The 20th congress of the was held last October in Paris with in the chair Yves . We met there David of Chicago which played a leading role in the development of this scientific society and which was one of the first North-Americans to be implied in the surgery computer-assisted.

MO: Of what does consist the congress of the ?

:  means International in . Its organization started in 1988 and at that time, it named International . In the middle of the years 1980, there was an interest growing for the installation of cementless implants in particular on the level of the hip. There were many debates on the requirements with the perfect femoral stem and hip prosthese installation of in particular without cement. One of the subjects was of knowing how to obtain a solid primary femoral fixing without compromising the osseous inventories in the long run. It was known that the long stems femoral covered with a porous surface could give a rigid fixing. However, one feared in these cases the “stress ” which on the level of the proximal femur would cause a bone resorption. It was feared that this stress does not weaken and even the proximal femur does not make disappear and in the long term does not compromise distal fixing. One had a presentiment of that if the implant could be fixed firmly at the level , there would be no diversion of stresses. The anatomy of the proximal femur, contrary to the diaphysis, being extremely variable from one individual to another, one was worried by the manner of obtaining a good fixing on the cortex . It is at the same time that the techniques of osseous scanning developed. A certain number of American csotcina.comedic surgeons, engineers and manufacturers thought that to scan it could help us like database, in order to carry out femoral implants to measure which could be fixed precisely in the proximal femur. It was thought at the time this precise filling would ensure an effective stability of the implant. Thus, the femoral bone could come to be fixed at the level of the implant and to reorganize the aforementioned around. We were convinced that this concept had enormous potentialities but which it required an implication of experts of the whole world. This is why we decided to create the i.e. the International Society of the Prostheses to Measure.

MO: When did take place the first meeting?

: In 1988 in Dusseldorf. In fact it was one of the first if it is not the first of the congresses on what one calls today the CADS i.e. the Computer . It was obvious that to succeed in the technology of the implants to measure, he was necessary to imply as much the csotcina.comedic surgeons, the engineers that the manufacturers. This is why international representatives of these three trades took share at the initial Steering Committee and it had been decided that to encourage an international participation the congress would be held in alternation in Europe and in the United States. At the time, there were no Asian participants but progressively of the growth of society a certain number of people of the Asian countries were interested in our work and this is why thereafter the program of alternations of congress implied Asia. The congress of Dusseldorf was especially devoted to the organization of the , whose first official meeting took place in Chicago. It was in 1989 and I chaired. The 3rd meeting was taken place in Nice and Jean Manuel chaired. In the first years, the had primarily concentrated on technologies which made it possible to develop total prostheses to measure. Many of these technologies allowed prosthetic progress as regards joint replacements apart from the fields of the to measure. Progress in robotics, in surgery computer-assisted, couple of friction, drawing and manufacture of the implants is repercussions of the work initiated by search on the implants to measure. With the multiplication of the centers which all over the world used implants to measure, knowledge on the conditions of success of a prosthesis without cement increased and led to the focusing of models of series having a better fixing. This is why, in the middle of the years 1990, it became clearly that an expensive manufacture to measure was not necessary for the great majority of the total prostheses of hips and knees. The founders of the thus decided to re-examine the role of their organization. There was a strong will to continue collaboration between csotcina.comedists, engineers and manufacturers, in the field of new technologies of the prosthetic surgery. There was also a wish to continue the development of all these technologies which had been initiated by the . This is why the founders of the as well as very many surgeons and manufacturers decided in the middle of the years 1990, to extend the field of this society to all technologies concerning the prosthetic arthroplasty and it why new name of society: the . Peter of Dusseldorf was the organizer of the first congress in 1988. There were approximately 80 participants.

MO: Did you have poor performances with the implants to measure?

: Not. In fact, the results of the implants to measure are good. For example, in 2000, I started to pose a series femoral stems to measure without cement. I continued this series until 2004 and I had not had any failure of fixing. In addition this initial experiment led me to design a stem to measure with metaphyseal fixing, which I use since 2005. The drawing of this implant was the fruit of the lesson of the first stem to measure. There had been no failure of fixing of this implant to date. However, these last years, of many femoral stems without cement current were developed and posed with identical results in clinical and radiological term. These implants are obviously much less expensive than those done to measure. In addition they are immediately available and do not require an intricate operational planning, including scanners. This is why today, the use of the implants to measure is limited to very specific indications, in particular the very specific anatomies, the massive tumors or rebuildings.

