When Should the Syndesmosis Screw Be Removed in the LON Method? 

In tibial lengthening surgeries performed with the LON (Lengthening Over Nail) method, a temporary syndesmosis screw may be used to ensure balanced alignment between the tibia and fibula. This screw provides stability during the distraction phase, especially when the fibula does not lengthen at the same rate as the tibia.

One of the most common questions patients ask is:

“When will the syndesmosis screw be removed?”

In this article, we explain the purpose of the syndesmosis screw, the ideal timing for removal, and situations in which it may be kept temporarily.

Why Is a Syndesmosis Screw Used?

During LON tibial lengthening, the fibula may migrate upward or fail to maintain proper alignment. The syndesmosis screw is used to:

• Prevent upward migration of the fibula
• Maintain distal tibiofibular stability
• Protect the ankle joint during lengthening
• Ensure coordinated tibia–fibula movement

It functions as a temporary stabilizing device.

When Should the Syndesmosis Screw Be Removed?

The most widely accepted surgical principle is:

“When the external fixator is ready to be removed, the syndesmosis screw is usually removed at the same session.”

The reasons are clear:

• The tibial regenerate is sufficiently consolidated.
• The fibula osteotomy is usually healed.
• The intramedullary nail now provides full stability and load bearing.
• The fibula no longer requires restriction.
• Keeping the screw for too long increases the risk of screw breakage.

Therefore, removing the syndesmosis screw at the time of fixator removal is both practical and safe.

When Is Removal Recommended?

Removal is generally advised when:

• The external fixator removal phase has been reached,
• Tibial bone consolidation appears solid on X-rays,
• The patient feels rotational limitation or ankle discomfort,
• The screw causes pain or irritation during walking,
• There is a risk of the screw breaking if left in place longer.

A broken screw is significantly more difficult to remove and may cause additional morbidity. Proper timing prevents this complication.

When Might the Screw Be Temporarily Kept?

In rare cases, the syndesmosis screw may be left in temporarily if:

• The tibial regenerate is weak or borderline,
• The fibula osteotomy shows delayed healing,
• Residual ankle instability is suspected,
• The fixator removal would otherwise be premature.

These are exceptions. Most patients do not require the screw to stay in place beyond the fixator removal stage.

Expert Surgical Approach

In limb lengthening surgery, the syndesmosis screw serves as a temporary support during distraction. Once the tibia has healed and the external fixator removal is planned, the screw has typically completed its function.

This approach provides several advantages:

• Restores natural ankle rotation,
• Improves gait mechanics and comfort,
• Eliminates the risk of screw breakage,
• Reduces unnecessary implant retention.

Both clinical experience and scientific literature support the practice of removing the syndesmosis screw at the same time as the external fixator.

FAQ: Will My Ankle Become Unstable After Removing the Screw?

No. If the tibia is healed and the fibula is stable, removing the screw does not cause ankle instability.

Stability at this stage comes from the intramedullary nail, the healed bone, and surrounding soft tissues—not from the screw.

Conclusion

The syndesmosis screw used during LON tibial lengthening is a temporary device. Once the tibia has consolidated and the external fixator removal phase has been reached, the screw is usually removed in the same surgical session.

While individual assessment is important, evidence and surgical experience show that this approach offers safer and more functional outcomes.