Multidirectional Instability: Open Capsular Shift

Christopher S. Ahmad

William N. Levine

INDICATIONS

Surgical intervention is considered in the management of multidirectional shoulder instability (MDI) if symptoms persist despite a sufficient trial of nonoperative management.¹^,² Numerous surgical techniques have been used in the treatment of MDI, including capsular shift, capsular plication, rotator interval closure, thermal capsulorrhaphy, labral repair, glenoid osteotomy, and capsular allograft reconstruction, with both open and arthroscopic techniques.¹^,² Despite the breadth of operative techniques, controversy persists as to what constitutes optimal surgical management. Historically, the open capsular shift, originally described by Neer in 1980, was widely considered as the gold standard.³^, ⁴ ^and ⁵ However, current data suggest that arthroscopic techniques are more widespread in today’s operative landscape.¹^,³

No codified treatment algorithm for the surgical treatment of MDI exists. Rather, the treatment selected must be individualized and based on a multitude of factors, including the relevant pathoanatomy, the patient’s goals, and the surgeon’s experience. Additionally, for any treatment to be effective, the same principles of instability repair must be obeyed, with the correction of all pathology at the time of surgery.⁶

The open capsular shift, which decreases capsular volume and reestablishes tension of the glenohumeral ligaments, should be given particular consideration in situations where tissue quality is significantly compromised.⁷ These situations include revision surgery after failed arthroscopic treatment, cases in which there is significant capsular redundancy or capsular rupture, and cases in which there is a humeral avulsion of the inferior glenohumeral ligament. Additionally, a lower threshold can be used to treat collision athletes via open technique.⁷

CONTRAINDICATIONS

Surgical management of MDI is contraindicated or, at the least, should be used with caution, in certain patient populations. Deliberate or voluntary dislocation is an absolute contraindication to surgery.⁸ Additionally, surgical treatment should be used cautiously in patients with psychiatric pathology and/or young, immature patients who may have difficulty adhering to a rigorous pre- and postoperative treatment course and the ensuing rehabilitation.³ The failure of multiple previous open stabilization procedures is also a relative contraindication for additional surgical management, given the decreased chance of treatment success.⁶

PREOPERATIVE PREPARATION

Patients with shoulder instability are often lumped into two separate groups, atraumatic multidirectional instability and traumatic unidirectional instability. However, in reality, shoulder instability is not binary and instead exists along a spectrum between these two extremes. To best understand an individual patient’s pathology and provide the appropriate treatment plan, a thorough assessment, including a comprehensive patient history, physical examination, and review of the diagnostic imaging, should be performed.

History

The patient’s history should include a thorough evaluation of the presenting symptoms, which frequently consist of a combination of instability events and pain. Relevant information includes the age of onset, the number of occurrences, and the direction—anterior, inferior, posterior, bidirectional, or multidirectional—of instability events. Additional information includes the magnitude of events (subluxation vs dislocation) and the origin of instability events—atraumatic, repetitive microtraumatic, or traumatic. Frequently, patients with MDI experience instability events that occur without trauma and, unlike patients with trauma-initiated instability events, consist of recurrent subluxations, not frank dislocations.⁹^,¹⁰ The occurrence of instability episodes with progressively less trauma may be an indication of increased joint laxity or attritional bone loss.¹¹^,¹² It is also important to identify patients who may be voluntarily dislocating their shoulder irrespective of the assumed primary or secondary gain.

Ligamentous laxity should be assessed via patient history, as well. Patients should be asked about a family history of dislocations, as well as medical conditions that result in ligamentous laxity, such as Ehlers-Danlos syndrome or Marfan syndrome. Additionally, bilateral symptoms, subjective instability with activities of daily living, and the sensation of instability with the arm in an adducted position may also be present in the ligamentously lax patient.¹¹^,¹³

Inquiry regarding the patient’s activity level and treatment goals is also important. For example, high-level throwing athletes may benefit from a more limited, motion-preserving treatment, even if it is accompanied by a slightly higher risk for recurrence. Conversely, patients without such athletic ambitions may benefit from a more robust treatment, even if it is accompanied by a slight decrease in range of motion.

Physical Examination

In the assessment of MDI, the physical examination should include inspection, palpation, range-of-motion testing, strength testing, and neurovascular assessment. In addition to these standard components, there are a variety of instability-specific test maneuvers that should be performed. The unaffected shoulder should also be assessed to function as an internal control.

