates into the trochlea, the lateral parts (sliding facets) first follow the edges of the trochlea which is extended by the blocking surfaces of the extension ( 2 to 3) then the
surfaces de glissement (1 a 2) dans leur premier quart. sliding surfaces (1 to 2) in their first quarter.
- 4 1 En extension complete quadriceps contracte c'est la partie basse de la rotule qui est en contact avec la trochlee, au cours de la flexion la zone de contact monte progressivement jusqu'en haut de la rotule (tirets gauches) La rotule suit la courbe de la trochlee et se rapproche done de l'axe d' articulation d' environ 25 a 30 mm durant les 90 premiers degree de flexion. L' angle sous lequel s'applique la puissance (F) du quadriceps par rapport au bras de levier (L) varie lui aussi d'une trentaine de degree (valeurs relatives) ce qui provoque une legere variation de puissance - 4 1 In full extension contracted quadriceps it is the lower part of the patella which is in contact with the trochlea, during flexion the contact zone rises gradually to the top of the patella (left dashes) The patella follows the curve of the trochlea and therefore approaches the axis of articulation by approximately 25 to 30 mm during the first 90 degrees of flexion. The angle under which the power (F) of the quadriceps is applied relative to the lever arm (L) also varies by around thirty degrees (relative values) which causes a slight variation in power
durant la flexion extension.during extension flexion.
Le bras de levier arriere (l) en relation avec les ischiojambiers The rear lever arm (l) in relation to the hamstrings
correspond au rayon moyen des surfaces de glissement des condyles. corresponds to the mean radius of the sliding surfaces of the condyles.
Il apparat clairement que la fonction du bras de levier arriere (l) est It is clear that the function of the rear lever arm (l) is
beaucoup moins importante que celle du bras de levier avant (L). much smaller than that of the front lever arm (L).
DANS LA CONCEPTION D'UNE PROTHESE LA LONGUEUR DU IN THE DESIGN OF A PROSTHESIS THE LENGTH OF THE
BRAS DE LEVER AVANT NE DOIT PAS ETRE NEGLIGEE. FRONT LIFTING ARM MUST NOT BE NEGLECTED.
En considerant ['articulation de profl, genou gauche, fg. 6 planche 3 / 5 on obtient naturellement 140 de flexion. (tirets) - En reculant la position de l'axe d'articulation (A1) sur un plan horizontal on augmente tres vite ['amplitude de la flexion maximale ainsi que la longueur du bras de levier avant (L); mais cela provoque un deplacement plus important de la rotule durant la flexion, et le bras de levier arriere diminue d'autant (pointilles) - En elevant l'axe d'articulation (A2) sur le plan vertical on augmente egalement la flexion sans toucher au bras de levier, mais l'espace vice entre condyles et plateau tibial augmente tres vite ( traits points) Il est tres important de donner une amplitude de flexion maximale a une prothese pour qu'en fin de flexion, en position accroupie, l'arriere de la cuisse puisse venir en appui sur le mollet avant que les elements de la prothese n'atteignent leur amplitude totale akin Considering the profl joint, left knee, fg. 6 board 3/5 we naturally obtain 140 bending. (dashes) - By moving back the position of the articulation axis (A1) on a horizontal plane, the amplitude of the maximum flexion as well as the length of the front lever arm (L) is increased very quickly; but this causes a greater displacement of the patella during bending, and the rear lever arm decreases by the same amount (dots) - By raising the articulation axis (A2) on the vertical plane, we also increase bending without touching to the lever arm, but the vice space between condyles and tibial plateau increases very quickly (dotted lines) It is very important to give a maximum amplitude of flexion to a prosthesis so that at the end of flexion, in squatting position, the back of the thigh can come to rest on the calf before the elements of the prosthesis reach their full amplitude akin
d'eviter toutes contraintes au niveau des zones d'encrages de la prothese. to avoid any constraints at the level of the anchoring zones of the prosthesis.
