Meet the 2025 Leonard Goldner Award Winner: Metabolic Activity at the Bone-Implant Interface Following Total Ankle Replacement: A Two-Year Cross-Sectional Study of Asymptomatic Patients Evaluated With 18F-NaF Positron Emission Tomography

Summary

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Podcast Summary: Meet the 2025 Leonard Goldner Award Winner

Podcast: The AOFAS Orthopod-Cast
Host: Ben Jackson (AOFAS Podcast Committee)
Guests: Dr. Liz Cody and Dr. Constantine Demetrikopoulos
Episode Date: November 26, 2025

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Overview:

This episode features Dr. Liz Cody and Dr. Constantine Demetrikopoulos, recipients of the Leonard Goldner Award, discussing their award-winning study, “Metabolic Activity at the Bone-Implant Interface Following Total Ankle Replacement: A Two-Year Cross-Sectional Study of Asymptomatic Patients Evaluated With 18F-NaF Positron Emission Tomography.” The discussion revolves around what constitutes "normal" metabolic activity at bone-implant interfaces after total ankle replacement, explored with advanced imaging, and how clinicians can better interpret scans in patients without symptoms.

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Key Discussion Points & Insights

1. The Study’s Motivation and Research Question

• Defining "Normal":
  There is a current gap in the understanding of what post-operative imaging should look like in asymptomatic (problem-free) patients after total ankle replacement. Most imaging is performed when there is pain, possibly prompting unnecessary revisions.
• Study Objective:
  Determine baseline metabolic activity in the bone surrounding ankle implants using PET scans, to differentiate between normal post-surgical activity and pathology.

  “We wanted to know what metabolic activity around ankle replacements is like in the short period… after surgery. And we wanted to know when that activity...normalizes so we have something to go off of...”
  —Dr. Liz Cody, [00:59]

2. Study Design and Patient Groups

• Patient Cohorts & Imaging Intervals:
  The cohort consisted of eight different asymptomatic patients per time point, imaged at 6, 12, 18, and 24 months after surgery.
• Longitudinal Tracking Limitation:
  Patients were not followed longitudinally through all intervals; rather, each interval had different patients.

3. Why PET over SPECT?

• Technical Differences:
  PET (Positron Emission Tomography) offers improved spatial resolution and dynamic imaging capabilities compared to SPECT (Single Photon Emission Computed Tomography).

  “With PET...you get better spatial resolution...and you can do a dynamic PET scan, so you can actually see the dynamic movement of the tracer...”
  —Dr. Liz Cody, [02:30]

• Current Clinical Practice:
  SPECT is still more commonly used and typically approved by insurance, but PET may become more prevalent as evidence builds.

4. Main Findings and Clinical Implications

• Results Overview:

  • Metabolic activity around the implant remains persistently elevated during the first two years post-op, even in asymptomatic patients.
  • Activity generally increased between 6 and 12 months, then gradually decreased.
  • The talus showed higher uptake than the tibia.

  “We found that activity did remain elevated throughout that two year period...activity increased in the first year...and then it started going down after 12 months...the talus pretty much consistently had higher uptake than the tibia…”
  —Dr. Liz Cody, [04:31]

• Clinical Takeaway:
  Be cautious interpreting bone scan imaging within the first two years after surgery since elevated activity may be normal—even in patients doing well.

  “If you're doing one of these scans within two years of surgery, you just want to really interpret it with a lot of caution.”
  —Dr. Liz Cody, [08:22]

5. Broader Application, Funding, and Future Research

• Funding Challenges:
  Imaging studies can be expensive ($5,000 per scan cited as an example), making large-scale research difficult without institutional or association support.

  “It's really tough to get funding because who's going to pay for this?...I think the AOFAS does a really tremendous job offering funding for these types of research studies.”
  —Dr. Constantine Demetrikopoulos, [07:36]

• Support Opportunities:
  The AOFAS offers several grant mechanisms for funding foot and ankle research.

• Next Steps:

  • Longitudinal patient tracking (same patients over time)
  • Expanding to symptomatic patients and comparing to imaging findings
  • Potential for prospective studies to refine diagnostic criteria for painful ankle replacements

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Notable Quotes & Memorable Moments

• On Imaging Confusion:

  “A lot of times you see a lot of activity around the implant. You think, oh, it’s loose. And then people undergo revision surgeries for that. But…the truth is we don’t know what [scans] look like in asymptomatic people.”
  —Dr. Liz Cody, [00:59]

• On Technology Differentiation:

  “SPECT scan is single photon emission computed tomography and PET scan is positron emission tomography...you get better spatial resolution with PET…”
  —Dr. Liz Cody, [02:21 & 02:30]

• On Results and Clinical Application:

  “I think you just want to really interpret it with a lot of caution. And, you know, you're probably going to get more valuable information if you are doing it farther out from surgery, like more than two years out.”
  —Dr. Liz Cody, [08:22]

• On Clinical Frustrations:

