R.S.
carried on all its surgical activity in England where it founded an csotcina.comedic school, a school of engineering and biomaterials articular around the prosthesis.
Contemporary of , it followed a parallel route marked by an absolute constancy in surgical methodology and the analysis of the results of the prosthesis.
This happy pensioner recalls us with a very British vision 40 years of an exemplary career. |
MO. : Do you always have a surgical activity?
. : Not, I do not operate any more and does not consult any more, but I continue to have a fundamental and clinical research activity. Of course I keep up to date with all that occurs to Princes Center.
MO. : Where did you carry out your formation?
. : I made all my studies of medicine in Oxford, then my boarding school and my formation with St S in London. I then made a year of csotcina.comedy to the Royal National , in 1805 0986 Then I made again general surgery and passed the examination of ( off Royal College off Suckers). I then worked during a few times in Canada, then, I went to Edinburgh to perfect my training in csotcina.comedy with Princes #DBFFFF and Royal off . I was engaged in Scotland in 1961 and I started to consult at this time there. My formation then was primarily directed towards the pediatric csotcina.comedics. I arrived at in 1963, and there I hoped to be able to open a center of the scoliosis because it was a pathology which I knew well. But it is that in , there were already three other csotcina.comedic surgeons who made scoliosis and who did not intend to give up this speciality. It thus was necessary me to give up this idea and I had to deal with the traumatology of the area, of with which is to approximately m from here.
When I arrived at , in 1963, one did not make there a total joint replacement of hip. The first total arthroplasty of hip was carried out in April 1965, it was . Thereafter, we did much in , and my interest was growing for the joint replacements, because all was to be made in this field.
MO. : Why did you choose to install you in the south of England?
. : There are several reasons and one of main being that my wife is of Sud-Africaine origin. The climate of the South-west of England is much more lenient, and she preferred food in an area where the weather is relatively warm. In addition, I sought a place where I could sail. Apart from csotcina.comedy, the sail is my second great passion. I learned that one of the csotcina.comedic surgeons was going to take his retreat with Princes . There was thus a vacant post. I postulated and I was likely to be established in 1963.
MO. : When did you start to work on the project of the Hip prosthese “”?
. : It was in 1969. The reason for which we started to work on this project is that we had analyzed the results of 350 and there were many unsealings. We told ourselves that we could not continue to use this prosthesis.
In addition, only the other choice for an csotcina.comedic surgeon in Great Britain at that time, was the prosthesis metal/metal of Boxing ring which we do not want, “low friction” of John is the arthroplasty. The main reason for which we did not want to pose prosthesis of was only 3 of the 4 csotcina.comedic surgeons who at that time posed total prostheses of hips with used an initially posterior channel and we want to continue to use this same channel. At that time, if one wanted to pose of , it was necessary to go in to learn the procedure. It was then obligatory to make an external channel with , which we always refused to do. It is there the main reason which decided to us to develop a new hip prosthese which became later the prosthesis.
MO. : With which diameter of head?
. : In fact, we used the heads of diameter 30 especially because it was a compromise between the heads diameter 22 of and the heads of diameter 41 of .
In 1969, when we launched the development project, nobody knew really which was the optimal size of the head, and the use of the heads of very small diameter and the Teflon cups was rather recent. We thus chose a compromise with the diameter m, which of course, moved away from the concept of “ friction”, but that did not appear to us to have the importance that one had granted to him up to that point. The large advantage of the heads of small diameter was that they would make it possible to obtain a cup with thick wall, and that, in our eyes, was more important than the basic concept friction.
MO. : Did you can convince ?
. : Not, but it should be specified that in 1982, there came in and remained approximately a week there.
It was very interested by the work made in the School of Engineers with Dr. Clive , and in the Department of Chemicals on the metabolism of methyl methacrylate. He wanted to also come to the with me, I thus programmed some cases in particular for him.
MO. : Which was the result of this temporary collaboration?
