Board Review Surgery

Mini-Fixators - When and Why

Marie Williams, DPM

Marie Williams, DPM describes her experience with mini-fixators. Dr Williams also reviews multiple cases where she utilized mini fixators and shows how they have been beneficial to her patients.

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Goals and Objectives
  1. Understand uses of mini fixators
  2. What the advantages are to using mini fixators
  3. Understands the applications to mini fixators
  4. Understands complication and contraindication to mini fixators
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  • Author
  • Marie Williams, DPM

    Director, Podiatric Medical Education
    Aventura Hospital and Medical Center
    Aventura, FL

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    Marie Williams has nothing to disclose

  • Lecture Transcript
  • Male Speaker: Marie Williams has been on our platforms for many, many years. Board certified obviously in foot and ankle surgery. Fellow in [indecipherable] [00:09] foot and ankle surgeons. Very much involved in counsel and teaching hospitals, residency director in the South Florida region. Today I ask Marie if she would give us her thoughts on mini external fixators. We hear a lot about circular frames, pin-to-bar, and all the big guys. Sometimes we forget about the effectiveness of many fixators. So please welcome Dr. Marie Williams.

    Dr. Marie Williams: Thank you. Let me make sure I have this right. I’m actually going to talk to you about mini ex-fixators and where and when you can use them. The important is that there are some advantages to mini ex-fixators that I believe I’ve been using for a very long time. I’ve been using them in every form of the forefoot and midfoot and ankle. I want to kind of go over that indication. For the most part it’s for an open or close fracture with significant soft tissue involvement. The construct engages the soft tissue away from the trauma. So you want to make sure that one of the nice things about a mini ex-fixator or any ex fixator is you do not have to deal so much with the soft tissue injury. At least when you see a lot of swelling, this might be a good alternative. Polytrauma, it helps in the anatomical stabilization with severe trauma. As you heard earlier and I don’t want to repeat whether it’s a mini ex-fixator or it’s a large pin bar or a circular frame. What you’re doing in polytrauma is actually sometimes just stabilizing your area for further procedure. It’s minimally invasive. It does not usually invade the vascular structures. You can use it for arthrodiastasis, arthrodesis, and also articular fractures which is poor stability across the joint. It can permit early range of motion. That’s one of the things that I use in calcaneal fractures because I can get ankle joint range of motion with the mini ex-fix. It is also good for distraction osteogenesis to restore osseous deformities. We’ll talk a little about that in a few minutes. Indirect reduction of the fracture fragments. Also are good to stabilize the position of the potential fixation. In the foot specific indications is for callus distraction. This raise arthrodesis, Charcot arthropaty, fracture dislocations, and fusions. Some of the things that I like to talk about a little bit, touch up on everything that I can, but breaking metatarsia is one area that we use callus distraction or the brachymetapodia. You can see here that when you do brachymetatarsia, it’s important that you put the pins in first on the 5th metatarsal. I’ll go over how you lay the pins but you’ll put them in on the lateral side of the foot. Then you make your osteotomy before you put your fixation device on. Key is put the pins in first, then make your osteotomy. We’ll go over that. Some of the pros of callus distraction. We have less dissection on soft tissue. Also you can have your soft tissue adapt when you’re doing a lengthening type procedure. There’s less joint stiffening. Less risk of a chronic or a lower extremity edema in the area, and some less risk of neurovascular compromise. Some of the disadvantages or the hyperthropic scarring that may occur. When you have the patient is very dependent sometimes with callus distraction and with the job of making distractor become more advanced, then sometimes they can get very involves so much that they decide that more turning is better. Sometimes that’s not how you want it. There’s also pin tract infections and pin loosening which can become a problem, and also joint subluxation. So you have to understand that patient education is very important especially if you’re doing a brachymetatarsia with callus distraction. Some of the surgical approaches. Remember that in these metatarsals, dorsal incisions, maybe indicated over the metatarsals and the cuneiform and the cuboid. Also the length of the incision is dependent on the size of the metatarsal injury. Dissection is usually taken right down to bone and avoid a lot of soft tissue problems. When you do a lengthening procedure, you have to have be aware of the extensors. Also that there’s no need to lengthen extensions especially if you’re doing a slow progressive lengthening.


