In patients with a rotator cuff insufficiency, the glenohumeral joint can become uncompensated. Depending on the number of the involved insufficient rotator cuff tendons, the shoulder range of motion is impacted in the sagittal and/or vertical plane. Because the shoulder joint is unbalanced in its natural state in both the vertical plane (deltoid stronger than the rotator cuff muscles) and the horizontal plane (four internal rotators stronger than two external rotators), this only becomes worse with aging. The aging shoulder often shows rotator cuff tendon wear, mostly including the supraspinatus and infraspinatus tendons first. That leads to unopposed cranial pull, creating an unbalanced shoulder in the vertical plane (Fig. 41.1). Because the humeral head continues to rise, this creates a cascade of glenohumeral destruction that can be followed by the Hamada classification of rotator cuff arthropathy. Patients with an isolated loss of active elevation or a so-called pseudo paralysis, which describes the painless inability to abduct the arm to 90 degrees while maintaining a normal passive range of motion in the absence of neurologic impairment (Fig. 41.2), are best treated with a reverse shoulder arthroplasty. Reverse shoulder arthroplasty moves the center of rotation distally and medially, allowing the deltoid to effectively transmit moments across the glenohumeral joint and thereby allowing improved forward flexion in a predictable fashion and a rebalancing of the vertical plane of motion.

As the arthropathy worsens, the infraspinatus and teres minor (if atrophic or in some cases torn) can become insufficient, resulting in a horizontal imbalance (Fig. 41.3A,B). This causes profound disability that reverse shoulder arthroplasty alone may not sufficiently address. This pattern may result in a combined loss of active elevation and external rotation (CLEER) and rarely may just be found to be an isolated loss of external rotation.

The shoulder itself has a natural predominance to internal rotation (IR) if each function of traversing muscle is reviewed. There are four internal rotators (the pectoralis major, the latissimus dorsi, the teres major, and the subscapularis), whereas there are only two external rotators (the teres minor and the infraspinatus). In the setting of a posterior cuff tear, it is easy to understand how a horizontal imbalance can occur with disruption or partial disruption of either of these external rotators. However, even in the setting of a two-tendon rupture, the teres minor—the dominant external rotator providing up to 40% of strength of external rotation—can experience atrophy in 24% of the cases, further reducing its ability to balance the shoulder. The loss of these muscles creates an environment of four stout internal rotators versus zero. Thus, a rebalancing of the shoulder is imperative in this setting.

In patients with a pseudo paralysis, who additionally have a horizontal imbalance as a consequence of their teres minor and infraspinatus insufficiency (patients with CLEER), activities of daily living are often drastically impacted. The ADLER (activities of daily living [ADL] that require active external rotation [ER]) score was suggested as an objective method to score a patient’s disability by judging their ability to perform everyday tasks, which are dependent on the external rotation of the shoulder (Table 41.1, Fig. 41.4). Simple tasks, such as shaving, brushing teeth or combing hair, eating, drinking, or opening doors, are classically affected. Therefore in patients with this dysfunction, a tendon transfer in conjunction with the reverse shoulder arthroplasty is indicated.

In 1934, L’Episcopo first described the technique of transfer of the latissimus dorsi and teres major (LD/TM) tendons in children with obstetric palsy. The procedure involves transferring both tendons laterally and posteriorly on the humerus, such that the function of the LD/TM changes from internal to external rotation (Fig. 41.4A,B). The technique was modified so that it could be performed through a single deltopectoral approach. In the literature, this technique has been established as a viable treatment option for these patients. Alternatively, it is also possible to perform a latissimus dorsi transfer combined with a reverse total shoulder arthroplasty using a two-incision technique with results similar to those described by Gerber et al. In a variation of these two known and established techniques, a latissimus dorsi transfer only through a single-incision technique was recently performed by the authors with equal restoration of the external rotation and even with better IR ability. In the following section, the single-incision modified L’Episcopo (LD/TM) and the single-incision LD transfer only as a variation are described.