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Rethinking TFL Injury in Anterior Approach THA · AHF Podcast

• 0:21
  Joseph M. Schwab: Hello and welcome to the AHF Podcast.
• 0:24
  Joseph M. Schwab: I'm your host, Joe Schwab.
• 0:26
  Joseph M. Schwab: Anterior approach has earned its place in modern total hip arthroplasty with its fast recovery, early function, and a muscle sparing pathway that resonates with both surgeons and patients.
• 0:39
  Joseph M. Schwab: But as with many things in surgery, what we intend to spare isn't always what we actually spare.
• 0:46
  Joseph M. Schwab: One important, occasionally overlooked and often abused muscle and anterior approach, especially among surgeons in their learning curve, is the tensor fascia lata.
• 0:56
  Joseph M. Schwab: It's rarely the focus of our postoperative exams or outcome measures, and yet it sits directly in the line of fire during exposure, preparation, and implant placement.
• 1:08
  Joseph M. Schwab: At the 2025 AHF annual meeting, a poster from Columbia University caught a lot of attention, not because it was flashy, but because it was prospective and honest.
• 1:19
  Joseph M. Schwab: It asked a simple but important question, how often are we really injuring the TFL during anterior approach total hip?
• 1:28
  Joseph M. Schwab: When does that injury occur and what factors increase the risk?
• 1:33
  Joseph M. Schwab: today I'm joined by H.
• 1:34
  Joseph M. Schwab: John Cooper, who presented that award-winning work.
• 1:37
  Joseph M. Schwab: We'll talk about what they found, why most TFL injury appears to happen when we're not thinking about the TFL, and how these findings should influence the way we think about muscle sparing surgery.
• 1:51
  Joseph M. Schwab: So to help us rethink the TFL injury in anterior total hip, let's welcome to the show H.
• 1:57
  Joseph M. Schwab: John Cooper.
• 1:58
  Joseph M. Schwab: John, welcome to the AHF Podcast.
• 2:02
  Joseph M. Schwab: I.
• 2:02
  H. John Cooper: Hi.
• 2:03
  H. John Cooper: Glad to be here.
• 2:04
  Joseph M. Schwab: S You, were able to present this at our, 2025 AHF meeting in Nashville.
• 2:10
  Joseph M. Schwab: And can you tell me a little bit about why this was, a presentation that you decided to submit, for our call for submissions?
• 2:19
  H. John Cooper: this is a, project that, that, I've been thinking about for some time.
• 2:25
  H. John Cooper: Joe, and, it's something that is really important to me when I'm, doing surgery or when I'm teaching trainees to do surgery, is respecting the soft tissues.
• 2:37
  H. John Cooper: And, I certainly believe I do a much better job at this point in my practice than I did during my learning curve.
• 2:45
  H. John Cooper: And I, think we were curious about how often we were preserving the tensor completely, and when we weren't.
• 2:55
  H. John Cooper: Why, what were the, who were the patients at risk and what were the steps where it would be most likely to be injured?
• 3:02
  H. John Cooper: and I think that was the, reason that we wanted to do the study.
• 3:06
  H. John Cooper: And, a brilliant, student who was with me for two years, Caitlin Wolfel, pushed me to do this.
• 3:14
  H. John Cooper: And, luckily we had the resources to have somebody there.
• 3:18
  H. John Cooper: live during every surgery.
• 3:19
  H. John Cooper: That wasn't me that could focus on this and collect the data prospectively, which put us in a, good position to be able to do this kind of a study
• 3:27
  Joseph M. Schwab: we're super lucky that you were able to present it at the AHF and you have a presentation for us today.
• 3:32
  Joseph M. Schwab: Is that right?
• 3:33
  H. John Cooper: I do with some pictures and, our, thought process behind this.
• 3:37
  H. John Cooper: I'd be happy to share it.
• 3:40
  H. John Cooper: This is, a few slides about, what we intended to do, in the study and, what we found.
• 3:48
  H. John Cooper: And, we really wanted to look prospectively, consecutive, every single one of my total hips over a, three or four month period of time, where we were looking, specifically at the tensor during the case.
• 4:01
  H. John Cooper: That wasn't my focus during the case.
• 4:03
  H. John Cooper: I was doing the surgery like I always do.
• 4:05
  H. John Cooper: but I had somebody, an observer, looking at the tensor at every, at every case, at every step.
• 4:11
  H. John Cooper: I, have some disclosures, but certainly nothing relevant to the, to this case.
• 4:15
  H. John Cooper: So the, TFL as you, talk about in the introduction is, an often overlooked muscle.
• 4:22
  H. John Cooper: You can't overlook it when you're, going into the direct anterior hip that's right there.
• 4:25
  H. John Cooper: You have to find it to make sure you're in the right interval.
• 4:28
  H. John Cooper: but once we get around it, we tend to forget about it.
• 4:31
  H. John Cooper: And, I think anybody who's done an anterior hip, has noticed that sometimes at the end of the case, it doesn't look perfect.
• 4:39
  H. John Cooper: And it's often, in unintentionally maybe sacrificed or, injured, while we're trying to do a good job inside the, hip joints.
• 4:49
  H. John Cooper: and especially this is something, at least with me, that was more common during my learning curve.
• 4:55
  H. John Cooper: and I think, certainly became less with time and.
• 5:01
  H. John Cooper: So I think it remains a bit of a cause for concern.
• 5:03
  H. John Cooper: So our, purpose of this study was we wanted to prospectively look at, TFL damage during the consecutive set of anterior approach cases, with a mature, technique that was, really, had some steps specifically designed to preserve the TFL.
