Podcast Summary: FAI February 2025 – Correction Target of Supramalleolar Osteotomy for Early Varus Ankle Arthritis: Is Overcorrection Necessary?

Podcast: Foot & Ankle International (FAI)
Host: Mark Easley (A)
Guest: Dr. Wu Chun Li (B), Senior Author, Seoul Foot and Ankle Center
Date: February 10, 2025

Episode Overview

This episode delves into the findings of Dr. Wu Chun Li’s lead article for February 2025 in Foot & Ankle International, focusing on the alignment strategy for supramalleolar osteotomy (SMO) in patients with early varus ankle arthritis. The central debate: Is the long-standing orthopedic practice of overcorrection necessary, or can neutral correction suffice for optimal outcomes? Dr. Li shares clinical insights, surgical pearls, and personal perspectives, grounded in both rigorous research and extensive practical experience.

Key Discussion Points & Insights

1. Summary of the Study and Its Findings

[01:35]

• Dr. Li clarifies that the study is not an overview of all joint preservation surgeries but focuses specifically on medial open wedge SMO in early varus ankle arthritis.
• Only patients with Takakura stage 2 or 3A arthritis and talus tilt less than 8° were included.
  • "I am reiterating that this article only deals with early varus arthritis with small Taylor tilt which was less than 8 degrees." [01:52, Dr. Li]
• Patients were grouped by post-op alignment:
  • Neutral: Medial distal tibial angle (MDTA) < 94°
  • Overcorrected: MDTA ≥ 94°
• No significant differences in clinical or radiologic outcomes between neutral and overcorrected groups.
  • Conclusion: "Overcorrection of the tibia platform seems not necessary." [03:50, Dr. Li]

2. Takakura Staging: Clinical Relevance

[04:24]

• Stage 2: Medial joint space narrowing at the medial gutter and/or tibia-talar dome, without obliteration.

• Stage 3A: Medial gutter obliteration, sometimes with preserved joint space elsewhere.

  "Stage 2 shows medial joint space narrowing... Stage 3a means medial gutter obliteration..." [05:01, Dr. Li]

3. Natural History of Mild Varus Alignment

[05:39]

• Not all varus alignments progress, but medial translation of the talus signifies risk for deterioration.

• In Asian populations, certain limb alignments predispose to varus ankle arthritis more than in the West.

  "Medial translation is caused by medially directed shear force. Therefore it would deteriorate to stage 3A with complete disappearance of the medial gutter." [07:13, Dr. Li]

4. Key Surgical Techniques

[08:50]

• Osteotomy performed just proximal to the syndesmosis, preserving lateral cortex for ‘lateral hinge’ effect; no bone grafts; plate fixation is used.
• Stepwise details to avoid cracking the lateral cortex when opening the wedge, using a pre-bent plate and precise screw technique.
  • "I cut the bone almost 3,4 of the circumference so the lateral cortex is preserved... One of the key points to obtain correction without complete osteotomy is the pre bending of the tibial plate." [09:55, Dr. Li]
• Prefers non-locking plates for adjustability.

5. Indications for Associated Procedures

[12:06]

• Isolated SMO is favored in most cases for early stages.

• Calcaneal osteotomy: Reserved for patients with significant hindfoot valgus, not for talar tilt/medial translation.

• Tendon transfers (e.g., PTT): Only for paralytic origins, not reliable otherwise.

• Lateral ligament repair: For impingement prevention, but not as a standalone correction.

  "Lateral closing osteotomy Calcaneal osteotomy has less ability to correct the coronal plane alignment..." [12:48, Dr. Li]

6. Soft Tissue Procedures and Medial Release

[15:10]

• Dr. Li remains skeptical about tendon transfer or ligament balancing for lasting correction.
  • "I do not trust the validity of soft tissue procedures like tendon transfer or ligament balancing." [15:18, Dr. Li]
• Avoids medial deltoid release as over-correction or instability may result without true long-term benefit.

7. Radiographic Analysis and Weight-Bearing CT

[16:50]

• Recent research includes advanced CT analysis, recognizing three-dimensional deformities in more advanced disease.

• Prospective studies using weight-bearing CT are being considered for greater insight.

  "I try to correct the deformity 3 dimensionally in more advanced arthritis than just medial open wedge supramalleolar osteotomy..." [18:11, Dr. Li]

8. Indications for Dome Osteotomy

[20:00]

• Dome-type SMO favored in advanced cases with substantial axial rotation and talar tilt.

• Dome osteotomy allows for correction in axial rotation—not just coronal plane—transforming internal rotation and addressing medial impingement.

  "Actually, I'm doing dome type supramalleolar osteotomy as frequently as medial open wedge... With dome types... the talus is externally rotated in axial plane..." [20:00, Dr. Li]

Notable Quotes & Memorable Moments

• On Overcorrection
  "Overcorrection of the tibia platform seems not necessary." [03:50, Dr. Li]
• On Surgical Pearls
  "One of the key points to obtain correction without complete osteotomy is the pre bending of the tibial plate." [10:12, Dr. Li]
• Limitations of Soft-Tissue Procedures
  "I do not trust the validity of soft tissue procedures like tendon transfer or ligament balancing." [15:18, Dr. Li]
• Comparing SMO and High Tibial Osteotomy (HTO)
  "Supramolar osteotomy is basically different from high tibial osteotomy... HTO was developed to unload the medial compartment of the knee... In contrast, the bony segment distal to the SMO is only about 3 cm." [21:53, Dr. Li]

Cultural Interlude: Life in Gangnam

[16:22]

• Dr. Li explains ‘Gangnam’ means “south of the Han River”. Most shopping/entertainment is centered here.
  • "Everything's new and road is wider than northern part of the Seoul. And usually the shopping and entertainment areas are popular attractions." [16:22, Dr. Li]
• Fun moment: "It is long time since the horse dance was popular... it is not common to see it even in Korea." [21:24, Dr. Li]

Final Takeaways

• Neutral alignment is sufficient; traditional overcorrection isn’t necessary for early varus ankle arthritis with SMO.
• Careful patient selection (Takakura 2/3A, talar tilt <8°) and precise surgical technique matter most.
• SMO and HTO are fundamentally different procedures; one cannot extrapolate outcomes from the knee to the ankle.
• Dr. Li advocates for continued research using newer imaging modalities and for further study of dome osteotomies in advanced cases.

"SMO is different from HTO and the result of this study support that overcorrection of the tibial platform into valgus does not lead to more correction of the talar tilt or radiological staging." [23:19, Dr. Li]

For clinicians treating early varus ankle arthritis, this episode offers practical wisdom and nuanced, evidence-backed guidance on the judicious application of supramalleolar osteotomy.