Achilles tendon injuries, particularly when they become chronic, can be difficult to treat. In cases where the Achilles tendon is severely ruptured and traditional methods cannot repair the damage, flexor hallucis longus (FHL) tendon transfer surgery offers a solution. This surgery involves using the tendon from a muscle in the foot to help repair the damaged Achilles tendon, improving function and reducing pain.
What is Flexor Hallucis Longus (FHL) Tendon Transfer?
The FHL tendon transfer procedure is used to treat chronic Achilles tendon ruptures, particularly when the tendon is too damaged to heal on its own. The FHL tendon, which is located near the big toe, is harvested and re-routed to replace the damaged part of the Achilles tendon. This procedure is typically used when the Achilles tendon has been torn for several weeks or months and other methods are unlikely to succeed.
Why is FHL Tendon Transfer Used?
Chronic Achilles tendon rupture often occurs when the initial injury is not treated promptly, leading to a retracted tendon with a large gap between the two ends. Traditional tendon repairs might not work in these cases. The FHL tendon, which is strong and capable of compensating for the damaged tendon, is used to restore the function of the foot and ankle.
How is the Surgery Performed?
The surgery involves the following key steps:
- Harvesting the FHL Tendon: The patient is positioned so that the surgeon can access the tendon through a small incision near the ankle. The FHL tendon is carefully detached from its attachment to the big toe.
- Preparing the Achilles Tendon: The damaged Achilles tendon is cleaned and prepared for the transfer. The surgeon creates a tunnel in the heel bone (calcaneus) to insert the FHL tendon.
- Attaching the FHL Tendon: The harvested FHL tendon is threaded through the tunnel and sutured to the Achilles tendon. This creates a new connection that allows the FHL tendon to perform the same functions as the Achilles tendon, such as helping with walking and running.
Post-Surgery Recovery
After the surgery, the patient is required to rest the foot and avoid putting weight on it for several weeks. Typically, a plaster cast or a walking boot is used to maintain the ankle in a slightly bent position (5° to 10° of plantar flexion). Gradual rehabilitation begins after a few weeks, and patients are encouraged to perform ankle exercises to restore mobility and strength.
What are the Benefits of FHL Tendon Transfer?
- Improved Strength and Function: The main goal of the surgery is to restore the plantar flexion (downward movement of the foot), which is essential for walking, running, and performing other everyday activities. Studies have shown that patients can regain nearly normal strength in the affected leg after surgery.
- Satisfaction with Results: The majority of patients are satisfied with the results of the surgery. Many report returning to their normal activities with minimal discomfort.
- Safe and Reliable: FHL tendon transfer is considered a safe procedure, with a low risk of major complications when performed by experienced surgeons.
What are the Risks and Complications?
As with any surgery, there are potential risks involved. Some of the most common complications include:
- Infection: Some patients may develop infections at the site of the surgery. These can usually be treated with antibiotics.
- Weakness of the Big Toe: After the FHL tendon is transferred, patients may experience a slight reduction in the strength of their big toe, which could affect balance. However, most patients do not report significant problems with this.
- Clawing of Smaller Toes: In some cases, the toes may become curled (claw toes) due to changes in tendon tension. This can usually be managed with further surgery if necessary.
Long-Term Outcomes
A study involving 28 patients who underwent FHL tendon transfer showed a significant improvement in ankle and foot function. The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, which assesses the overall function of the foot and ankle, improved substantially after surgery. Patients reported an average score of 90.4 out of 100 at their final follow-up, indicating good recoveryonclusion
FHL tendon transfer is a highly effective treatment for chronic Achilles tendon ruptures with significant defects. Although the surgery is not without risks, such as the potential for reduced strength in the big toe or infection, it offers a reliable solution for restoring function in patients with severe Achilles tendon injuries. The procedure allows many patients to return to their normal daily activities and is a trusted option when other treatments have failed.
Do you have more questions?
Q. What is Flexor Hallucis Longus (FHL) Tendon Transfer for Achilles Tendon Repair?
A. FHL tendon transfer is a surgical procedure used to treat chronic Achilles tendon ruptures by rerouting the flexor hallucis longus tendon from the big toe to replace the damaged Achilles tendon, improving foot and ankle function.
Q. How is FHL Tendon Transfer surgery performed?
A. The surgery involves harvesting the FHL tendon from near the big toe, creating a tunnel in the heel bone, and reattaching the tendon to the damaged Achilles tendon, allowing the FHL tendon to compensate for the Achilles tendon’s function.
Q. Why is FHL Tendon Transfer used?
A. It is used when the Achilles tendon is too damaged to heal through traditional repair methods, typically after chronic ruptures or when there is a large gap between the two ends of the Achilles tendon.
Q. What are the benefits of FHL Tendon Transfer?
A. The procedure restores the function of the Achilles tendon, improving plantar flexion and helping with walking, running, and everyday activities. Patients often report regaining nearly normal strength after surgery.
Q. What are the risks and complications of FHL Tendon Transfer?
A. Risks include infection, weakness of the big toe, and possible clawing of smaller toes. These complications are generally manageable, but additional surgery may be needed in some cases.
Q. How long does it take to recover from FHL Tendon Transfer surgery?
A. Recovery involves avoiding weight-bearing for several weeks, followed by gradual rehabilitation. Most patients regain full function within several months, though full recovery may take up to a year.
Q. Can I walk immediately after FHL Tendon Transfer surgery?
A. No, you will need to rest the foot and avoid putting weight on it for several weeks. After that, gradual weight-bearing and physical therapy will help restore function.
Q. Is physical therapy necessary after FHL Tendon Transfer?
A. Yes, physical therapy is essential to help restore strength, flexibility, and proper mobility to the foot and ankle after surgery.
Q. Who is a good candidate for FHL Tendon Transfer?
A. This procedure is ideal for patients with chronic Achilles tendon ruptures who have not had successful outcomes with other treatments, particularly when the tendon is too damaged to repair using traditional methods.
Q. What is the long-term outcome of FHL Tendon Transfer?
A. Most patients experience significant improvements in function, with many able to return to normal activities. However, the long-term success depends on the patient’s adherence to rehabilitation and recovery protocols.
Q. How long does the FHL Tendon Transfer procedure take?
A. The surgery typically takes 1 to 2 hours, depending on the complexity of the Achilles tendon injury and the specific surgical approach used.
Q. Will there be any visible scars after FHL Tendon Transfer?
A. Yes, there will be a small scar where the tendon is harvested and another where the tendon is reattached to the Achilles. These scars typically heal well and become less noticeable over time.
Q. Can FHL Tendon Transfer be performed on both feet?
A. While it is possible to perform the procedure on both feet, it is generally done one foot at a time to allow for proper healing and minimize complications.
Q. Will I need to wear a boot or cast after surgery?
A. Yes, you will likely need to wear a walking boot or cast for several weeks to protect the foot and allow the tendon to heal properly.
Q. Is FHL Tendon Transfer a permanent solution for Achilles tendon rupture?
A. For most patients, FHL tendon transfer provides a long-term solution by restoring functionality to the Achilles tendon. However, full recovery depends on proper rehabilitation, and some patients may require additional treatments for optimal results.
Dr. Mo Athar
