Arthroscopic Capsular Shift / Plication for Shoulder Instability

Indication. Symptomatic multidirectional or atraumatic shoulder instability with a documented patulous capsule, after failure of a structured rehabilitation programme of at least 6 months, and in the absence of significant bone loss. Confirm the diagnosis with a positive sulcus sign and positive apprehension in more than one direction, plus arthroscopic confirmation of global capsular redundancy and a positive drive-through sign. Relative indications include traumatic anterior instability with associated capsular stretch or redundancy in addition to a Bankart lesion, overhead athletes or throwers with a subtle MDI pattern that has failed non-operative management, and patients with connective-tissue disorders (Ehlers-Danlos, Marfan) and symptomatic laxity after failed rehabilitation. Assess the whole instability pattern before committing. Quantify glenoid bone loss (CT with 3D reconstruction or arthroscopic measurement) and humeral bone loss (the Hill-Sachs engagement test). The single decision that determines whether a soft-tissue plication is even appropriate is whether significant bone loss is present:

Contraindications. Absolute: glenoid bone loss greater than 15-20 percent or an off-track engaging Hill-Sachs lesion, active infection or uncontrolled inflammatory arthropathy, and a patient unable or unwilling to comply with the rehabilitation protocol. Relative: isolated unidirectional instability without capsular redundancy (better served by targeted labral repair), a previous failed capsular shift with scarring that precludes safe arthroscopic plication, and overhead athletes in whom even modest loss of external rotation would be career-ending. Consent specifically for residual stiffness and loss of external rotation, recurrent instability (5-12 percent), a small risk of axillary nerve injury (less than 1 percent with proper technique), chondral or suture abrasion, and (in connective-tissue disorders) a higher recurrence rate and the possibility of needing a revision or open procedure. Setup. Beach-chair position with the scapula supported and the arm free in a pneumatic or mechanical arm holder that allows controlled abduction, rotation and flexion. General anaesthesia with an interscalene block for postoperative analgesia; muscle relaxation is essential for adequate distraction and visualisation. Before any portal, perform a full examination under anaesthesia documenting range of motion, the sulcus sign, load-and-shift in anterior and posterior directions, and apprehension/relocation in multiple positions — this baseline defines how much plication is required.

The goal is to reduce excessive capsular volume in a balanced fashion — taking up the redundant inferior, anterior and posterior capsule so the humeral head sits centred on the glenoid — while protecting the axillary nerve and preserving functional external rotation. The exposure is arthroscopic: standard posterior and anterior portals give access to the whole capsular ring. Capsular anatomy you must know before plication. The inferior glenohumeral ligament complex (IGHL) is the primary static restraint to inferior translation and the structure you are tightening. It has an anterior band (from the anteroinferior labrum at the 5-6 o'clock position to the humeral anatomic neck — restrains anterior and inferior translation in abduction and external rotation), a posterior band (from the posteroinferior labrum at the 7-8 o'clock position — restrains posterior and inferior translation in abduction and internal rotation), and the axillary pouch between them, which holds the majority of the excess volume in MDI. The rotator interval is the capsular gap between the superior border of subscapularis and the anterior border of supraspinatus, containing the coracohumeral and superior glenohumeral ligaments; when patulous it allows inferior and posterior translation. The drive-through sign — easy passage of the arthroscope from posterior to anterior across the joint — is your intraoperative measure of excessive volume, and its elimination is the endpoint of plication.

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Suture, anchors and fixation. Non-absorbable braided polyethylene suture (No. 2 FiberWire, Orthocord or equivalent) is standard — strong enough to hold the plication through rehabilitation, small enough to minimise cartilage abrasion. Small glenoid-rim anchors (2.4-2.9 mm) loaded with non-absorbable suture are used when the labrum is attenuated or extra fixation is needed (placed at 5, 6 and 7 o'clock for inferior work, 3 and 9 o'clock for anterior/posterior); bioabsorbable or all-suture anchors are preferred in young patients to avoid permanent hardware. Knotless devices reduce operative time and knot prominence and are useful in the inferior quadrant where a knot stack can irritate the capsule. Use curved passers with protective sheaths to minimise chondral injury.

