A 42-Year-Old Male with Ankle Swelling and Pain, Pilon Fracture

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 Pilon fracture

A pilon fracture (also known as a tibial plafond fracture) is a complex and often severe injury involving the distal end of the tibia, typically extending into the weight-bearing surface of the ankle joint.

1. Cause

A pilon fracture is typically caused by high-energy axial loading, such as:

  • Motor vehicle collisions
  • Falls from significant heights (landing on feet)
  • Industrial accidents

Low-energy mechanisms (e.g., simple ankle twists) can also cause pilon fractures in osteoporotic or elderly patients, but are less common.

2. Etiology

The etiology is directly related to axial compressive forces that drive the talus into the distal tibial articular surface, causing:

  • Comminution of the tibial plafond
  • Disruption of the metaphysis and joint congruity
  • Soft tissue damage, including skin, ligaments, and muscles

The mechanism of injury is crucial in determining the severity:

  • Axial load + valgus/varus rotation → complex fracture patterns
  • Pure axial load → vertical split and articular depression

3. Pathophysiology

The pathophysiological process involves:

  • Impaction and compression of the distal tibia by the talus
  • Fracture propagation through the articular surface into the metaphysis
  • Often associated with:
    • Fibular fractures (~75-90% of cases)
    • Soft tissue injury (skin necrosis, compartment syndrome)
    • Articular cartilage damage, predisposing to post-traumatic arthritis

Damage can be classified based on AO/OTA or Rüedi and Allgöwer classification:

  • Type I: non-displaced
  • Type II: displaced with minimal comminution
  • Type III: displaced and highly comminuted

4. Epidemiology

  • Incidence: ~1% of all lower extremity fractures; 5-10% of tibial fractures
  • Sex: Slight male predominance due to higher exposure to trauma
  • Age: Most commonly affects individuals aged 35–50 years
  • Bimodal distribution:
    • High-energy trauma in younger adults
    • Low-energy falls in elderly patients with osteoporosis

5. Clinical Presentation

  • Severe ankle pain and swelling
  • Inability to bear weight
  • Visible deformity of the ankle
  • Crepitus or abnormal motion on palpation
  • Skin changes: blistering, open wounds, tenting
  • High suspicion for:
    • Open fracture
    • Compartment syndrome
    • Neurovascular compromise

6. Imaging Features

Initial imaging:

  • Plain radiographs: AP, lateral, and mortise views
    • Shows fracture lines, displacement, comminution, and joint involvement

Advanced imaging:

  • CT scan (gold standard):
    • Defines articular surface anatomy
    • Assists in preoperative planning
    • Evaluates metaphyseal impaction and comminution

MRI: Rarely used; may be helpful to assess soft tissue and ligamentous injuries, but not routinely required.


 

7. Treatment

Initial management:

  • Reduction and splinting to restore alignment and relieve soft tissue tension
  • Neurovascular assessment
  • Analgesia
  • Elevation and ice
  • Antibiotics for the open fracture

Definitive management:

  • Depends on the fracture pattern, soft tissue condition, and patient status

Surgical Options:

  • External fixation (initial damage control)
  • ORIF (Open Reduction Internal Fixation):
    • Ideal when soft tissues are stable (~7-14 days post-injury)
    • Goals: restore articular surface, alignment, and joint congruity
  • Minimally invasive plating in select cases
  • Arthrodesis (ankle fusion) in severe or non-reconstructible cases

Non-operative management:

  • Rarely indicated, reserved for:
    • Non-ambulatory patients
    • Minimally displaced fractures
    • Significant surgical risk

8. Prognosis

Prognosis depends on:

  • Fracture severity (e.g., Rüedi-Allgöwer type III, AO C3 worse)
  • Accuracy of reduction
  • Soft tissue injury extent
  • Postoperative complications

Common complications:

  • Post-traumatic arthritis (very common)
  • Malunion / Nonunion
  • Wound dehiscence or infection
  • Compartment syndrome
  • Chronic pain and stiffness

Long-term outcomes:

  • Full recovery may take 12–18 months
  • Many patients develop chronic pain and limited range of motion
  • A significant percentage require secondary procedures, including ankle arthrodesis or arthroplasty
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Case Study: 42-Year-Old Male with Ankle Swelling and Pain 
Pilon Fracture

History and Imaging

  1. A 42-year-old male presented with swelling and pain in his right ankle after falling down a flight of stairs.

  2. Ankle radiographs were obtained.

Quiz 1

1. Which of the following findings is NOT present on the radiograph?

(1) A distal fibular fracture
(2) Soft-tissue swelling
(3) A distal tibial fracture
(4) Depression of the tibial plafond

Explanation: The distal fibula appears intact and is best visualized on the oblique view. All other findings are present on the radiograph.