• 5:23
  H. John Cooper: So a few extra steps that I didn't do in the first five or 10 years of my practice, that I added to really try to make sure that tensor survived intact without injury.
• 5:35
  H. John Cooper: The vast majority of the time, goal is a hundred percent of the time, but as you'll see, that, that didn't happen even with these steps.
• 5:43
  H. John Cooper: so the, I'll, briefly, talk about the steps for, TFL preservation that I, think are important.
• 5:50
  H. John Cooper: and Joe, for some context, I am a hundred percent anterior surgeon.
• 5:54
  H. John Cooper: I don't select.
• 5:57
  H. John Cooper: specific cases, every, patient who's a candidate for a total hip gets an anterior hip with me.
• 6:03
  H. John Cooper: and, have been for, for 14 years now.
• 6:07
  H. John Cooper: so, the, six things that I think I incorporate into my practice that are specifically designed to, to preserve the TFL as much as possible, I think the most important, and I've got a video showing some of these steps is, how the, tensor is entered and, how the fascia is opened and managed during the case.
• 6:23
  H. John Cooper: I think this makes a tremendous difference.
• 6:27
  H. John Cooper: when you're making the saw cut and removing the head, specifically, keeping that tensor in mind because this is a common place for injury.
• 6:36
  H. John Cooper: something that at least in my hands, I think helps is utilizing offset reams and offset cup inserters that can glide over the tensor.
• 6:46
  H. John Cooper: The most common place that we, we, have found injury is, preparing the femur.
• 6:50
  H. John Cooper: So making sure before you start preparing the femur and implanting components that you've got number one, the right retractors that aren't gonna put the tensor at risk, but, that you're, most importantly, that you're doing the proper releases so that you've got adequate exposure, to, put your broach in, to put your stem in and you're not cranking retractors into the TFL, which is a really commonplace where it can get injured.
• 7:14
  H. John Cooper: We looked at a hundred consecutive cases, done between, toward the end of November of 24 and, beginning of March of 25, all comers.
• 7:23
  H. John Cooper: We weren't selecting, we excluded revisions, we excluded conversions, but all primary, total hip arthroplasties done by me.
• 7:31
  H. John Cooper: over a range of pathology.
• 7:34
  H. John Cooper: Were our study group.
• 7:36
  H. John Cooper: we looked at a lot of variables.
• 7:38
  H. John Cooper: We looked at all the patient demographics that you would expect in this kind of a study.
• 7:41
  H. John Cooper: We quantified how often the tensor was being damaged at all.
• 7:46
  H. John Cooper: and if so, the amount of damage, none minimal, less than 10%, moderate damage, 10 to 20% severe damage, greater than 20%.
• 7:55
  H. John Cooper: And, how did we do this?
• 7:57
  H. John Cooper: ideally we could have done this with, CT or MRI, to quantify, from preoperative to postoperative, any sort of, volume loss in the muscle.
• 8:05
  H. John Cooper: But we, we, didn't do that.
• 8:07
  H. John Cooper: we did it, in surgery.
• 8:09
  H. John Cooper: We were able to measure.
• 8:12
  H. John Cooper: with a ruler, the tensor ahead of time, and then at the end of the case, we'd inspect it and look for, fibers that had been injured both on the anterior surface, the medial surface, or, often the posterior surface of the tensor.
• 8:25
  H. John Cooper: And, with that same, flexible ruler, try to quantify as a percentage of the tensor volume.
• 8:32
  H. John Cooper: How much of it was injured?
• 8:34
  H. John Cooper: so admittedly there's a little subjectivity in that, but we were, Caitlyn kept me honest, and she would say, let me see the, other side of it.
• 8:42
  H. John Cooper: And, she was a hard grader.
• 8:46
  H. John Cooper: we also quantified when it was damaged, so we would inspect it, multiple, at multiple steps throughout the case.
• 8:52
  H. John Cooper: see is it still intact or was it damaged?
• 8:55
  H. John Cooper: and then in terms of the additional risk factors we looked for radiographic measurements, including the femoral neck shaft angle, the femoral neck length, and the width of the iliac wing relative to the IM canal, the femur.
• 9:10
  H. John Cooper: so whether the iliac wing was really overhanging, whether it was right in line with the femoral canal or whether it was a really narrow pelvis.
• 9:18
  H. John Cooper: and then a couple other things.
• 9:19
  H. John Cooper: We considered bikini versus longitudinal incision.
• 9:22
  H. John Cooper: I did both during this time.
• 9:24
  H. John Cooper: the majority were bikini, some were longitudinal.
• 9:26
  H. John Cooper: We wanted to see if that had any effects.
• 9:29
  H. John Cooper: Also form of fixation cemented versus cementless stems, again, which I was doing both, probably 15 or 20% cemented during this time.
• 9:37
  H. John Cooper: we, also wanted to look at clinical outcomes and whether the amount or prevalence or degree of tensor damage correlated with any three month postoperative, outcome measures, including the SF 12 and the WOMAC, which we, collected on all these patients.
• 9:56
  H. John Cooper: and I've got a video that shows, some of these steps.
• 9:59
  H. John Cooper: This is the video that we presented at AHF, in June of 25.
• 10:03
  H. John Cooper: I'm happy to go.
• 10:03
  H. John Cooper: through this or, and hopefully it'll show some of the, some of the techniques.
• 10:09
  H. John Cooper: But this is the bikini incision in a, patient with standard arthritis, of the hip here.
• 10:17
  H. John Cooper: I really wanted to highlight what I think is one of the most important steps in, in, in trying to preserve the tensor.