. : I will never forget the first intervention: the patient was 47 years a sporting trainer. He was installed in side; I was held behind of the plan of the hip, as it is appropriate for a posterior channel; was held opposite. After having sealed the cup and having positioned the femur to prepare the femoral canal, we installed the spreaders that we had conceived especially and who are very effective to erase the tendon of the average gluteus and to expose the upper end of the femur. The exhibition shows the femur since the basis of the neck, until the summit of the great trochanter and if necessary, one can approach the external party of the summit of the great trochanter. Indeed, with the prosthesis, we noted that it was essential to extend the cervical osteotomy to the great trochanter and even sometimes in the trochanter itself, so as to insert the stem perfectly in the axis of the medullary canal. I thus positioned the femur consequently. says that he wanted to come in my place to examine the femur. It made thus it tower of the table and was put in front of the femur during a time which appeared interminable to me. That however hardly lasted more one or two minutes. First of all, I did not understand why it was anxious, then I carried out what one could see in this position, with the spreaders in place, without needing to note the trochanter. Then we finished the intervention, reduced the hinge and started to suture, and tells me then: “yes now, of course, we find the trochanter! ”.
MO. : Therefore, you always preserved the posterior channel and for your overhauls?
. : It is not exact to say that I never changed. In fact, I used the direct external channel among all my patients during one year, but I had to give up it because I did not obtain a as good mobility as with the posterior channel. In addition, it seemed to me that my patients had more post-operative pains than with the posterior channel to which I thus returned.
In certain cases, at that time, we used the in the recoveries, but within sight of the adaptability of the posterior channel, we had less and less indications of , and we ended up more doing it whole, except as we practice it today, i.e. a wide whenever one must extract a well or sealed stem partly distal. In these specific examples, a wide facilitates the ablation of the stem largely. But if you made that, you must take care with good the before proceeding to the impaction of the Clerc's Offices.
MO. : Therefore, for the whole beginning, it was necessary that your stem is well centered in the femur?
. : One needed that the stem is well centered in the femur, of face. We know now that is important, but that it is as important as the stem is, of profile, near to the posterior face of the femur, on the level of the cut of the neck, and that, because of the S curve of the femur in the sagittal plan. If you establish a right stem, with its upper end centered on the cut, you will have much more chances to have an incomplete cement sleeve in its former party, on 4 - 5 cm. Therefore, now, we center the stem of face well, and of profile, we take care that it is positioned more close possible posterior borders of the cervical osteotomy.
MO. : What guided you in the development of this new prosthesis?
. : That occurred in 1965, and of course, at that time, there were many things which we are unaware of, in particular all that relates to the forces which act on the femur, and we did not know absolutely anything the torsional stresses which are exerted on the femoral head. We had noticed on our and the Thompson which were all of the cemented stems with flange, that it frequently occurred a resorption of the neck under the flange. It is in fact this observation, really very banal, which led us to think perhaps that the flange did not play any part in the transfer of the stresses to the femur and that, consequently, one could eliminate it.
Another point concerning the form of the prosthesis: the doubly conical form which was adopted from the beginning as being the form most adapted for the homogeneous distribution of acrylic cement on the at the time of the installation of the stem. It was then the only reason; now, of course, we hold for asset that this double cone associated with a polite surface is one of the mailmen most important in terms of transfer of the stresses. But, we had not understood that yet at the time.
MO. : Is this from there that your studies on cement began?
. : Yes. In fact. When we began the development of the hip, we want to also improve cemented fixing. We then launched a research program on the mechanical properties of cement. My colleague, Doctor Clive was a young qualified engineer and he then studied much the various aspects of the mechanical properties of cement, and in particular the “mailman time” in the behavior of acrylic cement, which I think, was somewhat neglected in general in the literature.
We wanted to also develop methods of cleaning of the femoral barrel by washing under pressure, and of pressure injection of cement both for the femur.
MO. : Why did you choose a polite surface?
. : In 1969, that did not answer a specific principle. We had not defined completion of surface for the prosthesis, but the femoral stem was manufactured in an alloy known under the name of IN 58 J, and according to the English standard of use of this alloy in practice surgical, implant surface was to be polite. It was the single reason there.
In 1976, during the introduction of the second generation of hips, we decided to increase the section of the stem, because we had had some cases of rupture with the original alloy stems IN 58 J. We wanted to also extend the number of sizes because the original range included only 2 sizes. When this new range of stems was manufactured, it was it with a matt surface. It was not a requirement of our share, but at this time there, practically all the stems had a matt surface. In addition, the original stem “” which, I think of being able to say it, was the best stem, was polite, then, it became a matt stem. At this time there, we did not attach any importance to this change of completion of surface. We were besides very satisfied with this completion for our prostheses. It also should be noted that the manufacture of a matt stem is less expensive at exit of forging mill, that of a polite stem. The polite stem is in fact a “pre-worn” stem.
