BE1010569A6 - Prosthetic system to replace the anterior crossed ligament of the knee and semi-removable modular prosthesis of the anterior crossed ligament of the knee - Google Patents

Abstract

The present invention relates to a prosthetic system to replace the anterior crossed ligament of the knee in two surgical phases, the first phase consisting of placing two non-removable osteointegrable fixation bases and the superstructures of the first phase and the second phase consisting, when the non-removable fixation bases have been osteointegrated with the bone tissue of their insertion site, of fitting a functional neoligament system replacing the anterior cross ligament of the knee, and the superstructure of the second phase; the fixation bases consist of a tibial implant (TI) on the tibia and a femoral implant (IF) on the femur, the superstructures of the first surgical phase comprising on the tibial side an implant support (PI), an external phantom (FE) and an internal phantom (FI), and comprising on the femoral side a femoral phantom (FF), the superstructures of the second surgical phase comprising, on the tibial side, the removable ligament complex (CLA) and comprising on the femoral side a locking system (SB) and the covering cap (CC).<IMAGE>

Description

       

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  Prosthetic system to replace the anterior cruciate ligament of the knee and semi-removable modular prosthesis of the anterior cruciate ligament of the knee.



   The present invention relates to a semi-removable modular prosthesis of the anterior cruciate ligament of the knee, fixed on osseointegrated anchors. The prosthesis according to the invention makes it possible to entirely replace the anterior cruciate ligament of the knee (ACL), with a standardized artificial modular ligament system, produced industrially.



   The population suffering from partial or total ACL tears is young, often athletic and their life expectancy still long. It is therefore necessary to have an artificial prosthesis of the anterior cruciate ligament of the knee which is simple to place and possibly replace, without being harmful to each reintervention for the articular structures. The prosthesis must provide knee stability close to physiological ACL, under conditions of high dynamic stress, without degradation and without joint consequences. This is the challenge taken up by the present invention. The system of the invention provides the surgeon with a total artificial ACL prosthesis to be placed in two stages and limiting hospitalizations, immobilizations and rehabilitation to their simplest expression.

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   The philosophy of the invention is to initially create a non-removable anchoring base which will later be used to install the neo-ligament complex and which cannot undergo alteration or mechanical wear. In a second surgical step, when the anchors are fixed to the bone, the neo-ligament system is placed in a few tens of minutes, under local anesthesia, then the patient can leave the clinic by walking. The anchoring system of the invention is sufficiently well studied to receive without modifications a more advanced neo-ligament system if it were to be replaced.

   In addition, the conceptualization of the system facilitates the possible placements and replacements of the neo-ligament system, by simplifying the surgical procedures and by limiting the bloody action to only cutaneous and subcutaneous tissues. Surgical procedures subsequent to the placement of the anchors exclude damage to the joint and bone tissues, which makes it possible to confine these reinterventions to outpatient hospitalization. All prosthetic parts and surgical instruments are supplied by the manufacturer in an easy-to-use kit.



   ACL artificial replacement systems which - -.
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 have been described today are widely criticized and face problems of various kinds. It would be too tedious to mention them all. For more information, I invite the reader to consult the reference work by F. H. FU, in KNEE SURGERY from Williams & Wilkins, 428 East Preston Street, Baltimore, Maryland: 21 202 USA VOL. 1 (1058 p).



   There is no known standard technique for placing an anterior cruciate ligament of the artificial knee

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 in conditions of reliability and security which is unanimous. All the proposed interventions are stopgap, with complicated assemblies, tunnels and screws which do not take into account the physiology of the bone tissue and the joint. The fixing means are more like carpentry than the anchoring means offered in other areas of modern surgery. The craze of the 80s by the development of new materials quickly gave way to skepticism in view of the complications: fraying and salting out of particles, rupture of the graft, bone embrittlement and effusions.



   In any case, we can affirm that the assemblies classically described differ little conceptually from what CORNER described in 1914 as the first artificial prosthesis to replace ACL in English-speaking literature (EM CORNER: Notes of a case of an artificial anterior cruciate ligament demonstrating the action of that ligament, Proc. R. Soc.



  Med. 1914; 7: 121.). The materials have certainly evolved and arthroscopy has proved to be a major advance, for the choice of implantation sites and the exploration of the joint cavity, but there has been no real artificial neoligament which is managed to win. This has led surgeons to resort to autografts or allografts, the behavior of which is sometimes unpredictable and reoperations complicated. These techniques are often deleterious for periarticular structures of the knee.



   Artificial ligaments are divided into three types: prostheses, scaffolds and stents.

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   The most commonly used neo-ligaments are of a large and stringy volume, of loose appearance, in order to allow a certain compliance and to favor the invasion of scar tissue, to increase the anchoring in the bone wells. Consequently, by the stresses and the interference of the neo-ligament with the internal face of the external tibial tuberosity, there is release of particles in the joint, responsible for inflammatory synovitis on foreign body. The stringy aspect also leads to invasion by inflammatory cells (giant multinucleated cells), see INDELICATO, P. A. Am. J. Sports Med. 1989; 17: 55-62.



  These stringy neoligaments act as bacterial traps and as particle liberators, causing infections, chronic inflammations and synovial enlargement DEL PIZZO, W. Palm Desert, CA, March 1990: 90-96.



   The fixation of certain neo-ligaments requires the use of single-use anchors, sometimes irrecoverable which can hinder re-operations.



   Controlling the measurement of the neoligament tension is problematic after fixation and it is difficult to repeat the operation. There is not sufficient reliability
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 of the tension applied at the time of the intervention, by loosening of the neoligament or by the impossibility of recontrolling it after fixing the anchor. The tension measured intraoperatively changes rapidly over time, by loosening of the neoligament mesh, requiring a minimum preload of 40 N, which decreases substantially in the days that follow, stabilizing around 20 N.



   Interventions using bone as a means of neo-ligament fixation, LAD technique (Ligament

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 Augmentation Device), LEEDS-KEIO technique (F. FU p.



  822 to 833) require their stabilization in a second step by the invasion of this fragment by the tunnel bone, while there is a certain tension and an inevitable loading. The success of these techniques is dependent on the immobilizations and the rehabilitation that the patient will follow with more or less happiness.



   The enlarged surgical approach to the joint is the cause of many joint pathologies: synovitis, hemarthrosis, infections, fibrosis, etc. The arthroscopic approach is the least harmful. It is necessary to touch the synovial and surrounding articular structures as little as possible.



   The use of corpse allografts does not guarantee bacterial, viral or prionian contamination.



   All these interventions require prolonged immobilizations, and a long and careful rehabilitation. Re-operations often require the patient to go through all the stages: general anesthesia, immobilization and rehabilitation. Interventions by autograft, each time hypothesize the biological capital of the patient, by removing tendons once, the other time from patellar bone accompanied by quadricipital tendon, etc.



   We have abandoned the utopia of recreating a neoligament of scar healing connective tissue from wells, by colonization of an absorbable neoligament, in favor of a standard artificial system that can be parameterized reliably and definitively. We also do not use elements of biological origin, whose behavior is often unpredictable.

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   The system proposed in our invention replaces random surgical procedures with a prosthesis that better corresponds to bone physiology and the constraints of its environment. It can be set up reliably, stable and definitively when it is placed, without the risk of subsequent voltage change. It paves the way for the first artificial prosthesis of ACL, whose reliability never equaled can be expected. This partially interchangeable prosthesis does little damage to the structures it passes through and poses little risk to the patient.



   Elements constituting the system
The prosthetic system of the invention can schematically be divided into two distinct parts, the implants which serve as anchoring and the supra-structures.



   The anchoring system described in the invention derives from studies initially carried out by Bânnemarck and others, aimed at stabilizing implant systems in the bone. (Cf. Osteo-integrated prostheses, Osteointegration in clinical practice; P. I. Branemarck, G. A. Zarb, T.



  Albrektsson. Ed. CDP Paris. ). These systems currently benefit from more than thirty years of experience, with remarkable success, at the level of the oral cavity, a highly septic environment, unlike the knee joint cavity and the sterile conditions of orthopedic surgery. Osteointegrated titanium implants are widely used and on a large scale in stomatology as an anchoring support for bridges or dental prostheses. They satisfy patients fitted with these systems, giving them back a function

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 masticatory and prosthetic stability equivalent to, or even better than, natural teeth.



   Osteointegrated implants have unequaled stability in the bone, while integrating in a certain way with its physiological dynamics. Osteointegrated titanium implants in particular, when properly loaded, stimulate bone tissue which behaves adaptively by increasing its density around the implant. This is a turnover by apposition resorption depending on the orientation of the loads.



   The implants according to the invention are capable of withstanding forces clearly greater than those exerted on the ligament, even under extreme conditions. The rigidity of the anchors and the zero coefficient of elongation of the neo-ligament which is compact means that a compliant system must be available, allowing normal flexion-extension dynamics, while ensuring knee stability. This is the role assumed by the compliant material of the damping cylinder.



   The artificial ligament systems that have been proposed to date have never responded to such conditions of physiologically dynamic stability and exploited as compact neoligament with interchangeable shock absorber.



   Generally, in orthopedic reconstruction surgery using internal joint repair prostheses using non-biological prosthetic materials, the anchoring of the prosthesis to the bone is ensured by bone screws, by friction or by a filling cement (metacrylate of methyl). These techniques inevitably lead to the death of osteocytes from the insertion site, due to thermal, chemical,

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 then mechanical by muscular action and loading. Even if initially, the prosthesis is firmly anchored in the bone, without any synthetic filling material, bone resorption appears, accelerated by the functional loading. The implant will eventually be surrounded by poorly differentiated fibrous tissue, which ultimately involves its disinsertion.

   This type of placement does not involve bone stimulation which generates an adaptive rearrangement. In the long term, this interface will become mechanically insufficient, causing uncontrolled movements (P. I. Branemarck). Similar problems arose with the needle and blade-shaped implants used as a fixed anchor base for dental bridges, for the same reasons.



   1. The anchors:
According to the invention, the anchors consist of two osteointegratable screw implants, one tibial, the other femoral, placed for life during the first surgical intervention. They are used initially, at the time of their placement, for the fixing of the temporary superstructures which do not put the implants in load. From the second surgical intervention, they serve to support the functional neo-ligamentary structures which replace the deficient ACL.



   The screw implants according to the invention are tubular and self-tapping. They are made industrially from medically pure titanium. These implants are provided with a thread over almost the entire length of their external surface. The thread allows them to be screwed into the bone at placement and increases their surface in contact with the bone. This contact surface of the screw threads increases the

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 osteointegratable surface and therefore the stability of the implant afterwards. The internal shape of the implants is simplified to the maximum and the available volumes maximized. It is designed in such a way that it cannot deteriorate by putting into operation and handling the installation and removal of the superstructures. The internal fittings allow the removable substructures to be securely fixed and functional.

   The removable parts must be able to be modified according to technological developments, without having to modify the geometry of the implants. The articular internal part of the implants allows the passage of the ligament towards the joint.



   The implants can be placed either on the left or on the right.



   In summary, if the removable parts can evolve technologically, the implants will be invariable because they cannot be removed.



   If the implants were loaded immediately after placement by the functional neoligamentous system (SNF), they would not attach to the bone. They would surround themselves with fibrosis and would disintegrate by the forces exerted. A waiting period of four months turns out to be necessary between the placement of the implants and their loading, it is the nurse. This waiting period or placing in a nurse allows healing of the bone tissue, then its attachment to the surface of the implants.

   This intimate fixation of the bone to the implants is a kind of ankylosis from the implant to the bone, it is osseointegration. Four months are necessary, to obtain a sufficiently large osseointegration so that the implants are able to support the forces exerted on the neoligament, without

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 possible disinsertion. Once the nurse is placed, the temporary superstructures are removed and the functional neo-ligament system is installed. The SNF is the removable substitute for physiological ACL. This type of anchoring according to the invention for an artificial ligament is new and original, because it allows a very stable fixation of the neo-ligament, which allows simple interchangeability thereof during the life of the patient.

   Having this fixed base makes postoperative immobilizations for the placement of the neoligament unnecessary, since nothing can move and the joint and the bone tissue have not been surgically affected.



   In order to obtain optimal osseointegration and stability of the implants, it is necessary that the primary and secondary stability are maximized. The primary stability is ensured by the threads, it is the stability at the time of placement. Secondary stability is the stability acquired by osseointegration of implants. It is increased in proportion to the increase in the surface in contact with the bone at constant density of bone tissue. The threads and the grainy surface conditions of the places without threads significantly increase the surface in contact with the bone tissue, which increases the stability of the implants in the bone. The external shape and the volumes of the implants of the invention optimize the primary and secondary stability.



   The surface conditions of the implants are conditioned by the need for anchoring and the density of the bone tissue with which they interact. The surface in contact with the bone tissue is microretentive at the level of the screw threads, and the other places to be osseointegrated will be

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 covered with titanium micro-granules. Some parts, the edges are in titanium polished in mirror, because they do not require osseointegration.



