Emergent Care / Stabilization: Assess the patient for additional injuries and for pain control, and order x-rays to evaluate for concomitant fractures. Immediate orthopedic surgery consult is warranted as urgent reduction of the joint is necessary to avoid potential soft tissue or neurovascular compromise.

Causes / typical injury mechanism: Subtalar joint dislocations are relatively rare injuries, typically caused by high-energy traumatic injury. Etiologies can include motor vehicle crashes, sport injuries, and falls from a height.

Classic history and presentation: Patients will present with a recent history of high-energy trauma and pain in the hindfoot, with a visible deformity of the ankle. Medial dislocations are more common than lateral dislocations; it is more frequently a closed injury, but open dislocations do occur given the traumatic nature of the injury.

Prevalence:

• Most commonly occurs in younger males with exposure to high-energy trauma
• Accounts for 1% of all dislocations

Risk factors:

• Exposure to high-energy trauma
• Prior dislocation or joint hypermobility

Pathophysiology:

• Medial dislocations are more common than lateral dislocations due to anatomic obstacles. Medial dislocations are associated with lower-energy mechanisms, and with basketball players.
• Lateral dislocations are higher energy, more often open injuries with, at times, extensive soft tissue damage.
• Concomitant fractures of talar bones are not uncommon at the talus and calcaneus in particular (periarticular fractures).

Grade / classification system: 

• Open versus closed
• Medial versus lateral dislocation (anterior and posterior dislocations are very rare)