AAOS Comprehensive Orthopaedic Review 4: Print + Ebook (AAOS - American Academy of Orthopaedic Surgeons)

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72 | Imaging of the Shoulder and Elbow

7. Inflammatory arthropathy 8. Symptomatic plica

D. Ultrasonography 1. Ultrasonography continues to be used more fre quently for the evaluation of tendon and ligament disorders around the elbow. 2. Indications a. Can be used to assess both acute and chronic distal biceps and triceps tendon injuries b. Has been described as an accurate tool for assessment of medial ulnar collateral ligament injuries in throwing athletes. Stress ultraso nography can also be useful to assess medial joint laxity. c. Has demonstrated good accuracy in evalua tion of both lateral and medial epicondylitis d. Image-guided injections or procedures

6 | Shoulder and Elbow

Figure 10 Sagittal T2-weighted magnetic resonance image shows a complete distal biceps tear with retraction (arrow).

KEY LEARNING POINTS

1. The axillary view helps detect an occult, locked posterior shoulder dislocation in a patient who exhibits a lack of passive external rotation. 2. A true AP view of the shoulder shows the anterior greater tuberosity in profile. 3. The normal acromiohumeral distance is 7 to 14 mm. 4. The normal coracoclavicular distance is 1.1 to 1.3 cm. 5. CT with three-dimensional reconstruction is indicated for assessment of glenoid bone loss in shoulder insta bility as well as glenoid morphology and version in shoulder arthritis. 6. MRI with intra-articular gadolinium is the study of choice to detect labral pathology. 7. MRI is the modality of choice to detect a spinoglenoid cyst. 8. Ultrasonography is a convenient, noninvasive, cost-effective, and accurate test for the evaluation of rota tor cuff disease. Limitations of ultrasonography include its inability to assess intra-articular pathology and its dependence on an experienced technician. Ultrasonography and MRI have been shown to be equally accurate in assessing full-thickness rotator cuff defects. Ultrasonography has become a modality of choice for evaluating patients in the postoperative period following rotator cuff repair or shoulder arthroplasty. 9. Magnetic resonance arthrography of the elbow is the most accurate test to detect ulnar collateral ligament tears. 10. The anterior fat pad sign on a lateral elbow radiograph is suspicious for possible occult elbow fracture. Copyright © Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. 2023

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AAOS Comprehensive Orthopaedic Review 4