Data from a study published in the May 17 issue of The Journal of Bone & Joint Surgery suggest that progression of fatty muscle degeneration may be more likely in rotator cuff tears that are larger at baseline, enlarge over time, and undergo a larger magnitude of enlargement. 

The research team conducted a prospective study of 156 shoulders with full-thickness rotator cuff tear, 70 of which had measurable fatty muscle degeneration of at least one rotator cuff muscle at some time point. They found that overall, patients with fatty muscle degeneration in the shoulder were older than those without degeneration, and the median size of the tears at baseline was larger in shoulders with degeneration than in shoulders that did not develop degeneration. In addition, tears with fatty muscle degeneration were more likely to have enlarged during follow-up compared to tears that never developed muscle degeneration. The median time from tear enlargement to progression of fatty muscle degeneration was 1 year for the supraspinatus and 1.1 years for the infraspinatus muscle. Learn more...