Re: German data on metal ions?

[Guest guest]

There are certainly plenty of BHR patients in this group. Can someone tell

us what the luting agent is they use to attach the femoral component? I

enquired by E-mail directly to the Birmingham site early on in my search for

information and got no response. Other sources told me that there is no

significant difference in technique or materials between Birmingham, Corin

or devices. I would be VERY interested to know if this is not the

case.

Early trials in the UK with non-cemented femoral component resulted in a 15%

failure rate and were deemed not reliable for further development. But if

those devices were used on patient groups including AVN and extremely

degenerated femurs as was common at that time, those failures may not be all

that meaningful.

It would seem that the current success rate with cemented femoral components

is so good that manufacturers see no reason to do much work on non-cemented

versions. But I know surgeons who would agree with any dentist who works

with implants that true boney ingrowth, or " osteointegration " as we in

dentistry call it, is preferable to cement. I would prefer to have a

cementless option.

I hope this discussion is not causing anxiety about resurfacing because it

uses cement on the femoral side. I fully plan on having resurfacing this

fall and have made a fairly educated assessment of the pros and cons of all

the available devices, materials and techniques. I don't know of a better

option that's currently available.

But I can't help but lobby the industry to improve it's product if it's

possible to do so. Educated patients who are concerned about the materials

being placed within their body's having discussions with the surgeons who

communicate their preferences to the manufacturers is the only way this will

happen.

Jeffery, you asked about crowns which is a bit off the discussion group's

topic but maybe not that unrelated since we're talking about prosthetic

devices and materials placed in patient's bodies.

<<Also, how long do crowns last? I remember one dentist saying that gold

crowns can last up to 50 or 60 years if properly installed. Is this really

true? My crowns are rated for 20 or so years, I think.>>

I expect mine to last longer then that! Crowns do not generally " wear out " .

Teeth that have crowns on them may be lost to gum disease or decay below the

crown. Good hygiene and regular checkups can help a crown last for a

lifetime. Besides, avoiding dental infection is important so you don't risk

losing your new hip prosthesis!

There, aren't you sorry you asked! : )

All the best,

Mike

[Guest guest]

After returning to the BHR resurfacing site I found the following references

to the fixation of the femoral head. It indicates to me that the femoral

component is indeed " cemented " in place....

<<Femoral component fixation:

<<The circumstances for perfect cement fixation with this femoral component

occur because of an open cancellous network, low viscosity cement and a high

injection pressure generated by advancing the component into position. On

sectioning we have seen excellent micro-interlock of cement into the

peripheral femoral head cancellous network. (Fig.58)

Although I would avoid the presence of " bone cement " if I had a choice there

is also reassuring evidence that it's use is very successful and that

healthy bone can coexist with methylmethacrylate resin.

<<In our pilot series of resurfacings the cemented cups performed poorly and

many went on to loosening and failure and required revision surgery.42 These

patients however had intact and well fixed femoral components and when these

components were converted to conventional total hip replacement this gave

the opportunity for studying the femoral head viability.(Fig.58)

The site also gives the following as evidence that the bone within the head

of the femur remains vital since living bone metabolism must be occuring for

the tetracyline to be incorporated within the bone.

<<This specimen shows Tetracycline uptake on the surface of the trabeculae

in the femoral head under ultra-violet light confirming femoral head

viability.(Fig.61)

I wish to repeat that I believe resurfacing to be the best choice available

for the younger more physically active patient... but I also want to

encourage manufacturers to continue development of improved versions of

their product that do not require a cement interface between bone and metal.

Now, I'll climb down off my soapbox and give it a rest,

Mike

[Guest guest]

Dr Gross will have available for trial non cemented femoral components he

helped design I believe in August. I hope this information helps you

...

Re: Re: German data on metal ions?

> There are certainly plenty of BHR patients in this group. Can someone tell

> us what the luting agent is they use to attach the femoral component? I

> enquired by E-mail directly to the Birmingham site early on in my search

for

> information and got no response. Other sources told me that there is no

> significant difference in technique or materials between Birmingham, Corin

> or devices. I would be VERY interested to know if this is not the

> case.

>

> Early trials in the UK with non-cemented femoral component resulted in a

15%

> failure rate and were deemed not reliable for further development. But if

> those devices were used on patient groups including AVN and extremely

> degenerated femurs as was common at that time, those failures may not be

all

> that meaningful.

>

> It would seem that the current success rate with cemented femoral

components

> is so good that manufacturers see no reason to do much work on

non-cemented

> versions. But I know surgeons who would agree with any dentist who works

> with implants that true boney ingrowth, or " osteointegration " as we in

> dentistry call it, is preferable to cement. I would prefer to have a

> cementless option.

