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Rethinking TFL Injury in Anterior Approach THA

• Anterior Hip Foundation • Season 2 • Episode 32

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Protecting the Tensor Fascia Lata in Anterior Approach Total Hip Arthroplasty

🎥 Welcome to the AHF Podcast! Join host Joe Schwab as he dives deep into a revealing and award-winning study on tensor fascia lata (TFL) injury during anterior approach total hip arthroplasty with special guest H. John Cooper. Dr. Cooper shares insights from his prospective study presented at the 2025 AHF annual meeting, discussing how often TFL injuries occur, the critical steps to minimize such injuries, and how these findings can influence surgical techniques. This episode is packed with invaluable tips for surgeons at all levels, emphasizing the importance of preserving the TFL for optimal patient outcomes. 🏥💪 

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Are you interested in presenting a scientific paper, case report, or technique video/paper at the 2026 AHF Annual Meeting? Check out our Call For Submissions here:

https://anteriorhipfoundation.com/ahf-2026-nashville/anterior-hip-foundation-2026-call-for-submissions-2026/

Make sure you hurry, submission deadline is March 1st, 2026!

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Host: Joseph M. Schwab, MD
Guest: H. John Cooper, MD

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⚠️ Medical disclaimer: This content is for education and professional discussion only and is not medical advice. Patient details have been de-identified.

#AHFPodcast #AHFCallForSubmissions #AnteriorHipFoundation #AHF #AnteriorApproach #TotalHipArthroplasty #HipReplacement #Orthopaedics #MedicalEducation

Joseph M. Schwab:

Hello and welcome to the AHF Podcast. I'm your host, Joe 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. But as with many things in surgery, what we intend to spare isn't always what we actually spare. One important, occasionally overlooked and often abused muscle and anterior approach, especially among surgeons in their learning curve, is the tensor fascia lata. 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. 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. It asked a simple but important question, how often are we really injuring the TFL during anterior approach total hip? When does that injury occur and what factors increase the risk? today I'm joined by H. John Cooper, who presented that award-winning work. 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. So to help us rethink the TFL injury in anterior total hip, let's welcome to the show H. John Cooper. John, welcome to the AHF Podcast. I.

H. John Cooper:

Hi. Glad to be here.

Joseph M. Schwab:

S You, were able to present this at our, 2025 AHF meeting in Nashville. And can you tell me a little bit about why this was, a presentation that you decided to submit, for our call for submissions?

H. John Cooper:

this is a, project that, that, I've been thinking about for some time. 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. And, I certainly believe I do a much better job at this point in my practice than I did during my learning curve. And I, think we were curious about how often we were preserving the tensor completely, and when we weren't. Why, what were the, who were the patients at risk and what were the steps where it would be most likely to be injured? and I think that was the, reason that we wanted to do the study. And, a brilliant, student who was with me for two years, Caitlin Wolfel, pushed me to do this. And, luckily we had the resources to have somebody there. live during every surgery. 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

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. Is that right?