   The implants have a standard or enhanced diameter. Standard size implants must be able to be placed, without distinction, in all patients who have never had surgery at the ACL level.



  The increased diameter implants are used in the event that tunnels are on their insertion path. In the latter case, the tunnels must be taken to a larger diameter, to meet the drilling constraints imposed by osseointegration. However, the diameter should be as small as possible, because a large diameter implies a higher angular speed of the drills when drilling the wells, which increases the heating of the bone tissue, it is the main cause of failure of the 'osseointegration.



   2. Implanted superstructures (removable structures):
The implant-supported superstructures described in the invention are placed on their respective implants. They are two in number for each implant and attach to it at different times. They are used initially to keep the implant access routes and the SNF installation sites free. In a second step, the installed infrastructures include the neo-ligament and its accessories constituting the functional neo-ligament prosthesis (SNF). The superstructures are not osseointegratable.

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   The SNF includes the neoligament, the shock absorber cylinder and the locking system. It is the neo-ligament ready to function in its implants.



   The superstructures of the first surgical phase according to the invention are those of the nurse and include: "on the tibial side, the implant holder, the external phantom and the internal phantom; 'on the femoral side, the femoral phantom.



   If the implants were left as such in their fixation sites after the first surgical intervention, it would be impossible for the surgeon to access them in the second and correctly place the functional ligamentary substructures. It is therefore necessary to maintain the access routes to the implants from the bone surface to their insertion faces, as well as the articular emergencies impeccably clear of any tissue invasion. For this purpose, ghosts are placed. They are three in number and have a transitory function. They keep free the spaces and access routes of the places of insertion of the final neo-ligamentary infrastructures. After drilling the wells and placing the implants, they will - - - allow the healing of the tissues in contact with their surface.

   In addition, they fill the intra-implant dead spaces. After placing in the nurse, they are permanently deposited and replaced by the functional new ligamentous structures. The second surgery will be facilitated and is less hemorrhagic. On the tibial side, it is important to obtain perfect coaptation between the tibial implant and the shock absorber cylinder, whether the access path is

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 perfectly free and conformed to this element. The channel thus obtained in the bone tissue towards the tibial implant constitutes the junctional channel.



   The fibrosis that will have created around the ghosts during the four months of waiting, will make the pose of the ligament complex not very traumatic.



   The superstructures of the second surgical phase according to the invention comprise the elements which are fixed on and in their respective implants, after placing in the nurse. They include the neo-ligament and the elements that make it functional and ensure its sustainability.



   They include: * on the tibial side, the shock absorber cylinder fitted with its neoligament and the pretension screw; * on the femoral side, the locking system, the cover screw and the cap of the free screw.



   The functional neoligamentary suprastructure includes the suprastructure of the second surgical phase. These are the infrastructures which perpetuate the neoligamentary prosthesis and its function.



   The system proposed in the invention lays new foundations, which will make it possible to approach ACL surgery in a simpler, more reliable, more plastic and easily manageable aspect Without time.



   Here are presented some essential and advantageous characteristics of the system of the invention. e The system introduces the first interchangeable internal prosthesis under local or loco-regional anesthesia in orthopedic surgery. All the elements subject to fatigue or rupture can be replaced, without bloodily injuring the joint and the bone, in a minimum of time and with the minimum of constraints for the patient.

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   '' The removable parts of the system are liable to undergo changes, of which the patient may be the beneficiary, during any replacements that may occur, without having to touch the anchors. e The replacement of the deficient ACL which no longer fulfilled its role, with the present invention, restores almost normal kinematics and biomechanics, meeting the dynamic stability requirements of an active knee. e A precise implantation is obtained by arthroscopy, which allows the choice of the site of intra-articular emergence.

   It authorizes a control of the drilling of the wells and the placement of the implants at the chosen locations. e The system is simple to use, designed in such a way that it uses the techniques used in conventional ACL surgery. We will use standard arthroscopic equipment, and a sequential drilling, without modifying the habits of the surgeon used to this surgery. The placement of the various parts of the system and the powering up calls on well-tried surgical techniques. e The surgical placement technique is suitable
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 perfectly to standardization. The parameters to be determined in order to adapt the prosthesis of the invention to the "patient" are few and simple to determine.

   Once the parameters have been chosen and the blocking device activated, there is no longer any risk of release. The surgeon can resort to the usual knee testing, and have the patient wander in the operating room, with aseptic precautions, to ensure that he subjectively supports the applied tension and feels sufficient stability.

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     'The biocompatibility of all the materials used in the invention is perfectly demonstrated in the long term, without risks for the patient, with more than thirty years of hindsight.



   'All the elements that make up the prosthesis of the invention are standardized, which reduces the cost, facilitates placement and study. e Perfect osseointegration of the implants can be expected, by the use of medically pure titanium, by the treatment of their surfaces and the two-phase implantation. According to the invention, the surgeon will have to resort to short type hospitalizations. When placing the implants, it is necessary to hospitalize the patient for a few days. The first intervention takes place under general anesthesia, but all the following stages can take place under local or locoregional anesthesia, on an outpatient basis.

   In fact, obtaining a fixed anchoring base (the implants) after placing in the nurse, maintaining healed access paths, makes it possible to install the ligament functional superstructures on stable ground, which no longer requires re-anchor immobilization time of the newly installed prosthesis. The prosthesis of the invention is immediately functional after its placement.



   'The immobilization and rehabilitation are limited to their simplest expression after placement of the prosthesis according to the invention. They are no longer the factors that will determine the success and stability of the system, whereas they are the key to the success of current systems. a The forces exerted on the ligament are essentially axial with respect to the anchors, which is mechanically favorable for implants

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   osseointegrated. The adequately supported osteointegrated implants have a dynamic behavior which stimulates the bone favorably, increasing the bone density in its close periphery. The loading induces a reorganization of the bone by apposition-resorption depending on the loads applied.

   This is very different from the scar and reactive fibrosis caused by the artificial neoligaments of the literature, placed in the channels and fixed by screws. In the invention, the junctional bone well which goes from the surface of the tibial bone to the retentive surface of the tibial implant is healed over its entire length and is never subjected to friction or inflammatory reactions induced by the loading of the neoligament. The same goes for implants.



      The compact circular neo-ligament of the invention replaces all the other systems imagined. It is waterproof and cannot be invaded by inflammatory cells, has a smaller surface and few porosities. It is of reduced diameter, which decreases the risk of interference with the internal face of the external femoral condyle. a The joint can be summarily visited by arthroscopy (conventional 2.7 mm diameter arthroscope) through the femoral implant under local anesthesia, according to the inventiort: This trans-implant visit orifice, avoids having to resort to to more extensive anesthesia. When the first neoligament is placed, this path allows the guide wire to be recovered, which facilitates the engagement of the neoligament.

   If the neo-ligament were to rupture, or if a handling error made lose the permanent bond which must remain between the two implants, the continuity can be restored easily.

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   e Implants of increased diameter, allow to fit patients who would have been wearing other prosthetic types, or if the implants had to be removed, for one reason or the other.

   In the event of proven and irrecoverable failure of the system proposed in the invention, the conventional techniques can easily be applied, which is an additional guarantee for the patient. a The neo-ligament can be tightened and loosened many times from the locking system, without deforming it, by a simple maneuver, allowing to control the tension and the stability of the knee as many times as desired. After conventional knee testing, the surgeon can walk the patient in the operating room, to have his subjective assessment.
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  'For high-level athletes, it is possible to provide a personalized ligament and shock absorber. e Placement and replacement manipulations do not affect the integrity of the joint and bone. The incisions only concern the superficial tissues.



        The system can be implemented and applied quickly to patients, the materials used being all accepted by the Food and Drugs Administration of the USA.



   When a patient has suffered a total tear of the anterior cruciate ligament, it may be decided to place a prosthesis according to the invention. The placement procedure is carried out in two stages, the main stages of which are briefly recalled here.



   When placing the implants, the surgeon needs a conventional arthroscopy set and the surgical implant placement set. By arthroscopy, the

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 surgeon removes the remaining cruciate ligament, to properly visualize the ACL insertion sites. The surgeon must first locate the sites and the exact direction of the implantation wells and evaluate the length. To do this, he uses a classic guide for drilling channels for ACL (see F. H. FU in KNEE SURG. P. 370) on both the femoral and tibial sides.



   The drilling of the wells into which the implants are inserted is carried out using disposable drills, according to a precise protocol. The drilling is sequential, that is to say it is carried out by means of 2 to 5 drills passed successively and in an order of increasing diameter, under abundant irrigation. The emergence of drills in the joint is controlled by arthroscopy, as is the placement of fixtures. Slowly, the surgeon introduces a first transosseous guide drill. The drilling must be done under abundant irrigation and at slow speed, to avoid overheating of the bone tissue. It is the heating of bone tissue that is the main cause of non-osseointegration of implants.

   Indeed, bone tissue is a highly differentiated tissue, and warming or any untimely chemical or mechanical attack destroys the osteoblasts. If the osteoblasts necrotize, the bone tissue is replaced by poorly differentiated scar connective tissue, which does not have the capacity to anchor implants stably. The fixed anchoring of the implants is the key to the success of the proposed invention. After this first drilling, drills of increasing diameter are passed, to reach the desired diameter. The speed of rotation of the drills is from 500 to 1000 revolutions per minute. It is possible to carry out drilling in one

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 step, using a more efficient drill, which does not heat the bone. The motor intended for drilling must be provided for this purpose and have a very high torque.



   In tibial, the length of the well must be 45 mm. It enters the bone near the anterior tibial tuberosity, to enter the joint at the tibial insertion site of the ACL. The axis of penetration is 450 relative to the plane of the tibial plateau.



   In femoral, the well must have a length of 25 mm, an axis parallel and in extension to that of the tibial implant. The places of entry and exit of the femoral wells are subject to caution. It appears that the insertion in over the top is the best (SIDLES JA.; Ligament Lenght Relationship in the moving Knee J. Orthopedic Research Soc. 1988; 4,6: 593-610). The system according to the invention will make it possible to place electronic sensors in the shock-absorbing cylinder, which will make it possible to choose the site more judicious for the inta-articular emergence of the femoral implant.



   At the end of drilling, perfectly calibrated channels from the bone surface to the joint are obtained. They have the shape of the structures that will be implanted there ...



   Still under arthroscopic control, the surgeon installs the tibial implant which is supplied mounted on the implant holder and surmounted by the external phantom (IFP see below). The whole is screwed and the flush of the edge of the bevel of the implant is sought, point of the bevel in posterior. When the intra-articular emergence is correct and the primary stability sufficient, the surgeon installs the internal tibial phantom.

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   From the femoral side, the surgeon screws the implant under visual articular control until the bone is flush with the semi-cylindrical part.



   The primary stability of the implants is controlled, the joint abundantly rinsed and the internal femoral phantom is placed. The wounds are closed. The nurse begins. During the nurse, the patient has no functional neoligament and therefore no knee stability. This functional loss during nursing, corresponds to a few weeks, to the immobilization required for patients who have undergone a conventional intervention. Afterwards, the gain is substantial for the patient who will no longer have to undergo the constraints of heavy orthopedic surgery, all interventions being carried out on an outpatient basis.
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  During the second intervention, the surgeon will have to determine several important parameters that will allow the neo-ligament system to function in complete safety: Four months later, the implants are normally osseointegrated and the bone junction well surrounding the tibial external phantom is healed. The surgeon performs local anesthesia of the tissues surrounding the external approaches of the implants and reopens the scars previously made. He clears the vaults of the internal ghosts, then deposits them using a screwdriver.



  On the tibial side, the implant holder locking screw is loosened and the implant holder fixing screw unscrewed, which releases the external phantom of the tibial implant. The suprastructure of the tibial implant of the first surgical phase is removed. Surgeon introduces arthroscope through femoral implant and flushes

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 the joint of the blood that could have flowed there. The guidewire is introduced through the tibial implant and recovered by arthroscopic visualization using forceps. The guide wire is pulled through the two implants and emerges widely on either side of the two incisions.



  The ligament complex is fixed by its free screw to the guide wire on the tibial side. A traction is exerted on the guide wire on the femoral side and the neo-ligament enters the junctional tibial well, followed by the shock-absorbing cylinder. The neoligament crosses the tibial implant, the joint and the femoral implant, to emerge to the skin through the incision of the femoral tuberosity. The shock absorber cylinder is screwed carefully into the tibial implant, then an X-ray of the junction between the tibial implant and shock absorber cylinder is performed, to be certain that the shock absorber cylinder is perfectly co-adapted to the tibial implant. On the other side, the surgeon slides the blocking system along the neoligament into the femoral implant. The ellipsoidal screw is turned 900, which will secure the locking system to the femoral implant.

