Pilon is a French term used to describe a fracture of the distal tibia usually characterized by high-energy traits, including dissociation of the articular surface from the tibia shaft.

• ○
  

  Destot coined the term pilon, as he thought that the distal tibial metaphysis resembled a pharmacist’s pestle.

Plafond is also a French term, described by Bonin, referring to the distal tibial articular surface as the roof (ceiling) of the ankle joint.

At the level of the ankle, the distal tibia is intimately associated with the fibula through strong ligamentous attachments.

• ○
  

  The attachments are as follows:

  
  
  
  
  • –
    

    Anterior inferior tibiofibular ligament

    
    
  • –
    

    Posterior inferior tibiofibular ligament

    
    
  • –
    

    Interosseous ligament

    
    
  • –
    

    Inferior transverse ligament

  
  

The articular surface of the distal tibia is concave in both the coronal as well as the sagittal plane.

The talus has the opposite geometry of the tibial plafond and therefore serves as a perfect template for assessing articular reduction of the distal tibia.

The concave tibial plafond provides ~ 40% more posterior than anterior coverage.

The pilon fracture usually has an anterolateral (Chaput) fragment and a posterolateral (Volkmann) fragment, which usually remain attached to the distal fibula segment by the anterior and posterior tibiofibular ligaments.

In the vast majority of pilon fractures, the fracture lines propagate from the fibular incisura laterally in the shape of a Y to exit anterior and posterior to the medial malleolus.

Comminution, which frequently occurs with high-energy pilon fractures, is most typically located in the anterolateral and central regions of the plafond.

There simply is not a lot of soft tissue around the distal tibia, as compared to more proximal parts of the leg.

• ○
  

  There is no muscle tissue to “cushion” or protect the bone if skin is injured.

The tendons of the anterior compartment, the dorsalis pedis artery, and the superficial and deep peroneal nerves can be encountered with anterior exposures at the level of the ankle joint.

The tendinous and neurovascular structures are covered proximally by the investing fascia of the anterior compartment and distally by the extensor retinaculum.

The superficial peroneal and saphenous nerves are superficial to the fascia.

• ○
  

  The superficial peroneal nerve pierces the fascia of the lateral compartment ~ 12 cm proximal to the ankle joint en route to provide sensation to a majority of the dorsum of the foot.

Anterolateral exposures for pilon fractures risk injury to the superficial peroneal nerve.

The dorsalis pedis and deep peroneal nerve are at risk with an anterior exposure.

• ○
  

  They run together in the pericapsular fat between the extensory digitorum and extensor hallucis longus tendons.

The tibial pilon fracture is a rare yet devastating injury.

Despite the best treatment, patients sustaining high-energy pilon fractures generally do not return to their previous state of general health or function.

• ○
  

  After recovery from pilon fractures, many patients continue to have debilitating pain and ankle stiffness (Babis et al 1997, Sands et al 1998, Pollak et al 2003).

Fortunately, pilon fractures compose a minority of tibia or lower extremity fractures, occurring in ~ 7% and 1% of all cases, respectively.

Pilon fractures can occur from both low- and high-energy mechanisms.

• ○
  

  Low-energy fractures typically occur due to rotational forces imparted to the distal tibia.

  
  
• ○
  

  High-energy fractures are generally due to axial force that drives the talus into the tibial plafond, causing an “implosion” of the articular surface.

In the most severe plafond fracture patterns, the articular segment is fractured into numerous pieces with certain segments driven proximally into the metaphysis, creating marked joint incongruity and associated metaphyseal defects.

An associated fibula fracture is often present in pilon fractures.

The most common fracture pattern occurs with the ankle in dorsiflexion (i.e., the foot on the brake pedal during a motor vehicle accident).

• ○
  

  When the ankle is dorsiflexed at the time of injury, pilon fracture patterns involve the anterior articular surface of the tibial plafond.

Central articular (implosion) injury is the result of an axial load on the foot in neutral position.

A severely traumatized soft tissue envelope accompanies the higher energy pilon fractures.

• ○
  

  Although many pilon fractures are open injuries, closed fractures have significant soft tissue compromise as well.

Initial management of pilon fractures depends as much on the soft tissue as the bony injury.

• ○
  

  Understanding the soft tissue injury accompanying pilon fractures is of utmost importance for providing optimal treatment while minimizing complications.

Classification systems have been developed to stratify both severity of fracture pattern and soft tissue injury.

Although the Arbeitsgemeinschaft für Osteosynthesefragen (AO)/Orthopaedic Trauma Association (OTA) classification system is the most widely accepted fracture classification system, the Ruedi-Allgower system is the classic fracture scheme often known and used for this injury throughout the world.

Ruedi-Allgower type 1 fractures are minimally displaced cleavage fractures, in contrast to type 2 injuries, which are displaced. Type 3 injuries portend the worst prognosis as a consequence of articular comminution and metaphyseal impaction.

Moderate interobserver reliability makes the AO/OTA system reliable for classifying pilon fractures (Swiontkowski et al 1997).

• ○
  

  The distal tibia is designated as #43 (4 = tibia, 3 = distal segment).

  
  
• ○
  

  The fractures are divided into types and further into groups then subgroups.

43C patterns are high-energy injuries with a compromised soft tissue envelope.

• ○
  

  Irreversible damage to the articular cartilage, and at times the soft tissues, occurs at the time of injury.

Soft tissue injury has been standardized using the method of Tscherne for closed fractures and the Gustilo-Anderson classification for open injuries.