• 10:23
  H. John Cooper: Is really how you enter the tensor and how you manage the tensor.
• 10:27
  H. John Cooper: So through this bikini incision, I'm developing a plane just on top of the muscle.
• 10:31
  H. John Cooper: I'm looking at the tensor fascia.
• 10:32
  H. John Cooper: So the fascia overlying the muscle fibers right there.
• 10:35
  H. John Cooper: And my goal is to enter this fascial sheath as lateral or as posterior on that as possible, five or or six or seven millimeters, from the posterior edge of that.
• 10:46
  H. John Cooper: And what that does is that keeps most of the fascia medial.
• 10:50
  H. John Cooper: And when you keep most of the fascia medial, the tensor has more excursion laterally during the case.
• 10:55
  H. John Cooper: It's not tethered by the fascial sheath.
• 10:57
  H. John Cooper: And so it, it can move out of the way much easier, when it's not being tethered by an overlying fascia that keeps it, closer to the operative field.
• 11:06
  H. John Cooper: And I think this is really critical.
• 11:08
  H. John Cooper: And Joe, what you may have seen me do there, and I'll try to rewind this just for a second, is I'm really trying to open the, fascial sheath.
• 11:16
  H. John Cooper: Way proximal and way distal from what my knife, from where my knife goes.
• 11:21
  H. John Cooper: So with the, my finger, I'll bluntly dissect up and down because the greater the length of that fascial opening is the more excursion the tensor is gonna have, during, during the case.
• 11:32
  H. John Cooper: and that to me, I think is the biggest tip.
• 11:36
  H. John Cooper: that I've incorporated into my practice, over, over, 10 or 15 years is, giving that tensor just room, to move around without being tethered by fascia.
• 11:47
  H. John Cooper: and, that's made the biggest difference.
• 11:51
  H. John Cooper: step two is, one area where the tensor can be injured is, from the saw.
• 11:56
  H. John Cooper: You can see it's right there, right behind that retractor.
• 11:58
  H. John Cooper: And some patients are certainly more than others, but the side of the saw.
• 12:03
  H. John Cooper: can be injured, can injure the medial fibers of the tensor.
• 12:07
  H. John Cooper: You can see how close the saw blade is coming to the tensor right there.
• 12:10
  H. John Cooper: So abducting the leg a little bit, can help move the tensor away and just being really careful about that side of the saw.
• 12:18
  Joseph M. Schwab: Now I'm gonna have you pause for just a second because one of the questions that I have for you, and we've already gotten to the, part where we're removing the femoral head.
• 12:28
  Joseph M. Schwab: but te tell me a little bit about your capsular management.
• 12:31
  Joseph M. Schwab: Are you capsulotomy capsulectomy?
• 12:33
  Joseph M. Schwab: And if you do capsulotomy, do you tag the capsules?
• 12:37
  Joseph M. Schwab: tell me a little bit about that.
• 12:39
  H. John Cooper: It's a good, it's a really good question.
• 12:41
  H. John Cooper: I'm a, I'm a capsulotomy, surgeon, so I'll make an inverted t So the vertical limb, it's like an oblique vertical limb, directly paralleling the, middle of the femoral neck.
• 12:54
  H. John Cooper: And when I reach the distal insertion of the capsule, I'll go medially and later.
• 12:59
  H. John Cooper: I don't think this matters so much for preserving the tensor.
• 13:02
  H. John Cooper: It matters a tremendous amount for femoral exposure later.
• 13:07
  H. John Cooper: the medial limb for me is a variable release.
• 13:10
  H. John Cooper: I don't wanna over release in patients, who are quite flexible because I think this is an instability risk.
• 13:16
  H. John Cooper: But for stiffer patients, a bigger release medially is really helpful for exposing, that lateral release of the capsule, into the saddle and all the way back to the obturator externus is a huge part of femoral elevation and exposure.
• 13:31
  H. John Cooper: Later in the case.
• 13:31
  H. John Cooper: It doesn't matter for me so much right now.
• 13:34
  H. John Cooper: I try to get it all at, this stage on a capsulotomy, but certainly in stiffer, more muscular patients, it's harder to get that entire lateral superior capsule released all the way back to externus.
• 13:46
  H. John Cooper: But I wouldn't dream of trying to expose a femur without that capsule released from the saddle.
• 13:51
  H. John Cooper: because I think that, that, makes the femoral exposure so much harder,
• 13:54
  Joseph M. Schwab: And do you tag those capsular flaps with a suture or are they, is it just open and, you put, retractors underneath?
• 14:03
  H. John Cooper: Tag'em with a suture.
• 14:04
  H. John Cooper: and use them as retractors.
• 14:06
  H. John Cooper: it what I don't, or when one of my stitches, breaks off.
• 14:10
  H. John Cooper: What I find is that, that often those capsular flaps will become interposed between my trial head and the socket on, on, on trial, and just, a, a bit cumbersome.
• 14:21
  H. John Cooper: So having the capsular flaps tagged allows me to move them out of the way, almost like opening a set of doors, for somebody trying to walk through, when I'm doing reductions or dislocations.
• 14:32
  Joseph M. Schwab: And the reason I ask this is, my experience in teaching residents has been, it's a common resident issue and I've done it when I was in my learning curve where I would take that posterior capsule and the tagged portion of it and pull that, to, in order to, provide a sort of a retractor and pull posteriorly and it's, I used to call it to my, residents, I used to call it the cheese slicer effect.