   At this time, the neo-ligament can always come and go in the tibial implant. A classic pretensioner is attached to the neoligament, * to measure its tension. The surgeon must first find the minimum preload (normally 20 N) based on a flexion angle of the leg (about 30). The surgeon flexes and extends the leg to see the behavior of the tension over the entire flexionextension run. The preload and load must be suitable for sufficient stability and normal range of motion. When the parameters are considered correct for the patient, the blocking system is activated. The neo-ligament is thus clamped and can no longer move in the implant

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 EMI22.1
 - - femoral. The patient can walk in the operating room and test the stability and mobility of his knee.

   If appropriate, the cover screw is placed in the femur, then a neutral or precalibrated pretension screw is installed on the arch of the tibial shock absorber cylinder. If a precalibrated pretensioning screw has to be fitted, additional checks must be carried out. The skin wounds are closed and the patient can leave the hospital by walking!
Note that the preload is normally 20 N for a bending angle of 300. The spring in the damping cylinder must be able to undergo a tension of 20 N without the slide sinking into the cylinder.



  Beyond 20 N., the slide will sink into the damping cylinder. To this end, and to prevent any return of the slide below 20 N, a pretensioning screw blocks the position by its extension.



   On the same day, or within a few days, the patient will return to normal function, with no re-education or immobilization whatsoever. Likewise during subsequent changes, no immobilization will be required.
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  .



   In order for the invention to be better understood, reference is made to the accompanying figures in which:
FIG. 1 represents an external view of the prosthesis according to the invention with the functional neoligamentary suprastructure mounted in and on its implants. It represents the prosthesis as it will be implanted in the patient and in function.

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   Figure 2 shows an axial longitudinal section of the prosthesis described in Figure 1 according to the invention. It represents the prosthesis as it will be implanted in the patient and in function.



   FIG. 3A represents an external view of the tibial implant according to the invention.



   FIG. 3B represents an axial longitudinal section of the tibial implant according to the invention.



   Figure 3C shows a cross section of the tibial implant passing through line I-1 of Figure 3B according to the invention.



   FIG. 4 represents an axial longitudinal section of the external phantom according to the invention.



   FIG. 5A represents an axial longitudinal section of the implant holder according to the invention.



   FIG. SB represents an elevation view of the head of the implant holder according to the invention.



   FIG. 6A represents an external view of the screw for fixing the implant holder according to the invention.



   FIG. 6B represents an axial longitudinal section of the screw for fixing the implant holder according to the invention.



   FIG. 6C represents an elevation view of the head of the screw for fixing the implant holder according to the invention.



   FIG. 7A represents an external view of the locking screw of the implant holder according to the invention.



   FIG. 7B represents an axial longitudinal section of the locking screw of the implant holder according to the invention.



   FIG. 8A represents an external view of the internal tibial phantom according to the invention.



   FIG. 8B represents an axial longitudinal section of the tibial internal phantom according to the invention.

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   FIG. 9 represents an axial longitudinal section of the tibial implant identical to FIG. 3B, surmounted by the IFP which brings together FIGS. 4, SA and 8B in which the internal tibial phantom is put in place according to the invention, such as 'they are left in place during the nurse.



   FIG. 10A shows according to the invention an external view of the damping cylinder, the neo-ligament of which is not entirely represented.



   FIG. 10B represents an elevation view of the roof of the damping cylinder according to the invention.



   FIG. 10C1 represents an axial longitudinal section of the damping cylinder, all the removable internal elements of which have been deposited according to the invention.



   FIG. 10C2 represents an axial longitudinal section of the damping cylinder identical to section 10C1 where the seal and the cradle have been put in their place according to the invention.
 EMI24.1
 



  FIG. 10C3 represents, according to the invention, an axial longitudinal section r of the damping cylinder identical to FIG. 10C2, where the spring and the tibial end of the neoligament have been added.



   FIG. 11A shows according to the invention the different parts crimped at the two ends of the neoligament. The neo-ligament is not entirely represented, the interruption is signified by the two zigzag lines. The neoligament is shown entirely in Figure 2.



   FIG. 11B shows according to the invention an axial longitudinal section of the guide slide on a fragment of neo-ligament represented in shaded form.

  <Desc / Clms Page number 25>

 



   FIG. 11C shows according to the invention an external view of the slide by its articular face. The neoligament not being represented.



   Figure 11D shows according to the invention an axial longitudinal section of the cradle.



   FIG. 12 shows the pretension screw in external view according to the invention.



   FIG. 13A represents an external view of the femoral implant according to the invention.



   FIG. 13B represents an axial longitudinal section of the femoral implant according to the invention.



   FIG. 13C represents an elevation view of the semi-cylindrical articular end of the femoral implant according to the invention.



   Figure 13D shows according to the invention a cross section of the femoral implant passing through line IIII.



   FIG. 14A represents an external view of the internal femoral phantom according to the invention.



   FIG. 14B represents an axial longitudinal section of the internal femoral phantom according to the invention.



   Figure 14C shows according to the invention a cross section of the shutter of the femoral phantom passing through the line III-III. '
FIG. 14D represents an external view of the femoral implant with the internal femoral phantom in place according to the invention.



   FIG. 14E represents a view in axial longitudinal section of FIG. 14D.



   Figure 15 shows an external view of the locking system, as it will be provided to the surgeon to be placed in the femoral implant. The pivot is mounted on

  <Desc / Clms Page number 26>

 the embrace, with its pin and its ellipsoidal screw in place according to the invention. The locking system is shown oriented by the face where the ellipsoidal screw is inserted in the pin.



   FIG. 16A shows according to the invention an external view of the pivot oriented by the face which presents the place of insertion of the stud for securing the pivot to the embrace.



   FIG. 16B shows according to the invention an external view of the pivot oriented by the face which presents the place of insertion of the ellipsoidal screw (hourly rotation of 900 with respect to FIG. 16A).



   FIG. 16C1 shows according to the invention an axial longitudinal section of the pivot passing through the insertion wells of the tightening key.



   FIG. 16C2 represents according to the invention an elevation view of the upper face of the pivot.



   Figure 16C3 shows according to the invention a cross section of the pivot passing through the line IV-IV of Figure 16C1.



   Figure 16 Dl, represents the pivot of Figure 16Cl, with a clockwise rotation of 900 relative to the axis
 EMI26.1
 of symmetry and with respect to the upper face.



  - Figure dz shows according to the invention an axial longitudinal section the pivot passing through the axis of symmetry of the expansion chamber of the pin.



   FIG. 17A shows according to the invention an external view of the embrace oriented by the face which has the vertical cutout.



   FIG. 17B represents according to the invention an external view of the embrace of FIG. 17A in clockwise rotation

  <Desc / Clms Page number 27>

 90 relative to the axis of symmetry and relative to the upper face.



   FIG. 17C1 represents according to the invention an axial longitudinal section of the embrace of the blocking system passing through the vertical notch.



   FIG. 17C2 represents according to the invention an elevation view from the top of the embrace of the locking system.



   FIG. 17C3 represents, according to the invention, an elevation view from the bottom of the embrace of the locking system.



   FIG. 17 D1 represents the embrace of FIG. 17C1 in clockwise rotation of 900 relative to the axis of symmetry and relative to the upper face.



   FIG. 17D1 represents according to the invention an axial longitudinal section of the embrace of the blocking system passing in front of the rotational stop leave.



   FIG. 17D2 represents according to the invention a cross section of the embrace of the blocking system passing through the line V-V of FIG. 17D1.



   Figure 18A shows according to the invention an elevational view of the pin of the locking system.



   FIG. 18B shows according to the invention an external view of the face having the notch of the pin of the locking system.



   Figure lé shows according to the invention the pin of the blocking system in section passing through the notch along the line VI-VI of Figure 18A.



   Figure 19A shows according to the invention an external view of the ellipsoidal screw oriented by its small convexity.



   Figure 19B shows according to the invention an external view of the ellipsoidal screw in clockwise rotation of 900

  <Desc / Clms Page number 28>

 with respect to the axis of symmetry in Figure 19A. The ellipsoidal screw therefore has its great convexity.



   Figure 19C shows according to the invention an elevational view from the top of the ellipsoidal screw.



   FIG. 20A represents according to the invention an axial longitudinal section of the definitive cover cap, passing through the entire length of the neo-ligament exhaust channel.



   FIG. 20B shows according to the invention an external view of the definitive cover cap of the femoral implant, the upper groove being taken in a row.



   FIG. 20C represents according to the invention an elevation view from the top of the definitive cover cap of the femoral implant.



   FIG. 21 represents the femoral implant covered with its definitive cover cap seen by the emergence face of the neoligament with the neoligament emerging through the articular face, as can be seen in the final prosthesis according to invention.



   Figure 22 shows the tibial implant and the tibial bone in axial longitudinal section. The tibial implant is located at the bottom of the junctional well, as can be seen after insertion, when the implant holder and the external phantom have been removed.



   We will describe below the elements that make up the prosthesis of the invention shown in Figure 1.



   The IT tibial implant is shown according to the invention in FIGS. 3A, 3B and 3C (FIG. 3C in cross section passing through the line I-I of FIG. 3B). Figures 1 and 2 show the tibial implant (IT) as it fits into the final prosthesis and in Figure 9

  <Desc / Clms Page number 29>

 in axial longitudinal section, mounted on the implant holder as it is left in place after the first surgical intervention. The numbers indicate the references of the corresponding figures.



   The IT tibial implant according to the invention is the fixed osteointegrated support of the suprastructures located in the tibial bone. It is located at the bottom of a junctional bone well left by the external phantom FE, after placing in the nurse. It is the fixing site by its internal screw pitch lOb, first of the fixing screw within the framework of the IFP (see below) at the first intervention, then of the screw pitch of the damping cylinder 45 from of the second intervention. It is the place of passage of the neoligament towards the distal articulation 12.



   The IT tibial implant according to the invention is tubular and piriform. It has a length of 18 to 22 mm and a diameter of 8 to 12 mm. Externally, there are three parts to it, the proximal 1, the intermediate 2, the distal 3 and two ends or faces FIT and FAT. The FIT proximal insertion face, forms the bottom of the junctional bone well, and the FAT articular face, emerges in the joint. Its internal part is hollow and divided into two parts, the proximal. wider serves as an anchor for the supra-structures and the distal, tapered serves as a passage for the obturator and the neo-ligament.



   The external proximal part 1 is 8 to 12 mm wide and 9 to 11 mm long, it has a screw thread 6, interrupted or not at regular intervals and a smooth border 5. The external screw thread 6 is located only on the widest part of the implant. The implant can also be self-tapping, by the presence at its widest part, of several taps not shown on the

  <Desc / Clms Page number 30>

 diagrams. The upper part of the external face of the implant has a smooth border 5, of mirror-polished titanium 1 to 2 mm in height and which goes all around the implant 5. The thread allows an advance in the '' bone of about 2 mm per 3600 turn



   The intermediate part 2 is semi-cylindrical. It makes the junction between the proximal part and the next part, it is between 2 and 4 mm long. It has four lateral cubicles (4a, 4b, 4c, 4d) of anti-rotational guided tissue regeneration, ovaloid, 2 to 4 mm wide, 1 mm high and 0.5 to 1 mm deep, hollowed out in the mass of this part. They are invaded by bone tissue during implantation, which prevents the implant from unscrewing during the maneuvers of placement and removal of the superstructures after osseointegration. The cubicles are shown in front 4a, in profile 4b, in longitudinal section 4c and in projection 4d.



   The distal end 3 of the IT tibial implant is tapered and tubular. It is separated from the enlarged part by the semi-cylindrical intermediate part which it extends. Its diameter is 3 to 6 mm and its length from 4 to 6 mm. its distal end 7a is bevelled at 450 in, so that it is flush evenly around the entire periphery of the tibial plateau at the insertion site of the ACL. Indeed, the axis of the channel entering the bone is located in the vicinity of the anterior tibial tuberosity and penetrates at an angle of about 450 relative to the plane of the tibial plateau, to emerge at the place of insertion of the 'ACL. The end of the IT implant should come into the joint slightly.

   By its bevel 7a, the IT tibial implant is oriented, by its point 7b which marks the part

  <Desc / Clms Page number 31>

 posterior, and the opposite 7c, marks the anterior part with respect to the subject after placement. Before drilling, the surgeon knows how to control the angle of penetration with respect to the plane of the tibial plateau, as well as the length of the bony channel, using a conventional drilling guide.



   The FIT insertion face of the tibial implant has a circumferential flat 8 of 1.5 to 2 mm in width which serves as a sinking stop for the supra-structures which are fixed to it. Central to the circumferential flat, the FIT is open and leads directly to the enlarged internal part of the implant.



   The FAT joint face of the IT tibial implant is flush with the surface of the tibial plateau. It is through it that the neoligament of the implant emerges, in the joint. During the nurse, the shutter emerges from 5 mm.



   The core of the IT tibial implant is hollow over its entire length. There are two parts to it, a wide internal proximal part 9 and a wide internal distal part 12a.



