What x-ray view should be ordered to assess for a left ischial tuberosity fracture?

Radiographic Assessment for Left Ischial Tuberosity Fracture

For suspected left ischial tuberosity fracture, an anteroposterior (AP) pelvis X-ray should be ordered as the initial imaging study, followed by additional specialized views as needed based on initial findings. 1, 2

Initial Imaging Approach

Primary View:

• Anteroposterior (AP) pelvis X-ray
  • Provides comprehensive visualization of the entire pelvic ring including both ischial tuberosities
  • Allows comparison between sides to detect asymmetry or displacement 2
  • Considered the standard first-line imaging for pelvic trauma and suspected fractures 1

Additional Views (if needed based on initial AP findings):

• Lateral view of the hip/pelvis

  • Helps evaluate displacement in the sagittal plane
  • Particularly useful for assessing fragment displacement in avulsion injuries 1

• Axial view

  • May be necessary for better visualization of the ischial tuberosity 1

Clinical Considerations

When to Consider Advanced Imaging:

• If radiographs are negative but clinical suspicion remains high
• For assessment of:
  • Fracture displacement (>15mm displacement may require surgical intervention) 3
  • Non-union in chronic cases
  • Associated soft tissue injuries

Advanced Imaging Options:

1. CT scan

   • Superior for detecting and characterizing fracture patterns
   • Gold standard for identifying pelvic fractures with reported sensitivity of 94-100% 1
   • Particularly valuable for complex fractures or when planning surgical intervention

2. MRI

   • Consider when soft tissue injuries are suspected
   • Useful for evaluating associated hamstring tendon involvement
   • Better for detecting stress fractures that may not be visible on plain radiographs 4

Special Considerations

• In adolescent patients, be aware of the ossification pattern of the ischial tuberosity apophysis which can affect fracture appearance 5
• Avulsion fractures of the ischial tuberosity are most common in adolescent athletes, particularly those involved in sports requiring kicking or sudden hamstring contraction 6
• Displacement >15mm may be an indication for surgical intervention rather than conservative management 3

Common Pitfalls to Avoid

• Failing to obtain a complete pelvis view (rather than just hip views) when evaluating ischial tuberosity injuries 2
• Misinterpreting normal apophyseal growth plates in adolescents as fractures
• Ordering advanced imaging before appropriate radiographs have been obtained 2
• Missing bilateral injuries - ensure comparison with the contralateral side 4

By following this imaging approach, clinicians can effectively diagnose ischial tuberosity fractures and determine appropriate management to improve patient outcomes and reduce complications.