Nicholas Bevilacqua, DPM discusses the indications, surgical techniques, and sample cases for the first metatarsophalangeal joint fusion. Dr Bevilacqua reviews specific surgical techniques including: incision placement, joint preparation, fusion position, and fixation construct.
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TAPE STARTS – [00:00]
Male Speaker: Our next speaker is Dr. Nicholas Bevilacqua. He’s – comes from Seaneck –Teaneck, New Jersey, here, hometown boy. A fellowship-trained surgeon, board certified in both foot and reconstructive rearfoot and ankle surgery by ABPS. And he is going to give us two presentations back-to-back. We’re going to do an arthrodesis, so the first MTP first, and then the ankle fusion surgical pros to optimize outcome.
So please give a warm welcome and your full attention. Thank you.
Nicholas Bevilacqua: All right, good afternoon. So I think we can conclude that podiatry is in good hands with these TV shows and hopefully – I think that’s a good sign that we have packed audience here.
So first metatarsophalangeal joint fusion, nothing disclose for this talk. And then, just some quick objectives. So we’re going to discuss the indications when we consider this procedure. And I’ll go into some of the components of the surgical technique, specifically incision placement, joint prep, you know, if there’s evidence guiding us between different ways to prepare the joint for fusion, the optimal position for fusion, and fixation constructs. You know, you walk out into the exhibit hall, you read articles, there’s plates, there’s screws, there’s locking plates and it can sometimes get a little bit confusing. And then, we’ll try to just tie it all together with some cases afterwards.
So why consider a fusion of the joint? So I think probably the best point is that it’s a very predictable procedure. So if you get a solid osseous fusion, toe is not going to deviate, you know, you’re not going to get any bunion reoccurrence or a reoccurrence of a hallux varus deformity. It has a very high patient satisfaction rate. So patients come in, let’s say, it’s hallux rigidus, they’re suffering for years and years with a painful joint.
So granted you’re fusing it, so you’re going to eliminate joint, but often times, you’re just eliminating just a few degrees of motion, but you’re going them pain relief and they’re very satisfied afterwards.
And I think importantly, it’s a definitive procedure.
So often times, you have patients present with, you know, this typical example. Here, I look at this kind of like a surgical misadventure. She’s had multiple procedures. You could see it was an attempt to the pan metatarsal head, maybe a Keller on that first. It’s unstable. She’s been through many surgeries. She comes to you, very reluctant to undergo another procedure because it’s just been, you know, failure after failure. But with a fusion, you have confidence that it’s going to be that sort of last procedure. It re-establishes the stability along the entire medial column of the foot and it re-establishes the weight-bearing pattern of the forefoot.
So probably one of the most common indications well-considered for is hallux rigidus. So we have these arthritic joints, pain with palpation, pain with range of motion. You open them up. It’s like a little bomb went off in there. There’s periarticuar spurring. This metatarsal head is shiny. There’s zero cartilage on it whatsoever.
And when we look at the grading system that, you know, you’re all familiar with, grade 1, grade 2, 3, 4. So 3 and 4, those are the ones where you’re going to, you know, most of the time think about, arthrodesis. What other options do we have? So usually, the milder case is grade 1, grade 2, kind of like to me, it works well, has been shown to have high satisfaction rate. And surprisingly, actually, a lower sort of reoperation rates, you know, it’s about 15% to 20%.
Osteotomy, if you think about this, you know, it’s called like a decompression osteotomy. Those you have to be a little bit careful. So Tom Roukis, he did a, you know, a great systematic review of first metatarsophalangeal joint fusions. And he found that patient satisfaction was about 70% after these periarticular osteotomies, and about 30% developed transmetatarsalgia or even stress fractures, and 22% require revision. So we have to use those types of procedures with caution.
So often times, kind of eliminated that. I’ll just go to a kind of like demand, sometimes, even consider an osteotomy in the phalanx like that Moberg osteotomy. And then, you can think about Kellers or interpositional arthroplasties. But I think out of all of these, the most definitive that hopefully one-and-done procedure is going to be an arthrodesis.
