Lee C Rogers, DPM reviews the 2015 Consensus statement on offloading and diabetic foot ulcers. Dr Rogers also reviews the critical triad for the formation of ulcers and the use of contact casts to heal them.
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Lee Rogers, DPM
Amputation Prevention Centers of America
White Plains, NY
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Robert Frykberg: As a good friend of mine, Larry Harper [Phonetic] said years ago, “It’s not what you put on the ulcer, it’s what you take off that counts.” It’s a very passionate statement. As I alluded to earlier and as Lee alluded too. Without paying attention the basics of wound care, you’re never going to be successful in healing your wounds. With that, we’ve asked Lee Rogers to come back and talk about offloading and the critically important function it plays in wound management and his techniques for affecting a proper offloading. Let’s welcome back, Lee Rogers.
Lee Rogers: Okay. Offloading, I find it one of the most boring topics that we have to deal with in wound care. But it can be interesting if you know some of the pathophysiology of the diabetic foot ulcer and where pressure comes into play and then target your offloading to that so that’s kind of what I did here. We’re also going to review the 2015 consensus document on offloading diabetic foot ulcers and it hasn’t been published yet so you’ll get a sneak peek and Dr. Frykberg and I were on this panel in Philadelphia. I think it is supposed to be published in January, is that right, Bob?
Robert Frykberg: JAPMA.
Lee Rogers: Yeah, JAPMA in January. The first thing is when we look at healing ulcers and preventing amputations, it’s not one single thing you can do. There’s not one step that makes all the difference. We talk about it as a pie concept that there are many pieces of the pie that all have to come in together and get this ulcer to heal. It’s everything from managing infection, diagnosing and managing vascular disease, debriding, promoting granulation, wound closure, all these things that I mentioned in the last lecture. But really if you consider this a pie, the pan that the pie sits in is offloading. Offloading is so important during the duration of wound healing and even after the wound has healed in order to prevent the ulcer from recurring. You’re probably surprised, Bob, that I put this in there. Remember when you taught me about this in year 2000 in Des Moines, the Rothman model. This is a epidemiological model where what Rothman said that if you have, in some cases, you need multiple components to all add up together to cause some type of outcome. Let’s take heart attack for example. For an MI as the outcome, hypercholesterolemia alone won’t cause an MI but hypercholesterolemia as a component cause with lack of exercise, with obesity, with diabetes. All of those things add up together to make a sufficient cause for having an MI. That’s been applied in the diabetic foot by Gayle Reiber and this is what she calls the critical triad. What you see here that these components, neuropathy, deformity and trauma alone would not cause diabetic foot ulcer. But when all three of them come together in the center, that’s when you get a foot ulcer. We’ll talk about each one briefly. Neuropathy, it’s the key component for all diabetic foot ulcers. It affects all three divisions of the peripheral nervous system, sensory division, that predisposes patients to unfelt repetitive trauma. Motor neuropathy leads to clawed toes and foot deformities which increases pressure on the feet and then autonomic neuropathy causes skin dryness and deteriorating skin condition which can lead to cracking and ulcers. So then looking at deformity, deformity is really any foot condition which causes an increase in the peak plantar pressure. That could be hammertoes, bunions, previous amputations, Charcot foot. A very important study looking at the combination or where really deformity comes into play with foot ulcers was done by Masson in 1989, where they looked at two groups of patients, one with rheumatoid arthritis and another with diabetes and neuropathy. They looked at patients that had deformity. You can see in the first column, that’s the peak plantar pressures in kilograms per square centimeter. You can see that the rheumatoid patients and the diabetic neuropathic patients had about an equal amount of pressure on the bottom of their feet so they had an equal amount of deformity. But if you look at the rate of foot ulceration over on the right hand column, the rheumatoid arthritis patients didn’t ulcerate at all, not a single one of them ulcerated.
