Review Question - QID 219803

The patient has a subscapularis tear with medial retraction of the biceps tendon, indicating injury to the biceps sling or "pulley," which is composed of rotator interval tissue, including the coracohumeral ligament (CHL) and superior glenohumeral ligament (SGHL) (Answer 5).

Subscapularis tears often occur as acute avulsion injuries in younger patients and are associated with hyperabduction and external rotation moments. Clinically, patients present with loss of active internal rotation and excessive passive external rotation. Given the mechanism, the medial biceps sling is often involved due to injury to the rotator interval tissue, which produces a characteristic arthroscopic sign known as the "comma sign." Resultant medial subluxation of the biceps tendon with disruption of the biceps pulley creates an unstable intra-articular tendon that must be addressed surgically with either a tenotomy or tenodesis in order to prevent jeopardizing the outcomes of concomitant subscapularis tendon repair.

Godenèche et al. reviewed the relationship between subscapularis tears and injuries to the biceps pulley. The authors prospectively reviewed 218 arthroscopic cases in an attempt to prove that the bicipital pulley might remain intact, even in the case of a subscapularis tear. They found that a pathologic long head of the biceps tendon (LHBT) with an intact SGHL/CHL complex was observed in only 25 of the 218 patients (11%) but that even in these cases, the medial wall of the bicipital sheath was torn in 92%. They concluded that in cases of a tear associated with a lesion of the SGHL/CHL complex, the LHBT is nearly always unstable and pathologic.

Varacallo et al. reviewed the concept of biceps tendon dislocation and instability. The authors note that as the LHBT takes a 30° turn as it heads toward the supraglenoid tubercle, it relies on the integrity of the enveloping soft tissue sling/pulley system. They conclude that the most essential elements in maintaining stability at this critical turn angle are the most medial structures at the proximal-most aspect of the groove's exit point: the subscapularis, supraspinatus, coracohumeral ligament (CHL), and superior glenohumeral ligament (SGHL).

Lo et al. reviewed the "comma sign" as an arthroscopic guide to the torn subscapularis tendon. The authors note that although subscapularis tears are becoming increasingly recognized as a cause of shoulder pain and disability, identifying the subscapularis tendon stump is often difficult during the repair of chronic, retracted subscapularis tears that are scarred to the deltoid fascia. They conclude that the "comma sign," which represents an arc formed by a portion of the superior glenohumeral ligament/coracohumeral ligament complex, is a useful marker of the superolateral corner of the torn subscapularis tendon.

Figure A is an axial proton-density, fat-saturated MRI sequence demonstrating a subscapularis tear with medial subluxation of the long head of the biceps tendon.

Incorrect Answers:
Answers 1-4: The coracohumeral ligament (CHL) and superior glenohumeral ligament (SGHL) form the "comma" tissue that supports the biceps sling, not the CA ligament or the MGHL/IGHL.