We are numerous to have taken part one day or the other in a think tank made up around a pathology or development of an implant. . and belong to group who contains seven members and who structured himself around the hip prosthese. They recall us the route of a group with success.

 

. : Dear Sirs, can you forward yourselves?

J. C. : I am an csotcina.comedic surgeon who works as a liberal in the region of Lion, in a structure , and which makes general csotcina.comedy with a very clear guideline on the hip prosthese.

: Me also, I am liberal csotcina.comedist, of Lyons formation. I made my assistantship and my in the service of the Instructor Georges de , and it is probably there that I had the vocation of the hip surgery. I left the in 1976 to settle in Annecy where the essence of my activity turns around the hip and of the knee, with an appreciably equal share of joint replacements and surgery of the sport.

 

 

. : You all are Lyons?

: Yes, we made all the seven our studies together. We followed ourselves since the test rigs of medical faculty, then during the day school and, then, the contest of boarding school. We have together all be assistants, us sharing between the schools of , and of . The other group members are Bruno , Louis , Jean-Marc , Claude , Alain . We exert all in Rhone-Alps area.

 

 

. : How were you brought to create group ?

: At the beginning, there existed between us a friendly link which had been tied during the boarding school and of the assistantship. But two or three years after our installation, we suffered all from our insulation what made us gather to share files, to travel, make bibliography.

: Yes, we found ourselves regularly at the time of the Lyons Days of the Hip that Georges de organized almost each year. In 1980, at the end of one day of conference, we met around a pot and we realized that we were each one only in our corner. We thus decided to make a “small club” which did not have any other claim but to join together a tape of buddies to share their professional difficulties. The meetings were in general held once a month and it was that practically all the questions were focused on the hip. With the whole beginning, it was the Society which lodged us in Lyon. It had already installed a structure being connected to a foundation, and placed at our disposal a room of work, with .

 

 

. : Congresses and conferences as occasions of meeting, were not enough for you…

: I believe that our meetings were complementary to conferences of the . The conferences, at Albert for example, it was nevertheless the “large mass”, therefore a vertical structure, and especially we needed a horizontal structure which enabled us to have freer exchanges and to travel. We wanted to discover the csotcina.comedic world which surrounded us and it is quite naturally that this Working Group became also a group of voyage.

 

 

. : There is always the possibility of travelling to in an individual capacity, why this idea of voyage of group?

: The individual voyage is very different; abroad and especially in the Anglo-Saxon countries, the voyage is probably more advantageous with fellow-members.

: Yes, one is received better in group made up: the expert who accommodates us feels a little more held to organize this meeting and finally it makes some much more than for only one individual. We thus always were very well accommodated and, moreover, the conclusions which we fire from the voyage were more enriching: we had not understood all the same thing, all not retained the same “idea forces”. Thus, with the return the synthesis profited from a synergy of the reflections; it is what makes the force of the group. This potentiation of the reflections appeared in a determining way when we combined our ideas for concrete achievements.

: Very quickly, we focused ourselves on the hip. Each one of us used implants different, but when we wondered whether we of it were content, there was always “yes, but…”. Each one among us had very personal ideas on the ideal prosthesis. The chance of the group, it is that there was a synthesis of the ideas with always somebody who made the criticism of the ideas of the other, but without nobody imposing his point of view. We thus created, not a “sheep with 5 legs”, but a prosthesis which gathered all the improvements or innovations proposed by each one and accepted by all.

 

 

. : Conversely, you could have fallen into the shelf from smallest common denominator. Many groups did not can innovate by excess “of balance”…

: And well in our case, alchemy was productive. Our operating process being revealed effective with the passing of years, we did not want to amend the receipt. Until lately, there was no question of amending the structure of the group, although one asked us to make enter of the “tenors”, of the academics, or the foreign personalities. We always resisted. In practice, the groups artificially consisted the manufacturers are unmanageable, nonproductive and often of simple commercial alibis.

: It there forever have of leader among us. All the proposals always be screened sterilizing of the analysis of the seven others and that forever be. On the contrary, that made it possible to make rather judicious choices: we never made large errors in our basic options.

 

 

. : You have 7 different there personalities and even if you appreciate yourselves mutually, it could have had large divergences?

