FAI August 2024 Podcast: Changes in Foot Width in Minimally Invasive Bunionectomy

Summary

Summary: Foot & Ankle International Podcast — "Changes in Foot Width in Minimally Invasive Bunionectomy"

Release Date: August 27, 2024
Guests: Dr. Charlie Saltzman (Host/Editor, FAI), Dr. Holly Johnson (Senior Author, HSS NYC)

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Episode Overview

This episode features a discussion between FAI Editor Dr. Charlie Saltzman and Dr. Holly Johnson, foot and ankle surgeon at Hospital for Special Surgery, New York. The focus is Dr. Johnson's lead paper detailing post-surgical changes in foot width in patients undergoing minimally invasive (MIS) distal Chevron Akin bunionectomy. The conversation explores study findings, clinical implications, patient selection, and evolving best practices.

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Key Discussion Points & Insights

1. Study Summary and Rationale

• Dr. Johnson shares her clinical experience:
  • Over 800-900 MIS distal Chevron procedures performed since 2017
  • Noted a subset of patients with midfoot widening after surgery
• Methodology:
  • Retrospective review of patients with good pre- and postoperative radiographs (X-rays, some CT scans)
  • Measured foot width at the medial eminence and mid-shaft before surgery and at 6 months postoperatively
• Findings:
  • Average narrowing at the medial eminence (expected after bunionectomy)
  • Subset of patients (avg. +4mm) developed midfoot widening at the shaft, often at the location of the distal screw
  • Most patients not clinically bothered; a small proportion (5–8%) needed additional surgery for discomfort

"What we found on average was that we were able to narrow the width of the foot at the medial eminence, which is what one would expect after bunion surgery. But we also had a subset of patients that were wider at the midfoot area, approximately. This averaged about 4 millimeters."
— Dr. Holly Johnson (02:58)

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2. Clinical Relevance and Patient Complaints

• Nature of patient complaints:
  • Discomfort and difficulty fitting into fashion or formal shoes due to midfoot prominence
  • Not typically an issue for sneakers/athletic footwear
• Interventions:
  • Secondary procedure (remove distal screw, shave bone) yields high satisfaction in affected patients
  • Noted that screw placement/submersion unlikely to be the sole cause—the bone itself is prominent

"There’s a subset of patients that come in after all the swelling’s down, and the foot generally looks very good, but they point to the area on the foot...where they feel a bump or prominence."
— Dr. Holly Johnson (05:27)

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3. Mechanism: Why Does This Occur?

• Role of the first TMT joint:
  • Procedure aims to 'lock' the first tarsometatarsal (TMT) joint by shifting the metatarsal shaft medially and head laterally
  • Instability or slippage at TMT joint may result in persistent or increased midfoot width
  • Possible contributions from ligamentous laxity or inter-cuneiform instability

"Despite doing that intraoperatively, over time, whether the ligaments stretch out or whether there’s something else going on, the joint’s not locked. And these are the patients where we’re seeing this widening of the midfoot."
— Dr. Holly Johnson (08:08)

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4. Broader Context: Is This Unique to MIS?

• Possible occurrence in other bunion surgeries:
  • Similar midfoot widening/slippage seen in older proximal osteotomy techniques
  • High recurrence rates previously documented in literature (Scott Ellis et al.)
  • Instability can arise if there’s gapping between medial/middle cuneiforms

"I think we see it in the proximal osteotomies...patients sort of slipped out at the first tarsometatarsal joint."
— Dr. Holly Johnson (09:48)

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5. Evolving Practice & Patient Selection

• Current clinical algorithm:
  • Careful assessment of hypermobility at first TMT, including subjective exam and radiographic evaluation
  • Plantar gapping on lateral X-rays and medial slippage on AP X-rays are red flags
  • Distal correction (MIS) with counseling: 5–8% risk of secondary procedure, <1% risk of symptomatic recurrence needing revision (Lapidus)
  • Lapidus fusion preferred if instability/hypermobility is detected preoperatively
• Shared decision-making:
  • Patients informed about small but real possibility of further procedures
  • Revision (Lapidus) remains rare and reserved for persistent symptomatic recurrence

"Every single patient I do an MIS or distal correction on, I say there's a 5 to 8% chance we go back...I also counsel patients as well there’s a less than 1% risk that you have enough of a recurrence that you may want to have another surgery."
— Dr. Holly Johnson (12:39)

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6. Looking Forward: Future Directions & Research