MO: How were you implied in this field?

: I started to work on the implants to measure with a small company of California, , which towards the end of the year 1980, developed an expertise in this field. I had been introduced to this society by Doctor , one of the developer of . The company understood a group of engineers who were really very interested by a close cooperation with the surgeons, in order to develop the technology of “to measure”. As for the whole of the techniques based on data processing, it is very important that the clinical requirements such as for example the size and the form of an implant is clearly forwarded of the surgeon to the technician. Engineers de spent the hours to the with me, to understand how to obtain the best implants to measure. Thus we defined the rules of manufacture of the femoral stems to measure.

MO: Which was your professional statute?

: When I began this work, I was the founder and the Director of the Gasket Rebuilding Implant Service in Memorial of Chicago and instructor of “” in off Medicine. Besides I have always these functions. Initially, I made primarily rebuilding of all the hinges i.e. hips, knees, ankles, shoulders and elbows but for 10 years, I have limited myself to the hips and the knees.

MO: What led you to use implants to measure?

: In 1988, when the use of the uncemented implants to measure started in the United States, there were many questions without answers about the interest of the cementless implants. This is why, their use was limited to the young patients, i.e. less than 65 years, which most probably would require for a resumption of their hip prosthese if it were posed with cement. We did not have many data allowing to affirm that a cemented stem was likely to last at least 15 years. This is why the patients with an life expectancy of more than 15 years were regarded as reasonable candidates for prostheses without cement. In 1988, I made the decision to use cementless implants to measure, for this patient group. And of 1988 to 2004, all the uncemented femoral implants of first intention which I posed were made to measure. In the first 5 years this experiment, I developed the specification of a stem without painless and durable stable cement. That related to the form, the size and the aptitude for the filling of the proximal femur. A scanner of hip and also of knee to calculate the , was produced and sent to the manufacturer. The aforementioned made a data-processing model starting from the data of the scanner and the diagrams were addressed to me for evaluation and agreement. Lastly, the implant and of the adapted graters were manufactured. The whole of the process, since scanning it until obtaining the implant, took about a month.

MO: Were you never confronted with unsuited implants?

:  That was one of our great concerns at the beginning of the project. This is why, at the beginning, I always had a plan B which enabled me to carry out the intervention even in the event of bad design of the implant. In fact, of the beginning, I thought that the manufacturers would not manage to make an implant adapted to each situation whereas it appeared that the true problem was that I needed a technique which guarantees the correct installation of the implant. The elements of the which I had determined implied that the stem could be established only in only one manner. A specific access and specific graters were to be carried out so that the implant is placed with precision. In fact, with one or two exceptions, we never had problem for set up an implant to measure in a femur. As that arrives sometimes in current stems without cement, we had some cases of fracture not moved during the femoral preparation. Those required simple hoopings but at all did not amend the rigidity and the perenniality of fixing. These fractures became exceptional after the first year of our experiment.

MO: And with the knee?

: Even if we had many discussions on the possible interest of a “”, I thought, as it was not possible at the time to rebuild to measure the joint surface of the knee, than the interest of the implants to measure for the knee would be very limited. But I believed much in the “” in the resumptions of knee prosthesis in order to mitigate the osseous met in these situations. However, we decided to rather direct us towards the focusing of a prosthesis of recovery which became the first largely modular prosthesis of recovery in order to adapt as well as possible to the tissue losses. A good part of the concepts of this modular prosthesis came from the data scanners obtained when we plan to make a to measure.

MO: Did you preserve the posterior cruciate in your current ?

: Yes, I had had my formation at the university of Harvard. Contrary to the training programs influenced by in Special of New York, training in prosthetic surgery of the knee in Harvard, directed by Clement , insisted on the importance of the conservation of the posterior crusader for any total prosthesis of knee of first intention. At that time, much of patients candidates to knee prostheses in Harvard, had rheumatoid arthritides and we used prostheses preserving the posterior crusader for these patients and even if those had an important deformation. When I began my practice in Chicago, I used prostheses with and without conservation of the . However, in the last years, I leant towards the implants whose drawing makes it possible to do without the . Although the postéro-stabilized prostheses are largely used in the whole world, I think that in the next years, we will witness a development of joint surfaces which will abolish the need for a polyethylene pivot in the total prostheses of knee of first intention. I believe that these implants will give less wear of polyethylene and less pains former compared to the postéro-stabilized of today.

