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Board Review Foot Conditions

Hammer Toe - Implant or Not

Michael Trepal, DPM

Michael Trepal, DPM compares traditional fixation with implants for lesser toe deformity repair. Dr Trepal also reviews multiple studies comparing the effectiveness of both.

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Goals and Objectives
  1. Identify types of lesser toe deformities
  2. Describe the use of traditional fixation for hammertoe surgery
  3. Describe the use of implants for hammertoe surgery
  4. Compare traditional fixation vs. implants for hammertoe surgery
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  • CPME (Credits: 0.5)

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

  • Author
  • Michael Trepal, DPM

    Vice President for Academic Affairs
    Dean and Professor
    Department of Surgery
    New York College of Podiatric Medicine
    New York, NY

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  • Lecture Transcript
  • Male Speaker: We’re going to start off this morning with a talk on Hammer Toe, Implant or Not? That is the question. I mentioned before, I served as a consultant for Vilex. As we’re trying to make decisions, we try to the best that we can to utilize good evidence of what’s out there. Unfortunately, for many of what many things that we do, particularly in this discipline, there's not a lot of good RCTs out there. There’s a couple of studies that we can relate to that we can cite, but for the most part, most of this is done based upon clinical acumen, clinical impressions, certainly the skill of the surgeon and that still matters. Also, what the evidence shows and that is important, but surgical skills, surgical decision making is still an important aspect to you. It’s confusing. We have conflicting papers, conflicting comments, conflicting ideas, and when the rubber reach the road, we have to really face with a patient, we have to make a determination, many times faced with conflicting evidence. When you look at things all too often in this discipline, like the blind man and the elephant. If you don’t open your eyes and take the blinders off, one person feeling the trunk thinks it's a rope, and one person feeling the leg thinks it’s a tree stump, and feeling the ears is a leaf. Everyone with the same thing thinks it’s something different until they open up their eyes and take a look. Clearly, there’s more than one way to skin a cat and dealing with digital surgery. Two ways can be right. A lot of this all comes down to doctor-patient. I found doctor-patient interaction, if the patient understands what they’re getting and understands the procedures and what they’re going to come out, they seem to do better. It’s really important here that when you’re walking down any surgery, that we have a good doctor-patient discussion of what’s going to be done, what the reasonable expectations are, what reasonable things can go wrong, because nobody gets 100% results. We’re faced with hammer digits syndrome. Hammer toes come in all shapes or sizes. Not all deformity is the same. We differentiate hammer toe, claw toe, mallet toe. Like I said yesterday we’re taking about the plantar plate and the metatarsal deformities is that these are all, from one sense or another, 95% of the time, muscle imbalances. You can have structural problems. You can have hypertrophic condyles. You can have exostoses in the digits. You can have anatomical variance. But for the most part, when you’re getting contractures at the MTPJ, the PIPJ, the DIPJ, and various combinations and permutations, it’s all to some extent of a muscle imbalance. Sometimes it’s identifiable neurologic disease of what the underlying cause is, and sometimes it’s not so clinically evident. Again, bottom line is that there is a muscle imbalance here. There is lots of different structures that cross that MTPJ, PIPJ and the DIPJ. The digital apparatus is a very complex entity, much more complex in many cases than the knee or the ankle. The amount of tendons, you’ve got three joints there, is mind boggling. When you get these out of balance or loss of power surrounding it, extensors, flexors, intrinsics all get out of kilt of ending up with the deformities. We want to treat them before you get to this point. These, for lack of a better term, endstage hammer toes are exceedingly more difficult to treat. If you can intervene prior to the patient presenting with this type of deformities, I think we’ve done a good thing. Now, a classic approach to doing hammer toe is the post arthroplasty. The procedure has been around probably 100 years now or close to it, with simple resection of the head of the proximal phalanx, repair the extensor tendon. As I said, it’s been around a long time. Any surgeon in this room, I’m sure, has done hundreds if not thousands of these in your career. It could be augmented with flexor tendon transfers to ensure stability, releasing of the extensor hood. It can be augmented with Kirschner wire fixation to increase stability. But at the end of the day, still when all is said and done, you get complications. As I said in one of my prior talks, looking at the sesamoids that I resect, that big hallux varus that [indecipherable] [04:48], that patient would like their sesamoids back. This patient would do anything to get their hammer toe back, what they started from. You don’t want this type of thing.