Afin d'obtenir une amplitude plus grande que la normale, il est interessant d'opter pour un recur de l'axe d' articulation de la prothese par In order to obtain a larger amplitude than normal, it is interesting to opt for a recur of the axis of articulation of the prosthesis by
rapport a la position naturelle, 5mm suffissent pour obtenir 15 de plus. compared to the natural position, 5mm is enough to get 15 more.
- 5 1 Planche 4/5 fig. 7. (L) augmentant, ['effort physique a produire sera moins important durant la flexion extension. Le recur plus grand de la rotule sera compense par ['element plastique fixe sur la rotule (planche /5 fig. 9 et 10) La diminution du bras de levier arriere n'aura pas une grande importance Le prof1 naturel de la courbe suivit par la rotule est ideal, seule la difference entre la joue externe de la trochlee, plus grande que l'interne, peut etre effacee (fig. 5 planche 2/5) la difference etant - 5 1 Plate 4/5 fig. 7. (L) increasing, the physical effort to be produced will be less during extension flexion. The larger recure of the patella will be compensated by the plastic element fixed on the patella (plate / 5 fig. 9 and 10) The reduction of the rear lever arm will not have a great importance The natural prof1 of the curve followed by the patella is ideal, only the difference between the external cheek of the trochlea, larger than the internal, can be erased (fig. 5 plate 2/5) the difference being
corrigee par ['element plastique ajoute a la rotule. corrected by the plastic element added to the ball joint.
Le fond de la trochlee artificielle (5) fig. 7 pourra suivre le meme profil et se prolongera selon un arc de cercle jusqu'au maximum. (centre de l'arc de cercle situe sur la mediane de la droite (6) joignant le depart de la trochlee avec le point arriere necessaire a ['amplitude maximale.) En consequence ['aspect exterieur de ['element femoral de la prothese peut, en occupant le meme volume, etre tres proche de la forme naturelle The bottom of the artificial trochlee (5) fig. 7 can follow the same profile and extend in an arc to the maximum. (center of the arc of a circle located on the median of the right (6) joining the start of the trochlea with the necessary rear point at the maximum amplitude. Consequently, the external aspect of the femoral element of the prosthesis can, occupying the same volume, be very close to the natural form
des condyles.condyles.
Planche 4/5- fig. 7 et fig. 8. L'ideal de la prothese a axe unique et fxe est. et restera du type charniere, en preferant deux elements tenon mortaises, ( 7 et 8) pour une plus grande stabilite laterale, ce qui permet, en plus, de laisser la trochlee complete sur toute la longueur de Plate 4 / 5- fig. 7 and fig. 8. The ideal of the single and fixed axis prosthesis is. and will remain of the hinge type, preferring two mortise tenon elements, (7 and 8) for greater lateral stability, which allows, in addition, to leave the complete trochlea over the entire length of
ses surfaces de glissement.its sliding surfaces.
Le blocage de ['extension pouvant se faire sur les tenons, les zones 9) pouvant etre amenagees avec un tampon souple pour absorber le contact au blocage de ['extension; Contact qu'il ne faut pas negliger car, par exemple, lorsque la cuisse s' eleve, suivit de ['extension du tibia, juste avant que le talon ne touche le sol, il peut se produire un petit choc, The blocking of the extension can be done on the tenons, the zones 9) being able to be brought up with a flexible pad to absorb the contact to the blocking of the extension; Contact which should not be neglected because, for example, when the thigh rises, followed by the extension of the tibia, just before the heel touches the ground, a small shock may occur,
un leger claquement.a slight click.
Le profil de la trochlee est a considerer aussi. L'axe fixe de la prothese interdisant toute rotation, aussi bien en actif quand passif, le profil peut prendre divers formes, mais la encore, le profl en (V) fig. 8 semble ideal, assurant un positionnement parfait durant la flexion extension. La largeur du ( V), comme sa profondeur, est a determiner en se souvenant que les ailerons naturels vent supprimes, et qu'en extension complete, quadriceps relache, la rotule avance naturellement en s'affaissant The profile of the trochlee should also be considered. The fixed axis of the prosthesis prohibits any rotation, both active and passive, the profile can take various forms, but again, the profile in (V) fig. 8 seems ideal, ensuring perfect positioning during extension flexion. The width of the (V), like its depth, is to be determined by remembering that the natural fins are removed, and that when fully extended, quadriceps released, the patella naturally advances as it sags
legerement d'environ 1 cm.slightly about 1 cm.