>

> I hope this discussion is not causing anxiety about resurfacing because it

> uses cement on the femoral side. I fully plan on having resurfacing this

> fall and have made a fairly educated assessment of the pros and cons of

all

> the available devices, materials and techniques. I don't know of a better

> option that's currently available.

>

> But I can't help but lobby the industry to improve it's product if it's

> possible to do so. Educated patients who are concerned about the materials

> being placed within their body's having discussions with the surgeons who

> communicate their preferences to the manufacturers is the only way this

will

> happen.

>

> Jeffery, you asked about crowns which is a bit off the discussion group's

> topic but maybe not that unrelated since we're talking about prosthetic

> devices and materials placed in patient's bodies.

>

> <<Also, how long do crowns last? I remember one dentist saying that gold

> crowns can last up to 50 or 60 years if properly installed. Is this really

> true? My crowns are rated for 20 or so years, I think.>>

>

> I expect mine to last longer then that! Crowns do not generally " wear

out " .

> Teeth that have crowns on them may be lost to gum disease or decay below

the

> crown. Good hygiene and regular checkups can help a crown last for a

> lifetime. Besides, avoiding dental infection is important so you don't

risk

> losing your new hip prosthesis!

>

> There, aren't you sorry you asked! : )

>

> All the best,

>

> Mike

>

>

>

>

[Guest guest]

----- Original Message -----

> Dr Gross will have available for trial non cemented femoral components he

> helped design I believe in August. I hope this information helps you

> ..

Thanks , I will have to check in to this. I could be very attractive

as an alternative for me.

Mike

[Guest guest]

I am wondering what is the difference between the internal surface

finishes of the inside femoral dome between the cemented and the non-

cemented types. (And the centering pin).

Also the PMMA cement (I presume used)has most of its research done

with the THR stems cementing to compact bone. The femoral head is

cancellous bone, a different physiological structure.

> Dr Gross will have available for trial non cemented femoral

components he

> helped design I believe in August. I hope this information helps you

> ..

>

> Re: Re: German data on metal ions?

>

>

> > There are certainly plenty of BHR patients in this group. Can

someone tell

> > us what the luting agent is they use to attach the femoral

component? I

> > enquired by E-mail directly to the Birmingham site early on in my

search

> for

> > information and got no response. Other sources told me that there

is no

> > significant difference in technique or materials between

Birmingham, Corin

> > or devices. I would be VERY interested to know if this is

not the

> > case.

> >

> > Early trials in the UK with non-cemented femoral component

resulted in a

> 15%

> > failure rate and were deemed not reliable for further

development. But if

> > those devices were used on patient groups including AVN and

extremely

> > degenerated femurs as was common at that time, those failures may

not be

> all

> > that meaningful.

> >

> > It would seem that the current success rate with cemented femoral

> components

> > is so good that manufacturers see no reason to do much work on

> non-cemented

> > versions. But I know surgeons who would agree with any dentist

who works

> > with implants that true boney ingrowth, or " osteointegration " as

we in

> > dentistry call it, is preferable to cement. I would prefer to

have a

> > cementless option.

> >

> > I hope this discussion is not causing anxiety about resurfacing

because it

> > uses cement on the femoral side. I fully plan on having

resurfacing this

> > fall and have made a fairly educated assessment of the pros and

cons of

> all

> > the available devices, materials and techniques. I don't know of

a better

> > option that's currently available.

> >

> > But I can't help but lobby the industry to improve it's product

if it's

> > possible to do so. Educated patients who are concerned about the

materials

> > being placed within their body's having discussions with the

surgeons who

> > communicate their preferences to the manufacturers is the only

way this

> will

> > happen.

> >

> > Jeffery, you asked about crowns which is a bit off the discussion

group's

> > topic but maybe not that unrelated since we're talking about

prosthetic

> > devices and materials placed in patient's bodies.

> >

> > <<Also, how long do crowns last? I remember one dentist saying

that gold

> > crowns can last up to 50 or 60 years if properly installed. Is

this really

> > true? My crowns are rated for 20 or so years, I think.>>

> >

> > I expect mine to last longer then that! Crowns do not

generally " wear

> out " .

> > Teeth that have crowns on them may be lost to gum disease or

decay below

> the

> > crown. Good hygiene and regular checkups can help a crown last

for a

> > lifetime. Besides, avoiding dental infection is important so you

don't

> risk

> > losing your new hip prosthesis!

> >

> > There, aren't you sorry you asked! : )

> >

> > All the best,

> >

> > Mike

> >

> >

> >

> >

[Guest guest]

The inside of cemented domes have a smooth but unpolished, " sandblasted "

appearing finish. I would expect non-cemented dome to receive the same

surface treatment that the manufacturer uses on it's non-cemented acetabular

cups.

Midland seems to think PMMA works well with cancellous bone as indicated in

the following from their site...

