The “Sublabral Window” in Arthroscopic Posterior Shoulder Instability Surgery: Description of a Technique for Safe Posterior Glenoid Preparation  Kushal V. Patel, M.D., Jonathan T. Bravman, M.D., Eric McCarty, M.D.  Arthroscopy Techniques  Volume 5, Issue 3, Pages e433-e439 (June 2016) DOI: 10.1016/j.eats.2016.01.024 Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 1 (A) The 30° arthroscope is positioned in the anterior portal through a 6.5-mm clear threaded flexible cannula showing a left shoulder posterior labral tear. The patient is positioned in the right lateral decubitus position with the left arm in a 3-point distraction system and STaR Sleeve (Arthrex). A posterior portal has already been established. Either a 6.5-mm clear threaded flexible cannula or 5.5-mm universal cannula is positioned in the posterior portal. The 6.5-mm cannula has an advantage in that it can subsequently be used for suture anchor placement and labral repair. The 5.5-mm universal cannula may not be wide enough for instrumentation. (B) A 15° square tissue elevator is used to liberate and mobilize the labrum from the posterior glenoid rim. The junction between the normal and torn posterior labrum is identified, and the tissue elevator is used to liberate the torn labrum to this junction. (C) A switching stick (4 mm extra long) is positioned intra-articularly as the cannula is retracted superficial to the capsule. The switching stick is then positioned deep to the entire capsulolabral tissue. The cannula can be advanced over the switching stick, allowing safe use of motorized arthroscopic instruments. (D) An arthroscopic resector (4.0 mm) or a hooded straight round burr (4.0 mm) is used to irritate/prepare the soft tissue and freshen the glenoid rim. This is achieved through the cannula that has already been placed deep to the capsulolabral tissue. It should be noted that the integrity of the capsulolabral tissue is not violated. (E-G) After the preparatory work is completed, the cannula in the posterior portal is now repositioned superficial to the capsulolabral tissue in a similar manner with a switching stick. The labral tear can now be repaired. We use all-suture–based anchors (1.5-mm Juggerknot Soft Anchor; Zimmer Biomet). Sutures are shuttled using a suture-passing system (Spectrum II Tissue Repair System; ConMed), and arthroscopic knots are tied. Depending on the inferior extension of the posterior labral tear, a posterior-inferior portal may be necessary. Arthroscopic knots are tied to secure the labral tissue to the glenoid rim. Patients with an isolated posterior labral tear are placed in an external rotation sling (UltraSling III ER; DJO Global). The black diamond indicates the humeral head; black oval, sublabral window; black star, posterior labrum; white diamond, glenoid; and white star, posterior portal. Arthroscopy Techniques 2016 5, e433-e439DOI: (10.1016/j.eats.2016.01.024) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions

Fig 2 (A) The 30° arthroscope is positioned in the anterior portal through a 6.5-mm clear threaded flexible cannula showing a right shoulder posterior labral tear. The patient is positioned in the left lateral decubitus position with the right arm in a 3-point distraction system and STaR Sleeve (Arthrex). A posterior portal has already been established. Either a 6.5-mm clear threaded flexible cannula or 5.5-mm universal cannula is positioned in the posterior portal. The 6.5-mm cannula has an advantage in that it can subsequently be used for suture anchor placement and labral repair. The 5.5-mm universal cannula may not be wide enough for instrumentation. (B) A 15° square tissue elevator is used to liberate and mobilize the labrum from the posterior glenoid rim. The junction between the normal and torn posterior labrum is identified, and the tissue elevator is used to liberate the torn labrum to this junction. (C) A switching stick (4 mm extra long) is positioned intra-articularly as the cannula is retracted superficial to the capsule. The switching stick is then positioned deep to the entire capsulolabral tissue. The cannula can be advanced over the switching stick, allowing safe use of motorized arthroscopic instruments. (D-F) An arthroscopic resector (4.0 mm) or a hooded straight round burr (4.0 mm) is used to irritate/prepare the soft tissue and freshen the glenoid rim. This is achieved through the cannula that has already been placed deep to the capsulolabral tissue. It should be noted that the integrity of the capsulolabral tissue is not violated. (G, H) After the preparatory work is completed, the cannula in the posterior portal is now repositioned superficial to the capsulolabral tissue in a similar manner with a switching stick. The labral tear can now be repaired. We use all-suture–based anchors (1.5-mm Juggerknot Soft Anchor; Zimmer Biomet). Sutures are shuttled using a suture-passing system (Spectrum II Tissue Repair System; ConMed), and arthroscopic knots are tied. Depending on the inferior extension of the posterior labral tear, a posterior-inferior portal may be necessary. Arthroscopic knots are tied to secure the labral tissue to the glenoid rim. Patients with an isolated posterior labral tear are placed in an external rotation sling (UltraSling III ER; DJO Global). The black diamond indicates the humeral head; black oval, sublabral window; black star, posterior labrum; white diamond, glenoid; and white star, posterior portal. Arthroscopy Techniques 2016 5, e433-e439DOI: (10.1016/j.eats.2016.01.024) Copyright © 2016 Arthroscopy Association of North America Terms and Conditions