69-year-old patient presenting with anterior shoulder pain, weakness, and functional limitation. Symptoms likely progressive and associated with rotator cuff pathology.
Ultrasound examination of the shoulder demonstrates medial (sub)luxation of the long head of the biceps tendon. The tendon is displaced medially and appears to lie over the tuberculum minus, consistent with instability of the biceps pulley system.
The biceps tendon is markedly thickened and demonstrates significant tendinopathy. There is associated moderate tenosynovitis of the biceps tendon sheath, with clear neovascularization, indicating an active inflammatory process.
There is thickening of the subacromial-subdeltoid (SASD) bursa at the level of the rotator interval, suggestive of reactive bursitis.
The subscapularis tendon shows a moderate full-thickness tear involving part of the tendon width (partial-width), located at its insertion on the tuberculum minus. This finding explains the medial instability of the biceps tendon, as the subscapularis plays a key role in stabilizing the bicipital groove.
Additionally, there is a large full-thickness tear involving the supraspinatus–infraspinatus junction, also partial in width, with clear disruption of the tendon continuity.
Overall, these findings are consistent with advanced rotator cuff pathology with associated biceps instability.
1. Final diagnosis
Medial dislocation of the long head of the biceps tendon due to failure of the biceps pulley system, associated with a partial-width full-thickness subscapularis tear and a large partial-width full-thickness tear of the supraspinatus–infraspinatus junction, with accompanying tendinopathy and tenosynovitis.
2. Differential diagnosis
Consider isolated biceps instability without rotator cuff tear, although this is unlikely given the clear subscapularis involvement. Chronic degenerative cuff disease versus post-traumatic pathology should also be considered.
3. Teaching points
Medial dislocation of the biceps tendon is strongly associated with subscapularis tears and pulley lesions. Evaluation of the biceps position is crucial in shoulder ultrasound. Combined rotator cuff tears are common in advanced disease and should be systematically assessed.
4. Injury/disease information
The stability of the long head of the biceps tendon depends on the integrity of the biceps pulley system, including the subscapularis tendon. Disruption of these structures can lead to medial dislocation of the tendon. Chronic rotator cuff tears often coexist and contribute to pain, instability, and functional impairment.
Marc is founder of, and trainer at, SonoSkills. SonoSkills is an organization dedicated to MSK ultrasound education. He's also an MSK Sonographer at EchoConsult in Roermond, the Netherlands.
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