So other conditions, rheumatoid foot, I think, is probably the gold standard in a rheumatoid foot reconstruction. Whether you’re doing, you know, metatarsal head resections 2, 3, 4, and 5, you fuse that first metatarsophalangeal joint. You’re confident that you’re not going to get reoccurrence of deformity. You’re going to get a stable medial column.
Deformity correction, whether it’s severe hallux valgus, I mean, often times, you don’t think about fusion when it – for a bunion procedure, but it’s actually have been shown to work well for geriatric bunions or just really severe bunion deformities. And I’ll show – I’ll go over a study later that shows that just with fusion alone, you get significant reduction of that IM angle without having to do any other ancillary procedures.
Hallux varus, whether it’s congenital or iatrogrenic neuromuscular disease, again, it adds stability and then it’s just a great salver procedure whether it’s a failed bunionectomy that has a varus complication, or arthritis, a failed implant, failed Keller, or even in the metatarsal head. So when considering a first metatarsophalangeal joint fusion, obviously, you have to, you know, discuss the surgical goals and expectations with the patient because the first thing they hear is fusion and they sort of shy away. So they want motion in that big toe and, you know, in situations, that’s understandable so maybe not every patient is a candidate for it. But if they have, you know, severe grade 3 or 4 hallux rigidus and they have maybe five degrees of total range of motion and it’s pain and they’re compensating, you’re basically not eliminating much more motion and you’re going to alleviate their pain.
Contraindications basically, infection, peripheral arterial disease and I put here symptomatic, hallux IPJ, sort of, you know – oftentimes with the hallux rigidus, they’ll have some extra stress on that IPJ.
And radiographically, it may look bad but clinically, it’s asymptomatic. I mean, if they’re severely symptomatic, you may want to consider maintaining some motion in the metatarsophalangeal join and possibly even fusion at – fusing the IPJ.
Although there has been an article published and I’ve actually done it, you can see here, you do a fusion, years down the line they developed painful arthritic interphalangeal joint arthritis and you can actually fuse that joint. And if it’s in an optimal position, these patients do well.
So when we think about some of the pros with the surgical technique. So patient positioning, supine, cuff, tight tourniquet, whatever your preference is, plus or minus above or underneath the ipsilateral hip, you just want it basically the knee pointing straight up and then the heel at the edge of the table, just to help us assist with the floor.
So the incision oftentimes is going to be dorsal medial. I mean, you could do it medial, just got to make sure that you get, you know, as far lateral aspect to the joint. And then you also have to consider sometimes it’s a revision procedure, so you have to, you know, take into account their previous surgical scars.
So you want an incision that’s going to maximize exposure because you want to just – and we’ll go over to the importance of adequate preparation of the joints. We want to be able to remove the spurs, osteophytes, eliminate all the cartilage on the head and base, or the head of the metatarsal and base of the proximal phalanx. And typically, you’re going to dissect down, find EHL, keep it – try to keep it in the sheath, so this way, you know, if you are going to use hardware or a plate, you still have some coverage on that tendon there.
And then it’s usually straight incision right down to periosteum and bone, and then you’re just going to carefully deep dissection. And you want to be pretty aggressive releasing capsule in collateral ligaments, because you want to – you know, there’s a term sort of shotgun in the toe. Because you want to be able to really look at that base in the proximal phalanx, especially if you’re going to use any of these, you know, conical reamer systems.
Because you don’t want to, you know, have that first metatarsal head get in the way when you’re removing cartilage on the base of the proximal phalanx.
So joint prep. Any, you know – many options whether it’s hand instrumentation, osteotome and mallet, rongeur, power equipment, cup and cone reamers, burs, combination of the two, and really you want to remove all visible cartilage, but you also want to violate that that sort of calcified cartilage, that’s subchondral plate, subchondral drilling, fenestrating it, you know, fish scaling it or feathering it with osteotome and mallet. You want to, you know, think of it as, like, a controlled explosion. You really want to get down to healthy breathing bone.
