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

## TL;DR

This study shows that fatty change in rotator cuff muscles is rare but linked to larger initial tears and muscle atrophy over time.

## Contribution

The study provides new evidence on the progression of fatty change and its association with tear size and muscle atrophy in rotator cuff tears.

## Key findings

- Fatty change progressed in 12% of shoulders over an average of 53 months.
- Larger initial tear length was strongly associated with fatty change progression.
- Muscle atrophy and tear enlargement were linked to fatty change progression.

## Abstract

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.

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.

Muscle atrophy progressed in 40 shoulders (68%), and fatty change progressed in 7 shoulders (12%) during an average duration of 53 months. Fatty change progression was significantly associated with larger initial tear length (25.9 mm vs. 11.0 mm; P < .001). The occupation ratio decreased progressively with higher Goutallier grades (P = .020).

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.