   The wide internal proximal part 9 has a diameter
 EMI31.1
 from approximately 4 to 7 mm approximately, over a length of approximately 6 to 8 mm. It has a smooth part over approximately 3 to 5 "mm in length 10a, it is the axial engagement barrel of the damping cylinder (FEAX). The axial engagement barrel is continued by an internal thread pitch of 5 mm , this is the internal fixation screw pitch OB of the IT tibial implant.



   The axial engagement cylinder of the shock cylinder is used to prevent axis deviations when placing the shock cylinder. Following the ductility of titanium, an axis deviation could alter the internal screw pitch lOb of the IT tibial implant, when screwing the elements of the

  <Desc / Clms Page number 32>

 suprastructures that attach to it, which would compromise the survival of the implant.



   At the distal end of the IT tibial implant, the hollow part is cylindrical and has the diameter of the neo-ligament (2.5 mm), to allow its passage, it is the channel of the neo-ligament 12a. Towards the joint, the channel widens 12b. This channel is mirror polished.



   Between the enlarged internal part 9 and the passageway of the neo-ligament 12a, there is a circular flat about 1 to 2 mm in width, this is the internal support flat 11 of the tibial implant. It serves as a support for the locking screw (see below).



   The internal screw pitch 10b of the tibial implant allows the attachment of two tibial superstructures at different times: 'at the screw pitch of the implant holder 19a.



     * at the thread of the shock absorber cylinder 45.



   Elements of the tibial implant superstructures:
Supra-structures of the first surgical phase:
The main roles of the structures of the first surgical stage are: * to simplify the operation of placing the tibial implant during the intervention.



     '' to keep the junctional channel free and healed.



     * to facilitate access to the insertion side of the tibial implant.



   For ease of placement in the operating room, it is necessary that the IT tibial implant, the PI implant holder and the external FE phantom are provided

  <Desc / Clms Page number 33>

 by the manufacturer in one piece is the IFP. IFP is the acronym for Implant-External Phantom-Implant Holder.



  The IFP will continue during the implantation, until the implant holder PI and the external phantom FE are deposited, when the definitive functional suprastructure is placed.



   The external phantom FE according to the invention is shown in FIG. 4 in axial longitudinal section and in FIG. 9 in axial longitudinal section, mounted on the IT tibial implant as it is left in place after the first surgical intervention. The numbers indicate the references of the corresponding figures.



   The external phantom FE according to the invention is of cylindrical and tubular shape, it has the diameter of the tibial implant and has a length of 20 to 27 mm with a thickness of 0.5 to 2.5 mm. We can describe the external face of the perfectly smooth cylinder and two ends, the proximal or external emergence Emf and the distal or implant face Fi. Its internal part is hollow over its entire length.



   The external phantom FE keeps the junctional channel free. It has the same external shape as the damping cylinder which will be placed after it. It is smooth on the surface, but has no mechanical function. The external emergence face Emf is flush with the surface of the tibial bone. It has an external bearing margin 16b looking towards the surface after placement. It serves as a support for the covering edge of the internal tibial phantom 37. The implant face Fi, which is in contact with the tibial implant, has its cibial bearing margin 16a with a width of 1.5 to 2 , 5 mm, which comes to rest on the support flat 8 of the tibial implant.

  <Desc / Clms Page number 34>

 



   The internal, tubular part is wider in its proximal section 13, and narrower (length of 5 mm) at the end 14 which attaches to the tibial implant. These two parts are separated by the internal circular support surface 15 from the external phantom which is 1 to 2 mm wide. It serves as a support for the bearing margin of the fixing screw 20.



  The narrow internal part 14 is threaded with a thread 17, which allows the insertion of the screwdriver for the removal of the external phantom after placing in the nurse.



   Inside the external phantom FE come the implant holder PI and the internal phantom FI.



   The implant holder PI according to the invention is shown in FIG. 5A in axial longitudinal section, in FIG. SB in elevation view of its head, and in axial longitudinal section, mounted on the tibial implant IT in FIG. 9 The numbers indicate the references of the corresponding figures.



   The implant holder (PI) has two screws VB, VF, fitted into each other. The external, or fixing screw VF, is used to fix the external phantom FE to the tibial implant IT (see fig. 9), the second internal to the previous one is the locking screw VB, it is used to block the screw fixing "" 'see fig. 9). The PI implant holder allows the placement of the tibial implant at its insertion site. It is necessary that the IFP can be screwed and possibly unscrewed. To prevent the VF fixation screw from unscrewing from the IT tibial implant during unscrewing operations, the VB locking screw is screwed in the previous one and blocks it.

   The fixing screw VF fully tightened in the IT tibial implant surmounted by the external phantom FE, does not touch the bottom 11 of the internal enlarged part of the IT tibial implant, while the locking screw VB the

  <Desc / Clms Page number 35>

 can, when fully tightened. There is therefore a gap between these two screws 18. This blocks the fixing screw VF, which can be screwed and unscrewed without risk of unscrewing the fixing screw of the IT tibial implant. ',. implant holder PI has on its head a nut (EVF) for the screwing and unscrewing key of the IFP in the tibial bone.



   After placing in the nurse, the PI implant holder and the external phantom FE must be removed. The surgeon first unscrews the locking screw VB by the nut which it has at its head 25, then the fixing screw VF by its nut EVF. The PI implant holder is removed, then a screwdriver is inserted into the thread 17 of the external phantom to remove it. It should be noted that the IT tibial implar does not know how to unscrew, the lateral cubicles of guided tissue regeneration prevent this movement by invasion of bone tissue and osseointegration.



   The constituent parts of the implant holder PI according to the invention are shown in FIG. 6A, where the fixing screw VF is seen in external view; in Figure 6B, where we see the fixing screw VF in axial longitudinal section, in Figure 6C, where we see the projection of the head of the implant holder PI; in FIG. 7A, where the locking screw VB of the implant holder PI is seen in external view and in FIG. 72,. where we see the locking screw VB of the implant holder PI in axial longitudinal section. FIG. 9 represents the implant holder PI in axial longitudinal section, mounted on the tibial implant IT.



   The fixing screw VF according to the invention is shown in Figures 6A, 6B and 6C and in Figure 9. The numbers indicate the references of the corresponding figures.

  <Desc / Clms Page number 36>

 



   The VF fixation screw, as described above, is one of the two constituent parts of the PI implant holder and is used to screw and unscrew the IFP when placing the IT tibial implant.



   Externally, according to the invention, it has two separate parts, the TVF head and the PVF extension, it is axially hollow. The head has an hexagonal nut EVF which allows the insertion of the screwing key and unscrewing of the IFP in the bone. The head of the fixing screw also has a circular collar 21 and a support margin 20 of 1.5 to 2.5 mm wide, which enters into coaptation on the internal circular flat 15 of the external phantom, during its fixing in the IT tibial implant surmounted by the external phantom FE. To be fixed in the IT tibial implant, the fixing screw VF has an external screw pitch 19a of the same caliber as that 10b of the tibial implant.

   Between this screw thread 19a and the bearing margin 20, there is a cylindrical extension 19b, which comes into contact with the screw thread of the external phantom 17 and fills the barrel of axial engagement of the shock-absorbing cylinder of the tibial implant. FEAX distally.



   The fixing screw is hollow axially over its entire length, to receive the locking screw therein. Its core at the level of its head is cylindrical and smooth at 22, to continue with a thread 23 which allows the fixing of the locking screw. The thread 23 continues through the channel 24 from the end of the locking screw. In the elevation view of Figure 6C, we see the nut of the fixing screw and the passageway of the CVB locking screw. The passageway for the locking screw is made up of the following parts 22, 23 and 24. When the fixing screw is fully screwed into the tibial implant

  <Desc / Clms Page number 37>

 IT, the end of the screw does not touch the bottom of the enlarged part of the tibial implant there, it is receding 18.



   The locking screw according to the invention is shown in Figures 7A in external view and 7B in axial longitudinal section. The head of the screw is shown in elevation in FIG. 5B and mounted in the IFP in FIG. 9. The numbers indicate the references of the corresponding figures.



   The VB locking screw according to the invention, as its name suggests, serves to block the VF fixing screw in the IT tibial implant. The VB locking screw is made up of two separate parts, the head and its extension.



  Axially, it is hollow.



   The head 25 of the locking screw is hexagonal in shape and is used for screwing it in and out. The head 25 of the locking screw has a smaller diameter than that of the head of the fixing screw. At its extension 29, it has a thread 26 which will be fixed in the internal thread 23 of the fixing screw VF. In axial longitudinal section fig. 7B., We see the channel 28 which transfixes the screw right through, it is used for the passage over its entire length of the shutter of the phantom - t. internal tibial. At the tibial end of the locking screw VB, there is the support area 27. This support area is circular and comes to butterfly at the level of the part 11 by screwing in the fixing screw VF, which blocks the fixing screw VF.



   The internal phantom FI is represented in FIGS. 8A in external view and 8B in axial longitudinal section. FIG. 9 represents it in axial longitudinal section as it is left in place on the IFP during the setting up.

  <Desc / Clms Page number 38>

 nurse. The numbers indicate the references of the corresponding figures.



   The internal phantom FI according to the invention, is placed in the external phantom, on the implant holder PI and is securely held in place by friction on the lower surface of the external phantom FE. It fills the internal dead space of the IFP and covers with its cover the external emergence of the external ghost Emf. The obturator extends into the implant holder and continues in the neoligament channel of the tibial implant, to emerge in the joint.



   It is formed externally from two parts, the plug 30 covered with a cover 33 and an elongated element, the shutter 31.



   The cap of the internal phantom 30 is presented as a cylinder covered with a cover 33. It is made of plastic. The cylinder is hollowed out by circular retention fins 34 of diameter slightly greater than the cylinder. They serve to keep the internal phantom FI in place by friction. The diameter of the cylinder is identical to the internal diameter of the external phantom FE.



   The cover 33 extends from 0.5 to 1 mm the diameter of the stopper zu It forms a rounded arch 36. The cover extends beyond the cylinder of the stopper by a circular margin, it is the covering edge 37 of the outer margin of the outer phantom . It comes exactly to cover the external bearing margin 16b of the external phantom whose width it has. It has in its center the emergence of the thread of a nut 35. This nut 40 is set in the mass of the phantom. It is provided with a thread 41 which makes it possible to insert the screwdriver for removing the internal phantom.

  <Desc / Clms Page number 39>

 



   The articular part of the plug 30 is located opposite the cover and is open. We see a cylindrical cavity 3 to 5 mm deep, it is the chamber 38 of the tibial internal phantom. It is circular and fits perfectly on the head of the nut of the VB locking screw. The shutter 31 of the channels is set on the ceiling 39 of this chamber. The channel shutter can be made of the same material as the plug 30. In the diagrams, it is shown in shaded for ease. The section shows the crimped removal nut 40 and its screw pitch 41.



   The shutter emerges from the center of the ceiling 39 of the room. It is tapered and engages in the PI implant holder and the central channel of the IT tibial implant, to enter the 5 mm joint. The plug 30, caps the nut of the locking screw VB, fills the dead space of the IFP until its external emergence Emf. The cover covers the outer margin 16b of the outer phantom.



   The joint end of the obturator penetrates 5 millimeters into the joint, which prevents any invasion of the joint emergence of the tibial implant. The four pieces forming the IFP, are left in
 EMI39.1
 place during the nurse, with the internal phantom rus overcoming and crossing the whole. This minimizes the number of manipulations during the IT tibial implant placement surgery.

   After the nurse, the internal phantom FI is removed, then the locking screw VB diese--. Then, the fixing screw VF is removed, authorized the removal of the external phantom, thus appears a channel them fibrous very smooth (it is the channel joins-which will allow to insert with a

  <Desc / Clms Page number 40>

 minimal bloodshed, the ligament complex in the bone.



   The external phantom FE is the last structure to be placed before closing the tibial wound.



   The advantage of this IFP assembly, overcome afterwards by the internal phantom FI is to limit the number of manipulations, but above all to never have tissue that invades the support flat 8 of the tibial implant. The shock absorber cylinder must be perfectly adapted to the implant, otherwise there is a risk of the shock absorber cylinder being unscrewed.



   Supra-structures of the second surgical phase:
The Removable Ligament Complex (CLA) according to the invention, replaces with a compact neo-ligament and a shock absorber the assemblies carried out to date to replace the ACL. The major difference compared to other systems, is that it is easy to remove and replace in the event of a problem and does not require placement of intervention on the joint. This is one of the most original features of the proposed invention.



   The total length of the tibial implant surmounted by the shock cylinder is approximately 45 mm long. The external face of the shock-absorbing cylinder therefore covers the entire length of the fibrotic junctional bony channel, which goes from the tibial bone surface to the support flat of the tibial implant 8.



   The elements of CLA:
The shock absorber cylinder according to the invention is shown in Figures 1 and 2, mounted on the implant

  <Desc / Clms Page number 41>

 tibial as in the final prosthesis and in Figures 10A, 10B, 10 Cl, 10C2 and 10 C3 individually.



