Different considerations should be done before discussing the options of treatment. First of all as with the other tendons of rotator cuff, in cases with a small, degenerative tear with a well-compensated shoulder function in a low-demand patient, 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, dysfunction of the entire subscapularis is a risk factor for pseudoparalytic shoulder. For function to be preserved in patients with anterosuperior rotator cuff tears, it may be important to avoid fatty infiltration with anterior extension into the lower subscapularis tendon (Collin et al. 2014). Without treatment, rupture of the subscapularis leads to pain, loss of function, and shoulder weakness. In the long term, dynamic anterior instability can lead to the development of glenohumeral arthrosis (Flury et al. 2006). In consequence, an acute traumatic tear of the anterosuperior rotator cuff more typically should be repaired surgically as soon as possible. Subscapularis tendon in particular 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 (Mansat et al. 2003). As discussed before, the anterosuperior tear often results by a traumatic event. Often these patients coming 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 (Denard et al. 2011; Koo and Burkhart 2012). Other authors, however, think that patients with evidence of fatty degenerated subscapularis tendon associated with a static anterior subluxation of humeral head should not undergo a repair operation.

The biomechanical rationale to repair the subscapularis becomes most important in case of an anterosuperior rotator cuff tear. The anterior part of supraspinatus and superior part of subscapularis are connected by a comma-shaped arc of tissue called the comma sign. The comma sign is very helpful to find the subscapularis tendon particularly in chronic case when the subscapularis retract medially to the glenoid. The comma sign represent the superior glenohumeral ligament and the medial segment of the coracohumeral ligament that are torn off the humerus at the upper border of the subscapularis footprint (Lo and Burkhart 2003; Visonà et al. 2015a). Repairing the upper part of subscapularis together with comma system restores a part of the anterior attachment of the rotator cable. Recently, however, some authors noted that in patients treated with arthroscopic repair of anterosuperior tears of the rotator cuff, the technique of in-continuity repair did not produce better clinical outcomes or structural integrity than the technique involving disruption of the tear margin. If the muscle in an anterosuperior rotator cuff tear is of good quality, it does not appear to matter whether the tear margin between the subscapularis and supraspinatus is preserved or disrupted (Kim et al. 2014).

For the repair of anterosuperior rotator cuff tear, arthroscopic and open technique has been described.

Open technique could be a good option in rare case of isolated traumatic tear of subscapularis tendon particularly when the lesion involves all the length of the subscapularis (tendon and muscular portion). Open surgery is also indicated for management of extra-articular lesions or tears involving the myotendineous portion (Di Schino et al. 2012).

Anterosuperior rotator cuff tear can be arthroscopically repaired with the patient in a beach chair or lateral decubitus position (Fig. 19.2). We use three or four portals to work around the shoulder: posterior, anterosuperior, and one or two subacromial portals. We use a 30° arthroscopy all the time of the procedure. Proper manipulation of the arm can be useful for visualizing the subscapularis. Bringing the arm into forward and internal rotation could be useful to examine the tendon.

In the lateral decubitus, the so-called posterior lever push in which the assistant applies a lever from anterior to posterior associated with an internal rotation could help to better visualize the tendon and the extent of the lesion.

Once the lesion is identified, we start to prepare and repair.

In case of acute on chronic case and in any case with a retracted subscapularis tendon, we prefer to repair anterior part of the cuff through an intra-articular approach using the suture anchor technique with or without in-continuity repair (Fig. 19.3). This depends from pattern of tear, from grade of retraction of the subscapularis and supraspinatus tendon, and from the tissue quality. One posterior and one anterosuperior portal could be enough to treat this tear. One or two triple loaded suture anchors using a mattress stitch associated with two simple stitches could be used. Suture could be passed with different tools according to the preference of surgeon. In general one anchor per linear centimeter of torn tendon should be used. When using anchors most subscapularis tears could be repaired with a single-row technique with good results (Fig. 19.4) (Ide et al. 2007). There is a high correlation between subscapularis tear and LHBT pathology, and often the LHBT pathology should be treated and at the same time the subscapularis tendon pathology. If the LHBT is altered in the groove, a tenotomy or an associated tenodesis (subpectoral tenodesis) with a screw could be done working once the subscapularis tendon is repaired, on the anterior space of the shoulder. In case in which the LHBT is just unstable without any pathology in the groove, an associated tenodesis at the anchor used to repair the subscapularis tendon is carried out.

Whenever it is possible, in case of anterosuperior rotator cuff, we prefer to use transosseous repair. In particular this technique is done in case in which the tendons are not so much retracted or stiff and the technique of in-continuity repair could be used. In this case, we start tissue mobilization during the articular phase of arthroscopy. The subscapularis is mobilized and a traction stitch is used to assist in the reduction. Then the scope is moved into subacromial space (Fig. 19.5). The space is cleaned and the superior cuff is freed from adhesions. The footprint of tendon is prepared. Different tunnels could be made, according to the size of tear, using the ArthroTunneler™ (Tornier, Edina, MN) device (Garofalo et al. 2012) We perform the repair with the scope in posterolateral portal and using as working portal the anterolateral, anterior, and posterior portals. In case of anterosuperior tear with the interval in continuity, we prefer to not disrupt the margin between the supraspinatus and subscapularis, and we pass the anterior sutures to repair the most anterosuperior part of tear altogether (Fig. 19.6). This technique of repair is more easy and fast to do. Furthermore, this allows to reapproximate the superior cuff (Fig. 19.7).