• 15:00
  Joseph M. Schwab: It could sometimes just slide right through that tensor muscle.
• 15:03
  Joseph M. Schwab: And so I, was curious what you did with the capsule and whether that came into your, algorithm for tensor preservation or not, or maybe that's something you haven't experienced As much as I have.
• 15:14
  H. John Cooper: Absolutely.
• 15:15
  H. John Cooper: and you probably, hit on a very appropriate point that I didn't incorporate my algorithm just because I, I've had that experience years ago and learned not to do that.
• 15:25
  H. John Cooper: So I, rare, I rarely put tension on those sutures.
• 15:29
  H. John Cooper: really until I'm, until I'm trialing, way, later in the case, because I agree, those, sutures, they're thin, they're, and they can act just like a cheese slicer as you talked about.
• 15:40
  Joseph M. Schwab: Yeah, I,
• 15:41
  H. John Cooper: This is an area where I, have certainly myself entered the tensor many times.
• 15:50
  H. John Cooper: and, I don't do a napkin ring.
• 15:52
  H. John Cooper: I do a single cut.
• 15:53
  H. John Cooper: In most patients, unless they're really stiff and the head doesn't move at all, then napkin ring can be quite helpful.
• 15:58
  H. John Cooper: But for me it's a single cut.
• 16:01
  H. John Cooper: and try to flip that head up so I can, get a corkscrew into the head, to remove it.
• 16:07
  H. John Cooper: I think you're probably less likely to dance damage the tensor with a napkin ring cut.
• 16:11
  Joseph M. Schwab: While you, don't have the, as much, difficulty with the corkscrew, you do have multiple passes with the saw, which actually puts that potentially at risk.
• 16:20
  Joseph M. Schwab: I, so I, it's a good point and it's a good question.
• 16:23
  Joseph M. Schwab: I don't know.
• 16:24
  H. John Cooper: Exactly.
• 16:25
  H. John Cooper: I, think there, there's certainly, risks and benefits to both techniques a napkin ring or a, or a single cut.
• 16:32
  H. John Cooper: for most patients who aren't, severely contracted, a single cut works quite fine.
• 16:37
  H. John Cooper: For the patients who really have a, like a lot of productive arthritis and a lot of overhanging osteophytes where their head just doesn't move a lot, a napkin ring could be quite helpful, in, in, getting the head out.
• 16:46
  H. John Cooper: So I do a napkin ring probably 10% of the time, when that single neck cut doesn't let the head flip up like you're about to see here.
• 16:53
  H. John Cooper: So here the capsule's been opened.
• 16:57
  H. John Cooper: the head is flipping up and you're looking right at the cut surface of the femoral neck.
• 17:07
  H. John Cooper: this court where try to put right in the center position, like you go to cephalomedullary, screw in the nail.
• 17:13
  H. John Cooper: Right toward the apex.
• 17:15
  H. John Cooper: And, I, I try not to put this in until I get that good exposure of the cut surface of the neck.
• 17:21
  H. John Cooper: but this is critical at this point.
• 17:24
  H. John Cooper: What, do I do with this?
• 17:25
  H. John Cooper: So early on in my practice, I had a tendency to want to try to push this barrel of the corkscrew laterally or posteriorly, to try to lever the head out.
• 17:37
  H. John Cooper: And that is something that can really cut through the tensor.
• 17:39
  H. John Cooper: And I've injured, more tensors than I'd like to admit that way.
• 17:44
  H. John Cooper: So this, to me is something that you can never do, in my operating room, is try to bring that posterior.
• 17:51
  H. John Cooper: If you look at the fibers of the rectus anteriorly and the tensor posteriorly, that, those, that fiber direction, for me is the only plane that I think it's safe to move this barrel, in without injuring muscle.
• 18:07
  H. John Cooper: And you'll see me try to do that so proximally distally right in line with the fibers.
• 18:13
  H. John Cooper: And when you do that, after the head is spun, the head almost always pops off, pops out quite well, with that.
• 18:21
  H. John Cooper: And if you can do that, almost dislocating the head posteriorly, when you bring the barrel of that corkscrew up proximally toward the chest, and then bring the head right out.
• 18:34
  H. John Cooper: And that is something that's quite atraumatic for the tensor, and the rectus anteriorly.
• 18:45
  H. John Cooper: This is a bikini incision.
• 18:48
  H. John Cooper: and if I try to use straight reamers, or straight cup inserters, I'll find that, that they'll be pressing into the tensor quite a bit.
• 18:54
  H. John Cooper: So using an offset here.
• 18:56
  H. John Cooper: Now again, some surgeons I think are gonna have their own comfort level with this and their own different exposures, but I think using that offset, can be really, quite helpful in soft tissue preservation.
• 19:05
  H. John Cooper: It's a little bit of a different feel, but it's worked well for me.
• 19:09
  Joseph M. Schwab: It looks like you do quite a bit of acetabular preparation and implant placement, acetabular component placement, with no retractors in.
• 19:18
  Joseph M. Schwab: Is that correct?
• 19:20
  H. John Cooper: The anterior retractor is often something that with a limited medial release, makes the, entry of the reamer and the and the cup too tight.
• 19:32
  H. John Cooper: So taking that anterior retractor out at least is, something that can be quite helpful.
• 19:36
  H. John Cooper: I usually leave the posterior retractor in.
• 19:39
  H. John Cooper: Joe I think I took it out for that video just to show the tensor, but just show how we get around the tensor.