  The numbers indicate the references of the corresponding figures.



   The role of the shock absorber CA is to compensate for the changes in distance between the intraarticular emergence of the implants during flexionextension movements of the knee. It imposes on the neo-ligament a sufficient tension to ensure stability, on the greatest possible angle of flexion. The tension being as close as possible to that of the physiological ACL.



  The shock absorber CA and the neo-ligament allow in short to have flexibility and functional stability of the knee. It contains the stress material. This constraint material can be of several types: spring, tensile elastic, compressive tube, etc. It must be able to maintain a voltage ensuring functional stability, close to that of the ACL. In the figures of the invention, it is the spring which has been shown.



   Externally, according to the invention, the damping cylinder has the appearance of a cylinder 20 to 30 mm long, 8 to 12 mm in diameter and 0.5 to 1 mm thick, the external surface SE of which is smooth at 42a. The external surface SE of the damping cylinder ÇA is not osseointegratable, either because it is made of mirror-polished titanium, or because it is silicone, for example. It includes at its articular end, distally, the device 43 for fixing to the tibial implant. The neoligament 44 emerges from the fixation device. Its proximal end or proximal face is flush with the tibial bone at its place of penetration into the bone.



   The proximal face of the damping cylinder 42b forms a vault 47 which is flush with the bone surface after

  <Desc / Clms Page number 42>

 placement. It comprises four wells 48 of approximately 2 mm in depth and diameter, arranged around a central hole 49. The four holes serve for the insertion of the key which screws and unscrews the cylinder of the tibial implant.



  The central hole 49 has its role described below and is used to engage and screw the prestressing screw.



   The fixing device 43 of the damping cylinder is a hollow cylinder 4 to 7 mm wide and 6 to 8 mm long which continues proximally in the main cylinder. It consists of two parts, the screw thread 45 and the filling stump 46 of the axial engagement cylinder of the IT tibial implant. The thread 45 to 5 to 6 mm long and 4 to 7 mm in diameter, separated from the main cylinder by the filling stump 6 of the axial engagement cylinder which is 3 to 4 mm long and the same diameter than the previous piece. The fixing device 43 is hollowed out over its entire length, as described below.



  The thread 45 is fixed in the IT tibial implant.



   At the junction of the main cylinder 42 and the accessory cylinder 43, there is a flat portion of the damping cylinder 55.



  It has the same width as the support flat 8 of the IT tibial implant with which it comes into contact after placement.



  It is essential that. these two parts are perfectly co-adapted, to control it, the surgeon will perform a joint control Rx.



   The interior of the damping cylinder CA includes a large dead space completely closed and isolated from the surrounding environment after placement, thanks to the seal and the prestressing screw.



   The internal part of the damping cylinder is hollow and forms the CCA chamber of the damping cylinder. It is closed at its two ends, by the ceiling 51a of the

  <Desc / Clms Page number 43>

 chamber of the damping cylinder proximally which is the internal part of the arch 47 and through the bottom 51b of the internal part. The vault 47 is pierced with a central well provided with a screw pitch 49 intended to receive the prestressing screw. The bottom 51b of the internal part is flat and continues in the accessory cylinder 43. The central part is pierced with a channel from which one can distinguish two parts, the proximal and the distal. The proximal part of the channel forms the cubicle 50b of the seal. It is 3.5 to 4 wide; 5 mm by 3 to 5 mm in length and cylindrical.

   The distal part of the channel 50a allows the passage of the neoligament of the shock absorber towards the neoligamentary channel 12a of the tibial implant.



  The seal is inserted into the seal cubicle. The role of the seal is to isolate the articular cavity from the dead space of the damping cylinder, this, to prevent the passage of articular liquids in the cylinder, or of particles due to wear, from the cylinder shock absorber towards the joint. It must be wear-free and cannot deform the ligament which crosses it centrally. It should be noted that the extension of the slide 56c may possibly
 EMI43.1
 be of such a length that it extends at rest -. up to the seal.



   The cradle is shown in Figures NO 10C2 and 11D. The numbers indicate the references of the corresponding figures.



   On the bottom of the damper cylinder chamber rests the cradle 52a. It is pierced with a central channel the diameter of the neoligament or the extension of the slide 52c. The cradle receives the spring in a gutter 52b intended to immobilize it. It is completely removable. Under

  <Desc / Clms Page number 44>

 the cradle, is the seal 53a. It has the diameter of the damper cylinder chamber. It prevents axial deflection of the spring during loading.



   In the damping cylinder are two capital parts, the neo-ligament and the spring which we will describe.



   The neo-ligament is shown partially in Figures 1, 10A, 10C3 and 11A, and entirely in Figure 2. The numbers indicate the references of the corresponding figures.



   The neo-ligament proposed in the invention is quite different from those presented to date. It is a rope 130 to 150 mm long and 2 to 3 mm in diameter. Its technical characteristics are quite different from those of the neo-ligaments offered to date.



   Neigigament 57 is a cord composed of a flexible, inextensible, dense biocompatible material, 2 to 2.5 mm in diameter, circular in shape, suitable for the greatest number of patients, whatever their activity and their weight. It must be waterproof, non-porous and cross-linked in terms of its fibers. It must be able to withstand tensile forces of more than 1000 Newton and be able to undergo flexionextension movements under load, of several tens of millions of revolutions (in-vitro and in-vivo), without dropping particles and without deterioration. . One material seems to meet these standards and is accepted by the FDA, it is polytetrafluorethylene PTFE. The neo-ligament according to the invention is crimped at its two ends. The tibial end is fixed in the slide 56a of the shock absorber cylinder.

   The free end includes a crimped screw, with a diameter slightly smaller than the rope with no screw,

  <Desc / Clms Page number 45>

 
 EMI45.1
 it is the free FSC screw also shown in 49. The thread allows the fixing of the guide lines.



  It includes four sections which are distributed as follows: * the intra tibial part 57a comprises the internal section of the CLA and the tibial implant. It is about 30 mm long; * the intra-articular part 57b enters the joint by the tibial implant, to come out of it by the semi-cylindrical part of the femoral implant.



  It is 30 mm long; * the femoral intra-implant part 57c passes right through the femoral implant over 25 to 30 mm in length; '' the extra-prosthetic part 57d, emerges over a length of 4 to 5 cm in the subcutaneous tissues. when placing the prosthesis, the surgeon must configure it for the patient. To do this, he must measure the tension in the neoligament using a pretensioner which attaches to this part of the ligament, the other parts being inaccessible.



  The intra-articular segment of the neo-ligament according to the invention undergoes flexion movements and the tibial intraimplant, undergoes back and forth movements.



  The neo-ligament is crimped at both ends. a: The proximal end of the neoligament is crimped into the slide.



  The slide is shown according to the invention in Figures 2, 10C3 and 11A. The numbers indicate the references of the corresponding figures.



  The slide C according to the invention consists of a circular plate 56a provided by its articular face with a

  <Desc / Clms Page number 46>

 central extension 56c which crimps the tibial end 57a of the ligament. Its articular face is hollowed out by a circular gutter 56b outside the central extension.



  The circular gutter retains the proximal part of the spring. The proximal face of the slide 56d is flat. At rest, it abuts against the ceiling 51a of the damping cylinder chamber with a force of approximately 20 N.



   When the neo-ligament is put under tension by mobilization of the knee, the slide moves in the room by a movement of back and forth. To avoid a pumping phenomenon, during these back and forth movements of this piston, a distance 59 between the slide and the interior of the cylinder is provided. The slide can be kept lower voluntarily compared to the ceiling, by a pretensioning screw calibrated for a predetermined driving distance. The extension of the slide towards articular 56c may be of more or less length. The neoligament is fixed in the extension 56c of the slide. b: The distal end of the neo-ligament is crimped in a screw, the free screw.



   The free screw 58a is shown according to the invention
 EMI46.1
 in Figures 1, 2 and 11A. The numbers indicate the references, corresponding figures.



  At the extraprosthetic femoral end 57d of the neoligament, the free screw 58a is crimped. It is solidly crimped at the end of the neo-ligamentary cord by crimping 58b. It has a thread 58c extended by a smooth segment 58d which is used for fixing the guide wire (guide line). The guide line is used to facilitate CLA placement maneuvers.



   Role of the free screw: during the second surgical phase, after removal of the ghosts, the surgeon

  <Desc / Clms Page number 47>

 access the joint by arthroscopy through the femoral implant, to recover the guide wire introduced into the tibial implant. The guide wire is pulled outside the femoral implant. It then goes right through the joint. Its length is approximately 50 cm and has a nut at each of its ends which can receive the thread 58c of the free screw. Next, the surgeon fixes the free screw to the guide wire, and pulls the neoligament through the implants and the joint from the femoral implant. It will do the opposite if the ligament system should be removed.



   At the end of the intervention, before closing the tissues, the free screw will be encapsulated in a silicone plug (BS) and the ligament end which protrudes from the femoral implant is abandoned in the subcutaneous tissues. The silicone plug facilitates the release of the free screw during any subsequent recovery.



   The spring is embedded between the slide and the cradle.
 EMI47.1
 1 / r '
The spring according to the invention is shown in Figures 2 and 10 C3. The numbers indicate the references of the corresponding figures.



   The cushion 54. has a length of about 18 mm and is embedded between the cradle 52a of the damping cylinder and the slide 56a. The neo-ligament passes inside the spring. The spring cannot be in contact with the interior of the cylinder, nor with the neo-ligament or the extension of the slide. It is the part whose development will be the most delicate of the whole system. It must be resistant, unalterable and lend itself perfectly to its role of elastic substitute for ACL, while maintaining the tension of the neo-ligament. It restores elasticity to

  <Desc / Clms Page number 48>

 system, the viscoelasticity not being reproducible by a spring. The spring stroke is dependent on the isometric locations chosen for the articular emergences of the implants.

   Significant deviations can be noted depending on the sites of emergence of the implants on the tibial plateau and the external tuberosity of the femur. The maximum travel of the slide is approximately 10 mm, which leaves a significant margin of error, if we deviate from the ideal isometric points.



   The spring is preloaded in the shock absorber with a tension of around 20 N, which must correspond to a bending angle of 25 to 30. This preload can be increased by the pretension screw and controlled by the pretensioner.



   The seal according to the invention is shown in Figures 10C2 and 10C3 in axial longitudinal section. The numbers indicate the references of the corresponding figures.



   The seal 53 is circular and encloses the neo-ligament, which makes back and forth movements at this element. Optionally, the extension to the slide 56c can be of greater length than in the diagrams and passes through the seal.



     The prestressing s is shown according to the invention in FIG. 12. The numbers indicate the references of the corresponding figures.



   The VPC prestressing screw has a head 60a and a screw pitch 60b. The screw head has a hexagonal pitch for screwing it in and out. The thread of the damper cylinder roof allows it to be inserted. The screw pitch of the screw 60b is continued by an extension of variable length 60c. This extension can be neutral,

  <Desc / Clms Page number 49>

 if it does not push in the slide, the screw is then intended to close the chamber.



   The prestressing screw is screwed in the center of the top of the dome of the damping cylinder. It pushes the slide into the shock absorber by a preset distance, preloading the spring with a force which is proportional to the length of the extension of the screw. The surgeon will have a set of calibrated screws to impose the desired prestresses. However, if no prestressing had to be established, the screw introduced will be neutral and will serve as a shutter for the roof, to isolate the dead space of the damping cylinder from the outside.



   The femoral implant is shown according to the invention in Figures 1, 2.13A, 13B, 13C, 13D 14D, 14E and 21.



  The numbers indicate the references of the corresponding figures.



  * The IF femoral implant according to the invention is tubular.



  It attaches to or slightly above the external femoral tuberosity and emerges in the joint at the femoral insertion site of the ACL, along an axis which is approximately in a straight line with the axis of the implant. IT tibial. From many studies, it seems that the ideal way to place it is over the top. It is intended to receive within it the removable locking system of the neo-ligament.



  Removal of the blocking system opens an access route via the internal channel of the femoral implant (GIF), through the external femoral tuberosity.



   Externally, the femoral implant is 25 mm long and 7 to 11 mm in diameter. It is cylindrical over most of its length 61 and semi-cylindrical to articular 62. It is described with two ends or faces, the proximal face FEE is the external access route, and the face

  <Desc / Clms Page number 50>

 distal or articular FAF emerges in the joint. To this, we can add the internal part which forms a CIF channel which runs right through it axially.



   The cylindrical part is threaded with a thread 63 and presents towards the articulation of the taps 64 which are 2 to 4 in number. Opposite the taps is a smooth edge 65 circumferential mirror polished from 1 to 2 mm in height. The taps 64 are intended to tap the bone to form the bone thread which allows the perfect adaptation of the thread in the bone with the minimum of heating. The taps have lateral anti-rotation guided tissue regeneration boxes 66 of dimension equivalent to those of the tibial implant. These cubicles are made in the mass of metal from the lower part, on the main flat of the tap 67a. The cutting part 67b is at right angles to the main flat of the tap.



