Moderator Berry: We’ve all just heard 2 excellent talks on 2 different ways to handle one of the toughest problems in revision hip replacement, which is pelvic discontinuity. One thing I’d like to emphasize to everyone in the audience is that while both of the techniques are quite different, they still emphasize a similar concept.
They both are trying to turn the hemipelvis into a unit and get a stable socket without necessarily trying to get this chronic nonunion to heal itself across the nonunion.
Both of the speakers emphasized that and it’s worth pointing out that a third technique that you didn’t hear about this morning, which Wayne Paprosky has popularized where you actually kind of distract the pelvis, put in a big cup and allow the elastic recoil of the sides of the pelvis to squeeze the cup in and hold it together; and hold it against the pelvis also does the same thing. It creates a unit out of the hemipelvis but doesn’t require healing of this bone that’s so hard to be to heal.
Now let me turn to the debate for the moment. Allan, Keith made a valuable point which is if you’re willing to play with lots of little pieces and put them together and enjoy the jigsaw puzzle element of things, you can make a cup cage work. But on the other hand, it does take a certain element of 3-dimensional thinking and familiarity with all the pieces and figuring out…and patience, if you will…kind of reconstruct it in surgery.
What do you think about the idea of dropping in a big thing that somebody’s already done on the back table? Pros and cons of that. You want to give us that from your standpoint? Why haven’t you gone to that?
Dr. Gross: For one thing, I think that we actually do a custom device, but we do it intra-operatively. And we have trials for all of the different cups, cages and augments. So, we put the thing together with trials, intra-operatively, as opposed to some engineers doing it based on a 3D reconstruction. The other thing is that occasionally a triflange cup can be delivered and it’s too large or too small.
We don’t have those problems. I agree that there are certain advantages to a triflange cup. For us, even though a cup cage is expensive, a triflange cup is much more expensive and you have that long waiting period. The other thing about a cup cage is that sometimes you get surprises in the operating room. The bone loss is bigger than you expected radiographically. You find a pelvic discontinuity when you didn’t expect one and we can address that on the spot. We didn’t have to order in a custom device.
Moderator Berry: One of the problems with a triflange is it’s a great big device and requires a lot of exposure to get in. Occasionally they go bad. If they go bad, of course, it’s a big problem. You reported 22% complication rate in your triflanges and only a small proportion of those were pelvic discontinuity patients. And the pelvic discontinuities are a much tougher subset than the whole group that you reported on. So, we can assume that in the pelvic discontinuity group your complication rate would be at least that high.
Tell us, how do you go about trying to minimize the risk of big complications if you’re putting in a big implant like that?
Dr. Berend: I think that exposure-wise the model is very helpful in knowing where I’m going to need to be putting my parts and my screws and what I need to get exposed. In having the model to me ahead of time allows me to customize my approach. Am I going to do a trochanteric osteotomy?A trochanteric slide? Do I need to take the femur out? Do I need to do something more complex to get that exposure?
At the end of the day where we’re putting the fixation, where we’re putting the part…it is a big part to put in, but it’s not any bigger than putting together a large cup cage custom with an augment, let’s say. You’re seeing the same stuff.
Great, two legends of the game. Do we have an audiovisual format for this debate?