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CME Foot Conditions

A Primer on Posterior Tibial Tendon Dysfunction

Ryan Fitzgerald,

Ryan Fitzgerald, DPM presents an overview of the common symptoms, risk factors, pathophysiology, diagnostic tests, classifications and treatment options for unilateral progressive flatfoot deformity resulting from posterior tibial tendon dysfunction. Throughout the presentation, Dr Fitzgerald offers clinical pearls as well as the latest findings found in the literature. Ultimately, Dr Fitzgerald urges the viewer to perform a systematic evaluation of these very complex patients in order to identify appropriate treatments.

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Goals and Objectives
  1. Review the pathophysiology of posterior tibial tendon dysfunction.
  2. Describe the function of the posterior tibial tendon.
  3. Recognize appropriate physical exam findings for patients with progressive unilateral flatfoot.
  4. Identify the stages as described by Johnson & Strom and Myerson.
  5. Evaluate radiographs for patients with flatfoot deformity.
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  • CPME (Credits: 0.5)

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    PRESENT eLearning Systems, LLC has approved this activity for a maximum of 0.5 continuing education contact hours.

    Release Date: 03/16/2018 Expiration Date: 12/31/2020

  • Author
  • Ryan Fitzgerald,

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    Ryan Fitzgerald none

  • Lecture Transcript
  • Okay. For those of you who didn’t get the [indecipherable] [00:05], I guess, is that I got a call from the chief of surgery today while I was upstairs in the hotel getting ready for the lectures because apparently, somebody had decided that the case images that I had in my Facebook page were a HIPAA violation, and so I’m in big trouble with them. So, they’re now no longer on my Facebook page. But I’m going to be talking about posterior tibial tendon dysfunction or adult acquired flatfoot deformities. I’m Ryan Fitzgerald, I do practice in Virginia. So, any time you have a discussion about the posterior tibial tendon, it’s important to review the anatomy. Because we all think we know it, but I think we don’t know it as well as we think that we do. And I know that it’s complicated, but it’s important to think of where it is and in conjunction with the rest of the other structures in the foot. This diagram shows the overall course down to the navicular tuberosity, but it’s also important to consider the function of the posterior tibial tendon that it is plantar flexor and it also is an invert of the midfoot, but also creates hindfoot, eversion rather inversion. The single leg toe rise, when you go up on your toes and the heel swing in, that’s going to be the posterior tibial tendon. And so it’s important to consider these functions as we’re evaluating our patients. Both in the areas that they have pain, but also in the functions that they have the ability to do or not to do. And so it’s more to think of that moving forward. So, symptomatic adult acquired flatfoot or posterior tibial tendon dysfunction. These patients traditionally present with pain and swelling along the course of the tendon. So it’s along the medial ankle, exhibiting down into the area of the navicular tuberosity, usually worse barefoot or uneven terrain that are in a shoe or within a support or a bit of a heel. Ultimately these patients will demonstrate and will relate to a lost of the medial arch progressively. They’ll feel that their arches are flattening particularly if you ask them when they get out of the shower and they step down on the ground do they notice one foot print is bigger than the other. Things like that. They may have weakness and inability to stand up on the toes and that’s a single leg toe raise we were talking about. And then they have tenderness in the midfoot, especially during stress activities on uneven terrain. It’s really big. And so it’s important to think about the pathomechanics. Traditionally, we were all educated to believe that it is an issue with the posterior tibial tendon alone. And the reality is the literature doesn’t necessarily support that anymore, but indeed it is a combination of issues with regard to the tendon, but also the ligament structures that are in the hindfoot complex. And it’s a combination of these ligamentous laxities and attenuation of the ligaments in conjunction with weakening of the posterior tibial tendon that ultimately progresses towards this progressive flatfoot deformity. The loss of the posterior tibial tendon will cause dysfunction in the foot during gait. And it’s that loss, that dysfunction that ultimately puts the additional stresses and strains on the ligaments in the hindfoot commonly the spring ligament in particular. And Deland in Foot and Ankle International in 2005 showed this. And they actually found that in cadaver specimens that they cut the posterior tibial tendon, they didn’t necessarily have a progressive flatfoot. So, the absence of the tendon didn’t just make the foot go flat. The ligaments were still intact and ultimately the ligament continuation over time became the source of that progressive flattening of the foot. So it’s important to know. So it’s not just the tendon problem when you have these patients. Progressive flatfoot deformity often occurs in patients that are over 40, predominantly women all though not necessarily. And maybe due to inherent abnormality of the tendons, but also the ligaments that we discussed about. Other risk factors include obesity. Certainly, the more weight you’re carrying on the feet, the greater the stresses and strains that are likely to be contributing across them. Diabetes, hypertension, previous history of trauma or surgery, anything that was going to cause a leg length discrepancy, you’re going to put increasing strain on the tendon itself. Previous history of local steroid injections. I had a patient that came in last week ultimately who had been seeing another provider in town for posterior tibial tendonitis and have received a series of injections around the navicular tuberosity and then suddenly had increasing pain swelling and ultimately a tendon rupture with the arch collapsed. And there are other inflammatory things Reiter syndrome, psoriasis, spondyloarthropathy. They can cause this localized manifestation of a systemic disorder. The best classifications or at least the most common is the Johnson’s Strom Classification which was written in 1989. And it was later modified by Myerson to give a fourth category. And it’s important to think through these and it’s an okay classification system. At least it’s well understood and it’s well discussed. But in stage one essentially you have pain and swelling. So you have the foot that looks like a normal foot, but the patient is complaining of pain. They have the medial aspect of the foot along the course of the tendon, tenosynovitis and some degeneration of the tendon but largely the tendon is in tact if you get an MRI. There is no structure deformity or position changed and that’s really important to think about. The hindfoot is still mobile and the patient does demonstrate the ability to perform a single leg toe raise.

