I
have bone cysts, can I have a hip resurfacing?
The presence of a cysts by itself is not a contraindication
for resurfacing. It does not preclude resurfacing
automatically.
One must keep in mind that cyst formation is a natural
occurence in osteoarthritis and is very common though the
extent ,quantity & location may vary. Cysts are ofcourse
much more common and invariably present in AVN.
The assessment of certain technical factors would the real
issue. This is based on the amount of residual bone after
head preparation. Some resurfacing prosthesis are
thicker at the top and tend to replace more bone in the head
of the femur than other prosthesis. This is a great
advantage in managing cysts as at the end of head
preparation one is left with nearly 100% head support
in a majority of cases. The cysts get reamed away in bone
that would have been removed anyway. The BHR is a good
example of a prosthesis of this type.
The technical criteria which we we have been using in our
centre ( ARCH) for the last 7 yrs without any problems has
been termed as 'mid - path recommendations' because we chose
50% as an arbitrary value when we started.
1.The criteria are an intact - head neck junction across the
entire circumference to a height of 50% of profile cut ( the
actual height would vary depending on the size used)
2. Residual bone above the intack head neck junction must be
atleast 50%
Dr . Sugano from japan has done an experiment where he
removed 50% of head of fresh cadaveric bones and implanted a
cemented resurfacing on them . He also implanted a cemented
resurfacing on an equal amt of fresh cadaveric bones with
an intact head. He compared the mechanical strength of both
in the lab and found the mech. strength to be equal in both
groups.
The surgeon has to see the x-rays and CT scan before he can
comment on a particular case.
I have tackled successfully some hips with significant cyst
formation.
See
Webpage please see advanced OA with cysts and AVN.
The neck
capsule preserving approach
There are of course many views and
opinions amongst surgeons regarding the best approach and
what to preserve during the surgical approach. Failures in
resurfacing which occurs due to faulty approaches and
vascularity issue ,do so at the 3-6 yrs mark ( slow varus
collapse with loosening of femoral component ie AVN of the
entire head) . Hence, it is difficult to prove or disprove
any concept regarding this issue with statistical proof.
One needs a large number of cases followed up carefully for
a long time and have an opposite approach as a control
group. This would be very difficult in a clinical setting.
Therefore the best option would be to adopt a common sense path based on some
consensus that has already emerged in the resurfacing fraternity.
It is now more or less accepted that the anterior , anterolat or post approach
really has no influence as regards blood supply to the femoral head. (However
other factors like muscle damage etc may differentiate the Clinical result from
these approaches.)
There
are two components of blood supply to the femoral head
intra osseus ( within bone ) and extra osseus ( from outside
bone). The relative importance of these two blood
supply is again a source of great controversy amongst
surgeons. There is agreement however that in primary
osteophytic OA , there is more of the intraosseus component
and in non -oA cases there is less of the intraosseus
component.
The intraosseus blood supply
can be preserved by using a vent during femoral preparation.
This prevents fat and cement debris blocking the small veins
in the head of femur and neck. Though some surgeons would
not subscribe to this theory no one will argue that venting
the femur causes any harm. Hence it an excellent idea in my
opinion and this was developed by Derek McMinn.
The
extraosseus blood supply is maintained by preserving the
retinacular vessels on the femoral neck. This has been
experimentally again proved by prof. sugano and there is a
consensus on this.The best insurance one has in preserving
the retinacular vessels would be to preserve the capsule. In
theory one can take the capsule off and preserve only
the synovium to retain the retinacular vessels. This may be
alright but more risky and technically difficult to acheive.
Again no one can argue that presering the capsule does any
harm. Hence I advocate this strongly.
Therefore
not venting the femur and not preserving the capsule could
potentially cause great harm with femoral component failure
at the 3-6 yrs mark. Surgeons who do not advocate this may
be influenced by their early success with resurfacing
but will have to wait 6 yrs before they can say with
conviction that these technical issues are not important.
The
added advantage of preserving the neck capsule is the
ability to repair capsule to capsule at the end of surgery
which accelerates the immediate rehab . It may restore
proprioception to an extent.
The NCP approach (Neck
Capsule Preserving approach )was developed at the ARCH
centre in Chennai, India and is being increasingly adopted
by surgeons the world over for hip resurfacing surgery.
Why is Hip Resurfacing better than Total Hip Replacement?
Does Hip Resurfacing Remove More Acetabular Bone than a
Total Hip Replacement?
One of my patients from
India who has had a resurfacing, briefed me on the current
discussion in the surfachippy forum regarding Dr. Klappers
opinion of losing acetabular bone in an attempt to preserve
femoral head bone in resurfacing. He wanted to know my
opinion and I thought it would be appropriate for me to post
my answer in this forum. Dr. Klapper's opinion is way off
the mark. The acetabular size is the most important factor
which determines the choice of femoral head size in
resurfacing and one never removes more acetabular bone in
hip resurfacings. In other words if I would be performing a
conventional hip replacement on a given patient instead of
resurfacing, I would be using precisely the same size
acetabular component in both the surgeries.
I would go as far as saying that if we are taking out more
acetabular bone in resurfacing than in conventional hip
replacement , then in my opinion there is no role for
resurfacing and it must be discontinued immediately.
Acetabular conservation is as important if not more than
femoral bone conservation and all resurfacing surgeons
recognize and acknowledge this fact. The ability to put
large heads in resurfacing stems from the fact that thin
shelled acetabular components are possible with the modern
metal on metal bearings. However when one uses polyethylene
it has to have a large thickness ,which in turn reduces the
femoral head diameter , (assuming the acetabular outer shell
diameter remains the same). The same argument holds true for
ceramic on ceramic bearing to a lesser extent and therefore
slightly large femoral head sizes than metal on poly is
possible. However an anatomical size is currently possible
only with metal on metal bearings.
I strongly object to the terminology of "large or jumbo head
metal on metal hip replacement" that some surgeons use to
describe the current versions of the total hip replacements
which employ the same metal on metal bearing used in
resurfacings. I point out in all my lectures that this
variety of total hip replacement is the anatomical head
replacement giving the same natural size ( of the femoral
head and the acetabulum) that the patient has in other
normal hip and the conventional THR are indeed small head
hip replacements. One must never lose this perspective. I
hope this helps to clear the sudden doubt that was cast on
the hip resurfacing principle recently.