And then what about technique, plantar resection versus conical reamer? Any evidence to tell us which one is better? Well there was actually a paper that looked specifically at the different techniques in terms of join preparation and outcomes of fusion. So this was a paper published and, you know, they were looking at changes in the length after these two approaches and they compared flat cut. So basically, plantar resection, metatarsal head, base of the phalanx, versus the conical reamer system. And they found, you know, 7 millimeters shortening with the flat cuts and 5.7 with conical reamers, no significant difference. So really, you know, changes in length as long as everything goes okay is not an issue.
So does it affect the outcome? There’s one technique better than the other. So it’s a different study and it looked at basically first metatarsophalangeal joint fusions comparing the different preparation techniques with the outcomes. There’s a large retrospective review, 200 fusions and about a 118 were plantar resection, 82, combination of either conical reaming, rongeur plus bur, or rongeur alone.
It basically just kept at ball and socket configuration of the joint. And vast majority of these were fixated with compression screws.
And they found – looking basically, their end point was radiographic evidence of fusion, sort of the union rates, pretty much identical, 92%, almost 93% for flat cut, 95% for ball and socket, so really no difference between the two techniques.
What was interesting is they did find a trend, a nano significant difference, but a trend towards poor or lower union rates when power instrumentation was used. So if the organ used power, you want to irrigate, you know, along the process, so you’re not causing necrosis. So their configuration was that – was that the technique for preparation did not statistically influence the outcome of the fusion.
So basically in summary, it’s really whatever you’re comfortable with. So when do we consider plantar resections? You know it’s straightforward, but optimal positioning can be challenging. This is where sort of the shortening, maybe an issue because you may make your cuts. If you don’t like it, you make another cut, you don’t like it, and you’re sort of chasing the deformity and quickly you get a lot of shortening.
So, you know, it’s useful in a tighter joint. You can just sort of, almost like an insight to a fusion, where you just cut or resect it in the position that’s in. And those patients do well.
Conical reamer, really the advantage is that you get that ball and socket joints so you can really dial in the correction. But again, people with poor bones, specifically rheumatoid foot, when you’re reaming the metatarsal head or even the base of the phalanx and if you put too much force, you can sort of go right through and then that will result in significant shortening.
So we just found out that the technique, whether it’s planar resection, conical reaming, no statistical difference between the two. What about fusion position?
So obviously I’m going to talk about different angles that you’re going to read about in articles, and textbooks, and hear at different lectures. And then we first have to think what measurement are they using, so you can measure these sort of intramedullary metatarsal compared to the phalanx or dorsal cortices as you can see. See if this will work here.
So dorsal cortices there. And that’s actually interesting because you can see how you have some dorsiflexed angle when you measure it intramedullary but the dorsal cortices is sort of parallel. So when you’re thinking about fixation later on, you know, straight plate, pre-bent plate, and you think, “I’ll have to dorsiflex at 15, 20 degrees, I’m going to use a 10 degree pre-contoured plate,” that’s going to really suck that proximal phalanx up and you’re going to get more than 25 degrees dorsiflexion. So you can actually use a straight plate and still achieve the desired dorsiflexion angle.
But before we get to the numbers, which we will, I think it’s just important that you match the needs of the patient and it should not be, sort of, cookbook where every patient gets 10 or 15 degrees valgus, 10 or 15 degrees dorsiflexion.
Oftentimes, these patients have lived with this condition for a long time and it’s just painful but it’s sort of in a functional position. So you don’t want to deviate too far away from that. And you’re going to see that we often – you know, just a subtle sort of malposition is going to really affect in a negative way their satisfaction with the procedure.
So when think about sagittal plane, just think dorsiflexion, you don’t want to planar flex it. So ideally, you’re going to do about 10 or 15 degrees relative to the sole of the foot and about 20 to 25 if you’re going to do that intramedullary measurement.
So intra-operatively, there’s many techniques described. You can use a flat surface or sometimes the cover of the screw caddy that you’re using and use that to simulate weight bearing. And you basically just want that proximal phalanx elevated.