<<The circumstances for perfect cement fixation with this femoral component

occur because of an open cancellous network, low viscosity cement and a high

injection pressure generated by advancing the component into position. On

sectioning we have seen excellent micro-interlock of cement into the

peripheral femoral head cancellous network. (Fig.58)>>

It's a little hard for me to accept that bone can live indefinitely against

PMMA. That's why I lobby so hard for a cementless option.

Mike

Re: German data on metal ions?

> I am wondering what is the difference between the internal surface

> finishes of the inside femoral dome between the cemented and the non-

> cemented types. (And the centering pin).

>

> Also the PMMA cement (I presume used)has most of its research done

> with the THR stems cementing to compact bone. The femoral head is

> cancellous bone, a different physiological structure.

[Guest guest]

What is strange to me is that he oldest (I assume) and mature

fabricator of resurfs uses cement. The other 3 producers don't.

Does BHR know something the others haven't fully realized yet? The

cement adds another degree of complexity to the process and shouldn't

(wouldn't?) be used if is at all not necessary. Seems like they

should 'fess up with some kind of white paper (or point to some

research on this).

Don W

> The inside of cemented domes have a smooth but

unpolished, " sandblasted "

> appearing finish. I would expect non-cemented dome to receive the

same

> surface treatment that the manufacturer uses on it's non-cemented

acetabular

> cups.

>

> Midland seems to think PMMA works well with cancellous bone as

indicated in

> the following from their site...

>

> <<The circumstances for perfect cement fixation with this femoral

component

> occur because of an open cancellous network, low viscosity cement

and a high

> injection pressure generated by advancing the component into

position. On

> sectioning we have seen excellent micro-interlock of cement into the

> peripheral femoral head cancellous network. (Fig.58)>>

>

> It's a little hard for me to accept that bone can live indefinitely

against

> PMMA. That's why I lobby so hard for a cementless option.

>

> Mike

>

> Re: German data on metal ions?

>

>

> > I am wondering what is the difference between the internal surface

> > finishes of the inside femoral dome between the cemented and the

non-

> > cemented types. (And the centering pin).

> >

> > Also the PMMA cement (I presume used)has most of its research done

> > with the THR stems cementing to compact bone. The femoral head is

> > cancellous bone, a different physiological structure.

[Guest guest]

Hi Mike,

Can I ask why this may be so............? I know little about the chemical

interconnections created but would wonder why the manufactures would propose

something that had a long term problem? Or is the long term that many years

that few of us would have reason to worry..........??? i.e. I only need

about 25 years out of my hip......... smile.

Edith LBRH Dr. L Walter Sydney Australia 8/02

>

> It's a little hard for me to accept that bone can live indefinitely

against

> PMMA. That's why I lobby so hard for a cementless option.

>

> Mike

[Guest guest]

Don,

As far as I know all resurfacing appliances have cemented femoral

components. This seems to work fine, at least for the current subjects with

histories or ten or more years. I fully expect to have a cemented femoral

component myself, unless a cementless one becomes available before

September, and I have great confidence in that technique.

That said, on a histological level, a cemented device will always have

connective tissue between the bone and the cement. This soft tissue can

allow movement and is subject to loosening under stress. A cementless device

will have bone growing in (virtually) direct contact with the metal. In fact

bone grows in and around the retentive surface cast in to the device. The

device and the bone are pretty much fused together.

This is why cementless acetabular cups and total hip stems are much better

in more active patients. My wife described the difference in dental terms

last night at dinner. She said, " It's like the difference between a

temporary shell crown that is hollow and fits the tooth because it's filled

with cement and a crown that is cast to fit the tooth intimately. "

There are some tough problems in making cementless femoral components. For

one thing, they must " fit " both the opposing acetabular component and the

prepared head of the femur. If there are five sizes of acetabular cups and

five sizes of femoral heads, suddenly they must produce twenty five

different femoral components to accommodate the different possibilities.

Just the casting and finishing of the inside of the femoral component is

more complicated, i.e.: expensive for cementless devices. And finally, the

fit on the femoral head becomes much more crucial. The head of the femur

must be in good condition and the surgeon must not only have exceptional

skill, he must take more TIME to make sure the fit is perfect. Make no

mistake, a change that requires more time in the OR will not be popular

among most surgeons.

So it's less expensive and take less time in surgery to use cemented femoral

components. And right now, there are nothing but glowing reports on

cemented devices so why " bother " ? I think that the cement is the last " weak

link " in the design of the resurfacing device and is the next logical step

in refining and improving the technique. Only demanding " PITA " patients and

surgeons will motivate manufacturers to create an expensive new line of

products that are cementless.

Just my opinion,

Mike

Re: German data on metal ions?