- 6 1 Le sommet de la crete plastique doit touj ours rester dans le (V) de la trochlee. Cet element plastique (10)- fg. 9 et fg. 10 planche 5/5 doit recouvrir l'essentielle de la surface arriere de la rotule (crete, facettes de glissement) surtout la totalite de sa hauteur, car il ne faut pas oublier que la zone de frottement se deplace sur toute la hauteur. Les deux extremites (haute et basse) etant arrondies. L'element plastique est une seconde surface de glissement adaptee au profl de la trochlee artifcielle qui doit rester parallele sur le plan vertical au profl naturel de la rotule et conserver la meme hauteur. L'ideal est de produire la face d'appui avant de ['element plastique a l'empreinte des facettes de glissement de la rotule. -Analysons les contraintes au niveau de l'emmanchement du tenon - 6 1 The top of the plastic ridge must always remain in the (V) of the trochlea. This plastic element (10) - fg. 9 and fg. 10 board 5/5 must cover most of the rear surface of the patella (ridge, sliding facets), especially the whole of its height, because it should not be forgotten that the friction zone moves over the entire height. The two ends (upper and lower) being rounded. The plastic element is a second sliding surface adapted to the profl of the artificial trochlea which must remain parallel on the vertical plane to the natural profl of the patella and keep the same height. The ideal is to produce the front bearing face of the plastic element in the imprint of the sliding facets of the patella. -Let us analyze the constraints at the level of the post fitting
dans le canal medullaire fg. 9 planche 5/5 (femur en coupe). in the medullary canal fg. 9 board 5/5 (femur in section).
En position assise, ['angle femur- tibia correspond a plus ou moins , que se passe-toil lorsque la personne se met debout ? la plupart du temps elle prend appui sur les deux jambes, la masse du corps se trouve alors repartie plus ou moins equitablement sur celles-ci. Le poids sur chaque jambe peut s'exercer indirectement a un niveau different sur le femur, selon que le corps soit plus ou moins penche en avant (inertie du corps, recherche de l'equilibre) Le but de cette image est de montrer ce qui se passe au niveau du tenon scelle, quelque soit la methode, dans le canal medullaire, et qui agit alors comme un simple levier sur certaines zones du canal medullaire En se relevant d'une position assise la puissance (F) du quadriceps intervient simultanement avec le mouvement de bascule du corps en avant (positionnement du centre de gravite) ce qui provoque une tres forte pression sur la zone (11) a la jonction de la coupe femorale avec la When seated, does the femuribib angle correspond more or less to what happens when the person stands up? most of the time it rests on the two legs, the mass of the body is then distributed more or less equitably on these. The weight on each leg can be exerted indirectly at a different level on the femur, depending on whether the body is more or less leaning forward (inertia of the body, search for balance) The purpose of this image is to show what occurs at the level of the sealed post, whatever the method, in the medullary canal, and which then acts as a simple lever on certain areas of the medullary canal By rising from a seated position the power (F) of the quadriceps intervenes simultaneously with the rocking movement of the body forward (positioning of the center of gravity) which causes very strong pressure on the area (11) at the junction of the femoral section with the
prothese. Pression qui se decompose en deux. prosthesis. Pressure that breaks down into two.
Sans entrer dans le detail, il appara^t que ['element femoral de la prothese, qui se prolonge par un tenon scelle dans le canal medullaire, Without going into detail, it appears that the femoral element of the prosthesis, which is extended by a post sealed in the medullary canal,
agit comme un simple levier sur le bout du femur. acts as a simple lever on the tip of the femur.
