Marie L Williams, DPM reviews the function and anatomy of the posterior tibialis tendon. Dr Williams also discusses how to diagnose and treat dysfunction of the tendon, reviewing both surgical and non-surgical options.
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Female Speaker: I’m actually going to bring a little bit of a subject that we see all the time, a posterior tibial tendon dysfunction. It’s a subject that is commonly misdiagnosed by our colleagues. Our internal medicine guys come in and even patients, I have a swollen ankle, painful ankle and it’s posterior tib tendon dysfunction. I want to just go over basically the etiology of the posterior tibial tendon dysfunction and what it is and implications of staging and determine the treatment plan. There’s both conservative and surgical plans. I think it’s important that we really look at the etiology which includes sometimes trauma. Someone who comes and twist their ankle, it may not be an ankle if they push off and their foot is in an everted position, in an abducted position, they may be straining the posterior tib tendon. There’s inflammatory diseases where you’ll actually see the tendon very swollen, the medial foot collapsed, and then you have degenerative disease of the tendon itself from a flatfoot. You have the tenosynovitis. Sometimes, you’ll actually see where patients says, “Listen, I’ve been to the other doctor or my orthopedist or my podiatrist and they’ve injected me here three times, five times, and it’s getting worst and I’m having more pain.” Well, just remember that local injections of corticosteroids can actually weaken the tendon and cause the tendon to become damaged which now you have a bigger problem. Overuse injuries are created by repetitive stress and that’s with any tendon, not just the posterior tibial tendon. There’s a lot of stuff where you’ll see there is a compression over the flexor retinaculum which I’ll show you. Many times, there’s a misdiagnosis, where it might be tarsal tunnel as opposed to posterior tibial tendon dysfunction. Or, how about varicosities which is what you see here. Varicosity is wrapped around the actual nerve and they have posterior tibial tendon dysfunction-like pain so you may end up having to deal with the tarsal tunnel problem and make sure that diagnosis is in. You might want to get nerve conduction studies and follow up with a nerve stim, what’s happening with the nerve function in the foot. General concepts basically, I’m not going to go over this and spend a lot of time. Anatomically, you know that there’s four stages that they’re critical for treatment. The tendon plays a major role in the gait cycle. It actually is something that causes the foot to invert and plantarflex as you push off. It helps to stabilize the arch so you don’t pronate. The acquired adult flatfoot is what we see generally. In addition to the pathology of the posterior tibial tendon, you have dysfunction which becomes progressive where you have now ligament is stretched on the medial ankle and foot. That’s why they have medial ankle pain. Anatomically, the tendon originates from the posterior aspect of the proximal tibia, the interosseous membrane and the fibula. It travels posteriorly to and around the medial mal through the flexor retinaculum superficially and deep to the deltoid ligament. You’ll see this a lot of times with post ankle fracture. A patient may have an ankle fracture and then six months later, the ankle is all healed but they have incredible intense pain medially because they have a large pull on the flexor retinaculum and disruption of the deep deltoid ligament. The insertion mainly inserts into the navicular tuberosity and plantarly at the first cuneiform in the basis of the metatarsals two through four, second cuneiform cuboid. It actually has a large expansion. This is just an anatomical picture. I’m not going to belabor that point. The blood supply is important because through age, sometimes you lose the blood supply to the tendon. The tendon becomes very thickened and you may even see striations or enthesopathy in the tendon itself because of the lack of blood flow and/or compression from the venous system. There are zones of hypervascularity and there’s been many articles written on it. Fry actually had 28 cadaver limbs injected with an Indian dye and showed that the zone of hypervascularity was 40 millimeters from the navicular and ended at 1.5 distal to the medial mal or an average of 14 millimeters. You will see that occasionally where you can palpate that area or zone of hypervascularity to the tendon and has an intense pain. This is where we commonly see the ruptures. It’s the main inverter of the foot and it locks the midtarsal joint as the Achilles tendon plantarflexes the foot at the level of the tarsus and it results in supination.
