The patient is positioned in a modified or lazy beach chair position (FIGURE 13.1). Care is taken not to elevate the head higher than 30° to 40°. Less flexion helps facilitate the visualization of the assistant on the superior side of the shoulder. The patient should be placed far enough on the lateral side of the table to allow free motion of the arm, including free extension of the arm to 90° for visualization and preparation of the humeral canal. All bony prominences should be padded appropriately, and the head should be securely stabilized. After positioning, the range of motion of the shoulder is assessed to guarantee adequate ability to manipulate the arm as needed during the surgery. During the surgical procedure, the arm may be placed in one of many commercially available arm holders. My preference is to place the arm free on a padded Mayo stand. The Mayo stand allows the surgeon to shift the arm position freely during the procedure, as well as removing and replacing the stand throughout the surgery.

Retractor selection is critical in obtaining adequate exposure. Multiple combinations of retractors can be used effectively. Each surgeon may identify a combination of retractors that works well for their specific needs. As a general rule, smaller and fewer retractors may be helpful when working in the shoulder where space is limited. Particularly with glenoid exposure, it is helpful to have not only an initial set of retractors but also alternative retractors, which may be useful in patients with unique anatomic challenges. Each surgeon is encouraged to experiment with multiple retractor combinations in various anatomic situations. Our standard retractors include the following (FIGURE 13.2): a Darrach for sweeping the subacromial and subdeltoid spaces, as well as levering the humeral head; a Browne deltoid retractor; a posterior humeral head retractor; various Richardson retractors; multiple 2-point retractors; a bent spiked Hohmann; various posterior glenoid retractors; and a self-retaining deltoid retractor with multiple blades.

For primary anatomic arthroplasty, I use a standard deltopectoral approach. The deltopectoral approach is familiar to most surgeons and allows for an extensile approach as needed in revision cases. This approach provides excellent exposure of both the humeral and glenoid side of the joint while preserving the deltoid and protecting the surrounding neurovascular structures. Landmarks for the skin incision include the coracoid, distal one-third of the clavicle, and the distal deltoid insertion. A straight skin incision is made directly over the coracoid following the predictable path of the deltopectoral interval (FIGURE 13.3). Small subcutaneous flaps are raised on either side of the incision as well as proximally and distally. The cephalic vein is identified and used as a landmark for the deltopectoral interval. If the cephalic vein is absent, then the interval can be identified by palpating just proximal to the coracoid and identifying a small triangle devoid of muscle tissue between the pectoralis major and the deltoid.¹ This step can be facilitated by externally rotating the arm and putting the pectoralis major fibers on stretch. When present, the cephalic vein may be taken either medially or laterally. My preference is to mobilize the vein laterally with the deltoid. Lateral mobilization of the vein prevents the need for coagulation of multiple branches that enter laterally from the deltoid. However, this places the vein under more tension throughout the procedure. To prevent injury in cases where the vein has been taken laterally, it is helpful to mobilize the vein proximally toward the clavicle and distally well past the pectoralis major muscle insertion. After the development of the deltopectoral interval, the deltoid is retracted laterally with a Richardson retractor, and the deep landmarks are identified, including the coracoid, conjoined tendon, coracoacromial ligament, rotator interval, biceps tendon, and pectoralis major tendon insertion (FIGURE 13.4).
A Darrach retractor or the surgeon’s index finger is used to mobilize and connect the subacromial and subdeltoid spaces. A Browne deltoid retractor is placed beneath the deltoid in the subacromial and subdeltoid spaces. At this point, the surgeon sweeps the subcoracoid space between the conjoined tendon and the subscapularis for placement of the blades of a self-retaining deltoid retractor. During this step, it is helpful to identify the axillary nerve with the tip of the surgeon’s index finger. “Tug test” (FIGURE 13.5) can be helpful here in identifying the location of the axillary nerve, which is at some risk during the remainder of the procedure. Familiarity with the location of the nerve can help minimize the risk of injury throughout the case.²

The humeral insertion of the pectoralis major tendon is located. The release of the upper portion of the pectoralis tendon facilitates exposure of the lower one-third of the subscapularis tendon (FIGURE 13.6). In unusually large or excessively stiff patients, further release of the pectoralis tendon improves exposure. In rare cases of difficult exposure, if necessary, the entire tendon may be released, greatly enhancing the posterior displacement of the humerus and thereby improving glenoid exposure. It is helpful to leave as much of the identifiable tendon on the insertion of the humeral side for later repair. The dorsal side of the pectoralis major tendon has additional tendon fibers not visible from the ventral approach. A tag suture placed on the superior border of the muscular side of the tendon aids with retraction and helps align repair during the closure. After the removal of any excessive clavipectoral fascia, the border of the subscapularis should be visible. Superiorly, the rotator interval is identified by finding the soft spot just below the confluence of the conjoined tendon and the coracoacromial ligament. External rotation of the arm can assist in locating the interval. Opening the interval allows for visualization of the biceps tendon. Tracing the biceps tendon distal to the upper border of the pectoralis
major tendon locates the lateral border of the subscapularis. The anterior humeral circumflex vessels denote the inferior border. Once the anterior humeral circumflex vessels are identified, they should be ligated or cauterized at the level of the humeral neck.

