---
title: 'Pre-operative Planning'
type: 'lesson'
url: 'https://doc.social/courses/robotic-total-hip-arthroplasty/pre-operative-planning'
course: 'Robotic Total Hip Arthroplasty'
course_url: 'https://doc.social/courses/robotic-total-hip-arthroplasty'
position: '2 of 4'
author: 'Cory Calendine, MD'
transcript: 'yes'
---

# Pre-operative Planning

## Summary

_This lesson is a recording without a written summary._

## Transcript

3,249 words · 16 min · 2 speakers · automatically transcribed (aws-transcribe) and not checked by a person; it may contain errors, particularly in names, drugs and dosages. The recording is the source.

[0:00] Speaker 1: Again, the, the, the 3 steps, guys, is what we're talking about. So the preoperative planning, I think is what we're gonna see first. So it's the CT scan first and then Bob, off you go.
[0:09] Speaker 2: Yeah, so let me see if I can pause it here because there we go.
[0:14] Speaker 2: Yeah. So it's a little delayed, so I'm gonna try to pause it. But I think it's paused, it still moves. Um, so what we're gonna look at is, uh, this patient, you know, we're gonna get a lot of screenshots, but try to keep it really simple. This patient, we're gonna do the right Hip, had a CAT scan 2 or 3 weeks before the Surgery. This is the model you get back. So you get what's called the segmented model and this is the model we get back.
[0:38] Speaker 2: As I was doing these, and I'm still doing them, Corey, I, I capture screenshots to kind of create a file on every patient. So some of these screenshots are educational, but every patient has a, a file on them to see exactly what the heck I did. So here it is. And what you can do with the new 4.0 is you can look at leg length.
[0:57] Speaker 2: By the issue. Um, 3.0 used to go to the anterior siac Spine. This, you have the option of going to is issue.
[1:05] Speaker 2: Uh, so that's the model we start with.
[1:08] Speaker 2: Uh, that's what you'll get on the day of the OR, about 1 week, 2 weeks before. The mouse that's rolling around was the time of the Surgery, so what we're kinda showing you is what you get preoperatively, you know, total Hip was done 12 years ago, and you can see versus the opposite side, the current Hip is a little shorter and a little decreased in the offset.
[1:29] Speaker 2: Um,
[1:30] Speaker 2: So I have to just bear with the mouse because I can't speed it up.
[1:36] Speaker 2: There we go. Yeah,
[1:37] Speaker 1: and this is the view that I typically look at. So this isn't an X-ray, but this is, you know, Mako's simulation to look like an X-ray because it's what we're used to looking at,
[1:44] Speaker 2: right? So, what I, what I do here, I, I keep the screenshot of the, the plan, and then I keep the screenshot of what an X-ray would look like. So this is all from the CAT scan. It's recreated, uh, to make it look like an X-ray, which is kind of where most guys want to start.
[1:59] Speaker 2: And then we'll go into templating.
[2:01] Speaker 2: A template in sequence.
[2:04] Speaker 2: is all along this column here and we'll kind of go through it. I go to the cup first. I tend to look at this, um, view, and we'll pause it here for a second. I can do it.
[2:16] Speaker 2: No, OK, I barely got it in time, but the cup, the initial plan on the cup, 43 of inclination.
[2:25] Speaker 2: Uh, cup version supine in 17. So it's just kind of ballpark where we put it. I hadn't played around with it at all. This is what I got from Stryker. Then what we're gonna look at is what we talked about lumbosacral motion and sacral slope. I'm gonna hit play again, try to get rid of the cup. There we go.
[2:44] Speaker 2: And so this is all new for me and I don't pretend to be an expert. These are X-rays from the office, a seated X-ray, a standing X-ray.
[2:53] Speaker 2: Uh, there are ways to measure pelvic tilt, which I find really challenging. It's just
[2:59] Speaker 2: It's, it's the x-rays from the office, but there's a point up here and there's a point maybe down here.
[3:05] Speaker 2: I have a much easier time finding the sacrum. Um, so we have a seated 14 degree and standing goes up to 30 degrees. So it, it has some flexibility and I guess you can categorize these as hyperflexible, stiff, flexible. There's all kinds of categories. I haven't categorized patients. I just kind of
[3:24] Speaker 2: Uh, plug in the numbers. So we go to the program.
[3:28] Speaker 2: Standing sacral slope. Uh, we plug it in right here. 34.
[3:34] Speaker 2: And then we'll hit sitting sacral slope.
[3:39] Speaker 2: And this, this may seem, may seem onerous, but it only takes about 3 or 4 minutes to do.
[3:45] Speaker 2: So what we're getting, so I can pause it, there we go. So then we're gonna get a cup that's in 4317.
[3:54] Speaker 2: Plan supine. Here's the relationship to standing. Here's the relationship to sitting. Uh, so now, we'll use that in a little bit to look at our dynamic model, but I'll continue to plan the cup and um,
