Which Hip Device Do You Prefer?
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I was not keen to do the ASR when it was introduced. After a couple of years
when surgeon friends told me that it was good and I saw the results, I tried it
out in a phased manner.
Currently I use the BHR and ASR to almost about 50% each.
I make the decision based on technical preference in the particular patient. I
think the BHR and ASR are best suited for opposite ends of the spectrum of
patient and bone size.
One important advantage of the ASR is the small stem (peg) it has for the
smaller sizes. This is the huge advantage in small built individuals as the
proportion of the stem ( peg)to the residual bone is less. In contrast the BHR
has a same size peg through all sizes. A large peg in a small head size has the
potential problem of causing stress shielding . I almost never use the very
small size BHR like the 38 anymore.
In very big built patients who are bound to return to sports etc very soon the
BHR is the preferred option as the cup has a more high profile surface for bone
contact with a plastic disc for heavy impaction. The ASR is more fine and seats
without much impaction. This may be an advantage in relatively soft bone.
The other important way to harvest the advantage of prosthesis design is the
selecting the prosthesis based on the amount of head bone involved. The ASR
certainly removes less bone in the head than the BHR. This could be used to the
advantage of the patient in a condition like ankylosing spondylitis where the
problem is only in the articular cartilage with the bone being intact. Here the
ASR scores over the BHR.
However in a pathology like AVN there is significant head involvement, the BHR
has a distinct superiority as one would like to remove the diseased bone and
replace it with the metal.
Osteoarthritis lies somewhere inbetween where some patients have significant
head involvement where the BHR would be superior and in some others the head
bone may be largely intact and the ASR would be a better option.
Thus I choose the prosthesis based on technical issues and employ it to the
patient’s advantage. Thus in my practice both the ASR and BHR complement each
other. After doing more than 200 ASR over the last 2-3 yrs , I am as impressed
with the ASR as with the BHR.
I was one of the first to try out computer aided surgery for resurfacing. This
has no advantage except in patient who have had previous surgery like a
osteotomy . It has a very important disadvantage of removing all the capsule and
soft tissues on the neck of the femur ( to take a computer reading known as bone
morphing). This will compromise blood supply. I have to say that currently for
resurfacing computer aided navigation is only a marketing tool for surgeons/
companies. Computer aided navigation is very beneficial in knee replacements
where one has to align the knee components to the hip and ankle and I use it
routinely for knee replacements.
Wishing you the very best
With best regards
Center for Hip Resurfacing (ARCH)
I offer both prosthesis, the BHR and ASR to my patients, as I
am trained to do both.
The changes on the ASR are such that they have taken the good
of the BHR (so in the long term the result should be the same as
BHR), and eliminated some weaknesses of the BHR (so that in the
term the results might be better!). So all in all, it appears
the ASR should do better. When the BHR started, people did have
concerns about it at that time, and that would happen to
new. The ASR is not brand new! It has been around in clinical
practice for 1.5 years now, and as part of research trial prior
If you look at it a little differently - would you choose say an
average resurfacing surgeon (but who does the BHR) or a
surgeon (but who does the ASR?), if at all you were in such a
Taking into account the patient perspective and the doctor
perspective, I think its important to select a good resurf
first. If that surgeon offers both prosthesis, you can choose.
if he does not, then stick to the good surgeon and go by
prosthesis he uses.
I know there is no fixed correct answer here (and you know that
too!!!). These are just perspectives.
I definitely prefer the Birmingham
prosthesis compared to the others on the market. This relates to
the metallurgy with the as cast large block carbides and better
wear than the heat treated metals, the precise instrumentation
and the line to line fit of the femoral component, and the truly
impressive results at 10 year follow-up.
For the US surgeon, I prefer the Cormet device because I believe
the Cormet approach does a better job of helping the American
surgeon provide the American patient with a durable and
predictable long-term successful result. As I have mentioned
above, the long-term success of such an operation depends on
using a well thought out, well designed and manufactured device,
making certain that it is implanted properly, and being certain
that is placed in the appropriate patient. We have been very
fortunate in the US to have many different technologies and well
designed/manufactured devices available for addressing end-stage
hip disease. We have technologies that are now showing successes
out to 25 years. This has not been true for our colleagues
around the world. Corin submitted the Cormet device to the US
for clinical trial in 2001, and committed itself and its
investigators to learning about the operation and the devices.
This is a very important step in the process of new technology
introduction, as surgeons and companies find it easy to promote
operations and devices, but don’t always provide the necessary
steps to insure that the introduction of that technology to a
broader population can be done safely. The BHR has enjoyed
widespread success worldwide because of the significant
educational efforts of Mr. McMinn and his colleagues. They have
responsibly introduced the resurfacing operation, and educated
surgeons and patients on its performance. I am concerned that
that has not been the case in the US, where FDA approval was
granted based upon Mr. McMinn’s significant success, but few
American surgeons had come into contact with the device and
instruments. Corin, however, has performed a clinical trial with
the Cormet device, and with its partnership with Stryker, has
committed to the most thorough, consistent, and vigorous
training and education program in the US. As is Mr. McMinn with
the BHR device, I am biased about the product and support behind
the Cormet device (I am a consultant surgeon for Stryker and a
part of their teaching program) because I believe that it will
allow American patients to receive an excellent device,
implanted properly in the appropriate patient, and with the best
chance for long-term success.