What would be your go-to to extract that?

Yeah, that's a great question because the most popular stems now are in the U.S. are these tri-taper compaction.

They really fill the metaphysis and many of them have very large collars.

So to try to get an osteotome around them is very difficult.

You'll hear people speak about cutting the collar off.

I could tell you that's a disaster, very hard to do.

And these are typically fully HA coated and they behave like a fully coated stem.

Your go-to method for removing a well-fixed hemispherical cut.

What will be the tipping point in that decision-making?

Yeah, so I think if the defects are routine and you don't have a lot of bone loss, you don't have a discontinuity or something where you may need additional fixation like a cage, add half a cage or drill your own holes or whatever you may need to try to get out of the OR with a stable construct.

If it's routine, I'm going to use a regular locking mechanism, porous cup.

If I'm using the shell as more of a defect management tool, many of these cups will go in quite vertical and neutral version because you're just filling a hole and trying to connect the ileum to the issue.

I don't really care the position of the cup, but I need a solid defect management tool with screws wherever I can get it, and then I'll change the face of my cemented liner.

So if I can get it with a routine cup, great.

Locking mechanism's easy, it's quick, solves the problem.

dual mobility when I've got abductor damage, but the lateral stabilizers are intact, no abductors, that'll be a constrained liner.

I'd love to hear your ideas on that a little bit more.

Yeah, the impetus for this paper was basically a few decades of frustration with how high the rate of failure was of constrained liners.

And so we wanted to put a pure series of acetabular revisions only, no femoral revisions, same surgeon, same indications, and we didn't accept any malpositioned cups.

So it's very enticing to see a cup in good position, say an 80-year-old woman, she's dislocating, muscle looks okay, the cup looks reasonable, let's just snap in a constrained liner and see what happens.

We know what happens, half of those fail in less than four years.

So we're trying to figure out what's going wrong here because many companies tout the ability to convert the constrained liner with a locking mechanism in a cup that's well positioned.

That strategy fails at a very high rate.

I think there's still a role for due mobilities.