  “In my clinical practice...I think the biggest thing I see is gutter impingement...trying to figure that out...”
  —Ben Jackson, [06:25]

• On Practical Guidance for Radiology Reports:

  “So really we should say clinical correlation recommended is that we should say after this.”
  —Ben Jackson, [08:34]

• On Funding Reality:

  “You can do a $50,000 study, a $25,000 study, but even a $10,000 study...the AOFAS does a really tremendous job offering funding for these types of research studies.”
  —Dr. Constantine Demetrikopoulos, [07:36]

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Important Segment Timestamps

• [00:59] — Study aim: defining normal metabolic activity in ankle replacements
• [02:21–03:02] — SPECT vs. PET: Why PET was chosen
• [04:31] — Main findings: persistent metabolic activity, differences between tibia and talus
• [05:05 & 05:21] — Limitations and future research directions
• [07:36] — Funding practicalities and AOFAS research opportunities
• [08:22–08:34] — Clinical application: “interpret with caution,” importance of timing in imaging

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Final Takeaways

• Elevated metabolic activity on bone scans within two years of total ankle replacement may be normal, even in pain-free patients.
• Clinicians should interpret such imaging cautiously in postoperative patients and consider waiting longer before acting on apparent abnormalities.
• Continued research is needed to refine diagnostic criteria for failed ankle replacements, with future studies ideally including longitudinal tracking and symptomatic cases.
• Funding opportunities exist, particularly through specialty societies like AOFAS.

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For more information, visit aofas.org or tune in to future Orthopod-Cast episodes for further research highlights in foot and ankle orthopaedics.

Transcript

[A]

Welcome to AOFAS Ortho podcast, where leaders in foot and ankle orthopedic surgery discuss the issues that affect you and your practice. Please note that the views expressed on this podcast do not necessarily represent the views of the AOFAS or its members.

[B]

Hey, this is Ben Jackson here at the annual meeting and we're doing another AOFAS podcast. We're fortunately here and I'm joined by Dr. Cody and Dr. Demetrikopoulos, who've won the Leonard Goldner award. So first of all, congratulations on that amazing award. That's awesome. So their incredibly long title to a very detailed outstanding study. I'm going to summarize it and not read every word, but basically they're looking at metabolic bone activity after total ankle replacement and they did a two year study using PET scan. So first of all, tell me what was the question you were trying to answer with this particular study?

[C]

So, you know, we've noticed that people are increasingly using spec CTs to look at activity around ankle replacements to try to diagnose what's causing a painful total ankle replacement. And a lot of times you see a lot of activity around the implant. You think, oh, it's loose. And then people undergo revision surgeries for that. But, you know, a lot of information is taken away from these scans. But the truth is we don't know what they look like in asymptomatic people. Like, what are the people who are doing well, what are their specialists scans look like? So we just have no record of what it should look like in asymptomatic patients. So we wanted to know what metabolic activity around ankle replacements is like in the short period, you know, the first few years after surgery. And we wanted to know when that activity around the implant after surgery kind of normalizes so that we have something to go off of when we're interpreting these studies in patients who are actually having problems.

[B]

This is a question we come across. I come across all the time, my patients like, what is normal? So you're really trying to establish what is normal in these patients by just sort of scanning everyone. So what interval did you do the scan after surgery?

[C]

Yeah, so we got eight patients at each of four time intervals. So six months, 12 months, 18 months and two years.

[B]

Outstanding. And so we talked about this a little bit offline before we started. But so as you mentioned, a lot of people are doing spec scans. That's what I'm doing is a spec scan. Why did you select PET scans? And for a dumb guy from South Carolina, what is the difference between a PET scan and a SPEC scan.

[C]

So SPECT scan is single photon emission computed tomography and PET scan is positron emission tomography.

[B]

So those are big words. You're so smart, that's why you might want to worry.

[C]

I really can't go beyond just describing what they are, but basically we chose PET because you get better spatial resolution with pet and you can do a dynamic PET scan, so you can actually see the dynamic movement of the tracer over the time of the scan. So over the 45 minutes that the tracer is being infused and circulating, you can actually see what's happening with it. So the ability to both have better resolution of the images and seeing where the trace is accumulating, together with the fact that you can use these dynamic measures to get a better idea of what's going on, it just enabled us to do more.

[B]

And this may be outside the scope of beer study. Do you have any sense which one costs more?

[C]

Well, I think SPECT is the one that typically gets approved by insurance, but the feeling is that just that, you know, PET is better, so probably eventually may move towards pet, but they accomplish similar things because both are targeting bone and kind of the bone turnover phase. So you're really looking at the same thing with both scans.