Does Hip Resurfacing limit ROM more than a THR?
One must remember that
with a resurfacing or a THR - one is not aiming to give
supra normal movement. One is merely trying to restore
normal movement present before the onset of hip arthritis.
The head- neck offset is an important determinant of ROM.
This is restored by a properly done resurfacing even in
patients who have a poor head neck offset as in FAI ( femoro
- acetabular impingement. Hence full restoration of ROM is
consistently possible in a resurfacing.
A big ball THR has an abnormally high head neck offset due
to the thin neck. Thus in theory a big ball THR can produce
supra normal movement . However this is neither desirable or
feasible in clinical practise as the head neck offset is
only one of the factors influencing ROM. Other factors like
soft tissue tension come into play. If one goes on making
the neck thinner progressively and the head progressively
larger --- it is wrong to imagine that this will translate
progressively into continued increase in Range of Movement.
In a badly done resurfacing, impingement can occur and this
will lead to abnormal wear pattern and in extreme cases can
be seen on x-rays. A properly done Resurfacing will
definitely match any type of THR for the ROM.
It is moot point that a Big ball THR will be more forgiving
for surgical errors than a resurfacing in respect to ROM.
With best regards
Vijay bose
chennai
What is
the Age Limit for Hip Resurfacing?
The chronological age is not an absolute criteria. The
physiological age, bone marrow density and the anticipated
post surgery activity level of the patients are the deciding
factors for the suitability of resurfacing procedure. X-rays
must be reviewed by the surgeon to assess technical
suitability. The youngest patient to undergo this procedure
by Dr. Bose is 14 years old. The oldest male patient was 73
years old and the oldest female patient was 70 years old.
Which is better a
BHR or an ASR?
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
Vijay bose
chennai
Asian Regional
Center for Hip Resurfacing (ARCH)
Website
Could a Dislocation happen after hip resurfacing?
It is a commonly used statement that a BHR is as 'stable' as
a normal hip. However this is a highly qualified statement.
This statement is true only if the following criteria are
met:
1. Native angles, inclination , offsets and all
anatomical parameters have to be replicated.. If this is not
done fully and only accuracy of say 80% is obtained - then
the stability is likely to be approx in the region of 80%
only. Having said this ,even in this situation, the
stability is likely to be many times that of a conventional
THR. Therefore I would not call it a surgical error. As
surgeons, we get better and better at this replication as we
gain experience.
2. The capsule should be
repaired to capsule preferably as it restores
the joint 'proprioception'( or position sense).
This would kick in the event of a potential
dislocation as it would in a normal hip. If the
capsule is repaired to bone , it is many times
better than doing nothing but does not achieve
the proximity to the stability of a normal hip.
Again it is not a surgical error if capsule to
capsule repair is not done but one cannot expect
natural stability.
3. Other factors that can
potentially cause dislocation like impingement
must be carefully addressed . The most common
offender is the non -restoration of the head
neck offset
One must keep in mind that the BHR is the
Ferrari of hips and the conventional THR is an
old fiat.
Even if the Gear knob of a ferrari is not the
right size for the driver it shows up because it
is pushed to the limit and built for
performance. However even if the chassis is
broken in an old fiat , it would probably go
unnoticed by the owner as it is never 'pushed'
for performance. There are many patients after
THR s with trochanteric non-unions going on for
many years without even being aware of it!
I have a metal allergy, can I have a hip resurfacing?
"Allergy after artificial joints is an interesting issue.
One must keep in mind that the co-cr-mo alloy has been in
clinical use for 45 yrs and is present in 99% of all hip and
knee replacement surgery. Even if a component is titanium
the articulating part would be always co-cr-mo. Therefore
metal sensitivity is not exclusive to metal on metal joints.
It is a factor in every joint replacement surgery and
therefore has been used in millions of patients. Skin
allergy is quite different from deep tissue allergy which is
mediated by different mechanisms of immune response by the
body. Thus skin testing is of no value when trying to gauge
deep tissue hypersensitivity. There have been reports of
hundreds of patients who had skin sensitivity but went on to
have very successful resurfacing. Only one thing can be said
about deep tissue sensitivity at this point in time --- it
is very very rare.
What
Precautions Should I Take Before Surgery?
It is advisable to avoid smoking completely. Blood thinners
like aspirin and oral contraceptives should also be stopped
for a minimum period of a week prior to surgery. NSAIDs like
ibuprofen cause bone softening and must be avoided to the
maximum extent possible. Paracetmol (Tylenol) or Proxyvon (Darvocet)
can be taken as alternative medications for the pain. It is
advisable to stay in good shape prior to surgery by good
aerobic exercises. However, this is a balance and
unaccustomed exertion which causes severe pain should be
avoided as this will provoke inflammation.
What is the Typical Recovery Time after a Hip Resurfacing?
At home they walk with a pair of crutches usually for about
10-15 days and when completely comfortable discard the
crutch on the side of the operation first. Then when the
other crutch is also felt unnecessary, this is also
discarded. Walking, climbing stairs or cycling can be done
for long periods of time.
There is no post –op restrictions after a Hip
Resurfacing operation and the patient can use it as a ‘normal
hip’. However the soft tissues around the Hip Joint, which were
contracted at the time of the hip disease, will take time to
relax following the excellent movement that has been restored in
the hip. Hence if there is pain while attempting a certain
activity like sitting on the floor, it implies the patient is
not yet ready for that particular activity. One can give a gap
of about a week and then try it again. Like wise the activity
level improves in a stepwise manner till the soft tissues also
become normal. Patient is ready for sports (inclusive of contact
sport) at about 3 months post-op.
Does hip resurfacing have a serious biomechanical
disadvantage - namely a small head-neck ratio?
Thanks for the mail. I read Dr. Kurtz thoughts on hip
resurfacing in his website. His concerns are very valid but
I cannot agree with his conclusions.
In short , his concerns only underline the fact that bad
results of resurfacing are due to badly done resurfacings. The head neck ratio
is an important determinant of range of movement and prevention of impingement.
In a patient with normal anatomy, if one is careful to restore anatomy the
range will be like pre-0p range of movement before the onset of arthritis. This
is a simple concept.