    The periosteum maybe in size creating a small envelope which allows you to actually help with the lengthening procedure. Some of the periosteal dissection is definitely surgeon choice or some literature out there that states. Less periosteal dissection helps to give more nutrition to the bone. That’s not. I don’t know of any article that says pro and con or if done any research or studies that show one is better than the other. So we call that surgeon preference. Pin placement is important prior of course to the osteotomy. The distal pins are usually placed first. Then the external fixators used for how much or how long you want that osteotomy or where you’re going to put the proximal portion of the external fixator. Then the pins will guide the placement of the external fixator. I actually place the proximal pins percutaneously after I’ve done my initial dissection. Pin placement is also very important when you talk about metatarsals, usually on the medial. The 1st metatarsal, the pins are medial. The 5th metatarsal are through lateral. Then the metatarsals 2 to 4 are placed 45 degrees and I’ll show you a little. This is a good picture that just shows how the pins are maybe placed for callus distraction in the frontal plane. When you actually do a diastasis procedure, you’re in a diaphyseal or distal metatarsal area of bone and you want to place the osteotomy so that you do that, put the pins in first. Once again, I reiterate that. Then make your osteotomy for your lengthening. Here’s a patient. A 16-year-old female with bilateral brachymetatarsia of the 4th metatarsal. You can see here where the pins were placed approximately 45 degree angle. Then the lengthening process was – this is three to four weeks post lengthening. At first, when you first put this external fixator on, what you do is you actually, for one, we keep it closed. Then you’ll start to distract out, and you’ll distract out a quarter turn off four times a day so you’re getting a centimeter of length each week. You’ll end up seeing the distance at which this starts to develop. Now what’s scary for me when I actually did this initially, you’ve seen that big large space of empty bone, well that’s actually not empty bone. Bone is filling as it’s lengthening. The nice thing about that is you don’t have to worry so much about the soft tissue. We used to put in bone blocks. You don’t have to worry about distracting too much or going too fast and having a neurovascular compromise or a neurologic problem or maybe even a tendon problem. Here you’re slowly distracting overtime. One of the complications to this, and I’m going to just back up for a second. In one of the pictures, you can see a K-wire holding the toe in place. I recommend that where you’ll actually put it into the proximal phalanx and digit so that that maintains the joint. But in the opposite foot we didn’t do that. So the patient kept turning and turning and turning. All we did is we ended up having a subluxation of the metatarsal at the level of the metatarsal phalangeal joints. The lengthening was too long. So now you’re not in any trouble at the moment. What you can do is now take your external fixator. Instead of lengthening it, you can now bring the metatarsal backed. That bone is still spongy and soft. So what we did is we actually turned it back to turns, brought the bone in better alignment and then left it there and left it intact for another couple of weeks. Of course this is a non-weight bearing procedure but an excellent procedure for slow lengthening. Here’s another way that I’ve used. Pin-to-bar systems and mini ex-fixators for Lisfranc incjuries. You could see here this is actually a Lisfrancs. Pretty destructive. A lot of soft tissue swelling. So in order to stabilize from the soft tissue swelling, I particularly like the pin-to-bar system. I’ve been using the pin-to-bar system since 1994, maybe even earlier, where I used the Hoffmann system to actually stabilize fractures and then reduce the fracture and then go back in later and do an internal fixation as needed. Charcot neuropathy. You’ve heard all this with pin-to-bars and ring fixators. What I’ll do is use this pin-to-bar system. This is a stealth frame. It’s actually a good fusion type frame. So you might want to jump right to fusion with these types of patients and put a pin-to-bar system in like this. This is another option. You can see here it’s both medial and lateral and it provides excellent compression in the diabetic who has very – the bone is actually somewhat – I call it a brittle bone but it actually is very hyperemic.


