26.1 Introduction

Recurrent anterior shoulder instability can be associated with bony defects of the anterior glenoid, large and engaging Hill–Sachs defects, and insufficient tissue quality of the anterior capsule and the labrum. In those cases, a sole fixation of the capsulolabral complex is related to a high risk for recurrent anterior instability.

Bony augmentation of the anterior glenoid rim using the coracoid process stabilizes the shoulder by enlarging the horizontal glenoid diameter and by the additional sling effect of the attached conjoint tendons ( Fig. 26.1 ).

The principle of the arthroscopic Latarjet procedure is the minimally invasive identification of the coracoid process and a consecutive osteotomy at its base. Using a positioning guide, it is then maneuvered into the joint through a horizontal split of the subscapularis tendon and fixed to the anterior glenoid with two cannulated screws.

26.2 Indications

An arthroscopic Latarjet procedure is indicated for primary and recurrent anterior shoulder instability with the following:

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  Glenoid bone loss greater than 20% of the horizontal diameter.

  
  
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  Large and engaging Hill–Sachs defect.

  
  
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  Combined bony defects of humerus and glenoid.

  
  
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  Irreparable soft-tissue defects of the capsulolabral complex including humeral avulsion of the glenohumeral ligament (HAGL) lesions.

26.3 Contraindications

The arthroscopic Latarjet procedure is contraindicated, in case of the following:

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  Adequate bone stock and soft-tissue quality allowing an arthroscopic Bankart repair.

  
  
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  Adolescent patients or children.

  
  
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  Relevant defects of the subscapularis tendon.

  
  
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  Advanced instability osteoarthritis.

26.4 Preoperative Examination

Patient history may reveal valuable clues about the severity and the risk for recurrence of anterior shoulder instability. If minor trauma causes dislocation of the affected shoulder, bone defects or severe soft-tissue damage should be considered. Recurrent dislocations after previous Bankart repair might not be addressed properly by another refixation of the capsulolabral complex. Contact sports are related to a higher recurrence rate.

Various clinical tests assess anterior shoulder instability. Most commonly, the affected shoulder is brought into an abduction and external rotation position, which causes pain or countermovement in order to avoid dislocation.

For the apprehension test the patient’s shoulder is abducted into different positions and externally rotated, while the examiner applies pressure to the humerus from posterior and observes increasing pain or countermovement.

For the relocation test, the patient’s shoulder is moved into abduction and external rotation in a supine position. If this causes pain, manual pressure is applied to the anterior humerus. Pain relief caused by this maneuver indicates anterior shoulder instability.

Standard anteroposterior and axial radiographs show larger glenoid substance loss and Hill–Sachs defects. Further X-ray techniques assess smaller bone lesions. The West Point view indicates glenoid defects and bone fragments, while the Stryker view projects Hill–Sachs defects.

Soft-tissue structures, cartilage lesions, concomitant lesions of the rotator cuff and the biceps tendon, as well as bone defects are revealed on MRI scans.

Bone loss and bone defects are ideally identified on CT scans. 3D reconstructions of the glenoid with a subtracted humeral head facilitate quantification and localization of glenoid defects especially when the affected glenoid is compared to the healthy contralateral side ( Fig. 26.2 ).

26.5 Surgical Technique

The procedure is processed in the beach-chair position using an arm holder (e.g., Spider, Smith & Nephew). The arthroscopic Latarjet requires ideal anesthesia in combination with a nerve block of the brachial plexus. A mean arterial blood pressure between 60 and 65 mm Hg should be maintained during the coracoid transfer to avoid bleeding and poor visualization. To prevent intraoperative hypoxia, a continuous regional oximetry of the forehead should be applied (e.g., INVOS, Medtronic).

Besides a standard burr and a shaver, a radiofrequency device is mandatory (e.g., VAPR, DePuy Mitek). Laurent Lafosse has developed specific instruments for the arthroscopic Latarjet. To date, they are exclusively available from one manufacturer (DePuy Mitek; Fig. 26.3 ). Fixation of the coracoid process to the anterior glenoid is achieved through cannulated screws and sleeves (top hats).

After identification and marking of anatomical structures ( Fig. 26.4 ), diagnostic shoulder arthroscopy and assessment of an engaging Hill–Sachs defect in abduction and external rotation are carried out using the posterior portal (A). Anterior labrum, capsule, and ligaments are checked for their tissue quality.

