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Friday, February 26. 2010
The status of DePuy Orthopaedics’ ASR platform as Feb. 2010
Last fall of 2009, DePuy decided to discontinue ASR® XL Acetabular Head
System and DePuy ASR® Hip Resurfacing Platform (not available in the U.S.)
worldwide. As a result of declining demand for the ASR platform and other market
factors, DePuy is in the process of phasing out this platform to focus on the
development of next generation hip replacement and resurfacing technologies that
best meet the needs of surgeons and patients.
DePuy wants to assure patients who have been treated with a device from the ASR platform that there will be options available to them in the future should they need a revision:
· If a patient who had received the DePuy ASR® XL Acetabular Head System for total hip replacement requires a revision surgery, the acetabular component could be revised with the Pinnacle Hip Solutions platform, which would be compatible with an existing well-fixed femoral stem.
· As with any hemi-resurfacing prosthesis, including the DePuy ASR® hemi arthroplasty, a patient requiring a revision procedure would generally be treated with a total hip replacement.
· For patients outside the U.S. treated with DePuy ASR® Hip Resurfacing (not commercially available in the U.S.), DePuy intends to maintain an inventory of ASR XL heads outside the U.S. for use on compatible DePuy femoral stems. This will allow surgeons outside the U.S. the option of retaining a well-fixed ASR Cup when appropriate as part of the revision procedure.
Lorie Gawreluk
Vice President, Worldwide Communications
DePuy, Inc.
Wednesday, February 24. 2010
WHAT ABOUT NAVIGATION
Today navigation is still a tool that is not easy to use and
that needs a certain learning curve as resurfacing itself
also has.
So it is not a useful tool today for resurfacing beginners,
where it should be! It would be nice if it would be a help
at the start of the learning curve.
So can somebody with experience use it or should they use
it?
It is like doing a certain approach and having experience
with it, so it feels better and confident.
Most of the experienced surgeons do feel they do not need
it. MAYBE it could help.
BUT there are some things that have to be cleared out still
today:
*there is no correlation in most of the systems between
head and cup.
*Most of the systems only look to the head, and nobody
can tell us today what is now the best place to put the
implant
*It would be the best to use it for the cup because
there we have the most failures!
BUT AGAIN the most problems will be with females, that
easily have twisted pelvis on the table and smaller sizes,
and it is not sure it will have a big influence here.
If it is a system with preop CT of the pelvis to do the
acetabulum, the pictures are taken in SUPINE (lying down
position!). The patients walk and run on their hips, they do
not lie on them, and that can make a complete difference!
So we are not there yet, if something could help me to do
better surgery it would be navigation, but as it is today,
it is not a 100% proven project. I have today so designed
instruments that I call it navigation without navigation; of
course in other sites navigation really could help!
I do not know if the 7 malpositioned cups in my series of
3000 would have benefited with navigation, possibly yes, but
maybe would have had others where then the placement was
worse?
It is the future?, maybe, but not there yet at present for
everybody. That is why not everybody is using it, not just
because we would be to lazy, to old, to stubborn or
whatever.
If it would be used tomorrow in all cases from the start,
the worry is also there, that if the navigation fails we do
not know anymore what to do. All these facts should not be
used for marketing or publicity issues but left to the
orthopaedic community to make it better, try it and try to
succeed better, what prof.Cobb, myself and all others I
think try to do.
KOEN
koen de smet
hipsurgeon amc gent krijgslaan 181 9000 GENT BELGIUM
+3292525903
www.heup.be
anca clinic roma valle giulia ROMA ITALY
www.ancaclinic.it
Tuesday, February 23. 2010
There is some data indicating that navigation can improve
the accuracy of femoral component placement in hip
resurfacing. The real issue is "compared to what?" For an
inexperienced surgeon, navigation may help him avoid
component positioning problems that have been associated
with "the learning curve". However, for an experienced
surgeon, who has an established mechanical alignment system
with a high success rate - it is difficult to demonstrate an
advantage to him with a navigation system. Further, the
registration process takes a little time – so the
cost-to-benefit ratio for the experienced surgeon in a busy O.R. is questionable. The navigation systems are not hard
to learn to use, even for old guys like me!
A bigger challenge is acetabular component positioning.
This is true for total hips, and even more important for
resurfacing. There are 2 parts to the acetabular
positioning problem. The first is identifying the desired
position for that patient and the second is putting the cup
in that position. Keeping the pelvis in one position and
finding accurate pelvic/acetabular landmarks can be
challenging. The lateral opening angle is the easier part.
Most surgeons today agree that between 40 and 50 degrees is
desirable. Version is more complicated because the desired
acetabular version is dependent on femoral version.
Acceptable version is also related to the lateral opening
angle and the resultant bearing contact area. Again, the
issue is experience.
If I have any doubt about component positioning, I get an
intra-operative x-ray. Admittedly, there can be some
challenges to getting a good intra-operative view. For
what it’s worth, we did an x-ray review of my first 500
resurfacings (minimum 1 year follow-up). I have never had a
femoral neck fracture and all sockets are below 50 degrees
lateral opening.
Best wishes.
