M.O. Could
you tell us something about yourselves?
J.C.
Cartillier. I am an orthopaedic surgeon, working in the Lyon region,
at a private clinic that also treats patients under the State health
care system; I do general orthopaedics with an emphasis on hip arthroplasty.
J.P.
Vidalain. I, too, am an orthopaedic surgeon in private practice,
and was trained at Lyon. I did my specialty training under Prof. Georges
de Mourgues, and it was probably during that time that I felt the call
to go into hip surgery. I left the public hospital in 1976, to open
up a practice in Annecy, where most of my work is hip and knee surgery,
with more or less equal proportions of arthroplasty and sports surgery..
M.O.
All of you are from Lyon?
J.C.C.
Yes, we all went to the same medical school. We have known each other
since our undergraduate days, and started our specialty training together.
We trained under Trillat, Dejour, and de Mourgues. The other members
of our group are Bruno Balaÿ, Louis Setiey, Jean-Marc Semay, Claude
Charlet, and Alain Machenaud. We all work in the Rhône-Alpes region.
M.O.
What prompted you to set up ARTRO?
J.C.C.
Initially, we were just a group of friends, who had studied and trained
together. However, a couple of years after going into practice, we each
started feeling very lonely and isolated, so we got together to pool
case notes, to travel, and to run a journal club.
J.P.V.
Yes, we would meet regularly during the Lyon Hip Seminars that Georges
de Mourgues used to organize almost every year. In 1980, after a day
of lectures, we were sitting together over a few drinks, and we realized
that we were all alone, with each one working in his own little corner.
So we thought we should form a little club, whose sole ambition was
to get some pals together so they could have a mutual moan about their
professional problems. The meetings were generally held once a month,
and as it happened, virtually all the questions had to do with hip surgery.
Right at the beginning, the Climo company provided us with a venue in
Lyon. This company had already set up something like a foundation, and
they let us have a meeting room with some X-ray viewing boxes.
M.O.
So you found that meeting at conferences and seminars was not enough
...
J.C.C.
I think our meetings complemented the seminars at the hospital. The
seminars in Albert Trillat's department, for example, were very formal
affairs, with a vertical structure, whereas we needed a horizontal structure
that would allow more of a free exchange of opinions and ideas, and
- most importantly - where we could travel. We wanted to discover the
world of orthopaedics around us, which is why the original working group
also grew into a travelling group.
M.O.
Orthopods have always been able to travel singly; so why this idea of
going around as a group?
J.C.C.
Travelling by oneself is quite different; abroad, and especially in
the English-speaking countries, it is probably better to travel with
colleagues.
J.P.V.
Yes, you are received much better if you arrive in a group: your hosts
feel a bit more of a need to organize something, and will do more than
they would lay on for just one visitor. Travelling as a group, we have
always been very well received, and also got more out of our trips:
different members of the group would have understood things differently,
remembered the "message" differently. So, when we got back
and had a debriefing session, we would benefit from the views and recollections
of all the group members. That, in fact, is the strength of the group.
This potentiating effect became very important when we started thinking
together about practical projects.
J.C.C.
We very soon came to focus on hip replacement. Each one of us was using
different implants; however, when we asked ourselves whether we were
happy with what we'd got, the answer was always, "Yes, but ..."
Each one of use had his own very specific ideas of what an ideal hip
replacement should be like. We were lucky in that we could pool our
ideas within the group. Any ideas put forward by one member would, of
course, be criticized by the others; however, none tried to impose his
own point of view on the other members. This is why, unlike the proverbial
committee, we did not try and design a horse and come up with a camel,
but discussed and argued our way through to a hip replacement that embodied
all the improvements and enhancements that had been suggested by the
various members, and accepted by all the members of the group.
M.O.
There was, of course, the risk of finishing up with the least common
denominator. Many groups were unable to do something innovative, because
they were being too "democratic" ...
J.C.C.
Well, in our case, the chemistry worked. Our way of working has proved
efficacious over the years, so we saw no reason to change the formula.
