Suhad Hadi, DPM reviews the statistics and risk factors for amputations. Dr Hadi discusses the different types of partial foot amputations with emphasis on complications, morbidity and prevention of potential deformities.
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Release Date: 03/16/2018 Expiration Date: 12/31/2018
Suhad Hadi, DPM
Louis Stokes Veterans Administration
Akron Community Based Outpatient Clinic
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Male Speaker: Now, we all know that our job is to prevent amputations but we also recognize that partial foot amputations are frequently necessary as a limb salvage measure and we have to orient ourselves in that way. I’ve asked Dr. Hadi for a special return engagement to talk about partial foot amputation with specific focus on the most common amputations. That would be the forefoot amputation. Let’s welcome back Dr. Hadi.
Male Speaker: I love those feet images. They’re great.
Suhad Hadi: I’ll get to it. I got you. Alright. Thanks again and thanks to all the diehard who are still sticking it out. Partial foot amputations, we’re all going to run across them somewhere along the way. It’s important to remember the statistics and they account for over half of 80,000 diabetes-related amputations per year. Greater than 60% of the nontraumatic lower limb amputations and over 65,000 nontraumatic lower limb amputation diabetes in 2006 alone. The big thing is that we’re still averaging about an 18-month timeframe between first and second amputation so a lot of these forefoot amputations we’ll see in progressing to something a little bit more proximal. Fifteen percent of the amputees are diagnosed with diabetes at the time of their amputation despite our continued efforts towards a collaborative approach to diabetic foot, diabetes in general. Twenty five percent of foot amputations are going to progress to below-knee amputation. Again, we’re looking at an 18-month interval between first and second. The positive side of things is that we’re seeing a higher return of function in our below-knee amputation patients, probably due to improvements in prosthesis and rehab potential and a lot of the populations now. Risk factors for amputations, peripheral neuropathy, altered mechanics. Peripheral vascular disease is really the number one, I think, risk factor in regards to amputation, neuropathy being there for ulceration and the problems that might initiate a lot of that, history of ulcer and history of amputation. I love this picture because honestly in practice, I think you think you’ve seen everything. I haven’t been in practice that long in about 15 years but still this patient comes in and the nurse comes out and she couldn’t control herself because she really just wanted to laugh at this patient and she told me to walk in. I walk into the office and he has this butterscotch candy stuck on the bottom of his foot. She didn’t want to remove it because she don’t want to embarrass him that she found candy stuck on the bottom of his foot. I asked him, I said, “Do you like butterscotch candies?” He said to me, “Yeah, but I happen to be missing one of mine.” That was literally his answer to me. We took it off his foot and showed it to him. The bad thing is what I really wanted to hit home, I think I’m missing, oh here it is, is the impact it already had made just from him leaving the skilled nursing facility and coming to our clinic. It was his first time in our clinic. They sent him for a heel ulcer that was occurred on that side, you can kind of see it. But what would have happened here, how long would he have been walking on that? When I told him about it and stressed to him and try to educate him, probably one of the most frustrating things was his answer to me was, “Well, I guess that’s the result of neuropathy.” But you try to hit home the point. He wasn’t getting a podiatric follow up so he started establishing with us. This is another study, so like I said, this was from residency and I still carry this slide with me. So here we are. I did residency in ‘97, here we are with this guy with the butterscotch candy and this guy with the Miller Lite cap stuck on the bottom of his foot. He swears to me he’s not drinking anymore. He swears to me he’s not walking barefoot at home. I’ve had this since residency, actually a co-resident of mine, Rose May Michelle [Phonetic] gave me this picture. These things happen and these are some of the things that will predispose us to amputations and the recurrence of amputation. Some of the indications that we have for partial foot amputations, infection, ischemia, revision to a more functional level and which I think hit home the point that Dr. Kimmel mentioned this morning, surgical offloading. Sometimes, an initial amputation results in transfer lesions or progressive deformity given his natural history and you might have to find yourself doing revisions, and then reduction of an initial deformity. The big thing when you’re planning even forefoot amputations, digital, ray and midfoot amputations, you want to make sure how to understand how you’re altering the mechanics in these patients. You want to understand what subsequent instability is going to be in play, plus what instability is the patient starting with? Because when you try to shoe these patients later, you want to give them something that at least maintains the stability they have or doesn’t damage it further, and then subsequent deformity that may result in new areas of pressure. In these patients, I read an article where some of the orthopedic mentality is don’t do a distal TMA if you’re going to have a plantar flap that’s not healthy, viable, thick, good padding that will result in bony pressure at the distal TMA.