However many patients especially young osteoarthritis will
have FAI ( Femoro - Acetabular impingement) as the source of their arthritis. It
is of paramount importance to recognize it and deal with it time of
surgery. Again patients with an mild unrecognized slip in their earlier years
will have OA in the later years. Here again it is crucial to recognize and deal
with it at the time of surgery
As the head component in a resurfacing is centered on the neck and not the head
, correct placement will restore the head neck offset to a large degree. During
the surgery the metal cap will look very eccentric on the head.
Surgeons with less experience in resurfacing will think this
is wrong and will just put a cap on the translocated head resulting in very low
head neck ratio which will lead to problems postop.
In some severe cases , even if done correctly there may not
be adequate head neck offset. This is very rare and in this instance one has two
choices. In a very young patient , I would trim the ant neck to re-create the
offset. In an older patient I would proceed to use a stemmed component with the
same acetabular cup. One cannot underestimate the importance of bone
conservation in a young patient.
In a patient whose head - neck offset is carefully restored
to 'normal ' during surgery and the acetabulum inserted in correct orientation ,
patient will have 'normal' movement postop. Only a contortionist will need more
than 'normal' movement. Although in theory a large head THR can have supra
normal movement, this never happens in clinical situations because apart from
the head neck ratio there are many other factors determining ROM like muscle
tension etc.
By stating 69 degrees as the functional ROM In resurfacing ,
is Dr. Kurtz suggesting that resurfacing patients will not be able to sit in a
chair as that would require 90 degrees?
The mathematical calculations is very different from actual
clinical results in the human body.
The most practical example of this is in India where most patients would sit on
the floor even if the surgeon advises them not to as it is a very important
social requirement.
We did a study in our unit and found that 20 % of
conventional THR were able to sit and 76% of resurfacing patients were able to
sit. This again reiterates the importance of surgical technique.
Purely by choosing a particular prosthesis one cannot
guarantee a near normal ROM- it has to be installed correctly. However the
resurfacing/ anatomical head is the best tool in the surgeon's hands to restore
near normal ROM.
Dr. Kurtz also has mentioned component height which would give a prominent head
neck junction if not seated. I fully agree with this and it would cause serious
problems if not seated. The bottom line is again technique related and one must
fully seat the component.
The next issue is impingement which he has raised. The concern in very valid
because resurfacing acetabular components typically subtend a larger angle at
the periphery than conventional THR cups.
Therefore it is more difficult to bury the anterior edge
beyond the bone margin in a resurfacing . I would do this in all cases and would
never accept ant edge of the cup to be more proud than the bony margin.
Therefore the issue of neck- prosthetic impingement does not arise in my
opinion. Again is a matter of surgical technique.
Some of his statements, are simply not true. - like the ones given below
One does not remove more acetabular bone in the acetabulam than in a THR. - if
someone is doing this he is doing something seriously wrong. I have explained
this concept earlier. If any resurfacing surgeon is doing this he must be
condemned.
The incision for resurfacing is not bigger than for THR . It has been published
by Derek McMinn that Hip resurfacing can be done by MIS and results are same.
See Website
My incisions for both resurfacing and THR is about 10 to 14
cms and the length variability depends on the constitution of the patient and
not on the procedure. If a surgeon is using larger incision for resurfacing than
for THR, it is not wrong but is in the learning curve of the procedure.
Arguments like that of the removal of labrum and cutting of the capsule in a
resurfacing will cause problems sounds to be weak attempts to pick holes in the
outstanding functional results that have so far been achieved in the last 12 yrs
in resurfacing. The capsule is not removed in a resurfacing but carefully
preserved and stitched back capsule to capsule ( the NCP approach or the neck
capsule preserving approach for resurfacing). It is certainly true that the
surgeon has to give much more importance to the preservation of neck capsule in
resurfacing than in a THR.
It appears to me surgeons confuse many aspects of resurfacing. The old poly
resurfacings results must not be mixed with the modern metal on metal
resurfacings.
There are two dif concept in a resurfacing which was
introduced to the orthopedic community at the same time and hence gets mixed up.
The first is the use of an anatomical sized bearing. This implies the head
diameter to be the same as that of the native head. It is important to
understand that the aim is not to put in the biggest sized head that is
possible. If a larger than a native size is uses, it will bring a dif. set of
problems. Anatomical sized bearing can be done with a resurfacing or with
anatomical metal on metal THR ( people refer to this wrongly as large head ---
it is actually the correct head and all other heads are indeed small heads).
Now , currently one can use the BMHR as well. I have attached the pics which
illustrates it. Hip Resurfacing is not the aim here - the goal is to
restore an anatomical bearing which would be best attempt at restoring near
normal function. One has to use the best devise to achieve this goal.
Restoring an anatomical bearing is the
goal in a high value hip.- high value hip means in
patient who have a lot of demand out of their hips. An
elderly sedentary patient can have any hip and any
articulation. It would make no difference. However an
wear resistant anatomical bearing is the goal in a
patient who has demand of the hip for occupational ,
recreational or social customs.
This is the first aim. The next issue is of bone
conservation . Importance of bone conservation is
determined by relative importance of 3 factors, namely
the age , the activity level and the bone stock. Bone
preservation is not a static concept. Bone conservation
would be of immeasurable value in a 25 yrs old and would
be probably be a contraindicated in 80 yrs old due to
the risk of femoral neck fracture. I have attached a pic
to illustrate this point.
Thus there are two dif issues here -
the use of an anatomical sized bearing & bone
conservation. These are independent issues . As both
these concepts came simultaneously with the advent of
resurfacing there has been a hotch-potch with many
confusing these two.
What surgical approach is best - posterior or anterior?
There are two ways to look at approaches to hip resurfacing
or any hip arthroplasty. One is to view it with the amount
of muscle damage done. The other is to view it in respect to
the blood supply or the vascularity. The post approach is
traditionally known as the muscle sparing approach and the
anterior and anterolateral approaches are the muscle
compromising approaches. These approaches are known as
Hardinge approach or London hospital approach. There are
many more modifications of this with slight variations but
essentially they are the same and they disturb muscles to
varying extents. The muscle here refers to the Abductor
group or the muscles which lift your leg sideways and is the
most important muscle of the hip. The post approach spares
this completely. Interestingly there is now an anterior
approach which is getting to be very popular for mini -THR
and this is known as the mini Watson Jones approach or the
micro hip approach. This does not disturb the abductor
though it a ant. approach. However resurfacing cannot be
done through this approach. Even when one does a THR the
head has to be sawed off in place and then delivered out
separately. Or in other words the hip cannot be 'dislocated'
through this approach which precludes hip resurfacing.
