Tendonitis in the Ankle and Foot

Tendonitis in the Ankle and Foot: Understanding, Diagnosis, and Treatment

Tendonitis—or more precisely, tendinopathy—is a common cause of foot and ankle pain. It refers to a spectrum of tendon disorders characterized by pain, swelling, and functional impairment. Tendonitis can affect any of the four major compartments of the ankle: posterior, medial, lateral, and anterior. Understanding the anatomy, clinical presentation, and treatment options for each type is essential for proper care and recovery.

What Is Tendonitis?

Tendonitis involves the inflammation or degeneration of tendons—fibrous tissues connecting muscles to bones. In modern medical literature, “tendinopathy” is preferred as it includes both inflammatory and degenerative conditions. Patients typically present with:

  • Localized pain
  • Swelling around the tendon
  • Pain during movement, especially when stretching or contracting the involved muscle​

Tendinopathies may result from:

  • Overuse or repetitive stress (mechanical causes)
  • Trauma
  • Inflammatory conditions (e.g., arthritis)
  • Iatrogenic factors (e.g., medication-induced)​
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Posterior Compartment: Achilles Tendinopathy

Anatomy

The Achilles tendon (calcaneal tendon) is the largest tendon in the human body, formed by the gastrocnemius and soleus muscles. It inserts into the calcaneus (heel bone) and plays a crucial role in walking, running, and jumping.

Clinical Presentation

  • Mid-substance tendinopathy: Pain 2–6 cm above insertion. Swelling and tenderness over tendon body.
  • Insertional tendinopathy: Pain at the heel, especially with pressure or activity.
  • Nodular tendinopathy: Palpable, painful nodule.
  • Paratenonitis: Generalized swelling and sometimes crepitus (“snow-like” crackling on palpation).
  • Complete rupture: Inability to rise on toes; positive Thompson test (no foot movement when calf squeezed)​

Risk Factors

  • Running and jumping sports
  • Middle age
  • Fluoroquinolone or corticosteroid use
  • Rheumatic diseases (e.g., spondyloarthritis)
  • Metabolic conditions such as gout or chondrocalcinosis​

Medial Compartment: Tibialis Posterior and Flexor Tendon Disorders

Posterior Tibial Tendinopathy

Anatomy

The tibialis posterior muscle runs behind the medial malleolus and inserts into the navicular and cuneiform bones. It supports the arch and stabilizes the foot during movement.

Symptoms and Stages

  • Pain along the inner ankle
  • Flatfoot deformity (pes planovalgus)
  • “Too many toes” sign (toes visible from behind)
  • Difficulty performing heel raises

Stages range from:

  • Stage I: Mild pain, no deformity
  • Stage II: Flexible flatfoot
  • Stage III: Rigid deformity, lateral impingement pain​
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Causes

  • Common in overweight women aged 40–60
  • Flatfoot or valgus heel alignment
  • Rheumatoid arthritis or accessory navicular bone​

Treatment

  • Orthotics for arch support
  • Physical therapy with eccentric loading
  • Short-term immobilization
  • Surgery in advanced stages (e.g., tendon transfer, arthrodesis)​

Flexor Hallucis Longus (FHL) and Flexor Digitorum Longus (FDL)

Anatomy

FHL flexes the big toe and passes through the “knot of Henry” where it crosses the FDL in the midfoot. These tendons assist with toe movement and foot stability.

Symptoms
  • Pain with toe movement
  • Tenderness and crepitus
  • More common in ballet dancers and athletes​

Anterior Compartment: Tibialis Anterior Tendinopathy

Anatomy

The tibialis anterior tendon runs down the front of the shin and inserts into the medial cuneiform and first metatarsal. It dorsiflexes the foot and stabilizes the arch during gait.

Symptoms

  • Pain in the anterior ankle and medial midfoot
  • Night pain
  • Weakness with dorsiflexion
  • Positive stretch test: pain with passive plantarflexion and pronation​

Causes

  • Elderly men with degenerative changes
  • Overuse in runners
  • Shoe pressure or excessive walking

Treatment

  • Activity modification
  • Immobilization or ankle-foot orthosis
  • Physical therapy
  • Surgery if persistent​

Lateral Compartment: Peroneal Tendinopathy

Anatomy

The peroneus longus and brevis run behind the lateral malleolus and evert the foot. They stabilize the ankle during walking and running.

Symptoms

  • Pain behind the outer ankle
  • Swelling, tenderness, and crepitus
  • Pain with foot eversion and plantarflexion
  • Possible subluxation over the lateral malleolus​
    ​

Risk Factors

  • Varus heel alignment
  • Footwear issues
  • Running, especially with forefoot strike
  • Anatomical variations (e.g., shallow groove, accessory muscles)

Management

  • Lateral wedge orthotics
  • Immobilization
  • Physical therapy
  • Corticosteroid injections (ultrasound-guided)
  • Surgery in case of tears or dislocations​

Diagnosis: Clinical First, Imaging Second

A clinical exam remains the cornerstone:

  • Pain on direct palpation
  • Pain on passive stretch
  • Pain with resisted muscle contraction

Imaging (when needed):

  • X-rays: Bone abnormalities
  • Ultrasound: Dynamic tendon evaluation
  • MRI: Surgical planning or diagnosis clarification​

Conclusion

Tendonitis in the foot and ankle encompasses a range of conditions depending on the affected tendon. Accurate anatomical understanding, early diagnosis, and appropriate treatment can dramatically improve function and prevent chronic disability. Whether you’re an athlete, a runner, or someone experiencing unexplained ankle pain, seeking evaluation early ensures the best outcome.