What are the initial imaging recommendations for elbow injuries?

Initial Imaging Recommendations for Elbow Injuries

Radiographs should be the initial imaging modality for all acute elbow injuries, with advanced imaging (CT, MRI, or ultrasound) reserved for specific clinical scenarios when radiographs are normal or indeterminate. 1, 2

Initial Evaluation: Radiography

• Standard radiographs should include:

  • Anteroposterior (AP) view
  • Lateral view
  • Additional oblique views as needed

• Key findings on radiographs:

  • Fractures (radial head/neck fractures account for 50% of elbow fractures in adults) 1
  • Dislocations
  • Joint effusion (indicated by posterior and anterior fat pad elevation)
  • Avulsion fractures at tendon/ligament attachment sites
  • Intra-articular bodies
  • Heterotopic ossification
  • Soft tissue calcification 1

• Important radiographic signs:

  • Presence of joint effusion with acute trauma suggests occult fracture
  • Coronoid process fractures indicate prior elbow dislocation and should prompt assessment for associated soft tissue injuries 1

Secondary Imaging for Suspected Fractures (When Radiographs Normal/Indeterminate)

When fracture is suspected but radiographs are normal or indeterminate:

CT Without Contrast

• Indicated for:

  • Suspected occult fractures with positive elbow extension test
  • Need for fracture characterization (size, displacement, angulation)
  • Surgical planning for complex fractures 1, 3

• Benefits of CT:

  • Detects occult fractures in 12.8% of patients with normal radiographs and positive elbow extension test 3
  • Superior visualization of radial head, olecranon, and coronoid process fractures
  • Better characterization of fracture morphology for surgical planning 1

Elbow Extension Test

• Perform when radiographs are normal but fracture is still suspected
• Technique: Patient attempts to fully extend elbow while sitting with shoulders at 90° flexion
• Positive test (inability to fully extend) warrants CT evaluation 3

Secondary Imaging for Suspected Soft Tissue Injuries

When tendon, ligament, or muscle injury is suspected with normal radiographs:

MRI Without Contrast

• Indicated for:

  • Suspected ligament injuries (especially collateral ligaments)
  • Tendon injuries (biceps, triceps)
  • Muscle tears
  • Osteochondral lesions 1, 2, 4

• Benefits of MRI:

  • Superior soft tissue visualization
  • Assessment of ligament integrity
  • Evaluation of tendon pathology
  • Detection of radiographically occult osteochondral injuries 4, 5

Imaging Algorithm for Elbow Injuries

1. All elbow injuries: Initial radiographs (AP and lateral views)

2. If radiographs show fracture/dislocation:

   • Treat according to findings

3. If radiographs normal but fracture suspected:

   • Perform elbow extension test
   • If positive → CT without contrast

4. If radiographs normal but soft tissue injury suspected:

   • MRI without contrast for:
     • Suspected ligament injuries
     • Tendon pathology
     • Osteochondral lesions 1, 2, 6

Common Pitfalls to Avoid

• Failing to recognize fat pad signs on radiographs, which may indicate occult fracture
• Missing coronoid process fractures, which often indicate associated soft tissue injuries
• Overlooking subtle radial head fractures, which account for 50% of elbow fractures
• Not performing CT when elbow extension test is positive despite normal radiographs
• Delaying appropriate imaging for suspected ligament injuries, which can lead to chronic instability 1, 6

By following this evidence-based approach to elbow injury imaging, clinicians can optimize diagnosis, reduce unnecessary imaging, and improve patient outcomes through appropriate early intervention.