Anterior instability can be assessed with several maneuvers. The load and shift test is performed by manually applying an anteriorly directed force to the humeral head and assessing the magnitude of translation relative to the glenoid. The apprehension test is performed by bringing the extremity into abduction and external rotation, which, if positive, will cause the patient to experience a sense of shoulder instability or anxiety. Following this maneuver, the relocation test is then performed by applying a posteriorly directed force onto the humeral head, which may decrease the sense of instability. Similar in nature, the anterior release test is performed by bringing the extremity into abduction and external rotation, this time with the examiner’s hand on the humeral head applying a posterior force. The test is positive if release of the examiner’s hand creates a sense of instability.

Similarly, there are several examination maneuvers that specifically assess posterior instability. The load and shift test can be performed, this time with a posteriorly directed force. The Jerk test is performed with the extremity in a position of flexion, adduction, and internal rotation followed by application of an axial load to the humerus. The Kim test is performed by positioning the extremity at 90° of abduction while simultaneously flexing the shoulder to approximately 45° and creating a posteroinferior moment on the humeral head via force applied to the elbow. The Jerk and Kim tests are considered positive if they produce pain and/or subluxation.

Hyperlaxity can also be assessed in several ways. A positive sulcus sign and Gagey hyperabduction test are indicative of inferior shoulder hyperlaxity.¹¹^,¹⁴ The former is performed by applying an inferiorly directed force on an adducted arm and examining for the development of a sulcus between the humeral head and the edge of the acromion. A positive test in external rotation is indicative of a pathologic rotator interval. The Gagey hyperabduction test is performed by assessing the magnitude of passive abduction, with greater than 105° considered positive. Additionally, hypermobility should be assessed via calculation of a Beighton score, which assesses hypermobility of the spine, knee, elbow, wrist, and 5th digit, and is considered diagnostic of ligamentous laxity with a score greater than 4 out of 9.¹¹^,¹⁵

Imaging Modalities

Standard radiographs, including Grashey (true anteroposterior), axillary, and scapular Y views, should be obtained in the assessment of a patient with MDI. Frequently, radiographs do not demonstrate any osseous abnormalities. However, bony defects, such as Bankart or Hill-Sachs lesions, are sometimes seen and can be indicative of previous instability events.

If present, bony abnormalities, particularly glenoid bone loss and Hill-Sachs lesions, can be further assessed via computed tomography (CT). The extent of bone loss may be underestimated on plain radiographs alone.¹⁶ Therefore, CT, particularly with the inclusion of 3-dimensional (3D) reconstructions, is the preferred modality by which bone loss is assessed.

Magnetic resonance imaging (MRI) can be included for better assessment of soft tissue anatomy, including capsuloligamentous structures, chondral surfaces, the glenoid labrum, and the rotator cuff. Magnetic resonance arthrography is particularly useful in the assessment of capsular volume, with a patulous inferior capsule commonly seen.¹⁷^,¹⁸ Newer software programs allow for 3D reconstructions on MRI as well, which is advantageous to avoid the irradiation incurred from CT.

OPEN CAPSULAR SHIFT TECHNIQUE

The patient is placed in the beach chair position. Prior to incision, an examination under anesthesia is performed, including range-of-motion testing, load and shift testing, and examination of the sulcus sign. An articulating arm holder can be used throughout the case.

A standard deltopectoral approach is used for this procedure. An 8- to 10-cm incision is made from the inferior aspect of the coracoid to the top of the anterior axillary fold. After the placement of two self-retaining Gelpi retractors, dissection continues to the deltopectoral fascia. The deltopectoral interval is identified and developed, with the cephalic vein taken laterally. Subsequently, the clavipectoral fascia is incised just lateral to the short head of the biceps and deep retractors are placed under the conjoint tendon medially and the deltoid laterally.

Subsequently, the subscapularis is visualized, tenotomized, and separated from the underlying capsule. The subscapularis tenotomy is initiated with electrocautery approximately 1 cm medial to the lesser tuberosity (Figure 42-1). During this step, one must take care to avoid incising the underlying joint capsule. Following a partial-thickness incision, the now freed subscapularis tendon edges are tagged at their superiormost aspect with #2, nonabsorbable sutures (Figure 42-2). This step facilitates anatomic repair at the conclusion of the procedure. After completion of the tenotomy, the subscapularis is then dissected gently from the underlying capsule using Mayo scissors (Figure 42-3). Achieving a distinct separation of the two layers is critical, and sufficient care must be taken to achieve this goal. Following the separation of the subscapularis and underlying capsule, three #0 nonabsorbable sutures are placed superiorly to inferiorly in the lateral edge of the tendon (Figure 42-4).

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