Moderator Thornhill: Let me get that—just a yes or no answer from both of you—Doug, do you believe that dual mobility is the first choice for the high-risk primary and recurrent dislocator?
Dr. Padgett: No.
Dr. Garvin: Yes.
Moderator Thornhill: Okay, good. Whew. You guys would both agree that not all dual mobilities are the same.
Dr. Garvin: Yes.
Dr. Padgett: Correct.
Moderator Thornhill: If you look at things like a constrained liner doing an anterior hip, doing a big head—36mm or 40mm—and the concerns associated with trunnionosis with that or even doing a resurfacing with a thinner poly, how would you rate those options?
Dr. Padgett: So, I think the evidence is quite in favor of using the largest diameter head that you can use, commensurate with the size of the socket you’ve put in. I’m in favor of using that with high-risk individuals, whether or not they’re high risk because their hypermobile or the patient who has the stiff spine. I think we can actually get better information to determine what the optimized position of that component should be both on the femur and on the cup. I think that you should avoid using this as your primary resource. I would, in fact, be in favor—of using an acetabular component that has a dual mobility option should, in fact, the need eventually arise. Because there are other issues that provide stability.
Moderator Thornhill: Same question to you, how do you rate the other sort of things—constrained, big head…
Dr. Garvin: I think both approaches, when done well and the components are in good position, I think are going to have that 1-2% risk of dislocate. I think it’s an important factor. Surgical technique is a very important factor to minimize your risk of dislocation.
Moderator Thornhill: We’ve talked about trunnionosis and stuff in a big head like a 40mm head. You’ll use a 40mm head, because I don’t anymore.
Dr. Garvin: I rarely use a 40. My standard would be a 36.
Moderator Thornhill: What’s your standard?
Dr. Padgett: Standard—I think—is 36 which is the new 32, which used to be the old 28.
Moderator Thornhill: You guys have said most everything. If you’re using a big head, let’s say you’re using a 40mm head, how thick poly do you want?
Dr. Garvin: I’m still a 4mm. I like to see 4mm of thickness, roughly. That 40mm is going to put you up in the high 50’s, probably a 60mm cup, so that’s why usually I’ll use a 36.
Moderator Thornhill: If you are going to use a dual mobility, do you think there is an added advantage to using an anterior approach?
Dr. Garvin: No.
Moderator Thornhill: Because it’s harder to do or just it isn’t necessary?
Dr. Garvin: I think the anterior approach is not without a risk of dislocation.
Moderator Thornhill: Very good discussion. I think this is something that’s on the rise in the United States and I think it’s going to be a while before we really know. Thank you both very much.
Please visit www.CCJR.com to register for the 2020 CCJR Spring Meeting — May 17-20, in Las Vegas.
