Sinus Tarsi Syndrome

Anatomy

• Funnel-shaped sinus
• Laterally based, leading into narrower tarsal canal

Boundaries

• Anterior: Talocalcaneonavicular joint
• Posterior: Posterior facet subtalar joint
• Inferior: Calcaneus and Extensor Digitorum Brevis (EDB)
• Superior: Talus

Contents

• Blood vessels supplying the talus
• Intraosseous talocalcaneal ligament
• Origin of inferior extensor retinaculum
• Nerve branches

Aetiology

• Nerve irritation, vascular engorgement resulting in pain
• Possible causes:
  • Fibrous talocalcaneal coalition
  • Subtalar instability
  • Subtalar arthritis
  • Intraosseous ligament tear

Clinical Presentation

• Usually a history of ankle injury
• Pain over the lateral aspect of the hindfoot
• Pain on varus tilt
• Pain on uneven ground
• 50% have ankle instability or pain

Imaging

X-ray (XR)

• Broden’s view, Stress views & Lateral
• Subtalar degenerative disease
• Laxity on stress testing

MRI

• Inflammation in the sinus tarsi
• Intraosseous talocalcaneal ligament rupture

Management

• Activity modification, NSAIDs, and rest
• Steroid Injection
  • Usually effective for most patients
  • If ineffective, has diagnostic value
• Surgical excision of tarsal sinus contents and debridement
• Correction of underlying pathology, including:
  • Fibrous coalition
  • Instability
  • Subtalar arthritis