However some muscle have to be cut in any approach to get
access to the hip and in the post approach, one cuts the
short ext rotators which are flimsy , small muscles in the
back of the hip. These are stitched back. These muscles are
relatively unimportant. It is largely accepted that the post
approach is more conducive to early and complete return of
function as it is muscle sparing. The ant approaches which
disturb the gluteus medius will result in slower and
incomplete return of function depending on the amount of
muscle disturbed and the intactness of the muscle repair
over long term. The younger and the more active the patient
, the more would be the perceptible difference between the
ant and post. approaches as regards function. Thus an
elderly patient having a THR will appear to have the same
result with either approach whereas a young patient having a
resurfacing will have an obvious difference.
Michael Freeman , an English surgeon established
in 1978, the fact that the blood supply in an osteoarthritic
hip is different from a normal hip. In full blown arthritis
the blood supply to a large extent changes to inside bone(
intra-0sseus) from a pattern that is predominantly outside
bone (extra osseus ).Therefore in osteoarthritis , any
approach can be attempted without a risk to the blood
supply. Hence in osteoarthritis, as the blood supply issue
is taken out of the equation only the muscle damage is
relevant and therefore post approach is better. In fact when
Derek McMinn developed modern resurfacing , he first
attempted it through the anterior approach and found so much
of muscle damage that he decided to change to posterior.
However in non-OA indications like AVN , the
situation is little different and the intra-osseus blood
supply is not well developed. Increasingly it is becoming
increasingly obvious that neck capsule preservation is vital
in these non-OA indications. Hence we have developed the
neck capsule preserving ( NCP ) approach where the end
arteries to the neck and head -neck junction has to be
preserved. We have been doing the NCP approach for the last
6 yrs in predominantly non-oA indications with excellent
results.
Neck capsule preservation is not possible
through the anterior approach and therefore the post
approach is more suited for non-OA indications. The other
benefit of the NCP approach is the fact the capsule is also
repaired back completely so that the surgeon can confidently
advise patients that there wont be any restrictions post-op.
The repaired capsule will prevent the patient from doing any
awkward movement even inadvertently. This is very useful in
the first 6 weeks which is the time taken for a pseudo
capsule to form when the surgeon does not stitch back the
capsule . Therefore capsule repair is of relevance only in
the 1st 6 weeks
The 3rd issue comes into play when a femoral
component of a resurfacing is done uncemented. This is the
situation where one has to be extraordinarily careful as
even a little necrosis of the head bone would cause failure
of the implant. When one uses cement, the cement converts
the head into a 'composite' of live bone, dead bone and
cement. Some bone unviablility is easily tolerated due to
the presence of cement. Therefore in uncemented femoral
resurfacing one has to use the Ganz approach or surgical
dislocation where the blood> supply should preserved
entirely. Although this appears to be desirable in theory
for all resurfacing it has its own problems. It involves a
trochanteric osteotomy and reattachment with screws. The pt
has to be partial weight bearing for 6-8 weeks till the
ostetomy unites. Prof Ganz from Berne developed this
approach for non arthritic hips for pts in their 20s to
treat femoral acetabular impingement (FAI). These patients
have a completely normal pattern of blood supply (completely
exta-osseus) and in spite of this, pts do not develop any
problems. This technique is described as surgical
dislocation and surgeons employ this for any condition that
requires a dislocation of a normal ( non-arthritic) hips.
The surgical dislocation is always done posteriorly.
Thus 3 different situations with regard to
resurfacing need 3 different approaches and all of them are
posterior! Anterior or posterior refers to which side the
hip is dislocated and not on where the incision would be.
Irrespective of whether anterior or posterior approach is
done , the incision will always be on the side ( exactly
lateral). So one cannot deduce approach employed by looking
at the incision. Therefore the skin incision is same for
both approaches.
Explain
Dislocations
For those of us outside the US, Rob Barrack is the
name that we associate the most with the BHR. He has
spear headed the spread of resurfacing in the US and
is an excellent choice of surgeon and I would
recommend him highly. It is truly unfortunate that
this lady has sustained a dislocation of a BHR.
It is a commonly used statement that a BHR is as
'stable' as a normal hip.
However
this is a highly qualified statement.
This statement is true only if
the following criteria are met.
1. Native angles, inclination ,
offsets and all anatomical parameters have to be
replicated.. If this is not done fully and only
accuracy of say 80% is obtained - then the stability
is likely to be approx in the region of 80% only.
Having said this ,even in this situation, the
stability is likely to be many times that of a
conventional THR. Therefore I would not call it a
surgical error. As surgeons, we get better and
better at this replication as we gain experience.
2. The capsule should be repaired
to capsule preferably as it restores the joint 'proprioception'(
or position sense). This would kick in the event of
a potential dislocation as it would in a normal hip.
If the capsule is repaired to bone , it is many
times better than doing nothing but does not achieve
the proximity to the stability of a normal hip.
Again it is not a surgical error if capsule to
capsule repair is not done but one cannot expect
natural stability.
3. Other factors that can
potentially cause dislocation like impingement must
be carefully addressed . The most common offender is
the non -restoration of the head neck offset. One
must keep in mind that the BHR is the Ferrari of
hips and the conventional THR is an old fiat.
Even if the Gear knob of a
Ferrari is not the right size for the driver it
shows up because it is pushed to the limit and built
for performance. However even if the chassis is
broken in an old fiat , it would probably go
unnoticed by the owner as it is never 'pushed' for
performance. There are many patients after THR s
with trochanteric non-unions going on for many years
without even being aware of it!
Coming to the specifics of this
patient.- The Relocated BHR is likely to be stable
with time and is unlikely to affect longevity. The
only issue is that this patient must avoid extremes
of movement to prevent another episode.