Until very recently, we would not hear of changing the structure of
the group, even though we had been asked to admit some of the big players,
from the universities or from abroad. We always said no. In practice,
groups that have been artificially put together by the manufacturers
are unmanageable and unproductive; often, they are nothing more than
a commercial alibi.
J.P.V.
We never had a group leader. Any suggestion made by a member of the
group would be analyzed in detail by the other six, and that was never
counterproductive. On the contrary, it allowed us to choose wisely:
we never got it badly wrong when making our policy decisions.
M.O.
You are seven very different personalities, and even with the greatest
mutual respect, you could have had major disagreements ...
J.P.V.
Yes, we are all very different persons, and we work very differently:
we have different approaches; our biomechanical concepts may be rather
different. However, we sat down together in the 80s and tried to establish
the specification of what we, collectively, thought the ideal hip replacement
should be like. The progress we made during all those years was perhaps
due to the fact that we had never given in to commercial blandishments:
we felt that what manufacturers wanted was not necessarily what we had
opted for. Many groups that were united only around some commercial
project have not lasted. Our group started from the - perhaps somewhat
naive - idea that we would work together as friends; we did not set
out to create a range of implants. When the whole thing became a success,
each member of the group was able to make his input within the group
as a function of his personality and his specific skills - fundamental
science, journal club, clinical trials, statistics, PR ... Everyone
found something to suit him.
J.C.C. Between our first meeting and our first draft for a hip replacement,
there was a time of two years. The Titan THR was born in 1982.
M.O.
How did you see hip replacement at the time the group was set up?
J.P.V.
Georges de Mourgues was a dedicated follower of McKee: the first McKee
was inserted in Lyon in 1969, and de Mourgues remained faithful to this
pattern ever after, even though he later gave up the metal:metal combination.
He sent me to England in 1972. I spent some time over there, first with
John Charnley, and then with McKee. I still remember very clearly how
I was struck by the different culture at those two centres. Charnley's
hospital was like something out of science fiction or the space age:
surgeons wore space suits and worked in laminar flow theatres. The research
labs were next door to the operating theatres, and the engineers would
be in theatre every day. The team itself was pretty international by
then. McKee's universe was totally different. From the operating theatre,
one could see the countryside, lots of green fields. He would do just
one or two procedures a day, then have a cup of tea and some biscuits,
and go off to play golf. I rapidly realized why my chief was so much
on McKee's wave length. One thing I learnt there was the anterolateral
approach, which McKee did wonderfully well. I am still using it, on
an orthopaedic table; and it is also used by two other members of the
group. However, that's as far as I went in following McKee. By the time
I was going into practice, I was no longer using the McKee prosthesis.
Like most of the other members of the group, I had gone over to the
Charnley-Müller. That, basically, was our philosophy at the time.
J.C.C.
Yes. Most of the hip replacements in the early 80s were nonmodular cemented
devices. Cementless arthroplasty was still in its infancy, producing
largely disappointments. In the private clinics, we had to use implants
of proven merit. Almost all of us would use the self-locking pattern,
and when we came to think about possible improvements, we were starting
from Maurice Müller's device, wondering how it could be given enhanced
stability. The idea was to develop the "sabre blade" of the
self-locking prosthesis, to get 3-D stability by introducing an ap and
lateral flare in the metaphysis. From this flare in two dimensions came
the concept of 3-D stability, which is the great achievement embodied
in the Titan.
M.O
Was that your first baby?
J.C.C.
Yes.
M.O.
What were the features of the Titan?
J.C.C.
Firstly, it had this original ap and lateral flare in the metaphysis.
Secondly, there was the material - forged titanium with a smooth anodized
surface. And, thirdly, it was modular, with a neck taper that accepted
heads of different diameters (22, 28, and 32 mm), and allowed different
head-neck lengths; above all, modularity made it possible to introduce
alumina ceramic as a material.
M.O.
Had you also taken care of the offset?
J.P.V.