    [05:00]

    The instability that was occurring at those joints was accentuated by resectional arthroplasty. Surgeon did not impart new stability to it, and the end result here is what you see. In order to prevent those type of things, we’ve developed different ways to counteract it. Necessity is the mother of invention. Kirschner wire has been around for a long time. They’re relatively inexpensive, relatively easy to use, to add to stability, let that resectional area fibrose in. Problems with K-wires is they’re not immune from infection rates. One study, 18%, I think that’s a bit, certainly in my experience, so that 18%. Certainly in the literature is as much as 18% pin tract infection rate. If you’re utilizing it to secure an IP fusion, 20%, nonunion is also one out of five will go on to a nonunion. Whether or not that nonunion is clinically significant, we’ll address them in a little bit later. Of course, they can violate the DIPJ. If you retrograde into the metatarsal head, they violate the metatarsophalangeal joint. They’re not without their own drawbacks. If patient walks on them, as they frequently do, you end up with a situation like this. It’s a great lever on there and they can break in there and be left with a retained foreign body within the metatarsal head. Even if it doesn’t break, extracting this K-wire when it’s bent like that is not a pleasant experience for the patient and it’s not a pleasant experience for the surgeon, I can assure you. Digital arthrodesis have again, to impart stability there and prevent recurrent deformity, have been around a long time too, again, over 100 years. Many different combinations permutations have been described, each one with slight variation. But at the end of the day, it’s looking to make a stable construct of that PIPJ or the DIPJ or both. The indications, as we’ve been saying over and over again, is where you have compromise of the extrinsic function or instability of the metatarsophalangeal joint, where simple resectional arthroplasty is going to end up with recurrent deformity. The most common way that most we’ll do, again, there are variations, is a simple end-to-end resect the cartilage from the phalangeal head from the base of the adjacent phalanx, put those two pieces together, sprinkle holy water on them and hope that they unite. Usually, it needs to be some type of fixation, and the most common is with K-wire. The traditional fixation methods have been with Kirschner wires, as mentioned, stainless steel wire, people do staples, absorbable pins, external splinting, wrapping the toe with Coflex, or even bone screws. Absorbable pins have the advantage of absorbable technology. They do their job and then they go away, nothing to extract. Some of the PLA models are associated with a sterile abscess due to degradation products of it. PDS pin, that’s been around for probably almost 20 years now. It goes away. It’s not associated with much tissue reaction, but it’s very flexible as you can see here and can end up not being as firm splint as a metallic more rigid pin. In terms of implants, you like choices? Baskin and Robbins has how many different flavors? We got a lot of flavors available [indecipherable] [08:48] implants. Take your choice. Okay, is one better than the other? Well, clearly not everything is equal. As I said before in the beginning, there’s more than one way to skin a cat here, but you have choices. I really liked the comments I mentioned it yesterday that Tim Kilmartin made in his lecture yesterday, that he loves endstage hallux rigidus because it limits the options. Okay. You’re down, you don’t have a lot of choices. It limits options. When you have a lot of options, it makes it more confounding for the patient and of course, obviously, for the surgeon. Screw fixation, compression screws are around, available. They cross the joint, exert an interfract compression of the construct. Add a little bit more cost than say a Kirschner wire. Remember, the medullary canal and the proximal phalange is not really good dense bone that can be grabbed on there in the thread. Engagement of the threads into the medullary bone can be tricky.

    [10:01]