Is
Incision Length important?
Yes, it is true that Minimally invasive approach has been
proven not to have great benefits over a conventional
incision in terms of blood loss, pain , or speed of recovery
in the same surgeons hands. It is only of cosmetic value.
All studies to investigate this have been done on two groups
of patients in which a single surgeon employs the two
approaches in the diff groups.
When a surgeon who is capable of doing a minimally invasive
approach does a conventional approach it is logical that the
conventional technique will be only marginally bigger and
therefore advantages do not show up in studies. However if a
minimally invasive approach of a surgeon is compared with a
conventional approach of another surgeon who never does
minimally invasive or never makes an attempt to reduce his
incision size (within comfort levels)- the differences will
show up.
When one compares an incision which is 5 cms for a
particular procedure with another which is 50 cms for the
same procedure - the differences will show up without any
doubt.
However to see objective difference between an incision
which is 5 cms and 8 cms it is difficult This is a question
of degree.MIS approach has been accused to be just a
marketing trick which has caused more harm than good. This
is true in many instances however one must be careful not to
confuse MIS surgery with the concept of minimizing incision
size.
When surgeons are focused on doing a surgery with a pre-
determined incision size like say 10 cms - they are hell
bent on doing this through this incision even though they
are struggling and probably getting many things wrong in the
deep bone work. This is certainly not good. Scientific
papers enumerating surgical disasters when this is employed
is common place.
The other side of the coin is when surgeons chop up patients
to extraordinary lengths. Certainly it is equally wrong to
cut up tissues unnecessarily when the same can be
accomplished to the same degree of accuracy by employing a
much smaller incision. In other words it is certainly the
duty of the surgeon to minimize the length of incision of
any elective procedure but ensuring that he is comfortable
and deep bony work is not compromised in any way. There
should not be any predetermined length but the surgeon must
consciously reduce incision size as a guiding principle.
Undoubtedly a hip incision that goes all the way to the knee
will have many other bad effects apart from the
scar.Therefore there is no doubt that surgeons must be
constantly striving to reduce incision size without
compromising any other factor. However trying to work with a
pre-determined incision size is frequently a recipe for
disaster. It is also well accepted that revolutionary
techniques like the two incision technique for THR in which
the surgeons previous experience with THR is rendered
completely useless is very risky when compared evolutionary
techniques in which surgeons reduce incision size
progressively.
Surgical speed is another interesting topic. The fastest
hand that i have seen wield the scalpel in undoubtedly Ronan
Treacy who can finish a resurfacing in 20-25 mts. However
Mr. McMInn who invented resurfacing and who of course
trained Mr. Treacy still takes close to two hours. The
turnover time will be 3 hrs.
I still take close to two hrs for a resurfacing with a
turnover time of 3 hrs. There are so many steps and no
matter how fast you do them it takes that amount of time to
do all the steps. The neck capsule preservation that i do
takes extra time as well. Attempting to reduce incision size
and using subcuticular absorbable stitches all add up the
time taken for surgery. If I don't do all these I probably
can finish in an hour. If I should finish a resurfacing
within half an hour there is no doubt I will be skipping
steps.
I have now done more than 500 resurfacings. I have had two
failures so far. One was due to deep infection and the other
was to head collapse which led to the development of the
neck capsule approach.
Explain the
Minimally
Invasive Approach to Surgery
Yes, it is true that minimally invasive approach has been proven not
to have great benefits over a conventional incision in terms of
blood loss, pain , or speed of recovery in the same surgeons hands.
It is only of cosmetic value.
All studies to investigate this have been done on two groups of
patients in which a single surgeon employs the two approaches in the
diff groups. When a surgeon who is capable of doing a minimally
invasive approach does a conventional approach it is logical that
the conventional technique will be only marginally bigger and
therefore advantages do not show up in studies. However, if a
minimally invasive approach of a surgeon is compared with a
conventional approach of another surgeon who never does minimally
invasive or never makes an attempt to reduce his incision size
(within comfort levels)- the differences will show up.
When one compares an incision which is 5 cms for a particular
procedure with another which is 50 cms for the same procedure - the
differences will show up without any doubt. However to see objective
difference between an incision which is 5 cms and 8 cms it is
difficult This is a question of degree.
MIS approach has been accused to be just a marketing trick which has
caused more harm than good. This is true in many instances however
one must be careful not to confuse MIS surgery with the concept of
minimizing incision size When surgeons are focused on doing a
surgery with a pre- determined incision size like say 10 cms - they
are hell bent on doing this through this incision even though they
are struggling and probably getting many things wrong in the deep
bone work. This is certainly not good. Scientific papers enumerating
surgical disasters when this is employed is common place
The other side of the coin is when surgeons chop up patients to
extraordinary lengths. Certainly it is equally wrong to cut up
tissues unnecessarily when the same can be accomplished to the same
degree of accuracy by employing a much smaller incision. In other
words it is certainly the duty of the surgeon to minimize the length
of incision of any elective procedure but ensuring that he is
comfortable and deep bony work is not compromised in any way. There
should not be any predetermined length but the surgeon must
consciously reduce incision size as a guiding principle. Undoubtedly
a hip incision that goes all the way to the knee will have many
other bad effects apart from the scar.
Therefore there is no doubt that surgeons must be constantly
striving to reduce incision size without compromising any other
factor. However trying to work with a pre-determined incision size
is frequently a recipe for disaster. It is also well accepted that
revolutionary techniques like the two incision technique for THR in
which the surgeons previous experience with THR is rendered
completely useless is very risky when compared evolutionary
techniques in which surgeons reduce incision size progressively.
Surgical speed is another interesting topic. The fastest hand that I
have seen wield the scalpel is undoubtedly Ronan Treacy who can
finish a resurfacing in 20-25 minutes. However Mr. McMinn who
invented resurfacing and who of course trained Mr. Treacy still
takes close to two hours. The turnover time will be 3 hrs. I still
take close to two hrs for a resurfacing with a turnover time of 3
hrs. There are so many steps and no matter how fast you do them it
takes that amount of time to do all the steps. The neck capsule
preservation that I do takes extra time as well. Attempting to
reduce incision size and using subcuticular absorbable stitches all
add up the time taken for surgery. If I don't do all these i
probably can finish in an hour. If I should finish a resurfacing
within half an hour there is no doubt I will be skipping steps.
