Arthroscopic Anterior Shoulder Instability in the Athlete

Arthroscopic Anterior Shoulder Instability in the Athlete

Lauren A. Szolomayer, MD and Robert Arciero, MD

Anterior shoulder instability and recurrent anterior shoulder dislocations are associated with limitations in sports and development of early glenohumeral arthritis.^1,2 After a dislocation in young patients, instability recurrence rate has been reported to be up to 90% with nonoperative treatment.³ Many techniques exist for treatment of acute and chronic shoulder instability. Open Bankart has been the traditional approach for treatment of labral tears and instability of the shoulder. As treatment transitioned to arthroscopic techniques, the arthroscopic Bankart repair was found to significantly reduce the recurrence rate in young athletes who sustained an acute, initial anterior dislocation of the shoulder.⁴ Arthroscopic Bankart has increased in popularity; however, recurrence can range from 13% to 35% in reported studies.^5–7 Techniques for repair are dependent on the direction and degree of instability, the patient’s desired activity, bone loss on the glenoid or humeral head, and prior surgeries. Although much of the literature has focused on recurrent instability as a key outcome, perhaps equally important is the patient’s ability to return to the same level of sport or unrestricted activity. In a review of primary shoulder dislocations in West Point Cadets, the common concomitant injuries were defined including Bankart lesion in 63 out of 65 patients, type 2 superior labrum anterior and posterior tears, capsular tears, humeral avulsion of the glenohumeral ligament lesion, and 22% with a glenoid rim avulsion or “Bony Bankart.”³

The following chapter will cover the indications and contraindications for arthroscopic Bankart repair; management of soft-tissue and bony Bankart, Hill-Sachs, anterior labroligamentous periosteal sleeve avulsion (ALPSA), and glenolabral articular disruption (GLAD) lesions; outcomes; common complications; and the senior author’s preferred technique for performing an arthroscopic Bankart repair.

INDICATIONS AND CONTRAINDICATIONS FOR BANKART REPAIR

Evaluation of the athlete’s shoulder begins with a thorough history. It is important to assess when and if initial traumatic dislocation occurred, the number of dislocation or subluxation events, activity level, and level of sports participation. In addition, prior treatment, if any, should be assessed, including physical therapy and surgical treatment. The evaluation and recommendations for arthroscopic treatment of Bankart also involves ruling out bone loss. Significant bone loss is rare in a first-time dislocator. If the patient’s history includes multiple dislocations, dislocation during sleep, seizure or revision surgery, or exam finding of apprehension at a low angle of abduction, all are indicators of potential bone loss both on the glenoid and humeral side. Adolescents (ages 10 to 19 years) and patients who experience multiple shoulder dislocations are both independent risk factors for development of an off-track Hill-Sachs lesion that may require addition of a remplissage accompanying the arthroscopic Bankart.⁸

CASE EXAMPLE

A 21-year-old male college football player sustained his first dislocation in preseason and was treated with rehabilitation and a brace. He returns to practice in 7 days without apprehension signs. The initial magnetic resonance imaging in Figure 8-1 shows a typical Bankart lesion that would require 2 or 3 anchors for arthroscopic repair.

Figure 8-1. Magnetic resonance imaging after a first-time dislocation with an anterior labrum tear and posterior humeral head edema.

Figure 8-2. Second magnetic resonance imaging with a 300-degree labral tear.

After undergoing a rapid return to sport, he is able to play in 5 games with 3 other subluxation events. During his sixth game he undergoes a major subluxation event (Figure 8-2). The result is a 300-degree tear that subsequently required 6 double-loaded anchors and arthroscopic repair. Figure 8-3 shows the arthroscopic images of the 300-degree labral tear after multiple instability events.

PHYSICAL EXAM

A detailed description of the physical exam is provided in Chapter 3 and important aspects are emphasized in Table 8-1. The apprehension test, with the patient feeling uncomfortable or that he or she may dislocate versus just pain, should be tested in the abducted and externally rotated (ABER) position, which is generally the position of maximum instability. The load and shift may be applied in the ABER position as well, with load applied along the axis of the humerus and then translating the humerus anteriorly over the glenoid. This is graded on a scale of 0 to 3+ with no anterior translation, 1+ an anterior shift to the glenoid rim, 2+ a dislocated humerus but reduces spontaneously, and 3+ an anterior shift to dislocation, which requires manual reduction. Typically a 3+ indicates the presence of bone loss on either the humeral or glenoid side. Other tests may be applied to rule out multidirectional or posterior instability.