Some papers even describe taking the handle of a screwdriver and sort of turning it, and that’s about the amount of elevation. But what you should do is once you sort of provisionally fixate it, you should be able to planar flex that IPJ and get toe purchase. So if you’re flexing it down and the tip of the hallux isn’t touching that board, that means it’s too dorsiflexed.
In a transverse plane, you want it to be in valgus, slight valgus, 10 or 15 degrees. If it’s in varus, they’re going to get issues on the medial aspect of the hallux, difficulty fitting in different types of shoes. And if you make it too far in valgus, they’re going to – it’s going to impinge on that second toe.
Frontal plane is simple. You just want that nail plate sticking straight up. You don’t want it rotated, prone or supinated position. So again, oftentimes when you get it right, you sort of don’t hear any complaints, the patients do well, but you know when you get it wrong because the patients are going to complain. If it’s too dorsiflexed, they’re going to have issues planarly on that sort of sesamoid overload, and most of the time they’re getting that sort of hammered hallux for compensation and they’re getting irritation in that dorsal IPJ. And they don’t like the way it looks also.
And you want to avoid excessive plantar flexion. So you need enough dorsiflexion, so at the end of mid-stance that their heel is lifting off the ground. If it’s too plantar flexed, they’re not going to be able to, and they’re going to get pain at the tip of the toe and it’s going to really accelerate IPJ degeneration. And you want to avoid in the transverse plane excessive varus, like we talked about, difficulty wearing shoes. And too far valgus, it’s going to impinge on that second toe. So oftentimes, on the transverse plane, I’ll kind of use the position of the second toe as my guide and I try to make it parallel to that second toe.
So fixation, this is where things get confusing. You can do perfect patient candidate, good joint prep, good position. How do we fixate this now? And again, there’s many options and this is the age of sort of, you know, our fixation with different fixations, different companies. They’re probably knocking at your door every week.
This is the latest and greatest best screw, best plate, locking plates, static plate, pre-contoured, so it can get confusing. So we have lots of options. So let’s see if there’s any evidence to sort of guide us in direction here.
So this was a – this was an interesting study. So this was published 2003, Politi and colleagues. So he looked at the biomechanical assessment of stability after first metatarsophalangeal joint fusion with five different constructs, five of the most common that we use. This is a synthetic bone model, so that’s important. It’s not – these aren’t patients walking on pressure analysis and they’re not looking at radiographic outcomes. This is synthetic bone model, just looking at which is the most stable and stiffest construct.
Lag screw dorsal plate, that was the most stable. So you can see here load to failure almost 5,000 Newton meters. Next in line, oblique lag screw then a dorsal plate alone, the weakest was that crossed K-wires.
So in this study using synthetic bone model, they found that lag screw plus a plate was the most stable and it was almost three times more stable than just using a lag screw alone. And a dorsal plate without screws was the weakest.
So if we think about the influence of fixation on stability, this is another – this is a cadaveric study. So the last one was synthetic bone model. This is cadaver, so nothing – again, it’s not clinical, but it just gives us an idea as to which construct, sort of living in a vacuum is the strongest. So they found load – this wasn’t load to failure. This was just how much load does it take to displace it up to 1 millimeter of displacement. Plain screw, 121 Newton meter of force, require cross screws 2, so it was significant difference. So we know that lag screw plus plate is differ – is more stable, but doesn’t really matter when we’re – we’re thinking about these, you know, outcomes of, you know, real life patients.
So this was an interesting study looking at the peak planner pressures under the hallux after the first metatarsophalangeal joint fusion. And using dynamic pressure analysis, they found that the peak pressure onto the hallux, after fusion for an average, you know, patient size, 70 kg person, was about 79 Newton centimeter square.
But now, you do the procedure, patients don’t walk there for – after the procedure. We’re going to put them in the protective device. It’s going to be either cam boot, surgical shoe. And this study looked at different devices, and how well they offload the forefoot, or how do they – how much pressure can they reduce. And you can see here the surgical shoe, the average sort of pressure on the hallux, when ambulating, was about 29 Newton cm per square.