MO. : Now, everyone agrees to recognize that the surface of a stem must be polite, but which is the standard?
. : On the polite prosthesis, polishing always was of 0,01-0,icrons. On the matt prosthesis, that varies from 0,6 to 1,icrons. There is thus a difference from 1 to icrons compared to the polite stem. We preserved this degree of polishing which seems satisfactory. I do not know until where it is possible to go to reduce even more abrasion of metal.
MO. : What explains the performance of a polite stem?
. : In the light of our experiment with first of all the polite stems then the matt stems, we arrived at certain conclusions. In 1986, we returned on the polite surfaces and we changed never again. The first thing which struck us is that of 1970 at the end of 1975, we had to replace 3,5% of our original stems for a rupture of stem. It was extremely rare to revise these stems for aseptic unsealing, and it is in fact, remained rare up to 28-29 years of follow-up, in this original series of 433 stems carried out by several operators who used various acrylic cements. In surgery of first intention, there is only 2,77% of loosened prostheses. In addition, we only very seldom observed of lysis with these stems. We have some a little now, but much less than what we observed in 3 years of use of matt stems!
MO. : How did you detect the problems with the matt stems?
. : That started with an osteolysis located on the level of the femur. When we withdrew these prostheses, we noted that these matt stems were partially polite naturally by abrasion with cement. This type of polishing was very characteristic of all these prostheses and always arised same manner: it was localized on half postéro-intern and the antéro-external half of the stem. We studied these stems it has a few years and noted that when initial roughness was of approximately 1,4, the polite areas were to 0,5, and sometimes, certain areas were polite like a mirror. It then became obvious, that should besides have appeared obvious front good to us, that this process was related to the production of scrap of metal and acrylic cement. Moreover, the wear of cement a progressive increase in the inner diameter of the cement sleeve joined, involving a progressive instability of the stem in torsion.
MO. : Which were then your conclusions?
. : In very first place, surface subdues was much more likely than a polite surface to generate remains of wear because of the microcomputer-movements between the implant and cement. Secondly, there was a problem of transfer of the stresses. If you take a matt stem like the aforementioned, with double cone, friction with the interface implant-cement is important, consequently the ratio compression shearing with the interface cement-bone, is weak. In the case of a polite stem, friction between the stem and cement is weak, the ratio compression shearing with the interface cement-bone, is high.
There is another point which was highlighted only very recently, following experiments carried out at Oxford by an Australian csotcina.comedic surgeon, which remained here as “” there is that 3 years, for one 4-onth duration.
One of the points which he studied is the behavior of the fluids to the interface implant-cement. It showed that even when the interface stem matt-cement is perfect, a fluid can enter in this interface as well partly as partly distal, probably by capillarity. With a polite stem, this phenomenon does not occur. He studied various types of cones in matt and smooth completion. One of its most interesting experiments consisted in inserting matt and polite conical stems in cement, according to a technique guaranteeing a perfectly homogeneous cement sleeve, then to break the interface stem-cement, to replace the stem in cement of origin, and then to install the unit on an experimental operative paragraph making it possible to pressurize of the fluids the interface stem-cement. It then showed that under the pressure, once the stem had been loosened, the fluid entered between cement and the stem, whether those is smooth or matt. It measured the volume of fluid passing in the interface during a fixed time, and it calculated the flow per unity of time. The aforementioned was definitely higher in the case of a matt stem. But most interesting is still that when he exerted a stress on the metal cones, the fluid did not pass to the interface smooth cones any more, contrary to the cones chechmates, or there existed always an interface permeable metal-cement.
MO. : Which are then the clinical effects?
.: We think that this confirms the clinical observations which we have make there is more than 15 years now, concerning the specific ruptures of the cement sleeve which we sometimes met with the smooth stems. On our initial series of 433 stems, we re-examined a hundred with 15-20 years, and noted 25 specific ruptures of the cement sheath of it on the whole of the series. Only 2 of them showed signs of osteolysis on the level of the site of the rupture: in a case, associated with a plastic deformation of the stem, and in the other case, a space clearly located between the face former of the stem and the cement sleeve, visible on the first post-operative radiographs. With 20-25 years of retreat, there were 49 series of radiographic radiographs available; 8 forwarded a specific rupture and not only one did not have, would be this, only one trace of lysis related to this rupture. A study made by colleagues on their prosthesis is appeared in 1988 appeared in the Newspaper off . It brings back the percentage of lysis associated with these rupture specific with matt stems to short flange which accounted for approximately 40%. The conclusion that we fired some is thus that the polite surface, combined with a double cone, makes an interface perfectly hermetic stem-cement with the articular fluids.
