Abstract
Purpose: To determine the prevalence of abnormal findings at sonography of the shoulder joint in asymptomatic subjects.
Methods: The study group consisted of 70 consecutive subjects, asymptomatic for either shoulder. A musculoskeletal sonographer carried out the ultrasound of a randomly chosen shoulder of the patient in accordance with a specified protocol that comprised imaging of the rotator cuff tendons, tendon of the long head of the biceps brachii muscle, subacromial-subdeltoid bursa, acromioclavicular joint, and posterior labrum. The scans were then retrospectively evaluated by three expert musculoskeletal radiologists in accord, and abnormal findings were documented. Miniscule or equivocal findings of tendinosis, bursal prominence, and osteoarthritis were omitted.
Results: A total of 37 right and 33 left shoulders were imaged in 70 subjects, of which 40 were males and 30 were females with a male: female ratio of 1:3. The mean age of the subjects was 45 years, with an age range of 30-70 years. Ultrasound revealed subacromial-subdeltoid bursal thickening in 70% (49/70) of the individuals, acromioclavicular joint arthritis in 60% (42/70), supraspinatus tendinosis in 40% (28/70), subscapularis tendinosis in 27.1% (19/70), partial-thickness bursal surface supraspinatus tear in 15.7% (11/70), partial-thickness tear of the subscapularis tendon in 10% (7/70) and posterior glenoid labral abnormality in 10% (7/70). The rest of the findings had a prevalence of less than 10%.
Conclusion: Asymptomatic abnormalities of the shoulder joint were detected in 86% of the subjects, the most prevalent being subacromial-subdeltoid bursal thickening, acromioclavicular joint osteoarthritis, and supraspinatus tendinosis. Our findings in the asymptomatic population advocate that ultrasound findings should be elucidated carefully with clinical information to detect the cause of the patient's symptoms.

Key words: shoulder, asymptomatic abnormalities, ultrasound, rotator cuff, tear