Thomas P. Schmalzried, M.D.
Tuesday, February 23. 2010
Computer aided navigation is an interesting concept. However,
there is no evidence that it leads to better clinical outcomes and fewer
failures. On the other hand, there is ample evidence that surgeon experience has
a dramatic effect on outcomes and complications.
One way to conceptualize this is that the experienced
surgeon’s brain is a computer with much more sophisticated
"software" than a navigation computer. When a computer is
programmed, an algorithm must be created which has certain
inherent limitations. Furthermore additional significant
sources of errors are introduced by the registration of
anatomic points for the navigation computer in surgery.
My personal opinion is that navigation that is based on a
pre-operative CT scan data, which is being pioneered by
Justin Cobb, has tremendous promise in the future to improve
the results. At this point, we are still in the early
development phase. It will probably add several thousand
dollars to the cost of each operation.
In summary, I believe the right kind of navigation surgery
based on accurate 3D CT scans holds tremendous promise for
the future. It will still require an extensive amount of
preliminary development work before it is ready for routine
use.
I hope this helps with this very complex issue.
Best regards,
Thomas P. Gross, M.D.
Tuesday, February 23. 2010
Computerized navigation has been around for a long time, in
total hips, total knees, and now hip resurfacing. A lot of
surgeons, including me, have tried it out and not seen an
advantage in all but very exceptional cases. Yet other
surgeons use it on every case.
This is what I think about computerized navigation: It is a
tool which can narrow the "bell-curve" of component
position, but the curve still has some spread. That helps a
surgeon avoid "outliers", or badly misplaced components.
Navigation does not make component position the exact same
every time, but it helps avoid those outliers. (If it was
the exact same every time there would be no bell-curve at
all.)
So, if a surgeon has no outliers, in other words if he is
doing a good job of keeping his personal bell-curve narrow,
there is no advantage to using computer navigation.
Alternatively, if a surgeon thinks he might accidentally
misalign a component so much that it would be considered an
outlier, the computer may prevent that.
Like any computer, what comes out depends on what went in.
Registering the anatomy (which tells the computer where
everything is) at the beginning of a computer-navigated
operation is not at all an exact science, but depends upon
knowledge and experience. It's the same with mechanical
alignment jigs. With either method, one should hope that the
surgeon is ready to adjust the verdict of the computer or
the jig to place the component accurately in the bones which
are clearly visible.
Are there any downsides to using a computer? Well, there is
the extra time involved, which prolongs the surgery (think
infections, blood clots). There is extra expense. There is
often one more person in the OR, and more traffic in the OR
can lead to infection. There is the possibility of surgical
complacency if the doctor believes in the infallibility of
computers.
I have heard this discussed at resurfacing meetings, and
people whom I respect more than any others in this field
have tried navigation and declared it "useless", and a
"waste of time". While unwilling to go quite that far, it
does make me think I am fine in continuing with mechanical
jigs.
Your question about doctors not having 100% "retention" due
to component malposition requires a reply. Personally, I
have not had any failures in almost 600 resurfacings due to
component malposition. I have 1 femoral neck fracture due to
leg presses 8 weeks after surgery, and one pelvis fracture
resulting from trauma 2 years after resurfacing. That's it.
But malposition is an important cause of fracture,
wear-related failure, and possibly pseudotumors as well, so
should be avoided.
Any surgeon "young" enough to learn hip resurfacing is
certainly young enough to learn the much easier task of
computer navigation, so people who consider someone too
"old" to learn navigation are being silly.
Similarly, a patient who would choose his surgeon based upon
their use of computer navigation is badly misguided. There
are many much more important issues to consider.
Having said all this, I wouldn't be surprised if at some
point in the future surgical navigation becomes more
accurate, easier, cheaper, and quicker. Robots will
substitute for doctors. Surgeons will look back on the old
days and shake their heads in amazement that we used to do
all this by hand.
Peter Brooks MD, FRCS(C)
Cleveland Clinic
Tuesday, February 23. 2010
Using computer navigation in joint surgery is a double
edged weapon. While potentially it can reduce the number of
outliers, it can also cause tremendous deviations and
absurd placements which would never be done with
conventional jigs. I have seen many examples of this done
elsewhere and referred to me for revision surgery.
Generally the input to the computer is made by a technique
known as bone morphing where the surgeon uses pointer probes
to point out the various bony landmarks to the computer. If
the surgeon makes an error in this step then it obviously
carries on in all further steps leading to a faulty
placement. To argue that it removes human error is most
irrational.
We have the brainlab navigation ( market leader in
navigation) in our unit since 2007 and I did a series of
cases at that time ( about 80 cases) . I have to say that
the femoral cap placement was inferior to my placement with
traditional jigs. However I found it useful when one had
distorted anatomy as in previous prox. femoral osteotomy. I
still use it for such cases.
There are many reasons in my opinion by which the
conventional jig is far superior to the navigation in hip
resurfacing.
1. bone morphing with the pointer probes damages the neck
capsule which I protect passionately during hip resurfacing
surgery and which I am sure is one of the key elements for
my success rate.
