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Board Review Surgery

Current Concepts in the Treatment of Digital Deformity

Steve A Brigido, DPM

Steve Brigido, DPM discusses the etiologies to hammertoe deformities and identifies the common challenges we face in performing hammertoe repair surgeries. By reviewing several different fixation techniques including K-wire, Barbed fixation, Nitinol fixation and a two-part system, Dr Brigido further identifies advantages and disadvantages to each system and offers pearls to improve outcomes.

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Goals and Objectives
  1. Review biomechanical etiologies to common digital deformities
  2. Identify complications with K-wire fixation
  3. Describe advantages and disadvantages of alternative fixation techniques
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  • CPME (Credits: 0.5)

    PRESENT eLearning Systems, LLC is approved by the Council on Podiatric Medical Education as a provider of continuing education in podiatric medicine.

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

  • Author
  • Steve A Brigido, DPM

    Director, Fellowship for Foot and Ankle Reconstruction Coordinated Health
    Bethlehem, PA

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    Steve A Brigido has disclosed to be a consultant/advisor for Stryker, Bacterin International and Wright Medical. And also has disclosed receiving consulting fees from BMTI and Nextremity Solutions.

  • Lecture Transcript
  • Male Speaker: Let me talk to you a little bit about kind of some of the newer aspects of the treatment of digital deformity. Certainly, I think we can all attest that this is a problem that treating digital deformities is certainly one of the more frustrating aspects of the foot and ankle surgeon’s practice. Certainly, we’ve all had situations where there patients we thought would have a tremendous outcome come in and they have toes that swell or misshapen. Various different conditions where the patient is unsatisfied after the repair. And today, what we hope to do is just talk a little bit about the way that we approach digital repair and kind of the newer techniques that we’re utilizing to try to get a more consistent outcome. Hammertoes or deformities of the digits certainly come in many varieties. We know that they basically can be broken down in two groups, congenital or acquired. And with that, the neuromuscular disorder is certainly an aspect which is a whole separate animal when you consider treatment regimens. But for the most part, most people that have digital deformities are those that have some biomechanical dysfunction. I think for the most part, at least in our clinic, I would say 90 to 95% of the digits that walk into our office that have some sort of pathology associated with them are because of faulty biomechanics. And this is certainly the main source of the problem that we’re trying to approach. I’m just going to briefly go through the types of digital deformities just as a refresher before we get into the heart of the talk, which is how do we fix these problems that can become very frustrating for not only the patient but for the surgeon. Certainly, the mallet toe is the first type of digital deformity that we see and this is certainly defined by distal interphalangeal joint flexion. I’m getting some feedback, Allen. Is it the microphone or the second microphone? No. When you have distal interphalangeal joint contraction at the DIP joint, we want to certainly first look at our distal collateral ligaments and potentially sometimes people have talked about distal arthroplasty is the way to treat this common condition. This is not the type of toe that we’re going to be focusing about this morning. We’re going to be more focused on the claw toe and the traditional hammertoe when we talk about the approaches that we’re utilizing to treat these disorders. The claw toe is defined as DIP flexion, PIP flexion and MTP extension. Certainly something that we see much more traditionally in our office. When we think about the claw toe, we certainly think about whether it’s been MTP release or metatarsal shortening osteotomy. We think about interphalangeal joint arthrodesis. We think about collateral release and/or arthroplasty. And these were things that certainly come in to our office on a routine basis and it’s certainly something we’ve described and talked about at ad nauseam throughout our careers. And then finally, the third type of digital deformity that is probably the most common is that hammertoe deformity. When you think about the number of hammertoe disorders that are done a year, we’ve got roughly 533,000 digital surgeries done a year to correct hammertoe and claw toe and I guess you would include mallet toes in that. And there are 1.2 million diagnosed but untreated hammertoes in the United States at any given time. And, roughly about 30 to 60 million sufferers. And I think we’ve all had patients in our office that have come in and said, “Well, jeez, I had family member X, Y and Z that came in and had a really bad experience. So even though this toe is killing me, I don’t want to treat it.” And, because of that, we’ve got to find better and more predictable solutions to treating these digital deformities. The classic hammertoe is defined as MTP extension, PIP flexion and DIP extension. When we think about the three types of hammertoes, we think about the flexor stabilization, the flexor substitution as well as the extensor substitution. The flexor stabilization is certainly one of the more common digital deformities that we see. We find it often in the pronated foot, actually we find it only for the most part in the pronated foot when this is a condition where the flexor digitorum longus will gain mechanical advantage over the interossei muscles. It’s commonly found in the stance phase of gait and the hallmark sign is that adductovarus fourth and fifth toe. Certainly we all know people that have these and many of them are unpainful but many of them that can become painful as they develop some arthrosis and also develop some interdigital skin lesions associated with that. They can become quite uncomfortable. The flexor substitution is almost the same type of pathomechanical dysfunction.

