Dic 13

The Posterolateral Portal: Optimizing Anchor Placement and Labral Repair at the Inferior Glenoid

FUENTE:
http://www.arthroscopytechniques.org/article/S2212-6287(13)00030-3/fulltext

The Posterolateral Portal: Optimizing Anchor Placement and Labral Repair at the Inferior Glenoid

Received 16 December 2012; accepted 15 February 2013. published online 03 June 2013.

Videos (1):
Video 1. 
A narrated overview of the use of the posterolateral portal in arthroscopic capsulolabral repair of the inferior glenoid, focusing on how this portal improves suture shuttling and anchor placement.

Article Outline

Abstract 

The Bankart lesion is considered the critical lesion in anterior shoulder instability, in which the anteroinferior glenoid labrum separates from the glenoid rim. Technical advances in arthroscopy have ushered in a shift from open to arthroscopic Bankart repair. When one is performing an arthroscopic Bankart repair, proper portal placement is critical for success in labral preparation and anchor placement. Frequently, standard anterior portals are insufficient for inferior glenoid anchor placement and suture shuttling. The posterolateral portal—located 4 cm lateral to the posterolateral corner of the acromion—simplifies and improves anchor placement, trajectory, and anatomic capsulolabral repair of the inferior glenoid. We present our preferred technique for capsulolabral repair of the inferior glenoid.
 
Anterior glenohumeral dislocation is commonly associated with a Bankart lesion, in which the anteroinferior glenoid labrum separates from the glenoid rim. Technical advances in arthroscopy have ushered in a shift from open to arthroscopic Bankart repair. Arthroscopic Bankart repair outcomes now parallel those of open Bankart repairs. When one is performing an arthroscopic Bankart repair, proper portal placement is critical for success in labral preparation and anchor placement. Moreover, recurrent instability is anterior and inferior. Therefore it is critical to anatomically reduce the anterior-band of the inferior glenohumeral ligament. Frequently, standard portals are insufficient for optimal repair, and therefore authors have used various accessory portals.1
In our experience with arthroscopic Bankart repair, the 7-o’clock posterolateral portal provides optimal access to the inferior glenoid. Labral suture passage, knot tying in the anteroinferior quadrant, and placement of suture anchors at the inferior glenoid are all improved with this approach. We present our preferred technique for arthroscopic Bankart repair, emphasizing the use of the 7-o’clock posterolateral portal. Video 1 shows a narrated review of the surgical technique.

Surgical Technique 

Patient Setup 

We prefer an interscalene block followed by general anesthesia. The patient is placed in the lateral decubitus position because we find that this provides the best possible access to and visualization of the entire capsulolabral complex. The operative extremity is examined with the patient under anesthesia to confirm the pattern of instability and to refine the operative plan, including estimating the correct amount of capsular plication. Subsequently, the patient’s operative arm is prepared and draped in standard sterile fashion and suspended by gentle traction in slight abduction and forward flexion. A marking pen is used to outline the acromion, distal clavicle, and coracoid process and to mark the portal sites. The posterolateral portal is marked 4 cm off of the posterolateral acromion (Fig 1). One may trace the trajectory of the posterior clavicle laterally as confirmation of the appropriate position.
  • View full-size image.
  • Fig 1. 
    For arthroscopic inferior labral repair with the posterolateral portal, the patient is positioned in the lateral decubitus position. We use a posterior portal (3) 2 cm inferior to the posterolateral corner of the acromion and an anterosuperior portal (1) in the rotator interval just anterior to the biceps. The posterolateral portal (2) is created by an inside-out technique with an 18-gauge spinal needle, located approximately 4 cm lateral to the posterolateral corner of the acromion (following the trajectory of the posterior border of the clavicle laterally). The arthroscope is in the anterosuperior portal for optimal visualization.

Initial Portal Placement and Diagnostic Arthroscopy 

A posterior viewing portal is created approximately 2 cm inferior to the posterolateral corner of the acromion, and a 30° arthroscope is inserted. An anterosuperior portal is then created proximal in the rotator interval, just anterior to the biceps, by use of 18-gauge spinal needle localization, and a 7-mm cannula is placed. A diagnostic arthroscopy of the glenohumeral joint is performed to identify the Bankart lesion and identify concomitant injury to other structures including the remainder of the capsulolabral complex, long head of the biceps tendon, rotator cuff, humeral head Hill-Sachs lesion, and glenoid bone stock.

