Flexor Hallucis Longus Tendinitis is an injury more often seen in athletes, dancers, and gymnasts who are doing repetitive motions using the Flexor Hallucis Longus tendons. The Flexor Hallucis Longus tendon allows you to rise up on your toes. When you are doing this motion repetitively and overusing that tendon, it tends to get injured.
The patient typically will present with pain that’s over the inside of the foot (behind the small bone on the inside of the ankle, the medial malleolus), they can have pain underneath their first metatarsal in the foot, or a little bit distal to that. Often they will have pain when they’re trying to go up on their toes. For athletes, it’s more common that any kind of running activity will exacerbate that.
How is Flexor Hallucis Longus (FHL) Tendinitis Diagnosed?
When doing a physical examination for the foot and ankle pain in general, we do a normal test of muscle strength for the foot and ankle muscles, we do a sensory exam and test the reflexes in the lower extremities. A provocative maneuver specifically for FHL tendinitis involves testing the tendon when it is taught versus when it is released. So that’s called a Tomasen test, this is just specific for FHL tendinitis. So you’ll have the patient flex their foot and big toe. Usually they will have restricted range of motion and pain. That is considered a positive Tomasen test. When you allow the patient to release the foot and go into plantarflexion and point the foot, then they’ll have better range of motion of the big toe. This occurs because when you are putting the foot into dorsiflexion, you are really making that tendon taught.
As the tendon passes underneath, it passes through a tunnel called the tarsal tunnel, similar to the carpal tunnel in the wrist. As it passes through the tunnel time and time again, it sometimes can start to fray. When it starts to fray, patients can also feel a kind of locking or catching of the tendon that’s also usually painful because as a result of when it frays, the tendon gets swollen, irritated, inflamed, and fluid builds up around the area. The patient feels that swelling and feels the pain.
How is Flexor Hallucis Longus (FHL) Tendinitis Treated?
Treatment for FHL tendinitis is to relieve the pressure off of that tendon. First really is to protect that area, to rest the feet if at all possible, and to use good anti-inflammatories. Those can be natural anti-inflammatories such as ice after any kind of activity, to oral anti-inflammatories. Also, we now have image-guided injections, where, using an ultrasound machine, we can nicely localize that FHL tendon as it passes through the tunnel going in the ankle.
With the ultrasound, you can see the foot in real time so that the patient can go through those motions. After visualizing the tendon, you can put a little bit of medication, including steroid and anesthetic right around the tendon to reduce the inflammation. Usually that’s good to reduce the pain and reduce the inflammation in that area. And then, a combination of the modification of activities plus doing good exercises is usually sufficient to allow the tendinitis to heal.