AHF Podcast
AHF Podcast
Part II: Decoding Hip Resurfacing with Professor Justin Cobb
In this episode of the AHF Podcast, host Joe Schwab continues his in-depth conversation with Professor Justin Cobb, focusing on the specifics of performing hip resurfacing with the H1 ceramic on ceramic implant through an anterior approach. Professor Cobb provides a detailed walkthrough of the setup, techniques, and tools required for the procedure, highlighting the importance of complete capsulotomy and the differences from standard hip replacement surgeries. He also shares his insights on femoral head measurements, the role of fluoroscopy, and advice for dealing with challenging cases. Tune in to learn the nuances of hip resurfacing from a leading expert in the field.
Hello everyone and welcome to the AHF podcast. I'm your host, Joe Schwab. This week we have part two of our conversation with Professor Justin Cobb on hip resurfacing. We focus our conversation more on specifically how he performs hip resurfacing with the H1 ceramic on ceramic implant through an anterior approach. Let's rejoin the conversation. I wanna switch gears a little bit and talk a little bit more about the practicality of doing one of these hip resurfacings specifically from an anterior approach. Um, because, you know, as a concept, we talked about this a little bit. Uh, some people find that anterior approach, uh, is, uh, maybe more difficult for doing a resurfacing, I think for various reasons. Um, but the first question I have for you is, can you walk me through a little bit of the usual equipment that you use, uh, for one of these anterior approach hippers surfacings, things like table fluoroscopy, any special devices, and especially anything that might differ from a setup of a standard anterior total hip replacement.
Justin Cobb:So for a, um, an ordinary person, nothing different at all from a standard anterior tunnel lip. I mean, the wonderful thing that job matter, I mean, I, I, I definitely, as I said at the beginning, I don't feel I've invented anything here. There are giants before me in Joel. Obviously a huge, huge figure. And in Europe there are several, obviously, huge figures who've, who've done anterior total hip. And Indeed and Paul Budha would actually call out, um, in the, in that, um, and in Europe, um, Heinz Barer was doing anterior resurfacings in the seventies. Um, so it's not as if there's anything new there. All the only, the only difference, the only difference is the amount of capsular release. And if you watch, uh, Fred Load doing a, uh, anterior total hip, um, the capsule is briefly in size in a tiny way, because he's an amazingly conservative surgeon, we have to do a complete release of the capsule. And the, the big difference between resurging replacement is we're trying to keep the femoral head and neck alive. And the reason that I, the, one of, one of the reasons I think the anterior approach is attractive is that if we, we do an ellipsoid. Capsulotomy. So we take the capsule off superiorly and laterally right round to the mid coronal plane before dislocation. We'll obviously take the whole of the pubal femoral off medially. And then having dislocated, we then do the posterior capsulotomy, well away from the femur joining up, cutting across the whole of the she femoral ligament. And if you just, you, this is an intracapsular, um, procedure once you've dislocated, but we've completely released the capsule, then the femur femoral head goes approximately laterally. Um, and it, it's honestly not difficult. So, so the release, it's just a complete capsulotomy. And of course that's not as good as an incomplete capsulotomy, but I don't think you can do a resurfacing from the anterior approach without a complete capsulotomy. And so we just not, we do that.
Joseph M. Schwab:But you have an anterior based capsulectomy first and then an inside out. No capsulectomy not You said nothing. You, the ellipsoid is not a capsulectomy. It was,
Justin Cobb:No, no. We go the, the, just to describe in words and, and we'll put some pictures to it. The anterior radial along the lines, right? Just beside IOC Capis.
Joseph M. Schwab:Yeah.
Justin Cobb:I tried to leave cap, iron cap towers on the capsule there. We don't, we don't disturb that. Just right from, from the, the labrum at the top right down to the instructionary line. And then at the top of that, we go round beneath the indirect head of rectus, right round to the Midal plane. And in fact, and then actually with a pair of scissors, um, push and take out the lateral bit of the iseo femoral ligament from the front there. And, um, um. A fellow gild in Atlanta describes that very nicely. And Ben do, I think lots of people do. Everyone, everyone has to do that. Um, George Gild in Atlanta, um, describes that nicely. And then, then you take the whole of the pub femoral ligament off right down to the lesser trant.
