Podcast Summary: FAI December 2025 Podcast

Title: "Impact of Prior Ipsilateral Arthrodesis on Subsequent Ankle and Subtalar Fusion Outcomes: A Propensity-Matched Cohort Study"
Host: Mark Easley (A)
Guests: Dr. Avani Chopra (B), Dr. Michael Anardi (C)
Date: December 23, 2025
Publisher: SAGE Publications (Foot & Ankle International)

Episode Overview

This episode centers on a pivotal new study examining how previous, same-side (ipsilateral) ankle or subtalar fusions affect the outcomes of additional fusions at adjacent joints. Using a large, longitudinal research database, the study differentiates between outcomes after a prior successful fusion versus a failed one, providing clarity on risk factors—especially nonunion rates—when subsequent fusion procedures are needed.

The discussion spans surgical techniques, database strengths and limitations, biological versus mechanical factors in joint healing, and practical strategies for optimizing surgical outcomes. The episode offers both a deep dive into the study’s methodology and findings and personal perspectives from experienced academic surgeons.

Key Discussion Points & Insights

1. Study Purpose and Major Findings

• Objective: To determine whether prior ipsilateral ankle or subtalar arthrodesis affects nonunion risk during subsequent adjacent joint fusion.
• Key Result:
  • Successful prior fusion does NOT increase nonunion risk for subsequent, adjacent joint fusion.
  • Failed prior arthrodesis dramatically increases subsequent nonunion risk.
• Notable Quote:

  "...a successful prior fusion does not increase the risk of non union in a subsequent adjacent fusion. However, a failed prior arthrodesis does dramatically raise the risk of non union of a subsequent adjacent fusion."
  — Dr. Chopra [01:18]

2. Current Surgical Techniques

• Dr. Anardi describes evolving toward minimally invasive approaches:
  • Use of smaller incisions and careful soft tissue handling, inspired by basic science advances regarding periosteum and stem cells.
  • Preference for burrs in joint preparation and limited stripping/osteotomies to preserve biology.
  • For ankle fusions: anterior medial arthrotomy, minimal fibular resection, use of compression screws, and grafting as appropriate.
  • Subtalar fusions involve sinus tarsi incision, burr and curette prep, and cannulated screw fixation.
• Notable Quote:

  "...I sort of jumped into joint prep with the bur...I think that's relevant in protecting the soft tissue envelope..."
  — Dr. Anardi [02:18]

3. Database Methodology & Rationale

• Databases Used:
  • TriNetX Research Network (main study): Enables longitudinal follow-up, essential for tracking sequential surgeries.
  • National Readmissions Database (NRD): Provides large sample size but limited to one calendar year.
• Advantages: Allow rare event study, overcome single-center limitations, facilitate statistically robust comparisons for uncommon procedures.
• Notable Quote:

  "...using these databases...overcome the rarity of certain procedures, complications and reliable study trends and risk factors that would otherwise be impossible to evaluate."
  — Dr. Chopra [04:48]

4. Implications: Failure of Prior Arthrodesis and Comorbidities

• Patients requiring both ankle and subtalar fusion often have more comorbidities (e.g., diabetes, higher BMI, etc.).
• Propensity-score matching was employed to balance for comorbidities across groups, ensuring reliable comparisons.
• The elevated risk for nonunion after a failed arthrodesis persists despite matching, indicating the failure itself is the primary risk driver, not just patient comorbidities.
• Clinical Implication: These patients should be considered for fusion-enhancing techniques—such as bone grafts and biologics—proactively.
• Notable Quote:

  "...even after matching, we still found a significantly higher nonunion rate in patients whose initial arthrodesis had failed. Which strongly suggests that it's the failure rather than the medical comorbidities alone..."
  — Dr. Chopra [09:12]

5. Challenges with Previous Literature

• Earlier studies found higher nonunion rates after consecutive fusions, but typically lacked:
  • Differentiation between healed and failed prior arthrodesis.
  • Sufficient sample size, granular data, or standardized imaging.
• Newer techniques (minimally invasive prep, biologics like PDGF, improved fixation) may influence outcomes.
• Notable Quote:

