The development of the current designs of reverse total shoulder arthroplasty (RTSA) has changed our approach to the treatment of a wide spectrum of degenerative conditions of the glenohumeral joint, ranging from massive irreparable rotator cuff tears without arthritis to glenohumeral arthritis with an intact rotator cuff (in selected patients) to advanced rotator cuff arthropathy. The availability of augmented glenoid components has further enhanced our ability to treat these conditions. The ability to address glenoid deformity and restore anatomy to a greater degree can be expected to improve implant survival and ultimately improve long-term clinical outcomes. In this chapter, we will focus on the use of an augmented glenoid component to correct significant glenoid deformity in a 77-year-old male with advanced glenohumeral arthritis, an intact but degenerative rotator cuff, and significant asymmetric posterior glenoid erosion consistent with a B2 deformity.

Evaluation of each patient should include a thorough history and physical examination. Previous shoulder surgery should be documented and if available, previous operative reports should be obtained to determine if metallic or non-metallic implants may have been used about the glenoid or proximal humerus.

The physical examination should document both active and passive range of motion. If significant stiffness is present, more extensive releases will be required which should be part of the preoperative planning. Preoperative radiographic examination is essential to understand the nature of the glenoid deformity. We obtain standard radiographs on all patients that include scapular AP with the humerus in internal rotation, scapular AP with the humerus in external rotation, scapular Y view, and a supine axillary view (Figure 51-2). This will provide relevant information about the nature and degree of glenoid deformity. However, experience has shown us that accurate evaluation of the glenoid requires a CT scan with 3D reconstructions. We have found that the CT scan provides important information about the type of glenoid deformity, the degree of glenoid deformity, as well as important information about the glenoid vault and its relationship to the glenoid face. In many shoulders, the glenoid “face anatomy” does not match the “vault anatomy.” This is important information since it will impact the placement of the glenoid component. In addition, we preoperatively plan each case using 3D software that allows us to determine the type of glenoid baseplate necessary and the optimal position for placement. This software requires a preoperative CT scan with a specific protocol so the images can be segmented for use with the planning software. However, it is important to note that even prior to the utilization of the planning software, we obtained a CT scan in every patient undergoing shoulder arthroplasty in order to better understand glenoid anatomy and deformity.

Our description of the operative technique will focus primarily on the glenoid. However, it is essential that the patient be properly positioned on the operating room table so that the upper extremity can be easily and freely mobilized to enhance glenoid exposure. We utilize a beach chair position with the bed elevated approximately 45° to 60°. We utilize a Captain’s Chair so the patient can be properly and securely positioned. A deltopectoral approach is utilized. The subdeltoid space is mobilized and all adhesions are released and continuity with the subacromial space is established. The release of adhesions is important not only for mobilization of the proximal humerus but also for glenoid exposure. The pectoralis major muscle is mobilized followed by the conjoined tendon muscles. Adhesions at the base of the coracoid are released. A biceps tenodesis is performed to the pectoralis major tendon insertion. We utilize a subscapularis tenotomy to gain access to the glenohumeral joint. Lesser tuberosity osteotomy and subscapularis peel are other ways to gain access to the glenohumeral joint and the choice is one of surgeon preference. The subscapularis tendon is tagged with nonabsorbable sutures for retraction and mobilization. The inferior capsule is released posteriorly to maximize mobilization. All humeral head osteophytes are removed so the anatomic neck can be identified. A humeral neck osteotomy is performed at an angle consistent with the
humeral implants being utilized. We prepare the humerus with the arm in extension and external rotation. Sequential reaming and broaching are performed until the desired size implant is determined. We prefer to implant the final humeral stem at this time rather than leave the trial in place. It is important to emphasize that proper preparation of the humerus does have an impact on achieving glenoid exposure. The humeral head resection must be at an adequate level so that sufficient “space” is available for glenoid exposure. In addition, all humeral neck osteophytes should be removed and the inferior capsule released to achieve proper mobilization. These steps are particularly important when augmented glenoid components are used because of the existing glenoid deformity. The most common glenoid deformity is asymmetric posterior erosion which requires a greater exposure with more challenging placement of instruments to prepare the glenoid.