Joseph M. Schwab:Okay.
Justin Cobb:And then, then having taken that all off, you put a lever over the TAL, which gives you access to the sort of inferior head and neck junction. And quite often there's a sort of frenulum of capsule of so onto the femoral head and neck junction there, which you take off. And having released all of that with Ilio Captima, you can then put a sharp home and your sharp lever onto the pubis and lift up. And you have a lovely view right from the, uh, super end of the TAL. Right round the front of the caps, right around the front of the rim and do your rim surgery now, because forever after, it's gonna be harder than now. So we do the rim surgery before dislocating then. Um, and, and so do all your anterior, um, head preparation at that stage. And then if, if it's a slim woman, you don't need a table. Um, we just, if a labor, if a ligamentum is intact, either a ligamentum cutter or just a curved, um, Bovie just to release the, um, um, uh, and then the hip, there's no force involved. It's a very, you don't have to use force to dislocate the hip.
Joseph M. Schwab:Yeah. And, and you can see that, so basically at this point, with the acetabulum exposed, the way you described, or with the, with the joint exposed, the way you described, you can quite easily see that notch that you're so, you know, careful to
Justin Cobb:So in a, in a bloke,
Joseph M. Schwab:Yeah,
Justin Cobb:in a big bloke, it doesn't matter. They've got masses of bone. You can bury a socket in a big man, it just doesn't matter. In a slim, in a sorry width person in a woman, um, they haven't got a huge acid pelvic bone there. And that, that, um, uh, notch, uh, ile pubic recess there really makes sense when you, when you put the trial prosthesis against it.
Joseph M. Schwab:And
Justin Cobb:Um.
Joseph M. Schwab:so. you're, you, you do your rim surgery, you, you clean your rim at this point, and then you move towards the femur before you do true acetabular
Justin Cobb:then so, so, no. Um, I think it is. Uh, so what, um, Derek, with, with the approach, what he said was, do your acetabular surgery first because you ought be as conservative as you can be. And so you don't wanna take masses of pelvis away. Um, you measure the, the, the head neck junction with tongs before you dislocate to confirm what sort of size you're in. Then I personally think you then go and do your acetabular surgery, put in your socket, bearing in mind what you know, you've gotta achieve your head, and then do the head surgery. If you are very concerned, you can do the head first. Um, and. I, I think for, for, uh, you can choose, I think there's some indication of doing one first. Some for the other first, as I think it's true with total hip arthroplasty actually is some people want to know their version on their femoral stem before they put their socket in. I've heard that that proposed.
Joseph M. Schwab:Um, so the, um, you know, the size of the prosthesis you're gonna be putting in as soon as you do that, the head, neck junction measurement before you've done any dislocation. Yeah,
Justin Cobb:I mean, from the x-ray, um, what, you know, have you got a cam, IE somebody with a fat neck and almost a cylindrical neck? Um, or have they, are they a aplastic here with a slender femoral neck and the, the, the slender neck, you've got three or four choices of femoral head that will all fit there. With a guy with a, um, short, very fat neck, you have got very limited choice. That's a very narrow fairway. You really can't, because particularly when the head is, um, inferior and posterior, that's, that's the really demanding hip. And there you haven't got much choice. But actually they are pretty much all, um, men who've distorted their femoral head by a lot of exercise in their teens. So they've got, they've got a lot of pelvic bone, so you can. You can upsize. So we, in the planning, we really pay greater deal attention there. But unless you're doing ct, you know, your 2D plan, it's always plus or minus the size. So you have to valid, you have to measure with the tongs, you know, what is the size I'm gonna go for here? Which is really, really what is the size of the head, neck junction? What is the, um, that's what you're really measuring there.