> >

> >

> > > I am wondering what is the difference between the internal surface

> > > finishes of the inside femoral dome between the cemented and the

> non-

> > > cemented types. (And the centering pin).

> > >

> > > Also the PMMA cement (I presume used)has most of its research done

> > > with the THR stems cementing to compact bone. The femoral head is

> > > cancellous bone, a different physiological structure.

>

>

>

>

[Guest guest]

There has been a lot of conversation on cemented and non cemented hip surgery

over the years.

This applies to THR and Resurfacing. If you care to investigate the Swedish

Registry (English language version is a couple of years older than the Swedish

version) and other sources (e.g. NICE report) you'll find the following is a

consensus of various opinions. Like everything in this world there are no hard

and fast rules and not everything is set in concrete (excuse the pun!).

1. Non cemented THR is used to facilitate an easier replacement after 10/20

years or whenever it is needed. They are consequently used on younger patients

and the chance of a revision is higher than cemented.

2 Cemented THR are used for longer life, statistically, but revision is more

difficult. It is awkward to remove the cement and therefore more bone has to be

removed making it more difficult for further operations. In Sweden 158,614

(revision rate 7%) primary THR's were cemented and just 5,559 (revision rate

13%) uncemented between the dates of 1979 and 1998. Source of data

http://www.jru.orthop.gu.se/archive/AAOS-2000-NHR.pdf.

This document is updated annually and presented to the AAOS. It is held as a

major reference document the world over.

3. Resurfacing, whether cemented or not, gives you a length of time before you

reach stage 1 of a THR. Again in history there is data that indicates that

cementation improved the chances against revision. Most people who have had

resurfacing and their surgeons are optimistic that the vast majority will never

see a THR.

Cementing takes some of the accuracy of the surgeon out of the equation.

The cement/non cement issue has been going on in the UK & elsewhere for many

many years. Data as stated in the Swedish Registry shows we are on the right

track.

Rog L & R BHR Ronan Treacy

Re: German data on metal ions?

> I am wondering what is the difference between the internal surface

> finishes of the inside femoral dome between the cemented and the non-

> cemented types. (And the centering pin).

>

> Also the PMMA cement (I presume used)has most of its research done

> with the THR stems cementing to compact bone. The femoral head is

> cancellous bone, a different physiological structure.

[Guest guest]

Hi ,

You mention that getting the femoral top ready would take a good deal

longer.............. I immediately thought that this is more than what the

OS crowd want.......... The time one lays open on a table is a factor in

determining the chances of good old golden staff and its infectious

mates........ quite a different ball game to a dentist's workshop...........

that's without the cost the patient would be up for as an added

extra.............. and by the sounds of it, it could take some time to get

the bone to grow into the femoral component and one would spend that

potentially long period unable to use the leg............ I swim with a

woman who is having hassles just getting her leg bones to knit after a break

18 months ago......... so it isn't a given that bones will just grow

.............. and they may even have the interesting problem of being able

to tell how much bone had grown under the metal shell.

As I understand it part of the beauty of Resurface has been the ability to

be 'up and at em' so to speak....... with recovery being more dependant on

the state of the muscles than how fast one may grow bones........... Thus I

would be thinking that it would be more an issue of them perfecting cements

that most resembled bones and/or permitted bone to replace it in the course

of time..........???

Edith LBHR Dr. L Walter Sydney Australia 8/02

>

> Just the casting and finishing of the inside of the femoral component is

> more complicated, i.e.: expensive for cementless devices. And finally, the

> fit on the femoral head becomes much more crucial. The head of the femur

> must be in good condition and the surgeon must not only have exceptional

> skill, he must take more TIME to make sure the fit is perfect. Make no

> mistake, a change that requires more time in the OR will not be popular

> among most surgeons.

>

> So it's less expensive and take less time in surgery to use cemented

femoral

> components. And right now, there are nothing but glowing reports on

> cemented devices so why " bother " ? I think that the cement is the last

" weak

> link " in the design of the resurfacing device and is the next logical step

> in refining and improving the technique. Only demanding " PITA " patients

and

> surgeons will motivate manufacturers to create an expensive new line of

> products that are cementless.

>

> Just my opinion,

>

> Mike

[Guest guest]

,

I read through the citation you gave but I remain inconvinced that cemented

devices have any over all advantages* over non-cemented devices. I'm sure if

you placed non-cemented devices in ten - forty year old patients the

revision rate would be quite high. On the other hand, ten - 80 year patients

receiving cemented stems would require virtually no revisions. Age, demand

and even technological advances in recent years need to be included in the

equation.

Statistically, the cemented devices appear to be more failure prone but in

reality they are not used in young patients because they are easier to

revise. They are used in young patients because this patient group puts more

demands on their THRs and non-cemented devices are stronger and less prone

to mechanically separate from bone.