    [05:03] As we progress through the stages, you see that there are a variety of different treatments per each stage. Stage two on the other hand is more of a dynamic deformity. You’re starting to get some deformity but it’s still relatively flexible. And ultimately this is too broad category. And as you read the literature moving forward, you see that they’re starting to further subdivide stage two into early stage two and late stage two and now even up to A through E in stage two. And I have a slide that will show that for you. But in stage two, the tendon is attenuated or fully ruptured and the patient loses that ability to perform the single leg toe raise that their heel doesn’t swing into inversion. There is midfoot pronation and forefoot abduction. And the subtalar joint still remains mobile. So you don’t have those arthritic compensatory changes. And so you can imagine through the course of stage two that there’s a fairly broad degree of the symptoms that are happening from attenuation of the tendon to inability to perform the toe raise. And that’s ultimately why the stage two deformities are kind of too broad of a category. As we discussed, the stage two early is more characterized by inflammation, hindfoot pain and things like that. It’s kind of a lesser degree of the stage two. And then as you progress to later stage two, you have that in conjunction with positional change and start having this flexible flatfoot deformity that is reducible and is still mobile in the hindfoot. And then ultimately, moving on to stage three, you get to affix deformity. This is where these deformity forces become rigid and so you start to have a rigid hindfoot valgus position that doesn’t reduce. You can’t manipulate back into position. And it’s characterized by all of the previous symptoms as well as now the beginnings of lateral impingement symptoms along the lateral aspect of the foot inferior to the fibula and in conjunction with this rigid fixed hindfoot deformity. And then stage four which is the Myerson addition is essentially everything in stage three but the addition of ankle valgus position. And this ankle valgus deformity is a consequence of instability and attenuation of the deep deltoid ligaments and the ankle starts swinging the valgus as a consequence of this persistent increasing valgus stresses across the foot and ankle. So, when you consider these patients and you think about the clinical workup, it’s important to obtain a good history and our office has a history and physical sheet that we have the patients fill out. And this is just a snippet that I found particularly amusing. This particular patient felt that rap music made his pain worse. So, we encouraged him to not listen to rap music and to call us if he had any problems. But it’s really important to get a good history because often there’s going to be something. The patients, if you listen to what they’re saying, they will ultimately tell you what’s going on. So it’s really important to hear them and ask the right questions. A physical and biomechanical exam is tremendously important and you want to check both extremities. Commonly this is more unilateral but it’s important to establish what the other limb looks like, you know, what’s happening on the other side because it may be just their standard normal position. You want to evaluate them both in there weight bearing and non-weight bearing, in positions ultimately to determine the flexibility or the rigidness of the flatfoot. Obviously as you progress through the classifications, the more rigid it becomes. That changes the types of procedures you’re going to do to try to make it better. And you want to evaluate the degree and type of the equinus. When I was at Barry, Dr. Merrell who was our surgery professor said all flat feet have equinus and I have found it to be true so far. I don’t know that it’s absolute. There is no all ever any absolute but certainly with regard to flatfoot deformities, the equinus deformity is a driving force. And so it’s important to really deal with that as you’re thinking about how you’re going to go overall, because if you don’t, you’re ultimately going to be kind of spinning your wheels, because any other correction that you perform is going to have to work against that equinus deformity. So I would definitely encourage you to look for the equinus. I imagine you’ll find it more often than not. This is just a picture showing that single leg toe raise. You can see the heel is coming in the inversion as they come up off the ground. Radiographic evaluation. It’s always important to get good x-rays on these. And ultimately, you’re going to get the standard three views. What is most helpful on the DP view is you’re going to see the increasing Kite’s angle, ultimately, 20 degrees or more. And then the calcaneocuboid angle, the abduction of the forefoot on the hindfoot is going to increase as well. You’ll also have decreased talonavicular congruency. And ultimately you’re just seeing the navicular and the talus is kind of sliding off. The talus is sort of rotating around medially and then the navicular going laterally. And those are fairly classic and sort of pathognomonic findings radiographically. On the lateral and as you can see an aberration of Meary’s angle and this is a good picture of that. You can see that the talar declination angle as compared to the first metatarsal supply section as compared to the top. As well, you’ll see navicular bridge angle which is essentially seeing the gap kind of an inverted V if you will in this location about midfoot. And then a decreased inclination angle and increased the talar declination angle with anterior breaking the Cyma line which is of course the line here with Chopart’s.

