Subtalar Arthrodesis for Post-Traumatic Subtalar Arthritis
Dr. DiGiovanni fuses the subtalar joint of a patient suffering from posttraumatic arthritis.
The video-article includes an Introduction, Exposure (via Ollier approach), Preparation of the Articular Surface (with emphasis on proper articular denuding procedure), Bone Grafting (autograft from proximal tibia), the actual Fusion procedure, Closure and closing remarks by Dr. DiGiovanni about the importance and future direction for this particular arthritic pain relieving procedure.
Main Text Coming Soon...
- Skin Marking
- Sinus Tarsi Approach
- Identify and Retract Peroneal Tendons
- Identify Subtalar Joint
3. Prepare Articular Surface
- Scrape Arthritic Cartilage
- Open Joint Space
- Perforate Subchondral Plate
4. Bone Grafting
- Identify Gerdy's Tubercle
- Harvest Graft
- Pack with Allograft
- Add Autograft to Joint Space
5. Subtalar Fusion
- Drill Through Calcaneus
- Measure for Screw Length
- Insert Screw
- Repeat for 2nd Screw
- X-ray Confirmation
TranscriptionsPlease note that, unless otherwise stated, these transcriptions have been auto generated and therefore we can not guarentee their complete accuracy
My name is Chris DiGiovanni and I am the chief of the Foot and Ankle service at Mass General Hospital, and I'm one of the vice-chairman at Harvard Medical School in the Department of Orthopedics. So my specialty is foot and ankle. The patient we're going to take care of today I've been taking care of for almost 15 years. He's a gentleman in his mid-forties and had a bad fall many years ago in which he sustained a very severe fracture of his heel bone, his calcaneus. So we put it back together back then. It was in many pieces and over the years eventually took his hardware out but healed everything well and since he damaged this bone and joint he developed significant arthritis. So he’s got post-traumatic arthritis. And today we're taking him to surgery to fuse his joint because he is no longer amenable to conservative management. We've exhausted all different means of trying to palliate his symptoms, and he can't tolerate this anymore.
So what you're going to see in the video today is we’re going to set him up in the operating room in a supine position, and we are going to then prep and drape is right leg. He has already been given some numbing medicine it’s what we call a popliteal blockade to numb him up after surgery so he’s comfortable and will give him some antibiotics. And then we will under tourniquet control make an incision that you'll see is sort of the initial step on the outside of his hind foot, so the subtalar joint is the and the calcaneus are two and atomic areas below the ankle basically the heel. He will I think appreciate what we're going to do today for him if he heals it properly because it's called fusion and that means we're going to eradicate his badly arthritic joint where all the symptoms are coming from and hopefully his cells will will bridge that with a bone, so that there won't be a painful joint there anymore.
So step one for us will be an exposure of the joint through a small maybe 1 inch incision called a Ollier approach. We're going to make sure we stay away from all the arteries and all the nerves and all the tendons that course very nearby once we get into the joint. Step 2 will be to clean out all the arthritis in the joint with curettes and and osteotomes and rongeurs. And once we scrape out all the arthritis our goal is to get it down to completely raw bleeding bone so that we can maximize the healing response. So step 3 will then be to drill up the surface what we call the subchondral plate and will do that with some drill bits. Sometimes we use an osteotome or a burr but today I think we'll probably use drill bits. And then once we've got all the surfaces rawly exposed and hopefully maximizes chances of healing it. Step four will be to go and take some bone graft to help him heal. So we can take bone graft from all kinds of places the hip the knee the leg the the the the ankle the foot even, but today will probably take it from his tibia which is below his knee because we need a fair amount of graft because of all the damage he did. So I'm going to guess we'll take between 5 and 10 CC's of bone graft from his tibia with a special device that is a bone graft harvester and then we'll plug that area close it up. And then step the five will be to put that graft into subtalar joint that we want to heal and prepare for hardware, and then the last step will be to fix the joint, stabilize it with a couple screws you can use staples or plates, wires. Today I think his problem is amenable to screws, so we'll put a couple screws in which is pretty traditional. And then and then finally we will simply close his close his wounds in layered fashion as long as soon as we're happy with what things look like on his x-rays. So we'll check his X-rays with a fluoroscan just to make sure we're happy with the hardware in the position of his foot. Once we are will close them up and then we'll put them in a splint. Then anesthesia will wake him up will put his tourniquet down and will bring him to recovery.
