FHL Tenosynovitis

Located in the tarsal tunnel, the flexor hallucis longus (FHL) is a tendon associated with the ankle and runs into the big toe (specifically the distal phalanx). It helps with flexing the big toe, plus pointing the toes and feet downwards, and also with elevation of the arch beneath the foot.

Symptoms of FHL Tenosynovitis

Spreading pain primarily found in the rear of the ankle, behind the bone, but not necessarily restricted to that area. The pain can be worsened during walking, sprinting or climbing activities and the ache felt throughout the ankle. Pushing off (such as in a race) is an especially painful motion. Some movements of the big toe or ankle might result in sharp pain and a clicking sensation. The area around the back of the ankle may feel slightly tender to the touch, though this is not universal due to the deepness of the tendon within the ankle. The ankle can become inflamed. Regular upward pointing of the big toe can prove difficult. Flexing the affected foot against weight or other resistance should replicate the pain of the condition. Symptoms generally improve during rest.

Causes of FHL Tenosynovitis

The causes of the injury can be complex but FHL tenosynovitis often arises in ballet dancers, who are required to perform intricate and intense foot movements over long periods. Other extreme repetition can also contribute to the injury, such as overuse from extending and flexing the foot or big toe over a long period of time or without the necessary stretches and warm ups to maintain such exertion. This can occur in many high impact sports if the athlete is not careful. Repeated trauma, such as direct blows to the rear of the ankle or the big toe in a contact sport, can also lead to deterioration in the FHL tendon.

Medical Treatment for FHL Tenosynovitis

Consult a doctor as soon as you experience symptoms similar to those listed above, and cease any stressful activities involving the feet. It is likely that the doctor will have to perform x-rays or other tests in order to properly diagnose the condition. This is essential because the injury is often confused with others because of similarities with conditions including tarsal tunnel syndrome, Achilles tendonitis and tibialis posterior tendonitis. They will also wish to investigate the possibility of a more serious tear to the tendon. Treatment depends on the severity of the injury, but anti-inflammatory painkillers are commonly prescribed along with a course of immobilisation for the affected foot. A cast may be used for this, and crutches can be necessary for a short time. In major cases an operation might be required to fully repair the FHL tendon.