    These things can back out. They can recede out of there again because of the inability of the medullary bone or the phalange to really grasp it good. Technique of it is not terribly complex. It’s the standard technique like you would insert any compression screw. You drill, insert the screw, compress it down, and again, hope for the best. They can be effective and hold it. This is one option that you have for doing a digital arthrodesis. Dynamic implants, which respond to tissue temperatures and can change configuration and shape the nitinol implants either by spring loading or by transformation of the metallic structure of the implant will exert some compression there as well. We have two component implants that are also available. This one component, male in one phalange, female component in the other phalange, snap them together, twist it. These have certain advantages that if you don’t like the position, you can untwist it, unsnap it and reset it. Here, we’re all putting in a two component, one is drilled into the proximal phalange, one into the distal phalange, and you can see the end result there. Single component devices are also available. The single component are threaded. They can be screwed in. They are inserted into one canal and then snapped into the adjacent. Problem with single component is if you don’t like the configuration, if you don’t like the way it sits, you’re pretty much stuck in not all, but in many cases, you’re stuck with what it is. You can’t unscrew it and take it out. Here, we see the single components. With all those options, what are we doing? The literature is not great. You will see, most of these are level four studies, retrospective. Many of them are industry funded. They are not randomized for sure. Most of, I’m looking at it retrospectively. Here’s one looking at a level four study, retrospective review, powered fairly decently, 252 hammer toe repairs, 63 with intermedullary implant, 190 with the standard complications. Again, the endpoint here was to look at complications. We always have to look at what the endpoint of what the study is. In terms of malunion or infection, there was 14 with the implant, 37 with the K-wire. Remember, there were many more K-wires used to the implants, so you just can’t look at that and say, “Oh my god, three times with the K-wire complication.” Well, you have three-time the patients into the study. Another one done by Witt and Chris Hyer, retrospective review of seven implants, again, not particularly high powered in three patients, again, not a lot of volume here, looked at them, one year follow up. Again, their outcome measure was with the patient is happy. They like it. In this particular case, all patients are satisfied. They reported no complications. Also, one of the authors was disclosed as a consultant for the manufacturer. Again, you have to look at this as to what type of bias may or may not. A retrospective review of 86 digits, 90-day minimum followup, 58 implants, 28 K-wires. The conclusions of these study in terms of malunion, nonunion or infection, there was no clinically significant difference. Radiographic union was actually higher in this with the K-wire as opposed to the implant. However, okay, when you're looking at if your outcome measure is just radiographic union, the K-wires had it. If you look at that the implants with nonunions were asymptomatic, the conclusion was in terms of the impact it had on the patient, that both the implant or the K-wire remains viable options. Okay, so you have to look at what the end conclusion is. Another study, retrospective, pretty evenly stratified, 15 digits with K-wires, 13 with implants, the primary outcome measure, patient pain and patient satisfaction. If you look at it, that the implant, the digital implant on the average performed better in patient satisfaction. Again, the conclusion was just based on patient satisfaction. Ellington, retrospective study of 38.

    [15:00]

    This is two component, intramedullary implants, 27 patients, noticed union in 23 out of the 38 patients. Complications rate fairly high in this study, 55%, half the patients involved in it, 21 out of 38 patients. The complications were nonunion, bent implants, fractured implants or rotation of it. Remember, again, the medullary bone in the canals of the phalanges is not good bones. It’s kind of crumby, crappy bone. Implants and any kind of fixation device, screws, implants, rods can actually rotate there. To prevent that, really you'd need to be stapled to prevent axial rotation. But again, the staples come with their own set of unique problems. Bottom line, in looking at implants versus other means of fixation, the advantages of implants is absence of exposed hardware. They are built in. In some cases, they are built in flexion. You can have a 10 or 15 degrees flexion component of the implant. In most cases, if it sits there, it will prevent to a greater extent than, say, a K-wire which has no resistance to axial rotation. They can prevent frontal rotation. The disadvantage side of using an implant, it does take increased operating room time. There’s a learning curve there. Once you get adept at doing it, it’s really not a significant increase in time. You can put these in fairly quickly as the surgeon skill increases. There is a learning curve the surgeon does need to do, have some training in using the device, usually on a cadaver model, and of course, cost. The cost of an implant compared to a K-wire is significant. I don’t know about which hospital you practice in, but I think too many hospitals that are a lot concerned about cost of implants these days. At the end, what is it that you’re looking for? What if you infused with a wire or put a digital implant in there? The end goal is did we rebalance power about the MTPJ? Did we restore a rigid lever on for the flexors to stabilize the MTPJ on propulsion. In doing so, that enhances propulsion, enhances stability at the interphalangeal joints, certainly want to have minimal morbidity. You don’t want to reach those goals but you’d have a fast swollen toe for six months. And, is the patient happy? Is the patient satisfied? Would the patient do it again at the end of the day? There’s my little granddaughter who I’m going to home and see later. Thank you very much. You’ve been a great audience. We appreciate your attention.