Latest Scientific report from the British Medical Journal

[dwbitt]

The Dec 1 edition of the BMJ contains a study done by Dr. Art Sedrakyan of the Weill Cornell Medical College indicating MoM implants offer "no clear advantage of one of these products over another in terms of effectiveness, but there is evidence of a potential for harm associated with metal-on-metal implants."

http://group.bmj.com/group/media/latest-news/new-hip-implants-no-better-than-traditional-implants/?searchterm=hip%20implants

It would be interesting to hear from the Resurfacing community regarding these findings.

Dave

[Dannywayoflife]

As far as I'm concerned the main issue with mom or coc or any combinations there of is down to the surgeons implantation. The metal on plastic or ceramic on plastic is far more forgiving with relation the bad placement where as the mom devices rely on thick film fluid lubrication to work as designed. This cannot ever be acheved with plastic because the surface is too rough.
The mom bearing used in the bhr is no accident and has a much longer track record than 14 years. When being designed the designers looked at the materials used in previous mom thrs the ring and farrar hips.
When it was researched they discovered that this metallurgy had the ability for serious longevity out to 40 years. It also turned out that the vast majority of the failures were down to inconsistent engineering which nower days isn't a problem.
Also don't forget the first "psudotumor" was seen in a metal on plastic thr.
If these devices are implanted correctly the wear is phenomenally low.
Danny

[Woodstock Hippy]

I read the article twice and I just don't think it says very much.  It's like they are taking both sides of the debate so they can be sure that they are on the right side but here:

''They found that functional outcomes (ability to carry out usual daily activities) and general quality of life scores were no different between patients with the new metal on metal or ceramic on ceramic hip implants compared with traditional hip implants.''

I think they miss the boat.  As far as functional outcomes go they have to look at what the patient who goes for HR wants.  We want to be athletes again.  Most of us would feel disabed with a total hip replacement.  I know I would and that's why I left my first hip doctor and found someone to give me back my athletic life.

[Luanna]

It would be great if we had a registry here in the US. It provides so much data. I have metal on new cross-linked polyethylene and so far so good. It's only been 15 weeks so I'm hoping it will wear quite a bit longer!!  ;) 

The report is specifically referring to THRs. If they could cull out the data for HRs that might be more relevant to our population. Maybe they can generalize to HRs?

Danny, my device also relies on synovial fluid to work properly. The poly they make now is extremely smooth. I wanted metal on metal for more longevity but my surgeon would not do that mostly because of my small bones. He and Mr. McMinn are experimenting with the implants I now have for women like me. Time will tell. Guess you could say I'm sort of a guinea pig.

I thought the report was too general to draw any conclusions. I'd like to work with the raw data on HRs and see what turns up. But it's good to see that researchers are concerned with hip surgeries and working to better understand how to improve implants.

Luanna

[Dannywayoflife]

Luanna, I hope that it works great for you!! How come they use the Polly in small boned lady's though? Surely they have the right sizes to make mom work?

[Luanna]

Danny,
Well, I'm seeing my surgeon on Wed. and will ask him again. I don't want to misquote him but from what I recall it has to do with metalosis in small boned women being more prevalent then in larger boned women and men.

I'll get more info and post it later next week. I don't have the data that he shared with me and can't recall the stats and reasoning for my implants. But it was compelling. Oh dear.... memory is the first thing to go .  ;)

Luanna

[Dannywayoflife]

I'd be interested to hear what the reasoning is.
Danny

[Luanna]

This is a good start Danny. It takes a while for the file to open. But it is his article based on his research and experience about hip resurfacing for small boned women. I'll get more specifics for you next week. Article: Polyethelene Hip Resurfacing for Women by James W. Pritchett MD.

http://www.pritchettorthopedics.com/articles/women_hip_resurfacing.pdf

Luanna

[ScubaDuck]

Disclaimer- I have only read the article once and have not looked at the studies he references yet.

1.  I am suspect when "research" uses sensational adjectives and adverbs to sell their conclusions.  The use of the terms indicates a bias against MoM.
2.  If they truly want to look at bearing surface materials they need to remove the HUGE variables of design and surgeon.  For example, what happens if you remove the ASR data from their studies?
3.  Even after lots of sensational language they conclude that the study is incomplete and lacks data.