: Yes, we are extremely different in our characters and our practice: we use initially different channels, and we have biomechanical designs moved away sometimes enough, but nevertheless we tested, in the Eighties to define a ideal hip prosthese for us. If we could as well advance during all these years, it is perhaps because we did not answer the commercial solicitations which did not correspond to our fundamental choices. Many groups which were federate only around one commercial idea did not last. In what relates to us, the idea founder, perhaps a little naive, was to work together, in all friendship and not to create a range of implants. Thereafter, coming success each one could be expressed and work with his of the group according to its personality and its competences: basic research, bibliography, clinical trials, statistics, communication… Everyone found its account there!

: Between our first meeting and our first project of implants, two years ago. The TITAN prosthesis was born in 1982.

 

 

. : Which was your philosophy of the hip prosthese at the time of the creation of your group?

: Georges de was closely related to Mac : the first prosthesis of Mac was posed in Lyon in 1969 and it was always faithful to this prosthesis even if then, it gave up the couple metal-metal. Georges de had made me go on a journey in England in 1972. I had remained a few times initially at John , then at Mac . I remember today still very precisely how much the cultural difference between these two characters had struck me. At , one was in a futuristic world, almost lunar; one worked out of diving-suit in rooms with laminar flow. The research laboratories were the gate beside the surgical units; the engineers were present daily in room and the “TEAM” was already very international. The universe of Mac was quite different. The operating-room gave on the surrounding countryside and meadows; one or two operations was enough in the course of the day and, after a cup of tea and some cookies, it was high time to leave to make a golf! I had quickly understood why my owner felt so near to Mac . It is there too that I was marked by the antéro-external channel of access of the hip that Mac realized marvelously. I always continue to use this channel, on csotcina.comedic table, like two other members of a group besides. But for the remainder, I further acknowledge not to have pushed fidelity and, already at the time of my installation, I had given up the prosthesis of Mac for that of , like almost all the other group members. Here where was our philosophy at the time.

: Yes, the main part of the prostheses posed with beginning of the year 80 was cemented prostheses monoblocs. “Without cement” was still with its stammerings and gave of it more vexations than of satisfactions. In deprived, we were held to pose prostheses which had proven reliable. We used almost all the prosthesis and it is starting from the implant of Maurice that we tried to imagine an improvement of his stability. The basic idea was to make evolve/move the “blade of saber” of the to obtain a stability in all the plans of space thanks to the metaphyseal “gyro caging”. From this widening out was born the concept of stereophony-stability, asset determining for TITAN.

 

 

. : It was your first baby?

: Yes.

 

 

. : Which were the characteristics of TITAN?

: The first was the form with its “gyro caging” metaphyseal original. The second was the material: titanium alloy forged on anodic-smooth surface. The third was its modularity with truncated commitment of the prosthetic head making it possible to vary diameter (22, 28,32), length and especially to introduce ceramics alumina.

 

 

. : Had you also integrated the problems of spacer?

: Not, not at the beginning. But we were very sensitive to expensive Maurice planning and the . The problems of “offset” were not topicality, but we were quickly sensitive to the problems of , in particular some and TITAN existed very quickly in two series: one normal and the other lateralized one.

 

 

. : Who manufactured it to you?

: Many large firms had been declared interested by our prosthesis but, to minimize the investment, they wanted to amend it according to their constraints of manufacturing. Later on, we came into contact with the firm. This society manufactured surgical instruments and had a distribution network. Wishing to manufacture its own implants , she sought a group of design. The group and the firm launched out together in the adventure of TITAN.

 

 

. : Which were the performances of TITAN with use?

: With use, we were completely satisfied if not the project would not have continued.

: I always pose it and there no was change on the TITAN prosthesis because we had the chance not to make an error on the form, nor on the surface quality: we had from the start a forged titanium, polished, which did not give us any the problems of corrosion and osteolysis that other surface qualities could generate. As always, in a concept one never should separate the form, material and machining.

 

 

. : How was it received by the colleagues?