[4:08] Speaker 2: And this is where you come in with the 3D planning.
[4:11] Speaker 2: We'll go up and click on the cup.
[4:14] Speaker 1: Well, and, and this is a really good point, Bob, this may be some of the first time people are, are seeing or maybe thinking about those numbers changing, you know, just, just to be clear, you know what the sacral step, uh, what, what the sacral slope is showing is that pelvic mobility, so essentially this pelvis is rolling back or adding an aversion to the cup when they sit versus when they stand. And so again in three dimensional space you can see that's what 13 degrees difference in an aversion.
[4:42] Speaker 1: When they sit. This, this may be the first time, just so much information there. Maybe the first time some people are thinking about it like that, but normally we're just planning on a standing film or, uh, even, even before with Mika, we were planning when they were in the CT scanner, so supine, but we don't have that restriction now because of the mobility.
[5:01] Speaker 2: Yeah, that, that's a good point. Sorry, Corey. No, so this is kind of where I start and the analogy I start with is when I used to template two dimension, I always started with the cup. So here I start with the cup. Um.
[5:12] Speaker 2: Up here on the top left, we look at transverse and I just kind of start.
[5:17] Speaker 2: In the beginning, put the cup, what I call anatomic, tuck it underneath the front.
[5:21] Speaker 2: And this is a size 54 over to the right, you can change sizes and everything else.
[5:27] Speaker 2: So obviously bone is magenta, prosthesis is green, center rotation of the cup is green, center of the nato femoral head is magenta. Just gives you an idea of what the heck we're looking at.
[5:37] Speaker 1: And are you worried about moving that Hip center, Bob, or you're just, you know, as long as we get our length and
[5:42] Speaker 1: so
[5:42] Speaker 2: I, I, yes, so I will. I'll look at this and I'll kind of file it away. And if I were to increase the cup size.
[5:51] Speaker 2: Uh, let's pause this if I'm gonna do that. If I increase the cup size, I can lateralize the cup, but I'll, I'll start with this, and as I go through the steps, I may come back and change the cup as you see, as we go through this. But this is just my starting point. So this is the first screenshot. Then right over here, you're actually going to get a view. I call it the ring view or striker calls it the ring view. Let's see if we have it. You'll actually see.
[6:16] Speaker 2: I think.
[6:18] Speaker 2: Do I have the mouse?
[6:22] Speaker 2: There we go. You should be able to see.
[6:25] Speaker 2: The re view in one second. So what I'm showing here is just what I call the anatomic kind of laid in there. It's somewhat medial. We may have lateralize it a little bit to, so we don't lose this offset, but in the first step, we just kind of drop it in where we would think anatomic cup would be.
[6:40] Speaker 1: Yeah, as that's, as that is coming up, you know, planning a cup in three dimensions is a little bit weird on a CT scan, but, you know, you, you, you've done, you've done this a lot. But yeah, it's so easy just to move the cup out away from that medial wall. That's kind of where I like it off the wall, um,
[6:57] Speaker 2: and that's, that's kind of what we're doing what you asked. We kind of moved it a little lateral, so it's kind of off the wall. Here's the ring view. So what, what does this mean? And I hit pause.
[7:06] Speaker 2: Ream view is basically what you're gonna see when, before you ream, all that green is gonna be reamed. So these are all uncemented cups. So that's a fairly significant surface area and you can see, I think in the old days, we all tried to medialize the cups and take it down to the medial wall. Well, here, we're not doing that. So if you do that, you crush their offset. Um, so we, we tend to look at our offset, look at how much bone, uh, there'll be with the prosthesis. That's the ream view.
[7:33] Speaker 1: Yeah, and, and I've used Mako for a while, and I've found exactly that. When I get my X-ray the way I like, uh, I'm never reamed all the way to that medial wall, and like you say, if you do, you may have trouble catching up with your offset. So yeah, anyway, all that's clean.
[7:48] Speaker 2: So then I, then I go to the stem just like we're doing two dimensionally. So here, go over to the right, this is a 5 stem.
[7:54] Speaker 2: Uh, and again, stem is blue, no surprise. The center of rotation is blue on the stem. You can change your, uh, neck size. This is a 0. And again, here's your center of head, femoral, cup, and stem.
[8:10] Speaker 2: So we, we started with a 5. Let's see how we end up.