Attention is then turned toward the management of the long head of the biceps tendon. The tendon should be released, and the intra-articular portion is removed in all cases, as it may serve as a source of pain and stiffness postoperatively. After release, a biceps tenodesis is carried out in the majority of arthroplasty cases. Several acceptable alternatives exist for tenodesis management. I prefer to secure the biceps into the pectoralis major tendon near the conclusion of the case during wound closure. Tenodesis to the pectoralis major tendon directly after release is also acceptable but may limit the ease of releasing further pectoralis major tendon later in the case if that becomes necessary. Despite the method chosen, the anatomic tension of the biceps tendon is restored during tenodesis to prevent postoperative pain or deformity. If the surgeon elects to perform tenodesis of the long head of the biceps tendon at the conclusion of the case, this is accomplished with the repair of the pectoralis major tendon using two high-tensile sutures and incorporating the long head of the biceps tendon within the repair of the pectoralis major tendon. The borders of the subscapularis tendon are now clearly defined, including the open rotator interval superiorly, the released biceps tendon laterally, and the anterior humeral circumflex vessels inferiorly. With the subscapularis borders clearly defined, attention is turned toward the release of the subscapularis tendon.

Subscapularis management is critical for a successful outcome following an anatomic total shoulder replacement. Failure of subscapularis repair represents one of the most common causes of early failure after anatomic
arthroplasty.³ Subscapularis management should not solely be considered the method of tendon release, but also the management of the tendon during the surgical procedure as well as the meticulous nature of repair during the closure. For example, overaggressive mobilization during glenoid-sided releases can result in denervation by disruption of the upper and lower subscapular nerves as they enter the dorsal surface of the subscapularis medially. Additionally, the method of repair may be at least as important as the type of release performed.

Three primary options are available for the release of the tendon. In the “peel” techniques, the subscapularis is removed subperiosteally and repaired back to the lesser tuberosity with drill holes through bone. In the “tenotomy” technique, the tendon is split vertically, approximately 1 cm medial to the lesser tuberosity attachment, leaving adequate tendon laterally for tendon-to-tendon repair. In the “osteotomy” techniques, the tendon is removed by performing an osteotomy with a small portion of the lesser tuberosity still attached to the subscapularis tendon, which is then reattached to the humerus using one of a variety of techniques. Controversy exists as to which method is superior, and all three methods have shown good outcomes in the literature.³,⁴ None of the methods have shown conclusive superiority, and selection of the approach is based primarily on surgeon preference. The following text focuses on my preferred method of subperiosteal peeling of the tendon from the lesser tuberosity; however, we have included specific techniques of the tenotomy and the osteotomy in the video library.

The subperiosteal subscapularis peel provides several advantages. In patients with severe internal rotation contracture, the tendon is released laterally and repaired along the humeral neck, in a slightly more medial position. Each 1 cm of medialization provides approximately 15° of increased external rotation.¹ The peel, unlike the osteotomy, does not disrupt the existing proximal humeral osseous anatomy. Furthermore, repair of the peel is performed with multiple transosseous sutures, which provide a reliable postoperative construct. Performing the subscapularis release with the arm in an adducted and slightly externally rotated position provides protection of the axillary nerve. Increasing the abduction of the arm moves the axillary nerve progressively more laterally, increasing its risk for injury. The rotator interval is released medially to the anterosuperior glenoid. From the window of the rotator interval, the superior subscapularis attachment to the lesser tuberosity is identified and released with a #10 blade (FIGURE 13.7). Care is taken not to leave any tendon attachment laterally, which allows for maximum tendon excursion when later repaired. The upper two-thirds, or tendinous portion, of the tendon is released with a knife. The lower one-third, or muscular portion, is released with a needle tip electrocautery, directing the needle tip between the previously ligated anterior humeral circumflex vessels. The dissection is continued distally in a subperiosteal fashion until encountering the upper borders of the latissimus dorsi tendon (FIGURE 13.8). The latissimus dorsi tendon serves as an excellent landmark for the inferior extent of the dissection, particularly in patients with extensive glenohumeral joint contracture. Multiple #2 Ethibond stay sutures are placed in the released subscapularis tendon to facilitate retraction throughout the case and assist in later repair of the tendon. Attention is now turned toward the remaining humeral releases and exposure.

The humeral release is continued from the inferior extent of the subscapularis release. The arm should remain in a fully adducted position. Progressive external rotation of the arm combined with gentle flexion allows for the release of the humeral attachments of the inferior glenohumeral ligaments.⁵ Subperiosteal dissection using a needle tip electrocautery combined with adduction, external rotation, and gentle flexion significantly facilitates the protection of the axillary nerve. The inferior
glenohumeral ligaments are released posteriorly beyond the 6 o’clock position to about the 7 o’clock position.

The humeral head is now dislocated using a Darrach retractor to lever the head while externally rotating and extending the arm. If present, a self-retaining deltoid retractor should be removed to prevent traction injury to the musculocutaneous nerve. A posterior humeral head retractor is placed. Removal of all humeral head osteophytes facilitates exposure of the true anatomic humeral neck. Completely dislocate the humeral head by levering forward with the posterior humeral head retractor as the arm is placed into full extension with adduction and external rotation. If a Mayo stand is being used to support the arm, lowering the Mayo stand allows the arm to come into full extension and adduction. In this position, the margins of the articular surface should be entirely visualized (FIGURE 13.9). Visualization of the articular margin is critical for performing humeral osteotomy and avoiding complications.⁶ Landmarks to recognize should include the following: the superolateral margin of the articular surface adjacent to the greater tuberosity and rotator cuff insertion, the posterior rotator cuff attachment, the bare area of the humerus, and the inferomedial margin where the articular surface exits at the medial calcar. The above landmarks are essential for the humeral osteotomy, and if not fully visualized, the surgeon should retrace the humeral releases until achieving adequate visualization.