*There are very good indications for cemented devices and they work very

well if used appropriately. Resurfacing is one because the primary force on

the resurfacing dome is compression. The acetabular cup on the other and is

stressed with with verious tipping and torquing actions that require the

strength of bone growth into metal prosthesis to keep the cup in place

during tension.

I don't object to the use of cement in resurfacing, I just like the idea of

boney ingrowth without cementation better then the cemented option. I also

think that this will be the next major advance in resurfacing and will be

very common in the not too distant future.

It sounds like this subject has been gone over pretty thorougly here in the

past and I don't think that the difference between cemented and non-cemented

domes in resurfacing is significant enough to get upset over. The wonderful

thing is that resurfacing works and the ongoing traffic on this board is

testiment to that fact

Mike

[Guest guest]

Re: Re: German data on metal ions?

> Hi ,

>

> You mention that getting the femoral top ready would take a good deal

> longer..............

Yes, and require more skill and care from the surgeon!!!

I immediately thought that this is more than what the

> OS crowd want..........

And this resistance is very evident any time a new technique in introduced,

witness, the knee-jerk dissmissal of resurfacing by many surgeons reported

on this list!!!

> The time one lays open on a table is a factor in

> determining the chances of good old golden staff and its infectious

> mates........

Resurfacing and THRs are pretty fast paced surgeries, often over in 20-30

minutes (OS time), I don't think an exta 5 minutes would really create that

much additional mortality

> quite a different ball game to a dentist's workshop...........

I have a " workshop " in my garage, at my office I have five operatories that

are used for many minor surgerys each day.

> that's without the cost the patient would be up for as an added

extra..............

Aren't many of our resurfacing friends willing to pay extra, or even risk

outright refusal of insurance coverage in order to have the benifits of

resurfacing over THR?

> and by the sounds of it, it could take some time to get

> the bone to grow into the femoral component and one would spend that

> potentially long period unable to use the leg............

Very good question that I don't know the answer to but I haven't heard of

this kind of complaint with cementless THRs. Resurfacing should be even

quicker since there's little torque or tension involved, don't you think?

>I swim with a

> woman who is having hassles just getting her leg bones to knit after a

break

> 18 months ago......... so it isn't a given that bones will just grow

Yes, patients with circulatory problems, diabetes, smokers (yes I said

smokers), or anyone with reduced healing potential or compromised immune

systems should approach any of these procedures with extreme caution and

with the detailed evaluation and consultation of appropriate specialists.

> ............. and they may even have the interesting problem of being able

> to tell how much bone had grown under the metal shell.

But wait a minute, how is this different than the situation with current

cemented devices? It's a good point though! It parallels dentistry's

inability to detect decay under a gold crown with x-rays. In my practice I

take every precaution I can to be sure there is no residual decay in the

tooth being prepped and I'm very careful to create a crown that fits

properly without leakage or rough edges that could facilitate new decay. An

OS doing a cementless resurfacing would have to have a " healthy " femoral

head to work on. It must fill all the space whithin the dome and have good

circulation for bone growth. Patient selection... and OS selection become

more critical, but there are all the other options still available for

marginal situations. I'm not suggesting we eliminate any of those!

> As I understand it part of the beauty of Resurface has been the ability to

> be 'up and at em' so to speak....... with recovery being more dependant on

> the state of the muscles than how fast one may grow bones...........

I think you're right that there should be a longer recovery involved with

non-cemented resurfacing. That would be a consideration for the patient and

their surgeon to discuss pre-op. Again, I don't think this is a major

problem in THRs.

> Thus I

> would be thinking that it would be more an issue of them perfecting

cements

> that most resembled bones

That would be a major improvement but what can you mix up in a cup and pour

into a device that resembles bone but won't break like plaster? If you

invented such a material and could get it approved for use in human

patients, you would be a very wealthy person. Go for it!

>and/or permitted bone to replace it in the course of time..........???

This would be wonderful! In dentisty, we use many types of " bone grafting "

materials that do just that. Unfortunately, to build bone, you must have

living cells and a fairly porous matrix so that blood can nourish the

growing tissue. We have to cover and protect these graft sites for months

without function before good strong bone has been formed. That would really

limit your post op activites!

> Edith LBHR Dr. L Walter Sydney Australia 8/02

Edith, as you know e-mail sometimes makes our message sound harsh or flip

when that's not what we meant. I respect your points (or I wouldn't have

just spent an hour of my life responding)... and I hope you don't take

offense at my responses. I'm just trying to muddle through these issues like

everyone else in the group.

I still think that having a cementless option for resurfacing would be

valuable and useful for those who prefer it and the surgeons willing to use

it. It may be just an incremental improvement, after all present resurfacing

techology is very successful, but I don't understand the adamant resistance

I hear from some to the concept.

