CT Scan for Patella Fracture with Poor X-rays
CT scanning is beneficial for evaluating patella fractures when X-rays are poor quality, as it provides superior detection and classification of fracture patterns that may be missed on plain radiographs. 1
Imaging Algorithm for Patella Fractures
Initial Assessment
- Standard radiographs (AP and lateral views) are the first-line imaging modality for suspected patella fractures
- When radiographs are poor quality or inconclusive but clinical suspicion remains high, advanced imaging is warranted
Benefits of CT for Patella Fractures
- CT demonstrates superior sensitivity (80-100%) compared to plain radiographs for fracture detection 2
- CT provides excellent visualization of:
- Fracture comminution
- Articular surface involvement
- Fragment displacement
- Occult fracture lines not visible on radiographs
Evidence Supporting CT Use
- According to the ACR Appropriateness Criteria, CT is superior to knee radiographs in detection and classification of fractures 1
- Research shows that CT scanning leads to changes in:
- Fracture classification in 66% of cases
- Treatment planning in 49% of cases 3
- CT frequently reveals distinctive distal pole fracture patterns that are unappreciated on plain radiographs in 44% of cases 3
When to Consider MRI Instead
- MRI is preferred when:
- Soft tissue injuries are the primary concern
- Ligamentous or meniscal damage is suspected
- Bone marrow contusions need evaluation
- MRI has near 100% sensitivity for fracture detection and excellent capability for detecting bone marrow contusions and occult fractures 2
Clinical Implications of CT Findings
- Understanding the precise fracture pattern is fundamental in choosing the appropriate fixation construct 3
- CT findings may reveal:
- Need for different surgical approach
- Alternative fixation methods
- Previously undetected comminution requiring more complex repair
Potential Pitfalls
- Radiation exposure is higher with CT compared to plain radiographs
- CT may not fully evaluate associated soft tissue injuries
- Vertical patellar fractures may still be challenging to visualize and are best evaluated with sunrise or Merchant views on radiographs 4
- Osteochondral fractures of the patella may require both CT and MRI for complete evaluation 5
By using CT when X-rays are poor quality, clinicians can better characterize patella fractures, which directly impacts treatment decisions and ultimately patient outcomes in terms of knee function, pain, and mobility.