Explain
Loose or Slipped
Acetabulum Cups
The issue of cup slippage in the immediate postop
period is a controversial one.
While bone ingrowth takes around 6 wks. - the hydroxy
apatite to bone chemical reaction can occur much more
quickly.
If we surgeons feel that the cup
is not perfectly tight ( press fit) during the surgery then
we restrict activities for a 6 -8 wk period .This is done in
the hope that no precipitating event would occur that would
tilt the balance adversely till some stability occurs as we
have not achieved primarily stability during surgery. I must
say that most of these times we are able to 'escape'
component loosening.
I have done this a few times in my very early cases
, many years ago. Of course these days we get such
spectacular fixation of the cup primarily that many of my
patients are visiting the gym in 5-6 days following surgery.
Achieving primary stability in the resurfacing
surgery is more difficult as by definition there are no
screws in the acetabular cup of a resurfacing as the entire
cup is an articulating part ( monobloc ) cup. This is
different from a cup in a THR where the surgeon can easily
get additional stability by putting some screws if an
adequate press fit is not achieved. Since a liner is always
used in a THR cup , this is feasible.
Thus
the early cup loosenings are certainly going to be more in
resurfacings esp. when the surgeon is in the learning curve.
An extension of this concept implies, that surgeons who use
screws routinely for the cups in the THR may find the
resurfacing cup without screws more difficult to install.
Another issue is that if the cup is installed very
loose , a fibrous fixation occurs - very similar to
non-union in a fracture situation. If this occurs this will
prevent bony incorparation of the cup permanently. This cup
is at risk for many years following surgery. One of the
things that we look for in the postop films is the bony
incorporation ( osteointergration) of the cup.
Explain of the Posterior vs. Anterior Approach to Surgery
The post approach which I employ is
traditionally known as the muscle sparing approach and the
anterior and anterolateral approaches which is very popular
in the U.S and some parts of Europe are the muscle
compromising approaches.
The muscle here refers to the Abductor group or the muscles
which lift your leg sideways and is the most important
muscle of the hip. The post approach spares this completely.
However some muscle have to be cut in any approach to get
access to the hip and in the post approach, one cuts the
short ext rotators which are flimsy , small muscles in the
back of the hip. These are stitched back. These muscles are
relatively unimportant as the main ext rotator is the
gluteus maximus which again is undisturbed.
Increasingly surgeons the world over are realizing the
importance of preserving capsule over the neck of the femur
in resurfacing surgery especially in cases where there is
little or no arthritis as in AVN and the blood supply comes
from outside bone( extra-osseus) , in contrast to full blown
arthritis where the blood supply to a large extent changes
to inside bone( intra-0sseus) .
This NCP approach ( Neck Capsule Preserving ) for
resurfacing surgery was developed here in Chennai. The other
benefit of the NCP approach is the fact the capsule is also
repaired back completely so that the surgeon can
confidentently advise patients that there wont be any
restrictions post-op. The repaired capsule will prevent the
patient from doing any awkward movement even inadvertently.
Summary of Advantages - Posterior vs. Anterior Approach:
The posterior approach for hip resurfacing has the following
advantages now that the instrumentation has been redesigned
specifically for that approach:
1. No important muscle groups are sectioned.
2. There is no release of the abductor muscles. They are the
most important muscles stabilizing the hip during walking
and other activities.
3. The gluteus medius and minimus remain intact. The only
muscle groups that are released are the short rotators that
are repaired at the conclusion of the procedure. However, no
important gait or other disturbances results from a release
even if they are not repaired because the rotation is
accomplished by other muscles. One of the two insertions of
the gluteus maximus tendon which extends the hip may be
released and if so then repaired. The other insertion
remains intact and there has been no significant
physiological damage to date.
4. The new instrumentation facilitates a smaller incision
especially in thin individuals. A longer incision is
necessary in well muscled or overweight patients. A slightly
longer incision is necessary in resurfacing than when the
head and neck are amputated in conventional THR. In hip
resurfacing the surgeon must work around the head and neck
to be able to prepare the acetabulum and implant the socket
accurately. Hip resurfacing is technically more demanding
and takes slightly longer. Since hip resurfacing is an
anatomical replacement, leg length equalization is
facilitated and more precise. Leg length equalization in THR
is more demanding, less certain and requires an
intra-operative X-ray.
5. The anterior approach requires removal of some of the
abductor muscles for either hip resurfacing or THR. Even
though they are repaired this reattachment may not be 100%
successful.
Explain the
Anterior and Posterior Approaches to Surgery
Thursday August 10, 2006
There are two ways to look at approaches to hip resurfacing
or any hip arthroplasty. One is to view it with the amount
of muscle damage done. The other is to view it in respect to
the blood supply or the vascularity. The post approach is
traditionally known as the muscle sparing approach and the
anterior and anterolateral approaches are the muscle
compromising approaches. These approaches are known as
Hardinge approach or London hospital approach. There are
many more modifications of this with slight variations but
essentially they are the same and they disturb muscles to
varying extents. The muscle here refers to the Abductor
group or the muscles which lift your leg sideways and is the
most important muscle of the hip. The post approach spares
this completely. Interestingly there is now an anterior
approach which is getting to be very popular for mini -THR
and this is known as the mini Watson Jones approach or the
micro hip approach. This does not disturb the abductor
though it a ant. approach. However resurfacing cannot be
done through this approach. Even when one does a THR the
head has to be sawed off in place and then delivered out
separately. Or in other words the hip cannot be 'dislocated'
through this approach which precludes hip resurfacing.
However some muscle have to be cut in any approach to get
access to the hip and in the post approach, one cuts the
short ext rotators which are flimsy , small muscles in the
back of the hip. These are stitched back. These muscles are
relatively unimportant. It is largely accepted that the post
approach is more conducive to early and complete return of
function as it is muscle sparing. The ant approaches which
disturb the gluteus medius will result in slower and
incomplete return of function depending on the amount of
muscle disturbed and the intactness of the muscle repair
over long term. The younger and the more active the patient
, the more would be the perceptible difference between the
ant and post. approaches as regards function. Thus an
elderly patient having a THR will appear to have the same
result with either approach whereas a young patient having a
resurfacing will have an obvious difference.
