Arthroscopic Posterior Labral Repair (Posterior Shoulder Instability)

Indication. Symptomatic, recurrent posterior shoulder instability - typically pain and subluxation rather than frank dislocation - with a documented posterior labral (reverse Bankart) tear on MRI or MR-arthrography, that has failed non-operative management (a minimum of 3 to 6 months of structured physiotherapy focusing on scapular stabilisation, rotator-cuff strengthening and proprioception) and a positive jerk test or Kim test reproducing the patient's symptoms. Absolute indications - Recurrent posterior subluxation or dislocation with a documented posterior labral tear on MRI or MRA.

• Failed non-operative management (a minimum of 3 to 6 months of compliant, structured physiotherapy).
• A positive jerk test or Kim test reproducing symptoms with corresponding labral pathology on imaging. Relative indications - A contact or overhead athlete with functional instability limiting sport.
• A posterior labral tear with greater than 50 percent detachment, or associated posterior capsular redundancy.
• A reverse Hill-Sachs lesion of less than 20 percent of the articular surface that does not engage. Contraindications. These are the cases where an all-arthroscopic soft-tissue repair is the wrong operation and a posterior bone block (or combined procedure) is required instead. - Absolute: posterior glenoid bone loss greater than 25 percent or glenoid retroversion greater than 20 degrees (bone block augmentation required); an engaging reverse Hill-Sachs lesion greater than 25 percent of the humeral head articular surface; active infection or uncontrolled medical comorbidity.
• Relative: multidirectional instability with a predominant posterior component (consider a global capsular shift or arthroscopic pancapsular plication rather than an isolated posterior repair); poor tissue quality (Ehlers-Danlos, prior failed thermal capsulorrhaphy); a patient unable or unwilling to comply with the rehabilitation protocol. Try non-operative first. Structured physiotherapy - scapular stabilisation, rotator-cuff strengthening and proprioceptive training - resolves symptoms in approximately 50 to 70 percent of patients with first-time or low-demand posterior instability. Contact athletes and patients with significant labral detachment have lower success rates and warrant earlier surgical referral. Declare non-operative failure only after a minimum of 3 to 6 months of compliant therapy. Why arthroscopic, and when open. Modern arthroscopic capsulolabral reconstruction gives 85 to 95 percent success in properly selected patients, with lower morbidity, faster return to sport and better cosmesis than an open approach, and it permits simultaneous treatment of associated pathology (SLAP tears, rotator-cuff lesions, chondral injury). An open posterior approach is reserved for cases needing bone-block augmentation, or when arthroscopic access is limited by body habitus or prior surgery.

Consent specifically for recurrence (8 to 15 percent overall, higher in contact athletes), stiffness and loss of external rotation (5 to 12 percent), chondral injury, axillary nerve injury (less than 1 percent with correct portal placement), and the possibility of conversion to an open procedure or bone block if bone loss is greater than expected.

The goal: restore the posterior labral bumper anatomically with at least three suture anchors, plicate a redundant posterior capsule, and confirm stable, congruent glenohumeral mechanics - all while protecting the axillary nerve. The exposure here is portal placement: the standard posterior and anterior-superior viewing portals are established first, then the accessory 7 o'clock working portal is added under needle localisation. The lateral decubitus position with balanced traction opens the posteroinferior joint and is what makes the inferior anchor reachable.

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Rehabilitation | Phase | Timing | Immobilisation & restrictions | Therapy & goals | |-------|--------|-------------------------------|-----------------| | 1 - Protection | 0 to 6 weeks | Sling with abduction pillow; no active internal rotation or cross-body adduction | Pendulum exercises; elbow, wrist and hand ROM from day 1; passive/active-assisted forward elevation to 90 degrees only; isometric external rotation from week 4 | | 2 - Motion | 6 to 12 weeks | Wean sling at 6 weeks | Progressive active ROM in all planes (goal full ROM by 12 weeks); gentle posterior capsular stretch; scapular stabilisation; no resistance until pain-free full ROM | | 3 - Strengthening | 12 to 18 weeks | Splint for heavy tasks only | Progressive rotator-cuff and scapular strengthening; closed-chain and proprioceptive work; sport-specific drills from week 16 | | 4 - Return to sport | 5 to 9 months | Functional brace considered for contact athletes in first season | Non-contact return at 4 to 5 months (at least 80 percent contralateral strength); contact clearance at 6 to 9 months requiring full pain-free ROM, symmetric strength and negative apprehension |

Epidemiology. Posterior shoulder instability is far less common than anterior, and the presentation is often subtle - recurrent subluxation and pain rather than frank dislocation. At-risk groups include contact athletes (football linemen), weightlifters (bench-press loading), and patients with seizures or electrical injury. Bilateral involvement occurs in up to 50 percent of atraumatic cases, so the contralateral shoulder should always be screened. Pathoanatomy. The posterior labrum is a fibrocartilaginous ring attached to the glenoid rim that deepens the socket by approximately 50 percent and anchors the posterior capsule and the posterior band of the inferior glenohumeral ligament. Detachment of the posterior labrum (the reverse Bankart lesion) allows posterior translation of the humeral head and is the primary pathology in traumatic posterior instability. The posterior capsule is thinner than the anterior, blends with the infraspinatus tendon, and is commonly redundant - which is why plication is performed in the same sitting as the labral repair. Glenoid version and bone loss. Normal glenoid version is 0 to 7 degrees of retroversion. Retroversion greater than 15 degrees, or posterior glenoid bone loss greater than 20 percent of the glenoid width, significantly increases the risk of failure after soft-tissue repair alone. Bone loss is quantified on 3D CT using the circle (or Pico) method on the en-face glenoid view. Reverse Hill-Sachs lesion. An anterior humeral-head impaction fracture sustained when the head strikes the posterior glenoid rim during posterior dislocation. Lesions involving greater than 20 percent of the articular surface, or those that engage the glenoid rim in internal rotation, require an additional procedure (remplissage, bone grafting) at the time of labral repair.

Key evidence. Bradley's prospective series established arthroscopic capsulolabral reconstruction as reliable in selected patients (good-to-excellent outcomes in the great majority, low recurrence). Robinson and Aderinto's review defined the diagnostic value of the provocative tests (jerk test around 97 percent sensitive and 90 percent specific) and the central importance of bone-loss quantification. DeLong and colleagues' meta-analysis confirmed an overall recurrence near 8 percent but a clearly higher rate in contact athletes - the basis for counselling and for considering bone augmentation. Bois and colleagues quantified glenoid bone loss in posterior instability and showed the steep rise in recurrence above 20 percent that bone-block augmentation offsets. The consistent message across the literature: arthroscopic repair is effective when bone loss is modest and the lesion is non-engaging, but bone loss greater than 20 percent (or an engaging reverse Hill-Sachs) must be identified pre-operatively and augmented.