A Chopart injury is a dislocation of the talonavicular and calcaneocuboid joint that may include a combination of:
Ligamentous injuries to the talonavicular and calcaneocuboid joints
Fractures of the talus, calcaneus, cuboid, and/or the navicular
There is swelling, bruising, and point tenderness.
Complete intraarticular fractures may be associated with deformity. The higher-energy injuries (MVA or industrial/crush) are associated with significant soft-tissue trauma and other injuries to the foot; deformity is more likely to be present.
In the multi-injured patient, foot fractures are often overlooked and are picked up on the secondary survey. In the unconscious patient, one must rely on a careful physical examination. Swelling, crepitus, or a deformity are suggested signs of underlying injury and should be followed up with appropriate x-rays.
Around 30-40% of these injuries are underdiagnosed at the first instance. Therefore a high index of suspicion is required.
Lateral x-ray showing a simple Chopart joint injury
This case shows a severe Chopart injury in oblique and lateral x-rays.
CT images are routinely recorded, both for seeing the whole extent of the injury as well as to prepare a treatment plan.
Mechanism of injury
These injuries may occur in the following ways:
Lateral stress (abduction) in combination with axial stress. This typically results in a compression injury of the calcaneocuboid joint and a distraction injury of the talonavicular joint.
Medial stress (adduction) in combination with axial stress. This typically results in a distraction injury of the calcaneocuboid joint and a compression injury of the talonavicular joint.
Plantar stress (eg, heavy object falling on the foot)
There may be associated soft tissue, neurovascular, bony, and ligamentous injuries in both the forefoot, anterior midfoot, and ankle.