What are the recommended initial x-ray views for a proximal fibula fracture?

Recommended X-ray Views for Proximal Fibula Fracture

For a suspected proximal fibula fracture, obtain standard anteroposterior (AP) and lateral knee radiographs as the initial imaging study. 1

Standard Imaging Protocol

The initial evaluation of proximal fibular fractures requires knee radiographs, not ankle films, since the proximal fibula is part of the knee joint anatomy:

• Minimum two-view series: AP and lateral views of the affected knee are the standard initial imaging modality 1
• Additional patellofemoral view: This third view is typically obtained to complete the knee series, though it is less critical for isolated fibular assessment 1

Clinical Context and Associated Injuries

Proximal fibular fractures rarely occur in isolation and understanding the injury pattern guides appropriate imaging:

• Maisonneuve fractures: Proximal fibular fractures can be associated with ankle injuries (distal syndesmotic disruption or deltoid ligament tears), requiring ankle radiographs in addition to knee films when ankle tenderness or instability is present 2
• Tibial plateau fractures: Proximal fibular fractures frequently accompany tibial plateau fractures, with morphological patterns varying based on the tibial column involvement 3
• High-energy trauma: In significant trauma scenarios (motor vehicle accidents, knee dislocations), standard knee radiographs remain the first imaging study, with clinical judgment superseding any decision rules 1

Important Radiographic Assessment Points

When evaluating proximal fibular fractures on knee radiographs, specific anatomical relationships should be assessed:

• AP view assessment: The fibula should point toward the lateral femoral epicondyle in 94.4% of normal knees, and weight-bearing films significantly affect this relationship 4
• Lateral view assessment: The fibula should point toward the posterior half of Blumensaat's line in 98.1% of normal knees, with knee flexion >20 degrees required for accurate assessment 4
• Tibiofibular overlap: Normal overlap ranges from >0% to <75% on both AP (94.1%) and lateral (84.5%) views, requiring true orthogonal radiographs for accurate measurement 4

Common Pitfalls to Avoid

• Ordering ankle films instead of knee films: The proximal fibula is best visualized on knee radiographs; ankle films will not adequately capture proximal fibular injuries 1
• Failing to obtain orthogonal views: Single-view radiographs miss fractures and displacement patterns that alter treatment decisions 5
• Missing associated injuries: Always examine for concomitant tibial plateau fractures on the same radiographs, as these commonly occur together and significantly impact management 3
• Inadequate positioning: Non-weight-bearing or improperly flexed views can lead to misinterpretation of proximal tibiofibular joint integrity 4

Advanced Imaging Considerations

While not routinely indicated as initial imaging, advanced modalities have specific roles:

• CT knee: Superior to radiographs for fracture detection and classification but not used as the initial study 1
• MRI knee: Reserved for cases with negative radiographs but persistent clinical suspicion, particularly for evaluating occult fractures and associated soft tissue injuries 1