The congress “ Development 2004” organized by Jacques of group and Jean-Pierre of the School of is held this month in Lyon. It is the occasion to give a progress report on the long-term results of the implementation of the principles of John . Jean-Pierre , department head at the hospital of Paris informs us of his experiment on the matter.

 

 

. : Still a congress on the “”!

: This congress is specific because we want to join together the Parisian experiment of and the Lyons experiment. We share the principle of the cemented stem and of the head of m but we have also some small conceptual differences which it is interesting to confront. In particular, on the method of cementing of the stem. In Lyon one holds with the regular cement mantle around the stem, whereas in one seeks a filling by the stem, cement being only one means of supplementing the filling. It is rather interesting to see that with two different designs, one arrives finally in the long run at similar results which are rather good.

 

. : Which are the practical implications of these differences in cementing?

: With the block, that results in a hardware which is completely different. If one chooses the method, one needs a wide range of prosthetic stem of type whereas with the Lyons method one reduces the standard number of stems and moreover one has recourse one has graters which do not remove the spongy one but which packs it. These graters have scratches and not barbs.

 

. : And in ?

: The technique consists in removing the spongy one with borers foams because one uses cement as material of fitting which should work only in compression and which must for that be based on an hard surface, i.e. cortical. An adjusted stem is thus chosen, i.e. which does not have any more macroscopic mobility after the preparation of the medullary canal and cement is intended to fill remaining space. We use cast solid stems III of and stems de which take again the drawing of the stems I with regularly decreasing rectangular section, those which have the best results of sealing to the more long run.

 

. : Are the channels of accesses identical?

: Not, they defer. We make primarily trans-trochanteric external channels and also of the channels standard or . But we make never, or almost never posterior channels. For the Lyons group, the initially usual channel is a posterior channel with respect of the pyramidal one. J. insists with reason on the joining of the capsule in end of operation, which made decrease the frequency of luxations notably, main trouble of this channel initially.

 

. : And ?

: We use a cemented of type out of polyethylene after a digging with the torque link and the strawberry. We evolved to highly polyethylenes which really appear to have a very tiny wear. It is also the method of the Lyons group. In addition among patients of less than 70 years, they use with a metal content .

 

. : Which are your results?

: On the series of , one can conclude that the perenniality of the sealing of the stem is very good. I.e. a reliability curve with nearly 90% of presence beyond 20 years. The has a perenniality which is a little less obviously because of the wear of polyethylene. Thus we are almost completely satisfied with this prosthesis to a time of a score of year but it is known well that his weak point is the wear of polyethylene, causes femoral osteolysis then. Finally it is necessary to try to keep what there is of good in this prosthesis and to abolish the mailman of osteolysis. There are certainly several possibilities. We already used the plastic Zircone couple, but an early study with three or four years that one forwarded to the EFFORT in 2003, leaves us a little perplexed because one observed small images of granuloma on . By precaution principle we stopped the use of Zirconia temporarily.

The other possibility it is highly polyethylene.

The single study already published is Swedish and would show a wear at least twice weaker than with usual polyethylenes thus it would be a very interesting gain.

We have a prospective series randomized between conventional EP and EP highly it is de realized between 2000 and 2002 whose one now has the early results which are very favorable. The quality of the digitalization and the method of measurement must make it possible to extrapolate the results on the long term. We thus hope for a wear three times less over the 20 next years. We can already say that there is no catastrophe with the new EP (neither fast wear nor rupture). The difference between the two EP for if short term (2 to 4 years), risk to be within the limits of precision of the method and he would then be necessary to give itself more time before concluding.

The other options are the couple metal-metal of which we do not have experience and ceramics-ceramics for which one has small experience. One leaves the principle of then, one keeps the stem of course sealed, but one passes to a head a little larger and with a very rigid and rather fragile , without cement, .

 

. : And results of the Lyoneses?

: They have a 5 years retreat with the heads zirconia and for the moment they are satisfied. published interesting results with the couple . For this reason the Lyons group continues the use of the zirconia head. With regard to in they have more than 10 years of retreat and they noted an important, double wear of the wear observed with a sealed simple polyethylene . This fact was highlighted in several series. The patients do not complain but being given the importance of wear one can put questions about the perenniality of these .

 

. : Which are the other topics of the congress?

: We want to tackle the social problems with the index of patient satisfaction and also the problems economic with the production costs of a total prosthesis of hip. We count for this last point on the collaboration of the manufacturers. In addition, we made a survey into the real price of one joint replacement inside an private establishment, and and of general hospitals. Thus we can know today which is the cost price of a total prosthesis of hip, the price of the prosthesis, stay of the patient, medicines. Objective of course is not to put prostheses not expensive if they go less well, but if one notes that the least expensive go as well, it is obviously interesting. In this vision of economy, we thus use many cast solid prostheses and not only in the elderly persons, with excellent results.

 

. : What is very expensive society it is the because of its mission. Isn't it damage for a university service to stick to the old methods?

: Certainly, but one can innovate well only if one makes as well the every day, if not under pretext of innovations one will connect catastrophes. The good innovations come only from one project matured reasonably starting from a daily surgery of quality. Of course it is necessary to advance, but one should not confuse the clinical research and the fundamental research. The basic research which is for example to find a couple of new friction, is surely late on our premises because there is not enough researchers, enquiring surgeons and because they enough were not formed. This basic research he would have to be promoted. For the clinical research, it is necessary to be more careful because the role of a is also well to look after people and to train the juniors well. Our clinical research negligible, is not currently centered besides on new polyethylenes and the osseous . In this field, grace in particular to the pH which manages our bank of bone, our knowledge and our use of these Clerc's Offices is not late compared to the other countries in particular the USA.

