Fatty change and muscle atrophy in patients with rotator cuff tears: a prospective study with a mean 6-year follow-up

Background: Understanding how fatty change and muscle atrophy progress-and how they are interrelated-is important for determining appropriate treatment strategies in patients with rotator cuff tears. To prospectively evaluate the relationship between supraspinatus muscle atrophy and fatty change in patients with symptomatic rotator cuff tears treated nonoperatively, using magnetic resonance imaging. Methods: Among 225 patients with symptomatic rotator cuff tears treated nonoperatively between 2006 and 2015, 58 patients (59 shoulders) who underwent at least two magnetic resonance imaging evaluations and were followed for ≥30 months were included. The occupation ratio (cross-sectional area of supraspinatus/supraspinatus fossa) was calculated to assess muscle atrophy, and fatty change was graded using the Goutallier classification. Tear dimensions (length and width) were also measured. Results: = .020). Conclusion: Fatty change progressed in 7 shoulders (12%) during an average duration of 53 months. It was strongly associated with larger baseline tear size, tear enlargement, and muscle atrophy progression, highlighting the importance of early identification.