How to Apply a Total Contact Cast
Thu, 01/04/2024 – 14:09
Hi, I’m Dr. James McGuire, I’m the Director of the Leonard Abrams Center for Advanced Wound Healing at the Temple University School of Podiatric Medicine in Philadelphia. Today you’re going to see a demonstration on the application of the total contact cast, using a kit that has been provided for us by BSN Corporation. The kit we’re using today is the Cutimed Offloader Select.
The way the total contact cast works is by placing a cast on a leg and lifting the leg so that the foot is elevated off the floor slightly by transferring weight from the plantar surface to the cone of the leg, to the vertical surface of the leg. It’s not so much in stabilizing the foot within the cast, although that’s very helpful to anything that reduces shear movement back and forth and anterior /posterior movement decreases the chance that they’re going to develop some sort of ulceration or irritation within the cast.
You always prepare the wound. You would take a dressing, apply the dressing, whichever type you’ve chosen, to the plantar surface of the foot, and attach it with a loose dressing that’s not a great deal of padding.
The cast will do much of the work to protect the foot. But you hydrate the skin. We use either a lambswool or, in this case, we have 2×2 gauze squares. So we’re going to take one 2×2 gauze square and put it between each digit. What that does is it lets air flow between the toes, prevents interdigital maceration, and prevents irritation between the digits in the cast itself.
The next thing you do is we’re going to put a stockinette on the foot and we’re going to cover the foot from toes to the knee and I’ve already prerolled this one, so it goes on a little easier and we’ve also cut it so it’s the right length. This particular kit has a stockinette that’s very tough and has a nice consistency to it so that kind of protects the skin. It makes it easier later to remove it when you use the cast saw to cut through. It’s a little resistant to the movement of the saw and the skin. You want to have an overlap down here at the end of the toes so that you’re able to put put your finger at the end and bring the material back slightly, so that one you pad the tops of the toes, which is the most likely place where patients will have irritation from the cast and also that you leave a little space and you don’t do this when you apply the cast. If you do that, you’re going to pull the toes back, create digital pressures and you may cause some irritation.
The next thing we’re going to do is pad the patient’s foot and we’re going to pad the malleoli, which are the two places where you get the most likely going to get irritation from pressure on the cast and also the anterior tibial crest, which is another place where the cast tends to cause irritation or rubbing. For that, we’re going to use felt, adhesive felt. Take these, apply them to the malleoli so that they’re protected from cast irritation and also when you go to take the cast off later, it’s helpful to have those covered or protected so the saw doesn’t irritate them. Next thing we’re going to do is apply adhesive felt to the front part of the leg.
We’re going to go here and we’re going to go all the way up. We’re going to go above where we’re going to want the cast to end and how high does the total contact cast go? Basically, you feel around on the lateral side of the leg and you’re looking for the fibular notch where the common perineal nerve comes around and goes down to innervate the muscles of the anterior leg.
When you find that, that’s going to be the common peroneal nerve. You want to make sure that that is not compressed by the cast. Your cast is going to be below that point, which is usually right around where the tibial tubercle is. We’re going to go above that point and then I’ll show you something else that’s helpful in making sure that that’s not irritated by the cast. We’re then going to come down the foot and we’re going to go to the end of the toes. We’re going to cut a little piece off right here, or you can cut it later, and I’ll show you how to do that. You can either remove it now, or you can remove it later. If we do it now, start by taking the backing off, and don’t take it all the way off, it makes it very difficult to do. Put it on the leg, and you’re going to run this down the tibial crust. As you come down here, make sure the patient’s at 90. You’re going to come around, and just as you come to the top of the foot, bring your stockinette back, and make sure you secure it with the adhesive felt. Because this is sticky, cut this before you take the paper off.
So make sure you take that, and save this, or you can use it. Lots of times we’ll take this, and we’ll use this on an extra, a place where you get some irritation, like the lateral side of the foot. But we may split it up into one for the lateral side, one for the navicular, or one for the head of the first metatarsal, where there’s some extra irritation. But that’s an extra piece that you can utilize for that. The next thing we’re going to do is apply cast padding. We’re going to cover the toes with some foam, and then we’re going to put cast padding on the rest of the cast.
So we’ll come down underneath, apply this back to and behind the metatarsal heads. Bring the foam up over, and again, you’re making sure you don’t jack it back and go tight. Make sure that comes back over the ends of the toes, and pinch it. Then take your scissors, and cut a seam.
Next thing we’re going to put on is our cast padding. You can start distal or proximal, I don’t think it matters too much. much. If you want to start down here, wrap the foot, immediately turn a little bit, kind of come around the back of the heel, kind of come up over the foot. There’s a lot of different techniques for doing this. Every time you go to change an angle, if it looks like you’re going to have to bunch the cotton up like I’ve been doing here, just tear it and redirect.
I don’t like to put a ton of cotton over the end of the toe or the end of the cast because I want it to breathe a little bit. There’s a little technique for getting it to be able to breathe. You can go heel to toe. There’s nothing wrong with that. Coming up through here, but again try not to put tons and tons of material over the tips of the toes because it prevents air flow from coming up through the cast.