    [10:00] So, when you think about these patients, you have to think of the conservative and surgical options. There’s always continuum of care. You really want to be on the right side of this. So, this is an updated chart that kind of shows the stages themselves. And if you could summarize the entire talk into one slide, this would be that slide because it has stages on the left here and then you can see that it’s broken down the stage two into the pathological findings, the clinical findings, then ultimately the treatment options. And so let’s just take a look at this and certainly if anybody wants this, this was an article that was in the Podiatry Today and it came out in April this month. So, well last month I guess but it’s a good article. It’s talking about the biomechanical evaluation of flatfoot deformities, Doctor Richie with that. So, it’s important to consider the presurgical considerations. If any of these patients are going to do workup on you, you want to really consider the available range of motion. How much motion do they have and is it painful or not? Because that’s going to guide whether you’re doing a joint-sparing procedure or whether you’re ultimately progressing onto a fusion or other sort of in stage type of procedure. And you want to evaluate for the possibility of secondary changes. You also want to determine the planal dominance and this is something that’s really important in flatfoot surgery particularly in pediatrics but also to a degree in the adult acquired flatfoot deformity. It’s essentially which is the dominant plane because each surgical procedure is going to be most effective in a certain plane. So you want to come up with the right combination of procedures that are going to come together to give you the outcome that you want. You want to consider any related medical conditions, Marfan’s, Ehlers-Danlos for example. This is a patient who has ligamentous laxity. So you’re not necessarily going to try to do a tendon transfer or other procedure to address this because their soft tissues are just not adequate and up to the task. And you have to consider super structural deformities like the equinus deformity. Certainly prior to any surgical intervention you want to have demonstrated a failure of conservative options like bracing, UCBLs, orthotics, AFOs, and it’s important to document that. The goal of conservative care is to relieve the symptoms, to establish biomechanical control to allow for appropriate ambulation and to delay surgery as long as possible ultimately. You can get through this with activity modification as well as with use of medications. But again, there are pluses and minuses for each of this. Orthotic devices are a great tool for this and it’s helpful to think of orthotics like eyeglasses and this is how we present it to my patients. In the same way that eyeglasses improve your vision without changing without changing your eyes, orthotics improve the way your feet function without structurally changing you feet themselves. So they work when you’re wearing them. They don’t do any good in the door. And so it’s helpful to have these types of devices to really establish control over the hindfoot and really get the foot going the way you want it to biomechanically. And you can see here, this patient has a fairly significant valgus position. And then with the usual orthotics, we’re able to reduce this valgus into a much more rectus position. Certainly physical therapy is an option and it should be addressed to address the equinus deformity. Certainly in early stage one deformity is where it’s predominantly just a tenosynovitis that it’s very responsive to physical therapy. So it’s important, if you can it get early enough, that’s a good way to go. And then ultimately shoe modifications. So, when we progress all through that, obviously we’re a surgical specialty predominantly. And so eventually, you’re going to get to these patients that you are going to want to operate on. And so the question becomes when do you operate. Obviously, you want to operate when you have a failure of the conservative care. And you want to consider the social issues. Can the patient under go the surgery from a medical standpoint, from a social standpoint. Do they have the support structure necessary to recover? And I always tell my patients, you want to make sure that you can survive the surgery and then also survive the recovery. You really want to establish these things and really talk to your patients about this before you operate. Because once you’ve already operated and they’re in the room, postop day one and you’re trying to figure out now how they’re going to stay off of the foot for example. That’s not the time to have that conversation. And so, it’s important to have established and obtainable goals with surgery. And the goals should be to relieve pain, to prevent deformity progression, and to gain biomechanical control, a plantigrade foot that they can ambulant without pain. And so when you think about these, there are a variety of things you can do. And again, depending on what specifically is happening, the degree of equinus for example, planal dominance, you know, and often these are performed in stages ultimately. And I would encourage you to develop a systemic approach in it. And it can be whatever system you choose, but it helps you to think of it if you kind of go establish a flow. And so, for me, I start in the leg and I determine the degree and level of equinus deformity, and how we’re going to address that, and then I work into the hindfoot, and then into the forefoot. And that allows you to kind of unmask deformities as you progress and then ultimately address them. But again, I can’t hit on enough the idea of planal dominance. You definitely want to know that because the reason these things fail when they fail apart from non-use and non-compliance and things like that, it’s just the wrong procedure. And if it’s the wrong procedure it’s not going to work. And that’s where you really want to know what’s going to work for the deformity that you have. And so you want to select the appropriate combination of these types of procedures to address the pathology. This is just the picture of endoscopic gastrocnemius release.