Not initially. However, we were well aware of the importance of preoperative
planning, a subject much emphasized by Maurice Müller and the AO.
Offset was not a major concern in those days, but we soon found out
how important morphological patterns, especially coxa vara, could be;
and the Titan very quickly came out in two versions - a standard one,
and one with increased offset.
M.O.
Who made the implant for you?
J.C.C.
Many big companies said they were interested in our device; however,
to keep investments low, they wanted to alter it to suit their manufacturing
conditions. In the end, we got in touch with Landanger. This company
made surgical instruments, and had a distribution network in place.
Landanger wanted to go into the implant business, and were looking for
a design group. So ARTRO and the men from Chaumont got into the Titan
venture together.
M.O.
How did the Titan perform in clinical use?
J.P.V.
We were completely happy with how it did in clinical use, otherwise
we would not have gone on.
J.C.C.
I am still using it, and the Titan has remained unchanged, because we
were lucky enough to get the shape and the surface right first time
round: we had opted for forged titanium with a polished finish, so we
did not run into the corrosion and the osteolysis problems that different
surface finishes could have produced. As with any design, it is vital
to keep the shape, the material, and the surface finish together as
one concept.
M.O.
How was it received by the orthopaedic community?
J.P.V.
At first, it was not that widely used. It was a device for use by the
ARTRO surgeons. Also, it had not been patented, so we were not financially
involved. The group members did between 700 and 800 implants a year.
Then, Patrick Landanger asked us to allow him to offer the Titan to
a wider circle of users. Since we had validated the design over a long
period, we agreed. This was the start of the wider use of the Titan,
both at home and abroad. It went on performing well over the years,
and we were very pleased to see it figuring recently among the "top
ten" of the Norwegian hip implant register, ahead of the Charnley
- but level-pegging with the Corail.
M.O.
Why did you turn to cementless arthroplasty?
J.P.V.
Not because we were dissatisfied with cementing, nor for any commercial
reasons. In fact, when we came up with the idea of a cementless implant,
our manufacturer was not an entirely happy man. Back in 1985/86, there
was a lot of talk of "cement disease." It was thought that
the failures of cemented implants were due to the cement used, that
the cement did not age well, that it fractured, that it produced granulomas,
that it was responsible for corrosion, etc. It was, therefore, tempting
(if a bit simplistic) to try to get rid of all these problems by no
longer using cement.
M.O.
So how did you go about it?
J.P.V.
The in thing at the time was porous metal. So we went to the States,
in early '85, to go around and see right there and then what porous
metal could do. This trip left us moderately enthusiastic. On the flight
back, we were reading a fundamental-science journal, and chanced upon
a little article on hydroxyapatite. We figured that if one could get
this material onto an implant, one might have found an answer to the
question of "biological" fixation. Some time after our return
to France, we mentioned this line of research at a group meeting attended
by Patrick Landanger.
J.C.C.
He had already suggested to us a strange material called Proplast, for
which his company had become the European distributors. The original
fixation principle of Proplast was by promoting the formation of a fibrous
layer around the implant, to act as a shock absorber to the prosthesis.
The Group discussed this idea, and, nipping any run-away enthusiasm
of individual members in the bud, absolutely vetoed this "innovative"
idea. However, to come back to the possibility of coating the implant
stem with hydroxyapatite: the problem was that nobody had managed to
apply such coatings other than by hydrolysis, which was totally unsuitable
for orthopaedic purposes. So we were stymied.
M.O.
So what did you do?
J.C.C.
Patrick Landanger at long last found out that there was a university
laboratory in Germany that was working on the application of hydroxyapatite
using a plasma torch. He negotiated with them, and got them to try out
the coating of Titan implants that had had their smooth surface finish
removed, and which had been grit-blasted to provide a key for the HA.
J.P.V.
We didn't know it at the time, but there were two other groups working
on HA coating: Ronald Furlong in England, who, incidentally, was having
his first stems coated by the same university lab in Germany, and Rudolph
Geesink in Holland. So, quite by chance, and without knowing of each
other, there were three groups who started out in '85, and who were
having their first implants HA-coated almost on a jobbing basis.