Labral Preparation 

After a Bankart lesion is confirmed, the arthroscope is transferred to the anterosuperior portal for optimal viewing of the anteroinferior glenoid (Fig 2A). Proper labral preparation is critical to successful arthroscopic Bankart repair. Under arthroscopic visualization from the anterosuperior portal, a tissue liberator, from the anteroinferior working portal, is used to peel the labrum from the glenoid at the labrum-bone interface until subscapularis muscle fibers are visualized. This confirms adequate mobilization, because the capsulolabral complex often self-reduces to its native footprint after this maneuver. Next, a tissue rasp or burr is used to create punctate glenoid bleeding.
  • View full-size image.
  • Fig 2. 
    (A) Placing the arthroscope in the anterosuperior portal provides optimal visualization of inferior capsulolabral pathology, indicated by an asterisk. (B) The posterolateral portal provides an excellent trajectory for inferior glenoid anchor placement, with drilling for anchor placement in a trajectory that is nearly perpendicular to the floor. (C) After anchor placement in the inferior glenoid through the posterolateral portal, we retain sutures in the posterolateral portal and place the cannula in the posterior portal for improved suture management during capsulolabral repair. (D) We insert the Spectrum through the posterior portal to grasp the capsule anterior to the anchor, avoiding the axillary nerve and enhancing plication of the capsular pouch. One must use a right Spectrum in a right shoulder and vice versa. (E) Sutures are tied with a sliding knot followed by alternating half-hitches, with the knot away from the articular surface.

Posterolateral Portal 

Using 18-gauge spinal needle localization, we then create a posterolateral portal percutaneously for anchor placement (Table 1). This portal is located approximately 4 cm lateral to the posterolateral corner of the acromion (following the trajectory of the posterior border of the clavicle laterally). We create this portal by an inside-out technique with an 18-gauge spinal needle. The spinal needle trajectory is nearly perpendicular to the floor, generally aimed at the coracoid, and hugging the humeral head.

Table 1. Pearls of Posterolateral Portal Placement
1. Use an inside-out technique with an 18-gauge spinal needle to localize the portal trajectory.
2. The spinal needle trajectory should be nearly perpendicular to the floor, generally aimed at the coracoid, and hugging the humeral head.
3. The incision should be approximately 4 cm lateral to the posterolateral corner of the acromion.
4. Confirm the location by following the trajectory of the posterior border of the clavicle laterally.
5. Use a percutaneous trocar for anchor drilling into the glenoid; if desired, a cannula can be used as a working portal.

Anchor Placement 

Closely following the trajectory of the spinal needle, a blunt trocar is passed through the teres minor, passing through the capsule under direct visualization, and is placed at the inferior glenoid. We prefer to gently mallet the trocar into the glenoid as we optimize the trajectory. This minimizes the risk for movement with drilling and the potential for skiving across the glenoid cartilage. The posterolateral portal enables the trocar to be placed 1 to 2 mm from the glenoid rim, minimizing drilling into the articular surface (Fig 2B). Next, the assistant drills and places the anchor (Bio-Fastak; Arthrex, Naples, FL) percutaneously through the posterolateral portal. The sutures are gently pulled to ensure capture before removal of the trocar. The sutures are retained in the posterolateral portal to facilitate suture management (Fig 2C).

Labral Repair 

After the anchor is successfully placed, we cannulate the posterior portal using a switching stick to enable suture passage and knot tying. This approach enables the Spectrum (ConMed Linvatec, Largo, FL) to grasp the anterior capsule anterior to the anchor, thus avoiding the axillary nerve and bringing the labrum back to the inferior glenoid (Fig 2D). On the basis of our experience, this angle enhances plication of the capsular pouch. A key point is that the surgeon uses the Spectrum with the opposite angle to that needed anteriorly. For example, we use a right Spectrum in a right shoulder. Moreover, one can titrate the amount of plication based on the laxity identified clinically or during the examination with the patient under anesthesia. Alternatively, once the anchor is placed, we may approach the labral repair anteriorly from the anteroinferior portal.
The sutures are shuttled by use of a simple hoop suture configuration, because this best allows the appropriate tensioning and bumper re-creation at the inferior glenoid. The suture is secured with a sliding knot, followed by alternating half-hitches (Fig 2E). The knot should be away from the articular surface. We recommend that at least 3 suture anchors be used between the 3- and 6-o’clock position for arthroscopic Bankart repair so as to achieve re-creation of the glenoid labrum and desired capsular plication. Additional anchors are placed along the anterior glenoid approximately 5 to 7 mm apart by use of the anteroinferior working portal.