Joseph M. Schwab:Yeah. And the, if, if you are, maybe, if your measurement is slightly in between sizes, how do you deal with that?
Justin Cobb:Well, that's where I think it's, it's worth, um, that's where you go to acetabulum first. So you then say, is the, so some people occasionally see someone whose femoral head has really ground out the acetabulum and they have quite a big mismatch with a big socket. And there it's quite, you know, that's, that, that's the most difficult thing for a servicing, honestly, because. You can't really up, you know, you've got a limited relationship there. We haven't yet had a problem, but I can, I theoretically that could be a problem.
Joseph M. Schwab:The, because the cups and the head sizes are matched, right?
Justin Cobb:that's right, that's right. And truly I have, um, from the old days, the old hip resurfacings had two thicknesses of aceta for every femoral head because in the very old days, the, it wasn't, um, every two millimeters, it was every four millimeters of femoral head. So the first, I think from 2000 till 2004 or five, it went 46, 50, 54. Um,
Joseph M. Schwab:Wow.
Justin Cobb:So that's why there were two thicknesses of VAs tablum, because that was a big jump in feral head size.
Joseph M. Schwab:Yeah.
Justin Cobb:Um, but it, but I haven't used a thick acetabulum. I, I don't think, I can't think of any one for decades, so, so. You measure the feral head size, go to the ace tabular, and then choose, are you gonna go to the bigger or smaller?
Joseph M. Schwab:sure. And is trialing part of the procedure? Do you do trialing at all for either the femoral or acetabular side or, okay. I.
Justin Cobb:Um, both. Um, on the, on the ace tabular side, it's really about getting the, um, orientation of the, as of the acetabular component, right. Which is important in women, in men, it really isn't very important. They've got masses of bones, it doesn't matter so much, but in anyone who's got a bit of dysplasia, you really want to get that rotation. Absolutely right. Um, on the, on the acetabular side, and are, we've gone over to reusable instruments, so you have to know, because you don't really have control over your anymore, you have to know that your trial has got a pre fit. Um, and so the trial is, is a pre fit for orientation. In three ways. So abduction version and rotation of the acetabular component. And in fact, once you've set that on your impactor, then we don't change that rotation for the the acetabular component. We then, and I'll give you a little video clip showing that, um, just showing how that works.
Joseph M. Schwab:Um, and, and so, um, do you use fluoroscopy during the procedure as well? Do you use any imaging
Justin Cobb:I do, I don't actually, I do it before closing. Um, I don't do it before that, but I mean, just I, um. It is really interesting. I'm, I'm, I'm sure you know, there's the, the surgeon who's doing planned surgery where you are, if you've got a CT based plan, you feel that's the truth. I'm achieving my plan. If you've got, if you've got a 2D plan, you know it's a guide, but in the end, you've gotta make the decision because those x-rays aren't as accurate as you thought they were. So you really are making your mind up about size, but the angles are pretty much true from your, on the acetabulum, but on the femur, of course, not so much. I, I think if you are, if you are used to, and I know there's a whole group of people who have the Fluor on the whole time. Um, I, I, I don't, I think it's an interesting way of doing it, but it's slightly different from looking and feeling, and I'm, I'm still, I suppose I don't like doing more than a couple of flashes of radiation. I don't like wearing lead, so we tend to just do a flash at the end to make sure nothing's moved. Um, um, and obviously with cementless, acetabular components, things can move and so that's why we do it after. Really, that's risk time for me, I would say.
Joseph M. Schwab:that's, that's what you're checking for. But there would be nothing to prohibit you from doing it during the procedure if you needed to
Justin Cobb:No,
Joseph M. Schwab:uh, for position uhhuh. Okay. That's just a level of comfort.
Justin Cobb:And that's right. It's interesting, isn't it?
Joseph M. Schwab:yeah. Do you find, um, so first of all, do you have, um, a backup total hip set when you're doing this? Or do you, do you ever find that you have to bail to a total hip for one reason or another? Or has that not been an issue?