    [15:02] This is a subtalar arthrodesis. Both of these can be very useful in the context of these types of deformities depending on what you find clinically. So, in terms of planal dominance, it is a compound deformity, any flatfoot deformity, a compound deformity, multiple planes. And so you have to establish whether the sagittal plane deformity which is the medial arch collapse. You can see this here. Sometimes that is the predominant plane of deformity. And ultimately there are multiple planes that are going to be involved. Transverse plane deformity, this too many toes sign that you can see here and it’s the forefoot abduction you commonly see in this progressive flatfoot deformity in patients, and then ultimately frontal plane deformity with the valgus position. So you really want to establish in each of these patients, in each foot, they may have it in both feet and have different planes of dominance in either side which are the ones you want to intervene on how are you going to address each level of deformity because there are essentially a variety of procedures that can address this. In the context of surgical procedures, there are soft tissue procedures and osseus procedure. We’re just going to cover them very, very briefly. Obviously, the equinus procedure is gastroc versus TAL and there are some different schools of thought on that. I tend to do more gastrocs because it is less likely to overlengthen, I don’t have to do it again, and I do them endoscopically. So it’s really, really quick and easy. We have very, very little risk for sural nerve injury. And people do well, and traditionally, they do have I a gastrocnemius equinus, it’s more common in these patients. Often, these patients present with an accessory navicular so Kidner procedure is not a bad option. This is the picture on one of the x-rays, it really don’t show up all that well, but this is the patient that had a Kidner and we did a subtalar arthrodesis as well to offload the medial side of the foot to reduce that frontal plane deformity in the hindfoot. Other options include the Lowman and Young and other procedures and you can look at a surgical textbook like Chang or McGlamry and they have lists and lists of these procedures. So, it’s just important to know that there are different procedures for different planes and you need to know which is which. Again, the equinus deformity, you know, I hit on enough just because it is so important. If you’re going to get one thing apart from that one big slide, check the equinus because if you don’t address it, you’re going to fail. It’s just not worth your time and the patient’s time to go through the process. The Silfverskiold test, quick and easy, it gives you an idea whether it’s a gastroc related equinus or whether it’s a triceps surae equinus and then ultimately whether you do a gastroc recession or a TAL. It’s just helpful to remember the anatomy as well. So, in a gastroc versus TAL, the evaluation of equinus forming, and this is a patient that we’re doing the Silfverskiold test. You can see it with the extended. There’s relative little dorsiflexion. However with the knee flexed, the dorsiflexion is adequate and that would suggest a gastroc equinus. And that person got an open gastroc recession. The arthrodesis, this is obviously a pediatric patient but I think it best demonstrates the value of these things and it does address subtalar joint instability, ultimately providing largely frontal plane correction. So it’s important to think of that in those terms for adult flatfoot, think frontal plane. You can use bioabsorbable metal, whatever the flavor of your choice is. There are pluses and minuses for both ultimately. There are a variety of different shapes and sizes and colors and things. But you can see that with the addition to the equinus, excuse me, with the addition of the arthrodesis, we have realigned the nearest angle here and have got the foot now swung back around kind of the way we wanted it to be. So, in terms of the osseous procedures for surgical reconstruction, there are a variety of osseous procedures predominantly starting in the calcaneus, as I told you, I work from the sort of the top and down. So that calcaneus is really the first bone of the foot that we have the opportunity to intervene on. And there are a variety of calcaneal osteotomies. The extra-articular, the anterior, the posterior, and each of them have a variety of different reasons to do them. Ultimately progressing forward into the medial column, fusions, things like that, the cotton, the miller, the hoke. And then ultimately, in patients with severe degenerative changes, arthrodesis is ultimately where you want to go with this. This is just acute osteotomy here. This gives you really great frontal plane correction as well. You can see how this realigns the ground reactive forces with the medial calcaneal slide osteotomy to bring everything back into alignment under the long axis of the leg. Alternatively, the Evans type osteotomy is performed along the sort of the anterior body the calcaneus provides more transverse plane deformity and that’s good if that’s your predominant area of deformity there. So here’s the, again, calcaneal osteotomy, this is just an MBCL medial slide and you can see as just move it over and then putting the screw across to stabilize it. And already they’re starting to see a little bit of an arch. You can kind of appreciate from just doing that. Addressing the equinus and moving the heel over a little bit. Medial column fusion, this is a great picture. I love this picture. It’s actually one of mine. This is one of the early ones that I didn’t address the equinus enough and this is what I’m telling you. If you don’t, it will come back to bite you.

