Given the close anatomic relationship of the biceps tendon and pulley to the subscapularis, there is often concomitant pathology. Arai et al. reported that of all biceps tendon lesions, 76% were associated with a subscapularis tear, and all unstable biceps tendons also had subscapularis tears [5]. Another investigation found that a subscapularis tear was significantly associated with biceps tendon lesions [12]. Because of this, and particularly in older patients with degenerative tears, a biceps tenodesis or tenotomy is often performed, especially in light of evidence that tenodesis for tenotomy was associated with improved subjective and objective results in a cohort of patients undergoing subscapularis repair [42].

Once the extent and anatomy of the subscapularis tear has been identified, the surgical construct can be determined. A distinction is made between partial-thickness tears (Fig. 25.2a), small full-thickness tears (Fig. 25.2b), and large full-thickness tears with retraction (Fig. 25.2c). A similar but slightly more detailed classification system which divides the subscapularis insertion on the lesser tuberosity into four distinct facets has been proposed [7]. In general, the author utilizes a single-anchor construct for partial-thickness tears, while a double-row construct is used for small and large full-thickness tears. In the author’s experience, and in agreement with previously published literature [43], most chronic and retracted subscapularis tears can be repaired arthroscopically given appropriate mobilization techniques. Denard et al. have also shown that medialization of the lesser tuberosity footprint by as much as 7 mm does not result in negative clinical consequences [44].

Following assessment of the tear pattern and mobility, an additional anterosuperolateral working portal is created off the edge of the anterolateral acromion using outside-in technique. The portal should allow an approximately 10° angle of approach to the lesser tuberosity and be mostly aligned with the subscapularis tendon. The exception to this has been in the setting of isolated partial-thickness tears where a coracoplasty is not required, and a single-anchor repair is planned. In this circumstance, the author does not create additional anterosuperolateral portal so as to remove the possibility of damage to the anterior aspect of the supraspinatus tendon. For these cases, a larger cannula may be exchanged for the initial smaller cannula placed anteriorly. After preparation of the footprint, a free suture is passed in mattress fashion through the superolateral border of the tendon using a suture-passing device (Fig. 25.3a). The two suture limbs (exiting the anterior aspect of the tendon) are then placed through the eyelet of a knotless suture anchor and secured to the superolateral aspect of the lesser tuberosity footprint (Figs. 25.3b, c).

For full-thickness tears, mobilization of the tendon is required, and the additional anterosuperolateral portal is created. Working through this portal, the coracoid tip is identified, paying careful attention to the presence of nearby neurovascular structures, and a window in the rotator interval can be created to give access to the anterior aspect of the tendon. The tip and posterolateral base of the coracoid is skeletonized, proving for and giving access to anterior and superior releases. The need for coracoplasty can be determined at this time. Posterior releases can be achieved using a blunt elevator inserted between the subscapularis and anterior glenoid neck. In chronic and retracted tears, the “comma sign,” a convergence of the superior glenohumeral ligament and coracohumeral ligament, can aid in identification of the superolateral aspect of the torn tendon (Fig. 25.4) [45]. This tissue can hold a traction stitch to aid in releases and mobilization of the tendon and should be preserved in the final repair.

The author’s preferred construct for a full-thickness tear is a double-row knotless repair (Fig. 25.5). Ide et al. reported on a group of patients undergoing subscapularis repairs using either a single-row or double-row technique [46]. While they found that the clinical outcomes for these 61 patients were comparable, subscapularis function and abduction strength were improved in the double-row group, and there was a trend toward a lower failure rate in this same group. For smaller full-thickness tears, a single anchor is placed at the medial aspect of the exposed footprint. For larger tears where more of the footprint is exposed, an inferior and a superior anchor are placed. The anterior portal may need to be adjusted, or a new anterior portal can be created using outside-in technique to allow for appropriate angle for anchor placement. With the use of a grasper or traction stitch through the anterosuperolateral portal to place tension on the subscapularis, a suture-passing device is utilized to pass each suture limb, from inferior to superior, through the tendon in a mattress configuration. Each limb is then secured with a single knotless anchor to the superolateral aspect of the lesser tuberosity footprint. As mentioned, nearly all subscapularis repairs, even with significant fatty infiltration, are able to be repaired with appropriate releases with or without footprint medialization. In the truly irreparable tears, pectoralis major transfer remains an option [47, 48].