Discussion 

Because of technical advances in arthroscopic instability repair, arthroscopic Bankart repair is becoming more commonly performed, with outcomes approaching those of the gold standard, open repair. Standard arthroscopic portals provide insufficient visualization and instrumentation access to the inferior glenoid. Our approach to arthroscopic Bankart repair uses the posterolateral portal, which has been previously described.2 In our experience, the advantages of the posterolateral portal are enhanced ability to place anchors in the inferior glenoid at an improved trajectory, improved anteroinferior knot tying, facilitation of anteroinferior labral repair, and anatomic reduction of the inferior glenohumeral ligament (Table 2).

Table 2. Benefits and Limitations of Posterolateral Portal
Benefits Limitations
Enhanced ability to place anchors in inferior glenoid at improved trajectory for anchor placement Distance of 35 mm from axillary nerve
Facilitation of anteroinferior labral repair
Anatomic reduction of inferior glenohumeral ligament
In 2002 Davidson and Rivenburgh3 first described the 7-o’clock posterolateral portal in cadaveric shoulders as a way to obtain improved working access to the inferior glenoid. This portal was found to enter the glenohumeral joint through the teres minor tendon at a safe distance from the suprascapular nerve and artery (28 ± 2 mm) and from the axillary nerve and posterior circumflex humeral artery (39 ± 4 mm).3 Difelice et al.4 found in a cadaveric study that a similarly placed posterolateral portal had a distance of 34 ± 5 mm from the axillary nerve and 29 ± 3 mm from the suprascapular nerve. These studies also found that arm position did not change the distance from the portal to the neurovascular structures.3, 4The reported uses of the posterolateral portal include arthroscopic management of humeral avulsion of the glenohumeral ligament,5 posterior instability,6 and Bankart lesions.7

Supplementary data 

Video 1. A narrated overview of the use of the posterolateral portal in arthroscopic capsulolabral repair of the inferior glenoid, focusing on how this portal improves suture shuttling and anchor placement.

References 

  1. Seroyer ST, Nho SJ, Provencher MT, Romeo AA. Four-quadrant approach to capsulolabral repair: An arthroscopic road map to the glenoid. Arthroscopy. 2010;26:555–562

  2. Nord KD, Brady PC, Yazdani RS, Burkhart SS. The anatomy and function of the low posterolateral portal in addressing posterior labral pathology. Arthroscopy. 2007;23:999–1005

  3. Davidson PA, Rivenburgh DW. The 7-o’clock posteroinferior portal for shoulder arthroscopy. Am J Sports Med. 2002;30:693–696

  4. Difelice GS, Williams RJ, Cohen MS, Warren RF. The accessory posterior portal for shoulder arthroscopy: Description of technique and cadaveric study. Arthroscopy. 2001;17:888–891

  5. Parameswaran AD, Provencher MT, Bach BR, Verma N, Romeo AA. Humeral avulsion of the glenohumeral ligament: Injury pattern and arthroscopic repair techniques. Orthopedics. 2008;31:773–779

  6. Bradley JP, Tejwani SG. Arthroscopic management of posterior instability. Orthop Clin North Am. 2010;41:339–356

  7. Baker CL, Romeo AA. Combined arthroscopic repair of a type IV SLAP tear and Bankart lesion. Arthroscopy. 2009;25:1045–1050
 The authors report that they have no conflicts of interest in the authorship and publication of this article. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of Defense, or the US government.
PII: S2212-6287(13)00030-3
doi:10.1016/j.eats.2013.02.011
© 2013 Arthroscopy Association of North America. All rights reserved.