Repair of the subscapularis requires working in the subcoracoid space. Since this space can become compromised rapidly by soft tissue swelling from fluid extravasation, it is critical to address the subscapularis prior to repairing the rest of the cuff. In general, when the subscapularis is torn, the order of steps is as follows:

The patient is placed in the lateral decubitus position and the arm is placed in balanced suspension or an articulating arm holder at 20–30° of abduction and 20° of forward flexion. The subscapularis is initially inspected with a 30° arthroscope viewing through a posterior portal. During subscapularis tendon repair, we view exclusively through a posterior portal and switch between 30° and 70° arthroscopes as needed.

Retracted tears are the most obvious and are located by a torn medial biceps sling which creates a “comma sign.” [13] The medial sling, composed of the medial coracohumeral ligament and the superior glenohumeral ligament, normally inserts at the superior lesser tuberosity adjacent to the superolateral subscapularis footprint (Fig. 19.2). When the upper subscapularis tears away from its bone attachment, the medial sling also tears away from the bone and forms a distinctive comma-shaped arc of soft tissue (comma sign) at the superolateral corner of the subscapularis (Fig. 19.3). Identification of this structure therefore always leads to the superolateral subscapularis tendon, even when the tendon is severely retracted and adhesed medially. If the subscapularis tendon is not immediately visible at the front of the joint, it is probably retracted medially to the level of the glenoid margin. It can usually be located by placing the tip of a blunt instrument (e.g., a switching stickor shaver introduced through an anterosuperolateral portal) into the soft tissue adjacent to the glenoid rim at the level of the mid-glenoid notch. The mid-glenoid notch is the level at which the upper border of the subscapularis tendon usually crosses transversely. The tip of the switching stick is used to hook into the junction where the superolateral border of the subscapularis tendon joins the comma tissue at approximately a right angle.

With a posterior viewing portal, the subscapularis footprint can only be fully visualized by using a 70° arthroscope. Visualization can also be enhanced with a posterior lever push and internal rotation of the arm. In the case of retracted tears, the lesser tuberosity will be bare.

With the exception of very young individuals and throwing athletes, we routinely perform a biceps tenodesis in conjunction with repair of a subscapularis tear. Tenotomy is reserved for patients over the age of 70 or with multiple comorbidities. Poorer results have been reported when the biceps is left in place in the setting of subscapularis repair [14]. After identifying a subscapularis tear, an anterosuperolateral (ASL) portal is established viewing with a 30° arthroscope, using an 18-gauge spinal needle as a guide. This portal is typically 1–2 cm lateral to the anterolateral acromion but can vary, and placement should be such that it provides a 5°–10° angle of approach to the lesser tuberosity and is parallel to the subscapularis tendon. An 8.25 mm threaded clear cannula is placed in this portal.

Our technique for arthroscopic biceps tenodesis is briefly summarized here but has been described in detail previously [15]. Through the ASL portal, 2 half-racking #2 FiberWire (Arthrex Inc., Naples, FL) sutures are placed as traction sutures in the biceps tendon and then a tenotomy is performed. The biceps is then exteriorized, secured with a whipstitch, sized, and left outside of the ASL portal for later tenodesis. Performing the biceps tenotomy first provides greater access to the subscapularis insertion.

Accessing the subcoracoid space is an essential component of subscapularis repair. A 30° arthroscope is used to initially locate the coracoid tip. Using the 30° arthroscope helps to maintain proper orientation so as to avoid inadvertent dissection as all important neurovascular structures are greater than 2.5 cm from the tip of the coracoid [16]. In non-retracted tears, the coracoid tip is usually just anterior to the upper subscapularis tendon and can be palpated with an instrument inserted through the ASL portal. A shaver or electrocautery is used to make a window in the rotator interval just superior to the subscapularis tendon and medial to the comma tissue. We strongly believe it is important to preserve the comma tissue during this step because of the connection to the supraspinatus tendon and its ability to afford margin convergence suturing to the posterior cuff.

With retracted tears, the tendon is usually initially resting medial to the coracoid, and the coracoid tip is frequently hidden behind bursal leaders that extend from the lateral border of the subscapularis to the anterior internal deltoid fascia. These bursal leaders must be released to access the subcoracoid space. Once the comma sign is identified, an electrocautery can be used to free these adhesions by working parallel and slightly anterior to the comma tissue. Usually after just a few sweeps of the electrocautery, the conjoined tendon and coracoid tip will be visualized, providing access to the subcoracoid space. A 70° arthroscope is then inserted and attention is turned to the 3-sided release. The 70° arthroscope offers a much wider field of view medially for skeletonizing the coracoid neck and coracoid base.

Retracted tears of the subscapularis require a three-sided release. A traction suture is placed in the superolateral tendon medial to the comma tissue using an antegrade suture passer (FastPass Scorpion; Arthrex, Inc., Naples, FL). In order to maintain freedom in the ASL working portal, it is helpful to briefly remove the cannula and replace it so that the traction suture remains in the ASL portal but outside of the cannula. A hemostat can be placed on the traction stitch to separate it from the biceps whipstitch sutures which exit the same portal. While pulling laterally on the traction suture, the coracoid is then identified and a window is created in the rotator interval as described previously (Fig. 19.4).

The posterolateral coracoid tip is skeletoniz ed with an electrocautery and a shaver is used to remove the fibrofatty bursa between coracoid and the anterior aspect of the subscapularis tendon. This step constitutes the anterior release.