M.O.
How did you perform your clinical trials?
J.P.V.
We had a short run of HA-coated implants made, and then we inserted
them. What we had was the basic Titan, but with a different surface;
we called it the Titanapatite. It may sound funny nowadays, but that's
how things were then: no acceptance procedure, no CE label. In actual
fact, we were not running too many risks. HA was a substance that was
known and had been used in patients, especially in maxillofacial surgery,
where Osborn had pioneered its use back in 1976. It had been used as
a space filler, and it was known to be nontoxic, not to give rise to
inflammation, and not to be carcinogenic. What was new, and unknown,
was its use in a thin layer. Our animal studies had shown that a titanium
body coated on both sides with HA did not become ensheathed in fibrous
tissue when implanted into the iliac wing of a dog. The implant was
not recognized as a "foreign body." So we implanted our Titanapatite,
and were delighted to see, right from the start, the total absence of
the clinical problems with which our earlier cementless replacements
had been fraught: there was no thigh pain, even with immediate full
weight-bearing; these cementless implants were behaving exactly like
cemented ones.
J.C.C.
The initial series consisted of 70 implants, which meant that each one
of us was doing ten. We've always had this habit of doing everything
the seven of us. At all the meetings, there is the seven who turn up;
in a discussion, there is the seven who argue; we work a lot, but it's
always the seven of us.
M.O.
You have famous predecessors - the seven dwarfs in the Snow White story...
J.C.C.
You're right - but there is no Grumpy, no Sneezy, and, from what we
can tell, no Dopey. Well, as I was saying, we did our first series,
and found that the patients had absolutely no clinical symptoms, and
that the X-rays were like nothing we'd ever seen: bone had grown to
fill the space between the cortex and the implant. We followed the patients
up for one year, after which we felt that HA had proved its worth. This
new biomaterial struck us as vastly superior to all the beads and all
the surface finishes we had known before.
M.O.
Did you consider changing the shape of your implant, for cementless
use?
J.P.V.
Certainly. It was very clear to us that for biological fixation to occur
the implant had to have perfectly stable. We were very happy with the
primary stability of the Titan, but we thought it was vital to have
a macrotextured surface for the cementless prosthesis. We had umpteen
meetings, at which each one of us presented his prototypes, his drawings,
his plaster, plasticine or carved models; and we eventually decided
that what we wanted was horizontal grooves in the upper, metaphyseal
portion, to prevent subsidence, and vertical grooves in the femoral-shaft
portion of the stem, to protect against rotatory stresses. The transition
zone between the two portions was to receive special design consideration.
This pattern was approved by all seven group members. The only point
on which we were not unanimous was the collar, because there were equally
many arguments for and against having one. So, to be fair, we had the
device made in two versions, with and without a collar. This way, the
advocates of either design could see how it all worked out in practice,
leaving the decision to a later stage. However, the matter has not been
settled yet: our figures have not shown either version to be clearly
superior, even if each one of us feels in his heart of hearts that his
is the right design.
M.O.
Whose idea was it to have grooves going one way at the top and another
way at the bottom?
J.P.V.
Jean-Claude.
J.C.C.
The difficult bit wasn't having the idea, but persuading the others
that it was valid. Nobody knew what the fate of HA would be over a period
of ten years, whether the coating wouldn't be here today and gone tomorrow.
The bone newly formed in the healing process had to be able to reach
enough projections to establish an intimate contact. And since we were
still very concerned about such questions as implant subsidence and,
above all, rotational stability, we added grooves to the original pattern.
Fifty designs were presented and rejected before, at last, the group
gave its blessing. The important thing was not to have microgrooves;
neither did we want a saw-tooth pattern. Also, the whole thing was supposed
to look attractive, and the implant had to be feasible from the manufacturing
point of view. The most astonishing thing was that our histologist,
Patrick Frayssinet, found that these grooves were hugely beneficial.
He showed that most of the bone formation takes place on the crest and
on the sides of the ridges.