Justin Cobb:I, I can't remember the last time that happened. I mean, we have total upsets, um, in the background, but we don't say is one sterile? Um, because seems like that would be a very unusual day at the office. That'd be very unusual. I mean, you know, this, we're doing this operation on someone who's got a healthy femoral head and neck and the instruments. Um, and again, I'll, um, they we're very excited about our, I'll put, I'll send you a couple of video clips of, of the femoral neck guide. Um, the, the huge difference between resurfacing surgery and tu hip arthroplasty is that it's guidewire based. And if your guidewire's wrong, you can't correct it like a DHS If the, if the guidewire's in the wrong place, you can't correct it. And if you think, oh, I'll just correct it with the next instrument, then things go badly is you just have to change your mindset and accept all of your time is spent making sure that the position and orientation of your guidewire is right and the, the, the stylists and the jigs really help that. So it's easy to know. Be fine. And, and you just check, check, check. There are three checks on the femoral side, um, before you start machining bone
Joseph M. Schwab:For, for the position of the Guidewire to make sure it's
Justin Cobb:position, position, orientation.
Joseph M. Schwab:Okay. Um, and the, uh, any other, so you mentioned the, the device that's used to, to, uh, you know, position the guidewire for the femur. Any other special devices that are, that you use or that are needed are, again, are you doing this on a standard table, on an orthopedic table? What,
Justin Cobb:So, so I've done both. Um, and in fact, um, in a couple, in six weeks time, when you come over, we're gonna present a little bit of data on, on table and no table. Um, I think in, in, um, women, you just don't need a table if, but if you're used to it, it is, it's just as easy in a big man. I think a table is a really big help because it, um. Obviously you don't, unless you're using, um, Fred's w computer guided table with their numbers, you don't know the forces. You are, you know, that finishing the external rotation on the boot, um, you don't know the forces. You have a good idea, but it's, it's, it's unmeasured. But in a big muscly man, um, the table makes it much easier. And,
Joseph M. Schwab:Okay.
Justin Cobb:and right now, I'll say for any woman, I would absolutely say, uh, anterior approach is less trauma than a posterior approach. But for huge blokes and, and of course the female pelvis, the, the, the hip is at the front of the pelvis, whereas in men, it's really in the middle. And for those guys with huge thighs, it's literally in the middle. And there's no benefit of anterior or posterior for those people. Really, there isn't. Um, and for those guys, either way, you need big levers. Because you are in the middle of a big person. Um, that, and that we all know, I mean, anyone who does resurfacing knows that huge athletes are, are, you know, they're pretty challenging.
Joseph M. Schwab:And that, so how many, uh, um, assistants are you using, uh, during your case? How many people would be, would you need to have scrubbed in apart from yourself?
Justin Cobb:Um, I definitely have one person scrubs in either a gas store or a gule, depending on, um, how many I, you smile at that there, you, you need, you need some something or someone on the other side of the table as well. Um, I think, I think just, um, uh, Chris Corins beautiful bits of string, they're not quite enough for, for that. I mean, Paul Bulley has, has, um, a different device, but you need some something. The far side of the table just for the feal head prep really.
Joseph M. Schwab:Yeah. And when you're, uh, when you're evaluating the position of your components, for instance, it seems like there's, um, maybe naturally is, uh, perhaps the right word, perhaps not naturally less concern about, um, what their length and offset is because of the relatively small amount of bone you're taking away. Is that the philosophy?
Justin Cobb:So the length is a really big deal in, in men because men with cams have usually worn their hip out by having a great time and they've got really hard bone. And so if you are not, and when you are resurfacing a cam on the femoral side, you are taking the rugby ball and putting a football on the end of the femur, um, and lengthen by three or four millimeters on a.
Joseph M. Schwab:Yeah.