I will be reading this again when I have time to dissect it closer.  I can't help myself since I have a math degree.   :)

Dan

[Dannywayoflife]

Maths degree! That's awesome! I couldn't even pass my high school maths exam! I'm dyslexic and it really effects my maths!
If you remember the thread I started about the 3 dimentional wear  a while back that you replied on. From reading further studies the data I supplied was slightly out. I now understand that the figures I gave related to migration. Which isn't all down to wear. The cup beds in slightly as does the cap in the first year or so. And that's included in that 0.2mm figure I gave I now understand more about the figures.

[jon]

Just read the report.  Did not impress me with much.  Considering the number of different devices which have been in use and the wide variances in surgeon capabilities, a general study strikes me as pretty useless.  I have become an ardent believer of (i) find the best guy (ii) using the best device. 

Will ask McMinn on Monday nonetheless.

[Dannywayoflife]

Jon he is a rather well qualified man to answer the question! 

[Baby Barista]

For you French Canadians out there... this report is merde! There, I said it.

This report includes failure data for the ASR, a faulty device. That would be like someone arguing that "being a vegetarian kills you"... by including cases of ecoli poisoning in their data set.

[Dannywayoflife]

For you French Canadians out there... this report is merde! There, I said it.

This report includes failure data for the ASR, a faulty device. That would be like someone arguing that "being a vegetarian kills you"... by including cases of ecoli poisoning in their data set.

Ha I like it!:-)

[Aerial]

I too like a scientific and research based approach.  When I found out I needed a hip replacement, I thought, no way, I'm too young (46).  Not to mention, I have been very physically active my whole life.  Not being able to do activities I like was impacting my quality of life.  A little research led me to resurfacing and a little more research to Dr. Gross.  He has a slew of research/data based studies out there which to me is impressive (real data from real people used to make decisions on now to proceed is about the best we can ask for....of course assuming a solid research design and use of statistics which the peer review process of top end journals requires).  I asked many questions about the ion issue and I felt very comfortable that with a skilled surgeon and proper placement this is not much of an issue today. This is something the medical community sort of had to learn by trial and error.  Although I feely badly for those who had their surgery in the "trial" period, we who have had surgery recently benefit from a more refined procedure that minimizes such risks.

[Dannywayoflife]

I think Jon sums it up well. Best surgeon with a well proven device and you shouldn't go far wrong!

[FlbrkMike]

This pretty much sums up their findings:

The authors conclude: “There is limited evidence regarding comparative effectiveness of various hip implant bearings, and the results do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional bearings.”

Translation:

They can't come to any statistical conclusion because there's not enough data.
What else is new?

Notice that they don't say the there any indication of disadvantage for the MOM or ceramic implants either.

The only way to generate that data is to keep performing the procedures and follow the results.

[obxpelican]

Ceramic and plastic implants in the past have had a very poor track record.  Then came the MOM, then came this misinformation about the MOM and psuedotumors.

In the past, plastic has had debris shedding issues leading to the same types of issues that MOM implants have had when they were mis-implanted.   Ceramic implants have had issues with the material cracking. 

To me MOM implants still seem to be the gold standard, assuming your implant was installed at a nominal angle.  Assuming your MOM implant is not shedding ions I cannot see why most of us won't have our implants for life.

Chuck

[dwbitt]

Woodstock, I think you have a good point:

''They found that functional outcomes (ability to carry out usual daily activities) and general quality of life scores were no different between patients with the new metal on metal or ceramic on ceramic hip implants compared with traditional hip implants.''

When patients are surveyed regarding daily activities there is little difference, THR is a good procedure for "daily activities" for the general population, but HR allows for "unlimited" activities, the patient questionnaires don't ask more than 'general quality of life' questions.

[curt]

     I think the direction of this theme is on track:  to wit we cannot know how average or how awesome the MOM implant is until we have medium to long range track records and a study group of similar quality (device type, cup angle, abnormalities, age, activity level, etc.). Unless you compare apples to apples things always get murky.
     I think too, that the activity and stress put on most THRs is probably less (maybe a lot less) than with HR patients.  Lets be honest, that's why most got them in the first place -  to be more active.  As Dr. Gross stated somewhat enthusiastically during my 6 weeks appointment (I paraphrase):  "If other hip doctors could see what most of my patients can do with an HR they wouldn't believe it". 
      It is my sincere hope that most of us here will be excellent long-term data for the longevity of our implants, regardless of the type.  Selfishly, I'm pulling for mine a little harder than most - my bad!

Curt