The whole process probably takes about an hour maybe an hour and 15 minutes give or take. And that's pretty standard I think and but but this this problem will take 3 months to heal minimum and a year to be at his best so it's a long healing process even though as operations go this procedure works pretty well. It's a good symptom reliever, pain reliever and it makes people a lot more functional in life.
So this is a fairly young gentleman, who about 14 years ago fell ten feet out of a window and shattered his heel, his calcaneus, back down and with Alan and we fixed his heel bone, his calcaneus, back then with plates and screws through this big big long incision. Traditional flap that we lift up to piece all the pieces back together like a puzzle. We have plates and screws and everything and he eventually healed that well and then we later brought him back to the OR and took all this hardware back out. So he's gotten a lot out of this. He's gotten 14 years out of it, but over the course of time because he damaged his heel bone and his subtalar joint he's developed progressive arthritis. So now we're going to convert his subtalar joint to a fusion. So we're going to scrape out the arthritis and probably put a little bone graft in and put some new hardware in to try to get him to heal that joint cause it's such a damaged joint has become very arthritic over a decade and a half and so that's what you going to see us do today. We could use this big incision, but I don't want to because it's a much more extensive approach and it's a lot more surgery and I don't think we need to do it. So we're going to do it through a much more limited exposure and try to accomplish the same task. So we're going to start with our exposure and we're going to be very careful because there are extensors and nerves here and there's a small sensory nerve in the peroneal tendons and the sural nerve here. So the Apex of this incision is defined by the by that anatomy, so that's where we're going to start. Starting this is called Ollier approach or a sinus tarsi approach, which is a good utility approach it's not an extensive approach but the nice part about it is that it heals well because it's in something called Langer's lines which are like the skin lines.
Two Sharp Sins please. Thank you.
So what we're doing now is we're getting down to the subcutaneous tissues. We’re looking out for sensory nerves. We are cauterizing all the crossing vessels and getting into this what's called the sinus tarsi. I'll take a self retainer please. Hold on a second. So. Sharp please. So this is the base of the sinus right here you can actually see quite nicely and it's all the ligaments over the top of the subtalar joint. There are several of them.
Probably take a bovie, and I would basically go in like this. Okay? Superficially and just be careful as you go inferiorly because you're going to have your peroneals nearby and that's probably them right there. Exactly.
So he's staying above his peroneal tendons, which is very important. Once he knows where those are this becomes a much easier procedure. He's basically going into the subtalar joint, and we're not quite there yet, going through a whole bunch of scar, but we're going to get there pretty soon. Okay now come out.
So you can see that this joint just barely moves. You can see it right here. Can have a freer elevator? There's the joint right here. Right there, there's not much left of it because it's quite arthritic but you can see the movement.
I'll take a right angle homen please. And then what we’re going to do is going to sneak around this. Slides right around just like that, and then you can really start to see the joint. So he's going to... I'm just going to free this up a little bit. Right in here. And then what we're going to do is I'm going to switch places with Dr. Moon, and he's going to put a very small curette in here and take down this joint.
There we go. There's the joint, or what's left of it. So just so Anatomy wise this is the talus, this is the calcaneus. He's going to be right between them in this joint, which goes in this plane and he's going to sweep back and forth to take out the the arthritic cartilage that remains. Just like that.
Do you have a large narrow tip? One of the OR 18 i guess. Stay in the plane of your joint. Keep going side to side. That’s it. Find your plane.
The key with the taking this joint down is not making a false track. You don't want to dig a hole. You want to stay in the joint, and it's it's easy to dig a hole if you're not careful and paying attention. So the joint is almost like to joint of the basilar thumb joint. It's sort of like triplanar that's where we call a saddle joint that goes up and over but it also contours the other way too. It's not just a straight flat joint. It's got several planes and you have to know where you are and you have to know your anatomy. Pituitary please. So you don't end up somewhere you don't want to be.
So you can see even though this joints arthritic you still do have a little cartilage left in it which is typically the case. Just because a joint’s arthritic doesn't mean there's no cartilage left. It just means that there's a lot less cartilage left and what's left isn't normal. So it's like it's like being on the surface of the moon where you have little craters you know peaks and valleys - that's what arthritic joints look like. There are areas where there are you know none in pretty good shape and areas where there in horrible shape but the problem is at the parts that are in horrible shape are the ones that make the joint painful. So even though part of the joint might be okay the part that's not okay is what the patient has problems with. And we don't have a good way yet in life to put all the cartilage back. We're working on that lot of labs are working on how to put cartilage back but we don't have that technology yet to any significant level.