   The semi-cylindrical part 62 is truncated towards the joint, by the emergence of the anti-rotational channel of the femoral implant. The truncated part is the articular emergence face of the FAF femoral implant.



   Proximally, the femoral implant has the external emergence face'FFE which is flush with the bone surface of the external femoral tuberosity after placement. It has a border 68 0.5 to 1 mm thick over the entire circumference of the emergence face. It serves as support for the lower overflow of the internal femoral phantom 76 and with the lower face of the cover cap 128 successively.



   It is through the external emergence face, via the entrance to channel 68b, that the surgeon has access from

  <Desc / Clms Page number 51>

 the exterior to the internal part of the femoral implant and to the joint.



   This access route allows several possibilities: - it makes it possible to perform a limited arthroscopy of the joint and to rinse it; - it allows the guide wire to be recovered.



   The internal geometry of the implant is reduced to its simplest expression. Immediately upon examination, we notice two distinct parts, separated by the margin of support.



   The internal proximal, cylindrical part 71 is wide and has a gutter, the internal gutter 72 of the femoral implant, a few millimeters from the external emergence of the implant. It is 1 mm high by 0.5 to 0.8 mm deep and goes all the way around the internal part horizontally. It is used to secure the locking system to the implant (see below).



   The distal part, narrower 70, has a length of 5 mm, is truncated circular, it is the anti-rotational channel of the femoral implant. This form is anti-rotational for the embrace of the neo-ligament blocking system (see below).



   The margin 69 which delimits the widened part of the narrow part, serves to support the blocking system.



   Elements of the suprastructures of the femoral implant:
Suprastructure of the first surgical phase:
The femoral phantom according to the invention is represented in FIGS. 14A, 14B, 14C, 14D and 14E. The numbers indicate the references of the corresponding figures.



   The femoral phantom FF according to the invention is used to maintain the emergence faces and the internal part of

  <Desc / Clms Page number 52>

 the femoral implant IF free of any tissue invasion during delivery.



   Externally, it appears as a cylinder 73 which fills the enlarged part 71 of the femoral implant. It is surmounted by a cover 74 whose lateral overflow 76 serves to cover the margin 68a of the femoral implant.



  The distal end has a prominence, the obturator 75 of the internal phantom of the tibial implant which fills the narrow part 70 of the femoral implant, to emerge from 5 to 10 mm in the joint. The cover has in its center a screw for positioning and removal identical to that 40 of the internal phantom of the tibial implant. It has a thread 77 which allows the same instrument to be used as on the tibial side. It is held in the implant by retention fins 78 of diameter slightly greater than the diameter of its main cylinder, by friction.



   It is made of the same material as the tibial internal phantom and is only used during the nurse's call.



  It is used to prevent invasion of the femoral implant of any tissue during this period, after which it is permanently deposited. There will therefore be no dead space at the implant level and it will be easily accessible to surgeons. It is installed after the placement of the femoral implant, after which the wound can be closed.



     Supra-structures of the second surgical phase:
The blocking system is shown according to the invention
 EMI52.1
 in Figures 2, 15, 16A, 16B, 16C1, 16C2, 16C3, 16D1, 17A, 17B, 17C1, 17C2, 17C3, 17D1 and 17D2. The numbers indicate the references of the corresponding figures.



   The inventive blocking system is a considerable advance over bone anchoring techniques

  <Desc / Clms Page number 53>

 conventional artificial ligaments, which do not allow iterative control of the ligament tension, without risk of damaging the anchorage. Thanks to the invention, the surgeon can at will practice all the manipulations he wishes, without damaging the ligament, the blocking system and the surrounding structures. The locking system is interchangeable. It can therefore also evolve.



   The blocking system according to the invention is intended to block the neo-ligamentary cord, without modifying its vertical position in the implant or deforming it during tightening. It is composed of the fitting of the pivot on the embrace. The internal embrace envelops the rope around its entire periphery. When it is released, the neoligament can come and go freely, when it is closed, the arch of the pivot has flexed its flexible part towards the ligament which can no longer move. The blocking is effected by a rotation of 900 of the pivot on the embrace, from the position of freedom of the rope. If the pivot can rotate 900, the embrace is wedged in the anti-rotational part of the bottom of the implant. The blocking system is fixed in the implant and cannot come out during the manipulations and during the operation of the prosthesis.



  To do this, a * circular pin fixed on the pivot and prevents the system from coming out of the implant, but allows its rotation of 900 for tightening and loosening maneuvers. The pin can be neutral, allowing the placement or removal of the locking system. The pin can be activated by the ellipsoidal screw, which partially engages it in the groove of the femoral implant, preventing the blocking system from coming out of the implant. In short, it is quite simply that

  <Desc / Clms Page number 54>

 the surgeon can place and fix the blocking system, and block or release the neoligament, which can in certain circumstances save considerable time.



  To further increase the simplicity of handling, the pivot and the embrace are inseparable.



   One of the preponderant advantages of the prosthetic system of the invention is to allow the patient to test himself the compliance and the stability of his ligament, by walking or exercises during the intervention, after conventional testing. of his knee by the operator. This can lead to changes in the length and tension of the system. The ease of manipulation will save appreciable time, great flexibility in this type of manipulation and security of fixation of the neo-ligament. The surgeon can block and unblock the neo-ligament as desired, until reaching the perfect compromise of knee tension and stability.



   The locking system according to the invention is cylindrical and fits perfectly into the soul of the femoral implant. It allows the passage of the neo-ligament in its center (centric retention system). The locking system is made up of four elements: the pivot, the grip, the pin and the ellipsoidal screw. All these elements are supplied in one piece by the manufacturer.



   We will see each of the elements of the locking system according to the invention individually.



   The pivot is shown according to the invention in Figures 15,16A, 16B, 16C1, 16C2,16C3 and 16D1. The numbers indicate the references of the corresponding figures.



   The pivot P according to the invention serves to safely simplify the operation of blocking the neo-ligament in

  <Desc / Clms Page number 55>

 the femoral implant. The pivot can rotate 900 in the implant, moving the ligament from absolute freedom to total blockage. A click is perceived when the surgeon arrives at the desired 900 and when he goes to 00.



   Externally, according to the invention, the pivot is a cylinder 79 15 to 18 mm long and the diameter of the enlarged internal part of the femoral implant. The cylinder has the insertion groove of the pin 80 proximally, it is circumferential and 1 mm high and deep. The cylinder has a vertical cut in its mass, it is the insertion notch of the ellipsoidal screw 99b. This notch comprises in fact two notches distributed on either side of the expansion chamber 110 of the pin, the upper 81a where the head of the ellipsoidal screw is located and the lower 81b, for the foot of the ellipsoidal screw. . The cutout overflows on the proximal side, it is the upper access of the ellipsoidal screw 99a, through which it can be turned using a hexagonal screwdriver.

   Around mid-height, the pivot cylinder has a hole which pierces it into its core 101 for the insertion of the pivot securing stud to the embrace.
 EMI55.1
 



  The cylinder of. pivot at two ends or faces, the cy The proximal face 93 is flush with the external surface of the tibial implant and the distal face 94 which allows the insertion of the embrace.



   The proximal face (represented in FIG. 16C2 presents a central well, the neo-ligament well 95 of the pivot which pierces the pivot axially 96a as far as the chamber of the pivot. It is used for the passage of the proximal neo-ligament which emerges towards the outside at this point and continues distally through the embrace, to

  <Desc / Clms Page number 56>

 join the joint. On either side of the central well, there are two wells 97 of 2 mm in diameter and depth, they are used for the insertion of the key which allows the tightening and loosening of the locking system. Another well 98 comprising a thread, is used for fixing the screwdriver which allows the insertion and disinsertion of the blocking system, as well as the insertion of the screw which fixes the cover cap of the femoral implant.

   Opposite the well at 98, is seen the notch 99b for insertion of the empty ellipsoidal screw. Dotted is indicated the depth 100 of the gutter of the pin).



  At the place of insertion of the ellipsoidal screw, there is a recess 89 to give it room fig. 16C2.



  Between the surface of the pivot and this withdrawal, there is a larger volume, it is the expansion chamber 110 of the pin.



   The distal face 94 is open and communicates with the chamber of the pivot 96a through a wide circular opening 104. The distal face comprises a circumferential support of 0.5 to 1.2 mm thick, it is the support flat of the pivot 103. This support flat comes into intimate contact with the support flat 92 of the embrace.



   The distal face 94 is gaping, for the engagement of the embrace. The thickness of the cylinder rests on the lateral margin of the embrace and limits its engagement. The pivot is integral with the embrace, to prevent the operator from being forced to handle small diameter parts.



   The intrados of the pivot according to the invention is divided into two distinct parts, a narrow part of the diameter of the neo-ligament (the neo-ligament well 95 of the pivot) and a wider part, the chamber of the pivot 96a. The ceiling 96b

  <Desc / Clms Page number 57>

 of the pivot chamber is pierced by the neoligamentary well. The neo-ligamentary well is smooth, while the chamber has a longitudinal arch on its wall, the stopping of the pivot 102, it is it which passing from 0 to 90 of rotation will block or unblock the embrace. The internal wall of the chamber has an orifice 101 for the insertion of the fixing stud.



   A stud is pressed into the hole in the cylinder to engage the rotational gutter. It secures the pivot to the embrace, within the limits of the need for rotation.



   According to the invention, the embrace is represented in FIGS. 15,17A, 17B, 17C1, 17C2,17C3, 17D1 and 17D2. The numbers indicate the references of the corresponding figures.



   According to the invention, the embrace E is used to enclose the neo-ligament, without deforming it and without modifying the tension of the neo-ligament chosen by the surgeon. The embrace is integral with the pivot which can rotate 900 on it, but it cannot rotate in the implant, because it is blocked in the antirotation channel 70 of the femoral implant.



   Its shape is relatively complex, to respond to the reduced space in which it is located and the loads to which it will be subjected. It identifies the neo-ligament on the largest possible perimeter. It retains the neoligament in the femoral implant at a desired length and preload tension, as well as during the overloads which inevitably occur, without possible relaxation of the neoligament.



   The embrace is machined from a single metal cylinder and is traversed right through axially by the neo-ligament.

  <Desc / Clms Page number 58>

 



     1, the embrace is presented as a tube of three successive thicknesses, hollowed axially by a channel 105 which passes right through it, the diameter of the neo-ligament. The three thicknesses divide it into three parts, the proximal, the middle and the distal.



   The proximal or constrained portion 82 encloses the neoligament and is inserted into the chamber 96a of the pivot. The stress can be schematically divided into two parts by a plane passing axially through the vertical cutout 87, the fixed part PF and the flexible part PM.



  The fixed part PF continues in the intermediate part 83, it is therefore integral with the intermediate part. The flexible part is dissociated from the intermediate part by a horizontal cut 86 flush with the latter over 170 to 1800 and a vertical cut over the entire length 87, from 5 to 100 in width. The flexible part is presented as a semi-circular flag secured to the fixed part. These two cuts allow the flexible part to bend, to enclose the neo-ligament.



   Externally, at the level of the proximal part, one notices on its external face of the fixed part a gutter, the gutter 88 of rotational guide of
 EMI58.1
 .... the embrace on the pivot. The joining stud is fixed in the hole of the pivot 101 and emerges in the gutter of the embrace. This device secures the embrace to the pivot, while allowing the rotation of the pivot. The length of the gutter allows a rotation of 900, without the pivot can be removed. The flexible part has on the 900 before the vertical and horizontal cutting, over its entire axial length a rectangular range, the sliding range of the edge of the pivot 85a.

   At 90 from the vertical cutout 87 is the leave

  <Desc / Clms Page number 59>

 rotational stop 85b. The fillet is due to the smaller surface thickness of the sliding range of the pivot edge (from 1 to 3 tenths of a mm less thickness) compared to the rest of the stress. This makes it possible to mount the pivot on the embrace in neutral position (the edge of the pivot being in contact with the fillet). The thickness of the sliding range 85a of the pivot edge increases slightly and regularly until the vertical cut. The rotation of the pivot edge on the sliding range, flexes the flexible part and reduces the volume of the neoligamentary channel at its height. When the edge of the pivot is in the vertical cut, the neo-ligament is extinguished.



   The upper proximal part of the constraint 109 comes into contact with the roof of the pivot chamber. It is flat, pierced centrally by the channel of the neoligament 105. We can see the leave, the vertical cut and the change in thickness the sliding range of the edge 85a of the pivot.



   The intermediate part 83 has the diameter of the wide internal part of the tibial implant and a thickness of 2 to 3 mm. The distal and proximal parts being of lesser thickness compared to the intermediate part, create two flats. The proximal flat 92b and the distal flat 92a. The proximal flat serves as support for the support flat 103 of the pivot, the distal flat or implant support flat of the embrace, rests on the support margin of the femoral implant 69 after insertion. This part 92a transmits to the tibial implant the forces exerted by the neo-ligament on the blocking system.



