eMedicine Specialties > Orthopedic Surgery > Foot & Ankle

Pilon Fractures

Author: Vinod K Panchbhavi, MD, FRCS, FACS, Associate Professor, Chief, Division of Foot and Ankle Surgery, Department of Orthopedics, University of Texas Medical Branch School of Medicine
Contributor Information and Disclosures

Updated: Jun 19, 2008

Introduction

Pilon fractures in the distal tibia result from axial forces that can range from low to high energy and produce a spectrum of articular and metaphyseal injuries. These can be challenging to manage, especially when associated with significant soft-tissue injury. Although a variety of options are available to treat these fractures, timing of definitive surgery is crucial with respect to the condition of the soft tissues. Despite the advances that have been made in managing these fractures, new developments in the field continue to lead to better outcomes.

History of the Procedure

Pilon is a French word for pestle, an instrument used for crushing or pounding.¹ The first recorded use of the term pilon in the orthopedic literature is in 1911, by Étienne Destot.² In 1959, Jergesen stated that open reduction and stabilization of severe tibial pilon fractures is impossible.

The treatment of pilon fractures has evolved over the last century. Conservative management gave way to surgical intervention when implants became available, but poor outcomes led to a return to cast immobilization or limited internal fixation of the fibula only. However, outcomes after nonoperative treatment continue to be poor.

In the early 1960s, the Association for Osteosynthesis/Orthopaedic Trauma Association (AO/OTA) developed general guidelines for the treatment of intra-articular distal tibial fractures, which led to open reduction and anatomic and rigid internal fixation.

Good outcomes were reported when these principles were used for low-energy injuries (eg, those from skiing accidents). However, when the same principles were used to fix high-energy injuries (eg, from motor vehicle accidents), the outcomes were poor, mainly because of soft-tissue complications.

Over the years, the importance of soft tissues and the differences between low- and high-impact energy injuries have become better understood. This has led to the development of newer treatment concepts, which continue to evolve, along with an availability of more advanced surgical options, such as minimally invasive internal fixation implants.^3,4,5

Problem

Pilon fractures involve the dome of the distal tibial articular surface and extend into the adjacent metaphysis. The fibula may or may not be intact (see Images 1-6).

Frequency

Pilon fractures account for approximately 7% of tibial fractures.

Etiology

Pilon fractures occur when the talus is driven vertically into the tibial plafond. The cortical bone shatters; the softer metaphyseal bone can also be affected.

Pathophysiology

Depending on the mechanism, a wide variety of injuries can occur. At one end of the spectrum are low-energy injuries that follow activities such as skiing and result in minimal soft-tissue injury. The fracture fragments are fewer, may have a spiral orientation, and are relatively minimally displaced.

At the other end of the spectrum are high-energy injuries such as a fall from height or a high-speed motor vehicle accident. Such a mechanism can produce significant comminution with multiple displaced fracture fragments and, importantly, a contused or crushed soft-tissue envelope, which could also be breached and open to external contamination through wounds. The fibula is usually fractured in high-energy injuries.

A variable amount of damage can occur to the articular cartilage of the tibia, which can be scuffed, bruised, or fragmented. In severe cases, the weight-bearing central dome can be fragmented. The fragments, which can be tiny (approximately 2-3 mm³), are completely broken off and are driven up into the metaphysis of the tibia by the impact. Damage to the talar articular surface can also occur.

Presentation

Patients involved in high-energy trauma should be treated according to advanced trauma life-support guidelines because they may have associated life- or limb-threatening injuries.

History

Obtain a history of any allergies, intake of medications, past medical history (eg, diabetes mellitus, peripheral vascular or naturopathic disease), and events leading to the injury. An understanding of the mechanism of injury may lead to an indication of the forces involved. Also, knowledge of any history of previous trauma in either limb is helpful during restoration.

Clinical presentation varies depending on the severity of the injury and the duration from the time of the injury. Soft tissues swell rapidly, and tissue tension can produce enormous blisters. The underlying bony fragments may be significantly displaced, threatening the viability of the overlying soft-tissue envelope. Crushing, degloving, bruising, and hematomas can further compromise soft tissues (see Image 7).