Once you’ve got the cast covered and the heel covered, then we’re going to go back down here. A good way to do this is you can make stirrups front to back or side to side and then do one front to back around the back of the heel, and then you can do one more over the malleoli. See how you’re getting a little bunching back here? Just take and pull it like that and smooth it with your hand. Then you can put another one back here if you need to, but we’ve got plenty on here now. Some people don’t like to pad the foot very much. It’s not as important to have very, very little padding on the foot section, but it is important to have very little padding from the malleoli up through here because it’s the tightness of the leg cone that actually lifts the patient off the floor.
When you take your next roll and you come up through here, one is you’re nice and snug. Feel free to, like in this case, it doesn’t want to go the direction I want. Just tear it again. Some people refer to this as a herringbone style where you go, you know, top to bottom. You’re kind of putting it on like this, up and down, all the way around. When I get to the top, I find where my common peroneal nerve is. I’m going to mark that with several wraps of padding. And the reason we’re putting three or four here is, this is where a lot of people get irritation is the top part of the cast and in the front of the cast. And also, we want to have a lot of nice, thick material so that when we fold this down, it’s padded. And it’s below the level of the nerve. If you happen to put pressure on the nerve, you’ll find that you can get drop foot, or you can do some real damage to the nerve. So that has to be padded. So I’m going to put some gloves on and we’re going to put the material on the foot.
So I’m going to start with a three inch. There’s different sizes. There’s threes and fours. And this happens to be on all fiberglass cast. You wet the plaster and you do not have to soak it. One of the things we found is this stuff sets if you just leave it out in the air because of the moisture that’s in the atmosphere. So you only have to have a slight bit of moisture on it to have it still work. Okay, we’re going to go around the foot a little bit. And then we’re going to go to the back. I just do that to secure it so they don’t have to hold it. You do front to back. And as you come around, aim for the toe on this side, right? Go underneath and then come around again. Aim for the toe. And that’s about all that I’ll put on the end, and that’s because you can actually see through it a little bit, and it’ll allow the foam to breathe through to the outside.
All this has to do is protect the patient from just a light bump on the end. You have all the foam at the end, and you’ve got the cast material there, and it’s plenty to protect the patient without putting tons and tons of material there, but you can put it here. So now we’re going to take a four inch, and you want to make sure that the patient is at 90 degrees the whole time. So if you have an assistant, what they’re doing is with a gloved hand, they’re looking at the patient from over here, and they’re looking to see that they’re at 90 degrees the entire time. Now we’re going to come down here on the foot, we’re going to kind of lock the foot in, make sure we’re all covered back there, and we’re going to start up the leg. And I do get a little snug in through here.
This is where I want the cast to be tight. I want the material to overlap about 50 /50, and when I get to the top, right about where that nerve is, I’m going to end, and start coming back down a little bit when you put this on. Now, I didn’t wet that one. If you just take your hand and do this, which actually helps it adhere a little bit and helps smooth it, again, you’re making sure they’re at 90 the whole time. Your next roll is another four inch. Now we’re going to wet this one, and we’re going to take and pull this down to form a little cuff. Some people do it afterwards, some people do it now. I like to do it now and kind of lock it down, and then we’re just going to put enough cast material on it, just to hold it down, and then we’re going to start working our way down the leg again. and it’s gonna be snug in the leg section and now because she started to set up a little bit, it’s gonna be snug in the foot section too. If you have a very very heavy patient, you can incorporate what’s called a plantar plate into the cast, which is to take extra layers of plaster, our fiberglass tape, put it four or five layers behind the ankle and run it down under the ball of the foot and then put one more roll over the top of that to hold it all together and that that actually increases the strength of the plantar surface of the cast a great deal.
Now I always try to make sure I end on the outside of the foot and you like to have to see how it pulls back, you like to not have to stretch it at the very very end. Take your hand to smooth this down. Most of the modern fiberglass has kind of a built-in film that starts to develop when you rub it or put water on it and you don’t have to add anything extra to the outside to get it smooth. You then take a board and there’s a couple ways you can do it. You can either put the foot on the board and then come around and make sure they’re at 90 or what we do lots of times is have the the patient put their foot down, flat, stand up on their good leg with assistance and gently load this foot. They don’t pound down on it or put all their weight on it at all, you make sure they have light weight on here and all they’re doing is flattening the bottom of the cast. When she sits in the surgical shoe it has a flat bottom so that it’s not rounded.
It’s hard to walk on a rounded surface. If you remember before I said to make sure you end on the outside, these little corners of fiberglass sometimes kind of come loose a little bit and stick up and they’re actually very sharp. This gets very hard in about 15, 20 minutes and if you happen to be sleeping with your legs like where they can bump into each other, the cast will actually bump into the other leg and you’ll cut the leg so that inside the cast wants to be as smooth as you can get. Sometimes we have patients sleep with a stock in that on it or something so they don’t irritate their other leg. This stuff can get a little rough, these little edges here. Your job is just to keep it at 90 and smooth it up until it’s nice and hard.