MO: When did you put yourselves at the surgery computer-assisted?

: I started to work on the surgery computer-assisted in 1990.
We developed in , a system of robotics to establish the total prostheses of knee. We led this search in partnership with the program which had, to the beginning, summer developed by Service in California. However, as one advanced, I had the impression that the use of robotics for set up these implants was too expensive, cumbersome, and intricate for a standard practice. This is why I turned towards the the surgery computer-assisted. Precisely to this period, I had been invited by Philippe of the University of Grenoble to join Michael and to evaluate the work which had been made in Europe on the navigation musculo-skeletal and financed by the European Union. The evaluation of this work enabled me to see the first navigate knees, without image, carried out by and Picard in Grenoble in 1997 with like navigation system. Allured by this experiment, I succeeded in obtaining a prototype at the University of . Doctor Fred Picard who had just finished his boarding school at that time, came to Chicago to help us to install and start the system. was developed in Grenoble with supports French company. This society marketed the total prosthesis of knee which was used at that time with . was then owner of and the of in the United States was ensured by an appointed company . By chance, the former chief executive of , company with which I had worked on the implants to measure, was in 1998 the chairman de . Thus it was possible for me to introduce surgical navigation in before these aircraft are certified by the FDA. One of the consequences of this investigation was acceptance by the FDA of like first navigation system without image in the USA. This initial work with license a continuous development of the programs of which now contain an implementation for the resumptions of knee. It also provided information which made it possible to guide the clarification of knee prosthesis. Now, the knee understands at the same time prostheses of first intention and recovery, and this with a system of manual or navigate instrumentation.

MO: Which is the specificity of your knee?

: The system of knee prosthesis was conceived for an optimal fixing among all patients, a minimal polyethylene wear, a maximum sector of mobility, a complete range of implants for prostheses of first intention and recovery and to allow a precise implantation with a navigate or conventional instrumentation. It is strong of an experiment of more than 1000 prostheses navigate, and collected informations during these interventions which we drew this implant. There are 10 femoral sizes, 9 tibial sizes, which enable us to have a couple of implant almost to measure for each patient. We particularly took care to minimize the thickness of polyethylene. Independent studies indeed showed that the models with conservation of the crusader, with sacrifice of cross and have more the current low level of wear.  In the years to come, the femoral components with negotiable instrument of surface still will decrease wear and will abolish concern in connection with the reactions to the metal particles. to allow us to decrease the complications relateds to the application of metal at the femoral level. The fémoro-patellar hinge was drawn in order to obtain the maximum of bending. of first intention and overhaul was drawn to be used in an effective, very precise and less invasive way, with the navigation system. The underlying principles with navigation were at the basis of the adjustment of the minicomputer-invasive manual instrumentation used for . From 2000 to 2005, I navigate all my total prostheses of knee to understand exactly the principle of navigation without image. It is this experiment which enabled me to develop a manual instrumentation, making it possible to do without navigation.

MO: How long navigation consumes?

: At the beginning, navigation without image lengthened about inutes a total prosthesis of knee. Now, the program of navigation was divided into two. The surgeon can choose which party of the intervention it wants to navigate. For example, certain surgeons want to use navigation only for the balance in bending and extension. Other surgeons can want to use navigation to guide the femoral or tibial cuts. Thus, navigation will add to the maximum inutes with the procedure or although inutes according to the needs: inutes, it is the time which it takes for set up the sensors and to carry out the booking of the data. It is important to understand that the realization of the without navigation becomes more precise and powerful when the surgeon learned has to navigate. Currently, we use navigation in order to learn with our interns the principles and average the techniques to correctly pose a total prosthesis of knee.

MO: Do you make osteotomies?

: Seldom although I think that there are deformations which are excellent indication with the osteotomy. But I seldom meet such situations. Moreover, in the measurement or the become increasingly sure, the level of the activities of the patients carrier of increases. Many patients among whom one carried out osteotomies to allow them the sports practice, can now do it with a .

MO: Do you make the “Plain one”?