It’s antagonized by the peroneus brevis and it decelerates in internal rotation of the tibia and limits pronation of the foot, following a heel strike. Some of the other things that you have to see is that when you’re in early equinus, the tendon is firing more, you’ll end up having more pain due to the lack of function of the posterior tibial tendon or increased activity of the posterior tibial tendon with inability to compensate for that equinus. Pathomechanically you’ll see loss of inversion of the posterior tibial tendon where you’ll get inflammation and pain. It prevents locking of the midtarsal joint. You’ll see a collapse at the TN joint with flattening of the medial arch. And the peroneus brevis functions unopposed and so you’ll get eversion of the foot and abduction of the forefoot and calcaneal valgus. A lot of the residents, when I teach this, I always tell them that these are commonly board questions because they don’t think that the peroneus brevis is as important in stabilizing the foot as it is as an antagonist to the posterior tibial tendon. Why an orthotic can be very important because what you want to do is stabilize both the medial and lateral column. Here’s an example of just someone with a real calcaneal valgus with posterior tibial tendon dysfunction. Sometimes, you’ll see it bilateral. I see it many times unilateral, sometimes after trauma. It’s simple to diagnose really, we all see a lot of pain and swelling around the ankle. You'll have a generalized ankle weakness, collapse of the media longitudinal arch with and without unilateral flatfoot. Early on, the foot doesn’t flatten, but overtime, you’ll see that flattening. Clinically, you’ll see there's the heel raise test, the Hubscher maneuver or the Jack’s test and the Hintermann’s test, and there’s too many toes sign when you see it on radiograph or in stance. You ask the patient to stand up and lift up his or her heels off the ground, and normally the posterior tibial tendon will evert the foot and lock the heel and midtarsal joint and are unable to lift up very easily. With lack of inversion and weakness, the heel lift is very difficult and you can now see that with the posterior tibial tendon dysfunction. So they aren’t able to really lift up their heel and have lift up off their toes. You’ll see that as a difficulty for them. Here, this is a normal test where your young person is able to just raise up on the tips of their toes and raise their heel. In a person with a dysfunction, one might raise in the opposite side, the painful side will not. Again, the Jack test, this is important to see even how much the arch can resupinate to give you a better understanding of early posterior tibial tendon dysfunction. Hintermann also is known as the first metatarsal raise. The patient is put in weightbearing and the leg is passively rotated externally and the heel is passively inverted. I’m going to just show you a picture. Here you are holding the foot and putting it in neutral. From the back as well, the heel is actually now in neutral position as well. You’re able to actually get the foot in a neutral subtalar joint position. Very rarely, when they have a fixed posterior tibial tendon dysfunction, you’re really able to do that. When they stand up, you can see them from behind, too many toes sign. You have a complete fixed valgus of the foot. Radiographically, you may do an x-ray where you’ll see the whole lateral side of the foot is exposed even in a standing weightbearing. So that is something that really gives you a good indicator of how weak that posterior tibial tendon is, that they’re unable to supinate the foot and they’re now in a fixed fully pronated foot. The Helbing sign is very helpful to find out too if you have a lot of equinus. It’s been used for many years. You look at the back of the heel, and you’ll see how much that heel is everted and how much of the Achilles tendon contracts or lack contraction and the heel everts due to the weakness of the tendon itself. But it’s not pathognomonic of a posterior tibial tendon dysfunction but does help you to see how much lack of function the foot has. Now it gives you an indicator to start looking for these problems of equinus and/or posterior tibial problems. These are the too many toes sign and the Helbing sign where you can see three, four, and five laterally on the too many toes sign and you can see a little valgus of the heel with the Helbing sign. Radiographically, we’ll just run through this very quickly but the talocalcaneal angle is increased with the hindfoot and valgus and then talar is just pronated and that shows you subluxation or rotation of the talar head both medially and inferiorly.
From a lateral point of view you can see that the calcaneal inclination angle changes and decreases and you get a break in the talonavicular articulation, an anterior break in the cyma line and the decreased first metatarsal declination within the navicular cuneiform sag. These all come with the fact that the posterior tibial tendon is not functioning properly. MRI is not something that I do routinely unless I suspect a tear or chronicity of the tendon not being fixed mechanically. I tend to do a lot of treatment conservatively on a patient early posterior tibial tendon dysfunction by maintaining the function that tendon using a lot of strappings. I’m a kinesiology freak. I use kinesiology tape for these areas to help increase the vascular flow of the tendon and actually raise up the arch. But MRI is really important when you feel that there is some type of a tear. Normally, it’s a low signal intensity on the pulse segments. But when you see the tendon, there’s increased fluid around the tendon and it shows increased tenosynovitis of the tendon. There were 32 cases in this one article by Rosenberg where the actual MRI showed a 95% sensitivity with 100% specificity which meant that it was extremely very accurate in the diagnosis of a chronic posterior tibial tendon dysfunction and/or microscopic tears, longitudinal tears or inflammation. So MRI is good when you really do consider that there’s