: At the beginning, the prosthesis was not to have the dissemination which she knew. It was a prosthesis intended for group . It had given place besides to no patent and thus we were not financially implied. The group posed between 700 and 800 prostheses a year. Then, thereafter, Patrick asked us to authorize it to propose TITAN with other csotcina.comedists. Having tested over one long period, we gave our agreement. The TITAN prosthesis then began a French and international dissemination. Its performances were not contradicted with the passing of years and we had recently satisfaction to find it in the first places of the “signal ” of the Norwegian register of the hip prosthese, in front of ! … but with equality with the Coral.

 

 

. : Why did you evolve to without cement?

: It is neither by dissatisfaction, nor for mercantile reasons. Indeed, the day when we proposed a new concept of prosthesis without cement to our manufacturer, we gave him many concern! In 6965 81, one spoke much about the “disease of cement”. It was thought that all the failures of the cemented prostheses were due to cement: that it aged badly, that it was fractured, that it gave granulomas, that it was responsible for the corrosion of metal… Thus by a a little simplistic reasoning, it was trying to abolish cement to solve all these annoying problems.

 

 

. : How did you proceed?

: The mode of the time, it was porous metal. We thus left to the United States at the beginning of 85 to make a round and to on the spot see what that gave. We returned fairly enthusiastic. On the aircraft of the return, while reading a review of fundamental science, we fell on an short article on the hydroxyapatite. We told ourselves that if one could implement this material to a prosthesis, one would have perhaps found a solution with “biological” fixing. We referred to this runway of search a few times after our return of the United States at a meeting of the group where Patrick was present.

: He had already proposed us a curious material which was called the “”, of which he had acquired the European dissemination. The original mode of fixing of this “” was to support fibrous which was to have a function of shock absorber of the prosthesis.

The group, balancing possible individual racings, by a veto impossible to circumvent disallowed this “innovating” proposal. But to return from there to our option of of the stem by calcium hydroxyapatite, nobody differently controlled the depositions than by hydrolysis, method too much fragile for an csotcina.comedic use; it was a little the impasse.

 

 

. : And then?

: Patrick finally learned that there was an university laboratory in Germany which worked on the deposition of hydroxyapatite by plasma gun. He negotiated tests of coating with TITAN implants and especially to allow the adherence of the hydroxyapatite.

: Without we knowing it, two other teams worked on the hydroxyapatite at that time; initially in England which, In addition, made cover its first stems in the same German university laboratory and in Holland the chance thus made that, without knowing, three teams started into 85 and one makes cover in an almost artisanal way their first prostheses with ceramics of hydroxyapatite.

 

 

. : How do you carry out the clinical trials?

: We carried out a short series of covered implants of hydroxyapatite and posed we them. It was thus about basic the TITAN prosthesis, but whose surface quality had been amended; we called it the “”. That can make smile but it was the reality of the time; no Commissions of homologation, not marking EC. Actually, we did not take many risks. The hydroxyapatite was known and used in surgery, in particular maxillofacial since 1976 by . It was about a material of filling and one knew that he was neither toxic, nor inflammatory and that there was no specific carcinogenic risk. The innovation and the unknown came from its use in thin layer. Our animal experimentation had shown that the coating of dual-sided out of titanium by a layer of hydroxyapatite made it possible to avoid the fibrous after implantation in the wing of the dog. The implant was not recognized any more like a “foreign body”. We thus establish these “” and we were from the start filled with enthusiasm by the total clinical silence to which our preceding experiments of without cement had not accustomed us: no pain of thigh, even with a total immediate support. They behaved exactly like cemented prostheses.

: The initial series understood 70 implants, that made 10 prostheses each one. It is a tough practice to do everything to 7. All the meetings one disembarks to 7, one discusses to 7, one works much but always to 7.

 

 

. : You have famous precedents: 7 dwarves of #FFFFFF Snow…

: Of agreement, but we have neither Grumpy, neither Teacher, nor apparently Simplet! Therefore, we made our initial series and observed an absolute clinical silence and especially of the radiological images which one had never seen. This ossification which comes to occupy space between the cortical one and the prosthesis. At the end of a one year observation, we validated the hydroxyapatite. This new biomaterial seemed quite higher to us than all the balls and all surface qualities which we know.

 

 

. : Did you plan to amend the form of your implant for without-cement?

