Different classification has been proposed for subscapularis tear classification. Generally, the subscapularis tears could be classified as partial or complete, retracted, and no retracted. The more recent classification of Lafosse classification distinguishes subascapularis tears into five types: type I tear is a simple erosion of the upper third of the tendon without any disconnection to the bone; type II is a complete lesion of the superior one-third of the tendon; a type III lesion is characterized by involvement of all the insertion of the tendon without detachment of the lower third of the muscular portion. In type IV tears, the subscapularis tendon is completely detached from the lesser tuberosity and the humeral head is centered within the joint, and fatty degeneration less than or equal to stage 3. In a type V lesion, the lesion is complete, the humeral head is translated anteriorly and superiorly, with coracoid impingement and fatty degeneration of the muscle fibers of the subscapularis more than stage 3 [12].

The clinical presentation for injury of the subscapularis tendon are extremely variable, particularly because the injury could be acute and traumatic versus degenerative.

Patients with tears of the subscapularis may complain of achy, anterior shoulder pain as well as weakness with abduction and internal rotation. Tenderness in the anterior region over the bicipital groove and lesser tuberosity is very common, particularly in acute cases. In chronic cases, this could be confounding just because symptoms related to LHBT are commonly associated with cuff pathology. Tucking one’s shirt in the back may be particularly troublesome as this requires coupled internal rotation and extension. Since the proximal LHBT derives medial stability from the subscapularis tendon insertion, biceps tendon symptoms may be present with a subscapularis tendon tear.

Examination findings include increased passive external rotation, especially in adduction, as well as loss of internal rotation strength. The “Belly-Press” test (or Napoleon test), where upon the patient attempts to apply pressure to the abdomen while maintaining a straight wrist, has been shown to be reasonably sensitive for subscapularis tears. A decrease in the ability to maintain a forward position of the elbow compared with contralateral side is also considered positive for insufficiency of subscapularis tendon. This test and lift-off test has been described by Gerber et al. [9]. A prerequisite to perform the lift-off test is that patient should have a minimal pain with motion and should be able to internally rotate the arm. A positive test occurs when the patient is unable to lift or maintain the hand away from the back.

The “Bear-Hug” test, first described by Barth et al. [13] has been shown by Chao and Thomas et al. [14] to be perhaps the best test for detecting upper subscapularis tendon tears. To perform this maneuver, the examiner asks the patient to place the involved side hand on the contralateral shoulder with the elbow in 45° of forward flexion and the fingers extended. The patient then attempts to resist an external force by trying to pull the hand away from the shoulder in a perpendicular fashion. The test is positive when the patient is unable to put the hand on the opposite shoulder or shows weakness compared with contralateral shoulder. The bear-hug test is particularly sensitive and specific for tears of the upper subscapularis. Sometimes this test could be only painful, but this is not sensitive for a subscapularis tear.

About the imaging, plain radiographs (X-ray) are the initial studies required for patients with a suspected rotator cuff tear. X-rays normally are negative and do not give direct information of a subscapularis tear. In case of long-standing massive rotator cuff tear, a superior migration of humeral head could be observed, or in case of subscapularis chronic tear, a reduction of the coracohumeral distance can also be observed. Additional studies, however, are necessary to evaluate subscapularis, including magnetic resonance imaging (MRI), MRI with intrarticular contrast injection (arthro-MRI), CT arthrography (CTA), and ultrasonography (US).

The US could be able to detect a tear of subscapularis and allows dynamic evaluation of the tendon and LHBT. However, it does not have any ability to show fatty infiltration, muscle atrophy, and grade of tendon retraction. The presence of fatty infiltration and muscle atrophy has been correlated with a bad prognosis after repair. According to some authors [7], CT scan with or without arthrography is very useful to diagnose the injury of anterosuperior rotator cuff. About the MRI, Tung et al. reported that only 31 % of subscapularis tears confirmed at arthroscopy were detected at preoperative time on standard MRI [15] (Fig. 5). In particular, the small tears were frequently missed, whereas tears involving 50 % or more of the tendon insertion were more readily detected. Another study confirmed these findings, even when arthro-MRI was used. In this study, subscapularis tears were identified in 40 shoulders at the time of arthroscopy, whereas a lesion was identified in only 15 shoulders in a preoperative MRI. These findings indicate that sensitivity to identify subscapularis tears does not dramatically increase even with the use of arthrography, particularly in case of smaller partial thickness tear [16].

Different considerations should be done before to discuss the options of treatment. First of all, as with the other tendons of rotator cuff, in cases with a small, degenerative tear in low-demand patients, a conservative treatment could be attempted. No steroidal anti-inflammatory drugs, injections, and physical therapy to improve pain and function are the mainstay of this treatment. On the other hand, an acute traumatic tear of the subscapularis muscle more typically should be repaired surgically as soon as possible. This tendon, in fact, is prone to retraction and early irreversible changes of the muscle. Inferior clinical results have been reported with delayed repair of subscapularis tear, and, in many cases, the subscapularis was found not repairable at the time of surgery [17]. As discussed before, the anterosuperior tear often results by a traumatic event. Often, these patients come to our attention because of pain, loss of function, and stiffness after a trauma. Stiffness could be probably related to the proximity of LHBT and rotator interval. These patients could be treated with physical therapy and planned repair. During surgery, a release of rotator interval should be done. Some authors believe that, given the critical role of the subscapularis in glenohumeral kinematics, even in the presence of a complete long-standing tear with a substantial fatty infiltration, an attempt to repair the subscapularis also for its tenodesis effect should be done [18, 19]. Other authors, however, think that patients with evidence of fatty degenerated subscapularis tendon, associated massive posterior rotator cuff tear, or with a static anterior subluxation of humeral head should not undergo a repair operation.