• 19:45
  H. John Cooper: But typically I'm leaving posterior retractor in.
• 19:48
  H. John Cooper: So the most common place that we injured the tensor was, on femoral exposure either during the exposure and elevation or, during broach entry.
• 19:58
  H. John Cooper: and I'm, not gonna go into detail about the femoral releases.
• 20:01
  H. John Cooper: we've, we published a few papers And video techniques on this, as have many other people.
• 20:07
  H. John Cooper: but, I think as, most people in the podcast, listening to the podcast will know this is one of the, more difficult steps in the learning curve is learning how to adequately expose the femur, and, get a good point of entry.
• 20:20
  H. John Cooper: and if you don't have that good access, I don't let a resident or a fellow, even me touch, a femoral broach until you have that access because you're just asking for trouble.
• 20:32
  Joseph M. Schwab: Let me ask you a little bit,'cause this part is really, crucial.
• 20:35
  Joseph M. Schwab: I think there's differences in.
• 20:38
  Joseph M. Schwab: Levels of femoral exposure between different styles of anterior approach.
• 20:42
  Joseph M. Schwab: So can you talk a little bit about your common setup?
• 20:45
  Joseph M. Schwab: Are you doing this on a standard table?
• 20:47
  Joseph M. Schwab: Are you doing it on an orthopedic table?
• 20:49
  Joseph M. Schwab: Are you doing it with any sort of additional equipment that allows for exposure or limb positioning?
• 20:57
  H. John Cooper: I'm doing this on a standard table.
• 21:00
  H. John Cooper: I keep the table.
• 21:03
  H. John Cooper: flat And, I extend the foot of the table about 20 or 25 degrees.
• 21:08
  H. John Cooper: So just a slight bit of hyperextension at the level of the hip joint to allow the leg to drop, into extension or hyperextension just a little bit.
• 21:18
  H. John Cooper: and that also allows me to, to ad duct and externally rotate the operative leg in a lazy figure-of-four position underneath the non-operative leg, which stays straight.
• 21:31
  H. John Cooper: So both legs for me are draped into the field.
• 21:34
  H. John Cooper: I don't have somebody or, an assistant on the operative leg providing tension.
• 21:39
  H. John Cooper: It just hangs where it needs to go.
• 21:42
  H. John Cooper: the vast majority of the time, every once in a while, one in 20 patients who's really stiff, an assistant to push that figure-of-four position a little bit harder, with the right releases, it just hangs there.
• 21:56
  H. John Cooper: it's a, very nice, exposure and the style of stem I think matters.
• 22:02
  H. John Cooper: So, most of the stems that I, I think many people are using now are.
• 22:06
  H. John Cooper: A slightly shorter, recessed shoulder, type stem, like a triple taper, a double taper stem.
• 22:15
  H. John Cooper: those can, be curved in a little bit easier than what I had started doing anterior approach with 14 years ago, which is a much longer, Corail type stem that needed a little bit more exposure.
• 22:26
  H. John Cooper: so we can get away with just a little bit less exposure than, and at least I needed, and in 20, in 2012.
• 22:33
  Joseph M. Schwab: And any sort of, femoral elevator underneath, either held by an assistant across the table or on your side, any bone hook, anything like that, holding the femur up.
• 22:42
  H. John Cooper: Yeah.
• 22:42
  H. John Cooper: So good, point.
• 22:45
  H. John Cooper: many of the orthopedic tables, that are designed for anterior approach have a femoral elevator built into them.
• 22:51
  H. John Cooper: The, what on the screen right now, that, on, the far right thing is a, standard bone hook, that I've put, in the same position as you would an orthopedic table hook.
• 23:03
  H. John Cooper: And I use that to elevate the femur anteriorly after the releases have been done.
• 23:09
  H. John Cooper: I used to use, I think for eight or nine years, a table mounted hook that would stay in that, position.
• 23:15
  H. John Cooper: But what I learned from, from, some co-faculty courses is that hook is, important for achieving the femoral elevation, but it's really not as important for maintaining the femoral elevation once the femoral elevation has been achieved.
• 23:31
  H. John Cooper: you, I take the hook right out and so I, think this video probably shows that, lemme rewind just a little bit.
• 23:36
  H. John Cooper: So here are the calcar retractor and the trochanteric retractor, in place.
• 23:42
  H. John Cooper: I don't put tension on this trochanteric retractor because it will just cut right through the tensor.
• 23:48
  H. John Cooper: This is a common source of injury.
• 23:50
  H. John Cooper: so there's the bone hook going around the, around the femur and pulling anteriorly on the femur once the releases have been done,
• 24:01
  Joseph M. Schwab: So that's deep to the tensor, superficial to the femoral bone, obviously.
• 24:07
  H. John Cooper: so it's really hooking the posterior aspect of the femur and lifting it up.
• 24:12
  H. John Cooper: and when done, right around the bone, just like where you would pass a cable, there's really, in my mind, there shouldn't be concern for sciatic nerve issues.
• 24:23
  H. John Cooper: it's a very safe thing that I've probably done 5,000 times, with no, concern there.
• 24:30
  H. John Cooper: And then the femur just maintains its elevation.
• 24:33
  H. John Cooper: I think the last point is probably a subtle one and hopefully one that I think most companies' retractors, have.