[D]

And to add to Liz's point, you know, when we first started looking at these questions, we utilized PET CT because we could look at the vascularity of bone around ankle replacement. And so the first study that we did was asking the question, what happens to the blood flow around the talus after an ankle replacement? And we specifically looked at the six month time point and PETCT allowed us to ask that question. And we really leveraged our relationship with Weill, Cornell and Jonathan dyke, who's a PhD on the project, who's really published a lot, both in ankles with our department, but also in other joints. Using that technology and those studies, Liz asked the question, well, again, what happens in asymptomatic patients that are doing very well? So all of the patients in the study were happy, didn't have any pain, followed the normal course of an ankle replacement. And we saw that in those patients there was still persistent activity and that activity dissipated differently for the tibia and the tailus.

[B]

Yeah. So we're in suspense now. I've been asking crazy questions about what the difference in a SPECT scan and a PET scan is. So what were your results? So tell us all about it and what we should take away from this project.

[C]

Yeah, well, it was really interesting. So we found that Activity did remain elevated throughout that two year period that we were looking at people, but generally activity increased in the first year. So between six and 12 months, activity around both the tibia and the tail has actually increased a little bit. And then it started going down after 12 months. And as Constantine mentioned, the talus pretty much consistently had higher uptake than the tibia, which was interesting.

[B]

Yep, fascinating. So. So what would you say the next steps are in this line of research? Or are there next steps? Or do you feel like you've answered the question? But did this lead to more questions?

[C]

Yeah, I mean, you know, we only had eight patients in each group and they were all different patients. We weren't able to follow people longitudinally. So I think it'd be interesting to follow individual patients longitudinally. I think it'd be interesting to look at more numbers of patients, may maybe longer term follow up. We could start looking at patients who actually have pathology.

[D]

You know, we've previously done research looking at painful ankle replacements that go to the operating room. And we did a study utilizing the more conventional spec ct, which is still what we use clinically. So so far PET CT at our institution is still a research tool clinically for our patients. We still utilize a traditional spec ct, again, as Liz pointed out, with slightly lesser spatial resolution, knowing exactly where that activity is between the implant and the bone. And so we've previously done research in painful ankle replacements retrospectively and asking the question, those who went to the operating room to address their pain, what were the spec CT findings, what were the MRI findings and what were the intraoperative findings? And then correlating to see, okay, what is more accurate? Maybe in certain instances an MRI may be more accurate than a spec ct. Now the next step is we need to do the study prospectively and really look at all painful ankle replacements that return to the or have complete imaging and really be able to provide better guidelines for how clinicians can really diagnose a painful ankle replacement.

[B]

Yeah, I agree, it's a difficult question. In my clinical practice, I think the biggest thing I see is gutter impingement. And that's where I think the SPECT is helpful. I really don't see loosening all that often. It's actually pretty rare in the patients that I take care of. Of course, it's not never we all have a loose total ankle, but it seems to be a lot more gutter impingement. And trying to figure that out, and I try to like the dickens to prevent it. But then the question is, so if, if Somebody's lighting up one year later in their medial or lateral gutter. Should I just wait longer? Right. And so it sounds like maybe I should. It's still hard to say yet, but I think your line of questioning is really great. So as a research guy, I've got a question. So I find this an incredibly practical question that you guys tried to ask. I think it's really tough to get funding because who's going to pay for this? I don't think the NIH is paying for this. I mean, maybe this is an AOFS grant, but when these scans, I'm going to make up a number of calls. $5,000 a piece. You don't get that many scans in order to do this. And expect CT scan and MRI scan or find some patient you can Track and get 10 of them. I mean, 10 people with a $5,000 scan. You just spent entire hundred dollars. Actually, 1300. Okay, that's actually not as bad. But I mean, it becomes difficult. So how do you guys approach the funding part of this when this is not. Maybe some industry would have a huge interest in. Because you're talking about revising their total angles potentially. So how do you think about that?

[D]

You know, the AFAS has tremendous funding opportunities for their members to do research. You know, every year I'm on the research committee and we review grant applications and there's various levels. So you can do a $50,000 study, a $25,000 study, but even a $10,000 study. So there is money that is provided through the AOFAS for this type of research. And I would encourage those that are interested to really pursue those opportunities and apply. In this instance. We were fortunate Liz applied for an internal institutional grant, and so we were able to use those funds for the study. And certainly that may not be available to everyone, but I think the AOFAS does a really tremendous job offering funding for these types of research studies.

[B]

Yeah, that's a great plug and a great point. So any other final takeaways that we should get from this project?

[C]

I think just if you're doing one of these scans within two years of surgery, I think you just want to really interpret it with a lot of caution. And, you know, you're probably going to get more valuable information if you are doing it farther out from surgery, like more than two years out.

[B]

So really we should say clinical correlation recommended is that we should say after this.

[C]

Perfectly.

[B]

That is our takeaway. We should have that radiology read at the end of it. Well, I would say I appreciate you guys doing this work as a person that has this problem in my clinical practice. So I really appreciate you guys taking the time to do this work and thanks for sharing it with us. And really congratulations on an award well earned. So congrats guys.

[A]

Thank you, thank you, thank you for listening to the AOFAS Ortho Podcast, a Convey Med production. To learn more about joining our dynamic community of highly skilled orthopedic specialists, visit aofas.org.