- 7 1 L'appui ( A) se produisant au niveau de la zone ( 12) extremite du tenon, la resistance ( R) s'exerce a ['inverse a la jonction femur prothese sur la zone ( 11).Cette derriere zone apparat beaucoup plus fragile que la zone d'appui, et ce, quelque soit la forme du tenon; Le profil en croix permettant une meilleure repartition des contraintes qu'une simple tige (fig. 11) et ce aussi bien sur le plan anteroposterieur qu'en rotation. Si on ajoute a la masse du corps l'inertie d'une detente plus ou moins brutale, ou l'amortissement d'un petit saut, d'un simple ecart provoque par un desequilibre Les conkaintes sur les zones d'appui et de resistance s'amplifent enormement! D'ou que provienne la puissance ( P): saute, elevation du corps par detente brutale, elevation brutale des jambes fiechis, comme cela se produit au passage d'une bosse en ski (ce n'est qu'une image)... La contrainte sur la section du femur peut engendrer L'ECLATEMENT DU CANAL M[EDULLAIRE. Dans les cas enumeres, c'est la zone (11) cote trochlee qui cedera Le phenomene peut etre inverse. Choc sur ['element femoral, par exemple sur elevation du genou qui heurte un obstacle, la puissance (P) change de place, appui (A) et resistance (R) aussi, et c'est la zone arriere - 7 1 The support (A) occurring at the level of the zone (12) end of the post, the resistance (R) is exerted at the reverse of the femur prosthesis junction on the zone (11). appears much more fragile than the support zone, regardless of the shape of the post; The cross profile allows a better distribution of stresses than a simple rod (fig. 11) and this both on the anteroposterior plane and in rotation. If we add to the mass of the body the inertia of a more or less brutal relaxation, or the damping of a small jump, of a simple deviation caused by an imbalance The conkaintes on the areas of support and resistance grow enormously! Where does the power come from (P): jump, elevation of the body by brutal relaxation, brutal elevation of the torn legs, as happens with the passage of a bump in skiing (this is only an image). The constraint on the section of the femur can lead to the bursting of the M channel. In the cases listed, it is the area (11) trochleaved side which will yield The phenomenon can be reversed. Shock on the femoral element, for example on elevation of the knee which strikes an obstacle, the power (P) changes place, support (A) and resistance (R) also, and it is the rear zone
(13) qui cedera. Cette analyse rapide, pour soulianer ['importance. (13) who will yield. This quick analysis, to underline the importance.
voire la necessite d'assurer une securite au niveau de la coupe femoral qui vient en appai sur la prothese; Une collerette a l'empreinte exterieure de la coupe du femur, solidaire de l' clement even the need to ensure security at the level of the femoral cut which comes into contact with the prosthesis; A collar with the external imprint of the femur cup, integral with the element
femoral, qui emprisonnera.it celle ci serait ['ideal. femoral, who will imprison. this one would be ideal.
La zone avant (11) est la plus sollicitee, done au moins proteger cette zone par le prolongement (14) de la prothese dans la zone arriere du femur qui n'est que le prolongement de l'echancrure inter condylienne (present aussi fg. 7) Cette portion de collerette solidaire de la prothese absorberait sa part de conkainte engendree sur la zone (11) a condition qu'au montage cette languette soit appliquee au femur, il est done preferable d'en faire autant a ['avant, portion de collerette (15). Ces deux portions de collerette (14) et (15) permettant un meilleur positionnement de ['element femoral. Avec des cotes precises, un leger pincement de la coupe femoral entre ces deux portions de collerette The front area (11) is the most stressed, therefore at least protect this area by the extension (14) of the prosthesis in the rear area of the femur which is only the extension of the inter condylar notch (present also fg. 7) This portion of the collar integral with the prosthesis would absorb its share of conkainte generated on the area (11) provided that when mounting this tab is applied to the femur, it is therefore preferable to do the same at the front, portion flange (15). These two flange portions (14) and (15) allowing better positioning of the femoral element. With precise dimensions, a slight pinch of the femoral cut between these two portions of collar
pourrait se faire, celles- ci pourraient alors remplir pleinement leur role. could be done, they could then fully fulfill their role.
(Forme et position fgl 1 coupe AA).(Shape and position fgl 1 section AA).