• Avoiding dogma in bunion correction:
  • Importance of individualized care and comprehensive preoperative evaluation
  • Both distal corrections and Lapidus have a role; selection should be tailored
• Emerging tools:
  • Ongoing research using CT to evaluate TMT morphology for better personalized treatment
  • Goal: Predict and preemptively select ideal procedure for each patient

"I think there’s a lot of dogma around one Bunyan correction being correct or another one being better...I think it’s going to be a mixture of the two. We just—I’m really trying to narrow that algorithm down."
— Dr. Holly Johnson (15:30)

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Notable Quotes (with Timestamps)

• On study impact:

  "These are short reports...they become fully referenced in PubMed and are fully downloadable and searchable and can have a lot of impact as I believe this paper will."
  — Dr. Charlie Saltzman (00:29)

• On secondary intervention:

  "It does require a second surgery to go back in, take out the distal screw, shave down the bone to...narrow the foot. And, then it really does solve the problem."
  — Dr. Holly Johnson (06:37)

• On emerging algorithms:

  "We have some exciting CAT scan data...and we’re trying to use that morphology to help guide which procedure will be better for which patient."
  — Dr. Holly Johnson (16:18)

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Important Segment Timestamps

• Study Summary & Findings: 01:58–05:11
• Mechanism & Clinical Experience: 05:11–09:34
• Broader Surgical Context: 09:34–11:01
• Patient Selection & Counseling: 11:01–14:40
• Practice Philosophy & Future Research: 15:29–17:14

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Conclusion

Dr. Johnson’s study and discussion offer valuable updates on the nuances of foot width changes after MIS bunion surgery. While most patients benefit from a narrower foot, a small subset develop symptomatic midfoot widening, likely due to underlying joint instability rather than hardware prominence. Proactive assessment and patient counseling are key, and ongoing research promises to further refine individualized treatment algorithms.

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For more in-depth discussion and future research updates, stay tuned to Foot & Ankle International and upcoming publications from Dr. Johnson’s group.

Transcript

[A]

This is Charlie Saltzman, Editor of Foot and Ankle International. Today I have the distinct honor of talking with Dr. Holly Johnson who is the senior author of August's lead paper in Foot and Ankle International. Paper is titled Changes in Foot Width in Minimally Invasive Bunionectomy. This is a short report and for all listeners I want you to know this is a great way to get novel findings out to our readership and follow up studies of previously reported sets, data sets or trials. As they are short, they should be easier to prepare. When published, they become fully referenced in PubMed and are fully downloadable and searchable and can have a lot of impact as I believe this paper will Dr. Holly Johnson is a foot and Ankle Surgeon at the Hospital for Special Surgery in New York City City. She has served in many roles for the Foot and Ankle Society including is a Specialty Content Editor of Foot and Ankle International and Foot and Ankle Orthopedics. She has been instrumental to the mission of the American Orthopedic Foot and Ankle Society and has served on the Board of Directors as a member at large on the Orthopedic Foot and Ankle Foundation Board of Directors. Also as a member at large, she served on the Humanitarian Committee, the Program Committee, the DEI Committee, and co founded the Women's Task Force. In her job in New York City, she's the team physician for the WNBA's New York Liberty and the NHL's New York Rangers. She's an outstanding surgeon and an outstanding ambassador for our field of medicine. Welcome to the program, Holly. I'd like to start by asking if you can give a brief summary of your paper and its major findings.

[B]

Sure. And Charlie, thanks for the introduction and it's an honor to be interviewed for this podcast. So, as many may know or may not know, I've really embraced minimally invasive hallux valgus correction since 2017 and have probably performed somewhere between 800 and 900 of these distal Chevron Aiken procedures. As I've been doing the procedure and following up my results, I've been trying to figure out who the best patients are for this procedure, who benefits the most and who are the patients that we want to avoid. Looking back at all my data, what I found that there's a subset of patients who whose feet seem to be wider in the midfoot area after the procedure and originally I thought this might have been because of the distal screw and maybe patients were having pain from the screw and that made their foot wider. But as I began to examine this more, what I found was that really it was the bone Itself that that was causing the foot to be wider. So the study itself went back and looked at a subset of patients where we had good radiologic data on both pre op and post op X rays. We also have CT scans on this patient, but this was on these patients, but this was really an X ray study. And we measured the width of their foot both at the medial eminence as well as more in the mid shaft, and measured them before surgery and approximately six months after surgery when the osteotomies were healed. All of these patients had hallux valgus deformities. They had a surgery with a distal chevron and aiken. And then afterwards we measured the width of their foot. And what we found on average was that we were able to narrow the width of the foot at the medial eminence, which is what one would expect after bunion surgery. But we also had a subset of patients that were wider at the midfoot area, approximately. This averaged about 4 millimeters. Now, it wasn't all patients. Some patients were narrowed and some patients had a foot width in the midfoot area of greater than 4 millimeters. The average was about 4. And where originally I thought maybe this was due to the distal screw, because where we measured the foot width was at the distal screw location where the head was. But really what I think it is is that we put the metatarsal shaft and so much adduction as we shift the head laterally that we end up widening the foot in some cases. Now, this isn't necessarily clinically relevant. A lot of these patients are. Most of the patients are extremely happy with the results and they don't mention the foot width at all. However, in about 5 to 8% of my patients, I'm going back and I'm removing the distal screw and I'm shaving down some bone. And I think that's because the foot width itself bothers some patients in shoes.