The other complexity for this joint is that you can't replace this joint. This joint is not... Be careful with your structures down here. So unlike an ankle joint or hip or knee or shoulder you can't just replace this joint. This joint is not replaceable yet, we don't have the technology to do that. We tried. I've actually I've actually designed a subtalar joint replacement years ago but that did not work well and others have tried and hasn't work well for them either. So this joint is biomechanically complex and it's also it's subject to tremendous forces you can imagine the whole body has to pass to put weight on this little joint so it's asking a lot of a tiny little area, which is why joint replacement of this does not do very well. So we don't have the luxury of just taking a arthritic subtalar joint after a bad heel injury like this gentleman had of just putting in a new joint so we have to fuse it. It's the only it's the only option we have that works very well. And it's a very good operation. It limits the motion because the the joint no longer moves but it's a very effective pain reliever. So as long as the patient heals this it usually will last them the rest of their last the patient the rest of his or her life. And what usually brings them to the operating room is not stiffness even though they don't like to be stiff. What brings him to the operating room is pain. So it's the pain that you want to relieve.
Now he's getting all the way to the side of the joint. You want to make sure you get the whole all the residual cartilage out any arthritic areas you want to have basically to raw bony surfaces. That's that's the goal here cause that will maximize the chance of of this healing. Fusing.
No. So this joint is a very big joint too, so it's not only anatomically complicated. It's also fairly large so just when you thought you'd gotten it all usually you haven't. And it gets way in the back here so you have to take the time with this joint cause it'll fool you. Suction please.
So here are the peroneal tendons right here. The sural nerve is probably right in here. and we're going to get reflect those out of the way and so just so you guys can see well in here there's the joint right there. you can see, see the space. Freer please. So to show you what we're working on here this is the joint right here. Right in there.
You can see how far back it goes you put this back there it's pretty deep and we're not even all the way to the back so. But we're close.
This is a great lamina spreader best one they make don't leave home without it. It's... You can't do foot and ankle surgery without this instrument. So we put this between the lateral process of the talus which is right here and the anterior process of the calcaneus which is right here. So it goes between here and here, and we're going to try to open this joint up a little bit. And that opens it up somewhat and I'm going to let him come back in here.
So when arthritic joints typically get tight cause they get stiff they scar so sometimes you have to use little lamina spreaders just to get in there. So self retainer back please. Now you can see the joint even better. Okay I'm going to switch places and let Dr. Moon go at it.
So one of the keys of surgery is being efficient, so once you have an exposure you want to take advantage of it cause you don't want to pull too hard on the skin or the soft tissues. So once you give somebody exposure they need to quickly do their job, and that way you're not irritating the soft tissues of the skin too much which is important. Now we're going to irrigate this joint up a little bit. Just to flush everything out of here. Sometimes as you're working all the stuff gets caught up in there. So he's going to he's going to put that in there and just flush it all out. Sure. It also irrigates the tissue so the tissue doesn't desiccate, what you don't want to have happen right. The only common denominator to all living things is water.
Now can I see my larger lamina spreader please. Now maybe we can get the larger one in there. How's that? Once we're done with this he's going to take a 2 mm 2.5 mm drill bit from my set with a guide. You don't have to give me the same guide, least give me a guide that's pretty long, not necessarily the guide that fits the drill bit, to protect the soft tissues. And then we're going to drill this up.
So I think it Dr. Moon pretty much got this joint. It's looking pretty good here, and now we're going to do is going to prepare this for fusion.
Okay, now I'm going to switch places with him and he's going to drill this up. He's going to carefully protect this tissue down here with his drill. That's what the drill guide is for. I call it soft tissue protection sleeve, and he's going to drill multiple holes across The joint to perforate the subchondral bone, subchondral plate. And what this does is it improves the blood flow to the area to maximize the chance of this fusing. it brings blood to the area. So it just makes a whole bunch of little holes, all across the joint. So if you look in there you can see all the little pieces of bone graft, and that's the goal here is to perforate those holes.