At any rate, I envy you your new hip. I wish mine was done already, cemented

or not. This week I graduated to a cane and have not been sleeping well and

am definitely not my usual happy go lucky self. I certainly appreciate the

light at the end of the tunnel everyon on the list, gives us pre-opies!

Thankyou!!!!

Mike

[Guest guest]

Hi ,

Thanks for taking the time to reply............ and no I rarely get offended

with emails..........as I realise that there is this problem with not being

able to see the others expression, thus a lot of irony often gets

misinterpreted etc...........smile.

I did appreciate your answers....... and yes I would support an uncemented

resurface too if such a beast was on offer......... the less foreign matter

in ones body the better if for no other reason.........

Long before I realised that there existed this wonderful OS who would chip

my fused hip apart and put a BHR on it, I used to dream of a clone situation

where one got injected with something that would make a hip........ I guess

that would be the ultimate, followed closely by something that made the

cartledge grow back on the bones...........and some work is being done there

isn't there??? I guess all existing things take steps back from these

ideals...... and until they arrive we have to make do with what is

there.......... I sure enjoy my BHR as opposed to a fused hip........... and

as I was always refused a THR I am sure glad medical science progressed this

far............smile........and because I was refused a THR (over many years

via many doctors) I do see the BHR as a progression........

Thanks again for your reply............ and I do hope everything goes well

for your forthcoming op so you can join the rest of us lucky mob in getting

on with a great life............smile........ and yes I think I too found

the last few weeks the very hardest to endure - one just wants it all over

and done with and I think the strain of coping with pain etc gets too much

to bear any longer............ or perhaps the pretence of being able to deal

with it slips away and one gets worse by the minute........... But it too

will be a memory soon...........

BTW I have 4 crowns and I think they are a pretty good invention

too............smile. I was sure glad my dentist could fit them and allow me

to keep the teeth instead of dentures............

Edith LBHR Dr. L Walter Sydney Australia 8/02

> >

> > You mention that getting the femoral top ready would take a good deal

> > longer..............

>

> Yes, and require more skill and care from the surgeon!!!

>

> I immediately thought that this is more than what the

> > OS crowd want..........

>

> And this resistance is very evident any time a new technique in

introduced,

> witness, the knee-jerk dissmissal of resurfacing by many surgeons reported

> on this list!!!

>

> > The time one lays open on a table is a factor in

> > determining the chances of good old golden staff and its infectious

> > mates........

>

> Resurfacing and THRs are pretty fast paced surgeries, often over in 20-30

> minutes (OS time), I don't think an exta 5 minutes would really create

that

> much additional mortality

>

> > quite a different ball game to a dentist's workshop...........

>

> I have a " workshop " in my garage, at my office I have five operatories

that

> are used for many minor surgerys each day.

>

> > that's without the cost the patient would be up for as an added

> extra..............

>

> Aren't many of our resurfacing friends willing to pay extra, or even risk

> outright refusal of insurance coverage in order to have the benifits of

> resurfacing over THR?

>

> > and by the sounds of it, it could take some time to get

> > the bone to grow into the femoral component and one would spend that

> > potentially long period unable to use the leg............

>

> Very good question that I don't know the answer to but I haven't heard of

> this kind of complaint with cementless THRs. Resurfacing should be even

> quicker since there's little torque or tension involved, don't you think?

>

> >I swim with a

> > woman who is having hassles just getting her leg bones to knit after a

> break

> > 18 months ago......... so it isn't a given that bones will just grow

>

> Yes, patients with circulatory problems, diabetes, smokers (yes I said

> smokers), or anyone with reduced healing potential or compromised immune

> systems should approach any of these procedures with extreme caution and

> with the detailed evaluation and consultation of appropriate specialists.

>

> > ............. and they may even have the interesting problem of being

able

> > to tell how much bone had grown under the metal shell.

>

> But wait a minute, how is this different than the situation with current

> cemented devices? It's a good point though! It parallels dentistry's

> inability to detect decay under a gold crown with x-rays. In my practice I

> take every precaution I can to be sure there is no residual decay in the

> tooth being prepped and I'm very careful to create a crown that fits

> properly without leakage or rough edges that could facilitate new decay.

An

> OS doing a cementless resurfacing would have to have a " healthy " femoral

> head to work on. It must fill all the space whithin the dome and have good

> circulation for bone growth. Patient selection... and OS selection become

> more critical, but there are all the other options still available for

> marginal situations. I'm not suggesting we eliminate any of those!

>

> > As I understand it part of the beauty of Resurface has been the ability

to

> > be 'up and at em' so to speak....... with recovery being more dependant

on

> > the state of the muscles than how fast one may grow bones...........

>

> I think you're right that there should be a longer recovery involved with

> non-cemented resurfacing. That would be a consideration for the patient

and

> their surgeon to discuss pre-op. Again, I don't think this is a major

> problem in THRs.