But 31% of the diabetic foot patients with neuropathy ulcerated. That shows you that it’s not deformity by itself, it’s deformity plus neuropathy that leads to the ulceration. If you have somebody who has a fresh diagnosis of diabetes, they have a deformity but they don’t yet have neuropathy, the risk of ulceration is really low. It’s after they convert and become neuropathic that they have an increased risk of ulcer. One of the signs of deformity is a plantar callus. Plantar callus alone is associated with an 11 times increased risk for developing a foot ulcer. Limited joint mobility is as important as deformity. Limited joint mobility can’t be seen. You have to actually put your hands on the patient and test them in an exam to determine whether or not they have limited joint mobility. But if they want, if a patient comes in and they have a Charcot foot deformity or they’ve a hallux abductor valgus, you can see that and you say, “Okay, well, this is a deformity, this is a risk factor for ulcer if they have neuropathy present.” But these things are also risk factors for ulcers and they’re not deformity in the true sense of the word deformity but they are equal to deformity in the biomechanics of it. Hallux rigidus has a 4.6 times increased risk of a foot ulcer in somebody with neuropathy, equinus 2.3 and even decreased STJ range of motion. The last one is trauma. You know what we should do sometime, Bob, is play the video from Paul Brand, you know that lecture that we have. Paul Brand’s last lecture before he died. He was, I think, 89 at the time when he gave the lecture. Paul Brand was a hand orthopedic surgeon from Britain and spent his time in leprosy clinics in India. He really discovered the link between neuropathy and ulceration. At that time, it was leprosy that was causing neuropathy. They thought that the bacteria itself was causing the ulcers but he was the one that discovered that it was the neuropathy from the leprosy that cause the ulcers. He talks about different types of trauma that lead to these ulcerations. The first type of trauma is a high energy low duration trauma and that’s like stepping on a nail. High energy punctures the skin, low duration, just one single time going through. That’s a trauma that we typically think about. There’s also low energy and long duration trauma and that’s like a pressure ulcer. Low energy, just constant pressure on the heel on a bed, long duration of time, that will cause an ulcer. But then with the diabetic foot, it’s really the moderate energy, moderate duration trauma that causes these diabetic foot ulcers or these neuropathic foot ulcers when he was looking at them. That’s basically an increasing pressure, repetitive stress and not necessarily this high impact. More concisely what it is, is it’s the cycles of repetitive stress times the pressure that equals the trauma. When you’re trying to remove the risk of trauma so let’s say you have a patient with neuropathy and deformity, they got two of the critical triad already and you can’t do anything about those two, you can’t get rid of neuropathy and you could correct the deformity or offload it but you’ve got deformity and neuropathy, you want to reduce the risk of trauma. Well you have to either reduce the cycles of repetitive stress or reduce the pressure. That will reduce your trauma. Cycles of repetitive stress are numbers of steps per day the patients take, the amount of walking that they do. We do talk about prescribing activity kind of like we prescribe a drug. I’ve heard numbers all across the board about the average number of steps per day that somebody takes and I’ve heard that the average human takes 10,000 steps a day but that’s not the average American, I don’t think. I’ve got two medical students with me from Germany who are up here in the fourth row back and Germans probably walk 10,000 steps a day. I had a pedometer for a while and the only time I walked more than 10,000 steps is when I went to Disneyland with my family and I really hurt afterwards. The average diabetic walks even less than that. My average number of steps per day walking around the hospital and doing the active things that we do on a daily basis was about 5,000. But I think somebody with diabetes probably walks maybe 2,500 and 3,000 steps per day. You can find the threshold and reduce the risk by even asking them to walk fewer steps per day. The other way is to take the pressure off. Cycles of repetitive stress times pressure equals trauma.