• 24:41
  H. John Cooper: But this is the femoral elevator that we choose to use.
• 24:45
  H. John Cooper: there are lots of good options for this.
• 24:47
  H. John Cooper: You can see the edge of this, as I'm illustrating with the bovie, is just rounded.
• 24:51
  H. John Cooper: It's not, a flat, rectangular edge.
• 24:53
  H. John Cooper: It's a soft, curved edge, because this is going to make contact with the tensor.
• 24:58
  H. John Cooper: and a sharp edge here is certainly a risk factor for cutting through the tensor.
• 25:01
  H. John Cooper: We actually had these, further taken to a machine shop and just, ground down a little bit more to make that curve really nice and gentle, so that we're not putting, stress, through a sharp edge right at the right, at the tensor.
• 25:17
  H. John Cooper: this is a, this is the, one case that, that we filmed for this purpose.
• 25:20
  H. John Cooper: But you can see after, dislocation, the issue of tensor, it's, completely intact, no, no meaningful injury to it at all.
• 25:29
  H. John Cooper: So that's what we would grade as an intact, normal tensor without damage what we found.
• 25:37
  H. John Cooper: and so out of a hundred hips, 92 of them, using this thought process in these and these steps and these techniques and paying attention, had, minimal to no damage.
• 25:49
  H. John Cooper: so a really successful technique.
• 25:52
  H. John Cooper: Seven of the hips had moderate damage, which we've described and, quantified as 10 to 20% of the muscle volume and one hip had severe damage greater than 20%.
• 26:04
  H. John Cooper: At the top you can see an example of an, intact tensor that would make any of us happy at the end of a case.
• 26:09
  H. John Cooper: And at the bottom you can see one that had damage, which, you can see clearly.
• 26:12
  H. John Cooper: There's some muscle fibers that we transected.
• 26:15
  H. John Cooper: and we measured it at about 12%.
• 26:17
  H. John Cooper: of, the, of, the damage there.
• 26:19
  H. John Cooper: The vast majority of the tensor was intact.
• 26:22
  Joseph M. Schwab: And that you're, the 12% again is 12% of say, the width or the, length from anterior to posterior or 12%.
• 26:30
  Joseph M. Schwab: tell me a little bit more about how that number comes to be.
• 26:34
  H. John Cooper: right.
• 26:34
  H. John Cooper: We tried to flatten the tensor out as much as possible, and then measure the anterior half of the perimeter with a ruler, at the beginning of the case, on, on exposure.
• 26:45
  H. John Cooper: And then we tried to do the same thing.
• 26:47
  H. John Cooper: On, at the end and many tensors would measure, somewhere between 35 and 55 millimeters.
• 26:54
  H. John Cooper: And then we would try to quantify that transection.
• 26:57
  H. John Cooper: here it's probably five or six millimeters of, damage, which would equal about 12%.
• 27:06
  H. John Cooper: it, we couldn't wrap a circumferentially wrap the ruler around.
• 27:09
  H. John Cooper: Of course.
• 27:09
  H. John Cooper: Yeah.
• 27:09
  H. John Cooper: It would've been great if we could.
• 27:11
  H. John Cooper: and again, cross-sectional imaging, I think might've helped a little bit, but I think that.
• 27:17
  H. John Cooper: That bottom picture, unfortunately is familiar to all of us, in, in, some cases, quite a bit worse.
• 27:24
  H. John Cooper: and I think we can all see that's, not terrible damage, but it is real, real damage to the muscle fibers, there.
• 27:32
  H. John Cooper: And so we tried our best to quantify that.
• 27:34
  H. John Cooper: Unfortunately, there's nothing in the literature that, that we found that provided any sort of, validated scale for this.
• 27:40
  H. John Cooper: We had to make it up.
• 27:42
  H. John Cooper: So of the eight of the a hundred cases that had damage, again, seven were moderate, one was severe.
• 27:50
  H. John Cooper: and if you look at when it happens, none happened during exposure.
• 27:55
  H. John Cooper: Two happened during, head removal, taking the, head out, from that corkscrew, getting damage into the tensor as you were moving it back and forth.
• 28:08
  H. John Cooper: None happened during acetabular preparation.
• 28:11
  H. John Cooper: And then the, vast majority, six of the eight happen during femoral exposure or femoral preparation.
• 28:16
  H. John Cooper: So, mainly when you're trying to lift that femur up, if you don't have the releases done and that, that lateral trochanteric retractor, is trying to press down a little bit, it can cut through the tensor fibers at that point.
• 28:31
  H. John Cooper: or when you're broaching you needed just a little bit more room to get the broach in and you push down a little bit.
• 28:35
  H. John Cooper: as you're trying to get a bigger size broach in, we had a couple cases where that happens.
• 28:40
  H. John Cooper: and that's where the one severe damage one happened is we'd done a good job, the whole case of preserving the tensor, and we were broaching in a, pretty tight patient and, pushed down on that lateral trochanteric retractor and the tensor just really opened up, I think about, 25 or 30%.
• 28:55
  Joseph M. Schwab: So one question I have about, the way you classified that, damage and especially when you classified it during a procedural step is, as soon as damage occurred, did they then stop having the steps noted or could a patient be noted to have damage in multiple steps?
• 29:17
  Joseph M. Schwab: the reason I ask is it's not uncommon that once you develop some damage to the tensor small amount or a moderate amount, that, that can, propagate a bit during surgery, especially if it's a difficult hip and you continue to put some tension across the wound.
• 29:36
  H. John Cooper: You're, absolutely right and you're, you hit on a key point that I stressed to, to, to everybody I'm trying to teach this to in my operating room is, you really gotta respect it because once the damage starts, it's almost like a little, tear and a piece of cloth, it can just really propagate.
• 29:51
  H. John Cooper: So we did continue to quantify that it's not placed in this chart, but as you can see that almost there were only two cases where it happened before the femoral exposure in broaching.