    [05:02]

    But we see it not on the pronated foot, we see it more in the supinated foot. This is when the flexor digitorum longus gains mechanical advantage over the interossei muscle. It’s also found in the stance phase of gait but because of the supinated foot, you’re going to see a straight digital contracture. The toes are going to have a significant flexion. The FDL is going to be the main source of the problem. That has to be considered when you’re certainly addressing it. And the final type of hammertoe deformity is the extensor substitution. This is probably what people, when they consider what a hammertoe is especially in the general public, probably consider most to be your traditional “hammertoe deformity”. We see these more commonly in the swing phase of gait. And this occurs when the extensor digitorum longus will gain mechanical advantage over the lumbricals. And what we’ll see typically when the patient is going from push off and the heel strike through the second cycle of the gait pattern, you can see the bowstring of extensor tendons and you’re going to see a relatively straight contracture with the toes and the metatarsophalangeal joints dislocating dorsally. So when you think about our treatment challenges to these, we’ve all certainly have treated hammertoes I would guess at one point in time with Kirschner wires. I think that’s still considered to be the gold standard treatment for hammertoe repair. And we’ve all used probably at one point in time or have started to utilize some of the newer technology that’s out there. When we think about treatment challenges, we want to think about a couple different things. And we talk to our fellows about treating hammertoes and how we go about the algorithm in our heads is that what approach we’re going to take to treat this. We have to think about four or five main things. The first is poor bony purchase. What is the bone quality like, does that Kirschner wire that occasionally needs to reach the metatarsophalangeal joint and certainly will cross the distal interphalangeal joint. This is basic splintage, so does the bone quality adequate enough to maintain splintage and maintain the goal of that what wire is trying to do without sliding, migrating or bending. Did the designs of the implants maintain the ability for bony purchase to occur without causing a secondary problem? Kirschner wires certainly give us a lack of compressor force. Again, Kirschner wires, typically AO splintage, it’s basically an internal cast to the toe. It’s meant to hold the toe in position so that the toe can heal the proper way. And then once it’s healed, we can remove that splintage and allow the toe to be in rectus alignment. But because of that, we’re not able to get good bony compression out of the interphalangeal joint if we’re going to do an arthrodesis. Because of the Kirschner wire and because of the way that bone heals, remember bone cells will migrate away from the pin not because it’s metal but because the solidarity of the metal does not look like trabecular bone. So because it does not recognize a trabecular pattern, it’s going to migrate away from that pin and that’s when it’s going to allow those pins to spin and sometimes piston. The more pin spins and pistons, the better chance you have for skin irritation in there, therefore, you’re going to get a better opportunity for skin infection. When you think of insertion in similar issues, these are things that K wires can certainly become frustrating. I don’t think there’s a surgeon in the room where we’ve not had to throw a wire two or three times to get in the exact position that we wanted in. We’re putting interfenestrations into the bone. We’re crossing the joint several times. This can be a frustrating challenge because digits are small. Again, the sizes are unpredictable. If you’ve ever tried to map on a CT scan the sizes of what the phalanx and metatarsal head looks like, there’s a wide variety of what our patients walk into the room with when they see us. You can have patients that are very large and have small phalanges. You can have patients that are very small that have very large phalanges. It’s difficult to map and understand. And because of that, when we’re utilizing Kirschner wires to fix these problems, they’re quite frustrating to deal with. Finally, we think about the removal of Kirschner wires and what kind of stress that is, even though we all realize that it’s relatively easy to do. And for the most part, the patients go, “Oh, that’s it”, something that does give our patients anxiety. And also, once you remove that splintage, you’re removing that internal cast which was helping to maintain the alignment of the digit. Again, if we can have an opportunity where we can keep something inside of the toe as opposed to through the toe that we removed, we may have, again, an opportunity for more predictable outcome. So, when we talk to our fellows about how we’re going to treat these patients, we want to have something that will give us these four criteria for successful outcome. We want to have something that’s going to give us good solid bony purchase, that’s going to give us something that’s got good compressibility. We wanted to be able to align and lock. And we want to be able to reverse it, undo it and adjust it if we need to. I think all four of these tendons, none of them are more important than the others. But together, they can give us a nice algorithm for a nice predictive solution for these digital repairs.

