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Saturday, November 26. 2011
Approaches in hip resurfacing
The path that surgeons choose to arrive at the hip joint is called the
"approach". There are many different basic approaches used for hip resurfacing.
None has been proven to be superior to others based on valid scientific
research. Basically, I recommend that a surgeon use the method that he/she is
already most comfortable with when performing standard total hip replacement and
modify it as needed for the more complex hip resurfacing operation. My preferred
approach is the posterior. This is used in at least 70% of hip resurfacings done
worldwide. The next most common approach is the lateral (two versions:
anterior-lateral and direct-lateral). Finally the direct anterior and the Ganz
(or trochanteric, or internal dislocation) approach are far less commonly used.
All of these approaches are adapted slightly by different surgeons.
Continue reading "Dr. Gross discusses the Gantz vs other surgical approaches "
Sunday, November 6. 2011
I am not enthused about the Ganz trochanteric flip approach for several reasons. It was developed to be less injurious to the femoral blood supply. Koen DeSmet showed that with the modified posterior capsulotomy approach that he, Bose and I use that the blood supply compromise during is not much different than with a trochanteric osteotomy. Also, the incidence of AVN even with the much more extensive posterior capsular release that McMinn initially used is extremely low. We are now over 600 cases and have not seen a case of AVN.
Problems with any trochanteric osteotomy including the trochanteric flip all relate to injury to the gluteus medius attachment which results in an abductor lurch weak and awkward gait afterward. In this young and very active patient population, one is hard pressed to protect them for 6-8 weeks on crutches so the trochanteric bone can heal. If the patient is even relatively non-compliant, one is left with a lifelong limp that is impossible to fix. That is why the posterior approach became almost universal in America and the Charnley trochanteric osteotomy was abandoned. Paul Beaule recently reported on his series with trochanteric osteotomy and had a significant number of complications relative to the abductor mechanism.
In summary, this "flip" technique is a solution to a problem (AVN) that barely exists with the modified posterior capsulotomy approach and is associated with a significant number of "limps" and restrictions for a very active group of patients.
Dr. John Rogerson
Sunday, November 6. 2011
Comments by Dr. Vijay Bose
The ganz trochanteric flip is an excellent approach for doing open FAI surgery, for fixing fracture on the femoral head ( pipkin #) and for doing osteotomy of the femoral neck in post SUFE situations. In these non - arthritic situations a surgical dislocation of the hip is warranted without damaging the blood supply and I employ it routinely for these indications.
However its use in hip resurfacing is a bit of an overkill. It has been documented without a shadow of doubt that the post approach does not compromise the vascularity of the femoral head in an arthritic hip after resurfacing. Thousands of patients who have crossed the 10 yr mark with the post approach & BHR bear testimony to this.
Doing the ganz for resurfacing is a much more morbid procedure than a standard post approach. Any osteotomy will take more time to heal and recover function. The extended trochanteric osteotomy ( ETO) which is the bigger version of the Ganz flip will take about 6 months for the patient to regain function.
Intuitively the Ganz looks appealing as regards preserving blood supply but this issue is not relevant in an arthritic hip.
with best regards
vijay bose
chennai
Friday, November 4. 2011
Hi Pat,
You asked about the Ganz approach, which is also known as "surgical dislocation" of the hip for resurfacing.
This was described way back in 2001 by Prof. Reinhold Ganz in Berne, Switzerland. Resurfacing was being done in those days, although not so much by him, and he used it for all kinds of hip surgery from debridement to revision total hips. The key factor is that it is designed to preserve the blood supply to the femoral head. That is irrelevant in hip replacement because the femoral head is getting cut off anyway. In joint preservation procedures like FAI operations, labral repairs, removal of loose bodies etc and in hip resurfacing, it is important that the femoral head blood supply is respected.
Dr Ganz's major contributions have been his descriptions of the blood supply to the femoral head, and of femoroacetabular impingement (FAI) in the development of hip arthritis.
There is little question that the posterior approach routinely damages the blood supply to the femoral head. But there is also little question that this approach yields excellent outcomes in hip resurfacing, and is done by most US surgeons, about 80%. The pioneering surgeons McMinn and Treacy both use the posterior approach.
Continue reading "Dr. Brooks Compares theGanz Approach vs Other Surgical Approaches"
Sunday, March 28. 2010
A Modified Posterior Approach Preserves Femoral Head Oxgenation During Hip
Resurfacing 2010
Steffen RT, De Smet KA, Murray DW, Gill HS 2010 Mar 22
Original Link
http://www.ncbi.nlm.nih.gov/pubmed/20334994?dopt=AbstractPlus
Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences,
University of Oxford, Nuffield Orthopaedic Centre, Oxford, UK.
In 11 patients, the oxygenation was measured in the superolateral quadrant of
the femoral head during resurfacing with a modified posterior approach, designed
to preserve the blood supply, using a gas-sensitive electrode. These were
compared with measures from 10 patients in whom the standard posterior approach
was used. The modified approach patients maintained a significantly (P < .005)
higher amount of relative oxygenation after the approach, 78% (standard
deviation [SD], 45%) vs 38% (SD, 26%), and acetabular component implantation,
74% (SD, 56%) vs 20% (SD, 28%). The modified posterior approach, unlike the
standard extended approach, does not significantly compromise the blood supply
to the head; and we recommend this approach be considered for hip resurfacing.
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
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