: Yes, of course, it appeared obvious to us that biological fixing could only go hand in hand with a good mechanical stability. We were very satisfied with the primary stability of TITAN but it seemed essential to us for without-cement to create macrostructures of surface. After a multitude of meetings during which each one brought its prototypes, its drawings, its moulds on plaster, modeling clay and other wood carved, we chose the final structure made of horizontal scratches in the metaphyseal high party to be opposed to the depression and of diaphyseal vertical scratches to be opposed to rotation with an area of a little sophisticated transition. This drawing was adopted by the 7. Our only divergence related to the flange because we did not have more arguments to put of it, that not to put some. By honesty, we made manufacture the two versions so that holding them of each option make their experiment and that the future can decide between them. It should be recognized that today still the debate is always open; statistically, we were not the proof of the very clear superiority of an option on the other, even if each one is closely persuaded that its option is better than that of the buddy!

 

 

. : Who had the idea of the scratches in the two directions?

: It is Jean-Claude.

: The problem is not as well to have the idea as to make it accept by the others! Nobody knew what became the hydroxyapatite at 10 years and if this were only one transitory ceramics; it was necessary that the osteogenesis of cicatrization meets a certain number of on which the newly formed bone can be fixed. And like, we were always obsessed by these questions, at the same time of depression, and especially of rotation stability, we combined this slotting with this original form. After 50 drawings which all were refused, it is finally the last which was validated by the whole of the group. One did not have that they are microgrooves, he was not necessary that they are teeth of saw. In addition, it was necessary that the general “design” is pleasant to look at and, finally, that manufacture is compatible with the work of a good inventor. Most astonishing it is that our histologist, Patrick , discovered fantastic virtues with these scratches and it shows histologically that it is at certain places of the scratches, in particular at the summit of the peaks, on the side faces, that one observes the maximum of osteogenesis.

 

 

. : When was it marketed?

: In 86. The first implantation took place in September 86. We called it Corail because it is a name which makes dream and then because the #A6FFF9 and the synthetic hydroxyapatite are compounds to which the chemical and crystallographic structure is very close to that of the mineral phase of the bone. They all are of apatites. It is thus not natural #A6FFF9 but this coating of hydroxyapatite resembles the #A6FFF9 structure. This time we had deposited a patent!

 

 

. : How was held the follow-up?

: We started with prudence. The first year, the number of the installations was modest. We selected the patients according to the age, of the quality of the bone, the form of the femur. Thereafter, these criteria were abandoned. We developed a real range of stems. It was also necessary to draw a metal-back with a coating of hydroxyapatite and we created, for reasons of individual option, two types of near-made: near-made screwed and near-made it impacted. We were for a long time fervent supporters of screwed but it was not the mode and the screwed had many detractors who were based on the catastrophic clinic experiment of the screwed rings not .

In same time, we worked on the specific implants adapted to the Overhaul, problem which was more and more frequently encountered. The aim was thus to create a true “Corail system”, complete, coherent, concerned with the same concept.

 

 

. : Which kind of head you had chosen?

: The TITAN prostheses had heads of 32; for the Coral, we simultaneously had the heads of 32 and m, with a marked preference for the alumina ceramics.

 

 

. : How behaved screwed ?

: This mode of fixing, associated with the coating of hydroxyapatite to us forever given concern. We thus continue to strongly promote the same screwed which will be soon available besides with a ceramic insert.

: There was a large evil understood around the screwed cups. One put in the same bag all kinds of materials, forms and surfaces. It is certain that the surface treatment is fundamental. With regard to our covered with hydroxyapatite, we did not observe basic differences between the two models; that the setting in stress of the bone is made by screwing or that it is done by impaction, it is exactly the same thing. In the long run, they behave appreciably in the same way, with nevertheless, a light advantage with the screwed cups car-tarodeuses. I believe that the whorls, the macrostructures, are there for something. In the Norwegian register, it is the cup which with the best reliability curve of all the analyzed implants .

 

 

. : How do you select the without-cement indications?

: We do not use practically any more cemented prostheses and this, whatever the patient, because the process of osseointegration occurs in a way identical to any age, independently of the quality of the bone. It is an almost reproducible constant phenomenon. One of course can, to discuss the economic problem, but in biological term, a prosthesis hydroxyapatite is integrated in the same way at a young patient and an old patient, on an osteoporotic bone or a dense bone.