M.O.
When was it launched?
J.P.V.
In '86. It was first used in a patient in September of '86. We called
it Corail, because "coral" makes you dream of South Sea islands,
and because both coral and synthetic hydroxyapatite are made up of calcium
phosphates that are very similar to the mineral phase of bone, both
chemically and from the point of view of crystallography. All these
substances are apatites. It's not natural coral, but the HA coating
resembles the substance that coral is made of. And this time, we took
out a patent!
M.O.
Where did you go from there?
J.P.V.
We did not rush things. The first year, we did only a small number of
implants. The patients were selected in the light of their age, the
quality of their bone stock, the shape of the femur. When we were a
bit further down the road, these criteria were abandoned. We developed
a whole range of stems. We also had to design a metal-backed cup with
a hydroxyapatite coating, and, in order to suit individual preferences,
we provided two types of press-fit sockets: a threaded and an impacted
one. We had, for quite some time, been very much in favour of threaded
cups, but this pattern was not in then, and there were many opponents
of threaded cups, who cited the disastrous results produced by threaded
rings that did not provide for bone ingrowth. We were also working on
specific devices for revision arthroplasty, which was becoming a more
frequently performed procedure. What we wanted was a comprehensive,
consistent Corail System, all based on the same concept.
M.O.
What sort of head did you choose?
J.P.V.
The Titan implants had a 32-mm head. For the Corail, we offered a choice
of 32- and 28-mm heads; and our preference was for alumina.
M.O.
How did the threaded cups fare?
J.P.V.
The threaded cups with an HA coating have never caused any problems.
We are therefore still strongly advocating the same threaded pattern,
which will soon be available with a ceramic insert.
J.C.C.
Threaded cups have been badly misunderstood. People tend to throw together
the different materials, shapes, and surface finishes. The surface finish
is, obviously, crucial. With our HA-coated cups, we have not seen any
substantial differences between the two patterns: it does not matter
whether prestress is achieved by the screwing-in or by the impaction
of a cup. In the long run, the two types will behave in exactly the
same way; however, self-tapping threaded cups will do slightly better.
I think that this has got something to do with the threads, the macrostructures.
In the Norwegian register, this pattern has been found to be superior
to all the other cups studied.
M.O.
How do you select your patients for cementless hip replacement?
J.P.V.
We have virtually given up cemented arthroplasty in all our patients,
since osseointegration will be brought about at any age, and regardless
of the quality of the patient's bone stock. It is a consistent, a reproducible
phenomenon. Of course, one could argue about the costs involved; from
the strictly biological perspective, however, an HA-coated implant will
be integrated as soundly by a young patient as by an older one, in osteopenic
stock and in dense bone.
M.O.
No clinical differences at all?
J.P.V.
None. That is why we do not apply any selection criteria of the sort
that Spotorno has seen fit to establish.
M.O.
What does a Corail look like after 13 years in situ?
J.P.V.
The radiographic follow-up shows that osseointegration takes place over
the first 12 to 18 months. After that, the X-rays do not change any
more. You can superimpose the 5-year, the 10-year, and the 13-year X-rays:
the space between the implant and the endosteum won't have changed one
little bit. There are no lucencies, no reactive lines, no lysis. Of
course, there is some change that takes place around the prosthesis.
In particular, stress shielding is responsible for calcar remodelling.
The edges become rounded, but there is no radiological evidence of cortical
atrophy. That brings me to a fundamental feature of the Corail: its
all-over coating with HA. We got a lot of criticism over that decision;
people said that the implant would become blocked distally, that we
would have major problems with stress shielding, that the femur would
suffer badly if, heaven forbid, a soundly fixed prosthesis had to be
removed. These prophecies of doom were based on what had happened with
the massive, rigid madreporic devices, which had actually led to major
stress shielding and were immensely difficult to remove. Nowadays, though,
it is accepted that it is not the coating as such that causes stress
shielding, but the stiffening of the implant-bearing femur. This underlines
the importance of having a tapering titanium stem that is not in very
intimate contact with the cortex. We are thus very far removed from
the concept of fit and fill. In the overwhelming majority of cases,
the Corail has not led to any visible changes in the cortex; however,
as our densitometric studies have shown, there is bone rarefaction below
the detection limit of our radiographic systems. The decrease in density
is about 30-40% in the proximal region, and we know that about 50% of
the bone mineral content would need to have been lost for this loss
to show up on X-rays. Since 1989, we have been using dual-photon absorptiometry.