[A]

That's fascinating, and I guess I understand why you wanted to study this. I suppose some patients came in and said, this is bothering me in this location. Is that how you stumbled on it or.

[B]

Sure. So what would happen is there's a subset of patients that come in after all the swellings down, and the foot generally looks very good, but they point to the area on the foot and again, it's in the region of the distal screw head where they feel a bump or prominence. Or they tell me that they can't wear, you know, narrow, their foot's more narrow, but they can't wear their shoes. And it causes a Lot of discomfort. Now these are generally patients who are not trying to get into a sneaker, but trying to get into more of a higher fashion shoe, a work shoe, a loafer or a heel. And they find that the shoe rubs on the mid shaft region of the first metatarsal. And you can often feel this prominence and again, it's in the region of the distal screw. So I thought originally, well, wow, maybe I'm not, I'm not recessing that distal screw enough. But every time I put the distal screw in, I sink it below the cortex, actually. And so when we started to really look at this primarily with CAT scan, what I found was it wasn't so much that it was the screw itself, but it was at the edge of the, it was really the edge of the bone. And when I remove the distal screw and I shave down that area of the bone to essentially narrow the foot, these patients were quite happy. Now this is again, I wanna be very clear, in the study, it was 5%, I would say generally, anecdotally, it's probably more like 5 to 8% of patients. So it's a small percentage of patients. But it does require a second surgery to go back in, take out the distal screw, shave down the bone to, and then it really does solve the problem. But I think it would be nice to be able to predict to this what will happen to. And wondering if there's some consequences long term to this.

[A]

Why do you think it happens in some patients and not in others? Is it mostly the shoes they want to wear or is it there's something else going on?

[B]

I think it's the mobility at the TMT joint. So when we do this procedure, and I learned how to do this from Joelle Vernois and David Redfern, who are the ones who first described it. And there have been a few papers written on this, both by Joelle as well as Peter Lamb from Australia. You make the cut, and whether you do a flat horizontal cut or you're doing a chevron, the goal is not so much to shift the head laterally, but to really shift the shaft medially and to lock in that TMT joint. So you're trying to shift the head and medialize the shaft in order to take the ligaments of the TMT joint to their maximum stretch. And the concept is that you're locking that TMT so that when the patient weight bears, there's no recurrence, there's no movement at the TMT joint. And so every time I do this procedure, I'm aiming to lock that TMT joint. What I found is despite doing that intraoperatively over time, whether the ligaments stretch out or whether there's something else going on, the joint's not locked. And these are the patients where we're seeing this widening of the midfoot and, and I think some of it is because the first TMT joint slips, and this is how I describe it, where the first metatarsal slips off of the medial cuneiform as those. Again, I'm not sure if it's whether the ligaments stretch out or maybe I feel like I've locked in that TMT joint during surgery, but in fact it's not. Or there are other things at play. But these are the patients who demonstrate the highest level of foot width when they have that slippage at the first TMT joint.

[A]

Do you think it's possibly common in other types of bunion surgery and we simply have not recognized it, or do you think it's more unique to the MIS techniques?

[B]

No, I think that we see it. I think we see it in the proximal osteotomies. So there was those proximal opening wedge osteotomies that were popular maybe in the 10, 15 years ago. And actually one of my partners, Scott Ellis, wrote a nice paper showing the high recurrence rate of this procedure, and that was published in FAI, I want to say 10 or 12 years ago or something, but basically showed a high recurrence rate. And I think that's because these patients sort of slipped out at the first tarso metatarsal joint. I haven't looked back at his X rays, but that's where I suspect those recurrences came from. I also think there's inner cuneiform instability that also adds to this. And so you may lock in the first TMT joint, but if there's gapping between the first and second or the, sorry, the middle and medial cuneiforms, you're also going to get that, that widening of that midfoot area as the patient weight bears and sort of splays through the midfoot.