>

> > Thus I

> > would be thinking that it would be more an issue of them perfecting

> cements

> > that most resembled bones

>

> That would be a major improvement but what can you mix up in a cup and

pour

> into a device that resembles bone but won't break like plaster? If you

> invented such a material and could get it approved for use in human

> patients, you would be a very wealthy person. Go for it!

>

> >and/or permitted bone to replace it in the course of time..........???

>

> This would be wonderful! In dentisty, we use many types of " bone grafting "

> materials that do just that. Unfortunately, to build bone, you must have

> living cells and a fairly porous matrix so that blood can nourish the

> growing tissue. We have to cover and protect these graft sites for months

> without function before good strong bone has been formed. That would

really

> limit your post op activites!

>

> > Edith LBHR Dr. L Walter Sydney Australia 8/02

>

> Edith, as you know e-mail sometimes makes our message sound harsh or flip

> when that's not what we meant. I respect your points (or I wouldn't have

> just spent an hour of my life responding)... and I hope you don't take

> offense at my responses. I'm just trying to muddle through these issues

like

> everyone else in the group.

>

> I still think that having a cementless option for resurfacing would be

> valuable and useful for those who prefer it and the surgeons willing to

use

> it. It may be just an incremental improvement, after all present

resurfacing

> techology is very successful, but I don't understand the adamant

resistance

> I hear from some to the concept.

>

> At any rate, I envy you your new hip. I wish mine was done already,

cemented

> or not. This week I graduated to a cane and have not been sleeping well

and

> am definitely not my usual happy go lucky self. I certainly appreciate the

> light at the end of the tunnel everyon on the list, gives us pre-opies!

>

> Thankyou!!!!

>

> Mike

>

[Guest guest]

Mike,

I just gave you statistics.

How you interpret them is up to you as indeed it would be for anyone else.

..

I don't know whether the statistic I'm going to quote is going to upset people

but here goes - Please read

" In order to facilitate comparisons between different national registries,

identification of " key parameters " is important. Revision Burden (RB) is an

example of such a parameter. RB is the fraction of revisions and the total

number of primary and revision THR. The figures on this page show the revision

burden for cemented, uncemented and hybrid THR:s in Sweden in two time intervals

1979-2000 and 1992-2000. A wide variation is noted in revision burden. RB for

cemented prostheses 1979-2000 is 7.4% and for uncemented implants 27.3%

(1992-2000). This explains the reluctance to use uncemented implants among the

Swedish surgeons. "

The above is nothing to do with me. I'm only repeating a portion of the Swedish

Hip Registry 2002 which covers 1979-2000.

I repeat non of the above is anything else but statistics of a very reputable

AAOS accepted document.

Rog

Re: Re: German data on metal ions?

,

I read through the citation you gave but I remain inconvinced that cemented

devices have any over all advantages* over non-cemented devices. I'm sure if

you placed non-cemented devices in ten - forty year old patients the

revision rate would be quite high. On the other hand, ten - 80 year patients

receiving cemented stems would require virtually no revisions. Age, demand

and even technological advances in recent years need to be included in the

equation.

Statistically, the cemented devices appear to be more failure prone but in

reality they are not used in young patients because they are easier to

revise. They are used in young patients because this patient group puts more

demands on their THRs and non-cemented devices are stronger and less prone

to mechanically separate from bone.

*There are very good indications for cemented devices and they work very

well if used appropriately. Resurfacing is one because the primary force on

the resurfacing dome is compression. The acetabular cup on the other and is

stressed with with verious tipping and torquing actions that require the

strength of bone growth into metal prosthesis to keep the cup in place

during tension.

I don't object to the use of cement in resurfacing, I just like the idea of

boney ingrowth without cementation better then the cemented option. I also

think that this will be the next major advance in resurfacing and will be

very common in the not too distant future.

It sounds like this subject has been gone over pretty thorougly here in the

past and I don't think that the difference between cemented and non-cemented

domes in resurfacing is significant enough to get upset over. The wonderful

thing is that resurfacing works and the ongoing traffic on this board is

testiment to that fact

Mike

[Guest guest]

Mike,

In your discussion of cementing (or not)the femoral cup... The

part that impresses me is when Amstutz prepares the head (i.e., gives

the head a frustum shape) he also drills a series of (very close

together)many small holes around this head surface to " add to the

fixation area " . If I understand the PMMA cement, this acts more like

a cement and not a glue. So drilling these holes around the

periphery esentially weakens the head, but then to be filled with

cement to strengthen the head and/or to reduce torque effects.

Seems like if one wants a cementless cup, this requirement is in

the opposite way one would like the procedure to evolve.

Cheers,

Don W

>

> Re: Re: German data on metal ions?