Figure 8-3. Arthroscopic images of a 300-degree labral tear after multiple instability events.

Table 8-1. Physical Exam Findings—Special Tests

Abbreviation: ABER, abducted and externally rotated.

IMAGING

Radiographs obtained at the initial evaluation should include a true anteroposterior (Grashey), scapular-Y, and West Point views to evaluate for bone loss. A Hill-Sachs lesion may be identified if present. Magnetic resonance imaging is indicated in all young dislocators and is the modality of choice for evaluating a labral tear. Adding contrast to the joint during imaging via magnetic resonance arthrogram can increase the sensitivity and specificity for identifying labral tears, particularly in the recurrent setting after prior repair. A computed tomography scan is indicated when bone loss is suspected based on radiographs or number and ease of dislocation events and any of the risk factors discussed earlier.

MANAGEMENT

The available evidence supports operative stabilization for primary anterior shoulder dislocation in young patients participating in highly demanding physical sports.9–11 Indications for arthroscopic stabilization include a first-time dislocation in those younger than 22 years, overhead athletes, less than 15% bone loss on the glenoid, on-track bipolar defects, and panlabral injuries. For other athletes, and those who may be in-season and unable or unwilling to take time off for surgery, it is reasonable to treat with conservative management. A shoulder stabilization brace may be donned in the acute setting immediately post-dislocation for comfort and in settings in which high-level, nonthrowing athletes require immediate return to play. Nonoperative treatment should include physical therapy for periscapular and rotator cuff strengthening and modalities as needed after a brief period of immobilization if frank dislocation has occurred.

TECHNIQUE FOR BANKART REPAIR

The patient is brought to the operating room, where the anesthesia team typically places a peripheral nerve block before induction of anesthesia. This helps with postoperative pain control and decreased anesthetic requirements during the procedure. General anesthesia without complete relaxation is generally appropriate.

The affected and contralateral shoulders should be examined under anesthesia before positioning. This is a critical component to evaluation of the patient to accurately characterize the direction and degree of instability while the patient is relaxed (Figure 8-4).

Figure 8-4. Exam under anesthesia, showing anterior translation (3+ load and shift).

The authors’ preferred technique for arthroscopic stabilization is in the lateral decubitus position with a beanbag positioner and the arm in a weighted traction setup (Figures 8-5 and 8-6).

This position has shown a decreased risk of instability recurrence than when performed in the beach chair position.¹² This position also allows for ease with mobilization of the Bankart, re-tensioning of the inferior glenohumeral ligament (IGHL), access to the 6’oclock position on the glenoid face, and aids in addressing capsular redundancy. A weighted traction setup or arm positioner may be used, with a sterile “bump” to aid in abduction of the arm away from the body and to create increased space in the glenohumeral joint (Figure 8-7).

Typically 3 to 4 portals are used (Figure 8-8). Portals will include a posterior portal marked just off the posterolateral edge of the acromion and 2 cm distal, which allows for better visualization of the anterior inferior glenoid; 8.5 mm cannulas are inserted in each portal to ease passage of instruments. Once the glenohumeral joint is entered, an anterior-superior portal is then created within the rotator interval behind the biceps tendon. This portal is created in a higher position than a standard anterior portal to allow visualization and room for a second, anterior inferior portal as a working portal, without convergence of these 2 portals. Additional percutaneous portals for anchor placement can be created if needed.

A diagnostic scope is performed visualizing the glenoid and humeral cartilage surfaces, the biceps insertion, the superior labrum, which is probed, the anterior inferior labrum, presence of a humeral avulsion of the glenohumeral ligament lesion, subscapularis tendon and its insertion, and rotator cuff insertion. Posteriorly the bare spot and Hill Sachs lesion if present may be visualized prior to visualizing the posterior aspect of the axillary pouch and the posterior labrum.