[8:17] Speaker 2: And again, the mouse is kind of pointing it all out. It's kind of really tight, but I think we got it in.
[8:24] Speaker 2: And one of the things I'll show you real quick, if I can pause it, there it is. So in the enhanced, there's your osteotomy plan right there, that green line. It's kind of low.
[8:35] Speaker 2: If you look over here, now you're gonna get a little data where you put the cup.
[8:39] Speaker 2: And if you keep the stem in that position, you're gonna be 4 millimeters longer than you were pre-op.
[8:45] Speaker 2: And you've increased your offset by 2 millimeters. These are millimeters. We're, we're really looking to the millimeters when we put in the Hip.
[8:52] Speaker 1: Yeah, I,
[8:53] Speaker 1: I love, I love arguing about that, but it does tell you the opposite side too. That's where, yeah,
[8:57] Speaker 2: and compared to the upside, uh, it's 0-0, so it looks like a pretty good starting point.
[9:03] Speaker 2: I'll start it up again.
[9:10] Speaker 2: And I think we dropped it to a 4, yeah.
[9:16] Speaker 2: And we actually
[9:18] Speaker 2: May move the floor up a little bit. That osteotomy looks kinda low, so we can change it and dial it in with the enhanced, we'll actually be able to draw this osteotomy on the bone.
[9:27] Speaker 2: And if I can draw a straight line, I should be able to cut it, but I'll show you in this case, it was, my line was off a little bit, but we'll get to the end and I'll show you that. So what we're trying to do is not crush the offset.
[9:39] Speaker 2: Make it a little bit longer, but still I can go over here and drop it to -2 and still be OK.
[9:45] Speaker 2: So now we're going to look at versions. So one of the new features of the 4.0, I'm gonna pause this for a minute again.
[9:52] Speaker 2: Is 3.0 head femoral version. So thermover is center of femoral head to the medial epicondyles, and your femoral version is 8 degrees.
[10:00] Speaker 2: I haven't played with the stem. They, this came from Stryker, and they just dropped the stem in and they said, oh, it stem's 23 degrees. So now a 4.0, we can actually plan broach version, and we're going to show you that in one second. I'll get this thing started again.
[10:14] Speaker 1: Well, it looks like you're using a stem accolade 2, I think is what that is. And so there is some flexibility there as far as where the stem goes in.
[10:22] Speaker 2: There is, and, and what happens is, here we go. So this is your brooch view.
[10:28] Speaker 2: And this is set up for an anterior, but what I do is I start over here on the left side and you look at transverse and you just kinda look at how the brooch goes down the neck. So this, yeah, so I'd say it's 23 degrees, but if you put that anatomic, you're gonna dial this 23 back closer to what is normal. So,
[10:46] Speaker 2: What we do is go up and start rotating the stem, which kind of looks anatomic, and we'll see what the stem version we're going to be shooting for.
[10:56] Speaker 2: So we basically go transverse sagittal.
[10:59] Speaker 2: So what we're doing is we're dialing the stem and if you click here and you look over here you can see we're dialing that stem version back.
[11:06] Speaker 2: To get what I think is more where the stem's going to go and maybe more anatomic.
[11:12] Speaker 1: Yeah, and the 3D model really shows that it looks like in the initial position, you know, the stem would have, you know, broken out the cow car if you will, so you're really just kind of turning it into where you think it's gonna land,
[11:24] Speaker 2: right, yeah.
[11:26] Speaker 2: And then the coronal.
[11:27] Speaker 2: So now we've got the stem, we got the brooch version or stem version 17, and then I rotate that view cause that's the view we're gonna look at in the OR. So if I get this view in the OR.
[11:42] Speaker 2: That looks just like this, I should be able to guesstimate that my stem version is around 17 degrees if I elect not to do the enhanced.
[11:51] Speaker 2: Um, yeah,
[11:52] Speaker 1: and, and, and just, and just to put a point on that, you know, we're, we're gonna show you enhanced, it, it has two different arrays, but you still have access to this visual if you decide not to put that femoral array on. So like you're saying, you can still pull this up intraoperatively and, you know, get an idea of your
[12:09] Speaker 1: femoral version.
[12:10] Speaker 2: Absolutely, yeah. So this is the dynamic model. So you go back, everything's put together, and this is where we're planning 4 longer, 0.
[12:19] Speaker 2: Uh, a little longer than the Other side and a little loss of offset compared to the Other side. But now, we're gonna look at the cup and dynamic modeling or the virtual range of motion. So we're gonna click here.
[12:30] Speaker 2: And what it's going to allow us to do is in the lower we can move the model any way we want.