Now we're going to try the other side of the joint. You don't have to use a drill bit this big sometimes you can use a smaller one. This is a 3-2 drill bit sometimes I'll use a 2-0 or 25 basically will base the size of my drill bit on the size of the hole. You want to be careful when you going in this direction cuz the neurovascular bundle is over here. So you don't want to plunge because that's where the arteries and nerves are. So you want to be very cautious over here. We really mucked this up and it looks good but now what we're going to do is take a little bone graft to fill that.
So we are underneath the knee joint. This is the kneecap, patellar tendon. My thumb is right on the knee joint. This is called Gerdy's tubercle. This is the insertion of the tibial tubercle. Gerdy’s tubercle is right here. We're going to go right over this to take a bone graft from there. Fibular head is over here so yeah I cheat a little bit anteriorly and below the knee joint because you don't want to be in knee joint. I'll take two sharps sins please. Probably one of the bigger ones. What's that. Medium or large. Put your finger right in there. Probably going to use this one on power.
So we're trying now get right down to the periosteum below the knee joint. So there's the knee right here, we're going to come down. There's where the tibia begins to flare out and this is the gerdy's tubercle right here, so we're going to go pretty much right here. I'll go straight to bone. Again I always check my knee I think I'm fine. And then we’re going to take a little bit of this. We’re just going to free this up just a little bit so we can get in here. There we go. Okay that’s pretty good. My knee joint, again I'll check that to make sure I'm okay.
And this is something we design to take bone graft so we're going to put this right here. We're going to aim it away from the knee joint. Just like that. You want a few centimeters just like that and then we basically break it up. Then we turn it back on. And you can see it takes a whole bunch of bone graft very quickly then you take this off you don't even have to take your hands off to put it right in here and you go like and you got to graft. So we design this it's a neat little technique for a dowel. Takes 2 seconds. Okay. There you go.
We’ll take some irrigation. So here's the hole you see we're outside the knee joint completely, and that's our hole. We’re going to take a little irrigation. Now we’re going to pack this because we take a fair amount of graft I like to pack this so that there's no stress riser here. So we're just going to irrigate this. We could obviously take a lot more graft, if we wanted to. You don't have to. So there's our hole. That's how deep our hole is. It's right in there and so you can actually look right in there. And it’s just a neat little technique. So I usually put a little saline on here because it makes the bone stick together. So we would pack this in and we just back fill it so it's no stress. Doesn't become a stress riser.
So basically we’re filing this with allograft, which is cadaver bone. Cadaver bone is good bone human bone but it doesn't have cell it doesn't have this cellular or proteinaceous contributors to healing and his graft does right. His graft is still alive so it's got cells in it and it’s got all the growth factor proteins and everything so we're taking that and putting it where we need him to heal and this just acts like a filler. This is a great place to get bone from it's safe, it's quick and you can get a lot of bone. I can get three or four times as much bone as I took out of here if I wanted to, but I don't think we need it but if we did I could get it out of this hole.
So now he's just going to gently tamp that down. So that it's almost as if we weren't here. yeah maybe a little bit more just a hair more there and I think you're good.
So we took out about probably eight cc's of bone graft for putting in probably 8 to 10. So you took out his own autologous? We took out autologous because that has the protein and the cells and all the things that are good for healing and we're putting in cadaver bone which is just structural. There's no cellular... There's minimal there's no cellular in there's minimal proteinaceous support with this. It's all been treated. It’s all treated bone but we don't need this to heal necessarily. We just need this is as filler. we do need a subtalar joint to heal so you don't have to use bone graft. We've written some studies actually in publish them recently, with level one evidence, showing that you can also use other types of things like Augment which is were recombinant platelet-derived growth factor PDF and trichem Faded tricalcium phosphate which works as well as his autograph does. Now you should Tamp. I would tamp that in before you… Otherwise you get it on the soft tissues which you don't want to do. There you go. 6 5’s. I'll take my freer please. So I don't like to get any bone in the soft tissue. Bone is not designed for the soft tissue. Bone is designed for bone. So I'll try to clean all that up.
That looks pretty good and then we're going to take that gel foam please. As a gel foam this is like a hemostatic agent but it's a great filler so I put this right over the top form fills to this defect and literally sits right over the top just like that. It's a neat little trick. And then we'll close that with some vicryl. Thank you. 2 sins please. Yep. Yep. Now he's closing the fascia right over this. Sponge please.