2. I use navigation routinely during my Total knee
replacements as the aim of the TKR surgery is to allign the
components to the hip and ankle which are not visible in the
surgical wound. In contrast in hip surgery the goal is not
to align hip component to the spine , pelvis or knee/ ankle.
The aim is to align components to local landmarks in the
surgical wound, the location of which is given to the
computer by the surgeon. Then the computer gives back the
same information which the surgeon offered in the first
place. ( this is unlike the TKR where the computer picks up
the hip on merely moving the hip and not morphing).
Arguments that the computer increases accuracy in hip
surgery is frankly absurd and have to be dismissed as
marketing techniques.
3. The concept of incorporating the combined anterversion
is now the key in operating on FAI ( Femoro- acetabular
impingement) which is the pathology in over 95 % of male
patients having primary osteoarthritis. This is a dynamic
assessment and can be done only with a jig using a lat
cortex pin and cannot be done with navigation.
Having said all of the above one must make a distinction
between what Prof. Cobb uses and what others use.
Prof . Cobb is the only one to my knowledge who uses a CT
based navigation. The CT gives information which the surgeon
cannot access unlike imageless navigation with all other
surgeons which depends on surgeon's input based on bone
morphing that defeats the whole purpose of navigation.
In conclusion I would like to say that imageless navigation
has very limited role in hip arthroplasty ( eg previosely
operated cases) and is an excellent tool in Knee
arthroplasty.
CT based navigation for hips which is still not available
commercially ( which prof. Cobb uses) may have a significant
role in hip arthroplasty. This has to be balanced with the
radiation dose for routine CT to be applied universally(
approx 30 -50 conventional x-ray dose )
wishing you the very best
with best regards
vijay bose
chennai
Friday, February 12. 2010
Smith & Nephew's strong profits beat expectations
February 2010
Smith & Nephew (S&N), the hips-and-knees
maker, posted higher profits in the final
quarter of last year after the replacement
joints market stabilized.
The market
suffered during the recession, but started
to recover in the second half.
Traditional hip and knee ranges, like its
Legion knee, did well, particularly in the
US, while products designed for younger,
more active patients, such as the
bone-sparing Birmingham Hip Resurfacing
System, were weak.
Younger patients were more likely to put
off surgery than retirees because they did
not want to take time off work or balked at
the cost.
"Our largest business, orthopaedics, saw
a good finish to a tough year," said chief
executive David Illingworth. "Market
conditions were a little less difficult than
in the first half."
He said it’s too early to say when
patients who deferred operations might have
them done, and S&N is struggling to push
through price increases as governments and
private clients have tightened their
budgets. But Illingworth was hopeful that
the $12bn global market for
replacement joints would improve, with
consumer confidence returning and
unemployment now falling.
S&N expects revenues in orthopaedics to
grow at the market rate this year after
lagging in 2009.
Profits before tax rose to $175m in the
fourth quarter from $162m a year earlier,
with revenues 11 per cent higher at $1.07bn,
helped by strong sales at the wound
management division.
Analysts and investors welcomed the
results, and the shares closed up 4.3 per
cent at 660p.
Sunday, February 7. 2010
Antibiotic Prophylaxis for Bacteremia in Patients with Joint Replacements by AAOS
February 2009 American Academy of Orthopaedic Surgeons
READ COMPLETE ARTICLE BY CLICKING HERE
This statement provides recommendations to supplement practitioners in their
clinical judgment regarding antibiotic prophylaxis for patients with a joint
prosthesis. It is not intended as the standard of care nor as a substitute for
clinical judgment as it is impossible to make recommendations for all
conceivable clinical situations in which bacteremias may occur. The treating
clinician is ultimately responsible for making treatment recommendations for
his/her patients based on the clinician’s professional judgment.
Any perceived potential benefit of antibiotic prophylaxis must be weighed
against the known risks of antibiotic toxicity, allergy, and development,
selection and transmission of microbial resistance. Practitioners must exercise
their own clinical judgment in determining whether or not antibiotic prophylaxis
is appropriate.
More than 1,000,000 total joint arthroplasties are performed annually in the
United States, of which approximately 7 percent are revision procedures.1 Deep
infections of total joint replacements usually result in failure of the initial
operation and the need for extensive revision, treatment and cost. Due to the
use of perioperative antibiotic prophylaxis and other technical advances, deep
infection occurring in the immediate postoperative period resulting from
intraoperative contamination has been markedly reduced in the past 20 years...
...Patients with joint replacements who are having invasive procedures or who
have other infections are at increased risk of hematogenous seeding of their
prosthesis. Antibiotic prophylaxis may be considered, for those patients who
have had previous prosthetic joint infections, and for those with other
conditions that may predispose the patient to infection. There is evidence that
some immunocompromised patients with total joint replacements may be at higher
risk for hematogenous infections. However, patients with pins, plates and
screws, or other orthopaedic hardware that is not within a synovial joint are
not at increased risk for hematogenous seeding by microorganisms...
...Given the potential adverse outcomes and cost of treating an infected
joint replacement, the AAOS recommends that clinicians consider antibiotic
prophylaxis for all total joint replacement patients prior to any invasive
procedure that may cause bacteremia.
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