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Dual mobility acetabular cup vs traditional implant #2

Discussion in 'Hip Replacement Pre-Op Area' started by Andy P, May 26, 2018.

  1. Andy P

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    I've been searching for articles on the dual mobility implant but found very little in respect to there usability. Its really good of you to pass on your experience

    So, I'm at a very similar crossroads, looking at the dual mobility it is difficult to understand how the bio-mechanics actually work, as the smaller bearing is around 22mm, which is a sphere much less than half of what one would have originally.

    So I'm just wondering how it functions in real life. Could I ask, does your walking/gait and running feel natural?

    My concern is whether to go for a large bearing implant that will give a more natural gait, or whether the dual mobility implant function in the same way.
     
  2. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    The dual mobility works by creating a double bearing surface which supposedly creates less stress, wear and greater security against dislocation. However, these claims are not supported by the stats published in the National JOint Registry 2017. In fact, the general consensus given is that all hip replacements are about equal in terms of good outcomes and longevity. The key issue with all joint replacements is not the device but the surgeon.

    May I ask where you are planning to have your hip done? I would be very happy to advise on a good surgeon if you wish. Here's some guidelines about Choosing a surgeon and a prosthesis

    And welcome to BoneSmart!
     
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  3. dapplega

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    Hi @Andy P - Speaking for myself (and unable to compare to traditional implant), my gait is back to normal. I didn't realize how bad I was walking before THR until folks comment that I'm walking a lot better post THR. I believe my ceramic head size was 28mm whereas seems standard size is 32mm for traditional implant. I believe my cup was 50mm. That means the dual mobility plastic portion is 11mm thick on the sides (for 22mm total) compared to 9mm with a traditional 32mm head... Now, there is dual wear but as others have said, the data doesn't fully exist yet... I saw 3 recommended OS in Seattle area and 2 of the three recommended the dual mobility. The other didn't as the long term data wasn't available...
     
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  4. dlp

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    I have a Stryker ADM X3 implant, which is dual-mobility. Next week will be 1 year since my (first) surgery, and I can basically say that I give it zero thought. It might be that my hips have been so bad that I don't remember "normal", but I honestly have to say that with this implant nothing feels "abnormal".
     
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  5. Andy P

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    Hi Josephine, thank you for replying to my message. I'm due to have surgery on the 28th July at Guys, London. I've seen a few surgeons so far and this one was the only one to actually communicate, I'm afraid Ive heard a lot of miss-truths in the last year, so decided to ask some previous patients to learn more. Its all a bit scary.

    Thanks for the detailed info Dapplega and Dip, the bearing then seems to be close to its native size them. Its difficult to get my head around at the moment.

    Dapplega, did the surgeons say why they preferred the DM joint? it does seem to be a quiet fashion thats creeping in, but i'm suspicious as to whether its just because of the low dislocation risk, and doesn't offer any other benefits.
     
    Last edited: Jun 26, 2018
  6. dapplega

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    @Andy P - well to be honest, I didn't ask as much then as I would now... My OS came highly recommended and this is what he uses... I guess I bought into the advice of pick your surgeon, not the implant... Now, I probably should have asked how long he has been using it and why exactly?... The lower dislocation risk I believe has been proven. So has the increased ROM. Both of those could be benefits to younger/active recipients... What isn't known is the longevity - will it wear faster with 2 articulating surfaces?... Registries so far show no measurable difference with a ceramic head and high cross linked poly... Note - these are my interpretations based on my research - others may differ... :) The whole THR thing from initial diagnosis to recovery can be very daunting... Let me know if you have any other questions that can help...
     
  7. Andy P

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    Thanks Dapplega, yes, it is very daunting indeed. I have tried asking several surgeons, but they get very frustrated very easily.

    The question I've put to two surgeons is one of bio-mechanics and neither wanted to talk about it. So my feeling is that they don't actually know or its way out of their experience. Imagining their position, they spend a decade learning how to apply a process, they have options, but these are all researched and approved beforehand. So their choices are a, b or c dependant on implant survival. And you're lucky if you have a choice (........speaking for them)

    Having researched a little on this subject there actually doesn't seem to be much specific interest in sophisticated research into variations of implant and biomechanics. Im guessing, they've only just got the survival rate up, so this is something else. With DM, again, Im guessing, as its not yet mainstream (in its current form, Highly crossed Poly x Ceramic), then there wont be many samples which can be studied.

    So, then is it a compromise, I know that 'large head' bearing (40mm +) are better for biomecanics, but there are wear issues over 36mm. So then DM comes somewhere in the middle of small and large. Its strange that its not discussed though

    I also wonder if they actually care either way.......
     