- 8 1 Apres cette analyse, la necessite d'obtenir une grande amplitude de flexion apparat clairement, car en s'accroupissant, si ['element femoral de la prothese vient en butee sur ['element tibial avant que la cuisse ne s'appui sur le mollet, la contrainte engendree sur la coupe femoral par S l'effet levier du tenon de la prothese sera grande.L'appui ( A) passant a ['oppose de la zone (12), la resistance ( R) se produira sur la zone (14), la puissance P ( puissance correspondent logiquement a la moitie du poids du corps, mais pouvant aller jusqu'au poids total de celui ci a ['instant ou le blocage se produit sur la prothese, sans oublier l'inertie du mouvement.) s'appliquant alors sur la longueur totale du femur peut provoquer des degats! Concernant l'effet de levier du tenon de ['element tibial, les risques vent beaucoup moins importants, pour ne pas dire inexistants. La position naturelle du tibia est essentiellement verticale; En position accroupie il ne depasse pas les 45 avant, de plus le plateau tibial est simplement surface conservant a la tete du tibia toute son efficacite. fig. 7 et 8 planche - 8 1 After this analysis, the need to obtain a large amplitude of flexion appears clearly, because by squatting down, if the femoral element of the prosthesis abuts on the tibial element before the thigh rests on the calf, the stress generated on the femoral cut by S the lever effect of the prosthesis post will be great. The support (A) passing opposite the zone (12), the resistance (R) will occur on the zone (14), the power P (power logically correspond to half the weight of the body, but which can go up to the total weight of the latter at the moment when the blockage occurs on the prosthesis, without forgetting the inertia of the movement.) then applying to the total length of the femur can cause damage! Regarding the leverage of the post of the tibial element, the risks are much less significant, not to say nonexistent. The natural position of the tibia is essentially vertical; In the squatting position it does not exceed 45 before, moreover the tibial plateau is simply surface retaining at the head of the tibia all its effectiveness. Fig. 7 and 8 board
4/S tenon en position.4 / S post in position.
L' application de ces mesures de securite est valable pour toutes les protheses dont l'immobilisation se fait par tenon; Je nense surtout a la prothese de hanche (figl2). De nombreux accidents se vent deja produit et se produiront encore, car l'emmanchement du tenon dans le canal medullaire fait office de coin! Il est indispensable pour cette prothese de posseder une surface d'appui (16) recevant la coupe femorale, c'est a dire la zone de rupture du col du femur qui aura ete surfacee, et une collerette qui emprisonne la peripherie de la coupe (base du col du femur) quelques millimetres suffsent pour eviter l'eclatement du femur. La aussi on peut ne considerer que la zone (1 7) la plus sollicitee que l' on protegerait par une portion de collerette (18) a ['oppose; celle ci repartirait le poids du corps ainsi que les contraintes supplementaires engendrees par le mouvement, d'une fa,con beaucoup plus harmonieuse sur la tete du femur a condition, la aussi, qu'au montage (scellement de la prothese) la portion de collerette (18) soit mise en contact avec la base du col, si diffcultes, prevoir une autre portion a ['oppose pour assurer le positionnement correct. 1 A plus forte raison que le poids du corps ne s'exerce pas directement dans l'axe du canal medullaire, le phenomene de levier du tenon dans le canal medullaire se produit la aussi (poids du corps sur longueur du col) Donc effet coin, plus effet de levier qutils faut neutraliser! Le poids du corps compte pour l'essentiel mais il s'ajoutent toujours des contraintes supplementaires: inertie du mouvement, charges diverges, The application of these security measures is valid for all prostheses whose immobilization is done by tenon; I am mainly concerned with the hip prosthesis (figl2). Many accidents are already happening and will happen again, because the fitting of the post in the medullary canal acts as a wedge! It is essential for this prosthesis to have a bearing surface (16) receiving the femoral cut, that is to say the zone of rupture of the neck of the femur which will have been surface, and a flange which traps the periphery of the cut ( base of femur neck) a few millimeters are enough to prevent the femur from bursting. Here too, we can only consider the most stressed area (1 7) which would be protected by a portion of collar (18) opposite it; this one would distribute the weight of the body as well as the additional stresses generated by the movement, in a way, much more harmonious con on the head of the femur provided, there also, that with assembly (sealing of the prosthesis) the portion of collar (18) is brought into contact with the base of the neck, if diffcult, provide another opposite portion to ensure correct positioning. 1 A fortiori that the weight of the body is not exerted directly in the axis of the medullary canal, the phenomenon of leverage of the post in the medullary canal also occurs there (body weight over length of the neck) So wedge effect , more leverage that must be neutralized! Body weight is essential, but there are always additional constraints: inertia of movement, divergent loads,
desequilibre a rattraper.....imbalance to catch up .....