    [10:03]

    So the longstanding question is, is do we go through digital arthroplasty or do we do an arthrodesis. I would guess if we were to pull the room, there’s probably about 50% of us that like to do arthrodesis and there are probably about 50% of us that like to do arthroplasty. We’re all trained differently. And there’s certainly no right or wrong answer. I would tell you that we’re leaning more towards arthrodesis, although I was trained to do more arthroplasty in a training program. I think arthrodesis tend to give us a little bit more predictable outcome. I think when you look at arthroplasty, we think of the most common complications associated with arthroplasty. When we remove the head of that phalanx, we’ve got an opportunity to lose the toe purchase associated with the ground. It gives us the ability to get a recurrent digital deformity because of that space. If that space does not scar adequately, what will happen is that that distal segment of the toe can dorsiflex, it can create a triplane deformity. It can shorten the toe significantly. It can allow for a flail toe. And certainly scar pain is something that we’ve all probably dealt with at one point in time. You grab that proximal interphalangeal joint with your arthroplasty deformities, squeeze it from medial to lateral and not only do you feel a nice nodular scar tissue in there, but the patient is uncomfortable. And we’ve all tried to utilize things like dexamethasone and some of the other modalities that diminish the scarring of the digit. But it’s something that when the scar occurs, the scar needs to be removed. Sometimes the toe needs to be revised. And sometimes you just say, “Okay, this is the situation we’re going to have to deal with.” As the scar matures, it will potentially get better and better. So when we think about digital arthrodesis, we’re taking the middle phalanx, we’re taking the proximal phalanx and we’re going to try to find a way to get these two bones to fuse together and create a situation where the toe is in great alignment. Well, certainly pin fixation, as I talked about earlier, certainly would probably considered to be the most commonly used or, for lack of better terms, the gold standard for hammertoe repair. But again, as I talked about earlier, it’s challenging way to match the anatomy. The pin is always going to cross that distal interphalangeal joint which has a small articular surface area to begin with. So if you put a 45, or a 62 Kirschner wire through that, you’re going to get a situation where that joint can arthorse and become stiff and uncomfortable at a time. There’s no compressor force because it is AO splintage. And these pins will often loosen. When we think about the complication, this is a lady we fixed probably 8 or 10 months ago who was walking up her stairs and she, for whatever reason, didn’t have a surgical shoe on and the tip of the toe hit the edge of the stair and actually lifted her foot up to get up onto the stair, the pin bend straight down at about 40 degrees. And you can see we’ve got a situation where that pin is not going to come out easy. So, it’s happened. It happens all the time. Ultimately, we talk to the patients and we say, “If you’re going to have a pin in your toe, you’ve got to take care because if you bend the pin, you’re going to have an opportunity to have a bent toe and when that pin comes out and we’ve got to take it out immediately and oftentimes, it’s difficult to reinsert a pin if it’s not been in for the appropriate amount of time.” So, these are all things that we have to consider when we’re treating the patient and part of the patient is their compliance level and their personality is certainly part of the picture. This is a device that we certainly utilize in our clinic which has a barb fixation at the distal segment which is the intended purpose of this is to grab the middle phalanx and then we’ve got this threaded portion that will sit into the proximal phalanx. And it comes in an angled and a straight version. What we like about the implant and we’ve used it many, many times is that, the proximal phalangeal component will bite wonderfully. The threaded portion will actually sit into the proximal phalanx and the canal of the phalanx and really give you a good purchase and good anatomic alignment. We’ve had troubles with the distal segment in terms of its ability to purchase the medullary bone of the middle phalanx. Patients have done very, very well with it but we’ve also had times where the patients have had problems where the toe is dislocated a little bit. Again, when we’re looking at the patient, the goal of this is, is not to say that this is an implant, they can serve your purposes. But again, you have to look at the patient’s overall picture and say, “Okay, what kind of bone quality does he and she have, what is the size of the phalanx, how will those distal barbs fit when we’re doing our preoperative planning.” And if you have an ability to maybe tailor the particular implant they’re going to use for the particular patient, you’re going to be able to kind of avoid these problems that we cause when she came into the office a week or two later and the toe had a little bit of a dislocation. Now, to correct this, we can either pop this back into place or as we did, we decided to open it up and make sure that the toe was completely realigned anatomically so we didn’t have a situation where we went onto malunion or nonunion.