If a transfer of the coracoid process is indicated, the insufficient labrum, the medial glenohumeral ligament, and the anterior capsule are resected through an anteromedial portal (E) to visualize the anterior glenoid rim and the subscapularis muscle fibers. Bone fragments and remnants of previous Bankart repairs (sutures and anchors) have to be removed with a shaver, an elevator, or a rongeur.

The next steps are opening of the rotator interval, visualization the coracoid process by separating the coracoacromial ligament, and identification the conjoint tendons ( Fig. 26.5 ).

After placing the arthroscope into the anterolateral portal, the extent of the anterior glenoid defect becomes more evident. The glenoid neck is debrided and a bone bed is prepared with a burr or a rasp through an anteromedial portal (E).

After releasing the superior and lateral coracoid process, the axillary nerve can be identified with the help of careful medial preparation between the conjoint tendons and the subscapularis muscle. The conjoint tendons are also released anteriorly ( Fig. 26.6 ).

The arthroscope is consecutively switched to the anteromedial portal (E). The assistant retracts the deltoid muscle cranially with a switching stick introduced through the anterolateral portal (D). After generating a medial portal superior to the coracoid process (H), the pectoralis minor tendon is detached from its insertion on the medial border of the coracoid and the conjoint tendons. Injury to the brachial plexus and to the musculocutaneous nerve has to be avoided carefully during the dissection.

Afterward, two parallel K-wires are drilled centrally through the coracoid using a jig. To evaluate the correct position of the two K-wires, the arthroscope is introduced through the supracoracoid portal. If the K-wires are both central and in the correct longitudinal coracoid axis, two holes are created using a 3.2-mm cannulated drill. After drilling, a tap is used to create threads before two sleeves (top hats) are inserted to support the threads ( Fig. 26.7 ).

As a next step, the subscapularis muscle and tendon are identified utilizing a deep anterolateral portal (J). The last portal is a deep anteromedial portal, whose localization is crucial for subsequent fixation of the coracoid process. Thus, the portal needs to be in line with the glenoid surface.

In order to identify the correct level of the horizontal subscapularis split, a switching stick is inserted via the posterior portal (A) and penetrated through the subscapularis tendon under arthroscopic control right at the position of the glenoid defect (the 3 to 5 o’clock position). A radiofrequency device is inserted through the deep anteromedial portal to split the subscapularis tendon beginning at the position of the penetrated switching stick. At least one-third of the subscapularis tendon should remain superior to the split. The split should rather be extended medially into the muscle fibers than laterally, where the tendinous part should be preserved. Medially, the axillary nerve needs to be identified repeatedly in order to protect it. The size of the split needs to be large enough to provide a good view on the anterior glenoid through the deep anterolateral portal (J) and sufficient approach path for the coracoid process ( Fig. 26.8 ).

The inferior breaking point of the coracoid osteotomy is determined by milling the inferior cortex of the coracoid. For this procedure, a burr is inserted through the anterolateral portal (D) and visualized via the anteromedial portal (E). After the inferior cortex is weakened, the osteotomy is carried out with a curved chisel inserted through the supracoracoid portal (H; Fig. 26.9 ).

After completion of the osteotomy, the positioning device is introduced through the deep anteromedial portal (E) and the coracoid is fixed to the device with two screws. The inferior cortex of the coracoid is decorticated and shaped to fit onto the glenoid defect using a burr or a rasp via the anterolateral portal (D; Fig. 26.10 ).

The positioning device in the inferior anteromedial portal (I) is consecutively used to maneuver the coracoid through the subscapularis split and to put it onto the glenoid defect. The switching in the posterior portal (A) is used as a retractor for this step. The ideal position of the coracoid on the anterior glenoid is between the 3 and 5 o’clock positions. The graft needs to be flush with the glenoid defect and the joint level. The coracoid is then temporarily fixed with two long K-wires that pass the positioning device, the coracoid, and the glenoid in the correct level of anteversion (~30 degrees) before they penetrate the posterior skin.

The cannulated drill is used to create two drill holes. The length of the drill tunnels can be read from the drill. Afterward, two cannulated screws are tightened alternately, while the compression of the coracoid to the glenoid is checked arthroscopically via the deep anterolateral portal ( Fig. 26.11 ).

The position of the graft is finally visualized from different perspectives in order to avoid parallax errors ( Fig. 26.12 ). A lateral overhang of the graft can be reduced with a burr.