What diagnostic test should be ordered for an olecranon lesion?

Diagnostic Testing for Olecranon Lesions

Plain radiographs (anteroposterior and lateral views) are the mandatory first-line imaging study for any suspected olecranon lesion, as they effectively exclude fractures, dislocations, and bony abnormalities while guiding all subsequent management decisions. 1, 2

Initial Imaging Approach

• Standard radiographs are sufficient to confirm the diagnosis in the vast majority of olecranon injuries, including the 10% of upper limb fractures that involve this region 2
• The American College of Radiology explicitly recommends plain radiographs as the initial imaging modality to exclude fractures, dislocations, or other bony abnormalities in all elbow pathology 1
• Radiographs can also detect heterotopic ossification and soft-tissue calcifications that may be associated with olecranon pathology 1

When Initial Radiographs Are Normal or Equivocal

If clinical suspicion remains high despite normal initial radiographs, repeat radiographs in 10-14 days can detect delayed fracture visibility through early callus formation. 3

Advanced Imaging Options:

• MRI without contrast is the preferred next study when radiographs are normal but an occult fracture or osteochondral lesion is suspected, as it demonstrates bone marrow edema, periosteal fluid, and associated soft-tissue injuries 4
• MRI is as sensitive as 3-phase bone scan for detecting stress fractures while providing superior soft-tissue detail 4
• CT imaging should be reserved for cases requiring detailed assessment of complex fracture patterns, displacement, comminution, or intra-articular extension after a fracture is already identified on radiographs 4
• CT can identify occult fractures in 12.8% of cases with positive elbow extension test when radiographs remain normal 3

Imaging Modalities to Avoid

• Do not order CT, bone scan, or contrast-enhanced studies for routine olecranon bursal pathology, as these have no established role 1
• 3-phase bone scan has limited utility as a first-line test, though it can detect stress fractures with high sensitivity 4
• Ultrasound has limited value for olecranon lesions due to acoustic shadowing from bone, though it can demonstrate bursal thickening in chronic bursitis 1, 5

Clinical Decision Algorithm

Step 1: Order AP and lateral radiographs immediately

• These identify 90% of clinically significant olecranon pathology 2
• Look specifically for fracture lines, joint effusions, and soft-tissue swelling 4

Step 2: If radiographs show a fracture

• No additional imaging is needed for simple undisplaced fractures 2
• Consider CT only for complex, comminuted, or intra-articular fractures requiring surgical planning 4

Step 3: If radiographs are normal but clinical suspicion persists

• Repeat radiographs in 10-14 days for suspected occult fracture 3
• Order MRI without contrast if immediate diagnosis is needed or if osteochondral lesion is suspected 4
• Consider CT only if MRI is contraindicated and clinical suspicion remains very high 3

Common Pitfalls to Avoid

• The lateral elbow radiograph alone is insufficient for assessing intra-articular olecranon reduction—trauma surgeons correctly identify malreductions only 73% of the time on lateral views alone 6
• Do not skip radiographs and proceed directly to advanced imaging; this violates established ACR guidelines and increases costs without improving outcomes 1
• Avoid ordering MRI arthrography for olecranon lesions, as there is limited evidence supporting its use over standard MRI 4
• Remember that full elbow extension has a negative predictive value of 98.4% for fracture in adults, but olecranon fractures are the critical exception—these patients may still extend their elbow despite fracture 7