Good. So that's all closed up now, and we will deal with the rest of that later. Now let's go back down to where the action is. While my fellow’s doing that I'm going to make a little incision here for him so that we can put the screws in. So this goes right to the base of the heel.
Right to bone. Yep. That's where we're going to put our hardware. Alright So he rongeured up the bone graft, and now I'll take my wheetie please. We're going to... I'm going to have them put all this in here now. So now he's going to put all that in. I'll take a Freer, and all this graft gets shoved in here. Pack it into the space the space is going to get compressed by the hardware, but we're going to shove this graft in as a way to enhance the healing response. Can I see that the rest of that morselized allograft as well? We will use that too. Got it, mind as well use it. It was delivered. Exactly. Exactly. You want the cancelas. Alright, so he's got lots of graft in there. Alright.
So now what we do is we hold this up and we basically and… I just went in a hair and then I'm looking at my joint. So kind of like that maybe, 45 degrees. So I wrap this. This is just something I like to do, because if the metal ever hits it it automatically puts a hole in the drape. Unfortunately is coband is not long enough, second one more Coban please. The metal won't usually poke through that but if it hits the plastic it'll pull through almost immediately, so this is just an adaptation I like to do, I call it insurance. Okay.
Alright that looks about perfect. That is in the calcaneus. It's about to go across the subtalar. So now we're going to go across the joint. Now I go into there. There. Now I take a feel in my ankle to make sure my ankle feels good it does. Now let's check it. Okay now we're going to get a AP ankle, and that looks perfect too. So you can see that in the ankle not going through anything. It's in a perfect spot and now I'm going to have my fellow, Dr. Moon, put in the next one. And it's going to start about a centimeter away, which is why some people like cannulated screws with guide wires. I just use screws, drill bits rather. so he is going to start a centimeter away and then he's going to sorta of stay parallel but angle a little bit further distally in a little less looks pretty good right there. He should feel it go in, once it crosses the joint. Now he’s is in the talus. Right. So you can go a little further if it felt good. Go little further, if you’re in talus. Are you in talus? Okay. Let's take a look. That's going to be perfect as well. I like it. That's perfect.
Okay. so now the same thing. He is right at the subtalar Joint. Now is going to advance to the talus. Yep now he's in talus, goes about a 2-cm. Yep. I think you can go further. No we're using 654 regular from the large frag. Okay. Let’s check that. That's ideal placement. Now let's get an AP. Try that. That looks good too. Save that. Those are both very well placed. The talus is a medial structure so you want these a little on the medial side. I’m going to put the first one in and he's going to put the second one in. Thank you. These are nice pliers because they're easy to use. So basically I grab this, I keep my eye on what I'm doing. I pull that right out and I run my depth gauge in like that. These are usually 75s. This measures 76. That's good. So we're going to take a 75 please. 75mm.
Okay and then what I do, again you can use guidewires if you want, but I'm not a big guide wire fan. I think if you know the anatomy this is actually faster. So you jiggle it, find the hole, and then just turn it. Don't angle it, just turn it. Once you get to the skin you got about a centimeter to go. So we’ll go right there and then we're going to stop and then I'm going to let him do his. He keeps an eye on what he's doing. Yep, he's got a big hole there. This should be slightly longer probably like 85 to 90. Its measuring right now 80mm. Huh that's probably going to be OK. There’s his angle. He just touches it. He doesn't aim it. He just turns it. He's only got one hole. The screw finds the hole. and he's going to go tight to where mine is. Then we’re going to check the X-ray. If the X-ray looks good and will just send them home.
Alright let's take a peek. Looks good. I like it. Okay. Once you get underneath you want to be careful not to over advance this once you feel resistance you stop, like right about there. Otherwise you'll drive it right to the calcaneus and it's a subtle feel. It's a feel you have to get used to, but there's some subtle resistance. And that's all you need. Let's take a peek. Yeah ready. That looks great. Let's print that. I like it you can see the we put all the bone you see the joints gone. Now let’s get an ap ankle. That looks good too.
Alright that's all she wrote. Okay so that you can see those two screws in nicely in the ankle. We're going to close him up.
I'll take some gelfoam please and some irrigation. So first we irrigate this out. Then we're going to put some gel foam in here. So I take a piece of gelfoam, which I really like to hold graft in place and I'm just going to shove this in here to keep on my graft where I want it. It just sort of keeps it all in place. Nice, nice and clean.