Michael Freeman , an English surgeon established in 1978,
the fact that the blood supply in an osteoarthritic hip is
different from a normal hip. In full blown arthritis the
blood supply to a large extent changes to inside bone(
intra-0sseus) from a pattern that is predominantly outside
bone (extra osseus ).Therefore in osteoarthritis , any
approach can be attempted without a risk to the blood
supply. Hence in osteoarthritis, as the blood supply issue
is taken out of the equation only the muscle damage is
relevant and therefore post approach is better. In fact when
Derek McMinn developed modern resurfacing , he first
attempted it through the anterior approach and found so much
of muscle damage that he decided to change to posterior.
However in non-OA indications like AVN , the situation is
little different and the intra-osseus blood supply is not
well developed. Increasingly it is becoming increasingly
obvious that neck capsule preservation is vital in these
non-OA indications. Hence we have developed the neck capsule
preserving ( NCP ) approach where the end arteries to the
neck and head -neck junction has to be preserved. We have
been doing the NCP approach for the last 6 yrs in
predominantly non-oA indications with excellent results.
Neck capsule preservation is not possible through the
anterior approach and therefore the post approach is more
suited for non-OA indications. The other benefit of the NCP
approach is the fact the capsule is also repaired back
completely so that the surgeon can confidently advise
patients that there wont be any restrictions post-op. The
repaired capsule will prevent the patient from doing any
awkward movement even inadvertently. This is very useful in
the first 6 weeks which is the time taken for a pseudo
capsule to form when the surgeon does not stitch back the
capsule . Therefore capsule repair is of relevance only in
the 1st 6 weeks
The 3rd issue comes into play when a femoral component of a
resurfacing is done uncemented. This is the situation where
one has to be extraordinarily careful as even a little
necrosis of the head bone would cause failure of the
implant. When one uses cement, the cement converts the head
into a 'composite' of live bone, dead bone and cement. Some
bone unviablility is easily tolerated due to the presence of
cement. Therefore in uncemented femoral resurfacing one has
to use the Ganz approach or surgical dislocation where the
blood> supply should preserved entirely. Although this
appears to be desirable in theory for all resurfacing it has
its own problems. It involves a trochanteric osteotomy and
reattachment with screws. The pt has to be partial weight
bearing for 6-8 weeks till the ostetomy unites. Prof Ganz
from Berne developed this approach for non arthritic hips
for pts in their 20s to treat femoral acetabular impingement
(FAI). These patients have a completely normal pattern of
blood supply (completely exta-osseus) and in spite of this,
pts do not develop any problems. This technique is described
as surgical dislocation and surgeons employ this for any
condition that requires a dislocation of a normal (
non-arthritic) hips. The surgical dislocation is always done
posteriorly.
Thus 3 different situations with regard to resurfacing need
3 different approaches and all of them are posterior!
Anterior or posterior refers to which side the hip is
dislocated and not on where the incision would be.
Irrespective of whether anterior or posterior approach is
done , the incision will always be on the side ( exactly
lateral). So one cannot deduce approach employed by looking
at the incision. Therefore the skin incision is same for
both approaches.
Explain the
Difference Between the BHR vs ASR Hip Prostheses
We, orthopedic surgeons find it difficult to weed out commercial
promotional jargon from scientific data. I sure appreciate how difficult it
would be for patients! Regarding the comparison of devices, the BHR was the
original device and the others are copies of it. The BHR presently has a 9 year
clinical history.
The 35 yr history of some metal on metal hip replacements (Ring & Mckee
Faraar) was the major catalyst that led to the development of the BHR and
the Birmingham designers took great care to duplicate the metal and clearances
of the historical devices so that they can draw on the 35yr history. All other
devices are deviances from the historical metal on metal THR devices and thus
cannot draw on that history.
All other devices have a very short clinical history. Every manufacturer
naturally will claim that their devise is the best and will quote varied reasons
substantiating their claim. However , in any kind of joint replacement surgery ,
the track record is the most important feature and must be given exceptional
importance. It is quite opposite of choosing a car, where the latest model is
probably the best. The performance of a prosthesis when implanted may be quite
different from lab tests. One can always exchange the car if it does not perform
well but unfortunately in joint replacement things are not so simple!
The ASR (as all other prosthesis ) have claims of superiority on lab testing.
This is completely different scenario from how the implant behaves after
implantation in a patient. Only time will tell as to which of these will work
and which will fail.
Depuy (manufacturer) claims that the ASR is better because it is thinner than
the BHR. Another manufacturer claims exactly the opposite i.e. that their
product is thicker than the BHR and hence superior. Their opinion is that the
thicker component serves the resurfacing cause better. The same goes for stem.
Some of the new designs have smaller design claiming less stress shielding and
some other have longer and thicker stems claiming to splint the neck of femur
avoiding a fracture risk.
Thus you will find people changing some characteristics of the gold standard BHR
and claim superiority. Some of these changes may indeed be good. However
only time will tell whether they are desirable changes or fatal mistakes.
The history of orthopaedic surgery is littered with similar cases. One of the
most important and well known is the Exeter THR stem which currently has
the best results of a cemented hip replacement and can be considered to be the
Gold standard. The manufacturer/developer surgeons decided to alter the surface
treatment into a matt finish from a polished one. This resulted in a very
high failure rate but it took 6-7 yrs for someone to work out the association.
The Exeter stem then went back to its original polished stem. Who could a
guessed that a surface finish of a non articulating part of a prosthesis would
cause such a drastic change in results?
The responsibility of the surgeon is not confined to the surgery alone. Post op
performance of the implant is also a surgeon's responsibility . This makes me
cautious.
I am not a gambling man, hence I stick with the BHR. However, when the choice is
not made by me , I do use other devices. Patients have requested specific
devices and i have used them. In other instances surgeons have asked me to use
other implants when I have gone over to other centres to help them do
resurfacing surgery and I have complied. I have nothing against other implants
but no one can deny that they are a bit of a gamble.
Explain
AVN and Hip Resurfacing
Tony has informed me about the AVN discussion currently on
surfacehippy. I have given the explanation of how a
resurfacing works in AVN. I must apologise that it is long-
winded and a little technical . However with the best of my
efforts i could not make it any easier as it a complex
concept to explain.