So when we think about the data from the lab, and then the data in real life, you know, what can we summarize from this? So if we look at the amount of force to taste and displaces, 1 millimeter. Plain screws, strongest 121 cross screws, weaker at 72. We know that the peak pressure into the hallux for a 70 kg-person is about 79, so in theory, that maybe too much or cross screws, but again you’re not – these patients aren’t walking barefoot afterwards. They are in the surgical shoe and that’s where it reduces to 29%. So, you know, we think about which is the strongest, but does it really matter.
And Peter Bloom, he – his recent publication is primary one of the largest reviews for first metatarsophalangeal joint fusions. This is 262 fusion, all patients – so preparation was cup and cone reamers, so we did that ball and socket, and use 2 cross screws.
And he had a 96% fusion rate afterwards.
I think it’s important to note the post-op course, it did, you know, involved about 4 to 6 weeks of non-weight bearing, but you can still get good fusion with two cross screws, even though it’s not as stiff, not as stable as a plate and screws, so, you know, this could just be part of your thought process.
But what about, plates? So we know screws work, what about clinically had a place function? Is there a difference between leg, or locking plates, static plates, plus or minus compression screw. So Christopher Hyer and his colleagues out in Ohio, they looked at different plate constructs, so plate by itself, plate with screw in both static and locking. And these patients still – different from the last study because the last study was 4 to 6 six weeks non-weight bearing. This non-weight bearing for one week in the sort of ambulating in the boot. Overall fusion rate, 93%, and there was no difference between any of the constructs.
So with that knowledge, I think we should also take into account cost. I mean, obviously, there’s patient factor. There are some patients, heavy patients maybe, you know, co-morbid, maybe, you know, poor bone stock that are going to require a more rigid, more stable construct. But for the, run of the mill elective fusion, cost should play a little bit or a role, so again, Christopher Hyer and his group at Ohio separate study, they just did a cost comparison, dorsal plate with a screw, versus two cross screws.
Overall effusion rate, 91%. There was no difference between the two groups. Cost, I don’t think anyone surprises. See that there was a significant difference to the cross screws. Average cost was about $375, when he throws a plating into the mix, it jumps up to about $600, and you can see the range some of these, you know, up to $1,700. So no difference between time to fusion, revision surgery, or hardware removal, and fusion rates, but obviously, is a significant difference in cost.
Sometimes again, they are like, I just drew this up there. This lady, I had plan on just putting in two simple screws, poor bone stock. I wasn’t, you know, happy with the fixation and I ended up having the supplemented with a plate and even K-wires because I wasn’t getting a good bite with the compression screws. And thankfully, she went on to hill.
Post-op course, one of the biggest question and you see a lot of the studies, that’s where it’s – it’s hard to sort of compare outcomes, because joint preps different, fixation, kind of different between studies and also the post-op course. Some people say they let their patients ambulate, but when you look into the study, you know, they’re non-weight bearing for a week, maybe they’re in a cam boot or surgical shoes, so there’s a lot of variation.
So are we able to ambulate these patients immediately? Because I think, you know, that’s important when patients think about, you know, “Can I have this procedure?” Because I always tell patients, “Surgery is an easy part, as to recovery, that’s the tough part.” Surgery is 45 minutes, the recovery you know, non-weight bearing, that’s takes a toll in the patient in their family members.
So this, just looking at first metatarsophalangeal joint fusions where the screw in the locking plate, with immediate weight-bearing. Cup and cone reamers fixated with a dorsal plate and a leg screw, and they allowed from day zero walking in a post-op shoe. And fusion rate, 96%. Clinical healing was on average about six weeks and radiographic fusion almost seven weeks.
So I think using that data, if you are going to have these patients, you're going to put a strong, stable construct plate plus screw. You know, oftentimes I’ll give them crutches, surgical shoe. Crutches are sort of like as a form of pain management just because it might be too painful to put weight on it initially. And then I tell them they’re able to wean off crutches as tolerated. And I’ll keep them in that post-op shoe because we know that data reduces it to, like, that 29 Newton centimeter squared. I’ll keep them in that until I get, you know, clinical and radiographic signs of healing which, on average, is about six weeks or so.