Justin Cobb:Ream acetabulum out superiorly. You can distalize the acetabulum too. So, so it is possible to lengthen someone by five or six millimeters by mistake, lengthen. And so you have to pay attention in those cams. Um, but the offset and the offsets, the thing that I think the total people really just don't agree with because they spend a lot of time getting the offset exactly right. But we frequently reduce the offset by a centimeter frequently, uh, or even 12 or 30 millimeters because you are wanting to put, you are doing top of neck based surgery, you're putting the femoral head back on the top of the neck and that rugby ball shaped femoral head has got a whole lot of bone beneath the compressive rabbe. That's very osteoporotic. You don't wanna resurface that. So you are, you are really lateralizing the femoral head. Putting it, getting a load through the compressive directly, again, frequently changing the offset very substantially. And, and suddenly Andy Murray, there are lots of, you know, alpha level athletes who've had very substantial offset reduction and are none the worst for it. So the rules seem to be quite different for resurfacing replacement in that respect,
Joseph M. Schwab:So you re um, offset is not something you, it sounds like you worry about too much, but with
Justin Cobb:horizontal.
Joseph M. Schwab:Yeah. Um, as far as length, how do you evaluate for, uh, leg length during the procedure if you're, if you're waiting and doing fluoroscopy at the end, is that when you find out or do you do checks during
Justin Cobb:So, um, if I'm doing, if I'm doing male table based resurfacing, then. Um, I, I don't pay very much. I mean, because we planned what we're doing and your measure, your, your napkin ring, which, which is your top head cut, which of course isn't, it's giving you half offset and half leg lengths. But in a cam you, it's mainly medial. There's often very little or no bone. You're taking away laterally with that, um, napkin ring. You get a, you know, with that what you're doing on the femoral side and uh, on the acetabular side, you are getting your acetabulum in at the right depth or orientation. We are not spending any time worrying about changing the leg length very much at all. Really
Joseph M. Schwab:Okay. Okay. So really not too many checks for that, it sounds like. Interesting. Um, and do you do, do you ever do any leg length films afterwards? If somebody, what? What would be a typical complaint that you might see for somebody who has a leg length issue? Or is it just not common
Justin Cobb:Well, you can see it on the plane X-ray. I mean, if, if, if you've done it, you don't need a leg film to tell you that, um, you better start apologizing. Um,
Joseph M. Schwab:So humility. That's the approach.
Justin Cobb:yeah, well, surgery keeps you humble, Jerry. You know, it keeps you pretty.
Joseph M. Schwab:this is true. This is true. Um, so I, I appreciate you walking me through some of these questions. Uh, one, one additional question from a surgical standpoint, if you were to need to do additional release, um, to mobilize the femur, you feel like you've done your full cap. Uh, you, you've done your capsulotomy the way you described, uh, where normally you would expect to have a mobile femur, you've double checked to make sure that that capsulotomy is as complete as it is normally, but you're just not getting that mobility and it's obstructing your view of the acetabulum say, or your ability to put the head somewhere safe. Yeah. What do you do?
Justin Cobb:so Gregor, first of all, in that stiff, short necked, um, man who's a real headache, whatever, I would definitely take out, take down the top 15 or even 20 millimeters of TFL off the bone, um, and would definitely repair it afterwards, but I would straightaway do that.
Joseph M. Schwab:Okay.
Justin Cobb:Um, not, not even think about not doing it in such a person because that lets the TFL sit down. So you, you see well beyond the Midal plane before you dislocate and that, so, and you've made a nice, you can push a big swab down into that. Um, freeing the, uh, DT eye off the lateral capsule, making sure that's all, all free there in such a person. And then, and I've definitely had this experience and it's because there's still fibers of the issue of femoral ligament you haven't released, or it's the pube femoral you haven't released. Um, and you know, when you've completely released the pube femoral ligament because there's room for your fingers there, there's no tension there anymore. So if that is released, it's almost certainly you haven't fully released the she of femoral ligament. Um, because the muscles aren't the problem, it's the capsule. Um, I think that's a, I'd be really interested to hear what, um, um, so Paul has done thousands of anterior hip sings. I'd be, I'd be interested to know what he says about that. My experience, which is hundreds or thousands, is that, um, it's about the capsule. Whichever approach you use for resurfacing, it's about the capsule.