  "...technology has changed in our understanding of biology and some of our biologics have changed substantially...this paper at least will question that sort of old dogma..."
  — Dr. Anardi [11:31]

6. Reliability, Limitations, and Interpretability of Big Data

• TriNetX lacks direct imaging/patient-reported outcomes, relying instead on diagnostic codes for nonunion.
• Documentation of nonunion in records is expected to be reliable given its implications for further management and coding.
• Notable Quote:

  "...the threshold for documenting nonunion is high, which makes it a reasonable, reliable proxy at a population level..."
  — Dr. Chopra [15:18]

7. Evolving Surgical Strategies & Future Data Needs

• Dr. Anardi highlights personal choices for high-risk cases:
  • Use of compressive hindfoot nails, additional screws, PDGF (when appropriate), gradual mobilization, and rigorous casting/bracing protocols.
  • Techniques for optimal joint prep and biological augmentation, such as careful burring, harvesting autograft slurry, and reimplantation with biologic agents.
• Call for the future: Greater granularity in national databases (procedure details, implant types, biologic usage) for stronger conclusions.
• Notable Quote:

  "...if we're correct in our guess that it is more biology not stripping the periosteum...I would love additional data...it would really make this an even better paper."
  — Dr. Anardi [17:26]

8. Statistical Methods: Propensity-Score Matching

• Used to control for baseline differences and ensure fair, robust comparisons between patients with and without prior fusion.
• Notable Explanation:

  "This is a statistical technique...that reduces the impact of confounding variables to ensure balanced comparisons between the cohorts."
  — Dr. Chopra [22:23]

Notable Quotes & Memorable Moments

• Challenging Dogma:

  "This paper...will question that sort of old dogma..."
  — Dr. Anardi [11:31]

• Clinical Takeaway:

  "...a patient with a non union and you're doing ipsilateral fusion still requires a lot of care and a lot of attention and meticulous surgery and aftercare to get a good result."
  — Dr. Anardi [25:10]

• Fun Segment—Prognosticating Football:

  "I will make a bold prediction that Penn State will be victorious...final score, 35 Nittany Lions, 14 Scarlet Knights."
  — Dr. Anardi [24:02]

• Chocolate Humor:

  "Absolutely. There's no question about it. The highlight of Hershey is the chocolate."
  — Dr. Chopra [24:55]

Timestamps for Key Segments

• Introduction & Study Summary: [00:03]–[02:06]
• Surgical Technique Discussion: [02:18]–[03:51]
• Database Methodology & Strengths: [03:51]–[06:26]
• Question on Prior Clinical Experience & Motivation: [06:26]–[08:14]
• Role of Comorbidities vs. Failure in Nonunion Risk: [08:14]–[10:21]
• Comparing Study Results to Previous Literature: [10:21]–[14:05]
• Reliability of Database Approach: [14:05]–[16:07]
• Detailed Technique for Challenging Cases: [17:26]–[22:08]
• Explanation of Propensity-Score Matching: [22:08]–[23:17]
• Fun—Football & Chocolate: [23:17]–[25:00]
• Closing Remarks: [25:10]–[26:14]

Conclusion & Take-Home Messages

• Successful prior ipsilateral arthrodesis does not worsen nonunion risk after a subsequent fusion at an adjacent joint.
• Failed prior arthrodesis remains a major nonunion risk factor, regardless of comorbidity burden.
• Modern minimally invasive surgical approaches and biologics may be contributing to better outcomes than historically reported, but more granular data are needed.
• Large databases are invaluable for rare-event and multicenter research, but should be interpreted with awareness of their limitations.
• Surgeons should approach patients with prior failed fusions with maximized biological and mechanical support to optimize outcomes.

Final Takeaway:
This large, multicenter study is a step toward challenging outdated notions regarding sequential joint fusions in the foot and ankle. It supports the use of current best practices and careful patient optimization, especially for those with a history of nonunion, and highlights the ongoing need for more nuanced, procedure-specific data in surgical research.