You can take the pressure off by any number of these ways from prescriptive shoes to removable cast walkers. If you’re healing an ulcer, you might use a total contact cast and it’s always does the end justify the means. You have to find the right thing for the patient to offload. The effective offloading techniques, especially for healing diabetic foot ulcers are either total nonweightbearing, bed rest, wheelchairs or crutches. Now those are not often the best thing for the patient. They are the best way to offload wounds. If you have no pressure on that foot, that ulcer is going to heal relatively quickly. But if you put somebody on bed rest, they already have skin breakdown on their foot. They’re at risk for skin breakdown in other locations. You also don’t want them to decompensate from being in bed for a long period of time. Wheelchairs, the same thing. Wheelchairs are difficult in some home environments to maneuver inside the house, get in and out of the car. Crutches, most patients with crutches, if you’ve ever used crutches, you realize how much energy it actually takes to use crutches. People with diabetes who are obese don’t have the cardiovascular reserve to use crutches. That’s why we resort to other methods where we can try to keep the patient weightbearing and keep them active and still take the pressure off of their foot. We have total contact cast, different foot cast or boots, these removable cast walkers, PTBOs, so things like that. Let’s just talk about offloading and common sense. This is a traditional total contact cast on the left and a removable cast walker on the right. That’s an aircast. If you look at them in the laboratory, you see that they offload the plantar surface of the foot about equally. The total contact cast and some of the removable cast walkers take the same amount of pressure off the bottom of the foot. But when we look at them, you would say, “Okay, well then they’re equal.” But when you look at them in the clinical setting and you see how often they heal wounds, we can see that the total contact cast heal wounds much faster than a removable cast walker does. The reason for that is based on a study that David Armstrong did where he gave patients a pedometer and they wore one on their hip and he told them that he was doing a study on the number of steps per day that they were taking so he lied to them. Then he took another pedometer and buried it in their device and they didn’t know it was in there. They did a study comparing the number of steps per day that their removal cast walker took and the number of steps per day that their hip took, so getting an overall just a feeling on temperature on compliance. What they found was that patients only wore their device for 30% of their walking steps even though they were told not to take it off. They only wore it for 30% of their walking steps. There’s a few reasons for this. One is that when patients go home, they kind of feel that their home environment is their safe environment. We know that people with diabetes actually walk more steps per day in their home than they do outside of their home but they think that their home is safe and they take their shoes off and their device off and they walk around barefoot in their home. One of the things we can do is convey to them that you actually take more steps per day just walking around your house than you do out and about, so it’s important that you wear your devices, even at home, you got to wear your devices. That poses some cultural problems in cultures like when I was in the Middle East, you can’t wear shoes in the house and so you have to work through some of those. We’ll talk a little bit about total contact cast because really these are the best method of healing diabetic foot ulcers. How did total contact cast work? There’s a few ways that they work. The first thing is that they act as an exoskeleton. An insect, a crab, they have exoskeletons. Their skeleton is on the outside, the soft stuff is on the inside. We have a skeleton on the inside. But what the total contact cast does is it forms an exoskeleton around their extremity and the pressure gets put on to that exoskeleton and not on the skeleton on the inside and it takes the pressure off the plantar surface of the foot. The other thing is that most people’s calves to their ankles are somewhat conical in shape, unless you have cankles that is more cylindrical. But most of the time, they’re conical in shape. You could picture what happens when you have a total contact cast around a conical extremity that the pressure is going to be forced and wedged into that cast and you’re going to put more pressure on the tibia and less pressure on the plantar surface of the foot. It offloads the plantar surface of the foot about 30% with a total contact cast. The other thing is they immobilize the ankle. If you immobilize the ankle, you don’t have plantarflexion. You’re not going to have that plantarflexory pressure at the midfoot and at the forefoot. It also reduces the contact time of the affected foot on the ground. Try walking and not moving your ankle and keeping your ankle completely at 90 degrees and take a walk down the aisle.