I have now done about 185 resurfacings for AVN cases over a
5 year period with many patients crossing the 4 yrs mark. It
is interesting to note there has not been a collapse or
fracture neck of femur even in a single patient.
It is wrong to think that the AVN continues forever in the
femoral head. AVN is a one time event in which a strikingly
similar sector of necrosis occurs in most femoral heads (
anteo supero lateral
part.) due to blockage of presumably the same vessel in all
patients. This sets off a series of changes which are is
marked by sectoral collapse. This is primary collapse of AVN
and most patients are likely to develop it. Any kind of core
decompression / bone grafting is a surgical attempt at
preventing /postponing this event. These joint salvage
procedures ( according to literature) achieves their goal in
about 30 - 50% of cases.
The rest of the collapse (which at times is confused with
primary AVN collapse )even by medical personnel is actually
secondary mechanical collapse and this occurs because of 3
factors:
1.hip stiffness, ( more the
stiffness the more the likelyhood of secondary collapse)
2.wrong biomechanics leading to point loading.
3.soft bone ( non wt bearing and NSAID abuse).
However once resurfacing is done secondary collapse will not
continue as the normal biomechanics and range of movement is re established. The
portion that is already collapsed ( primary or secondary) has to be taken out
and substitued with cement or bone graft at the time of surgery. This is a
simplisitic explanation for peaple not familiar with the concept. However this
does not represent the complete story.
Please read on if you are a medical personnel.
The 3rd type of collapse that can occur is specific to resurfacing and is called
as 'Global AVN' tertiary collapse ,or delayed primary failure of resurfacing. In
this the resurfaced head slowely tilts and falls off over a period of months.
This is the number one concern today in the field of hip resurfacing. There are
many theories as to why this occurs but the most plausible one is that it is
procedure induced and it involves disturbing the soft tissues of the neck and
the head-neck junction of the femur ( not the head of femur) at the time of
surgery. One must keep in mind that AVN occurs in individuals following pretty
trivial reasons like a fall, a single dose of steroid or surgery in the vicinity
of the hip joint like intramedullary nailing of the femur. To assume that the
varied approaches described for resurfacing ( anterior , lateral , posterior &
trochanteric osteotomy) will not cause AVN in the femoral head is naive. It is
now increasingly becoming obvious that Apical , sectoral primary AVN is caused
during the surgical approach in a very significant proportion of patients of any
surgeon's series of hip resurfacings. However, this is not of any consequence
and does not compromise the result.
In summary- the primary, sectoral classical AVN occurs in a majority of
resurfacings during the surgical exposure even in cases which did not have AVN
to begin with. However with the usage of low viscosity cement one performs a 'capituloplasty'
on the head, similar to the vertebroplasty done in the spinal vertabrae with the
injection of cement. This transforms the material under the resurfacing head
into a composite of live bone, dead bone and cement. If this composite is
seated on a vascular and biologically favourable neck and head neck junction ,
then this composite performs well. (The biological status of the neck and head
neck junciton is similar to health of a fracture fragment in fracture plating
surgery.ie Soft tissue cover of a bone fragment is essential for the end
arteries to supply no matter from where the blood is coming from) However for
some resion the neck capsule and soft tissues get damaged then one gets 'global
AVN' and the component drifts and fails. - termed as delayed primary failure .
This is independent of the fact as to whether primary , sectoral AVN in the head
was present before surgery or occured during the time of the surgery.
Therefore , resurfacings in AVN are no different from
resurfacings done for other indications. However if secondary collapse has been
left for too long it destroys the femoral head bone stock completely precluding
hip resurfacing. If there is sufficient bone stock at the time of surgery a AVN
resurfacing is likely to perform as well as any other resurfacing. The 185 AVN
resurfacing represents roughly half of my series of about 400 cases.
Explain
Acetabular Bone Loss
One of my patients from India who has had a resurfacing,
briefed me on the current discussion in the surfachippy
forum regarding Dr. Klappers opinion of losing acetabular
bone in an attempt to preserve femoral head bone in
resurfacing. He wanted to know my opinion and I thought it
would be appropriate for me to post my answer in this forum.
Dr. Klapper's opinion is way off the mark. The acetabular
size is the most important factor which determines the
choice of femoral head size in resurfacing and one never
removes more acetabular bone in hip resurfacings. In other
words if I would be performing a conventional hip
replacement on a given patient instead of resurfacing, I
would be using precisely the same size acetabular component
in both the surgeries.
I would go as far as saying that if we are taking out more
acetabular bone in resurfacing than in conventional hip
replacement , then in my opinion there is no role for
resurfacing and it must be discontinued immediately.
Acetabular conservation is as important if not more than
femoral bone conservation and all resurfacing surgeons
recognize and acknowledge this fact. The ability to put
large heads in resurfacing stems from the fact that thin
shelled acetabular components are possible with the modern
metal on metal bearings. However when one uses polyethylene
it has to have a large thickness ,which in turn reduces the
femoral head diameter, (assuming the acetabular outer shell
diameter remains the same). The same argument holds true for
ceramic on ceramic bearing to a lesser extent and therefore
slightly large femoral head sizes than metal on poly is
possible. However an anatomical size is currently possible
only with metal on metal bearings.
I strongly object to the terminology of "large or jumbo head
metal on metal hip replacement" that some surgeons use to
describe the current versions of the total hip replacements
which employ the same metal on metal bearing used in
resurfacings. I point out in all my lectures that this
variety of total hip replacement is the anatomical head
replacement giving the same natural size (of the femoral
head and the acetabulum) that the patient has in other
normal hip and the conventional THR are indeed small head
hip replacements. One must never lose this perspective. I
hope this helps to clear the sudden doubt that was cast on
the hip resurfacing principle recently.
I am honored that some of my overseas patients have got
together and made a plaque in appreciation of our hip
surgery team and a donation for the Jay Coulter fund.
Gary Klein has come back to Chennai to get his second hip
done. He brought the plaque and the donation.
I have attached a picture of the plaque.
With best regards
Vijay bose
chennai
Asian Regional
Center for Hip Resurfacing (ARCH)
Website
