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The natural history of asymptomatic rotator cuff tears: a three-year follow-up of fifty cases.

BACKGROUND
Little is known about the clinical and anatomic progression of asymptomatic rotator cuff tears. The purpose of our study was to assess if deterioration in rotator cuff tear anatomy would be correlated to the development of symptoms.


METHODS
Fifty patients with initially asymptomatic full-thickness rotator cuff tears were followed clinically, sonographically, and by magnetic resonance imaging over three years. Changes of tear size, muscle atrophy, fatty degeneration, and condition of the long head of the biceps tendon were compared between tears that developed symptoms and those that did not.


RESULTS
Eighteen of fifty tears developed symptoms during follow-up. There was a significantly larger increase (p = 0.02) in the mean tear size in the newly symptomatic group (10.6 mm) when compared with the still-asymptomatic group (3.3 mm). The rate of progressing to advanced muscle atrophy was higher (p = 0.08) in the newly symptomatic group (35% [six of seventeen subjects]) when compared with the still-asymptomatic group (12% [three of twenty-five subjects]). The rate of fatty degeneration was significantly higher (p = 0.02) in the newly symptomatic group (35% [six of seventeen subjects]) when compared with the still-asymptomatic group (4% [one of twenty-five subjects]). The rate of pathology of the long head of the biceps tendon was significantly higher (p = 0.02) in the newly symptomatic group (33% [six of eighteen subjects]) when compared with the still-asymptomatic group (6% [two of thirty-two subjects]).


CONCLUSIONS
During a relatively short-term follow-up, a substantial percentage of asymptomatic rotator cuff tears became symptomatic and underwent anatomic deterioration. Increase in tear size and decrease of muscle quality were correlated to the development of symptoms. Subjects diagnosed with an asymptomatic rotator cuff tear should be informed about the natural history of the condition and follow-up with repeated imaging may be indicated to monitor tear progression.