    So you’re actually losing a lot of bone. Sometimes it doesn’t afford the internal fixation initially that you might want to use. So I’ll use this external fixator for fusion stabilization. Calcaneal fractures and all types of fractures. I love these little mini bars. Some of the things you can do with these and I’m going to show you. I actually create a lot of different – I feel like I’m back in the thinker toy days or building up linking mods or something when you play with these bars and pins and things. This is the lateral side of the calcaneus where I can get full distraction with this small little system. Here’s another pin to bar system where I’ll use it through to through, both medial and lateral. And then sometimes I’ll just go lateral. It depends on the type of fracture. It depends on how much deformity there is in the metatarsal itself. Here’s an example of a talar fracture which is fairly culminated. You that the rule of thumb is talar fractures and talar injuries don’t do well. So my idea is if we could actually stabilize the fracture, it has less trauma and we do less soft tissue injury by not opening these up. So what I’ll use is a pin-to-bar system to stabilize the fracture and I’ll use a triangular construct so that I can stabilize not only the CC joint but the talonavicular joint and also the talar joint. I’ll use pins simply to stabilize the fracture and then use the external fixator for distraction and stabilization. Here’s an example of a severe dislocation, a talar dislocation which I actually could reduce on the operating room under anesthesia. So I never needed to really open that patient up. So what I did is I used small. I used K-wires to stabilize everything and I use this small triangular external fixator in the talus. I stabilize not only the mid foot and the rear foot. I’ll show you a picture of that as well. So that this way we didn’t have to open surgically the soft tissues. I was lucky enough to get the fracture reduced well enough to stabilize it. Then this is of course a non-weight bearing type process. But I can get early active range of motion around the ankle joint which is what I really liked about this type of construct. It was very stable. You can see here from dorsal to plantar. We were using these small pin-to-bar system and the K-wire stabilizing all the fractures. Here’s an x-ray of that where you had really excellent alignment of the talonavicular joint and the calcaneocuboid joint, then the triangular construct to maintain stability. It was just with simple pins and bars. This is an example. I show this because there’s two pictures. The patient. I don’t know if it’s your left or my left or right. But there’s one where there’s a small scar and the other isn’t one. It’s a bilateral calcaneal fracture. I like showing this because the one area where we didn’t fix the calcaneus that we left alone, he had significant increased pain and deformity years down the road because he had more valgus to that foot. The side that we actually stabilized the calcaneal fracture got linked to the lateral wall and put the heel in a more anatomically normal position. Even though we didn’t have complete reduction of the subtalar joint and the lateral foot, he had less pain because his heel was more stable to the ground. That’s just an interesting point of view because when you look at these calcaneal fractures, really ultimately if you think about it, whether you use plates, screws, pins, bars, it doesn’t really matter. What you’re trying to do is realign the calcaneus to be more anatomically normal, more perpendicular to the ground. You’re trying to decrease the lateral blow out. Less peroneal injury. You’re also trying to get this sustentaculum tali aligned and the posterior facet brought up. So if you can achieve all those with your pins or your plates, you’re doing a lot better off for that patient than just leaving it alone. Here’s that patient where interestingly enough what I always do is I mix this pin-to-bar system especially with the sustentaculum tali and also the posterior facet. I’ll take the freer. We’ll lift the freer, use the freer to lift up the poster facet. Put a pin in there or a screw in there to hold up that lateral wall to the sustentaculum tali, and then stabilize with the bar system. Here’s a calcaneal fracture that’s fairly comminuted. The key on all of these, they don’t look any different from my patients and anyone else’s patients that have calcaneal fractures.


    The lateral wall is always blown out. You can see that here. One of the biggest complications that you have is the fact the lateral wall is blown out. You have peroneal problems and sural nerve problems as well as the fact that you have subtalar joint arthritis. That actually will ensue. You have a joint depression where the sustentaculum tali and the posterior facet and the middle facet are now compressed into the calcaneus which need to be lifted up. So what I’ll do here is a picture of actually a very percutaneous type procedure where we’re lifting up the actual facet itself. Then with a cannulated screw under C-arm guided, we’re actually fixating the lateral wall underneath the posterior facet into the sustentaculum tali. That stabilizes that joint somewhat. Then with a small external fixator, I’ll actually then put the pin-to-bar system. What I do then is I’ll get length with that. I can actually -- with this system, you can actually pull the pins apart some and put the bar on and you’ll get distraction as much length as you need. Then I also keep the ankle joint free. So I have ankle joint motion. I’ll have the internal fixation with the screw fixation along with the bar stabilization. You can see it here and then here is an example. Again, I’ve got the same patient where there’s very little soft tissues swelling, very little impingement on the peroneals. The screw is actually holding up the sustentaculum tali with the lateral wall. This patient went on to heal very well. They don’t have to go through all the – they can go through full range of motion in the ankle joint which I like and we keep them moving as much as we can without good stability of the fracture. Mini ex-fix with open wounds. Now that’s kind of a bit of a crazy concept although we’ve seen it here today when I started doing this. People were like you’re a little bit crazy for doing this. Here’s this patient. He came in. He had a subluxation of the calcaneus and the talus mainly due to a complete osteomyelitic breakdown of the bone from a compression, from a pressure wound laterally. Which ended up with significant infection. The only thing I could think of besides leg amputation is to actually debride out some of the talus and the calcaneus but what I had left I needed to keep stable. I felt that if I could keep that wound stable and I could keep the bone stable, I can heal the wound and have him with somewhat of a normal foot where he could be braced and ambulate. So what I did is I used this pin-to-bar system because I felt that at least with the small pins we could stabilize the bone. Although we knew he had an infection, I know that it’s kind of – people go, “Well you’re putting that in an infection.” We had the infection. We debrided it. He was on antibiotics. He had antibiotic speed [phonetic] placed in there, and then the bone was fixated. It was done in a three or four surgical setting. So you have to understand that we didn’t just stick this in a pussy infected necrotic bone, but once the bone looked a little bit cleaner, although we knew we still had a – it was bio-burdened. And then I stabilized the bone itself. Then this is him actually a month ago on the one side. I think the green is the pointer. This is about a month ago. Then this is just the other day. This one acted full healing. I’m going to go back for a second because here in this wound, this is about three months ago, four months ago, and I had to stabilize everything. I kept that on for about – actually it’s about five months. I kept them on for about two months. We just hold everything in place while the wound was healing. Now interestingly enough on that wound, I could do wound care, any type of wound care I really wanted. They key was that I was stabilizing the foot so that the wound could heal. Then you see here. Now he’s technically healed really with a small pinpoint wound there. Now he’s going to be putting a [gauntlet] [19:15] type brace or a crow walker or something to stabilize the foot even more so that he can ambulatory. It’s important that this man walks. He’d been bedridden and debilitated for so long. Dialysis patient, diabetic, the whole gamut. Here’s another example and this is a little bit bigger than the mini ex-fix but I like to show this. I probably wouldn’t have if I knew everyone was showing their little pin-to-bar systems. We put a kickstand here and I think that’s really kind of a take home message. You can use these systems in any way you want. This was use to offload a wound and to do wound care. Here’s another one where he had the wound on the anterior aspect of the leg with the tendon exposed and he had a Charcot foot. But the reason why we put this type of system on it is so we can get to the wounds and do wound care.


