Become an Insider

THR Dual mobility acetabular cup vs traditional implant #1

Adam,
I am considering having a THR with Dr. S and probably want a dual-mobility system like you have. How is it going? Do you feel any pain? Do you feel like the unit ever feels like it's going to pull out? Any squeaking?
Any suggestions?

Thank you,

Doug (from Sarasota)
 
I'm delighted with the prosthesis and with Dr. Stolarski's work. Please give him my regards.

I have never felt any pain. The unit has never felt as though it's going to pull out. No squeaking, and I don't think it's likely with the ceramic on plastic mechanism.

My podiatrist noted that I have an unusual gait, but it predates my surgery. She made me an orthotic to help correct the problem and suggested physical therapy so as to reduce the strain on the implant and help it last longer.

The only time I can tell I have a prosthetic hip is during certain Pilates exercises. They're not painful, but it does feel different than the other side does.

I skied about 60 days last season without incident. I have five days in so far this season.

The main concern surgeons seem to have with the dual mobility acetabular cup is the lack of long-term data. There's nothing you or I can do about that except wait and see! I am an optimist. If there are problems in 15 or 20 years I'm hoping future technology will allow it to be replaced with something even better.

Good luck!
 
Thank you very much. I'm already feeling better after hearing from you! I very much appreciate your response!!!
Thank you! I'll definitely send your regards... -doug
 
Hi @doug7
Just tagging on as I also have Biomet Dual Articulation. Funny as I also reached out to @Adam W prior to my surgery. I'm 4 months post op and am pretty much back to normal activities (except running). No pain, no feeling like it will pull out (one theoretical advantage of dual mobility is an increased range of motion) except for muscles that haven't been used for a while...
I've seen different comments where some OS recommend dual mobility for younger patients (better ROM) whereas others don't (due to potential increased wear from a third articulation).
I believe one of the registries has started tracking dual mobility but long term data isn't available...
As Adam says, only time will tell...
D
 
Thank you both very much.

It seems that issues with poly on ceramic were significant enough to redesign the poly cup (breakdown of improved with next gen poly and additives (like vitamin e) and this breakdown causing biological changes and reactions. Ceramic on ceramic probably has less long term data on it than poly but it certainly appears that despite the lack of biological reactions to the material, it is seems to be more prone to cracking, stripe wear, and of course squeaking (although there are cases to warrant that this only happens when the implant is not installed correctly.
https://www.medscape.com/viewarticle/845651

Intuitively, it seems that poly would provide more potential cushion and impact distribution and potentially minimize cracking, but it might be at the cost of wearing and remolding and wear debris-which is a concern for EITHER method in my opinion. So maybe the cup can be thought of as a consumable, replaced every 10-15 years with the benefit of reduced dislocation risk, better ROM, and much better results for active people. So every 10 it's pulled out, the acetablar implant and ceramic ball is cleaned out, and a new cup goes in-and then off for another 100,000 miles. :)

One lingering concern here then is whether next gen cup materials are easy enough to swap out (vs replacing with what was already there). It seems like once those metal parts are installed and mate with the bone, they stay in and pulling them away from the hip bone especially could be a disaster, so if the next gen poly doesn't hold up or causes osteolysis, could a ceramic on ceramic or something not yet available be put in without implant revision.

I'm going to ask Dr. S about this because I can't imagine a new material could be placed in the same acetabular implant, but it seems like the ceramic on poly could be quite effective for at least 10 years, so 3-4 more cup replacement surgeries wouldn't be the end of the world provided there was no reaction/osteolysis or major issues with the metal implants.

Did either of you receive the short-stem (which is often suggested for younger active people to preserve bone and allow for future revisions?
 
Hi @doug7

A lot of questions - I'll be interested to hear how your OS replies...

I believe it is possible to replace the poly liner. It seems unlikely you can change liner materials (poly to ceramic) unless the current acetabular cup installed already supports either a ceramic or poly liner...

Regarding cup revisions, I hope it will be as easy as you make it sound but that also seems unlikely... :)

The wear data for current generations of poly is just now starting to reach the 12-15 year mark in the registries. It will be worth watching what types of revisions are done going forward.

My understanding with the previous generation was that the wear debris (over .1mm/year) caused the osteolysis and loosening of either the cup or femoral stem...

Regarding my implant, I believe it is standard length uncemented ceramic on Vit E enhanced poly...

