The patient showed up 6 weeks and 3 months after surgery. He reported no complications and the pain was significantly reduced (VAS 2–3). However, he showed up again 2 years after the pectoralis tendon transfer with increasing pain (VAS 8–9) and reduced function of the left shoulder. Active forward flection was reduced to 80°. Atrophy of the upper part of the pectoralis major was clearly seen. Also, the trapezius, deltoideus, supraspinatus, and infraspinatus showed visible atrophy. In the meantime, he had surgeries of internal organs with life-threatening complications. During this time, he neglected his shoulder problems. His general health status was further reduced and his weight was 50 kg. MRI of the left shoulder showed that the transferred pectoralis tendon and muscle were very thin with subcoracoid impingement, superior head migration, and ventral subluxation of the humeral head on the glenoid. Because of his reduced general health status conservative treatment with physiotherapy was performed, but the pain and the function did not improve over time. Therefore, after his general health improved and his weight was 53 kg, the arguments for and against surgery were discussed, and since his life expectancy was considered low, he had a low activity level, and his quality of life was low, a reverse total shoulder arthroplasty was performed three years after the pectoralis tendon transfer when he was 62 years old. During operation the transferred pectoralis major tendon was observed to be very thin but intact. However, the signs of subcoracoid impingement, superior head migration, and ventral subluxation of the humerus were clearly seen. The operation was carried out without any complication and the transferred tendon again attached to the lesser tuberosity. The operated shoulder was immobilized for 6 weeks in an abduction pillow. Passive exercises were allowed and supported with a shoulder motion device for 6 weeks for abduction. However, external rotation was limited to 0° for 6 weeks after surgery to protect the pectoralis major tendon and prevent luxations. Active-assisted exercises were allowed after the 6-week point. The patient showed up 6 weeks and 3 months after surgery. He reported no complications and the pain was again significantly reduced (VAS 3). Two years after the reverse total shoulder arthroplasty he reported increased pain (VAS 7) and decreasing function of the left shoulder. Active forward flection and abduction were reduced to 90° (Fig. 12.3). He is able to comb his hair (Fig. 12.4) with strong external rotation but could only reach the lateral hip (Fig. 12.5), because his active internal rotation was markedly reduced. Atrophy of the upper part of the pectoralis major could be clearly seen (Fig. 12.6). On the ventral aspect of the shoulder the arthroplasty can be outlined because the patient is so slim. Also, the trapezius, deltoideus, supraspinatus, and infraspinatus showed visible atrophy (Fig. 12.7). The neurological findings were normal. He had also a rash of the ventrolateral shoulder, but the lab values showed a normal CRP. The X-rays 2 years after surgery show a reverse arthroplasty with no signs of loosening or notching (Fig. 12.8). In the meantime, he again had surgeries of internal organs with life-threatening complications and his weight was again 50 kg. He was asked to follow up closely every 3 months to check on his status.

This example shows that the pectoralis major transfer is not always successful in terms of permanent pain relief, even though the indication was right, based on the current literature. This patient had always only a partial and temporary pain relief after surgery. A reverse shoulder arthroplasty is sometimes the last alternative when pain and function deteriorate over time, but after multiple operations and weakened internal rotators the results are sometimes frustrating.

The majority of rotator cuff tears involve the posterosuperior cuff and can often be treated with repair of the tendons, even months and years after rupture. However, tears of the subscapularis tend to retract fast, and show rapid fatty degeneration of the muscle belly, leading to irreparable situations, especially when the diagnosis is delayed [3, 4, 6].

The subscapularis is an important factor for the muscular force couple of the glenohumeral joint. An insufficiency of the subscapularis caused by a tendon tear or neurologic disorder leaves the humeral head unbalanced, producing functional disabilities [7, 8]. Additionally, chronic and recurrent anterior subluxation and instability with associated pain are characteristics of subscapularis insufficiency [2, 9].

Arthroplasty is a treatment option, depending on the patient’s level of glenohumeral arthritis, age, and activity level, in combination with or without a pectoralis major transfer. Hemiarthroplasty has been attempted with moderate and unreliable pain relief and functional results [10–13]. Recently, reverse total shoulder arthroplasty has become the standard for older and low-demand patients with good clinical results [8]. Depending on the patient’s needs and circumstances other options include arthroscopic debridement with biceps tenotomy or tenodesis to reduce the pain [14].

Although arthroplasty may be the standard in old and low-demand patients, the management of high-demand, active, and/or young patients with an irreparable subscapularis tear is still an important challenge. In these cases, tendon transfers are a feasible option, commonly using the pectoralis major, if the patient has a well-preserved glenohumeral joint [1, 4, 6, 15–19].

The pectoralis major can be transferred using its whole tendon, or it can be split to rebalance the force couple on the humeral head [2–4]. The tendon is then rerouted underneath or left superficially to the conjoined tendon. If rerouted underneath to the conjoined tendon, the pectoralis is thought to additionally reduce subcoracoid impingement through a soft-tissue interposition effect that helps in pain relief. These techniques can be used for subscapularis tears in isolation, for subscapularis tears with anterior supraspinatus tears, or in combination with posterior cuff repair for posterosuperior tears. In addition, they have been used for subscapularis insufficiency after failure of subscapularis repair after open shoulder stabilization or shoulder hemiarthroplasty [20–22]. However, subscapularis insufficiency after hemiarthroplasty presents a significant therapeutic challenge, often because of recurrent instability, with unsatisfactory results [20].