Clin Should Elbow.  2011 Dec;14(2):159-164.

Relationship of the Sagittal Extent of Rotator Cuff Tears to the Grade of Fatty Degeneration of the Rotator Cuff Muscles

• Seo JB
• Kim MH
• Yi JM

Abstract

PURPOSE
To investigate the relationship between the size of a rotator cuff tear and the grade of fatty degeneration of the supraspinatus and infraspinatus muscles.
MATERIALS AND METHODS
From a database of 541 patients who underwent a shoulder MRI between September 2004 and September 2010, we enrolled 148 patients that had a full-thickness rotator cuff tear. The anteroposterior diameter of the tear was measured in sagittal views on an MRI. The patients were divided into 6 groups reflecting the anteroposterior diameter: group 1 (a width of <10 mm), group 2 (10 mm< or =width<15 mm), group 3 (15 mm< or =width<20 mm), group 4 (20 mm< or =width<25 mm), group 5 (25 mm< or =width<30 mm) and group 6 (a width<30 mm). Fatty degeneration was rated according to Goutallier et al.
RESULTS
Fatty degeneration in the supraspinatus and infraspinatus muscles increased with the severity of the rotator cuff tear. The supraspinatus fatty degeneration increased prominently as the tear size increased from 15~19 mm to 20~24 mm and from 25~29 mm to over 30 mm. The infraspinatus fatty degeneration increased prominently as the tear size increased from 25~29 mm to over 30 mm. Seventeen patients had tear widths under 10 mm and 8 patients among them had fatty degeneration of the infraspinatus.
CONCLUSION
Fatty degeneration in supraspinatus and infraspinatus muscles increases prominently at specific tear sizes. The presence of tears under 10 mm with infraspinatus fatty degeneration indicates that the infraspinatus tendon may have an anatomical or functional effect even in small tears.

MeSH Terms

Humans
Muscles
Rotator Cuff
Shoulder
Tendons