So we're going to close this in layers. He's going to grab a deep layer there of fascia. Yep and he's got it. Yep. That's his deep layer of fascia over the sinus. He doesn't want to grab too much. He's got a perfect amount so he doesn't get into the peroneal tendons, cause then I have to hurt him and I don't want to do that. He’s a very good fellow.
I’ll take a suture scissor please. So this closes it nicely and seals it up well to get a nice tight seal. This patient will take about three months to heal. Good. And he'll go home today. So there's our closure.
Can I have the 3-0 as well? One of the nice things about this exposure when I was talking about Langer's lines before is that as you dorsiflex the foot and evert it relaxes the skin you say so it makes for a nice nice non-tension closure. The heel is in the neutral position, which is about 5 to 7 degrees and valgus and about 10 degrees of external rotation roughly. So it's very important to keep the heel in a neutral position because you line up what you call your mechanical axis for weight-bearing. Now fortunately we fixed his heel years ago 14 years ago when he broke it and then later took his hardware out so that made this better because you didn't present to us with a terrible malunion which is what happens if you don't fix these so then you’ve got to not only fuse the subtalar joint you also have to revise the entire heel and those can be even trickier. We just close this with a little running stitch.
We're not going to forget the heel. So I usually like to make sure these are not too tight. I like loose loose stitches. Alright so that’s it. So we're going to splint him and let him go home today. Okay.
So we finally... we just finished my patient’s procedure and I think the game plan was as anticipated for the most part. We ended up putting two screws in and about 10 CC's, 8 to 10 cc's of autologous bone graft, which is bone from him. And he's on his way to recovery. It was very uneventful. It was a little his joint was quite stiff, which is not all that surprising because when you have post-traumatic problems like his things tend to scar in a fair amount so we had to remove some scar to get in there and his joint was also pretty arthritic so I think this was a good choice for him. It was not a very functional joint, and I'm sure it was pretty painful. We've got high hopes. I'm anticipating that he will heal this in 3 or 4 months and then we can advance him out of a... so we're going to start them in a splint we will then transition him into cast probably for 4 to 6 weeks and then will transition to a removable Boot and then hopefully by 3 or 4 months if things go well I'll have them in a sneaker and back to regular activities and hopefully some exercise. And and I'll continue to follow him along.
Subtalar Fusion is a time-tested operation. There are a lot of joints in the body that we can replace with joints like knees and things that hips things like that you cannot do that to the subtalar joint. It's a very important joint. It's one of the essential joints in the foot. And it is responsible for side-to-side motion like walking on cobblestones or beaches or uneven surfaces, unlike the ankle which is up and down motion. So it is part of a very important joint complex, so we don't like to fuse these joints we'd rather replace them. It's just that we don't have replacements that work well. We’ve tried them over the last hundred years they don't work well they still don't work well. and I don't envision it time at least in my lifetime whereby we will have a successful joint replacement so for now fusion is the gold standard. It does work very well. It makes them these patients a little stiffer, but they're also much more comfortable for standing and walking and doing things routine activities.
The indications for subtalar fusion are many. Patients can have congenital abnormalities they're born with, deformities they can be born with, what's called tarsal Coalition, which is when two joints are two bones are stuck together and they're not supposed to be. Patients can have bad injuries like this gentleman with fractures around the ankle or the foot for that matter and end up with debilitating problems and significant dysfunction. And Subtalar fusion is a nice way if the joint’s really damaged to alleviate a lot of the symptoms of come from the damaged joint. We have done this operation for people with infection. We've done it in patients who had prior surgery that did not work well to salvage the joint and mitigate their symptoms. We've done it to realign bones or foot deformity like excessively like flat feet or conversely extremely high-arched feet. So this operation really bridges many different pathologies in the foot and ankle in is a very effective operation.
Contraindications are not many. If a patient has an active infection or a significant soft tissue compromise whereby we're worried that we will not be able to do the operation and have the patient effectively heal from it without problem then we will not do the operation, or if a patient is sometimes a very unhealthy host and wouldn't tolerate surgery in general that's another contraindication to doing this. Nut by and large they aren’t very many contraindications for this in patients who really require it.