Go proximal to a level where you’re going to have good soft tissue envelope for closure, that it’s less likely prone to repetitive injury. When we talk about amputations in the forefoot, digital amputations, they’re generally well-tolerated. I don’t think many of us have a problem shoeing a digital amputation. I don’t think there is much loss of function in patients with digital amputations. They still walk with a pretty decent speed and there really is not much progressed distribution of weights in the contralateral limb. There may be slight compromises in terms of running risk for secondary deformities. The adjacent toe is a big one because you lose the buttress effect. You can see in this picture here where you lose a toe and then you start to see drifting of adjacent toes which will result in subsequent deformities as well. Those are things to keep in mind with the digital amputations. The big thing despite saying that they’re well-tolerated is to take that with a grain of salt because there was a study done by Griffin and his group that they did the digital amputations, however, they found that toe amputations are actually significant predictor for future limb loss. They actually have a high morbidity associated with them. Despite the ease of procedure, despite the better outcome in regards to shoeing these patients in functional capacity they have afterwards, they’re still associated with a high morbidity. Hallux amputations, I think it’s really important if you’re going to amputate a hallux or a partial first ray to understand the natural history of this level of amputation. These amputations come with progressed digital deformities. This patient actually had a hallux amputation which resulted in plantar ulcerations. A sesamoid complex wasn’t taken out, they were hypertrophied so we went in and took out the sesamoids. But his toes had contracted progressively over time from his amputation. His fifth toe ended up cocking up. Well we told him we could probably reduce the deformities and try to get it straighter and reduce the pressure and he just wanted it amputated. He don’t want to deal with it. Some people would say this patient would be better served with a TMA. I probably don’t disagree but this gentleman wanted to save all the toes that he could possibly save and I would probably say somewhere down the road he might end up with a TMA. But you want to worry about the progressive deformities that are associated with the hallux amputation. Again, the gait alterations. Shoe gear and bracing become important. We’ll talk about that a little more after we talk about the first ray. Partial first ray amputation, I treat them like a hallux amputation. You’re going to lose that step off, that propulsion and you’re going to see a lot of the same sequela long-term that you would see with a hallux amputation. I’ve talked to some people who actually feel a partial first ray is not a viable option and I’ve heard some people will go straight to a TMA from a first ray amputation. I thought this review was interesting. Roukis and one of his partners did a systematic review of 435 patients and they found with partial first rays that there was about a 20% re-amputation rate in these patients. They found that one out of every five partial first ray amputations required a more proximal amputation, therefore, questioning the viability or the durability of a partial first ray amputation long-term and felt that maybe a midfoot amputation would be more functional, less prone to progressive deformity and easier to shoe and accommodate in this population. I don’t know that I see one out of five as a horrible outcome. I still do partial first ray amputations. I think you do have to watch these patients a little bit more closely. I take this too with a little bit of a grain of salt and I think everybody is a little different in that perspective. But I do see more people lean towards the partial first ray not being viable and would actually opt to do a midfoot amp. I have a hard time selling it to the patients. I actually have easier time selling to them the deformities that are going to come later as well as the importance of appropriate shoeing and bracing long-term. And so that becomes important too. There was a time when shoeing this population with a lost hallux involved, actually that shoe was forefoot rocker at the appropriate level and then insole with an appropriate amp filler. I don’t think that’s enough if we’re going to keep these deformities from progressing. I think sometimes even bracing them aggressively with an AFO or possibly a double upright is a little bit better to help them in the forward propulsion and gait. I think long-term, that will give you a little bit more success. Same thing with these studies’ retrospective review, this was coming in Steinberg and Attinger and their group. They did a study of partial first ray amputation outcomes and they did 20 patients, 12 of them of which received prophylactic TAL along with the partial first ray amputation in an attempt to prevent forefoot reulceration or transfer lesions. Eight of their 12 TAL patients had no recurrent ulceration at three years which is a pretty good follow-up. Four of them had further debridement or moved on to a proximal TMA. All of the once without a TAL did develop further ulceration and had to progress to amputation.
