Presentation
Chronic shoulder pain
Patient Data
The subscapularis tendon is thickened with a disturbed fibrillary pattern. It shows a well-defined defect partially interrupting its fibres and containing anechoic fluid suggesting a partial tear. Dynamic examination of the subscapularis tendon in external and internal rotation revealed a limitation of motion below the coracoid suggesting impingement. There is a cortical irregularity of the greater and lesser tuberosities suggesting enthesopathy at the insertion site of both supraspinatus and subscapularis. The supraspinatus tendon is thickened below the acromion. Dynamic examination of the supraspinatus tendon while performing abduction from 15 to 90 degrees revealed mild limitation of motion with delayed passage of muscle fibres below the acromion. Note the osteoarthritic changes of the acromioclavicular joint.
The subscapularis tendon shows a segment of fluid signal interrupting its fibres at its distal part displaying high SI in T2 and intermediate SI in proton-density (PD) weighted images (WIs) suggesting full-thickness partial-width tear. The supraspinatus tendon is torn and retracted to the level of the glenoid. There is fatty atrophy of the superior belly of the infraspinatus. Note the fluid surrounding the Biceps tendon and the osteoarthritic changes of the acromioclavicular joint.
Case Discussion
The diagnosis of subscapularis tendon tears can be difficult. Pre-operative ultrasound is a valuable tool in the initial diagnosis. Ultrasound has a high sensitivity for high-grade tears. It could be used as a simple bedside test before performing MRI. Bicipital peri-tendinous effusion has been correlated with subscapularis tears. Although MRI has been widely accepted as the gold standard for the diagnosis of rotator cuff tears, it also has a low sensitivity for low-grade tears. The combination of both modalities may improve the sensitivity for the diagnosis of subscapularis tears.