D
 
dapplega said:
I believe it is possible to replace the poly liner. It seems unlikely you can change liner materials (poly to ceramic) unless the current acetabular cup installed already supports either a ceramic or poly liner...
Click to expand...
That can be done assuming the liner is the only problem. But if the shell is firmly secured, there's no excuse to touch it.
dapplega said:
Regarding cup revisions, I hope it will be as easy as you make it sound but that also seems unlikely... :)
Click to expand...
Most revisions are pretty much like the primary in terms of recovery. It's only when there are complications like infection that it can become a bit of a nightmare.
dapplega said:
The wear data for current generations of poly is just now starting to reach the 12-15 year mark in the registries. It will be worth watching what types of revisions are done going forward.
Click to expand...
The data only shows the median in statistics. Only this evening I was walking to an old friend who reported that a mutual friend had just died at 96. She was one of the first hip replacements we did at my hospital back in 1975 so her hip lasted 42 years and she was buried with it! There are other similar reports
Hips that have lasted 32, 40, 41 and 45 years
67½ year old - the THRs, not the patient!
dapplega said:
My understanding with the previous generation was that the wear debris (over 0.1mm/year) caused the osteolysis and loosening of either the cup or femoral stem...
Click to expand...
That's why they started making plastic cups impregnated with Vit E - it reduces the wear ratio!
 
I understand that wear with dual mobility is not the only issue. The device has a metal encasing that is installed up against the metal acetabular liner. This constitutes a metal on metal articulation (not talking about the ball and socket which is often ceramic on poly). Some reports show elevated metal ion levels as this is a metal on metal articulation. My surgeon told me about this and several journal articles corroborate. Still it's a great option for me- I need a revision for instability. I'm hoping someone on the forum with dual mobility will have their metal ions measured and report back. Thanks!
 
@gingko - I am confident the dual mobility I have, and all that I have seen, do not have any metal/metal articulation. The acetabular cup is titanium, the liner is ultra high weight cross linked vitamin E infused poly, and the ball is ceramic. Metal/metal is an issue but not that I've seen with dual mobility. Can you send a link or a pic of what you are referencing?
 
gingko said:
I understand that wear with dual mobility is not the only issue. The device has a metal encasing that is installed up against the metal acetabular liner. This constitutes a metal on metal articulation (not talking about the ball and socket which is often ceramic on poly). Some reports show elevated metal ion levels as this is a metal on metal articulation. My surgeon told me about this and several journal articles corroborate. Still it's a great option for me- I need a revision for instability. I'm hoping someone on the forum with dual mobility will have their metal ions measured and report back. Thanks!
Click to expand...

If I'm reading your description correctly, I ran across this implant when researching, and it seems to possibly match your description:
broken link removed: https://www.coringroup.com/assets/product-resources/dual-mobility/Resources-Product-Information-Trinity-Dual-Mobility-Surgical-Technique.pdf

However, I don't think there is any MoM articulation. The acetabular cup does have a metal liner, but that does not articulate - it's seated firmly in place and the poly head moves within that liner, and then metal or ceramic ball is used inside the poly.
At least for this model, it states "The liner is correctly seated when there are no further movements of the liner within the shell."

If you have data on other models that do have MoM articulation, I'd be curious to see and compare them! I never ran across any of those.
 
Hi, It is hard to understand why there might be metal ions since there is no movement between the metal shell and the metal liner, yet studies show, through a process of corrosion, a small amount of ions can be released. Here is one article:https://www.arthroplastyjournal.org/article/S0883-5403(15)00649-X/pdf. And here is another:
https://www.ncbi.nlm.nih.gov/pubmed/28057394
I'm wondering if one can have a dual mobility device placed with only one shell/liner molded together. I think it is called a monoblock and the SERF company may make one. Have you had your metal levels checked? How do you like your dual mobility otherwise? My hip is subluxing and I'd like to get a revision with dual mobility once these ion questions are addressed.
 
Yes, the Stryker ADM X3 is a monoblock acetabular cup, with poly liner and ceramic femoral head. It's a great implant, but I'm a little biased :)
 
I'm a few months from my 3 year mark.
Glad to see all is well.
Thanks for the update :dancy:
 
What a nice update!
Your thread will help others in their replacement journeys.
Happy (ski) trails!
 
You must log in or register to reply here.
Active Antimicrobial Hydrogel

Staff online

Members online

Total: 949 (members: 5, guests: 944)

Latest posts

Back
Top Bottom