H. John Cooper:

I do with some pictures and, our, thought process behind this. I'd be happy to share it. This is, a few slides about, what we intended to do, in the study and, what we found. 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. That wasn't my focus during the case. I was doing the surgery like I always do. but I had somebody, an observer, looking at the tensor at every, at every case, at every step. I, have some disclosures, but certainly nothing relevant to the, to this case. So the, TFL as you, talk about in the introduction is, an often overlooked muscle. You can't overlook it when you're, going into the direct anterior hip that's right there. You have to find it to make sure you're in the right interval. but once we get around it, we tend to forget about it. 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. And it's often, in unintentionally maybe sacrificed or, injured, while we're trying to do a good job inside the, hip joints. and especially this is something, at least with me, that was more common during my learning curve. and I think, certainly became less with time and. So I think it remains a bit of a cause for concern. 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. 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. 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. so the, I'll, briefly, talk about the steps for, TFL preservation that I, think are important. and Joe, for some context, I am a hundred percent anterior surgeon. I don't select. specific cases, every, patient who's a candidate for a total hip gets an anterior hip with me. and, have been for, for 14 years now. 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. I think this makes a tremendous difference. 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. something that at least in my hands, I think helps is utilizing offset reams and offset cup inserters that can glide over the tensor. The most common place that we, we, have found injury is, preparing the femur. 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. We looked at a hundred consecutive cases, done between, toward the end of November of 24 and, beginning of March of 25, all comers. We weren't selecting, we excluded revisions, we excluded conversions, but all primary, total hip arthroplasties done by me. over a range of pathology. Were our study group. we looked at a lot of variables. We looked at all the patient demographics that you would expect in this kind of a study. We quantified how often the tensor was being damaged at all. and if so, the amount of damage, none minimal, less than 10%, moderate damage, 10 to 20% severe damage, greater than 20%. And, how did we do this? ideally we could have done this with, CT or MRI, to quantify, from preoperative to postoperative, any sort of, volume loss in the muscle. But we, we, didn't do that. we did it, in surgery. We were able to measure. 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. And, with that same, flexible ruler, try to quantify as a percentage of the tensor volume. How much of it was injured? 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. And, she was a hard grader. we also quantified when it was damaged, so we would inspect it, multiple, at multiple steps throughout the case. see is it still intact or was it damaged? 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. 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. and then a couple other things. We considered bikini versus longitudinal incision. I did both during this time. the majority were bikini, some were longitudinal. We wanted to see if that had any effects. Also form of fixation cemented versus cementless stems, again, which I was doing both, probably 15 or 20% cemented during this time. 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. and I've got a video that shows, some of these steps. This is the video that we presented at AHF, in June of 25. I'm happy to go. through this or, and hopefully it'll show some of the, some of the techniques. But this is the bikini incision in a, patient with standard arthritis, of the hip here. I really wanted to highlight what I think is one of the most important steps in, in, in trying to preserve the tensor. Is really how you enter the tensor and how you manage the tensor. So through this bikini incision, I'm developing a plane just on top of the muscle. I'm looking at the tensor fascia. So the fascia overlying the muscle fibers right there. 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. And what that does is that keeps most of the fascia medial. And when you keep most of the fascia medial, the tensor has more excursion laterally during the case. It's not tethered by the fascial sheath. 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. And I think this is really critical. 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. Way proximal and way distal from what my knife, from where my knife goes. 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. and that to me, I think is the biggest tip. 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. and, that's made the biggest difference. step two is, one area where the tensor can be injured is, from the saw. You can see it's right there, right behind that retractor. And some patients are certainly more than others, but the side of the saw. can be injured, can injure the medial fibers of the tensor. You can see how close the saw blade is coming to the tensor right there. So abducting the leg a little bit, can help move the tensor away and just being really careful about that side of the saw.

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. but te tell me a little bit about your capsular management. Are you capsulotomy capsulectomy? And if you do capsulotomy, do you tag the capsules? tell me a little bit about that.

H. John Cooper:

It's a good, it's a really good question. 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. And when I reach the distal insertion of the capsule, I'll go medially and later. I don't think this matters so much for preserving the tensor. It matters a tremendous amount for femoral exposure later. the medial limb for me is a variable release. I don't wanna over release in patients, who are quite flexible because I think this is an instability risk. 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. Later in the case. It doesn't matter for me so much right now. 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. But I wouldn't dream of trying to expose a femur without that capsule released from the saddle. because I think that, that, makes the femoral exposure so much harder,

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?

H. John Cooper:

Tag'em with a suture. and use them as retractors. it what I don't, or when one of my stitches, breaks off. 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. 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.

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. It could sometimes just slide right through that tensor muscle. 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.

H. John Cooper:

Absolutely. 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. So I, rare, I rarely put tension on those sutures. 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.

Joseph M. Schwab:

Yeah, I,

H. John Cooper:

This is an area where I, have certainly myself entered the tensor many times. and, I don't do a napkin ring. I do a single cut. In most patients, unless they're really stiff and the head doesn't move at all, then napkin ring can be quite helpful. But for me it's a single cut. and try to flip that head up so I can, get a corkscrew into the head, to remove it. I think you're probably less likely to dance damage the tensor with a napkin ring cut.

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. I, so I, it's a good point and it's a good question. I don't know.

