The purpose of this study was to examine the range and prevalence of asymp tomatic findings at sonography of the shoulder.
The study sample comprised 51 consecutively enrolled subjects who had no symptoms in either shoulder. Ultrasound of one shoulder per patient was performed by a musculoskeletal sonographer according to a defined protocol that included imaging of the rotator cuff, tendon of the long head of the biceps brachii muscle, subacromial-subdeltoid bursa, acromioclavicular joint, and posterior labrum. The shoulder imaged was determined at random. The 51 scans were retrospectively analyzed by three fellowship-trained musculoskeletal radiologists in consensus, and pathologic findings were recorded. Subtle or questionable findings of mild tendinosis, bursal prominence, and mild osteoarthritis were not recorded.
Twenty-five right and 26 left shoulders were imaged. The subject age range was 40-70 years. Ultrasound showed subacromial-subdeltoid bursal thickening in 78% (40/51) of the subjects, acromioclavicular joint osteoarthritis in 65% (33/51), supraspinatus tendinosis in 39% (20/51), subscapularis tendinosis in 25% (13/51), partial-thickness tear of the bursal side of the supraspinatus tendon in 22% (11/51), and posterior glenoid labral abnormality in 14% (7/51). All other findings had a prevalence of 10% or less.
Asymptomatic shoulder abnormalities were found in 96% of the subjects. The most common were subacromial-subdeltoid bursal thickening, acromioclavicular joint osteoarthritis, and supraspinatus tendinosis. Ultrasound findings should be interpreted closely with clinical findings to determine the cause of symptoms.