MO. : In the event of depression, there is creation of a space between the prosthesis and cement, consequently, how the passage of the fluids can be stopped by a polite surface?
. : I think that all depends of course on the geometry of the stem, but in fact, one can only recognize the fact: the depression of this type of stem does not destabilize absolutely the prosthetic system. It is completely different from what occurs with a conventional stem. The phenomenon was shown in our laboratory. If you mount a prosthesis on a testing machine, the stem being inserted in cement and being forwarded to charges, and that you measure the depression of this stem in the cement sleeve, you note that after each depression, so that the stem is inserted more deeply, it is necessary for you to increase the charge. Therefore, the depression does not destabilize the couple cement-prosthesis, on the contrary it has a stabilizing negotiable instrument, it is the function even double cone.
It is also interesting to study the importance of this depression which we know since approximately 1972. We then noted that these polite stems with double cone were inserted slightly in cement and that this was far from visible on the radiographic radiographs.
With regard to the studies made on the migration, each one knows that the ( Study) brought another method of measurement of the migration. A depression of, let us tell more than 1,m or m during the first two post-operative years have a poor prognosis. Conversely, if there is no depression, it is considered that the result is good. They are only these two last years that methods made it possible to make the distinction between the depression of the stem in the cement sleeve, and the creep of cement in contact with the bone. 5 studies carried out on the prosthesis “” to date show the same thing. The stem is inserted rather quickly in cement from approximately m during the first year following the intervention, then more slowly during the second year. But this depression of the stem in cement is associated with no movement with the interface cement-bone. The 5 studies confirm it. It is there an interesting discovery concerning the cemented stems. There does not exist absolutely any movement, even over the first nths, with the interface cement-bone. Since this fact is admitted, it is not difficult to understand why this specific type of stem is seldom revised for unsealing.
MO. : How a piece of metal can be inserted in a cement sheath?
. : Here is a crucial question to which we had to answer in 1971. I remember very well the patient, woman a 56 years old, very active, who had undergone an arthroplasty with stem “” original, polite, and had a completely “forgotten” hip. Its radios, in approximately 1onth, showed a depression of the stem in cement of approximately 1,isters C' is the presence of an edging which enabled us to detect this depression above the shoulder of the prosthesis, between the implant and cement, in area 1. There was no edging with the interface cement-bone. When I saw that, my initial reaction was to think that the layer of cement had had to break. I discussed it with one my colleagues engineers. I really wondered if it were necessary to continue to use the stem. But, have regard with the clinical excellent results of this patient, and to the good aspect of the interface cement-bone on the radiographic radiographs, we thought that if cement had actually burst, and we really thought that it was the case, thanks to the form of the stem, the cement fragments had been plated against the walls of the channel under the thrust of the stem, and that stabilized the stem just like the blocks of the engine pylon of a sailing ship stabilize the engine pylon on the level of the bridge.
We remained on this idea until I operate a patient forwarding a rupture of the neck of the prosthesis. We thereafter noted that on the 433 polite original stems that we had established, approximately 95 had undergone an excessive machining with the basic level of the neck, on his postéro-external party. On the whole, we had 16 ruptures on this level. I operated the majority of these hips which forwarded a true aspect of fracture under-capital. The majority of these stems had been inserted more or less deeply in cement: 1,2,3, or isters Donc, the occasion to go to see what occurred in these hips which had functioned perfectly well until this incident which required the reintervention was to some extent a chance. There still, we noted that the interface with the upper end of the femur was in perfect continuity.
To extract the stem “”, the surgeon must remove cement on the level of the shoulder of the prosthesis; then, a blow of mallet actually applied to the head or the neck of the prosthesis is enough to loosen the prosthesis. It is not difficult to extract. When I withdrew these prostheses, I carefully cleaned the interior of the cement sleeve by washing, aspiration, drying, and examined the interior of the sleeve using a source of light with fiberoptics: I never noted the least slit in the layer of cement.