H. John Cooper:

Exactly. I, think there, there's certainly, risks and benefits to both techniques a napkin ring or a, or a single cut. for most patients who aren't, severely contracted, a single cut works quite fine. 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. 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. So here the capsule's been opened. the head is flipping up and you're looking right at the cut surface of the femoral neck. this court where try to put right in the center position, like you go to cephalomedullary, screw in the nail. Right toward the apex. And, I, I try not to put this in until I get that good exposure of the cut surface of the neck. but this is critical at this point. What, do I do with this? 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. And that is something that can really cut through the tensor. And I've injured, more tensors than I'd like to admit that way. So this, to me is something that you can never do, in my operating room, is try to bring that posterior. 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. And you'll see me try to do that so proximally distally right in line with the fibers. And when you do that, after the head is spun, the head almost always pops off, pops out quite well, with that. 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. And that is something that's quite atraumatic for the tensor, and the rectus anteriorly. This is a bikini incision. 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. So using an offset here. 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. It's a little bit of a different feel, but it's worked well for me.

Joseph M. Schwab:

It looks like you do quite a bit of acetabular preparation and implant placement, acetabular component placement, with no retractors in. Is that correct?

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. So taking that anterior retractor out at least is, something that can be quite helpful. I usually leave the posterior retractor in. Joe I think I took it out for that video just to show the tensor, but just show how we get around the tensor. But typically I'm leaving posterior retractor in. So the most common place that we injured the tensor was, on femoral exposure either during the exposure and elevation or, during broach entry. and I'm, not gonna go into detail about the femoral releases. we've, we published a few papers And video techniques on this, as have many other people. 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. 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.

Joseph M. Schwab:

Let me ask you a little bit,'cause this part is really, crucial. I think there's differences in. Levels of femoral exposure between different styles of anterior approach. So can you talk a little bit about your common setup? Are you doing this on a standard table? Are you doing it on an orthopedic table? Are you doing it with any sort of additional equipment that allows for exposure or limb positioning?

H. John Cooper:

I'm doing this on a standard table. I keep the table. flat And, I extend the foot of the table about 20 or 25 degrees. 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. 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. So both legs for me are draped into the field. I don't have somebody or, an assistant on the operative leg providing tension. It just hangs where it needs to go. 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. it's a, very nice, exposure and the style of stem I think matters. So, most of the stems that I, I think many people are using now are. A slightly shorter, recessed shoulder, type stem, like a triple taper, a double taper stem. 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. so we can get away with just a little bit less exposure than, and at least I needed, and in 20, in 2012.

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.

H. John Cooper:

Yeah. So good, point. many of the orthopedic tables, that are designed for anterior approach have a femoral elevator built into them. 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. And I use that to elevate the femur anteriorly after the releases have been done. I used to use, I think for eight or nine years, a table mounted hook that would stay in that, position. 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. you, I take the hook right out and so I, think this video probably shows that, lemme rewind just a little bit. So here are the calcar retractor and the trochanteric retractor, in place. I don't put tension on this trochanteric retractor because it will just cut right through the tensor. This is a common source of injury. so there's the bone hook going around the, around the femur and pulling anteriorly on the femur once the releases have been done,

Joseph M. Schwab:

So that's deep to the tensor, superficial to the femoral bone, obviously.

H. John Cooper:

so it's really hooking the posterior aspect of the femur and lifting it up. 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. it's a very safe thing that I've probably done 5,000 times, with no, concern there. And then the femur just maintains its elevation. I think the last point is probably a subtle one and hopefully one that I think most companies' retractors, have. But this is the femoral elevator that we choose to use. there are lots of good options for this. You can see the edge of this, as I'm illustrating with the bovie, is just rounded. It's not, a flat, rectangular edge. It's a soft, curved edge, because this is going to make contact with the tensor. and a sharp edge here is certainly a risk factor for cutting through the tensor. 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. this is a, this is the, one case that, that we filmed for this purpose. But you can see after, dislocation, the issue of tensor, it's, completely intact, no, no meaningful injury to it at all. So that's what we would grade as an intact, normal tensor without damage what we found. 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. so a really successful technique. 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%. 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. And at the bottom you can see one that had damage, which, you can see clearly. There's some muscle fibers that we transected. and we measured it at about 12%. of, the, of, the damage there. The vast majority of the tensor was intact.

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%. tell me a little bit more about how that number comes to be.