[12:37] Speaker 2: And in the lower corner here we're gonna start doing external rotation.
[12:42] Speaker 2: And it's gonna show, I think we removed the femur, but you'll actually see red where you're gonna get an impingement.
[12:49] Speaker 2: Um, and there's a way you can remove the femur.
[12:52] Speaker 2: And so you can actually see.
[12:55] Speaker 2: Uh, it might be getting a little bit of red there and removed it. Still no red at all, so no impingement, there you go, 55 degrees of external, uh, with 5 degrees of extension. So that's really not anything significant. But then again, that's a dynamic model. So you can look at it extension as if you're walking externally rotated, and then the Other one we're gonna look at is sitting.
[13:15] Speaker 2: And we're going to force internal rotation.
[13:19] Speaker 2: Um, and we'll see where it impinges. Now, you'll have osteophytes up here and you'll it'll show you if you get osteophyte impingement. Most of those osteophytes you're gonna remove.
[13:28] Speaker 2: That one you're not gonna remove.
[13:30] Speaker 2: Yeah, I'd probably leave that. I'll probably leave that one alone, um, but see, you don't have any impingement. And then the final one is you do call it hyperflexion, um, or flex as far as you go, and you get the same amount. You get the idea of how much impingement you get. So we bring it back down to zero and then hyperflex it up.
[13:47] Speaker 1: Yeah, and, and, and, and I don't wanna break the symposium based on this, but you know, what, you know, what is there a number target you're looking at in particular, or, you know, I, I, these numbers might be different, right, if you were anterior versus posterior Approach, that kind of thing, different considerations. Yeah,
[14:03] Speaker 2: so what I, I'm gonna pause it for one second. What I don't know is what's the proper.
[14:07] Speaker 2: Per number, right, because everyone's different. So this person gets to 140 degrees, but they had a big BMI and a big stomach, they're never going to see 140. Their stomach's gonna impinge before any implant's going to impinge. So I, I don't really know, but I kind of look and I, I don't like seeing early impingement, and if I do see early impingement, I want to decrease it. I just go over here, dial some inclination.
[14:31] Speaker 2: Think about my version.
[14:33] Speaker 2: Or maybe even go over here, you know, change from a 127 to 132, or if I'm at 132, go to 127 and if I change this over here, I'm gonna get immediate results on what's going to change here as well as my impingement model. So this, this is a working screen, um, and it.
[14:53] Speaker 2: I know as we're going, we're going through really slow, people must think this takes forever. It, it takes about 3 minutes,
[14:59] Speaker 1: yeah, and, and,
[15:00] Speaker 1: and, and you do this just at the time of Surgery now, right, Bob? I mean, when, when I started Mako Hip, in fairness, I'd have them bring it to me a week before or something and play with it. But, but, you know, you, you, you've gotten comfortable if you're just doing this like as you're walking into the theater, yeah,
[15:13] Speaker 2: yeah, I mean, uh, your, your MPSs are unbelievable. So if there's a really, we've had a couple of them today, really complex, challenging Hip, um.
[15:22] Speaker 2: They'll come to you beforehand. Otherwise, I just do them in the morning and I do the same thing here. And what we showed you there was we played around with neck length and its effect on leg length and offset, but you can then run the, the, the model again. Um, yeah, so I, I just do it the morning of. If there's some crazy, uh, dysplasia or something which we have tomorrow, we looked at tomorrow's today just to make sure that we
[15:44] Speaker 2: We're, we're comfortable with what we gonna do,
[15:46] Speaker 1: and I, I think that's a really good point that that term, I think we throw that around sometimes we forget some people may not know what that is, you know, the Mako product specialists, they're like the guy in the room and like they're looking at all these plans. You keep saying Stryker brought me the plan, uh, you know, those MPS guys are really the ones kind of delivering it to you,
[16:04] Speaker 2: um, yeah, they're,
[16:06] Speaker 1: I don't know. I haven't met him yet,
[16:07] Speaker 2: but I think they're, I think they're like the wizards in the Wizard of Oz. They, they run the computer and

## In this course

- [Previous: Introduction to Robotic Total Hip Arthroplasty](https://doc.social/llms/courses/robotic-total-hip-arthroplasty/introduction-to-robotic-total-hip-arthroplasty.md)
- [Next: Intra-operative Overview](https://doc.social/llms/courses/robotic-total-hip-arthroplasty/intra-operative-overview.md)
- [All lessons: Robotic Total Hip Arthroplasty](https://doc.social/llms/courses/robotic-total-hip-arthroplasty.md)