  8. dapplega

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    If I'm reading it correctly, in Australia about 1% of all THR's were DM. Over 5 years the revision rate was actually slightly lower than regular THR. At 15 years, ceramic on XPLE has the lowest overall revision rate...
    upload_2018-6-27_20-41-5.png
     
  9. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    Andy, that's hardly surprising! Some of the questions like this can't be answered simply and without launching into a lengthy treatise on physics, biomechanics and such, there is no easy way to provide an answer. And they have time constraints on them in their clinics too and might see around 10 or 15 people who want to ask the same or similar questions too. So generally they will cut to the chase and just show the patient a sample of the implant they intend to use which may or may not suffice.
    Nobody knows - not for sure. But we have a pretty good idea. There is often a myth given out freely to the younger patient that they will likely be facing a revision every 10 years or so but this is just a myth.

    I was in the operating theatre with the originator of modern hip replacements, Mr Ken McKee. He was demonstrating his hip to a group of American surgeons and one asked him how long did he think these hips would last. This, remember was only about 8-10 years after he'd started using them! McKee looked up at the ceiling for a bit then said, "Well I suppose if we get ten years out of them we'll be doing well"! He didn't know, you see - it was just a number he snatched out of the air!

    However I now have these articles in the Forum Library that speak for themselves!
    Hips that have lasted 32, 40, 41 and 45 years
    67½ year old - the THRs, not the patient!

    Not in the least! The design is intended to have less wear. In fact, a LOT less wear!
     
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  10. dlp

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    I played around with the sample Stryker ADM X3 my surgeon had in the exam room. All of the extra motion ability it has spreads the wear out across multiple surfaces. There's still the concern of the polyurethane inside the metal acetabular cup, but the ceramic ball it uses will always be a LOT smoother than any metal, meaning less scratching/scraping/wear of that inner part of the implant.
     
  11. Andy P

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    Hi Josephine, I think I just have a general anxiety about their lack of transparency. I've had a few surgeons lie to me and now I'm really suspicious about whether I'm in the right direction.

    I've seen 4 surgeons so far and each one tries to get you to agree to a lateral approach, meaning a 28cm rectangle being cut out of the side muscle then sown back. This approach is know for causing poor gait. Yet when I've challenged this, and say I'll go somewhere else, then they offer a minimally evasive surgery that has half the recovery time.

    So once I've been through this I'm not able to trust the next thing they say as it seems very unprofessional to offer the worse approach first.

    I woke up feeling that this is some sort of death sentence, not in absolute terms, but whatever compromise they decide on, I have to live with.
     
  12. Andy P

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    Hi Josephine, I was attempting to send you a pm, but don't quite know how to work the forum tools.
     
  13. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    @Andy P New members can't use personal messaging until they have more than 5 posts. But you've got 5 now so you can use them! Just as a starter, I've sent you a PM!

    I've also moved your discussion into a new thread here in the Pre-op Forum. This is because Adam W, who started this thread, has had his surgery and so the rest of this thread will be moved into the Recovery Forum. As a result of this, you are now the Thread Starter and your posts are also a different colour to everyone else's.

    So how are you doing with your research?
     
  14. Andy P

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    Hi @Josephine, thank you for helping out, I should know these things.

    Well, I haven't gotten very far at all. I'm certain of the benefits of dual mobility implants and the wear 'risks' I feels aren't relevant. Basing my thoughts on this:

    Relatively smaller bearings wear less quickly and have less chance to cam or stripe within the liner. So the smaller bearing should wear the same as the regular poly-ceramic. Then the larger mobile bearing moves a lot less and only with extreme movements, so unless one is a dancer etc, then its unlikely to have any significant wear.

    But the general biomechanics issue is unsolved. Trying to get my head around what a smaller bearing in the DM (around 28mm) will do to affect the gait dynamics. Or, should I try and push my surgeon towards the maximum size traditional bearing (36mm+)

    My concern is that I already have a worn knee and an irregular gait will speed the need for more surgery. So far, none of the surgeons I've spoken to are very open to questions. And If I do get to ask them anything then the answers are too snappy and general, sometimes inaccurate.

    In particular, one repeating issue is that the surgeon will first suggest a lateral approach and a CoC inplant, this they say is their best advice. Then when I go back and say I don't like the idea of a 28cm opening in the side on my leg, why not use a posterior approach, then they suddenly change their minds. I don't understand. It's as though their first advice is bad until you push them for a better option, the you get a more considered approach.

