Glenoid Exposure During Shoulder Replacement

Deltopectoral Approach 

Exposure of the glenoid begins with an extensile deltopectoral approach. The incision begins just medial to the coracoid and continues to the area of the insertion of the deltoid. The skin is incised sharply and dissection is continued with the use of a sharp electrocautery device. Retraction is performed with sharp Gelpi retractors using a lifting motion to identify the dissection planes. Once the subcutaneous fat has been incised, the underlying pectoralis major and deltoid muscle can be appreciated. The medial border of the deltoid extends medial to the tip of the coracoid overlying the pectoralis major. The fatty triangle at the most proximal portion of the incision delineates the interval between the deltoid and pectoralis major. A straight Adson is used to define the interval and pierce the superficial fascia. Blunt dissection is utilized to mobilize the interval. The cephalic vein is retracted laterally to minimize bleeding from venous branches. The clavipectoral fascia is pierced with a straight Adson and the fascia is opened. The conjoint tendon is identified and can be retracted medially. The subdeltoid space is developed, extending from its insertion to underneath the acromion, allowing the placement of a deltoid retractor.

Release of the superior 2 cm of the pectoralis major adds significantly to the exposure of the glenoid (Fig. 1). Additional pectoralis major can be released without significant morbidity if it is required to improve visualization.

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Figure 1. Release of the sternal head of the pectoralis major insertion to the humerus is very helpful for exposure of both the humerus and the glenoid. We recommend releasing approximately 3 to 4 cm of the upper portion of the pectoralis major insertion. (Color version of figure is available online.)

The coracoacromial ligament is then identified with the use of a lap pad sweeping off subcutaneous fat. The ligament is then sharply released with the use of electrocautery. This allows improved visualization of the rotator interval and the upper border of the subscapularis muscle.

Humeral Exposure 

The long head of the biceps is identified in the biceps groove and is tenotomized as proximally as possible (Fig. 2). The tendon is identified and the transverse humeral ligament is released. Tenodesis of the biceps tendon is performed only in young patients in whom a cosmetic deficit or spasticity in the early postoperative period is a concern.

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Figure 2. The bicipital groove is exposed by releasing the transverse humeral ligament all the way into the rotator interval. The biceps tendon is then delivered out of the groove and tenotomized. Tenotomy of the biceps greatly improves exposure to the humerus for capsular release. (Color version of figure is available online.)

It is important to visualize and identify the superior and inferior border of the subscapularis muscle. The three sisters, the anterior humeral circumflex artery along with two venae comitantes, can be visualized delineating the border between the tendinous and muscular portions of the subscapularis. A large curved osteotome is then used to remove the lesser tuberosity, allowing the subscapularis to be left in continuity1 (Fig. 3). When performing the osteotomy it is preferable to perform it more aggressively. A larger osteotomy results in the removal of more humeral head, leading to improved exposure. Excess osteophyte should be removed from the lesser tuberosity with the use of a bone rongeur to facilitate reattachment of the lesser tuberosity. The tuberosity is then tagged with a suture.

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Figure 3. (A) A lesser tuberosity osteotomy is performed after biceps tenotomy. A curved osteotome is placed into the bicipital groove and approximately a 7- to 10-mm-thick sleeve of bone is osteotomized. (B) This figure depicts the lesser tuberosity after osteotomy. Removal of the 7-mm-thick bone along the anterior–medial edge of the humerus greatly improves the exposure to the glenoid and allows for secure fixation of the subscapularis after placement of the humeral and glenoid components. (Color version of figure is available online.)

The humeral capsular release is performed by first reflecting the capsule inferiorly. Electrocautery is used to release the capsule down the humeral shaft. The release continues inferiorly until the superior 2 cm of the latissimus dorsi is released. The humerus is adducted, flexed, and externally rotated to facilitate the subperiosteal release around the posterior aspect of the humerus.

Glenoid Exposure 

The coracohumeral ligament is then released and the rolled border of the subscapularis is visualized. The middle glenohumeral ligament is bluntly dissected from the subscapularis. They are then incised in a vertical fashion (Fig. 4). Inferiorly the capsule and inferior glenohumeral ligament is identified and bluntly dissected. Once the inferior capsule has been isolated, the axillary nerve can be palpated and protected. The overlying inferior capsule can be safely released once the axillary nerve has been located.

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Figure 4. After humeral releases, glenoid releases are initiated by first removing the coracohumeral ligament. After this, the interval between the subscapularis and the middle glenohumeral ligament is divided. The middle glenohumeral ligament is then sharply incised in a vertical fashion from superior to inferior using Mayo scissors as shown. (Color version of figure is available online.)

Bankart retractors are placed around the glenoid. One retractor is placed posterosuperiorly, one is placed posteroinferiorly, and one is placed anteriorly. The placement of retractors gives excellent visualization of the glenoid (Fig. 5).

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Figure 5. After release of the middle and inferior glenohumeral ligaments, good exposure to the glenoid can be obtained by placing retractors posterior–superior, posterior, and anterior. (Color version of figure is available online.)

Once exposure has been performed, the center of the glenoid is found with a 2 mm drill bit, which is used to sound the glenoid vault (Fig. 6). Only the lateral cortex is perforated and the depth of the vault is measured to ensure adequate bone stock to accommodate the glenoid component.

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Figure 6. Initial placement of the central drill hole as well as the angle of orientation can be tested by using a 2-mm drill bit to “sound” the glenoid vault. The near (lateral) cortex is penetrated by the drill and the far (medial) cortex is not penetrated by the drill but rather palpated to verify the best angle to place the drill into the deepest portion of the glenoid vault. (Color version of figure is available online.)

Repair of Lesser Tuberosity 

Repair of the lesser tuberosity osteotomy is performed with 18-gauge wires. Before the placement of the humeral prosthesis, two drill holes are placed lateral to the bicipital groove. The 18-gauge wires are inserted before the placement of the prosthesis. The wires are then positioned around the prosthesis. The 18-gauge wires are inserted through the inferior aspect of the subscapularis muscle and around the lesser tuberosity. The wires are then tensioned together giving excellent stability and fixation. This allows bony healing of the osteotomy and immediate postoperative motion.