In fact, we have probably pioneered the use of this technique in the
study of remodelling around implants.
M.O
And what about the Corail vs cemented implants?
J.P.V.
The cemented stems often have a smaller diameter, to leave enough room
for the cement mantle. So the whole thing is less rigid, and there will
be less stress shielding.
M.O.
How have the Titans inserted 20 years ago been doing?
J.P.V.
We have not yet reached 20 years' follow-up. We are following up these
implants, and as far as fixation is concerned, the long-term results
are very, very satisfactory, with 96% survivorship at 10 years. I have
already mentioned Norway, where they have been studying all this very
stringently and against a broad background.
The Titan's pattern over time is, of course, marked by polyethylene
wear, and the granuloma formation that this wear entails. With hindsight,
we are now realizing that our best Titans were the very early ones,
which had an all-PE cup, rather than a cemented metal-back design.
M.O.
Do you think that the alumina:PE combination is much better tolerated
than steel on PE?
J.P.V.
There is no easy answer, because a lot depends on the quality of the
PE, especially the one that was available in the early 90s. The ceramic:PE
combination made in the 90s did, in fact, suffer from inexplicable wear,
whereas this problem did not exist with the earlier PE, not even with
32-mm metal heads. We have revised some of the press-fit cups with a
badly worn PE insert, where there were major granulomas in the pelvis
and incipient granuloma formation at the greater trochanter or the calcar.
In these cases, the cup was revised, and the proximal femoral granulomas
were curetted; however, the stem was always left in situ. No Corail
stem has ever been removed - hence the widely held idea among the users
of HA that this coating constitutes a barrier to the circulation of
fluids, and, consequently, to the migration of wear particles. However,
we must not kid ourselves: the wear particles may migrate more slowly,
but migrate they do. This is why we must get the material combination
for the bearing surfaces right; and why we have opted for ceramic:ceramic.
J.C.C.
In 1990, we did a hundred or so alumina:alumina implants, with hemispherical
HA-coated cups. We then stopped the series, to see how these implants
would do. After this precautionary time out, we started again in '97-'98,
with new implants with interchangeable alumina bearing surfaces. We
think that it is safer to have an alumina:alumina combination, so as
to make sure that the hydroxyapatite does not get accused of causing
third-body wear.
M.O.
Is the present Corail stem the same as the one you had 13 years ago?
J.C.C.
Absolutely; and the coating details are the same as well. The coating
is done by Bioland in Toulouse, using an air plasma spray process to
create an all-over coating with a thickness of 155 µm. A little
while ago, we had a meeting in Malta with all the Corail users. We asked
them whether anything needed changing in the stem parameters; whether
they could think of any improvements that should be made. There was
substantial agreement that the Corail should be kept as it is, without
any changes in its shape, and without altering the nature or the extent
of the coating: there was no scientific reason for introducing triphosphates,
a bilayer, etc.
M.O.
Landanger seems to have done well with the Corail ...
J.C.C.
Patrick Landanger has done very well with the Corail. He even had problems
coping with the international expansion of his business. There aren't
many European countries where the implant has not become established.
The most difficult to convince was the FDA: after a two-year struggle,
the Corail got the OK, which made us very happy, and was a major victory
for Landanger. However, once the system took off like that, Landanger's
facilities at home and abroad were overwhelmed, and, sadly, our French
manufacturer handed the product over to an international company, Depuy,
who have since been bought up by Johnson & Johnson.
M.O.
Does this make a difference from your point of view?
J.C.C.