You’ll notice that you’re limping because your foot is not on the ground for the same amount of time that your other foot is on the ground because you’re not pushing off with the forefoot. It reduces the amount of time that the foot is on the ground which reduces the pressure. These are just cumbersome and patients walk fewer steps per day when they have a total contact cast on versus anything else. That reduces the number of steps they take. Then the last is that they’re irremovable. It forces the compliance for the patients. Traditional TCC is either made up of a plaster or a plaster and fiberglass and they look something like this. It’s not a French flag. It was actually for the 4th of July, we did that for our patients. But now we have the newer device which we use very frequently which is the TCC-EZ. It’s a self-contained kit and it rolls on like a sock and it hardens in over about 15 minutes or so and you put a boot attachment on that the patient can walk. This is the only one I ever put on. We’ve done thousands of them and I did it once for a video so I could show you that I put it on once but they train your nurses how to do it and you don’t have [indecipherable] [16:24] to put another one on after this because it’s that easy to do. The other nice thing is that with total contact cast, you can marry your offloading with something else. I don’t know where you all are from. You maybe only able to marry a man and a woman together in your state but in California, we can marry anything we want together and we marry our offloading with all sorts of things. Using negative pressure, we can do it either with a removable cast walker as you see here, running the host out the distal end or we can bridge it. When you look at the peak plantar pressure of somebody walking with negative pressure on the plantar surface of the foot, you might think to yourself, well, that foam after it compresses, it’s pretty hard if you tap on it. It’s pretty hard so you would think that it would increase the pressure because you have something hard that’s stuck to the bottom of the foot when a patient is walking on it. It might increase the pressure. But if you bridge it and you use a removable cast walker, you can see that there’s no change in the peak plantar pressure. Offload is just as well. You can feel comfortable using those two therapies together. One of the things that we do with the TCC-EZ is we actually use, this is a particular KCI dressing called the bridge dressing and it comes all in one piece and you can just bridge it all the way out from underneath the cast and all the way up on the knee. Then you’re not having any of the host or the track pad underneath the cast which you might worry about causing pressure and causing an ulceration. This patient had an Achilles tendon ulcer. It wasn’t a plantar foot ulcer but you can still do it with a plantar foot ulcer. You can still bridge all the way up to the knee. You can see there’s plenty of room left. You can also combine your offloading with other therapies like any of your skin substitutes that you’re using. This is a plantar TMA ulcer, plantar distal TMA ulcer. First thing you check any time when you have a plantar distal TMA ulcer is you check for equinus. You want to make sure that there’s no residual equinus and that can be resolved pretty easily with the tendo-Achilles lengthening and relieve that pressure. But you can take your graft, put it on the wound. This is basically how you do this particular cast. It’s just a few steps and this is our nurse doing it. The first is a stockinet then there’s this pad that puts in place to protect the malleoli and then to provide you a cutting surface when you’re cutting it off with the cast saw, so you don’t risk cutting the patient. Then the only padding really is that that second layer of padding which the video skip through but it’s just like a thick tube sock. You wet it. It’s fiberglass. You wet it and roll it on like a sock. You wanted to stop at the thickest part of the calf and that’s because again because of the conical shape of the lower extremity that’s going to provide you your best offloading if you stop the cast at the thickest part of the calf. This is on a TMA obviously but even if they were toes, we would bend the residual amount of the cast up and that would protect the toes. Can you advance for me once, Allen?