>

>

> > Hi ,

> >

> > You mention that getting the femoral top ready would take a good

deal

> > longer..............

>

> Yes, and require more skill and care from the surgeon!!!

>

> I immediately thought that this is more than what the

> > OS crowd want..........

>

> And this resistance is very evident any time a new technique in

introduced,

> witness, the knee-jerk dissmissal of resurfacing by many surgeons

reported

> on this list!!!

>

> > The time one lays open on a table is a factor in

> > determining the chances of good old golden staff and its

infectious

> > mates........

>

> Resurfacing and THRs are pretty fast paced surgeries, often over in

20-30

> minutes (OS time), I don't think an exta 5 minutes would really

create that

> much additional mortality

>

> > quite a different ball game to a dentist's workshop...........

>

> I have a " workshop " in my garage, at my office I have five

operatories that

> are used for many minor surgerys each day.

>

> > that's without the cost the patient would be up for as an added

> extra..............

>

> Aren't many of our resurfacing friends willing to pay extra, or

even risk

> outright refusal of insurance coverage in order to have the

benifits of

> resurfacing over THR?

>

> > and by the sounds of it, it could take some time to get

> > the bone to grow into the femoral component and one would spend

that

> > potentially long period unable to use the leg............

>

> Very good question that I don't know the answer to but I haven't

heard of

> this kind of complaint with cementless THRs. Resurfacing should be

even

> quicker since there's little torque or tension involved, don't you

think?

>

> >I swim with a

> > woman who is having hassles just getting her leg bones to knit

after a

> break

> > 18 months ago......... so it isn't a given that bones will just

grow

>

> Yes, patients with circulatory problems, diabetes, smokers (yes I

said

> smokers), or anyone with reduced healing potential or compromised

immune

> systems should approach any of these procedures with extreme

caution and

> with the detailed evaluation and consultation of appropriate

specialists.

>

> > ............. and they may even have the interesting problem of

being able

> > to tell how much bone had grown under the metal shell.

>

> But wait a minute, how is this different than the situation with

current

> cemented devices? It's a good point though! It parallels dentistry's

> inability to detect decay under a gold crown with x-rays. In my

practice I

> take every precaution I can to be sure there is no residual decay

in the

> tooth being prepped and I'm very careful to create a crown that fits

> properly without leakage or rough edges that could facilitate new

decay. An

> OS doing a cementless resurfacing would have to have a " healthy "

femoral

> head to work on. It must fill all the space whithin the dome and

have good

> circulation for bone growth. Patient selection... and OS selection

become

> more critical, but there are all the other options still available

for

> marginal situations. I'm not suggesting we eliminate any of those!

>

> > As I understand it part of the beauty of Resurface has been the

ability to

> > be 'up and at em' so to speak....... with recovery being more

dependant on

> > the state of the muscles than how fast one may grow

bones...........

>

> I think you're right that there should be a longer recovery

involved with

> non-cemented resurfacing. That would be a consideration for the

patient and

> their surgeon to discuss pre-op. Again, I don't think this is a

major

> problem in THRs.

>

> > Thus I

> > would be thinking that it would be more an issue of them

perfecting

> cements

> > that most resembled bones

>

> That would be a major improvement but what can you mix up in a cup

and pour

> into a device that resembles bone but won't break like plaster? If

you

> invented such a material and could get it approved for use in human

> patients, you would be a very wealthy person. Go for it!

>

> >and/or permitted bone to replace it in the course of

time..........???

>

> This would be wonderful! In dentisty, we use many types of " bone

grafting "

> materials that do just that. Unfortunately, to build bone, you must

have

> living cells and a fairly porous matrix so that blood can nourish

the

> growing tissue. We have to cover and protect these graft sites for

months

> without function before good strong bone has been formed. That

would really

> limit your post op activites!

>

> > Edith LBHR Dr. L Walter Sydney Australia 8/02

>

> Edith, as you know e-mail sometimes makes our message sound harsh

or flip

> when that's not what we meant. I respect your points (or I wouldn't

have

> just spent an hour of my life responding)... and I hope you don't

take

> offense at my responses. I'm just trying to muddle through these

issues like

> everyone else in the group.

>

> I still think that having a cementless option for resurfacing would

be

> valuable and useful for those who prefer it and the surgeons

willing to use

> it. It may be just an incremental improvement, after all present

resurfacing

> techology is very successful, but I don't understand the adamant

resistance

> I hear from some to the concept.

>

> At any rate, I envy you your new hip. I wish mine was done already,

cemented

> or not. This week I graduated to a cane and have not been sleeping

well and

> am definitely not my usual happy go lucky self. I certainly

appreciate the

> light at the end of the tunnel everyon on the list, gives us pre-

opies!

>

> Thankyou!!!!

>

> Mike