 

 

. : You did not note a clinical difference?

: At all; this is why, we do not have selection criteria as could define some.

 

 

. : With what does resemble a Corail prosthesis established thirteen years ago?

: The development of the radiological images translating the osseointegration is spread out over 12 or the first nths. Beyond, the images are perfectly stable. You can superimpose radiographies at 5 years, at 10 years and at 13 years now, there is no amendment of space between the prosthesis and the . There is no edging, not reactive line, not of osteolysis. Of course, there are some amendments of the site of implantation. The “stress ” is in particular responsible for the replanning of the . The edges swell, but there is not a radiologically visible cortical atrophy. That leads me to speak about a fundamental characteristic of the #A6FFF9 which is its total coating ha. One was criticized much on this subject and one had predicted to us the blocking of the prosthesis in his distal part, big problems of stress-shielding and of course of the major femoral damage if, by misfortune a firmly fixed implant were to be withdrawn. These pessimistic predictions rose from the analysis of the madreporic, massive and rigid prostheses which gave, indeed, of the important stresses-shielding and posed enormous problems of extraction. Actually, it is now quite allowed that it is not the coating as such which created the stress-shielding, but the rigidification of the femur prosthesis. From where interest of a titanium stem, conical form, not having a very intimate cortical contact. We are thus very far from the concept of “made yarn”. The vast majority of the #A6FFF9 does not involve any visible amendment on the cortical ones, but process of the osseous, infra-radiological rarefaction exists, like one indeed shown our studies. The loss of density is from approximately 30 to 40% in area , and it is known that one needs a loss from approximately 50% of the bone mineral contents so that a radiological translation is had. We used since 1989, the techniques of and I believe that we are a little the pioneers in the implementation of this method to the analysis of the perish-prosthetic rehandlings.

 

 

. : And if one compares with the cemented prostheses?

: The cemented stems are often smaller diameter to leave the place to the cement mantle. The unit is thus less rigid, therefore there exists less stress-shielding.

 

 

. : How TITAN cemented of are 20 years ago?

: We are not yet 20 years old of retreat. We continue to follow these prostheses and, in term of sealing, the quality of the long-term outcome is completely satisfactory, with a curve giving a probability of survival from 96% to 10 years. I already referred to the site of observation privileged and demanding which is Norway.

TITAN evolve/move at the rate/rhythm of wear of polyethylene and thus with granulomas. With the passing, one reports that our best TITAN are the very first ones, those established with a total cup EP and not with metal-back cemented.

 

 

. You have the impression that the couple of friction alumina/polyethylene is tolerated much better than the couple steel/polyethylene?

: The answer is not simple because one puts questions about the quality of polyethylene, in particular that which was provided to us with beginning of the year 90. The couple ceramics-polyethylene of the Nineties indeed, forwarded unexplained wears whereas older polyethylenes did not give any, even with heads of metal m! Indeed, we took again a certain number of cups near-made with polyethylene core very worn, important granulomas on the level of the mining area and a beginning of granuloma with the level of the great trochanter or . These prostheses were revised on the slope and the femoral granulomas , but one removed the stem forever. No Corail stem was thus withdrawn, from where the idea, rather widespread in the users of hydroxyapatite, that this coating is an obstacle with the circulation of the fluids and thus a barrier with the migration of the remains. But, one should not dream, the remains will migrate perhaps more slowly but will migrate all the same. From where need for improving the couples of friction and our development towards ceramics-ceramics.

: In 90, we established a hundred couples alumina-alumina on cup hemispherical with coating of hydroxyapatite, then we stopped to study their to still become with prudence. We started again, in years 97-98, of new implants with couple of friction interchangeable alumina. We think that it is surer to have a couple alumina-alumina to avoid than the hydroxyapatite is shown to create of a wear with third body.

 

 

. : Is the current Corail stem the same one as 13 years ago?

: Exactly and the characteristics of the coating are the same ones. The is carried out by in Toulouse: use of atmospheric plasma gun, icrons thickness, total coating. We met a few times ago in Malta with the whole of the layers of the Coral, by asking whether it were necessary to change one of the parameters of the stem, to make an unspecified improvement.