2. What additional imaging study should be obtained?

(1) CT
(2) MRI
(3) No further imaging is necessary

Explanation: A CT scan should be obtained for preoperative planning. MRI is not appropriate in the acute trauma setting, especially when surgery is being considered.

Follow-up CT Imaging

A CT scan was performed for further evaluation.

Quiz 2

1. Which additional finding is revealed on CT?

(1) Posterior tibial tendon entrapment
(2) Distal fibular fracture
(3) Superior peroneal retinacular avulsion
(4) Syndesmosis rupture

Explanation: The only definitive additional finding is entrapment of the posterior tibial tendon between the medial and posterolateral fracture fragments. The distal fibula remains intact. There is no Fleck sign, which would suggest avulsion of the superior peroneal retinaculum. The tibia and fibula remain congruent, indicating that the syndesmosis is intact.

2. What type of fracture is this?

(1) Pilon fracture
(2) Trimalleolar fracture
(3) Tibial shaft fracture
(4) Volkmann fracture

Explanation: Although the tibial shaft is involved, the fracture extends into the articular surface, which characterizes it as a pilon fracture. A trimalleolar fracture involves the medial, lateral, and posterior malleoli only, without significant articular impaction. A Volkmann fracture refers specifically to a fracture of the posterior malleolus.

3. This fracture type is typically caused by high-energy axial loading injuries.

(1) True
(2) False

Explanation: Pilon fractures usually occur when the talus is driven into the distal tibial plafond, typically resulting from high-energy axial loading mechanisms such as falls from height or motor vehicle accidents.

Findings and Diagnosis

Radiographic Findings:
Initial radiographs demonstrate a distal tibial pilon fracture with mild displacement of fracture fragments and posterior displacement of the posterolateral component. The fracture line extends proximally into the mid-diaphysis of the tibia without displacement. Associated soft tissue swelling is also present.

CT Findings:
CT imaging reveals a pilon fracture composed of three primary fragments—anterolateral, medial, and posterolateral—clearly delineated on axial views. The plafond fragments are mildly displaced, with approximately 1 cm of articular depression. The posterior tibial tendon is interposed between the medial and posterolateral fragments. A non-displaced spiral fracture component extends proximally into the mid-diaphysis of the tibia. Surrounding soft tissue swelling is present. Both the fibula and talus remain intact.

Differential Diagnosis:

  • Pilon fracture

  • Trimalleolar fracture

  • Tibial shaft fracture

Final Diagnosis:
Pilon fracture

Discussion: Pilon Fracture

Pathophysiology
A pilon fracture typically results from high-energy axial loading injuries, such as motor vehicle collisions or falls from a significant height. The mechanism involves impaction of the talus into the tibial plafond. Low-energy rotational mechanisms may also cause pilon fractures, but these are less common.

Epidemiology
Pilon fractures most commonly occur in males between the ages of 30 and 50 and account for approximately 5–7% of all tibial fractures.

Clinical Presentation
Patients usually present with acute ankle pain and swelling following axial loading trauma. Open fractures and soft tissue compromise are common in high-energy cases.

Imaging Features
Pilon fractures appear on radiographs as distal tibial fractures extending into the articular surface (tibial plafond). CT is essential for preoperative planning and allows visualization of three principal fracture fragments: anterolateral, medial, and posterolateral. Articular depression and comminution are frequently present. CT may also reveal soft tissue complications such as tendon entrapment, which are not visible on plain radiographs.

Treatment
Pilon fractures are usually treated with a staged surgical approach. Initial management involves external fixation to stabilize the fracture and allow the soft tissues to recover. Definitive open reduction and internal fixation (ORIF) is typically delayed for 10 to 14 days, until the swelling has adequately subsided.

References

  1. Sirkin MS, Sanders RW, DiPasquale TG, Herscovici D Jr. A staged protocol for soft tissue management in the treatment of complex pilon fractures. J Orthop Trauma. 2004;18(8 Suppl):S32–S38.

  2. Pollak AN, McCarthy ML, Bess RS, et al. Outcomes after treatment of high-energy tibial plafond fractures. J Bone Joint Surg Am. 2003;85(10):1893–1900.

  3. Barei DP, Bellabarba C, Sangeorzan BJ, Nork SE. Fractures of the distal tibia treated with intramedullary nails and locking plates: a comparative study. J Orthop Trauma. 2006;20(8):562–566.

  4. Bhandari M, Guyatt GH, Swiontkowski MF, et al. Treatment of open fractures of the shaft of the tibia: a systematic overview and meta-analysis. J Bone Joint Surg Br. 2001;83(1):62–68.

  5. Teeny SM, Wiss DA. Open reduction and internal fixation of tibial plafond fractures. Variables contributing to poor results and complications. Clin Orthop Relat Res. 1993;(292):108–117.

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