We started out with a small outfit, with an R&D team based at Chaumont,
who were devoted to us, responded to what we wanted, always listened
to our suggestions. Now, we are in a much bigger structure that also
has a more sophisticated approach to product development: the big company
will not launch itself into an "adventure;" they want everything
to be properly controlled and to fit in with the international policy
of the group. So, we have lost flexibility and speed of implementation;
on the other hand, we have gained in thoroughness and quality both on
the R&D and the manufacturing side. Also, our new industry partner
has the logistical infrastructure that has enabled us to move from a
French market into the international arena. We have travelled the world
lecturing, doing surgery, and conducting workshops. Over and above this
surgical experience, we have learnt what marketing and the launch of
a product are all about. And, of course, in order to defend our ideas,
we have to give papers at international conferences. This has meant
a considerable broadening of our horizons.
M.O.
Do you think that a group of surgeons starting out today could do what
you have done?
J.P.V.
Not the way we did it, no. We were lucky to be in the right place at
the right time. Lots of rules and regulations - legislation concerning
clinical trials, approval procedures, CE labelling - had not yet been
introduced, and the economic climate was favourable. Nowadays, any suggestions
that we make will produce objections from the financiers and the strategic
planners, who point to the changing economic patterns; and only when
these hurdles have been overcome will our ideas be submitted to R&D.
Of course, we want to go on developing our products, but doing so has
become much more difficult. The pattern of industry is changing, and,
worryingly, in the medium term there may be only half a dozen manufacturers
of orthopaedic implants left world-wide. The time of the "surgeon-designer"
that we used to know is now past. Also, when we talk to our American
business partners, they cannot understand how the ARTRO group could
function the way it does. They do not understand that the entire group
submits ideas to R&D. In the States, things work the other way round:
the R&D people come up with ideas, and develop a new implant, and
then they go looking for surgeons who will try out the new device and
speak up for it.
M.O.
Which raises the question of how engineers, by themselves, could look
after all the aspects involved in the implantation of a device by a
surgeon ...
J.C.C.
True, but our present-day situation is also the result of past excess.
In the 70s and 80s, the implant industry was a mad, mad world: every
surgeon was a designer, every company in France would make his implant.
There was no rhyme or reason to what was being put on the market. Of
course, having so many implants meant that there was a strong creative
spirit, because commercial gain was not the sole motivation. There was
progress being made, even though it was all a bit shambolic. And, of
course, the same criticism may be made of the big American design teams,
who have sometimes tried, at gunpoint, as it were, to make us use their
products which had been developed with every benefit of science - computer
simulations, finite elements, what have you - and which still fell to
bits a couple of years later.
Obviously, times have changed. However, I believe that the man at the
coalface - the surgeon in the theatre - is more important than the engineer;
at least as far as the implants that we know are concerned. As regards
the new materials, maybe the engineer is more important than the surgeon.
But let me make the point that we have always worked very closely with
our friends in the basic sciences, especially, at Bioland, with Patrick
Frayssinet.
M.O.
And you are still sure that hydroxyapatite is the way to go?
J.C.C.
More than ever. It is true that, initially, there was a lot of flak
from the opponents of this "magic powder;" but at least those
who criticized us took a closer look at the material. Some surgical
teams, some of the big centres that had done a lot of cementing, now
recognize the utility of HA. The latest SOFCOT symposium on femoral
component revision has confirmed the performance of hydroxyapatite.
Nowadays, there isn't a company that doesn't do research along these
lines, and does not offer a range of HA-coated implants. We know full
well that HA is not the only way to go, but it is certainly the most
original discovery made over the last 15 years, in the field of implant
science and technology. The point that cannot be too strongly made,
however, is that an implant coating is a feature that must never be
viewed outside the context of the implant's shape and material.
With implants, success is a matter of quality. Among the quality aspects
that must be assured, good preoperative planning and meticulous surgical
technique are by no means the least important.
(Transl
KRMB)
Maîtrise
Orthopédique - N° 90; 2000, January.
