Preliminary Diagnosis: Acromioclavicular arthritis

I. What imaging technique is first-line for this diagnosis?

  • AP radiographs of the acromioclavicular joint

  • May need additional axillary films (shows posterior dislocation), Zanka (10- to 15-degree cephalad angulation), and/or stress views (10-15 pounds suspended by straps at the wrists)

II. Describe the advantages and disadvantages of this technique for diagnosis of acromioclavicular arthritis.

Advantages
  • Quick


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  • Inexpensive

Disadvantages
  • Difficult to assess for soft tissue injury

III. What are the contraindications for the first-line imaging technique?

  • Relative contraindication includes pregnancy. No absolute contraindications.

IV. What alternative imaging techniques are available?

  • CT of the acromioclavicular joints without contrast

  • MRI of the scromioclavicular joints without contrast.

  • Ultrasound evaluation with high frequency, linear transducer with evaluation using gray-scale imaging and color Doppler

V. Describe the advantages and disadvantages of the alternative techniques for diagnosis of acromioclavicular arthritis.

CT of the acromioclavicular joints without contrast
Advantages
  • Very specific for osseous abnormalities

  • Helpful when patient cannot position in an axillary view, identifies step-offs and subluxation well

  • Relatively quick exam

Disadvantages
  • Exposure to ionizing radiation

  • More expensive than plain films

MRI of the acromioclavicular joints without contrast
Advantages
  • Helpful to assess ligamentous injury, marrow edema, joint effusion, and other associated soft tissue abnormalities

Disadvantages
  • Expensive

  • Requires significant patient cooperation to minimize motion artifact

  • Time consuming

Ultrasound evaluation with high-frequency linear transducer with evaluation using gray-scale imaging and color Doppler
Advantages
  • Inexpensive

  • Dynamic assessment that allows comparison of both AC joints

Disadvantages
  • Quality of assessment depends on sonographer

  • Reproducability depends on a skilled technician

VI. What are the contraindications for the alternative imaging techniques?

CT of the acromioclavicular joints without contrast
  • Relative contraindication includes preganancy

MRI of the acromioclavicular joints without contrast
  • Non-MRI-compatible hardware

Ultrasound evaluation with high-frequency linear transducer with evaluation using gray-scale imaging and color Doppler
  • No significant contraindication