MO. : Is this really also easy to extract a cemented stem?
. : Yes, it is really easy. When you establish the prosthesis, there is generally a little cement which recovers the upper end of the prosthesis, and I think that it is not useless, first of all because thus, you can note the depression of the stem, and secondly, in the event of luxation of the prosthesis, which fortunately is very rare, during the reduction by external handling, you are not likely to make leave the stem the femur. I have in fact assisted with this type of incident with other types of stems of this kind where cement did not recover the shoulder of the prosthesis. Therefore, I confirm that when you eliminated cement which recovers the shoulder of the prosthesis, 1 or 2 skilleds of mallet is enough to release the stem of the cement sleeve.
MO. : Did you already on the occasion to reseal a stem in an intact cement sleeve?
. : Yes, we rather often did that here. One of the reasons is that we must sometimes take again stems on matt surface with a loosened cup. In this case, or even in the case of a polite stem with loosened cup, we prefer to extract the stem to facilitate the resumption of the cup. Of course, it is much more difficult with a stem on matt surface than we replace systematically by a polite stem. In this case, one bores the cement sheath so necessary, partly distal, or even it is milled, if necessary, one adds a little cement, and one inserts the prosthesis. It is extremely easy to realize, and that goes very well.
MO. : What can you tell in connection with the “”?
. : After having examined 2 or 3 of these cases of rupture of stems which had been inserted in the cement sleeve, and not to have noted any rupture of the continuity of cement, we admitted that there was obviously another mechanism intervening in the depression, and that it could wellbeing the mailman time which acts on the behavior of acrylic cement.
An important work was carried out here, at the school of engineers, on the behavior of acrylic cement. Two made important discoveries one: 1) as each one knows, cement has a greater viscoelasticity at body temperature than to the room temperature. It is as probably much in vivo higher as in vitro at the time of the phase of polymerization, perhaps because of the presence of greasy tissue in the medullary canal; 2) during the 2-3 last years, we discovered, by studying on models of standard hip the phenomena of depression of stem and the behavior of cement, that an experimental model of study cannot give a realistic idea what in vivo does without. Let us take a charge implemented, tell to g during X million uninterrupted cycles; this type of regime of charge is never found in a human organism, because the human being has one period of sleep, and when it lies down, the charge which is exerted then on its hinge is considerably reduced, even null. Even at the time of the current activities, during the day, the charge is sometimes very reduced. Consequently, a model must reproduce the diagram of the stresses supported in vivo, because they are the periods of discharge or reduced charge which make it possible to slacken the stresses on cement; it is thus a phenomenon directly related to time. The problem of the experimental model is due to the fact that, the stresses on cement do not have time to be slackened. We are convinced that the viscoelastic behavior of cement has a great importance in the operation of the hip prosthese.
MO. : When did you start to use the techniques of impaction of Clerc's Offices?
. : I used the technique of impaction of endo-femoral spongy Clerc's Offices 2 or 3 times, without cement addition, between 1984 and 1986, including once at the time of a bilateral joint replacement. The patient is later on deceased of disseminated . The third case was a completely asymptomatic patient after the intervention, with good pushes back osseous on the level of the femur, but whose stem was inserted all in the femur gently. The patient refused the reintervention.
These some cases, in the light of the experiment of Thomas on the slope , led us to test the technique of impaction of Clerc's Offices with femoral sealing. The first case was carried out in May 1987.
MO. : Do you use the technique of impaction of Clerc's Offices for all your cases of overhaul?
. : I do not operate now any more, as you know it. But I can say that this technique is used in the majority of the cases operated here. There are some cases, I think, which could be resealed, but in the very large majority of the cases, one uses compacted Clerc's Offices.
MO. : With this technique, the cement sleeve is very thin. Do you think that can be a source of problems?
. : Not, I do not think. I base myself on our experiment of the polite original stems established between 1970 and 1975, in which the layer of cement, under the negotiable instrument of wear, had become very thin - and in fact, at half of these patients at least, the cement sleeve was incomplete - and they do not have, to date, no problem.
MO. : Did you already use massive ?
. : Yes, we used some massive on the level of . We forwarded this experiment to the Congress EFFORT. We very seldom used only massive on the level of the femur, and I think that still remains very rare today.
MO. : Where is your tissue bank located?