Rehabilitation | Phase | Timing | Immobilisation | Therapy | |-------|--------|----------------|---------| | 1 | 0-2 weeks | Sling for comfort only | Passive and active-assisted forward flexion to 90 degrees, external rotation to 30 degrees in the scapular plane; pendulums; isometric cuff activation | | 2 | 2-6 weeks | Wean sling as comfort allows | Active-assisted to full forward flexion, external rotation to 45-60 degrees; light scapular stabilisation; no resisted external rotation or elevation | | 3 | 6-12 weeks | None | Full active range of motion; progressive rotator-cuff and periscapular strengthening; proprioceptive and neuromuscular training | | 4 | 3-6 months | None | Sport-specific drills and plyometrics; graded throwing programme from 4-5 months; full return to contact or overhead sport at 6-9 months | Key milestones. By 6 weeks aim for external rotation at the side greater than 45 degrees and forward flexion greater than 140 degrees; by 3 months external rotation at 90 degrees abduction within 15 degrees of the contralateral side; by 6 months full symmetric range and motion and strength greater than 80 percent of the contralateral side. Expected outcomes. In appropriately selected patients the recurrence rate is 5-12 percent at 5 years, patient satisfaction is 85-92 percent, and 70-85 percent of overhead athletes return to their pre-injury sport level. Average loss of external rotation is 5-15 degrees and is titratable. The principal limitation in athletes is residual stiffness rather than recurrent instability. Factors associated with poorer outcomes include connective-tissue disorders (higher recurrence, may require an open shift), workers' compensation or litigation, non-compliance with rehabilitation, an over-ambitious return to sport before 6 months, and pre-existing glenohumeral arthritis. Patients with MDI and connective-tissue disorders carry a lifelong risk of recurrence in other joints — capsular shift addresses the shoulder but does not alter the underlying collagen disorder, so activity modification and ongoing strengthening are lifelong. Complications

Epidemiology. Multidirectional instability typically presents in the second and third decades and is common in overhead athletes, gymnasts and patients with generalised ligamentous laxity or a connective-tissue disorder. A substantial proportion of patients are bilateral. It is fundamentally a capsular-volume problem rather than a unidirectional soft-tissue tear, which is why dynamic-stabiliser rehabilitation is the first line and why volume reduction — not labral repair alone — is the operative goal when rehabilitation fails. Pathoanatomy. MDI arises from a globally redundant, patulous capsule rather than from a single discrete lesion. The inferior glenohumeral ligament complex is attenuated, the axillary pouch holds excess volume, and the rotator interval is often widened — together allowing inferior, anterior and posterior translation. In atraumatic MDI poor dynamic stabilisation (rotator cuff and periscapular weakness, altered proprioception) compounds the laxity. The drive-through sign is the arthroscopic correlate of this global redundancy. Comparison with the open inferior capsular shift. Open inferior capsular shift remains the benchmark volume-reducing procedure. Arthroscopic plication achieves a comparable reduction in capsular volume with less postoperative stiffness and faster recovery when performed by experienced surgeons on appropriately selected patients. In severe global laxity or connective-tissue disorders an open shift may still be preferred for a more robust inferior shift.

Key evidence. Cadaveric work quantifies what the operation achieves: 4-6 plication sutures placed in a balanced four-quadrant fashion reduce glenohumeral volume by 30-50 percent, comparable to an open shift, while rotator interval closure adds a further 10-15 percent reduction (at the cost of 10-25 degrees of external rotation if over-closed). Cadaveric mapping of the axillary nerve shows that abduction and external rotation increase the nerve-to-capsule distance from about 1.5 cm to 3.2 cm, and that sutures placed within 1 cm of the inferior labrum with the arm adducted place the nerve at highest risk — the anatomical basis for the arm-position rule. Clinical series of arthroscopic plication in MDI report recurrence rates of 5-12 percent at 2-5 years with appropriate selection, and overhead-athlete return-to-sport rates of 70-85 percent, with over-constraint (external-rotation loss greater than 20 degrees) the principal cause of failure to return. A randomised comparison of open and arthroscopic capsular shift found no significant difference in recurrence or patient-reported outcomes at 5 years, with less stiffness and faster return to work in the arthroscopic group.