FHL Tendon Transfer (Achilles Augmentation)
The flexor hallucis longus (FHL) tendon is transferred to augment a chronically torn or degenerated Achilles tendon. It restores plantarflexion strength when primary repair is not enough.
Medically reviewed by Michael G. Lyons, DPM — Board-Certified Foot and Ankle Surgeon
Written and reviewed by the physicians of Foot Health Centers, Hernando & Southaven, MS. Meet our doctors
- Chronic Achilles rupture with significant tendon gap
- Severe Achilles tendinosis with extensive debridement
- Re-rupture after primary repair
The FHL tendon is harvested and rerouted through the calcaneus, securing it to provide a strong, vascularized replacement or augment for the Achilles.
- Splint then boot for 6–8 weeks
- Physical therapy starting 8 weeks
- Return to activity 6–9 months
- Wound healing
- Sural nerve injury
- Loss of great toe push-off (rare)
- Infection
Conditions this procedure treats
Achilles Tendon Rupture
An Achilles tendon rupture is a complete tear of the tendon, often felt as a sudden "pop" in the back of the ankle during sports or sudden push-off. Rapid diagnosis matters — repair is best performed within the first 2–3 weeks.
Learn moreInsertional Achilles Tendinopathy & Haglund's Deformity
Pain where the Achilles tendon attaches to the heel — often with a bony prominence ("pump bump") — is called insertional Achilles tendinopathy. It can include calcification of the tendon and irritation of the retrocalcaneal bursa.
Learn moreFrequently asked questions
Will losing the FHL affect my big toe?
Most patients have full great toe function. The transfer is well tolerated.
Request a surgical consultation
Tell us a little about what's going on — our team will follow up to schedule.
Ready to Get Relief?
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