. : The tissue bank is here, at the hospital. The bone tissues are preserved in a freezer at the temperature of - 70° C.
MO. : Do you practice certain tests to check the absence of virus?
. : Yes, of course. All the samples taken at the time of an arthroplasty of hip of first intention, with the agreement of the donor, are first of all forwarded to a tracking; the patients undergo the test for AIDS, Hepatitis B etc… The samples undergo bacteriological tests. It are then placed in part of the freezer reserved for the femoral heads “on standby”. Six months later, the patients Re-are tested. If the test for AIDS is always negative, the femoral heads are then transferred in the party of the freezer of the heads “ready with employment”.
MO. : This is you who developed the system X-Changes?
. : The instrumentation was developed jointly by the “engineers house” and the surgeons of , it is a very promising system.
MO. : Let us return to your standard stem, you amended it while making it modular and by amending lateralization. Why did you amend the original stem?
. : The lateralization of the most used current stem is of 4m, and it is the same one as that of the original stem “”. In fact, only the large difference between the current stem and the initial model are that the section of the current stem is slightly broader than that of the original model: and the fact that the shoulder is now curved at the external edge of the prosthesis. This specific amendment was made with the idea increase the rotation stability of the stem, like its rigidity partly . We seek to obtain a better transfer thus stresses. The current stem has a section slightly broader than the model of our beginnings which missed resistance; indeed, as I said, we had 3,6% to 4% of rupture of stem to date, with this steel model IN 58 J. Of course, the current stems are manufactured in a more resistant alloy, nevertheless, we thought that it was necessary to strengthen the upper end of the stem. The other reason was that we often observed with the first polite stems a plastic deformation on the posterior face of the implant. We also sometimes observed it with the matt stems, slightly more massive than the original model, polished, but whose alloy, of the 316 L, was much less hard than that we currently use, .
With regard to the modularity, we realized in 1988 whom there were many elements which played in favor of a head of smaller diameter than isters We want to thus use a head of small diameter, and at the same time, we needed the modularity bus of the thousands of cast solid prostheses on matt surface with a diameter m had been established. Some were going to return with a loosened stem but a cup fixed perfectly well, therefore we needed a stem with which we could use a head of diameter isters Cela proved to be necessary during the recovery.
MO. : Do you use ceramic heads?
. : Yes, we use the ceramic heads with the systems, not so much here, in . The problem is that they are expensive!
MO. : What do you think of the prostheses to measure?
. : In my opinion, the prosthesis to ideal measure is a cemented prosthesis established with a good pressurization of cement for marrying the form of the medullary canal well. I do not think that there exists a method of manufacture of prosthesis to measure which makes it possible to adapt also precisely to the internal morphology of the femur, that can make it a cement sheath.
MO. : And with regard to the medullary extra party of the prosthesis?
. : With regard to the amendment of the prosthesis in terms of and lateralization, one can consider that it would be of course the ideal. However, because of various lateralizations and lengths of neck offered by the range, the possibilities of lateralization are practically unlimited. As regards the , it is different; we never chose prostheses right or left , mainly for reasons of inventories and cost, but obviously if you have the possibility of the stem, you must take care to preserve a complete cement sleeve.
MO. : In the same order of idea, that do you think of the prostheses without cement?
. : It is clear for me that there are many types of very powerful prostheses without cement. We chose the cemented prosthesis new version, here, in for reasons of cost, by keeping in mind our experiment of the polite stems of the Seventy, and the fact that these stems are very seldom taken again for aseptic unsealing.
In fact, in , there is a person who deals with all the files of hip which are now computerized, she has all the listings of surgical unit, as well as all operational reports. They is thus capable to ensure that no hip Universelle of first intention established with Princes was included in this same hospital. This does not want to say that there no were recoveries carried out elsewhere, but it is really very rare to take again a stem for unsealing. Studies showed the reasons clearly of them. We thus never felt the need to use the hips without cement in consequence of failures of our cemented hips.
There is another aspect to consider: the stem is structurally relatively rigid, and the femur is structurally much less rigid. It is not thus perhaps a bad thing to have, between the very rigid operative paragraph and the operative paragraph much less rigid, a layer made in a material of an intermediate level of rigidity. Cement can of which to have certain advantages that we do not even apprehend yet; the negotiable instrument of amortization can be another advantage, and in particular viscoelasticity.