: Yes. For correctly selected patients it is the ideal prosthesis. However I have very strict indications on the matter. Kind I have only 10% of my patients who lend themselves to it. In addition, the performances of the do not cease improving and thus the differences in results between these two implants are reduced. Nevertheless I think that there will remain always a reserved domain with Plain and that its field of indication will increase when the implants with biological fixing are available.

MO: What do you think of PUT at the knee?

: I think that the principle of the respect of tissues in the is good. However this concept is not inevitably adhered to at the time of the installation of a by an small incision. The concept of respect tissue was in the beginning many progress as regards . The instrumentation is smaller and intrusive and the ball joint does not need more to be turned over. The assumption of responsibility of the operational pain was clearly improved. The interest of the pre and postoperative treatment programs was highlighted and those Ci were also improved. The patients have thus much less fears with respect to this surgery. All this contributes to better continuations and a shorter convalescence. We should not compromise the current quality of the when one puts oneself at the invasive techniques minicomputer. Several studies drew the attention to this problem. Navigation should be particularly useful in these techniques which decreases the exhibition of the major anatomical reference marks.

MO: Where did you do yours formation?

: I was at Harvard College and the Medical School of the University of Michigan. My training of intern was carried out within the framework of “Harvard ” which was held in Massachusetts General Hospital, in ' S , in Boston ' S , and with Israel . The prosthetic articular arthroplasty that we know hardly started in the USA. Boston has a vast patient population in request for hip prosthese and knee as well as recovery. I strongly was thus confronted with this surgery. During my boarding school I am particularly interested in the relationship between the affections of the hip of the child and the osteoarthritis of the adult and I carried out a certain number of studies on the subject. One of this work made it possible to identify the deformation of the femoral head in “stick of gun” like a precursory sign of a osteoarthritis of hip. This deformation is in fact the origin of pitch badly of conflict which one operates today. After my boarding school, I made a in Toronto at Robert to look further into the relationship between the affections of the hip of the child and hip osteoarthritis of the adult. This study with conduit with the focusing of the classification of used to provide for which consecutive deformation with this disease is likely to lead to hip osteoarthritis. I also led several studies with on the relationship between the deformations induced by the hip dysplasia and osteoarthritis. After this , I was with the csotcina.comedic faculty of the University of Chicago. In 1981, I integrated faculty into to ensure the service of “Gasket Rebuilding Implant”.

MO: How do you see the future near to the hip prosthese and knee?

: Although it is trying to refer to the future developments implants instruments, I think that the most important projections will be done on the teaching of the surgery. And this for several reasons. Time that an intern little to pass to the block decreases particularly in the USA. There is more and more obligation to carry out a or a in a profitable way in term of time. In the 20 next years the number of prostheses to be posed will increase in a spectacular way. In the USA we pose approximately 620 440 prostheses of the knee a year and this figure should reach illion in the 20 next years. We will need more than surgeons to carry out these interventions in an effective and sure way. But much of these surgeons are suitable for carry out less than one score of joint replacements a year. It is thus necessary to find a means of forming them well and in full safety. The legal climate makes increasingly difficult the use of the surgical units as place of formation. We must consider methods to teach the new techniques apart from the and that for surgeons of all the levels. Lastly, the countries in the process of development will have an articular strong demand of replacement and the techniques of installation and their teaching will have to be reconsidered to face this need. I provide for major changes in the way in which we teach and of which we evaluate the quality of the procedures. I think that many the instruments computer-assisted currently developed for the and the will be adapted to teaching and the evaluation professional practices. The surgical simulators will play an increasingly large part in the training of the young surgeons. The role of the in the channel of care should also develop. Lastly, the total prosthesis of hip should be increasingly taught like an overall procedure energy of pre with postoperative rather than like a series of specific surgical gestures.

MO: Do you have a message for the French surgeons?

: Yes. I think that the French surgeons are very with the current of the csotcina.comedic innovations in the USA because the majority read well English who is currently the international language. On the other hand, the American csotcina.comedists often do not have any idea of what is done apart from the United States. These ten last years however, the csotcina.comedic institutions encourage the exchanges of ideas with the other countries. The organizers of the great congresses North Americans wish more and more to integrate into their program of the “foreign” presentations. It notorious and is well accepted that many innovating and interesting techniques are developed and used apart from the USA. I thus encourage the French csotcina.comedists to forward their work on our premises and some among us are ready to help them to find a platform for their presentation. The interested French surgeons can contact us.