What diagnostic test should I use to investigate a possible biceps or triceps tear?

Diagnostic Testing for Biceps and Triceps Tears

For suspected biceps or triceps tears, ultrasound should be used as the first-line imaging modality due to its high sensitivity (95%), non-invasive nature, and cost-effectiveness, followed by MRI without contrast when ultrasound is inconclusive or surgical intervention is being considered. 1

Diagnostic Algorithm

First-Line Imaging

• Plain radiographs (X-rays)
  • Start with X-rays to rule out associated fractures or bony abnormalities
  • May show hypertrophic bone formation at the radial tuberosity in chronic cases 2

Second-Line Imaging

• Ultrasound
  • Recommended as the primary test for suspected tendon rupture 1
  • High sensitivity (95%) and specificity (71%) for differentiating complete versus partial tears
  • Non-invasive, readily available, and cost-effective
  • Can effectively visualize both complete and partial tears of distal biceps tendons 3

Third-Line Imaging

• MRI without contrast
  • Indicated when:
    • Ultrasound results are inconclusive
    • Surgical intervention is being considered
    • More detailed assessment of associated injuries is needed
  • Superior for definitive assessment and accurate identification of tear type
  • Sensitivity of 76% and specificity of 50% 1
  • Helps differentiate incomplete tears and define tendon degeneration 4

Clinical Examination to Guide Imaging

Before ordering imaging, perform specific physical tests to increase diagnostic accuracy:

• For Distal Biceps Tears:

  • Hook test
  • Passive forearm pronation test
  • Biceps crease interval test
  • Bicipital aponeurosis flex test 5

• General Examination:

  • Look for visible deformity, ecchymosis, and asymmetry compared to unaffected arm
  • Assess strength in elbow flexion, forearm supination, and shoulder flexion
  • Compare findings to the unaffected side 1

Important Considerations

• Early and accurate diagnosis is crucial as complete tears typically require early surgical intervention for optimal outcomes 1
• Delaying appropriate diagnosis and treatment may lead to suboptimal outcomes, especially for complete tears where early surgical reattachment is recommended 1
• For pediatric patients, use the lowest dose protocols for X-rays when needed due to radiation exposure risks 1

Management Based on Diagnostic Findings

• Complete tears: Early surgical reattachment to the radial tuberosity is recommended for optimal functional outcomes 2
• Partial tears: Conservative management may be appropriate, but partial tears >50% may require surgical treatment similar to complete tears 1
• Chronic ruptures: May still benefit from surgical reattachment, though more complex due to tendon retraction and scarring 2

The diagnostic approach should be prompt and systematic, as biceps and triceps tendon injuries can cause significant disability if not properly identified and treated 6.