MO. : In your series, you show that your stems have very a long life of life, and that you have some resumptions of cups. Are the hybrid prostheses, for you, a solution?
. : In our initial series of polite stems of the Seventies, 22-25 years from retreat, 7% of the cups were included. The cups any polyethylene which were offset (inner diameter compared to the external diameter) did not have a good durability. We know that the technique of sealing of the cups improved well; we think that there is still progress to make and that the cemented cups any polyethylene have very to gain there, even if today, the majority of the surgeons use cups without cement. There is perhaps less cemented osteolysis with the cups any polyethylene, if sealing is well made. But I must admit that the current models of cups without cement are very powerful up to approximately 15 years, and I would not even seek to argue with somebody who wants to make at all costs without cement, even concerning the stems.
MO. : Let us speak publications: which is the difference between the Britannique and American?
. : The editor association of the Britannique is a friend. For me, it is clear that what it publishes in this review, they are items that people have desire for reading, who deliver a message. In addition, papers are not too difficult to read and they are never very long. The review is very user-friendly.
In the American , you have very complete reviews of certain series of hips for example, but I must admit that the items require sometimes a very careful reading. I think that it is the great difference between the two.
MO. : Did you publish much in the American ?
. : We did not make publications in the American version. In fact, I would hesitate to address items following the experiments to them which I had with other American reviews. Indeed, our experiment of the hip here, and all that relates to the depression, and the mailman time in the behavior of acrylic cement, etc… all that is so foreign with the “Kantian” spirit very of the Americans whom I think that it would be even difficult to lead the readers of this review to accept that what we say is an established fact. The American csotcina.comedic surgeon is conditioned, and with regard to the cemented hips for example, he considers that certain things are sacrosanct: flange; centrifugation of cement, crosses preliminary, and when someone else claims that there exist other manners of proceeding, it does not admit it readily.
MO. : You took part at many medical committees. What do you think of the National English?
. : Here is a quite delicate question. The NHS is, or became, which one calls in Great Britain a “cow crowned”. It is a very popular organism near the general public because people have the impression that if it arrives to them something, if they in the street, one is reversed will deal with them. Quite simply, they do not want to hear of the least change in the system of gratuitousness of the hospital care. Large numbers of people recognize perfectly the implications of such a policy because of the situational change: increase in the proportion of elderly in the population, increase in the types of operation as well medical as surgical suggested. Of course, the politicians carry out the dance. In this new context, to continue to ensure of the hospital care free and unlimited the population, will not be obviously soon more possible. I think that there will have to be changes, and these changes are announced very difficult to realize in England. The more they will be pushed back, the more they will be difficult to implement. It is now a political problem, but there currently does not exist any politician in Great Britain which would go so far as to dismantle the system of gratuitousness of the hospital care, because they consider that does not deserve to bring into play a whole political career. Therefore, I think that big troubles await us, and when one considers the quantity of medicines which arrive on the market, drugs resulting from genetic engineering, the costs are enormous, and I do not see how that can to continue thus, in particular if you add to it all the range of existing surgical operations, which go well, without same speech of the experimental surgery. I think that early or late, more and more of people will have to put the hand at the crucible and to contribute a greater share to the system, and I do not think that must pass only by the tax.
MO. : For you is the hip arthroplasty a surgery of need or comfort?
. : I think that in the majority of the cases, the total arthroplasty of hip is necessary. It makes it possible to the patients to become again active or to take again an occupation. There are many farmers in this area who would have been constrained to sell their exploitation if they had not been operated. Thus, I do not think that it is about surgery of comfort. However, I think that certain patients are petitioning whereas they forward only light symptoms. In this case, if they manage to convince a surgeon to practice the intervention, have can then consider that it is surgery of comfort.
MO. : Which is, according to you, the future of the hip prosthese?
. : Perhaps to very long run, one will turn towards the molecular biology which will make the intervention useless, except in the event of traumatism, and it will be a very great progress there. But of course, it is not for tomorrow.
As regards the immediate future, I think that it falls to the csotcina.comedic surgeons to make sure that the interventions are practiced by experienced operators, having an high level of technical skill. I think indeed that a certain number of problems encountered in the past, and in particular unsealing, are the consequence of technical errors. Studies show that the early failures mechanical are directly related to what occurred on the operating table. It is very important. I think that the young and active patients must be operated in centers where exert very experienced surgeons.