Chapter 3 Instability

133

CHAPTER 3 | Instability

FIGURE 3-4  Left shoulder, anterosuperolateral viewing portal. Measuring glenoid bone loss. A: A calibrated probe introduced from a posterior portal marks the distance from the glenoid bare spot to the posterior rim. In this case, the distance is ~12 mm. B: The probe is used to measure the distance from the anterior glenoid rim to the glenoid bare spot. In this case, the distance is 6 mm. Thus, there is 6 mm of bone loss anteriorly or 25% loss of the inferior glenoid diameter. G, glenoid; H, humeral head.

Surgical Technique of Congruent-Arc Latarjet Reconstruction We call our surgical technique the congruent-arc technique because we place the coracoid graft in an orientation such that the arc of its inferior surface is a congruent extension to the glenoid articular arc. This requires that we rotate the coracoid graft 90° about its long axis prior to fixation to the anterior glenoid neck. We always perform diagnostic arthroscopy just prior to the Latarjet in order to accurately measure the amount of glenoid bone loss, to assess the Hill-Sachs lesion, and also to evaluate the joint for additional pathology, particularly SLAP lesions. We have found a 64% incidence of SLAP lesions in our patients who are undergoing Latarjet reconstruction. 1 In these cases, we perform an arthroscopic SLAP repair with the patient in the lateral decubitus position. Then, we turn the patient supine and adjust the table to a modified beach- chair position, then re-prep and redrape for the open Latarjet. Coracoid Osteotomy In performing the congruent-arc Latarjet, a standard delto- pectoral incision is used. The cephalic vein is preserved and retracted laterally with the deltoid muscle. The coracoid is exposed from its tip to the insertion of the coracoclavicular ligaments at the base of the coracoid. The coracoacromial ligament is sharply dissected from the lateral aspect of the coracoid, and the pectoralis minor tendon insertion on the medial side of the coracoid is also sharply dissected from the bone (Fig. 3-5). The medial surface of the coracoid, from which the pectoralis minor is detached, is the surface that will later be in contact with the anterior glenoid neck when the graft is secured by screws.

For the coracoid osteotomy, two options are avail- able. Option 1 involves the use of an osteotome to create the osteotomy (Fig. 3-6A). We believe that an osteotome should be used only in thin patients. In a muscular patient with a large deltoid and pectoralis major, the bulk of these

Video 3-2

FIGURE 3-5  In preparation for coracoid osteotomy, the pectoralis minor tendon is sharply dissected off the medial edge of the coracoid.