    [20:02] This is a lady who had subtalar joint arthritis and she had a bit of an equinus but I was sloppy I guess and ultimately just did a TAL when she needed a gastroc. So her equnus when we came back. She was diabetic or progressed on to develop diabetes and ultimately her equinus deformity overpowered the midfoot and caused a charcot type midfoot collapse. And so this happens. We had a great stable fusion of subtalar joint but the midfoot just, we didn’t have the stability that we need there, certainly in the context of that equinus deformity. So it’s really, really important to address that and you need to establish the apex of the deformity, determine if there’s any hypermobility and again you really want to hit on this idea of the equinus deformity. If you can, you want to preserve the tibialis anterior tendon when you’re providing these medial column fusions. And I do this last because in the context of stabilizing the hindfoot, oftentimes, you’ll develop a supinatus deformity or forefoot varus or other kind of forefoot deformity that occurs after you brought the foot now back into position. So I do the forefoot and midfoot stuff last to figure out exactly how I want the tripod to be, where I want the first and fifth metatarsals to sit now that the heels in a position. Obviously, rear foot arthrodesis is kind of the final sort of gold standard. This is a patient who had fairly substantial subtalar joint arthritis, posterior tibial tendonitis. She had the break in the midfoot, and we ultimately progressed her to a triple subtalar with a TN and a CC fusion. And you can get great triplane correction for this. She does well. She walks without a limb and she’s happy as a clam. So, it’s not a bad procedure. It is something you want to have clear expectations with the patients though. So, when you have complications with this, predominantly, the primary reason, when I see this come in and somebody has an issue, it’s the wrong procedure was selected. So you can save yourself a lot of heartache by taking an extra minute and really thinking through the three dimensional deformity you have and how you’re going to correct it. There’s not a one size fits all. I remember, when I was a resident, I had attendings who always did whatever, everybody bunion got an Austin. And it’s just not that way. Patient’s feet are different, individual feet are different. So, you really need to tailor your approach based on what you’re seeing. You can get complications for under correction or over correction. You want to find the right balance point for that. And then ultimately, if you do have a complication, you want to manage it early with aggressive management and you really want to be honest with the patients. Communicate to them what’s happening and what your goals and expectations are both perioperatively and then in the context of a complication. So are there any questions? No questions. Okay. These are the sources. I have a good list of this if you want to read up on posterior tibial tendon dysfunction or equinus deformities or things like that.