Joseph M. Schwab:Yeah.
Justin Cobb:Um, because that's the uncompliant thing. The muscles are just so much more compliant
Joseph M. Schwab:Yeah.
Justin Cobb:and we don't, we don't, the T ffl releases the only muscle release if you do, if you, if you have to.
Joseph M. Schwab:Do you release that soft tissue or do you take a sliver of bone with it? How do you do your TFL release?
Justin Cobb:I just, I just do, so I mean the very top, front edge of TFL is quite tenderness and if you just take it off sharply there you have a nice bit of tenderness material to sew straight back on. So I haven't taken a piece of bone off myself. Um, um, but I think there are lots of ways of doing that.
Joseph M. Schwab:Yeah. So, um, uh, obviously you're looking forward to the H1 being released to a broader audience of surgeons, which is, uh, uh, it sounds like a lot of years of development have gone into that and a lot of experience. Um, what do you think is next for it? I mean, is this gonna solve hip resurfacing or do we have more problems yet to yet to
Justin Cobb:I. think I. I, I, obviously it's not the only, um, new resurfacing device out on the blocks. There's the resurface, which is already inducing in Australia, and the poly motion. So these are three novel resurfacing without the bronze of metal and metal. The problem is not the devices,
Joseph M. Schwab:Yeah.
Justin Cobb:it's, it's a surgeon. And, um, getting people's skills up is, is so we are, I'm literally spending the whole time right now trying to get the technique, the steps as crystallized as possible. And it feels like, um, right now the steps are the steps. And if you, if you do complete each step, and of course you think you, you may not have completed, you think you debut in completely completed. That's often a thing, isn't it, in surgery, but it feels like, um, getting people. To learn how to do it and, and deliver it. That's, it's, no you saying this is really cool, but nobody else can do it. That's not interesting, is it? Um,
Joseph M. Schwab:It's hard for it to catch on if that's the case. Yeah,
Justin Cobb:Yeah, yeah, yeah, yeah. But I think the, for a total, for a total hip surgeon who's doing is very happy with their arti total hips and is regularly doing that. They know if you're doing a Hemi arthroplasty, then you're much more conservative on the capsule side. If you're just doing a hemi arthroplasty, if you're doing a, a total hip, you are not as conservative as for Hemi Arthroplasty. If you're doing a, if you, if it's, it's perfectly easy to start preparing Cebul without cutting off the head, neck for hip. It's perfectly easy to do that, and you do that. I don't think 97 year olds should have hip resurfacings.
Joseph M. Schwab:Okay.
Justin Cobb:I think that's probably too old.
Joseph M. Schwab:Yeah.
Justin Cobb:96. I'm not too sure.
Joseph M. Schwab:You have to have a limit somewhere. Right. Well, professor Cobb, I really appreciate you meeting with us. I, I, uh, absolutely, uh, adored our conversation and I appreciate the way you approach, um, how you think about hip surgery, how you think about trying to conserve around the hip and, and how you think about trying to deliver the best for your patients. I really appreciate having you.
Justin Cobb:So it's been great, a great honor. See you soon.
Joseph M. Schwab:Thank you for joining me for this episode of the AHF podcast. We think of the AHF as a family, so if you can remember to take a moment to like and subscribe. You'd be helping us find more people just like you to share our thoughts with. And as an AHF family member, you can always drop an idea for a topic or any feedback you like in the comments below, you can find the AHF podcast on Apple Podcasts, Spotify, or in any of your favorite podcast apps, as well as in video form on YouTube slash at anterior hip foundation, all one word. New episodes of the AHF podcast come out on Fridays. I'm your host, Joe Schwab, asking you to keep those hips happy, healthy, and maybe even resurfaced.