There is some viability to incorporating a TAL into your procedures with this population as well. I think if you look into the studies, sometimes, there was a vascular component that may have also led to some of the failure that you see here or deformity that may have been present that worsen with the partial ray amputation. Lesser ray amputations, at one time, were frowned upon as not successful causing the midfoot or the forefoot to be less stable. It’s more commonly tolerated in the central and the most lateral rays of the foot. It’s important to keep a good portion of the metatarsal to maintain that midfoot stability. The risk of transfer lesions in reulceration are probably the biggest thing you’re going to deal with, with the ray amputation. And then again risk of digital deformities based on the gap that you leave between the adjacent digits and loss of that buttress effect of the digits, the toes. So Pinzur and his group found about a 37% success rate with partial ray amputations. This success rate was pretty much reproduced by several authors subsequent to that. [indecipherable] [11:08] and his group at UT did a study in ‘99 that showed a 60% success rate with ray amputations. I feel rays amputations are probably about that successful. I think if you’re careful in planning and careful in the amount of resection and the way you can re-approximate the amputation distally bringing the toes a little bit closer together will give you a better outcome long term. But they had 85% patients, a follow-up average of 33 months. These are some of the reasons that the patients went to a ray amputation. This was their levels of ray amputations from first ray and fifth ray to multiple rays, the distribution. Again here, same thing with the distributions and they again found that about 60% healed the initial ray level, 41% went on to more proximal amputation. This is going to be a recurrent theme because it seems in most of the studies, especially the most recent studies where we’re recognizing the importance of peripheral vascular disease in this population, we’re going to see a recurrent theme where ischemia has been the culprit and many of the patients have had to go back to a more proximal amputation level. Again, this was their outcomes. Transmetatarsal amputations, indications, infection, ischemia and gangrene progressed deformity or revision surgeries for the reasons we’ve mentioned in the first several types of amputations. This is a classic example, so this is the patient from the dorsal view right here. He had actually a ray done, third ray done and so you can see the subsequent deformity that resulted in the digits, loss of the buttress between the second and third. The second toe deviating. Fourth and the second toe deviating. He developed an ulcer sub IV which became infected and he actually did have tracking along the flexor tendons distally and proximally and I don’t think you can really tell here. We offered him another ray versus a TMA and he felt that if he was going to have more deformities and more transfer lesions, he would rather go to the TMA. In that respect, I think that was actually a reasonable choice for this patient, did a nice distal transmetatarsal amputation, shoed him appropriately and he’s actually doing very well long-term. Outcomes with the surgery, 1967, one out of 15 TMAs failed after five years. In ‘92, Sanders [Phonetic] and his group, 88% of TMAs healed with a two-year average follow-up. In 1980, again, about 50% needed a higher level amputation, meaning 50% had a success rate. In [indecipherable] [13:39] 1997 demonstrated 60% healed TMA level at a 15-month follow-up and then ischemia led to a 90% chance of a higher amputation level. Again, just like Dr. William said earlier, we say that we heal these patients, we treat these patients but it’s never just a single effort. It is a collaborative effort. We definitely need the vascular guys on board. Again, this is another outcome in regards to TMAs. And I’m getting the your time is running out signal but there are a lot of studies supporting the TMA. These several studies support the Achilles lengthening, percutaneous technique versus gastroc resections to help offload the forefoot and reduce progressive contracture equinus deformity in patients with amputation to prevent some of the distal transfer lesions that might occur. I think some of the long-term considerations with some of the ray amputations, especially the first ray and the TMA includes shoe gear, bracing and long-term function and I think it’s helpful to consider something like a dynamic AFO in your TMA population to help them with the forward propulsion and reducing some of the forefoot pressures that come with gait with that level of amputation. Helps you stabilize the deformity, the Blue Rocker AFOs, the one I like best, it’s lightweight. This is just an example, this is a gentleman who had a below-knee amputation and ends up with a TMA on this side and could not ambulate because of the instability.
Once we added the AFO brace, he actually ambulates with the assistance of the cane rather than not ambulating at all. He feels a little bit more stable and that’s something we can afford all our patients. If skin integrity is of a concern, the metal hybrid shoe brace is really effective as well and gives you the same effect that you want out of the AFO without the extensive soft tissue contact of an AFO-type brace and so it lessens the risk of ulcerating along the lower extremity or the lower leg. Keys to success with amputation planning, you want to make sure your vascular supply. This has been shown to have the greatest impact in regards to need for more proximal revision or lower leg amputation. You want to make sure you eradicate any extent of infection. You want to take in account the patient’s functional capacity pre and post and you want to consider appropriate shoe and bracing long-term and then long-term foot care program and access to care. Good day [indecipherable] [16:01] take a foot.