    To me, that actually aids your healing and your ability to treat the patient so that you’re not forgoing the wound for the Charcot. This is another example of a pin-to-bar system in a patient who technically was not a really good candidate for an open procedure with a plate. So we use the mini ex-fix to an arthrodesis. Just another example of how you can do that. This is a good system where you use these small rails where you can actually put in on and then put it at the tension that you want, compress it and then just leave it there. So this is just a different type of a concept where you’re doing the actual pin-to-bar system for arthrodesis. Here’s another patient who had both internal and external fixation. More stabilization of the fracture site, the toe, and also the joint itself. Remember our minimum insult to the vascular supply? It avoids direct contact with the [periosal] [21:16] capillary bed. It also has a minimal soft tissue interference. So you have a little bit better advantage when you have soft tissue injury. Again, it can correct osseous defects. It’s easy to apply. It’s usually very much faster than putting on plates and screws. It’s used sometimes in contaminated fractures like the one I showed you with, the gentleman with the boney osteomyelitis. There’s many, many components out there. I don’t really personally say one is better than the other, what works best in your hands. But I can tell you that there are so many companies out there now that had many, many systems. Some have the pin-to-bar system that you have to actually take the pins to the bars. Some have rails. Some have rails that now have angulation to it or you have clamps and couplers. You have large bars, small bars, carbon bars. You have anything you want. It’s basically you build it. This is just a quick reference that I wanted to show you. There was 54 calcaneal fractures treated primarily with a mini ex-fix. The reason why I present this is because for years and years I’ve been taking about calcaneal fractures and the use of external fixation because that’s what I mainly do. Magnan had this article and he said, “Out of the 54 patients, 15 had standard type 2 fractures and 31 had standard type 3 fractures, and eight had type 4 fractures. In that, the results show that out of 49 of the 54, they had good to excellent results.” Now they use this score called the Maryland Foot score or the SAVE score which is the score out of Verona. That SAVE score was the score analysis of Verona which is actually used to determine the results via the CT scan and the functional results. So the CT scan, how it looked, and then the functional result of the patient. Out of those patients, two had fair results, three had pour results, and three had superficial pin infections. All the superficial pin infections were treated successfully with local wound care. Now although the study was very limited, it just shows that there is a good result. You can achieve a good result. The only question I have on good results, what is a good result in the calcaneal fracture? I mean really I don’t know because we always tell our patients this is the worst fracture you can get. But a good result where the patients are able to function, maybe we’re an orthotic, maybe walk without pain, maybe not have severe arthritic complications or infectious complications can be part of that good to excellent result. The limited study does show that this was actually very minimal complication compared to ORIF. Remember, in complications you have pin tract infections, loosening of the fixation. You can get sometimes the neuromuscular or the neurovascular areas can get impaled and you can get some neuritis or injury to the nerve. You can have the actual hardware fail or you can have breakage. Then the patients tend to be sometimes non-compliant. You put this on someone who has all their little wrenches at home and decide to place with the nuts and the bolts, that could change some of your results. I think it’s a good alternative to what we use. As I said, what I think is best about it is that you have a lot of ability to think out of the box, be very versatile.


    You can use it with or without internal fixation. Thank you.