    [15:04]

    This is an example of a nitinol fixation device which we use quite often in our facility. It’s a product that has, again, a proximal and a distal segment to it. This is the proximal segment. This is the distal segment. The proximal segment, you can see as it inserts, it’s very narrow. But because nitinol, it comes from a block of titanium but it’s a metal that can be trained because of the properties of the metal, you can utilize body temperature. You can utilize electrostatic charges in many different things to stimulate this metal too. They expand and contract, or change shape. So, the benefits of it are, when this product warms up to body temperature, you’re going to be able to have this very narrow segment expand widely. And because of that, you’re going to get good bony purchase. With that being said, you’re utilizing the patient’s body temperature to stimulate that metal to react. You do have to be a little bit focused on your time constraints. You have to make sure that when you’re ready to insert it, you’re going to insert it at the appropriate time because if it does warm up too much, it’s going to expand. Not a big deal because they do come frozen and it’s something that typically you’ll have a little play in the metal. So if it does start to expand, it will fit in the canal very well. Some of the drawbacks to it are the fact that it can slide down the canal, and I’ll show you a picture of that canal slide in a second. Now, we’ve been able to rectify that because what we’ll do is when we’re inserting these, we’ll put a Kirschner wire from dorsal to plantar in the proximal phalanx right in this area. So that way, when we’re going to meet the two bones and do our arthrodesis to get our compression, this implant cannot rock back in the canal. You can see here, this is an example of what we call a proximal canal slide. Again, when this was inserted now, what we’ll do is when the proximal phalanx is seated, we’ll insert a Kirschner wire from dorsal to plantar into this area. So that way, when you try to meet the two surfaces, this can’t push back. And then what we do is we take the Kirschner wire out and that will prevent that from sliding and allow the toes to meet. Again, when we’re thinking about the overall picture, if you have a noncompliant patient, if you knew you need to get this thing out, if the toe has any fusion around it, you have to chisel it away to take it out in one piece. You’re not going to be able to get this out in two pieces, so it does make it a little bit more challenging to remove in certain situations but in others, it comes out quite easy. And then finally, the implant that we tend to use a little bit more commonly in our practice is this two-piece component. What we like about the two-piece component is that it does have a little bit more adjustability and we can reverse it if we need to. Some of the challenges that we’ve associated with are the fact that, again, the medullary canals are very different in the distal or the middle phalanx and the proximal phalanx, and you want to make sure that you size this appropriately. What it is, is, again, it’s an extra implant and it’s a two-piece component. You can see it’s got a middle phalangeal component and it’s got a proximal phalangeal component. The middle phalangeal component will have a stem on it as you see here. And what will happen is, is you’re going to sit this into the middle phalanx. You’re going to center it onto the phalanx, after you debride your articular surface. And then you’re going to sit this in the central portion of the medullary canal of the proximal phalanx. And you simply will mate the male end with the female end. And you can see it’s got three little ratchet click marks there. So as long as it’s seated at the very least with one click mark, the implant is stable. So it gives, again, the opportunity to tailor to the patient a little bit more to match their size and anatomic needs. The surgical technique for implant and all of these devices is very, very similar. So we’re going to go and we’re going to do our typical digital exposure. We’ll alternate depending on a patient. We’ll do an elliptical incision at the PIP joint or if we need to work at the MTP level, we’ll do a linear incision. We’ll go and release our collateral ligaments and then we’re going to take and utilize either a conical rimmer or we’ll utilize a sagittal saw and we’ll just do a flat top resection of articular surface. We’re going to, again, rim our proximal canal, utilizing a step rimmer that comes with the system. With that, you want to make sure that you’re centered in the phalangeal head. You want to make sure that you’re straight. You want to follow the long axis of the phalanx. And you want to do the same thing for the middle phalanx. You want to utilize a step rimmer. You want to make sure that you’re centered. You want to be basically a bull’s eye. And if you need to touch up the phalangeal head or the middle phalanx, again, you can go back, utilize the rimmers or if you want to utilize a rongeur to make sure things are nice and smooth so that you can mate the two surfaces precisely. Again, this is an example of our middle phalanx being prepared.

