Treatment of shoulder instability: Capsular shift, posterior capsular shift, arthroscopic capsular shift

Capsular shift

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  The patient is carefully examined and questioned preoperatively to determine the probable direction of greatest instability. After delivery of a general anesthetic, the instability of the shoulder is evaluated again. Anterior instability is tested with the arm in external rotation and extension at various levels of abduction. Inferior instability is tested with the arm in 0 degrees and 45 degrees of abduction. Posterior instability is tested with the arm in internal rotation at various levels of forward elevation. If this examination and the preoperative evaluation correlate with anteroinferior instability, use an anterior approach.

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  Place the patient in a tilted position with the front and the back of the shoulder exposed. Drape the arm free. Attach an arm board to the side of the table.

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  Make a 9-cm incision in the skin creases from the anterior border of the axilla to the coracoid process.

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  Develop the deltopectoral interval medial to the cephalic vein and retract the deltoid laterally. Divide the clavipectoral fascia and retract the muscles attached to the coracoid process medially.

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  With the arm in external rotation, divide the superficial half of the thickness of the subscapularis tendon transversely 1 cm medial to the biceps groove. Leave the deep half of the subscapularis tendon attached to reinforce the anterior aspect of the capsule and tag the superficial half of the tendon with stay sutures and retract it medially. It is important that this superficial portion of the subscapularis tendon be free so that the action of the subscapularis muscle is not tethered ( Fig. 19.1 ).

  

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  Close the cleft between the middle and superior glenohumeral ligaments with nonabsorbable sutures.

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  Make a T-shaped opening by incising between the middle and inferior glenohumeral ligaments ( Fig. 19.2 ; a and b depict superior and inferior flaps, respectively).

  

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  With a flat elevator to protect the axillary nerve and with the arm in external rotation, develop a capsular flap by detaching the reinforced part of the capsule containing the inferior glenohumeral ligament from the inferior aspect of the neck of the humerus around to the posterior aspect of the neck of the humerus ( Fig. 19.3 , b).

  

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  Inspect the interior of the joint and remove any osteochondral bodies or tags of labrum.

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  Test for posterior instability with and without forward traction on the inferior capsular flap to estimate the new location for the flap.

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  Using curets and a small gouge, make a shallow slot in the bone at the anterior and inferior sulcus of the neck of the humerus, as shown in aforementioned ( Fig. 19.3 , c). Suture the capsular flap to the stump of the subscapularis tendon and to the part of the capsule that remains on the humerus so that the capsular flap is held against the slot of raw bone. Suture anchors can be used to secure the capsule and are generally preferred.

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  The tension on the capsular flap that is selected must eliminate the inferior pouch and reduce the posterior capsular redundancy. Suture the inferior flap ( Fig. 19.3 , b) first and draw the superior flap ( Fig. 19.3 , a) down over it and suture it so as to cause the middle glenohumeral ligament to reinforce the capsule anteriorly and to act as a sling against inferior subluxation ( Fig. 19.4 ).

  

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  Hold the arm in slight flexion and about 10 degrees of external rotation on the armboard while the anterior portion of the capsule is reattached with nonabsorbable sutures. Bigliani et al. recommended repairing the capsule with the arm held in approximately 25 degrees of external rotation and 20 degrees of abduction. For throwers, they recommended relatively more abduction and external rotation to ensure full range of motion.

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  Bring the subscapularis tendon over the reattached anterior portion and reattach the tendon at its normal location.

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  After closure of the deltopectoral interval with absorbable sutures and after closure of the skin with a skin stitch, maintain the arm at the side in neutral flexion-extension and in about 20 degrees of internal rotation by light plastic splints.