Posterior subtalar dislocation

Area of Science:

• Orthopedics
• Traumatology
• Podiatry

Background:

• Subtalar dislocation is an uncommon foot injury, with posterior dislocations being exceptionally rare.
• This injury involves simultaneous talocalcaneal and talonavicular joint dislocation, sparing tibiotalar and calcaneocuboid articulations.
• Often associated with fractures and rotational components, subtalar dislocations present significant deformity.

Observation:

• A case of pure posterior subtalar dislocation in an 80-year-old male after a motorcycle accident.
• Radiographs confirmed talonavicular and talocalcaneal joint dislocation with posterior calcaneal displacement.
• Absence of medial/lateral or rotational displacement suggested pure hyperplantar flexion trauma.

Findings:

• The presented case highlights a rare posterior subtalar dislocation.
• The mechanism appears to be pure hyperplantar flexion, leading to posterior calcaneal displacement.
• No associated fractures or rotational components were observed in this specific case.

Implications:

• Hypothesizes that prolonged hyperplantar flexion can cause subtalar ligament weakening and rupture.
• Suggests this mechanism is possible with good bone quality and distal force application on the navicular bone.
• This case expands understanding of subtalar dislocation etiology, particularly pure posterior variants.