    [20:02]

    Now we’ve got our prepared joint that’s ready for arthrodesis. Utilizing the driver and we’re going to take our proximal component first and we’re going to basically utilizing a standard AO driving technique. We’re going to advance the phalangeal component into the canal. We want to make sure that we’re following the long axis of the phalanx. We want to make sure that we’re centered. And the driver is going to have two black lines on the driver that you can’t see here. But they need to be facing 12 o’clock and 6 o’clock. If they’re facing any other timeframe, then what will happen is, is that your implant because it does have about a 10-degree flexion to it that will make your toe a little crooked in that orientation. So as long as you’re at 12 o’clock and 6 o’clock with your black lines, that’s going to show that you’re going to have a toe that has 10 degrees of flexion in the normal anatomic sagittal plane. We’re going to insert a distal stem the same way. Again, you want to make sure that the distal stem is fully seated so that the base of the implant is [indecipherable] [20:58] with the subchondral plate. And you’re going to see you’ve got your stem visible. This is when you’re going to mate your distal segment with your proximal segment. As you’re mating the two segments, you’re going to hear an audible and you’re going to feel a palpable click and you can compress those three clicks as much as you can to get the toe surfaces together. Some patients who are very large will only need one click. Sometimes patients will need all three. I would say that most of our patients will utilize all three clicks. It will be well seated and nice and stable. And once the stems are mated, like I said, you’ll feel the click. And if you need to adjust it or if you don’t like to position the toe, you twist the toe at the IP joint 20 degrees. And if you twist it, it will unseat the ratchet and then you can take it out and you can reposition the digital hardware if you need to. If you have a situation where the patient were to hypothetically go into a malunion, you could do exposure joint, you can resect any bone that’s growing. And you can again go in and twist it 20 degrees and unseat the surfaces and you’ll be able to displace your implant. This is a case study of a 54-year-old female where she obviously had some hallux deformity and she had some arthrosis and she had two, three and four digital hammertoes. We can see here, we did a cheilectomy with an Akin and we’re able to correct the digits. Again, you can see here that in this instance, you can see there’s a little space where you can see a little bit of a stem. I think she had two clicks on the ratchet here. This one was fully seated where all three were able to compress down. And again, this one, you can see a little bit of the stem there had two clicks as well. Again, you do not have to make the male end fully seat with the female end. As long as you get one click, the implant has the same amount of stability that it has with three. So you can tailor the patient’s anatomy to it a little bit and find what works best for the particular problem you’re correcting. So that’s what I have for digital repair. Thank you guys for your time. Appreciate it. Good morning.