There are things about technique-dependence…Michael showed on the tibial side…precision is needed for achieving perfect implant stability (Conlisk, et al., Knee, 2017).
And the question really: Are you all ready to abandon the cement? What about the patella? Is this the age of the unresurfaced patella among us? I think a lot of these things lack clinically relevant evidence and many fall under the same category as those proposed with PSI, which we’ve already gone through this exercise.
A lot of the appetite for cementless fixation also is commercial and economic, largely because total knee arthroplasties are now being performed in ambulatory surgery centers and there’s an appetite for speed and elimination of cement. But the evidence is that cementless fixation does not provide improved survivorship, improve patient outcomes, better reliability, nor is more cost effective.
So cementless total knee arthroplasty is not a game changer and cemented fixation is and will remain the gold standard for the foreseeable future.
Moderator Booth: Michael, those are some compelling numbers and the registry data is interesting. I don’t have the skill to do that little feathering that you showed Leo doing to get that prosthesis flat. How do you deal with it?
Dr. Meneghini: I think skill may not be the right word. Patience could be the right word. At the end of the day, registries are very valuable, but they lump data and the finer detail aspects can be lost. Registries also take time to show results. Some of the data is 2 decades old now. Some of the patients in the studies are 20-year follow-up studies that were published 10 years ago. That means those were implanted 30 years ago. The patients we see in our clinics now are very different from what we saw 30 years ago in terms of age, activity level and the demands on their protheses.
Moderator Booth: You supported doing it in women less than men. What’s the gender data?
Dr. Meneghini: It’s a bone quality issue. There’s no doubt that when women hit menopause their bone quality can decrease.
Moderator Booth: Age. You advocated most for the young. Why would we do less than the best in the young? A revision, for me, of a cemented tibia is easier than a cementless tibia.
Dr. Meneghini: That depends on the design. There are cementless tibias that are easier to revise, some that are less so. I think in terms of age…we approach it as physiologic age. In the Midwest you can have a 70-year-old farmer who is a heavy laborer and that person’s bone is as good as you’ll ever find in a 45-year-old female potentially. The one issue we’ve always seen in orthopedics—I’m sure you’ve experienced it—you do a reconstruction and you’re like, “Oh, this will do fine for 5 years. The patient probably won’t be alive by then anyway. It’s a tenuous situation.” And then they show up in your clinic 10 years later and you thought for sure, “Well, they surely won’t live that long.” But they do. Increasingly, a 70-year-old could easily have a 30-year life expectancy.
Moderator Booth: Gwo, people who make the decision to do a cementless knee want to preserve the cruciate, not resurface the patella, do a lot of things. Are those decisions additive, do you think, over time? Are they interrelated?
Dr. Lee: If you go down the path of abandoning cement, not resurfacing the patella would be the next logical step. I do think a lot of the impetus is commercial. Working in the outpatient setting, there’s an incentive to get rid of the cement. To Michael’s point about registries; the reason patients younger than age 65 have lower revision rates is the use of computer navigation, better alignment and better balancing. It has nothing to do with cement or no cement.
Moderator Booth: Thank you both for a good debate.
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