The Oestern and Tscherne classification of soft-tissue injury in closed fractures is as follows:

• Grade 0 - Minimal soft-tissue damage, indirect injury to limb (torsion), simple fracture pattern
• Grade 1 - Superficial abrasion or contusion, mild fracture pattern
• Grade 2 - Deep abrasion with skin or muscle contusion, severe fracture pattern, direct trauma to limb
• Grade 3 - Extensive skin contusion or crush injury, severe damage to underlying muscle, subcutaneous avulsion, compartment syndrome

Traumatic wounds can vary from a puncture wound, which is usually either medial or lateral, to large injuries with extensive loss of soft tissue.

The Oestern and Tscherne classification for open fractures uses wound size, level of contamination, and fracture pattern to grade open fractures, and is as follows:

• Grade I - Open fractures with a small puncture wound without skin contusion, negligible bacterial contamination, and a low-energy fracture pattern
• Grade II - Open injuries with small skin and soft-tissue contusions, moderate contamination, and variable fracture patterns
• Grade III - Open fractures with heavy contamination, extensive soft-tissue damage, and, often, associated arterial or neural injuries
• Grade IV - Open fractures with incomplete or complete amputations

The Gustilo classification can also be used for open fractures and is as follows:

• Grade 1 - Skin lesion smaller than 1 cm; clean, simple bone fracture with minimal comminution
• Grade 2 - Skin lesion larger than 1 cm, no extensive soft-tissue damage, minimal crushing, moderate comminution and contamination
• Grade 3 - Extensive skin damage with muscle and neurovascular involvement, high-speed injury, comminution of the fracture, instability
  • Grade 3a - Extensive laceration of soft tissues with bone fragments covered, usually high-speed traumas with severe comminution or segmental fractures
  • Grade 3b - Extensive lesion of soft tissues with periosteal stripping, contamination, and severe comminution due to high-speed traumas; usually requires replacement of exposed bone with a local or free flap as a cover
  • Grade 3c - Exposed fracture with arterial damage that requires repair

Any neurovascular injury must be documented at the time of presentation. Compartment syndrome is a risk in acute injuries; therefore, frequent evaluations are necessary. A systematic and complete evaluation is necessary because other injuries (eg, to the spine or other extremities) may have occurred after a fall from height.

Clinical types

Based on the mechanism of injury and damage to soft tissue and bone, pilon fractures can be divided into 2 broad categories as follows:

• Low-impact pilon fractures
  • Mechanism - Low-energy rotational force and some axial compression
  • Soft tissue - Little soft-tissue injury
  • Bone - Little articular comminution
• High-impact pilon fractures
  • Mechanism - High-energy axial compression
  • Soft tissue - Extensive soft-tissue injury
  • Bone - Severe articular and metaphyseal comminution

Indications

Indications for surgery include the following:

• Open fracture
• Displaced fracture
  • Articular fragments with a gap of more than 2 mm or step of more than 1 mm
  • Rotational malalignment
• Vascular compromise
• Compartment syndrome

Relevant Anatomy

The distal tibia and fibula, along with the ligaments and capsule, help to form the ankle mortise. Any disruption of length, axis, or rotation of the fibula or the tibia can result in an incongruent ankle joint.

The lateral aspect of the distal tibia forms a triangular notch, which is where the fibula articulates. The interosseous and the anterior and posterior tibiofibular ligaments bind these bones together.

The ligaments often avulse fragments from the tibia, such as the anterolateral fragment termed the Chaput fragment and the posterior malleolar fragment termed the Wagstaffe fragment.

The blood supply in the distal leg is provided by branches that arise from the posterior tibial, peroneal, and dorsalis pedis arteries.

The great saphenous vein travels along with the saphenous nerve anterior to the medial malleolus. The small saphenous vein passes posterior to the lateral malleolus. Disruption of the venous system can lead to subsequent chronic venous stasis.

Contraindications

The presence of soft-tissue swelling and/or blisters, peripheral vascular disease, and/or wound infection are contraindications for extensive surgery such as open reduction and internal fixation. External fixation with use of a hybrid frame or a cast can be used in such situations.

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