   The distal part is cylindrical and has two flats 84. It engages in the anti-rotational channel 70

  <Desc / Clms Page number 60>

 
 EMI60.1
 of the femoral implant, the volume of which it follows and emerges in the joint through its articular face 108. Its articular face is pierced by the foramen of the articular channel 107. The bulging part in the joint 106, prevents invasion by scar tissue in the anti-rotational channel.



  The pin G is shown according to the invention in Figures 18A, 18B, 18C, 1, 2 and 15.



  The pin is used to hold the pivot and the grip in the femoral implant while allowing the rotation of the pivot. When the pin is in the neutral position, the blocking system can be placed or removed from the femoral implant; when activated, the blocking system cannot come out of the implant. The pin is inserted around the perimeter of the pivot.



  The pin according to the invention is circular, with a thickness of 1 mm, it can be divided into two parts.



  The square section part 111 is located in the gutter 80 of the pivot and the enlarged part of the pin IIIb, 2 to 5 mm wide, has a notch 112.



  The insertion notch of the ellipsoidal screw is the place of insertion of the ellipsoidal screw. The enlarged part is placed in the expansion chamber 110 of the pin.



  The notch of the pin has two concavities 113, intended to receive the large convexities of the ellipsoidal screw 120a (pin in neutral position). A vertical groove 114 is dug in the center of each concavity from proximal to distal, in order to receive the small convexity of the ellipsoidal screw 120b (activated pin). In the neutral position, the pin does not exceed the diameter of the pivot cylinder, in the activated position, it exceeds it by approximately 0.5 mm, depending on the location where it is measured, in order to

  <Desc / Clms Page number 61>

 retain the blocking system in the femoral implant. The ellipsoidal screw is held in place in the notch of the ellipsoidal screw.



   The ellipsoidal screw according to the invention is shown in Figures 2.15, 19A, 19B and 19C. The numbers indicate the references of the corresponding figures.



   The ellipsoidal screw VE according to the invention is used to distend the pin and to engage a part of it of about 0.5 mm in the groove 72 of the femoral implant.



  It is held in place in the expansion chamber 110 of the pin, by the pin. The ellipsoidal screw can rotate 90 to 900 in both directions, with a noticeable projection. A color code will show the position of the screw.



   The ellipsoidal screw can be schematically divided into three distinct parts, the head of the screw 115, the ellipsoid 116 and the foot of the screw 117. These three parts are connected by small cylinders 118a and 118b.



   The ellipsoid 116 is located in the notch 112 of the pin, it has four convexities. The two large convexities 120a and the small convexities 120b. When the large convexities touch the large concavities of 1 pin, it is neutral and the blocking system can enter or leave the tibial implant. When the small convexities of the ellipsoid are in the vertical grooves, the pin G is activated and the locking system cannot come out of the implant. The head of the screw has on its upper face a hexagonal pitch 119 for the insertion of the screwdriver which allows it to be mobilized.



   After having deposited the femoral phantom, the surgeon will recover the guide wire by arthroscopy using an ad hoc clamp, through the femoral fixture. The other

  <Desc / Clms Page number 62>

 side, the guide wire is fixed to the free screw of the neo-ligament. By pulling on the guide, the damping cylinder is engaged in the bony channel, then screwed. At this time, the neoligament emerges from the femoral implant and the guide is removed. The locking system is engaged on the ligament, introduced into its implant, then the pin is distended. The surgeon can then place the pretensioner. The prosthesis can be configured.



   The cover cap according to the invention is shown in FIGS. 1, 2.20A, 20B, 20C and 21.



   The CC cover cap prevents invasion of the upper surface of the implant after the prosthesis is put into operation. It must also allow the infection of the extra-prosthetic part of the neoligament. Infection of the neeligament is necessary so that it is placed in the axis of the thigh and is less noticeable by the patient.



   The cap has the diameter of the implant. It has the appearance of a saucer, two faces of which are described, the upper face 129 and the lower face 130. It is pierced at its center 127, to allow the neo-ligament to escape from the implant and enter subcutaneous tissue.
 EMI62.1
 



  - t.



  The upper face is convex. It is hollowed out of a gutter 121 which leaves from the center towards the edge and is open from the top. The edge of the cap at the location of the neo-ligament forms a U 122. The upper face has a hole for the insertion of the fixing screw 125 of the cap.



   The underside of the cover cap is planar 130. It has two cylindrical nipples 124 2 mm high and of diameter distributed on either side of the hole

  <Desc / Clms Page number 63>

 exit of the neoligament. They serve to fill the clamping wells of the blocking system 97.



   The neoligament flexes in the s121 infection groove after it leaves the tibial implant.


    

Claims (65)

