What causes fhl tendonitis

What is FHL Tendonitis?

FHL tendonitis, medically known as tenosynovitis of the flexor hallucis longus tendon, is an inflammation of the tendon that runs along the inside of the ankle and into the big toe. The flexor hallucis longus (FHL) muscle is a critical component of the calf muscle group, responsible for flexing the big toe downwards. This action is essential for activities like pushing off the ground during walking, running, and jumping, as well as for maintaining balance.

When this tendon becomes inflamed, it can cause significant pain and discomfort, particularly in the area behind the medial malleolus (the bony prominence on the inside of the ankle) and extending into the sole of the foot and the big toe. The condition is often referred to by descriptive names such as 'jogger's foot' or 'dancer's tendonitis' due to its prevalence in these athletic populations.

What Causes FHL Tendonitis?

The primary culprit behind FHL tendonitis is overuse and repetitive strain. The FHL tendon is subjected to considerable stress during activities that involve repeated and forceful flexion of the big toe. This can happen in several ways:

Repetitive Motion and Overuse

Activities that demand continuous or intense use of the FHL tendon are the most common causes. These include:

• Running: Particularly with improper form, worn-out shoes, or running on hard surfaces, the repetitive push-off motion can strain the FHL tendon.
• Ballet Dancing: This is a classic cause. Dancers frequently perform relevés (rising onto the balls of the feet) and pointe work, which place extreme demands on the FHL tendon for stability and toe flexion. The constant pressure and repetitive movements can lead to inflammation.
• Other Sports: Sports involving jumping, sprinting, or quick changes in direction, such as soccer, basketball, and gymnastics, can also contribute to FHL tendonitis due to the forceful push-off required.
• Prolonged Standing or Walking: For individuals whose jobs require them to be on their feet for extended periods, especially on hard surfaces, cumulative stress can develop over time.

Sudden Increases in Activity

A sudden and significant increase in the intensity, duration, or frequency of physical activity without adequate rest and conditioning can overload the FHL tendon. This is often seen when:

• A runner suddenly increases their mileage or starts training for a race without a gradual progression.
• An individual returns to a sport after a period of inactivity and jumps back in at full intensity.
• A dancer increases their rehearsal hours or starts practicing more difficult choreography without proper acclimatization.

Biomechanical Factors and Foot Structure

Certain anatomical features and biomechanical issues can make an individual more susceptible to developing FHL tendonitis:

• Foot Pronation: Overpronation (excessive inward rolling of the foot) can alter the mechanics of the foot and ankle, placing abnormal stress on the FHL tendon.
• Anatomical Variations: Some individuals may have anatomical variations that predispose them to FHL tendonitis. This can include a thickened tendon sheath (the protective covering around the tendon), bony spurs (osteophytes) that impinge on the tendon, or an unusually long or prominent FHL tendon.
• Inadequate Footwear: Shoes that lack proper support, cushioning, or are worn out can contribute to abnormal foot mechanics and increased stress on the FHL tendon.

Trauma or Injury

While less common than overuse, direct trauma to the ankle or foot, such as a stubbed toe or a fall, can sometimes injure the FHL tendon and lead to inflammation, especially if the injury is not properly managed.

Degenerative Changes

As individuals age, tendons can become less flexible and more prone to injury. Degenerative changes within the FHL tendon can make it more susceptible to inflammation from everyday activities or minor stresses.

Symptoms of FHL Tendonitis

The hallmark symptom of FHL tendonitis is pain. This pain is typically felt:

• On the inside of the ankle, just behind the bony prominence (medial malleolus).
• It may radiate into the sole of the foot and towards the big toe.
• The pain is often worse during activities that involve pushing off the foot or flexing the big toe, such as walking, running, dancing, or even standing on tiptoes.
• Pain may be present at rest, especially after activity, and can be worse in the morning.
• Swelling and tenderness may be present in the affected area.
• A snapping or popping sensation may be felt or heard as the tendon moves, particularly during ankle or toe motion.

It's important to consult a healthcare professional for an accurate diagnosis and appropriate treatment plan if you suspect you have FHL tendonitis. Early intervention can help prevent chronic pain and more serious complications.