• 30:04
  H. John Cooper: In, in those two cases, it did propagate a little bit more.
• 30:08
  H. John Cooper: We didn't quantify a percentage that happened early and an additional percentage that happened later, but, in those two cases, it certainly did propagate and, get worse over time.
• 30:20
  H. John Cooper: so trying to preserve the fibers and keep it completely intact is really, helps to, prevent damage later in the case.
• 30:31
  H. John Cooper: I think that the takeaway points from this study for us are that the significant risk factors, what we found in terms of results, the significant risk factors that put patients at risk, of those eight patients where we had injury.
• 30:43
  H. John Cooper: the significant factors were, two of them were things you could look at from a radiograph and say, this is going to be a more difficult exposure.
• 30:53
  H. John Cooper: we're gonna have a tighter hip, and we're gonna struggle a little bit more.
• 30:58
  H. John Cooper: and those were a varus, femoral neck shaft angle, and a wide iliac crest.
• 31:05
  H. John Cooper: you can see that wide iliac crest, affected things to a greater degree than the femoral neck shaft angle.
• 31:11
  H. John Cooper: But that wide iliac crest, makes the exposure significantly harder of the femur, and really puts patients at risk for this.
• 31:19
  H. John Cooper: And the third risk factor, goes back to something I alluded to earlier, which is the stem design.
• 31:25
  H. John Cooper: when we used the submitted stem, we had a greater risk of, of, tensor damage.
• 31:30
  H. John Cooper: And we did this as a multi-variate, regression.
• 31:33
  H. John Cooper: So you would think it might be the patient's older age.
• 31:38
  H. John Cooper: These tend to be older women that we were using cement on, but those were not independent risk factor.
• 31:43
  H. John Cooper: It was really just the cemented stem itself, that was a risk factor.
• 31:46
  H. John Cooper: And in my mind, this is because to put a cemented stem in, I need more femoral exposure.
• 31:51
  H. John Cooper: I need a greater shot, a greater straight shot down the canal, to, do a good job in introducing the cement gun and putting a, a longer, tends to be a little bit straighter stem, at least the one that I use, into the canal.
• 32:08
  H. John Cooper: When you need that greater femoral exposure, and you need the femur further up, you're more likely to have, some tensor injury.
• 32:15
  H. John Cooper: the things that weren't significant for us were gender, age, BMI, not significant at all.
• 32:20
  H. John Cooper: bikini versus longitudinal.
• 32:22
  H. John Cooper: We found no difference, in the femoral neck length.
• 32:24
  H. John Cooper: There was a trend, like longer necks were a little bit more protected, but that we didn't, find statistical significance without.
• 32:32
  H. John Cooper: that, that sort of.
• 32:33
  H. John Cooper: It goes back to how we've always talked about the, if you're going through a learning curve, the easier cases are gonna be those with a narrow pelvis and a long valgus femoral neck because you're gonna have a lot more room for femoral exposure in those cases.
• 32:48
  H. John Cooper: And, we found that, even in, an experienced surgeon's hands, when we had the opposite of a, wide pelvis, a short neck, and needing more femoral exposure.
• 33:00
  H. John Cooper: We were still apt to damage the tensor, significantly more often.
• 33:05
  H. John Cooper: Clinical outcomes.
• 33:06
  H. John Cooper: I don't think we were really powered for this honestly.
• 33:09
  H. John Cooper: but looked at the eight patients who had some tensor damage.
• 33:12
  H. John Cooper: And, only one of those really had severe damage.
• 33:16
  H. John Cooper: but we didn't see any trends in terms of changes in, in, patient reported outcomes between patients with none versus, moderate or severe damage with, the metrics that we used, my guess is there's probably a little bit of, of, clinical difference.
• 33:32
  H. John Cooper: but certainly the frequency where we were seeing it, the degree of damage that we were seeing and The, the nature of the outcome scores that we used didn't, show us this.
• 33:44
  H. John Cooper: So conclusions, I think that, with when you're out of the learning curve and when take care to take a few extra steps to preserve the TFL, which really don't add much time at all, just seconds.
• 33:57
  H. John Cooper: that severe damage can almost always be avoided, with careful surgical technique.
• 34:02
  H. John Cooper: And that moderate damage can still occur occasionally.
• 34:06
  H. John Cooper: And the patients where you would worry about this for, and the patients that I try to do a bigger release on are those with a wide iliac wing, a short varus femoral neck shaft angle.
• 34:16
  H. John Cooper: And, certainly those, when I'm using a cemented stem, I'm gonna do a little bit more work to expose that hip, to try to make that case easier and, and not put the tensor at risk.
• 34:26
  H. John Cooper: I think the clinical relevance of this study, and I do think there's some clinical relevance here, is that understanding these risk factors, and, the maybe incorporating a few of these, these, technique changes into your, anterior approach technique.
• 34:42
  H. John Cooper: you can really, help to, navigate a learning curve, preoperatively plan for what releases you might wanna do.
• 34:50
  H. John Cooper: And, and, think about intraoperative decision making about when to extend your release.
• 34:56
  H. John Cooper: when to really open up that tensor fascia more to free that muscle so it doesn't get damaged, and so you have an easier time, during the case.
• 35:04
  H. John Cooper: Limitations, this is a single surgeon study.
• 35:06
  H. John Cooper: It just may, this may not be applicable to everybody.
• 35:09
  H. John Cooper: I think the sample size issues with some of the clinical outcomes are, probably not great.
• 35:15
  H. John Cooper: and that the, the, both the measurements of tensor damage that we made during the case and also the radiographic measurements, could be subject to, to, a measurement projection, bias.