[A]

So as you now approach your practice and you talk to patients and you examine them and you're trying to sort out what to do for a patient with a bunion deformity. Is there anything now that you would do differently in terms of determining who is eligible for this type of approach? You're the MIS approach, I should say, versus alternative, say lapidus type fusion.

[B]

I really try to identify patients who have hypermobility. And when I say hypermobility I mean they have ligamentous laxity at the first terse of anatarsal joint or at the inner, the inner cuneiform area between the medial and the middle cuneiform. And so when I'm examining a patient it's a completely subjective test, I admit, but I try to immobilize the midfoot and I move the first metatarsal up and down to try to identify these patients subjectively. And in addition, objectively we have X rays and on the X rays if they have plantar gapping immediately I know that's on the lateral view, plantar gapping or first TMT joint, then they're at high risk for this, this TMT slippage postoperatively. And on the AP view. There are some patients who even on their AP weight bearing X ray you can see the first metatarsal slipping medially off of the medial cuneiform by 1 or 2 millimeters even. And for those patients they would immediately, I would do a lapidus on them. However, there's a subset of patients where you don't identify that pre operatively and this constitutes those patients who, and about 5 to 8% of them, I'm going back and I'm taking out the hardware and shaving down the bone. Now I counsel patients ahead of time that you know, you, every single patient I do an mis or distal correction on, I say there's a 5 to 8% chance. We go back. I tell them about the surgery. It truly is a three day recovery, the surgery to remove the screw, it takes about a half, half an hour. Patients can weight bear immediately and they're back in their shoes in three days. So most patients are completely acceptable of that risk and of the consequences of having to have another surgery. But I do counsel all those patients ahead of time. Now even within that population of patients that we take back, more troublesome is the smaller risk of recurrence. So there's also a subset of patients, and this constitutes less than 1% of my patients who have this procedure who have a recurrence and that recurrence happens because of the TMT slippage. And those patients are much more challenging to treat because I think that the only bailout in that case if they have a symptomatic recurrence is a lapidus. And again thankfully it's a very small percentage of patients. We've gone back and looked at all of my bunions and I, it's about, it's less than 1% and I think I've, I think I've only revised one or two of them because most patients, even though we see that big slippage on the X ray, they're not symptomatic enough to warrant a revision. But I also counsel patients as well. There's a less than 1% risk that you have enough of a recurrence that you may want to have another surgery.

[A]

Well, it sounds like you've got the algorithm sorted out very well for your. Your clinical practice and have given us a good idea how to handle these patients if they come back with a problem. And by removing the distal screw, removing a little bit of bone and letting them get on with life, which seems totally reasonable, it's relatively small. Nothing is small in surgery, and anything can cause a complication. So I appreciate you bringing this observation to all of us. Wondered if there's anything else you'd like to add that would complement this observation at this point in time or in terms of how your practice is evolving?

[B]

Yeah, I think that there's a lot of dogma around one Bunyan correction being correct or another one being better. And I think that, you know, just like in so many of the other procedures we do in the foot, you really have to evaluate the entire foot when you're thinking about even which bunion correction to do. So for me, I do a lot of lapiduses and I do a lot of distal corrections. And I suspect that as more and more people are. Are embracing the concepts behind hypermobility and really trying to identify, you know, which patients we should be doing which procedure on, I think that what we're going to find is that there will be an algorithm and there's room for all sorts of bunion procedures to help a patient. And I don't think that one is going to be right or the other is going to be right. I think it's going to be a mixture of the two. We just. I'm really trying to narrow that algorithm down. The other thing is, is we have some exciting CAT scan data that's coming out where we've looked at the morphology of the first TMT joint, and we're trying to use that morphology to help guide which procedure will be better for which patient. And I think if we can. If we can nail that down, we'll be able to identify the patients who are at higher risk of recurrence with the distal correction, and then, you know, preemptively identify the patients who most likely are going to need a lapidus ahead of time. So we have some exciting stuff coming out.

[A]

Well, we look forward to seeing that, and hopefully you'll consider sending it into Foot and Ankle International for consideration. I want to thank you, Dr. Johnson. I'm Charlie Saltzman, editor of Foot and Ankle International. Today. I've had the distinct pleasure of talking with Dr. Holly Johnson from Hospital Special Surgery in New York City, who is the senior authority and the surgeon for these cases that were presented in her paper, which is a lead paper in the Foot and Ankle International this month, entitled Changes in Foot Width in Minimally Invasive bunionectomy. Thank you, Dr. Johnson, for being with us today.