Moderator Thornhill: Do you agree that the squeakingin a ceramic-on-ceramic has decreased or you don’t think it has?
Dr. MacDonald:Well, there was one particular design that did have an issue, which isn’t even sold anymore so the rate overall has come down, but it’s not minimal. I think what we’ve done is a bit of a disservice where we say patients are okay with it and they cope with it, but they don’t like it.
Dr. Walter:You showed a video of a squeaking hip but there was also a clunk there. Sounds like neck-to-rim impingement and subluxation, and that’s not good for any bearing. If you use good surgical technique and good implants, our squeaking rate is 2% which is not insignificant but they’re almost completely benign.
Dr. MacDonald:Yeah, and I don’t disagree. I’m sure your squeaking rate is lower than many, and you’ve got a generation of experience with ceramic-on-ceramic but it’s more when we are all using it in all of our hands, doing our hips the way we do, it’s not as low as 2%.
Moderator Thornhill: Bill, you have a lower squeaking rate and obviously you are looking carefully at this. Is it technically harder to do a ceramic-on-ceramic than a ceramic-on-highly crosslinked polyethylene?
Dr. Walter:I think if you do a well-balanced hip with components that are positioned well, both bearings will function well. If you malposition your component, if the tension is not right, you’ll find out about it in the ceramic in the form of noise, so you’ll have impingement, you’ll have clunking, you’ll have squeaking. If you malposition a ceramic-on-crosslinked polyethylene bearing, you may get a dislocation, you may get a rim fracture, it may take a bit longer, but it will be a different kind of complication.
Dr. MacDonald:The question is then, ‘Is the ceramic-on-ceramic a bit more at risk with outlie?’ It probably is, like a metal-on-metal was, if you get edge loading. Your point is exactly right, you’ll see it sooner, it’s not good for highly crosslinked polyethylene either it’s just that could be a 10-12-year outcome as opposed to a 2-3-year outcome.
The other thing to understand is the nuance of putting in a ceramic, a modular ceramic insert, is that when cups are placed they sometimes deform in very hard bone, and you will sometimes see this when you go to put that liner in, it’s got an equatorial pivot point that you just do not see in a crosslinked polyethylene liner. So, be aware of that, because that’s when you get mal-seating and chipping.
Moderator Thornhill: Alright great job and thank you all for this nice debate.
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My friend who is 54 just had a hip replacement via a robot. He was so happy, he had another one done in 6 months. He can not recommend enough of ceramic hip replacement surgery.
Teri Green
Atlas Biomechanics