    Thing is, when to stop pushing and to know that the advice is good. I'm really struggling with some of the lies I've been told
     
  15. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    Andy, they'd not lies. They're just different opinions. You have to understand that no surgeon is wedded to a particular device or approach. During the span of their career they used many different types of each and at the stage when you see them, they have pretty much chosen which they feel gives them the best results "in their hands". This last phrase of important because what works well for one surgeon may not work so well for another - each being a different individual of course!
    Honey, you're trying to re-invent the wheel! All this stuff you've mentioned has already been researched and tested out to the Nth degree and in regular use for years. So surgeons who do a significant number of them per year will be aware of the variable. That's how come they make the choices (of device or approach) they do. This plus the buddy system (mentioned below) ensures that all of what they suggest in terms of devices and approaches are exactly what they say is so.

    One other point, if they have a patient who comes back and says no, they don't want this that's been recommended, they have enough experience to offer an alternative. So right now you have to listen to that they say and take is as read that they will be recommending this because they have had best results with it. After all, what surgeon in their right mind would recommend a device/approach they didn't get good results with!

    But don't forget, in any decent sized hospital, they will have a fairly significant group of fellow surgeons they meet with on a regular basis (often daily) and discuss problem issues on an almost daily basis. I've sat in on a number of these meetings over the years and can tell you that they don't pull their punches with one another! If they think one of their colleagues is being a prat in his approach or ideas, they will say so in no uncertain terms! This is the benefit of what we call "the buddy system" where each surgeon is closely monitored by his colleagues. In light of this, I think you can rest assured that most of what you've been told will stand up to scrutiny.
     
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  16. Andy P

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    @Josephine I do appreciate what you say. There is something very odd though. The initial recommendation of a Lateral approach is wrong, and I don't understand why the patient has to tell them this. A posterior approach reduces pain and speeds up recovery, even NICE are not sure why surgeons are staying with the Lateral approach is it doesn't benefit the patient.

    I can see that the Lateral approach has shorter theatre time, but to not make this aware to the patient is not honest.

    With my current surgeon, I gave him exactly the same information on the second consultation, I told him I cycle a lot, sometimes 70 miles + on a weekend, I explained the risk of falls is high, if not inevitable. The first advice he gave me for a CoC implant is very poor as the ceramic liner can crack. His view was that it would just mean a revision if I had an accident. Meaning, a revision is highly likely, therefore, I wouldn't risk it. But when pushed again, with the same info, he suggested a poly/ceramic DM. I asked for a posterior approach and he said yes.

    So, I dont understand. I've been attacked by the surgeons for 'googling' and if I dont I'm stick with a implant that wouldn't be best choice for me.
     
    Last edited: Jul 13, 2018
  17. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    It's not wrong, it's just a matter of opinion and no approach has more pain and slower recovery than any other. The myths that abound about this are numerous and incorrect. Just as numerous as the number of different approaches!
     
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  18. Andy P

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    Sorry @Josephine, this is different from everything I've read. The posterior approach is minimally invasive and much of the muscle can be pulled aside, there's still trauma but less actual cutting. The lateral approach requires a 20-28cm rectangle being cut through the side of the leg. The fascia band is then scarred and often does not heal fully and as a result is the main cause of limps after hip surgery; I have a relative that still has pain in that area after 20yrs.

    My guess is that as one method is quicker, the risk of infection goes down and surgeons op for this over recovery benefits for the patient. Overall outcomes are comparable. So i can see their point, but I dont like that its all hidden and options are not discussed.

    My experience so far is that every surgeon has done his best to avoid discussions about approach or implant, one at UCLH even refused to tell me. To me this does feel like an attempt to conceal the patients options and is unfair.
     
  19. Gidget

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    I don’t think there’s any conspiracy to prevent patients from having input. It’s just that there are so many variables. Dr experience at certain approaches, outcome trends on their patients, funding by insurers/hospitals, patient anatomy, patient preferences, patient compliance, outpatient supports, home environment, patient exercise tolerance, patients occupation etc etc.

    No one thing fits every bodies circumstance and don’t forget your doctor is allowed to have a preference for their technique as well.
     
  20. Josephine

    Josephine FORUM ADMIN, NURSE DIRECTOR Administrator

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    I think I see where we are at odds. We are talking about two different posterior approaches. The one I am talking about is the standard posterior which has been done since the late 1880s. What you are talking about is the new Micro-Posterior Hip Approach which certainly is all that you describe.

    But the lateral approach was generally considered the lesser of the two traditional posterior and lateral approach. I haven't yet fathomed if you are talking about a different one to me but I know many people, friends and relatives as well as patients, who had the lateral approach and did pretty well with it.
     

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