• ○
  

  The Tscherne scheme has 4 grades of increasing severity for soft tissue injury in closed fractures.

  
  
  
  
  • –
    

    Tscherne grades 0 and 1 have negligible soft tissue injury and superficial abrasions/contusion, respectively.

    
    
  • –
    

    Type 2 Tscherne injury describes advanced muscle contusion and deep, potentially contaminated abrasions.

    
    
  • –
    

    Pilon fractures with extensive crush, degloving, or vascular injury are considered type 3.

  
  
  
  
• ○
  

  The most widely accepted open fracture classification is credited to Gustilo and Anderson.

  
  
  
  
  • –
    

    Gustilo type 1 open fractures are generally clean with a < 1-cm skin laceration.

    
    
  • –
    

    Type 2 open fractures have more extensive soft tissue injury with minimal to moderate crushing, typically with a laceration > 1 cm.

    
    
  • –
    

    Open pilon fracture with extensive soft tissue injury and a severe crush component are graded as type 3.

    
    
    
    
    • □
      

      Type 3A open fractures have adequate soft tissue coverage over the fracture.

      
      
    • □
      

      Type 3B are usually contaminated with extensive periosteal stripping and bone exposure necessitating flap coverage.

      
      
    • □
      

      Open fractures with vascular injury requiring repair along with extensive soft tissue compromise are considered type 3C.

    
    

  
  

In view of the fact that most pilon fractures usually occur as the result of violent trauma (i.e., motor vehicle accident), associated bodily injuries must be considered in the work-up of these patients.

Examination should document the presence of both closed and open soft tissue injury as well as location and extent of lacerations, abrasions, and contamination.

A systemic motor and sensory examination is warranted in addition to documentation of distal pulses.

Leg compartment syndrome should be diagnosed based on clinical examination and confirmed if necessary with compartment pressures.

Radiographs are critical for characterization of the bony injury and joint position and must include an ankle anteroposterior, mortise, and lateral view.

• ○
  

  Traction views may be valuable for further characterization of the pilon fracture.

Computed tomography (CT) examination is best delayed until restoration of length in shortened fractures because ligamentotaxis helps to better approximate fragments closer to their native position, making interpretation easier.

Initial splinting in the emergency room decreases further soft tissue trauma, and fracture dislocations should be reduced with adequate anesthesia to restore joint alignment.

Open wounds are covered with moist gauze, and antibiotic and tetanus protocols are employed.

Ruedi and Allgower revolutionized the management of pilon fractures after reporting their operative strategy in 1969.

The series reported by Ruedi and Allgower described superior outcomes after formal open reduction and internal fixation (ORIF) in their patient population with few major complications.

The operative principles described by the AO group for operating pilon fractures serves as a working paradigm for ORIF of these injuries.

• ○
  

  Principle 1: Length and rotation is restored by ORIF of the fibula.

  
  
• ○
  

  Principle 2: Anatomical reconstruction of the articular surface of the tibial plafond is performed after the acute phase of the injury.

  
  
• ○
  

  Principle 3: Metaphyseal bone defects are bone grafted to buttress the articular surface.

  
  
• ○
  

  Principle 4: Buttressing of the tibial metaphysis is then required while connecting the articular block to the diaphysis.

These principles (perhaps with #3 optional), restoration of articular surface, realign joint surface to shaft, then bridge metaphyseal comminution with fixation, can be applied to any periarticular fracture.

The results of the classic study from the Swiss AO group could not, however, be reproduced by all surgeons.

• ○
  

  Reports describing ORIF of tibial pilon fractures revealed a concerning complication rate with higher energy pilon fractures, including wound problems, deep infection, nonunion, and malunion (McFerran et al 1992, Teeny and Wiss 1993).

Recognition of a different category of higher energy pilon injuries emerged, which was quite different than those treated by Ruedi and Allgower, who treated lower energy injuries primarily in healthy skiers: So-called “boot top injuries.”

New research was undertaken to determine the best way to manage higher energy fractures of the tibial plafond in response to the higher rates of infection.

External fixation alone became popular for managing complex pilon fractures associated with both closed and open compromised soft tissue envelopes.

• ○
  

  The rate of deep infection decreased with external fixation, however, at a cost.

  
  
• ○
  

  The quality of reduction with external fixation alone was suboptimal, leading to poor outcomes secondary to joint arthrosis.

Initial external fixator constructs spanned the ankle joint until fracture union, resulting in unacceptable ankle stiffness.

Small wire epiphyseal-diaphyseal ring fixators were then employed to treat pilon fractures to allow for early ankle motion in an effort to minimize long-term ankle stiffness.

Limited ORIF to improve articular reductions without formal operative exposures was then employed to supplement external fixation strategies.

Unsatisfied with the limitations of external fixation strategies, including compromised articular reduction, pin tract complications, and patient dissatisfaction, new strategies to allow for ORIF were investigated.

Protocols developed to enhance soft tissue recovery prior to definitive operative fracture fixation, including greater waiting time for such recovery, became the mainstay.

A common modern algorithm is to apply a spanning external fixator to maintain length urgently following injury.

• ○
  

  Once the swelling has peaked and regressed 1-3 weeks after injury, open reduction of the tibia (and fibula) can be performed with removal of the temporary external fixator.

Some surgeons have found that immediate (within a few hours of injury) open reduction, prior to significant swelling, can be performed safely.

• ○
  

  There may be some benefits to this technique with possibly less swelling and stiffness.

  
  
• ○
  

  This is still an emerging technique, and the risk of opening a pilon fracture during the initial stages of swelling could be devastating.