Is Cemented or Cementless Hip Resurfacing the Best?
Dr. Rogerson
Hip Resurfacing: To Cement or Not to Cement –
that is the Question! By: John S. Rogerson, MD April 2015
We have received a number of inquiries in our office
regarding the merits of cemented versus non-cemented femoral
head components in hip resurfacing arthroplasty.Bear in mind that my experience with hip resurfacing to date has essentially been associated with the Smith and Nephew Birmingham
hip resurfacing system as designed by Drs. McMinn and Treacy.The system utilizes a line to line fit on the femoral head component with a very thin thickness of cement. A small amount
of liquid cement is poured into the hollow inverted femoral head
component and then extruded (and cleaned off as necessary) as it
is gently impacted onto the milled head/neck.This contrasts with the technique for a non-cemented femoral
component where the femoral head is reamed to a raw cancellous
surface which then abuts the porous coated inner surface of the
femoral head component and grows into the porous coating,
similar to what occurs on the acetabular socket component.
Why do I prefer the cemented technique as developed by Dr. McMinn?
1) The BHR has the longest experience and most successful
results globally of any of the presently used hip resurfacings
and utilizes the cemented technique.
2) None of the currently available porous coated femoral
component prostheses are FDA approved.
3) Many of the most severely involved arthritic hips have very
oblong and sclerotic (rock hard) bone on the top of the femoral
head that even when reamed has poor ingrowth potential and may
be more susceptible to stress shielding and/or loosening. In
order to compensate for this sclerosis and lack of sphericity,
there is a tendency to ream the head to a greater depth,
resulting in shortening and/ or injury to femoral circulation
and possible avascular necrosis. Cement utilization decreases
the above risks.
4) A thin cement mantle can compensate for asymmetric sclerotic
heads and allows one to place fixation holes or use small cysts
in the femoral head for the cement to lock into.
5) The most common femoral porous coated system on the market
has a round on round bone/metal interface which is less
resistant to rotational forces biomechanically.
6) Porous coating on the available non-cemented systems is
applied to the femoral component with heat treatment which
affects the metal carbide size and ultimate wear
characteristics.
7) Porous coating on the femoral side appears to be “fixing” a
problem that doesn’t exist-we have not experienced femoral
component loosening in our series or those previously referred
to Europe.
8) If loosening did occur, there would be no difference in ease
of revision between cemented vs. non-cemented prostheses.
In summary, there are numerous factors, as noted above, that
convince me that the BHR (with a cemented femoral head component
and a non-cemented porous ingrowth “as cast” acetabular
component) is the most successful hip resurfacing option with
the longest track record on the market today.
Dr. De Smet
“What is your opinion about cementless devices for resurfacing?”Maybe they are good, but we do not know yet. Cement is a shock
absorber between prosthesis and bone or between prosthesis/
bone+cement/ bone, so maybe a good thing, certainly taking in
account that Chrome Cobalt has not the same elasticity as bone
and is quite stiff!So
Greetz KOEN
At the beginning of my experience, all my resurfacings were cementless.
The results were not good for cementless femoral
components, but cementless acetabular cups were
excellent. Of course I have occasional patients
with a great result following a cementless
femoral component 16+ years post-op. For the
total group of patients, however, cementless
femoral components were not successful.In 1994 I started with hybrid fixation using a
cemented femoral component and a cementless cup. In my BHR
series, i.e. commencing 1997, I continued with hybrid fixation
and I have had no loose cups and no loose femoral components. It
would be hard to do better than have a zero loosening rate in
this large series of BHRs in patients with varying bone quality.
Thankfully patients who need resurfacing today need not be the
Guinea pigs for a new experiment. Hard information does exist on
this subject and should be used by surgeons and patients alike.
Those are the short answers to your questions, the long answers
are in a multi author book called Modern Hip Resurfacing which I
have edited and which will be published by Springer early next
year. When it is published, I will send you a signed copy.Best RegardsDerek
Dr. Gross
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Uncemented resurfacing components are a new development. The
acetabular components used routinely are uncemented, while the
femoral components routinely have been cemented to bone.There is virtually no published data on the use of an uncemented femoral component. I will need to gather data for at least three
to four years before I will be able to provide any useful data
on this subject. Fixation of total joint implants to bone can be
accomplished by cement or by porous ingrowth technology. Cement
fixation is immediate, while permanent fixation with uncemented
components requires a six to twelve months of bone ingrowth
before it is considered well fixed. Some total joint replacement
components have had more success with cement fixation, while
others have done better with uncemented technology.In hip surface replacement at eight years, approximately 95% of implants are still working in young patients with cemented
femoral fixation. Only rarely can these 5% failures be blamed on
the cement fixation itself.However, theoretically, cement is the weak link when long-term
(> 10 years) fixation of the femoral component is contemplated.