A very broad consensus emerged to keep the #A6FFF9 such as it is, without changing the form and the coating, in its nature or its extent: no scientific argument to introduce triphosphates, or double-layered…

 

 

. : #A6FFF9 with the air to have succeeded in …

: Indeed, the #A6FFF9 succeeded very well in Patrick ! It even had problems to manage its international expansion… There is not much country of Europe where it is not established. Most difficult was to convince the FDA in the United States: after two years of combat the Corail prosthesis received its approval and it was a very great satisfaction for us and a great victory for . But, as from the moment when this system took such a rise, the regional and national structures of did not follow and, to our regret, our manufacturing French passed the hand to an international society, which, itself was bought up by Johnson and Johnson.

 

 

. : Does that change the things for you?

: We started from a small structure with a research team and development based to Chaumont which was entirely devoted for us, extremely reactive and careful with all our suggestions. We find ourselves now within a heavier structure, but more sophisticated also, which does not launch out in any “csotcina.comedic adventure” and which wants that all is well controlled and is integrated in the international policy of the group. Thus we actually lost in flexibility, of speed of realization, but we gained into serious and quality of the tests, like in rigor of manufacture. The logistic power of our new industrial partner is also a major asset which makes us pass from a hexagonal level, with an international level. We went to communicate, operate and make in the whole world. This surgical adventure doubled discovery of what were the marketing and the launching of a product. Without forgetting the fact that, since we want to defend our ideas, it is necessary that we manage to make pass our “papers” in the official congresses. It is for us an exceptional adventure in term of opening.

 

 

. : Do you think that such a route for an work group is possible today?

: Such as we lived it, surely more. We profited one very favorable period. The stresses such as law , homologation, marking EC, were non-existent and the general economic context was carrying. Today, each one of our suggestions raises financial and strategic objections related to the change of economic situation, before being forwarded to the office of research and development. We want of course to continue to make evolve/move the products but it is much more difficult. We live one period of regrouping which can make fear that in the medium term there is nothing any more but one half dozen csotcina.comedic manufacturers of implants in the world. The era of the “designers surgeons” such as we knew it is finished and, In addition, when one speaks about it with our American business partners, they do not understand that group can function thus; they do not understand that it is the group which forwards ideas to a research department. In the United States it is the reverse, it is the research department which conceives, develops a new implant, then search of the surgeons who agree to defend the new concept after having tested it.

 

 

. : One asks for how engineers could all alone integrate the multiple parameters which govern the surgical installation of an implant?

. C: It is true, but the current position is also the consequence of considerable excesses. In years 70-80, there was “are delirious” in the design of the prostheses. Any surgeon was designer, any group his prosthesis: the market proposed all and its opposite! Obviously, this flowering translated also a certain inventiveness because the motivations were not only commercial. There were true good progresses, even if that were a little disordered. One can return the ball besides to the large teams of American designers who sometimes tried to impose to us “on the gun” products which collapsed two or three years afterwards, whereas they had all the scientific assets, data-processing calculations and design by finite elements…

Admittedly, times changed but I believe in the primacy of the man of ground and the surgeon compared to the engineer, at least in the range of the implants which we know. With regard to new materials, it is possible that the engineer overrides the surgeon, but it should be stressed that we always worked in a very narrow way with the fundamentalist ones, in particular in with Patrick .

 

 

. : You are always convinced of the future of the hydroxyapatite?

: More than ever. It is true that there was at the beginning a shooting of important barrage against what its detractors called the “magic powder”, but all those which criticized us are hastened to study it well. Certain surgical teams, of the great services however very , recognize his interest. The last symposium of in the femoral recoveries confirmed its performances.

Currently, there is no more one firm which did not make search in this management and which does not have a range of implants with hydroxyapatite. One is well persuaded that it is not the only management, but it is certainly the most original discovery of these 15 last years in . It should however be repeated that the coating of an implant is a thing, but which it should never be dissociated of the form and material.

In , the success depends on a channel of qualities whose relevance of the analysis and quality of the surgical act are not the least links.