 

. : Why the basic research is at this late point?

: The problem it is that there is not in a of appropriations isolated from fundamental research. In spite of the absence of die for the surgeons one can possibly have people who are interested in it and who will work with a laboratory, with unity INSERM… On paper it is theoretically possible, but in practice it is very difficult. One needs people who really cling because it is difficult on the budgetary level, it is gate with gate and nothing is organized from the institutional point of view. I have a which is my “enquiring surgeon” who continues to make fundamental research. It did it because it went to be formed in the United States and because it can work in the laboratory of , which is a unity INSERM.
Besides it is necessary to congratulate Laurent who has to have much perseverance to install his laboratory because there is not much place like that.

 

. : You referred to the social aspects presently…

: Yes, finally what one brings while making hip prosthese to the patients. It is the question which one tries to put. Obviously, of the clinical point of view one knows: indolence, stability, mobility, but in practice one would like to measure the gain on quality of life. Do one speaks about 170 008 hip prosthese a year in France currently, what operated make some? Are they of it satisfied? That their exchange life and in what? We them surgeons suppose things, but they should be proven and it is not always easy. One already made not badly studies on quality of life and there is of them one currently, European, which is called , with the usual indices, of quality of life in which we take part and whose we will have certain results during the congress.

 

. : You tackle the problem of the recoveries?

: Of course, because let us make some we more and more. Unfortunately, let us not be we yet to manufacture eternal prostheses. There are approximately two kinds of recoveries. There has been the patient who is regularly followed, that one knows for more than 15 years and which forwards signs of wear and tear and of osteolysis. It is prevented and one it under good conditions. There is not great a deal to repair, it is a relatively simple operation, and one set out again for a turn with good performances. The other category, relates to patients not followed for varied reasons or already operated a half dozen times and which are travelling catastrophes. One tries for them to make the best possible one and that poses to us with all technical problems. In , we are very and we in general use on the level of and the level of the femur. One makes also some femoral prostheses without cement, locked with the manner of . At all events, we have the same technical limits as the others. It is problem difficult and which is not close disappearing on the following day even if the ideal prosthesis today were invented, it would be necessary nevertheless to lock all that was posed. It is to say that a very significant number of recoveries await us in the 20 years which come.

 

. : What becomes the preserving surgery?

: The field of the preserving surgery of hip narrowed considerably. Currently, that represents for me 10 interventions a year. kind, stop, more rarely osteotomy of mining area. The essential reason is that one took a great confidence in the total prosthesis of hip and today in front of a 40 years hip osteoarthritis one it is not worthwhile tells oneself to annoy the patient with a preserving intervention to make him after a total prosthesis of hip. One prefers to make an hip prosthese by saying it must last 20 years, or if there is a little chance 25. Thus I believe that there remain some osteotomies for necroses if the extent is not too large, and at people of less than 35 years surgery of reorientation of the femoral neck and stops in the hips.

 

. : What think of the osteotomies of reorientation of ?

: One did of them some and it is not easy to succeed. Then perhaps that one is not good enough. The technique of , that I went to see several times at Bern and that it came besides on our premises to make in , is very difficult. I find that it is satisfactory on a intellectual level. But it seems to me that often a varisation-stop has the same indications at the beginning, and seems it the same results too. It is not certain, it is more difficult to decide between because as always it is necessary to be placed 20 years afterwards.

 

. : Which difference there-have-you it enters your service and that which your owner left you?

: I must initially say that I had two very different successive owners and for me complementary: Michel with his great sensitivity of the patient and Marcel with his great knowledge to make surgical. I inherited a service which was disturbed by the departure of the department head who settled in a close private clinic. This specific change had effects on the nonmedical and medical personnel. The service should initially Re-have been stabilized what is established now. In parallel, it was necessary to take again the traumatology which had disappeared due to work which lasted almost three years. Now, one remakes traumatology about under good conditions. We speak today only about the hip but I remind the meeting that we preserve an important activity of knee surgery, foot and shoulder. My third objective, it is the opening. The opening, for me, it is to make our experiment of the invasive minicomputer, it is the restricted use of a couple ceramics-ceramics, or under certain conditions of locked uncemented stems. For us, the opening, that want to tell to study a new method, a new material but with a clinical study rigorous, prospective, if possible randomized. The routine use of this new method should be considered only after results confirmed the hoped advantages. That takes a certain time that one can regret, but that seems to us the security.

 

. : It is the heritage of Blackbird of ?

: I hope that we kept the main flashes of wit of Blackbird of . I.e. the rigor of the initial reasoning and then the rigor of exploitation of the clinical results. For example that wants to say that currently, unlike some, we are neither for nor against the accesses invasive minicomputer, but that we make of it a use careful and limited and that in fact the results we will determine. That implies a large respect for the patient who should not be a ground of experimentation not controlled. I think that it is what remained since Merle of . What changed it is that one knows that it is possible several to obtain a good performance and this is why there are concepts to which one holds but they are not dogmas. There are other schools which profess other ideas which should not be regarded as heretics. The others are not wrong a priori because they do not say the same thing as us. Ca it is a change with compared to what I knew he does not have there so a long time.