Maybe it’s not working so maybe hit Escape. There it goes, never mind. Our document that is going to published in January 2015 in JAPMA was a consensus document. These are some of the people that were involved. You probably know Rob Snyder. Dr. Frykberg’s on there. Jeff Jensen who helped developed this, Desmond Bell. We got together and reviewed all of the papers that provided any evidence on offloading and all the different types of offloading that existed and came up with a consensus document. These are small text so I’ll just read them for you but these are the five consensus statements that we came up with based on the evidence. Consensus statement number one, the VIPs which I talked about earlier, that was my contribution to the document. The VIPs, vascular infection and pressure, are essential to diabetic foot ulcer care. Statement number two, the use of offloading is essential to diabetic foot ulcer care and the evidence is clear that adequate offloading increases the likelihood of DFU healing. Three, for guidelines on the use of offloading in the Charcot foot, the panel endorses the Charcot foot in diabetes consensus report published in 2011 and that was one of those documents that I had suggested earlier. My e-mail address will be at the end, again, you can e-mail me if you want a copy if it. Then number four, total contact casting is the best method for offloading plantar DFUs. It has most consistently demonstrated the best healing outcomes and it’s cost effective treatment. Then five, which is this is what we’re trying to overcome is that there currently exist a gap between the evidence that supports the efficacy of offloading DFUs and what is actually performed in clinical practice. Looking at the TCC evidence, it’s well supported by multiple randomized controlled trials and systemic reviews. It’s more successful at healing ulcers than removable devices and that’s based on that one study I showed you just a little bit ago. Then it’s also associated with a lower cost of care for ulcer treatment mostly because it shortens the time needed to heal a diabetic foot ulcer. But this evidence practice gap is the problem. We know it works really well but not a lot of people are using it. Why aren’t people using it? Well, it’s cumbersome to put on. It can cause complications. If you do it incorrectly. You have to be trained appropriately in how to do it. It’s time consuming. The traditional total contact cast took at least 20 minutes to put on. You'd have to have a dedicated staff person there and then you’d have to dry afterwards so you tie up your room for another 20 and 30 minutes while it’s drying so for the patient can stand on it. Some of the ways we get around that is by using some of these premade, prefab kits that just roll on. It relieves a lot of these impediments to using a total contact cast. But we know that in a retrospective study of 108,000 patient visits in 18 wound centers that only 6% of patients with diabetic foot ulcers had a total contact cast put on even though it’s the best method to offload. That’s where you think the experts are in a wound care center. Another study found that it was only used in 1.7% of wound centers out of 895 centers surveyed. We have a long way to go to make up that evidence practice gap. You can also use removable cast walkers and in some cases, total contact cast is not the right treatment for everybody so we’ll use removable cast walkers in those cases. We try to take the removable cast walker and render it. You can’t really render it irremovable but you can render it less removable by wrapping it with Coban or you’d ruin it if you wrap it with fiberglass but you can do that. You could put a ziptie around it, actually some people are doing that. The patient can take the zip tie off but you’d see if it was off. Some of it is just that they want to make their doctor happy. Most patients do want to make their doctor happy. If you tell them not to take it off then hopefully, it will still be on when they come back. Patients can walk pretty effectively with a removable cast walker when they’re being offloaded. Another option is a Roll-A-Bout and unfortunately, this isn’t playing but I’m sure you’ve all seen Roll-A-Bouts and how they work. This lady had a Charcot foot reconstruction, external fixator. There she goes. Here’s a couple of new things that are out. I’ve tried some of these. I’m not sure that they are better than a total contact cast but they may be replacement in certain cases, maybe for some younger patients that are more stable. But there’s the toad brace. There’s also this freedom leg brace.
This one doesn’t look very easy to get around. I haven’t tried this one actually. You tried it Bob?
Robert Frykberg: No.
Lee Rogers: Then afterwards, you need long-term protection. Your offloading is not done after the ulcer heals or your Charcot foot reconstruction is done. You got to do something that prevent this ulcer from coming back. I finished five minutes early. I made up for my time last time. But I’ll leave you with this quote from Hannibal, not Hannibal the cannibal but the other Hannibal who’s a general. He was trying to conquer the Roman Empire and he had a bunch of elephants and he wanted to move these elephants over the Alps from Central Europe into Southern Europe. All of his generals told him that it’s impossible to move these elephants over the Alps and he said, “I’ll either find a way or I’m going to make one.” That’s true in what we’re dealing with, with diabetic foot ulcers because there are so many people that will tell you that whatever it is, is impossible for you to do and these people are going to end up with an amputation anyway. But if you have the right philosophy going into it, I think you can make a big difference. Thank you.