H. John Cooper:

right. 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. And then we tried to do the same thing. On, at the end and many tensors would measure, somewhere between 35 and 55 millimeters. And then we would try to quantify that transection. here it's probably five or six millimeters of, damage, which would equal about 12%. it, we couldn't wrap a circumferentially wrap the ruler around. Of course. Yeah. It would've been great if we could. and again, cross-sectional imaging, I think might've helped a little bit, but I think that. That bottom picture, unfortunately is familiar to all of us, in, in, some cases, quite a bit worse. and I think we can all see that's, not terrible damage, but it is real, real damage to the muscle fibers, there. And so we tried our best to quantify that. Unfortunately, there's nothing in the literature that, that we found that provided any sort of, validated scale for this. We had to make it up. So of the eight of the a hundred cases that had damage, again, seven were moderate, one was severe. and if you look at when it happens, none happened during exposure. 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. None happened during acetabular preparation. And then the, vast majority, six of the eight happen during femoral exposure or femoral preparation. 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. 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. as you're trying to get a bigger size broach in, we had a couple cases where that happens. 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%.

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? 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.

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. 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. In, in those two cases, it did propagate a little bit more. 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. so trying to preserve the fibers and keep it completely intact is really, helps to, prevent damage later in the case. 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. 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. we're gonna have a tighter hip, and we're gonna struggle a little bit more. and those were a varus, femoral neck shaft angle, and a wide iliac crest. you can see that wide iliac crest, affected things to a greater degree than the femoral neck shaft angle. But that wide iliac crest, makes the exposure significantly harder of the femur, and really puts patients at risk for this. And the third risk factor, goes back to something I alluded to earlier, which is the stem design. when we used the submitted stem, we had a greater risk of, of, tensor damage. And we did this as a multi-variate, regression. So you would think it might be the patient's older age. These tend to be older women that we were using cement on, but those were not independent risk factor. It was really just the cemented stem itself, that was a risk factor. And in my mind, this is because to put a cemented stem in, I need more femoral exposure. 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. When you need that greater femoral exposure, and you need the femur further up, you're more likely to have, some tensor injury. the things that weren't significant for us were gender, age, BMI, not significant at all. bikini versus longitudinal. We found no difference, in the femoral neck length. There was a trend, like longer necks were a little bit more protected, but that we didn't, find statistical significance without. that, that sort of. 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. 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. We were still apt to damage the tensor, significantly more often. Clinical outcomes. I don't think we were really powered for this honestly. but looked at the eight patients who had some tensor damage. And, only one of those really had severe damage. 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. 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. 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. that severe damage can almost always be avoided, with careful surgical technique. And that moderate damage can still occur occasionally. 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. 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. 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. you can really, help to, navigate a learning curve, preoperatively plan for what releases you might wanna do. And, and, think about intraoperative decision making about when to extend your release. 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. Limitations, this is a single surgeon study. It just may, this may not be applicable to everybody. I think the sample size issues with some of the clinical outcomes are, probably not great. 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.

Joseph M. Schwab:

So first of all, congratulations on completing a study like this. 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. He was specifically talking about prospective randomized studies. Completing any sort of prospective study, it can be, significantly challenging, especially when it involves surgery and surgical technique. Did you have any difficulty recruiting patients for it or was it pretty much a no-brainer?

H. John Cooper:

This was, an observational study, so we weren't treating anybody differently, so we had no trouble recruiting patients. We just told them we were gonna take measurements, during, their surgery and not do anything differently than what I was already doing. and so nobody had issues with that.

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.

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. 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. 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. Again, whether you're on a standard table or a specialized table.

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. Am I understanding that correctly?

H. John Cooper:

I, think that's an easy, it's a very easy change to incorporate into your practice tomorrow. There's very little learning curve for that. 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. So it's something I do bluntly with my finger. So a sharp dissection while I can see with my eyes. and then a blunt dissection all the way up to the iliac crest. and, as far distally as my finger can reach, so that I'm not injuring nerves or, small vessels.

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?

H. John Cooper:

I think there, there is a possibility to do that. I think it would be a more robust study if we had preoperative imaging to compare to. And, unfortunately in none of these a hundred patients, I, don't believe we have any. 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.

Joseph M. Schwab:

Yeah. 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. 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?

H. John Cooper:

Thank you Joe. Alright, and thank you for the kind invitation to join you today.

Joseph M. Schwab:

Thank you for joining me for this episode of the AHF podcast. 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. There's a deadline of March 1st, so get yours in today. There are awards for best scientific paper, best case report, and best technique paper. I'll put a link to the website in the description. And as always, please take a moment to like and subscribe so we can keep the lights on and keep sharing great content just like this. Please also drop any topic ideas or feedback 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. Episodes of the AHF podcast come out on Fridays. I'm your host, Joe Schwab, asking you to keep those hips happy, healthy, and free of TFL damage.

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