So complications, most common complication that we’re going to see as a non-union, you read it in textbooks and journals and you’re taught that there’s a 10% non-union rate. Tom Roukis, he did, you know, a systematic review of I think it was about 37 studies, looked at almost 3,000 fusions and he found a non-union rate of 5.4%. What was interesting is that only about 2% were symptomatic. So I think we’re kind of like over-exaggerating the non-union rate.
Malunions, so this is something that theoretically should never happen, but there was about a 6% malunion rate. And again, any sort of error in positioning is going to influence the patient satisfaction. And then also a complication, you’re locking up that metatarsophalangeal joint, putting more stress proximal and distal, so you get IPJ arthritis. About a 30% incidence of radiographic changes but very few patients are actually symptomatic.
And then painful hardware. So, you know, that can also be with some of these. If it’s a bulky dorsal plate, that may require hardware removal. And in that Roukis review, about 8% of patients required hardware removal.
So what have we learned? I think, you know, it’s not specific joint prep or specific hardware. I think the success is multifactorial. I think it’s finding the right patient, having the right expectations. You want to adequately prepare the joint. Whether it’s cup and cone reamer, planar resection, it doesn’t matter. Just remove the cartilage, penetrate that subchondral plate. Positioning is key, so you want to place it in the optimal position that’s right for that particular patient. You want to employ stable fixation construct and the appropriate post-op course.
So I’ll just kind of conclude with just a couple of cases just to kind of highlight the utility of this procedure. So it can be used for severe bunions.
So you can see this patient, almost looks like a rheumatoid foot but it’s not, but severe bunion. Paul Dayton out of Des Moines, Iowa, he did studies looking specifically at the reduction of that intermetatarsal angle after a first metatarsophalangeal joint fusion. And it was a systematic review of 15 studies, about 700 fusions, and he found that pre-op, about a 14 degree IM angle, post-op it went down to about 9, so within that acceptable range. No other procedures were performed to reduce that intermetatarsal angle. It’s a powerful sort of bunion procedure as well.
Hallux varus, again I mentioned that before, whether it’s congenital hallux varus, if there’s a neuromuscular condition or if it’s a complication from a bunion surgery, it’s a very good definitive procedure. So hallux varus correction after bunion surgery can go in there, soft tissue rebalancing. And even that, sometimes there’s a high recurrence rate or the joint is stiff, the joint’s painful and patients are unhappy. You fuse it. Once you get that joint fused, pain goes away and it’s functional. And these are just different examples.
Rheumatoid arthritis I think is the gold standard. Fusing that first metatarsophalangeal joint and whether you’re going to do, you know, metatarsal head resections. I tend to do metatarsal head resections as opposed to, you know, Weil osteotomies, only because these are lower demand patients, they just want pain relief. They’re not highly active, so you’re offloading that plantar forefoot. So you combine that with that fusion and patients do very well.
And I think for failed implant as a salvage procedure, it restores stability, whether it’s the silastic implant. Oftentimes you have to remove the implant, debride, you’re left with a defect, bone graft fusion.
And in these cases, it works well. You can see this patient, again, this was kind of a surgical misadventure. He had a bunion complicated by infection, had an attempt at a fusion, by the time I saw him, you know, thankfully the infection was resolved but he required bone graft fusion. And they’re just happy because, again, it just restores stability in their foot.
This was the example I showed earlier. And it’s powerful revision procedure. Just because going back to that first slide, it’s definitive. You know, especially when patients have had – this patient you can see here, she had just soft tissue bump and run on that big toe, she had soft tissue procedures at the metatarsophalangeal joints, had fusions, but she had dislocated lesser MTPJs. And it worked well, fused the joint. In this case, I ended up doing a pan metatarsal head resection.
All right, so that’s it for first MTPJ infusion.
TAPE ENDS - [29:05]