The most important to things about this operation three really is one is getting in safely and getting out safely to make sure you don't do any iatrogenic damage to the patient. Secondly would be making sure you maximize the chances of them fusing the bone so we published multiple papers on how important it is to get a fusion and what it requires to get a fusion and obviously if it doesn't fuse then you have to start all over again. So you don't have full control over that as the surgeon and the patient doesn't have full control over to the patient but it's a team effort and we have to do a good job. The patient and has to take good care of it and of course they're their cells and growth factors that circulate naturally in their system have to do their job as well. But assuming all things those things can happen it will usually be effective in between 80 and 100% of the time, so the non-union rate for this operation is about 10% but those odds are still pretty good by orthopedic standards.
There really is no alternative to this operation if you have a significant hind foot problem that involves this joint. This is really I mean there are different types of ways to do this with foam blocks and realignment osteotomy and things like that but the act of fusing this joint in it of itself is a really a a gold standard for this for this part of the foot anatomy. It's a very important part of the foot because you bear all your way through it.
So another important thing about this joint is getting the alignment correct that you must you know so if you want to do it safely you want to get them to heal but you also want to correct their alignment or maintain good alignment if they start with good alignment, but to get them to heal and in a bad position is is is no more better than having them not heal at all. So all of these are things that we need to keep in mind over the course of the operation so if there's a lot of art to this as much as there is a science to it.
Sometimes you do this operation arthroscopically so I think the last one I did which was a month ago we did the arthroscopically so we do tiny little incisions and we just go in and scrape it out with a little camera and then you can do it that way too, frequently we do. This patient was not amenable to that because he had bad trauma to his full of scar so that this would have taken a long long time and that's probably not the right choices of technique to fuse him. So we did him through what's called an open approach with a standard incision and an open exposure but these can be done arthroscopically they work pretty well the risks are low are the recovery's reasonably quick. It's just that you have to pick the proper patient for them. The only other thing that I do and I don't think anything I do specifically is unique there are a lot of tertiary foot and ankle specialist to do this operation in there I know in their office, and I but we often use bone graft so I'm a believer in some type of graft. You can either use the patient's graft you can use allograft, which is cadaver bone, or you can use something called augment, which has recently been FDA-approved. Aside from what I have mentioned there are no immediate earth-shattering technologies on the horizon that I'm aware of for this particular joint.
I think that it would be nice to develop a joint replacement for this joint, but we tried to do that already ourselves in our own labs and it's just this is a very anatomically complex joint, one of the more complex joints in the body. And it does so much work per unit area right. It's a small joint and it bears all your weight, so the force per unit area or the oval stress that go to the series substantial and so you have to be careful with it and and respected for what it is and what it does so in the immediate future I don't see any major changes in the on the horizon though. I think that one or two things may evolve in that is either a the ability to replace the joint with metal or plastic or replacing the cartilage. So you take a gentleman like this instead of fusing his joint because he has bad cartilage maybe they'll be away in the next 20 30 40 years where we can simply resurface his cartilage to give a new cartilage. Those are things that I would say it will be on the horizon hopefully.
So I didn’t use cannulated screws a lot of people prefer them and because you can put guidewires in in this follow the screw over the guidewires. I like I feel like it's good for fellowship training to teach these guys how to really memorize their anatomy and learn it well, so I don't let them use a cannulated screws usually. I let them use a drill bit so you sort of have to think exactly about where you're going and get it right, but the advantage of that is it once you get comfortable familiar with that it's actually faster more expeditious procedure. So we basically position screws to go up through the heel bone the calcaneus and then right across the subtalar joint and up into the talus, which is the bone inside the ankle. And you know it can be tricky but you know when after you’ve done a thousand of them you sort of getting used to them and and you have to very what you do little bit with the anatomy depending on what their anatomy. His anatomy was not normal so it made it a little trick here for us, but but you have to make sure that you your screws do not go into the ankle joint for example which is probably the biggest risk or to exit the heel bone where you have all the arteries and nerves going into the foot. Those are the two danger zones that you have to be careful to avoid.
In a place like this where we see patients from all over the world we see lots of interesting and unusual pathology and there are lots of things that are off and unexpected that were forced to deal with but that's part of our job. For this particular patient, I've been following him for a decade in a half so I did not have any surprises in the operating room today, but I wasn't expecting any either. We've treated hundreds and hundreds of patients with bad traumas like this who end up getting this joint fused in a similar fashion. So while at the same time we like challenges and we like interesting unusual cases and complex things to do it's also nice to have some relatively straightforward things as well without surprises today, so it's nice to have a mixture.
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