some greater pathology than the early onset of posterior tibial tendon dysfunction. Ultrasound, there’s a lot of information and literature out there. A lot of guys are using ultrasound to help diagnose. I am not an ultrasound expert but I put it in here for completeness sake because I believe that this is a great modality to help you diagnose this problem. Treatment stages, early on, you’re going to use cast immobilization, anti-inflammatory type of modalities as well as arch supports, and/or. As you move in, you might need more of an extensive orthotic to control the function of the foot to heel stabilize the rearfoot onto the forefoot to reduce some of the pain and sensitivity. Late stage, you might need even these column-type braces, surgery, possibly triple arthrodesis, Achilles tendon lengthening, and if necessary in late stage, you’re going to consider bracing. There’s the Richie brace out there and many other braces and/or surgery. So there’s a lot of ways of treating it. You can see here that I didn’t say we need to inject it, inject it, inject it because after a while that’s just not going to work. It’s only going to damage the tendon more and more. Stages, just quickly. The first stage is mild weakness in heel raise. There’s pain and swelling around the medial ankle. Patients always say that they have ankle pain. Radiographically, there’s no real sign of dysfunction. You can see on the MRI, you get an early tenosynovitis but no real deformity and the tendon is preserved with strain. Then once you move on, these are very simple treatment in the stage one. And actually, if you do this treatment well, it may not go on to any further deformity. What you end up seeing later on is that these early signs are not treated or they are treated for an ankle sprain or ankle pain and it’s really a dysfunction of the posterior tibial tendon. But if you can treat them early, immobilize them, give them an orthotic, you may not need to do decompression synovectomies or debridement. In stage two, the pain increases and they start to get very little relief of pain with rest. They get the flattening of the medial longitudinal arch. Radiographically, you start to see the forefoot becoming more abducted. The subtalar joint, the TN joint is subluxed. They’ll tell you that their arch is starting to collapse. That’s their most common complaint. But you’ll see a decrease in the arch height. I hope that represents well but you can see here where you’re starting to get some early change, where you're starting to get a little dip in the navicular cuneiform area. You don’t have a large decrease in the calcaneal inclination angle but the talus is starting to become declinated in here. The foot, you can start to see the unlocking of the talus onto the navicular in the anterior posterior view. Also, you start to get some irregular changes on MRI where you’ll get a fat-suppressed T2-weighted axial image and abnormality of the posterior tibial tendon which you can see there with the arrow. When you open it up, sometimes what you’ll start to see is these little striations in the tendon. The tendon looks pretty normal but what you then start to see is if the chronic pain hasn’t been resolved, you’ll start to see little tears, microscopic tears within the tendon longitudinally.
So if they have a posterior tibial tendon tear, it’s usually never a transverse tear, where it’s really ripped off the bone. You’ll start to see the striations within the tendon itself. That’s important because no matter how much conservative a treatment, if they start having these internal tears, you may need to surgically repair them, use maybe graft techniques or I personally use many different things, amniotic membranes, graft techniques, whatever it takes to help debride the necrotic tendon and I’ll reattach it if I have to. Remember, with stage two, you get a pes planovalgus deformity with longitudinal ruptures of the tendon. Hindfoot is very flexible. You may even have some minimal abduction. But you’re starting to see that you’re going to get some unlocking of the talus onto the navicular. That didn’t really present well but you can start to see little talar beaking, more collapse of the arch. You see here, as they stand, the medial side of the foot starts to collapse. They tell you that their ankle hurts and you know that it’s not the ankle joint at all. Especially when they can dorsiflex and plantarflex without any pain or sensitivity or inflammation and they’re very strong dorsiflexion and plantarflexion. Here you can see where the medial longitudinal arch from posterior to anterior has collapsed significantly and the posterior tibial tendon is not functioning or firing properly. Again here is another example of that. From behind, you can see the beginnings of too many toes sign and a Helbing sign posteriorly. Late stage, usually these young kids come in and they have had this all their lives. Now, that foot is really becoming more and more collapsed, less flexible, more fixed. You’ll see them where they’ll start to get varus rotation of the toes, pain in the medial longitudinal arch with adducted gait. I want to back up for a second. In this patient, what we did is a simple procedure of a subtalar arthroereisis. I like the subtalar arthroereisis because what it does is it allows the talus instead of plantar flexing, and actually holds that talus up and you now have a more neutral talocalcaneal angle. Then that’s all I do. If they have an equinus, I’ll do something for the tendo Achilles gastroc recession or lengthening, but more importantly, now I’m just realigning the subtalar joint, and I call my internal orthotic. Kidner is a good procedure for realigning that posterior tibial tendon. If the tendon slides more medialward instead of plantarward as it should. It’s a simple procedure. Unfortunately, I don’t have this here and sometimes you do it in combination with your bunion hammertoe deformities. I actually have a case and I’m sorry that I can’t find it. I looked for days for this. I did a Kidner procedure in a girl, she was 10 years old. I did that