If uncemented femoral components can be shown to achieve
reliably high rates of ingrowth in the short term, they will
probably outperform cemented femoral components in the
long-term. It is also possible that avoiding cement may decrease
some of the early failure such as fractures or AVN of the
femoral head. This is because cement heats up during its curing
process and may traumatize the femoral head at the time of the
original surgery. This may be part of the cause of the fractures
or AVN seen in the few early failures of hip resurfacing.
At this point, I basically consider the cemented and
uncemented versions equivalent. I believe that the uncemented
femoral component will be superior but I do not know. Nobody
knows! Added risk of the unknown is taken by the patient who
wishes to try this new technology. If the uncemented femoral
component fails, revision to a cemented component will not be an
option; large bearing metal-on-metal total hip replacement will
be the second operation to revise the failed femoral resurfacing
component…
…There is virtually no published data on the use of an
uncemented femoral component. I will need to gather data for at
least three to four years before I will be able to provide any
useful data on this subject…
…In hip surface replacement at eight years, approximately 95%
of implants are still working in young patients with cemented
femoral fixation. Only rarely can these 5% failures be blamed on
the cement fixation itself…
…At this point, I basically consider the cemented and
uncemented versions equivalent. I believe that the uncemented
femoral component will be superior but I do not know. Nobody
knows! Added risk of the unknown is taken by the patient who
wishes to try this new technology. If the uncemented femoral
component fails, revision to a cemented component will not be an
option; large bearing metal-on-metal total hip replacement will
be the second operation to revise the failed femoral resurfacing
component.
I worked with Biomet on an uncemented femoral component and the
precision instrumentation required for this implant for the last
five years. The Biomet component has a full coating or Titanium
plasma spray under the entire under-surface of the femoral
component. This is the best implant available to maximize the
chance of bone ingrowth. To my knowledge, the only other femoral
component available in the world currently is from Corin. There
are some early experiments in Europe with this device. It is not
available in the US even on a study basis. When I originally
proposed an uncemented femoral component to Corin eight years
ago, they were unable to manufacture it. When I started working
with Biomet to develop an uncemented femoral component, Corin
also started to work on one. They were able to bring it to
market in Europe first; however, their component is only
partially porous-coated (less than 50%) with Titanium (but it
does have complete hydroxyl appetite coating. I personally do
not believe this is good enough for long-term fixation (>10
years), but nobody knows for sure yet. Finally, this year, we
have completed development of the uncemented Biomet femoral
component and quality control tested implants have begun rolling
off the assembly line in Warsaw, Indiana. In April 2007, I first
started implanting the uncemented femoral components. Biomet is
not yet able to produce enough for me to implant them in every
patient. Hopefully, soon, production will be increased so that
my needs can be met and other surgeons can also begin getting a
supply of these implants. Much interest has been generated for
these implants already.
My intention is to convert completely to uncemented femoral
components, as they become available. If a patient still prefers
the cemented version, I will be happy to use this in his/her
case.
At the time of this writing, I have implanted approximately 60
uncemented femoral components without immediate problems, (but
it is too early to say how they will work). I will not be
providing continuing public updates on the use of an uncemented
femoral component. Instead I plan to formally report my data
after three to four years of use, when I have meaningful results
to publish. I will be happy to take into account your personal
preference at the time of surgery. If you are absolutely
determined to have an uncemented device in the near future, I
will have to take this into account when we schedule a surgery
date for you, so that we can reserve an appropriate sized
implant. However, please understand that before three to four
years have rolled by, I will not be able to give you any better
information about the uncemented femoral component. I will not
be able to tell you if it is superior to the cemented component
or not until at least three to four years have passed. Even at
that time, it will be a very early judgment.
In summary:
Sincerely.
Thomas P. Gross, MD
08/23/2007
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