Define Pilon (Plafond) Fracture. Describe its clinical features, investigations and management.

Definition

A pilon (plafond) fracture is a fracture of the distal tibial articular surface (the plafond) caused by high-energy axial loading that drives the talus up into the tibia (a fall from height or RTA). It is distinct from a rotational ankle fracture: there is severe articular comminution and marked soft-tissue injury. (‘Pilon’ = pestle, the talus acting as a pestle against the tibial mortar.)

Clinical Features

A grossly swollen, deformed distal leg after a high-energy injury, often with fracture blisters and threatened or open skin. Assess the neurovascular status and screen for associated axial injuries (calcaneus, tibial plateau, spine). The key contrast is with a rotational ankle fracture: a pilon results from axial compression (talus driven upward), so it damages the weight-bearing articular surface with metaphyseal impaction and far greater soft-tissue injury, whereas a rotational fracture spares the plafond and is comparatively low-energy. This difference dominates both management and prognosis.

Investigations

AP, lateral and mortise radiographs and, essentially, a CT scan to define the articular fragments and plan reconstruction (Ruedi-Allgower classification).

Management

Because the soft-tissue envelope is so badly injured, management is usually staged: initial spanning external fixation (‘travelling traction’) to restore length and protect the skin, then delayed definitive ORIF once swelling subsides and the skin wrinkles. The goals are an anatomically reduced joint surface, restored alignment and stable fixation. Severe open or non-reconstructable injuries may need definitive external fixation or, late, ankle arthrodesis.

Classification & Complications

The Ruedi–Allgöwer classification grades the injury by articular displacement and comminution (I undisplaced, II displaced with moderate comminution, III severely comminuted). Pilon fractures are notorious for complications: wound breakdown and deep infection (the dominant early problem, driven by the soft-tissue injury), stiffness, post-traumatic osteoarthritis of the ankle from articular damage, malunion and non-union. Outcomes correlate strongly with the initial soft-tissue and articular injury.

Soft tissue condition dictates the timing of definitive fixation.

• High-energy axial injury of the distal tibial articular surface (plafond).
• Severe articular comminution + major soft-tissue injury (fracture blisters).
• CT is essential for planning.
• Stage it: span with external fixator first, then delayed ORIF once soft tissues recover.