• 35:29
  Joseph M. Schwab: So first of all, congratulations on completing a study like this.
• 35:34
  Joseph M. Schwab: It's, I was listening to a talk by Dan Berry and he was talking about how difficult it is in modern orthopedics to do a prospective, study on patients.
• 35:45
  Joseph M. Schwab: He was specifically talking about prospective randomized studies.
• 35:48
  Joseph M. Schwab: Completing any sort of prospective study, it can be, significantly challenging, especially when it involves surgery and surgical technique.
• 35:58
  Joseph M. Schwab: Did you have any difficulty recruiting patients for it or was it pretty much a no-brainer?
• 36:03
  H. John Cooper: This was, an observational study, so we weren't treating anybody differently, so we had no trouble recruiting patients.
• 36:08
  H. John Cooper: We just told them we were gonna take measurements, during, their surgery and not do anything differently than what I was already doing.
• 36:16
  H. John Cooper: and so nobody had issues with that.
• 36:18
  Joseph M. Schwab: Do you think there's appreciable difference in how the tensor is either protected or not when you compare large scale differences in technique, and let's just take the easy one and say on table versus off table, anterior approach.
• 36:34
  H. John Cooper: I think, that the differences, are probably more related to the nuance in the surgical technique more than the off table versus on table.
• 36:46
  H. John Cooper: I think that if you really try to keep that tensor, tightly bound in the fascia by making a small fascial incision, that might be a bit more medial and not doing an adequate release of the femur, you're gonna put that tensor at a significantly greater risk of injury, whether you're on a standard table or on a specialized table.
• 37:07
  H. John Cooper: Whereas I think if you're, attentive to those steps and you do a really good job with your femoral releases, your capsular management, and you can give that tensor a little bit more breathing room, by opening the fascia a little bit more and being a bit more lateral, you're gonna have a much higher success rate of saving that tensor.
• 37:23
  H. John Cooper: Again, whether you're on a standard table or a specialized table.
• 37:26
  Joseph M. Schwab: So it really sounds, if there's one takeaway for listeners or especially residents or fellows, it really sounds to me like that fascial release at the beginning, undermining your incision and going proximal and distal and releasing as much of that fascia is probably the number one thing that they could do to help protect the tensor.
• 37:46
  Joseph M. Schwab: Am I understanding that correctly?
• 37:48
  H. John Cooper: I, think that's an easy, it's a very easy change to incorporate into your practice tomorrow.
• 37:52
  H. John Cooper: There's very little learning curve for that.
• 37:53
  H. John Cooper: I don't think it's something that I would feel comfortable putting a knife or a scissor and just running it blindly, sharply, all the way up to the crest.
• 38:01
  H. John Cooper: So it's something I do bluntly with my finger.
• 38:02
  H. John Cooper: So a sharp dissection while I can see with my eyes.
• 38:05
  H. John Cooper: and then a blunt dissection all the way up to the iliac crest.
• 38:09
  H. John Cooper: and, as far distally as my finger can reach, so that I'm not injuring nerves or, small vessels.
• 38:16
  Joseph M. Schwab: And one other question, at least regarding these patients, is there any possibility to bring them back for advanced imaging, say at one year, two years, things like that, to see if there's any long-term damage to the TFL?
• 38:30
  H. John Cooper: I think there, there is a possibility to do that.
• 38:33
  H. John Cooper: I think it would be a more robust study if we had preoperative imaging to compare to.
• 38:37
  H. John Cooper: And, unfortunately in none of these a hundred patients, I, don't believe we have any.
• 38:41
  H. John Cooper: So it, it would be something that would be a big resource commitment, Joe, and, probably not as good as a second prospectively designed study where we could capture that preoperative imaging and, postoperative imaging, which we've done before and for other reasons, but not, with these concerns in mind.
• 38:59
  Joseph M. Schwab: Yeah.
• 39:00
  Joseph M. Schwab: John, I really want to thank you for sharing, this technique, this data, this study, with certainly the folks who were at the AHF annual meeting, as well as with our listeners on the AHF podcast.
• 39:13
  Joseph M. Schwab: And like I said, congratulations on performing such a, an impressive study, that I really think answers one of the key questions in anterior approach, which is how muscle sparing are we and how can we make sure we're doing it as good as possible?
• 39:30
  H. John Cooper: Thank you Joe.
• 39:31
  H. John Cooper: Alright, and thank you for the kind invitation to join you today.
• 39:34
  Joseph M. Schwab: Thank you for joining me for this episode of the AHF podcast.
• 39:38
  Joseph M. Schwab: If you have a scientific paper, a case report, or a technique paper that you're interested in submitting to the AHF 2026 annual meeting, the call for submissions is open now.
• 39:51
  Joseph M. Schwab: There's a deadline of March 1st, so get yours in today.
• 39:55
  Joseph M. Schwab: There are awards for best scientific paper, best case report, and best technique paper.
• 40:02
  Joseph M. Schwab: I'll put a link to the website in the description.
• 40:05
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• 40:13
  Joseph M. Schwab: Please also drop any topic ideas or feedback in the comments below.
• 40:18
  Joseph M. Schwab: 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.
• 40:31
  Joseph M. Schwab: All one word.
• 40:33
  Joseph M. Schwab: Episodes of the AHF podcast come out on Fridays.
• 40:37
  Joseph M. Schwab: I'm your host, Joe Schwab, asking you to keep those hips happy, healthy, and free of TFL damage.