Selective capsular shift technique for anterior and anterior-inferior glenohumeral instability.

The diagnosis and treatment of patients with unstable shoulders present unique challenges. In the setting of recurrent anterior and anterior-inferior glenohumeral instability, treatment options vary. In acute, traumatic episodes of instability, especially in young individuals, labral detachment usually occurs 6 , 30 and can be associated with abnormal capsular laxity. In this case, the diagnosis is usually more apparent than in the case of repetitive microtrauma or atraumatic instability, in which abnormal capsular laxity is the primary problem. When a surgical approach is chosen, however, the operative technique must allow for complete flexibility to address all aspects of the surgical pathology, especially when intraoperative decisions deviate from the preoperative plan. Traditional procedures that were recommended to address anterior patterns of glenohumeral instability were considered successful if the operation eliminated additional instability. A new, broader definition of “success” after instability surgery takes into account the specific functional demands of individuals, especially athletes whose sports require overhead motion. A successful surgical procedure for glenohumeral instability restores stability and ensures painless and functional range of motion based on a patient's requirements. The benefits of an anatomic reconstruction that directly addresses the soft-tissue pathology in anterior glenohumeral instability are being increasingly recognized. * The selective capsular shift is an open procedure that offers the versatility necessary to address the pathology that may be encountered. 40 , 49 This technique is useful to treat soft-tissue or bony abnormalities of the capsular attachment on the glenoid and capsular injury in its midsubstance or at the humeral attachment. The selective capsular shift is a modification of the capsular shift procedure described by Neer et al 25 , 26 and Bigliani et al 9 but offers potential advantages when the operation has progressed to the stage of capsular repair by limiting the extent of the capsular shift to restore normal capsular anatomy. This is achieved with the selective tensioning of the inferior and superior capsule by varying arm position during the capsular repair. In this manner, stability is restored while the potentially harmful effects of loss of external rotation can be avoided. This is especially important in athletes who use overhead motions. Experimental studies have demonstrated the characteristics and importance of the inferior glenohumeral ligament as the primary static stabilizer against anterior-inferior translation of the humeral head when the arm is abducted and externally rotated and the ligament is placed under significant tension. 8 , 24 , 36 , 38 , 43 , 46 Conversely, the superior and middle glenohumeral ligaments function to restrict anterior-inferior translation when the arm is adducted and externally rotated and are in maximal tension in this arm position. 46 With this in mind, repair of the inferior capsular flap and the superior capsular flap are performed separately, with the arm in positions closer to the end ranges of motion to achieve static stability but avoid overtightening of the capsule. The capsule tensioned in this manner during the selective capsular shift helps to preserve normal glenohumeral rotation and prevent loss of external rotation. The capsular shift is performed laterally because the release of the capsular attachment on the humerus is believed to allow for a more precise repair. This is suggested by the “funnel” shape of the capsule and its attachments, which is more narrow at the glenoid and wider near the humerus. 38 Also, although the capsular attachment to the glenoid labrum does not typically vary in “normal” shoulders, the capsular attachment on the humeral neck can be variable. 29 , 38 These variations include the V-shaped and collarlike humeral attachments of the inferior glenohumeral ligament as described by O'Brien et al. 29 Cooper and Brems 12 suggested that a lateral capsular surgical approach, together with increasing external rotation of the arm, allows for exposure more posteriorly and greater advancement of the posterior portion of the capsule to enhance posterior stability in patients with multidirectional instability. Furthermore, instability as a result of a humeral capsular disruption can be addressed during the lateral approach without additional surgical dissection because this can be corrected during the capsular repair. 4 , 22 , 51 , 54 In patients with recurrent anterior-inferior instability who have failed nonoperative treatment, the surgical approach must be individualized based on several factors, including age, activity level, arm dominance, specific sports participation, pattern of instability, tissue quality, cosmesis, and patient expectations. Arthroscopic procedures are becoming more refined and reproducible. Reports suggest improving success rates, depending on the indications, surgical pathology, operative techniques, and devices used, but the results are not uniform. * The surgical dissection of the open approach is avoided with an arthroscopic approach, which results in less scarring, but capsular tensioning is more precise in an open procedure, particularly with the selective shift technique. Open and arthroscopic procedures require specific, but separate, skills when repairing a labral detachment and when shifting the capsule. Operative time is also related to the skill level of the surgeon. One other aspect of the open procedure is the closure of the rotator interval. Open treatment for isolated rotator interval lesions has been described, 14 , 27 and techniques to repair this arthroscopically have been reported. 16 , 42 Addressing the rotator interval is not always discussed in the descriptions of arthroscopic techniques for anterior and anterior-inferior glenohumeral instability. 13 , 23 , 33 , 34 , 41 , 44 , 53 Typically, in an open capsular shift, the superior edge of the capsule is sutured to the tissue at the anterior edge of the supraspinatus to close the interval. 9 , 25 , 26 , 49 Consideration must be given to this aspect of the instability pattern and addressed during any procedure, open or arthroscopic, to correct this abnormality, when present.