31.1 Goals of Procedure

The main purpose of arthroscopic posterior stabilization is to prevent recurrent macro (dislocation) or micro (recurrent posterior subluxation [RPS]) posterior instability of the glenohumeral joint. Traditional techniques focused on open capsular plication with labrum repair, bone block, or wedge osteotomy to prevent recurrent posterior instability. Evolving techniques have allowed for better access to the glenohumeral joint with an arthroscopic approach with accompanying superior clinical outcomes in recent years. The ultimate goal of arthroscopic management is to restore normal glenohumeral mechanics, prevent recurrent instability or subluxation, and allow for return to normal physiologic function of the joint and athletic participation. The arthroscopic method is also aimed at improving short-term range-of-motion goals and preventing disruption of the deltoid or scapular musculature, which can delay postoperative rehabilitation and may accompany an open technique.

31.2 Advantages

The arthroscopic approach to posterior stabilization has the advantage of treating a wide array of pathology. With open techniques, anterior pathology of the shoulder (labrum tearing, subscapularis disruption) in addition to superior pathology (supraspinatus, biceps tendon, and superior labrum tearing) is near impossible to address through the same exposure. The arthroscopic approach allows for clear visualization of the entire labrum, rotator cuff, and other pain-generating pathology around the glenohumeral joint, which also allows for adequate treatment. In addition, arthroscopic management of posterior instability allows for complete labrum repair, in addition to capsular plication in an “around the world” fashion. Recent studies evaluating postoperative outcomes of the arthroscopic approach have also surpassed those of open techniques, making the arthroscopic modality the current standard of care for the majority of patients.

31.3 Indications

Patients are candidates for arthroscopic posterior stabilization if they present with prior episodes of posterior dislocation or RPS of the glenohumeral joint that has not responded favorably to conservative management. Patients with macroinstability or joint dislocation may have accompanying osseous pathology (reverse Hill–Sachs lesion, reverse osseous Bankart lesion) that can accompany the soft-tissue pathology seen in patients with RPS (posterior labrum tear, Kim’s lesion, capsular tearing, or patulous capsule). Patients who have suffered an initial posterior dislocation of the shoulder are initially closed reduced and assessed for instability. Once a pain-free shoulder with full range of motion is restored, patients are gradually returned to regular activity. If resultant instability or pain persists and physical therapy is not ameliorative, then the patient is counseled regarding surgical intervention. Patients with RPS may not report an initial traumatic event, however, and may have a more insidious course with deep-seated shoulder pain, reduced athletic participation (difficulty throwing a long ball or loss of velocity), and pain with cross-body and adducted shoulder movements. An initial course of physical therapy can be initiated in addition to a throwing regimen for overhead throwing athletes. If pain subsides, gradual return to play is begun and the patient can be assessed for recurrence of symptoms. If pain or subluxation returns, an MRA can be obtained to confirm the diagnosis. Once confirmed, the specific anatomical considerations can be evaluated and the patient can be counseled regarding the need for surgical intervention. Our primary indications for surgery are the following:

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  History consistent with prior dislocation or RPS (as detailed earlier).

  
  
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  Physical examination that is positive for any or all of the following:

  
  
  
  
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    Kim’s test.

    
    
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    “Jerk” test.

    
    
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    Positive posterior load and shift test.

    
    
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    Pain with cross-body and adduction with reproduction of symptoms.

  
  
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  Diagnostic imaging (MRA) demonstrating the following:

  
  
  
  
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    Patulous posterior capsule.

    
    
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    Posterior labral tear or concealed crack (“Kim’s” lesion).

    
    
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    Reverse Hill–Sachs impaction fracture.

    
    
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    Relative increase in glenoid retroversion with hypoplastic labrum.

  
  
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  Patients who failed conservative treatment with a stretching and strengthening rotator cuff rehabilitation program.

31.4 Contraindications

As arthroscopic techniques have evolved, so have the relative contraindications to an arthroscopic approach. Contraindications to arthroscopic surgery may include large glenoid (>25%) or reverse Hill–Sachs (>30%) lesions that may be better managed with an open bone grafting technique, capsular tearing with loss of capsular tissue (from prior surgery or thermal modification), excessive glenoid retroversion (type C glenoid), significant osteoarthritis or chondral erosion, neuromuscular abnormality resulting in motor deficit, and patients who have failed a prior arthroscopic procedure (relative contraindication). Any patient who is unable to comply with a postoperative regimen that consists of a brief period of immobilization followed by a structured therapy protocol is not a suitable candidate for surgical intervention.

31.5 Preoperative Preparation/Positioning

31.5.1 Preoperative Preparation

Prior to surgery, the MRA is evaluated for degree of glenoid retroversion, significance of any osseous pathology, and the degree of labrum pathology ( Fig. 31.1 ). Routine radiographs (anteroposterior [AP], scapular Y, and axillary views) are also typically obtained prior to MRA to exclude the presence of fracture, subluxation, or frank dislocation. Understanding the needs of each patient is critical to achieving success with this technique. For instance, patients who engage in high-risk contact sports are more likely to have significant labral pathology and require added capsular plication. Patients who are overhead throwing athletes will have difficulty returning to sports if excessive plication is performed causing a decrease in range of motion and capsular tightness. Patients are given information regarding the risks of surgery, which may include stiffness, infection, neurovascular injury, and recurrence of instability. On the date of the surgery, we routinely use an interscalene nerve block with general anesthesia for both intraoperative muscle relaxation and postoperative pain control.

31.5.2 Positioning

We prefer a lateral decubitus position, but recognize that a beach-chair position can be utilized for this technique. The lateral decubitus position offers excellent access to the posterior joint and capsule without the use of accessory traction by an assistant. A beanbag positioner is typically used with an axillary roll to protect the nonoperative extremity. The down leg is padded over the peroneal nerve, fibular head, and lateral malleolus. The operative arm is placed in 10 to 15 lb of balanced arm traction in 45 degrees of abduction and 20 degrees of forward flexion ( Fig. 31.2 ). When the posterior, inferior aspect of the labrum is approached arthroscopically, forward flexion can be increased to gain better exposure. We will often angle the bed 45 degrees away from anesthesia and place the visualization tower across the surgical field and at eye level to the surgeon.

Related posts:

23 Double-Row Labral Repair 22 Role of Remplissage in Anterior Shoulder Instability 21 Open Anterior Stabilization (Bankart/Capsular Shift) 29 Distal Tibia Allograft for Failed Latarjet 30 Partial Humeral Head Replacement: Allograft and Prosthetic 34 Modified McLaughlin for Posterior Dislocation

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