Enfn, le bras de manivelle engendre par la longueur du col du femur sous l' action des flechisseurs et des extenseurs engendre a son tour des contraintes en rotation alternatives et repetitives pouvant etre nefastes au scellement. L'adjonction d'un ou deux petite pies (19) sous la surface d'appui et en peripherie de celle ci peut facilement contrer ces effete qui vent d'autant plus faibles que la personne est agee Finally, the crank arm generated by the length of the femur neck under the action of flexors and extensors in turn generates alternative and repetitive rotational stresses that can be detrimental to sealing. The addition of one or two small magpies (19) under the support surface and on the periphery thereof can easily counter these effects which are all the weaker as the person is older.
BEN SUR POUR APPLIQUER DE FACON RATIONNELLE CES BEN ON TO APPLY RATIONALLY THESE
SECURITES IL EST INDISPENSABLE D'EMPLOYER LA C F A O. SECURITIES IT IS ESSENTIAL TO USE C F A O.
(conception et fabrication assistees par ordinateur.) I1 faut savoir ce que l'on veut! (computer-aided design and manufacturing.) You have to know what you want!
- 2838633- 2838633
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FR0204892A FR2838633B1 (en) | 2002-04-17 | 2002-04-17 | TOTAL KNEE PROSTHESIS WITH SINGLE AXIS AND FIXED AT FLEXION AMPLITUDE GREATER THAN NATURAL AMPLITUDE |
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Application Number | Priority Date | Filing Date | Title |
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FR0204892A FR2838633B1 (en) | 2002-04-17 | 2002-04-17 | TOTAL KNEE PROSTHESIS WITH SINGLE AXIS AND FIXED AT FLEXION AMPLITUDE GREATER THAN NATURAL AMPLITUDE |
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Publication Number | Publication Date |
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FR2838633A1 true FR2838633A1 (en) | 2003-10-24 |
FR2838633B1 FR2838633B1 (en) | 2005-01-21 |
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FR0204892A Expired - Fee Related FR2838633B1 (en) | 2002-04-17 | 2002-04-17 | TOTAL KNEE PROSTHESIS WITH SINGLE AXIS AND FIXED AT FLEXION AMPLITUDE GREATER THAN NATURAL AMPLITUDE |
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4358859A (en) * | 1979-10-04 | 1982-11-16 | Schurman David J | Articulated prosthetic knee and method for implanting same |
DE4223373A1 (en) * | 1992-07-16 | 1994-01-20 | Krupp Medizintechnik | Endoprosthesis shaft for knee joint - is blade shaped for anchoring purposes and has profile preventing rotation and blade-shaped vanes |
FR2777453A1 (en) * | 1998-04-20 | 1999-10-22 | Andre Raoult | Complete knee prosthesis |
-
2002
- 2002-04-17 FR FR0204892A patent/FR2838633B1/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4358859A (en) * | 1979-10-04 | 1982-11-16 | Schurman David J | Articulated prosthetic knee and method for implanting same |
DE4223373A1 (en) * | 1992-07-16 | 1994-01-20 | Krupp Medizintechnik | Endoprosthesis shaft for knee joint - is blade shaped for anchoring purposes and has profile preventing rotation and blade-shaped vanes |
FR2777453A1 (en) * | 1998-04-20 | 1999-10-22 | Andre Raoult | Complete knee prosthesis |
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FR2838633B1 (en) | 2005-01-21 |
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