simple procedure where we drilled holes from the top of the navicular to the bottom and then you brought the threads up. We probably only have Ethibond sutures. We didn’t have any kind of fancy sutures and we tied them on the top of the foot. I saw here when she was 22, so now 12 years later. That foot arch was unbelievable. It was stable, it was nonpainful. She came in for an ingrown toenail. Then I saw her again when she was 28. I’m aging myself a little bit but I saw her when she was 28. And that arch didn’t change and I took x-ray serially to show you. For me, what it did is it had taught me something that it’s a very good procedure and usually an adjunct with other procedures. So, I just thought I would share that with you. But it’s a good procedure. Here it is, the Kidner procedure with the tendon transfer, there’s many ways of fixating these and that’s going to be up to you and how you like to do it. You can use bone anchors but make sure that tendon is put in a more plantarward, plantar grade position to hold up the talonavicular area and that will help a lot. So here it is being in place. I’m going to go a little quicker because we’re running out of time and I have a bunch of things to tell you. So remember that there’s orthotics out there. I do not do a flexor digitorum longus transfer anymore because I believe that there’s enough biologic tissue out there that you don’t have to destroy other tendons. There’s enough literature that states that these biologics are so strong and powerful that you could replace the tissue with that. But calcaneal osteotomies and lateral calcaneal osteotomies and lengthening can be very important in stage two and three. Longstanding deformity is stage three where you now become more and more fixed and you have inability to really raise the heel off the ground. You can imagine that if they can’t push off and raise the heel to the ground, now everything starts to change biomechanically. When they push off, they abduct. When they abduct, they put a lot of pressure on the medial knee.
They may even come in with medial knee pain or they come in with hip pain. You don’t know how many people come in and say my hip is killing me, I don’t know what’s wrong, I have to go see their orthopedist or whatever and then it really starts from the foot. So just be aware of that because everything in that chain changes because of the way the foot is adducting or pronating. Radiographically, you’ve seen this where you have an increased forefoot abduction, minimal arch height, orthotic changes of the subtalar joint. The MRI, there’s a partial or there may be a complete rupture of the tendon. There’s definitely striations in the tendon and that’s very painful. And stage three, now you have your mix, more of your fixed plantar grade pes planovalgus deformity with valgus of the hindfoot and abduction of the forefoot. And now you have subluxations that are very classic where they look like they’re walking on the medial side of their foot. And then here’s a young kid who’s very flexible, stage three, couldn’t run. You ask him to run down the hallway in your office and it was really sad because these kids can’t run. So this is the foot radiographically. What you see more in the anterior posterior view is how much of the talus is uncovered in relationship to the navicular and there’s so much collapse in the medial longitudinal arch. And what I did is a subtalar arthroereisis. Now, this lecture isn’t to promote subtalar arthroereisis but it just shows the power of it. If you can protect the talus from plantar flexing down and everting onto the forefoot or rearfoot to the calcaneus, you can get a significant change in the way the foot functions. Triple arthrodesis might be necessary. I don’t triple arthrodesis in stage three. I wait until we’re in a fixed stage four but there’s a good example of another type of procedure. We’ll do calcaneal osteotomy sometimes to realign the foot with a Kidner, modified Kidner. So much of what Dr. Caleb said, you have to think and understand the etiology and pathology of the problem. Is it a transverse plane problem, is it a frontal plane problem that’s it the posterior tibial tendon dysfunction that’s creating all these before you’re going to extensive surgical reconstruction. Achilles tendon lengthenings may be necessary. There’s a school of thought that you should always be doing tendo Achilles lengthenings. I’m not one of that school but I do it when necessary. Subtalar fusion is important if you have severe osteoarthritis to the joint. I never fuse kids if I can keep them moving and I can reconstruct. I think it’s better. When you get an endstage/stage four progressive disease with flattening of the foot and it’s degenerative, refusion will be required. When you look at it from a stage four point of view, you have the deltoid ligament is completely stretched and incompetent, you’re basically walking on the medial side of the foot. It does not resupinate. You cannot push off with the toes. The gait is significantly abducted and you have other problems due to with the compensation. So you can see here, stage four, really there’s not much you can do with that. It’s not like an orthotic is really going to help that. You can see the toes. I love looking at the toes when you see that. You get the significant adductovarus of the toes because the lateral column is trying so hard to resupinate that foot and it’s not happening. Here again valgus of the heel and the medial side of the foot. If you’re walking on that, you’re not running. You could use frames, you can do all kinds of things. If you get an intrasubstance tear, just a quick thing, actually, I was going to skip this but I’ll just tell you that. I use acellular dermis to repair those tendons really simply. You’ll see striations in the tendons and I will repair those striations, put in acellular dermis and it’s a really good technique just for a simple tendon problem, not a complete foot reconstruction for the posterior tib tendon dysfunction. But that’s a simple procedure to actually correct just longitudinal tears.