Lecture Notes: Acetabulum Fractures Classification and Radiographic Workup

Radiographic Workup for Acetabulum Fractures

• **Imaging Types:
  • AP X-ray
  • Judet Views
  • CT Scans
  • 3D CT Scans
  • Dynamic Stress Views (when necessary)

Classification of Acetabulum Fractures

• **Main Classification System: Letournel and Judet
  • Adopted by the Orthopedic Trauma Association
  • Two Types: Elementary and Associated

Elementary Patterns

• Involves part or all of one column (except one type)
  • **Types:
    • Posterior Wall Fractures
    • Anterior Wall Fractures
    • Posterior Column Fractures
    • Anterior Column Fractures
    • Transverse Fractures (included for its purity)
• **Key Points:
  • Representative examples shown in an inverted Y schematic
  • Variants exist; fractures don’t always look exactly like the examples

Associated Patterns

• Involves at least two elementary forms
  • **Types:
    • Posterior Column and Posterior Wall
    • Transverse and Posterior Wall
    • T-shaped Fractures
    • Anterior with Posterior Hemitransverse
    • Associated Both-Column Fractures
• **Key Points:
  • Posterior Column and Wall: typically treated posteriorly
  • Transverse with Posterior Wall: requires posterior approach
  • T-shaped: may need anterior, posterior, or combined approach
  • Associated Both-Column: equivalent to a type C periarticular fracture

Roof Arc Measurements

• **Purpose:
  • Determine if the remaining intact acetabulum can maintain stable congruent relationship with femoral head
  • Measured on AP, Obturator Oblique, and Iliac Oblique views
• **Key Points:
  • Not applied to both-column fractures or isolated posterior wall fractures
  • Numbers and angles important for test purposes

Common Fracture Types and Characteristics

Posterior Wall Fractures

• **Characteristics:
  • Separation of posterior articular surface
  • Often seen with posterior femoral head dislocation
  • Subtypes: below roof, involving roof, involving subchondral groove, marginal impaction
• **Imaging:
  • AP X-ray: disruption of posterior rim
  • Judet Views: better visualization
• **Treatment Considerations:
  • Marginal Impaction: requires surgical reduction

Posterior Column Fractures

• **Characteristics:
  • Disruption of ischium
  • Medial displacement of femoral head
• **Imaging:
  • Judet Views: show intact anterocolumn, displaced posterior column

Anterior Wall Fractures

• **Characteristics:
  • Disruption of small portion of anterior roof
  • Often involves quadrilateral plate
• **Imaging:
  • Judet Views: show disrupted anterocolumn, intact posterior column

Anterior Column Fractures

• **Characteristics:
  • Variants: low, intermediate, high (involving iliac wing)
• **Imaging:
  • AP Radiograph: disrupted iliopubic line
  • Judet Views: show extent of displacement

Transverse Fractures

• **Characteristics:
  • Involves both anterior and posterior columns
  • Subtypes: transtectal, juxtatectal, infratectal
• **Imaging:
  • AP Radiograph: disrupted lines
  • Judet Views: show fracture orientation
  • CT Scan: helpful to confirm fracture pattern and avoid misinterpretation

Summary

• Understanding of elementary and associated fracture types essential for proper classification and treatment
• Importance of thorough imaging for accurate diagnosis and treatment planning
• Next lecture will cover associated fracture types in detail