 EMI64.1   Claims: 1. Prosthetic system to replace the anterior cruciate ligament of the knee in two surgical phases, the first phase consisting in placing two non-removable osteointegrable anchoring bases and the superstructures of the first phase and the second phase consisting, when the bases of non-removable anchors are osseointegrated into the bone tissue of their insertion site to set up a functional neo-ligament system replacing the anterior cruciate ligament of the knee, and the suprastructures of the second phase, characterized in that the anchoring bases are formed by a tibial implant (IT) on the tibia and a femoral implant (IF) on the femur, the superstructures of the first surgical phase comprising on the tibial side an implant holder (PI), an external phantom (FE) and an internal phantom (FI),  and comprising on the femoral side a femoral phantom (FF), the superstructures of the second surgical phase comprising, on the tibial side, the removable ligament complex (CLA) and comprising on the femoral side a blocking system (SB), and the cover cap (CC). - zu 2. Prosthetic system according to claim 1 characterized in that the tibial implant (IT) is tubular, hollow and piriform and comprises three external osteointegrable parts constituted by the proximal part (1), the intermediate part (2) and the distal part (3), the external proximal part (1) having a thread (6) and a smooth border, the external intermediate part (2) being semi-cylindrical, making the junction between the external proximal part (1) and the external distal part (2) and having 4 side cubicles (4a, 4b, 4c, 4d) of  <Desc / Clms Page number 65>  tissue regeneration, the distal end (3) being tapered and tubular and having a bevel (7a), this tibial implant (IT) also having two ends or faces (FIT) and (FAT),  the FIT insertion face having a circumferential flat part 8, this tibial implant (IT) also comprising two internal parts, the proximal internal part (9) and the distal internal part (12a), the proximal internal part (9) having a part smooth (lofa) and a thread (lOb).  3. Prosthetic system according to claim 2 characterized in that the tibial implant (IT) has a length of 18 to 22 mm and a diameter of 8 to 12 mm.  4. Prosthetic system according to claim 2 characterized in that the external proximal part (1) has a width of 8 to 12 mm and a length of 9 to 11 mm, the external intermediate part (2) has a length of 2 to 4 mm and the external distal part (3) has a diameter of 3 to 6 mm and a length of 4 to 6 mm.  5. Prosthetic system according to claim 2 characterized in that the tibial implant (IT) is self-tapping.  6. Prosthetic system according to claim 2, characterized in that the distal end (3) is bevelled at 45.  7. Prosthetic system according to claim 2 characterized in that the internal proximal part (9) has a diameter of 4 to 7 mm and a length of 6 to 8 mm.  8. Prosthetic system according to claim 2 characterized in that at the distal end of the tibial implant (IT), the hollow part is cylindrical and forms a channel (12a) for passage of the neoligament.  <Desc / Clms Page number 66>    9. Prosthetic system according to claim 8 characterized in that an internal support flat (11) is located between the internal proximal part (9) and the channel (12a) for passage of the neoligament.  10. Prosthetic system according to claim 2 characterized in that the insertion face (FIT) of the tibial implant (IT) has a circumferential support flat (8).  11. Prosthetic system according to claim 1 characterized in that the external phantom (FE) is an element of hollow tubular and cylindrical shape, of the same diameter as the tibial implant, comprising a smooth external face, a proximal end or external emergence ( Emf) and a distal end or implant face (Fi), the external emergence face flush with the surface of the tibia and having an external bearing margin (16b), the implant face (Fi) comes into contact with the tibial implant (IT) by a tibial support margin (16a) and which rests on the support flat (8) of the tibial implant.  12. Prosthetic system according to claim 11 characterized in that the internal tubular part of the external phantom (FE) is wider in its proximal section (13), and narrower at the end (14), these two sections being separated by a circular support surface (15), the internal part (14) being threaded with a screw thread (17).  13. Prosthetic system according to claim 11 characterized in that the external phantom (FE) has a length of 20 to 27 mm and a thickness of 0.5 to 2.5 mm.  14. Prosthetic system according to claim 1 characterized in that the implant holder (PI) comprises an external fixing screw (VF) serving to fix the phantom  <Desc / Clms Page number 67>    EMI67.1  external (FE) on the tibial implant (IT) and a locking screw (VB) used to block the fixation screw (VF), these two screws (VB) and (VF) being nested one inside the other . 15. Prosthetic system according to claim 14 characterized in that the fixing screw (VF) has a head (TVF) and an extension (PVF) and it is axially hollow, the head (TVF) comprising a hexagonal nut (EVF), a circular collar (21) and a bearing margin (20) able to enter into coaptation on the internal circular flat (15) of the external phantom (FE), the fixing screw (VF) comprising an external screw pitch (19a ) of the same caliber as that (10b) of the tibial implant (IT), a cylindrical extension (19b) lying between this external screw pitch (19a) and the bearing margin (20), the fixing screw ( VF) being axially hollow over its entire length, with a cylindrical and smooth core at the level of its head, to be continued by a thread (23) allowing the fixing of the locking screw, and this thread (23) is extended by a channel (24). 16. Prosthetic system according to claim 14 characterized in that the locking screw (VB) serving to block the fixing screw (VF) in the tibial implant (IT) is axially hollow and comprises two distinct parts, the hexagonal head { 25) and its extension (29), the head (25) having a diameter less than that of (VB), at the level of its extension (29) having a thread (26) capable of being fixed in the thread internal (23) of the fixing screw (VF), a channel (28) passing right through the blocking screw (VB) which comprises at its tibial end a support area (27) circular. 17. Prosthetic system according to claim 1 characterized in that the tibial internal phantom (FI) to be placed in the external phantom (FE) comprises externally  <Desc / Clms Page number 68>  two parts, a plug (30) covered with a cover (33) and an elongated element, the shutter (31), the cover (33) being able to cover the external emergence (Emf) of the external phantom (FE) and the obturator (31) being able to extend into the implant holder and the channel (12a) of the tibial implant (IT) to emerge in the joint.  18. Prosthetic system according to claim 17 characterized in that the plug (30) is a cylinder of diameter identical to the internal diameter of the external phantom (FE), this cylinder being hollowed out by circular retention fins (34) of slightly larger diameter to the diameter of the cylinder, these fins used to maintain by friction this internal phantom (FI) in place in the external phantom (FE).  19. Prosthetic system according to claim 17 characterized in that the cover (33) extends beyond the diameter of the stopper (30) by a circular margin or covering edge (37) of the external margin (16b) of the external phantom (FE), this cover (33) forming a rounded arch (36) having in its center the emergence (35) of a thread (41) of a nut (40) which is crimped in the mass of the phantom.    20. Prosthetic system according to claim 17 characterized in that the part of the plug (30) opposite the cover is open and comprises a cylindrical cavity or chamber (38) of the internal phantom (FI) capable of fitting exactly on the head (25) of the locking screw (VB) and on the ceiling (39) of this chamber (8) is crimped the shutter (31) of the channels of the locking screw (VB), of the fixing screw ( VF) and the tibial implant.  21. Prosthetic system according to claim 1 characterized in that the removable ligament complex  <Desc / Clms Page number 69>  (CLA) includes a damping cylinder (CA), a cradle (52a), a neo-ligament (57), a slide (C), a free screw (58a), a spring (54), a seal ( 53) and a prestressing screw (VPC).  22. Prosthetic system according to claim 21 characterized in that the shock-absorbing cylinder (CA) has, externally, a smooth external surface (SE) (42a), and comprises at its distal end a device for fixing (43) to the implant tibial (IT), the neoligament (44) emerging from this fixation device (43) and the end or proximal face (42b) of the shock absorber cylinder flush with the surface of the tibial bone.  23. Prosthetic system according to claim 22 characterized in that the proximal face (42b) forms a vault (47) comprising four wells (48) arranged around a central hole (49).  24. Prosthetic system according to claim 22 characterized in that the fixing device (43) is a hollow cylinder over its entire length which continues proximally in the main cylinder (42), and it consists of two parts, a pitch of screws (45) and a filling stump (46), this screw pitch (45) being separated from the main cylinder by this filling stump (46), the screw pitch (45) being intended to be fixed in the implant tibial (IT).  25. Prosthetic system according to claim 24 characterized in that at the junction of the main cylinder (42) and the fixing device (43) is a flat (55) of the damping cylinder (CA) having the same width as the flat support (8) of the tibial implant.  26. Prosthetic system according to claim 21 characterized in that the internal part of the cylinder  <Desc / Clms Page number 70>  shock absorber (CA) is hollow and forms a chamber (CCA) closed at its two ends by a ceiling (51a) which is the internal part of the arch (47) and by the bottom (51b) of the internal part, the central hole the vault (47) being provided with a thread (49) intended to receive the prestressing screw (VPC) and the bottom (51b) having its central portion pierced and is extended by a channel comprising a proximal portion forming a cubicle (50b) of the seal (53) and a distal part (50a) allowing the passage of the neo-ligament (57) towards the channel (12a) of the tibial implant (IT).  27. Prosthetic system according to claim 21 characterized in that the cradle (52a) is disposed on the bottom (51b) of the internal part of the chamber (CCA) and is pierced with a channel having the diameter of the neoligament ( 57), this cradle (52a) being intended to receive the spring (54) in a gutter (52b) to immobilize it.  28. Prosthetic system according to claim 27 characterized in that this cradle (52a) is removable, and under this cradle (52a) is the seal (53a).  29. Prosthetic system according to claim 27 characterized in that this cradle (52a) has the diameter of the chamber (CCA).  30. Prosthetic system according to claim 21 characterized in that the neo-ligament (57) is a cord composed of a biocompatible, flexible, inextensible, dense material, of circular shape, crimped at its ends, the tibial end being fixed in the slide (56a) of the damping cylinder and the free end comprising a screw (FSC) set with a diameter slightly smaller than the rope with a thread.  <Desc / Clms Page number 71>    31. Prosthetic system according to claim 30 characterized in that the neo-ligament (57) comprises four sections: * the intra-tibial section (57a) which is internal to the removable ligament complex (CLA) and to the tibial implant (IT) ); * the intra-articular section (57b) which enters the joint by the tibial implant (IT) and leaves it by the femoral implant (IF); * the intra-implant section (57c) crossing the femoral implant (IF) from side to side; * the extra-prosthetic section (57d) emerging in the subcutaneous tissues.  32. Prosthetic system according to claim 21 characterized in that the slide (C) consists of a circular plate (56a) provided at its articular face with a central extension (56c) which crimps the tibial end (57a) of the neo-ligament (57), the articular face also being hollowed out by a circular gutter (56b) around the central extension (56c), this circular gutter retaining the proximal part of the spring (54), the proximal face (56d) of the slide (C) being flat and, at rest, abuts against the ceiling (51a) of the chamber (CCA).  33. Prosthetic system according to claim 32 characterized in that a space (59) is provided between the slide (C) and the interior of the wall of the chamber (CCA) to avoid a pumping phenomenon during the back and forth - comes from the slide (C) in the room (CCA).  34. Prosthetic system according to claim 21 characterized in that the free screw (58a) is crimped to the extraprosthetic femoral end (57d) of the neoligament (57) by means of a crimping (58b), and it has a not  <Desc / Clms Page number 72>  screw (58c) extended by a smooth segment (58d) which is used for fixing a guide wire used to facilitate the maneuvers of placement of the removable ligament complex (CLA).  35. Prosthetic system according to claim 21 characterized in that the spring (54) is embedded between the cradle (52a) and the slide (56a) of the damping cylinder (CA), the neoligament (57) passing inside of the spring (54).  36. Prosthetic system according to claim 35 characterized in that the spring is preloaded in the damping cylinder (CA) with a tension of approximately 20N.  37. Prosthetic system according to claim 21 characterized in that the circular seal (53) is disposed in the cubicle (50b) and encloses the neoligament (57).  38. Prosthetic system according to claim 21 characterized in that the prestressing screw (VPC) comprises a head (60a), a thread (60b) and an extension (60c), this prestressing screw (VPC) being screwed in the thread (49) of the roof (47) of the damping cylinder (CA).     39. Prosthetic system according to claim 38 characterized in that the prestressing screw pushes the slide (C) into the damping cylinder (CA) by a preset distance, thus preloading the spring (54) with a force proportional to the length of the extension (60c) of the screw (VPC).  40. Prosthetic system according to claim 1 characterized in that the femoral implant (IF) comprises a cylindrical part (61) over most of its length and a semi-cylindrical part (62) truncated at its  <Desc / Clms Page number 73>  osteointegratable articular end, and it also has a proximal end or face (FEE) and a distal end or face (FAF), and its internal part forms a channel (CIF) which passes right through it.  41. Prosthetic system according to claim 40 characterized in that the cylindrical part (61) of the femoral implant (61) has a thread (63) and has taps (64) towards its articular end and at the end opposite the femoral implant has a smooth border (65).  42. Prosthetic system according to claim 41 characterized in that the taps have lateral boxes (66) for tissue regeneration, these side boxes (66) being made in the mass of the lower part on a main flat (67a) of the main tap .  43. Prosthetic system according to claim 40 characterized in that the proximal external emergence face (FEE) has an edge (68a).  44. Prosthetic system according to claim 40 characterized in that the internal geometry of the femoral implant (IF) comprises two distinct parts, a proximal part 471) and a distal part (70) separated by a bearing margin (69), the proximal part (71) comprising a groove (72) the distal part (70) being narrower than the proximal part (71) and being truncated circular serving as an anti-rotational channel of the femoral implant.  45. Prosthetic system according to claim 1 characterized in that the femoral phantom (FF) has a cylindrical part (73) intended to fill the proximal part (71) of the femoral implant (IF), a cover (74) having a lateral overflow (76) used to cover the  <Desc / Clms Page number 74>  margin (68a) of the femoral implant (IF) and a obturator (75) at its distal end serving to fill the distal part (70) of the femoral implant (IF).  46. Prosthetic system according to claim 45 characterized in that the cover (74) has at its center a fitting and removal screw having a thread (77).  47. Prosthetic system according to claim 45 characterized in that the femoral phantom comprises retention fins (78) intended to hold it in the femoral implant (IF).  48. Prosthetic system according to claim 1 characterized in that the locking system (SB) comprises four elements: the pivot (P), the grip (E), the pin (G) and the ellipsoidal screw (VE).  49. Prosthetic system according to claim 48 characterized in that the pivot (P) is externally a cylinder (79) which has at its proximal end an insertion groove (80) of the pin (G), this cylinder also having a cut-out or insertion notch (99b) of the ellipsoidal screw (VE), this notch being made up of two notches, an upper notch (8la) and a lower notch (81b), this cut projecting over the proximal face forming l 'upper access (99a) of the ellipsoidal screw (VE), this cylinder (79) having at mid-height a hole (101) piercing it to its core (96a) this hole being intended to receive a stud, the cylinder comprising a proximal end or face (93) and a distal end or face (94).    <Desc / Clms Page number 75>    50. Prosthetic system according to claim 49 characterized in that the interior of the pivot (P) is divided into two distinct parts: * a narrow part (95) having the diameter of the neo-ligament (57) constituting the neo-ligament well of the pivot (P) * a wider part (96a) constituting the chamber of the pivot (P), the ceiling (96b) of the chamber of the pivot (P) being pierced by the neo-ligament well of the pivot (P) smooth, the chamber having a longitudinal arch or stop (102) of the pivot (P) used to block and unblock the embrace (E).  51. Prosthetic system according to claim 49 characterized in that the proximal face (93) comprises: * the central well (95) constituting the neoligamentary well of the pivot (P) piercing the pivot (P) axially as far as a chamber ( 96a) of the pivot (P); * two wells (97) located on either side of the central well (95); * a well (98) comprising a thread of screw to allow the insertion and the disinsertion of the blocking system and as well as the insertion of the screw which fixes the cap of  EMI75.1  cover (CC). - -. 52. System, prosthesis according to claim 49, characterized in that the distal face (94) is open and communicates with the chamber (96a) of the pivot by a large circular opening (104), the distal face (94) also comprising a support. circumferential (103) constituting the support flat of the pivot (P).  53. Prosthetic system according to claim 48 characterized in that the embrace (E) is integral with the pivot (P) and can rotate 900 on itself and consists of a tube of three successive thicknesses, hollowed out  <Desc / Clms Page number 76>  axially right through through a channel (105), the three thicknesses constituting three parts a proximal or constrained part (82), an intermediate part (83) and a distal part (84).  54. Prosthetic system according to claim 53 characterized in that the proximal or constrained part (82) is intended to enclose the neo-ligament (57) and to be inserted into the chamber (96a) of the pivot (P) and consists of two parts, a fixed part (PF) and a flexible part (PM), the fixed part (PF) continuing in the intermediate (83) and is integral therewith, the flexible part (PM) being dissociated from the intermediate part ( 83) by a horizontal cut (86) flush with it over 170 to 1800 and a vertical cut (87) over the entire length.  55. Prosthetic system according to claim 53 characterized in that externally at the proximal part, on the external part of the fixed part (PF) there is a groove (88) for the rotational guide of the embrace (E) on the pivot (P), the fixing stud fixed in the hole (101) of the pivot (P) emerging in this gutter (88) of the embrace (E), this joining device. the embrace (E) to the pivot (P) while allowing the rotation of the pivot (P).  56. Prosthetic system according to claim 53 characterized in that the intermediate part (83) has the diameter of the wide internal part of the femoral implant (IF), the proximal (82) and distal (84) parts being thick. less than the intermediate part (83) thus creating two flats, the proximal flat (92b) and the distal flat (92a), the proximal flat (92b) serving to support the support flat (103) of the pivot ( P) and the distal flat (92a) being intended to rest on the bearing margin (69) of the femoral implant after insertion, this part (92a) transmitting to the tibial implant the forces exerted by the neoligament ( 57) on the locking system (SB).  56. Prosthetic system according to claim 54 characterized in that the flexible part (PF) has on the 900 before the vertical cut (87) and horizontally, over its entire axial length a rectangular sliding range (85a) of the stop of the pivot (P) and 900 of the vertical cutout (87) there is a rotational stop leave (85b) due to the reduced thickness of the sliding stop surface of the pivot (P) compared to  <Desc / Clms Page number 77>  to the rest of the constraint (82), making it possible to mount the pivot (P) on the embrace (E) in neutral position, the stop of the pivot (P) coming into contact with the leave (85b), the thickness of the sliding range (85a) of the pivot stop (P) increasing slightly and regularly until the vertical cut (87).  57. Prosthetic system according to claim 53 characterized in that the distal cylindrical portion (84) has two flats and engages in the antirotation channel (70) of the femoral implant (IF) whose volume it marries and emerges in the articulation by its articular face (108) which is pierced by the foramen of the articular channel (103), the part (106) bulging in the joint preventing the invasion of the scar tissue of the anti-rotational channel.  58. Prosthetic system according to claim 48 characterized in that the pin (G) serving to maintain the pivot (P) and the grip (E) in the femoral implant (IF) while allowing the rotation of the pivot is an element circular divided into two parts, part (111) of  <Desc / Clms Page number 78>  square section located in the gutter (80) of the pivot (P) and an enlarged part (lllb) having a notch (112) for insertion of the ellipsoidal screw (VE), the enlarged part (lllb) being in a chamber expansion (110) of the pin (G).  59. Prosthetic system according to claim 58 characterized in that the notch (112) of the pin (G) has two concavities (113), a vertical groove (114) being dug in the center of each concavity.  60. Prosthetic system according to claim 48 characterized in that the ellipsoidal screw (VE) comprises three distinct parts: the head (115) of the screw, the ellipsoid (116) and the foot (117) of the screw, these three parts being connected by small cylindrical elements (118a) and (118b).  61. Prosthetic system according to claim 60 characterized in that the ellipsoid intended to be located in the notch (112) of the pin (G) has four  EMI78.1  convexities: two large convexities (120a) and two small "" convexities (120b).  62. Prosthetic system according to claim 60 characterized in that the head of the screw has on its upper face a hexagonal pitch (119).  63. Prosthetic system according to claim 1 characterized in that the cover cap (CC) a. the diameter of the femoral implant (IF), has the appearance of a saucer comprising a convex upper face (129) and a flat lower face (130) and is pierced in its center (127), the upper face (129 ) being hollowed out by a gutter (121) starting from the center towards the edge and being open from the top, the edge of the cap forming a "U" (122), the upper face having, in addition, an orifice  <Desc / Clms Page number 79>  (125) for the insertion of the fixing screw, the lower face (130) comprising two nipples (124) serving to fill the clamping wells 897) of the locking system (SB).  64. Semi-removable modular prosthesis of the anterior cruciate ligament of the knee which can be put in place thanks to the prosthetic system according to claims 1 to 63 characterized in that this prosthesis comprises a tibial implant (IT) a shock-absorbing cylinder (CA), a neo -ligament (57), a femoral implant (IF) and a cover cap (CC).  65. Semi-removable modular prosthesis according to claim 64 characterized in that the tibial implant (IT) the shock absorber cylinder (CA) the neoligament (57), the femoral implant (IF) and the cover cap (CC ) are as described in claims 1 to 63.