Looking at our database, we looked at 3,000 contemporary, primary total hips from 2006 to 2017. We identified 2 cases; this is 2.5% of our revisions, and a tenth of our primaries done during this period. We also went back and looked at our most recent 350 revisions from 2015 to 2017 and we added one additional case so this is 1% of the revisions we’re doing.
So, in conclusion, cost is a local issue, clearly ceramic heads cost more. Mechanically assisted crevice corrosion is poorly understood at this time. I believe it is a rare problem—certainly in my area—and I have to work with my hospital every day. Mechanically assisted crevice corrosion that leads to an adverse local tissue reaction has absolutely no effect on my hospital cost or my 90-day cost since I was in a bundle, but ceramic heads definitely increase the cost per patient for both of these.
Moderator Thornhill: Okay so let’s just take a couple things where there’s some differences in the interview. Andy, Rob said that a ceramic head is cost effective even if it’s for $486 or less. Can you take this to your hospital and get them to agree?
Dr. Engh: I think all of us have been wanting to take 10- and 15-year data to our hospital and at this point, and for as long as I’ve been in practice, hospitals are not concerned about 10 or 15 years. Patients move they go other places. It’s orthopedists that are concerned about them, the hospital just sees their cost per patient. It’s extended from their hospital stay now that we have bundles out to 90 days, but I don’t see it going past 90 days.
Moderator Thornhill:Rob, what did we do to the trunnion or the assembly that has led to this problem or did we just not have a clue that this existed?
Dr. Trousdale:We have no idea how important the surgical factors are, the design issues, but we do know cobalt chrome is a common thread. Now the cost thing is interesting, there is no question, up front, it’s a lot cheaper to use cobalt chrome heads in most hospitals. A lot of centers are getting the ceramic and cobalt chrome for the same price but up front it is more expensive, certainly down the line.
Moderator Thornhill:Andy would you prefer a ceramic head or a cobalt chrome head? You showed it both in cobalt chrome on cobalt chrome and on titanium. Some people feel that there are certain types of implants that have a predilection for trunnionosis. I don’t want to name implants, but would you prefer or be more likely to use a ceramic head on somebody with a titanium stem than a cobalt chrome stem?
Dr. Engh:My indications for using a cobalt chrome head or a ceramic head are really age related. My younger patients are getting a ceramic head. I’ve switched to titanium stems. My center’s been using chrome cobalt stems for decades, I’ve gone over to titanium stems now, so it doesn’t make a difference to me.
